US20060197413A9 - Actuator Device - Google Patents
Actuator Device Download PDFInfo
- Publication number
- US20060197413A9 US20060197413A9 US10/896,769 US89676904A US2006197413A9 US 20060197413 A9 US20060197413 A9 US 20060197413A9 US 89676904 A US89676904 A US 89676904A US 2006197413 A9 US2006197413 A9 US 2006197413A9
- Authority
- US
- United States
- Prior art keywords
- plate member
- plate
- actuators
- actuator
- actuator device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000006073 displacement reaction Methods 0.000 claims description 180
- 230000003287 optical effect Effects 0.000 claims description 85
- 239000003990 capacitor Substances 0.000 claims description 24
- 230000000712 assembly Effects 0.000 claims description 23
- 238000000429 assembly Methods 0.000 claims description 23
- 125000006850 spacer group Chemical group 0.000 abstract description 84
- 239000000758 substrate Substances 0.000 abstract description 84
- 239000010410 layer Substances 0.000 description 79
- 239000000463 material Substances 0.000 description 47
- 230000002950 deficient Effects 0.000 description 33
- 238000000034 method Methods 0.000 description 23
- 230000008569 process Effects 0.000 description 23
- 239000010408 film Substances 0.000 description 19
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 17
- 229920005989 resin Polymers 0.000 description 17
- 239000011347 resin Substances 0.000 description 17
- 229910001928 zirconium oxide Inorganic materials 0.000 description 17
- 230000000052 comparative effect Effects 0.000 description 15
- 230000008859 change Effects 0.000 description 14
- 239000000919 ceramic Substances 0.000 description 13
- 230000007547 defect Effects 0.000 description 13
- 239000011521 glass Substances 0.000 description 13
- 239000000203 mixture Substances 0.000 description 12
- 230000002093 peripheral effect Effects 0.000 description 12
- 229910052751 metal Inorganic materials 0.000 description 10
- 239000002184 metal Substances 0.000 description 10
- 230000004044 response Effects 0.000 description 10
- 239000000945 filler Substances 0.000 description 9
- 230000004048 modification Effects 0.000 description 8
- 238000012986 modification Methods 0.000 description 8
- 239000003822 epoxy resin Substances 0.000 description 7
- 239000007788 liquid Substances 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 7
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 7
- 229920000647 polyepoxide Polymers 0.000 description 7
- 239000011159 matrix material Substances 0.000 description 6
- 229920000178 Acrylic resin Polymers 0.000 description 5
- 239000004925 Acrylic resin Substances 0.000 description 5
- 239000000853 adhesive Substances 0.000 description 5
- 230000001070 adhesive effect Effects 0.000 description 5
- 230000009467 reduction Effects 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 4
- 238000000149 argon plasma sintering Methods 0.000 description 4
- 238000005229 chemical vapour deposition Methods 0.000 description 4
- 239000002131 composite material Substances 0.000 description 4
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical group [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000012212 insulator Substances 0.000 description 4
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 4
- 239000000395 magnesium oxide Substances 0.000 description 4
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 4
- SIWVEOZUMHYXCS-UHFFFAOYSA-N oxo(oxoyttriooxy)yttrium Chemical compound O=[Y]O[Y]=O SIWVEOZUMHYXCS-UHFFFAOYSA-N 0.000 description 4
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 4
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 3
- 239000000654 additive Substances 0.000 description 3
- 230000000996 additive effect Effects 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 229910017052 cobalt Inorganic materials 0.000 description 3
- 239000010941 cobalt Substances 0.000 description 3
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 3
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 239000003779 heat-resistant material Substances 0.000 description 3
- 229910052744 lithium Inorganic materials 0.000 description 3
- 229910052863 mullite Inorganic materials 0.000 description 3
- 238000007650 screen-printing Methods 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- 230000003595 spectral effect Effects 0.000 description 3
- 229910052596 spinel Inorganic materials 0.000 description 3
- 239000011029 spinel Substances 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- 238000002834 transmittance Methods 0.000 description 3
- CBECDWUDYQOTSW-UHFFFAOYSA-N 2-ethylbut-3-enal Chemical compound CCC(C=C)C=O CBECDWUDYQOTSW-UHFFFAOYSA-N 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 2
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- 229910052581 Si3N4 Inorganic materials 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 2
- 229910052787 antimony Inorganic materials 0.000 description 2
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 description 2
- 229910052797 bismuth Inorganic materials 0.000 description 2
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 239000011651 chromium Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000000994 depressogenic effect Effects 0.000 description 2
- XKENYNILAAWPFQ-UHFFFAOYSA-N dioxido(oxo)germane;lead(2+) Chemical compound [Pb+2].[O-][Ge]([O-])=O XKENYNILAAWPFQ-UHFFFAOYSA-N 0.000 description 2
- NKZSPGSOXYXWQA-UHFFFAOYSA-N dioxido(oxo)titanium;lead(2+) Chemical compound [Pb+2].[O-][Ti]([O-])=O NKZSPGSOXYXWQA-UHFFFAOYSA-N 0.000 description 2
- 238000007598 dipping method Methods 0.000 description 2
- 230000006355 external stress Effects 0.000 description 2
- 238000007733 ion plating Methods 0.000 description 2
- 238000010884 ion-beam technique Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- HEPLMSKRHVKCAQ-UHFFFAOYSA-N lead nickel Chemical compound [Ni].[Pb] HEPLMSKRHVKCAQ-UHFFFAOYSA-N 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 239000011733 molybdenum Substances 0.000 description 2
- JTHNLKXLWOXOQK-UHFFFAOYSA-N n-propyl vinyl ketone Natural products CCCC(=O)C=C JTHNLKXLWOXOQK-UHFFFAOYSA-N 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 229910052758 niobium Inorganic materials 0.000 description 2
- 239000010955 niobium Substances 0.000 description 2
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 2
- ZBSCCQXBYNSKPV-UHFFFAOYSA-N oxolead;oxomagnesium;2,4,5-trioxa-1$l^{5},3$l^{5}-diniobabicyclo[1.1.1]pentane 1,3-dioxide Chemical compound [Mg]=O.[Pb]=O.[Pb]=O.[Pb]=O.O1[Nb]2(=O)O[Nb]1(=O)O2 ZBSCCQXBYNSKPV-UHFFFAOYSA-N 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 229920002037 poly(vinyl butyral) polymer Polymers 0.000 description 2
- 230000004043 responsiveness Effects 0.000 description 2
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 2
- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- 229920002050 silicone resin Polymers 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 239000003381 stabilizer Substances 0.000 description 2
- 229910052715 tantalum Inorganic materials 0.000 description 2
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 2
- 229920001187 thermosetting polymer Polymers 0.000 description 2
- 229910052718 tin Inorganic materials 0.000 description 2
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 2
- 229910052721 tungsten Inorganic materials 0.000 description 2
- 239000010937 tungsten Substances 0.000 description 2
- 238000007738 vacuum evaporation Methods 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 1
- 239000005751 Copper oxide Substances 0.000 description 1
- 229920001651 Cyanoacrylate Polymers 0.000 description 1
- UFHFLCQGNIYNRP-VVKOMZTBSA-N Dideuterium Chemical compound [2H][2H] UFHFLCQGNIYNRP-VVKOMZTBSA-N 0.000 description 1
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- 244000043261 Hevea brasiliensis Species 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- MWCLLHOVUTZFKS-UHFFFAOYSA-N Methyl cyanoacrylate Chemical compound COC(=O)C(=C)C#N MWCLLHOVUTZFKS-UHFFFAOYSA-N 0.000 description 1
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- YZCKVEUIGOORGS-NJFSPNSNSA-N Tritium Chemical compound [3H] YZCKVEUIGOORGS-NJFSPNSNSA-N 0.000 description 1
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 1
- IGDGIZKERQBUNG-UHFFFAOYSA-N [Cu].[Ba] Chemical compound [Cu].[Ba] IGDGIZKERQBUNG-UHFFFAOYSA-N 0.000 description 1
- VNSWULZVUKFJHK-UHFFFAOYSA-N [Sr].[Bi] Chemical compound [Sr].[Bi] VNSWULZVUKFJHK-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- JRPBQTZRNDNNOP-UHFFFAOYSA-N barium titanate Chemical compound [Ba+2].[Ba+2].[O-][Ti]([O-])([O-])[O-] JRPBQTZRNDNNOP-UHFFFAOYSA-N 0.000 description 1
- 229910002113 barium titanate Inorganic materials 0.000 description 1
- FSAJRXGMUISOIW-UHFFFAOYSA-N bismuth sodium Chemical compound [Na].[Bi] FSAJRXGMUISOIW-UHFFFAOYSA-N 0.000 description 1
- 239000005385 borate glass Substances 0.000 description 1
- 229910052810 boron oxide Inorganic materials 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 1
- 239000000292 calcium oxide Substances 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- ZMIGMASIKSOYAM-UHFFFAOYSA-N cerium Chemical compound [Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce] ZMIGMASIKSOYAM-UHFFFAOYSA-N 0.000 description 1
- 229910000420 cerium oxide Inorganic materials 0.000 description 1
- 239000011195 cermet Substances 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 229910000431 copper oxide Inorganic materials 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- JKWMSGQKBLHBQQ-UHFFFAOYSA-N diboron trioxide Chemical compound O=BOB=O JKWMSGQKBLHBQQ-UHFFFAOYSA-N 0.000 description 1
- CJXLIMFTIKVMQN-UHFFFAOYSA-N dimagnesium;oxygen(2-);tantalum(5+) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[Mg+2].[Mg+2].[Ta+5].[Ta+5] CJXLIMFTIKVMQN-UHFFFAOYSA-N 0.000 description 1
- 239000012777 electrically insulating material Substances 0.000 description 1
- 238000001962 electrophoresis Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000005038 ethylene vinyl acetate Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 1
- 239000011133 lead Substances 0.000 description 1
- JQJCSZOEVBFDKO-UHFFFAOYSA-N lead zinc Chemical compound [Zn].[Pb] JQJCSZOEVBFDKO-UHFFFAOYSA-N 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 229910001507 metal halide Inorganic materials 0.000 description 1
- 150000005309 metal halides Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229920003052 natural elastomer Polymers 0.000 description 1
- 229920001194 natural rubber Polymers 0.000 description 1
- -1 or the like Substances 0.000 description 1
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 description 1
- UZLYXNNZYFBAQO-UHFFFAOYSA-N oxygen(2-);ytterbium(3+) Chemical compound [O-2].[O-2].[O-2].[Yb+3].[Yb+3] UZLYXNNZYFBAQO-UHFFFAOYSA-N 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 239000005365 phosphate glass Substances 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 description 1
- 229920005668 polycarbonate resin Polymers 0.000 description 1
- 239000004431 polycarbonate resin Substances 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 239000009719 polyimide resin Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920005672 polyolefin resin Polymers 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- BITYAPCSNKJESK-UHFFFAOYSA-N potassiosodium Chemical compound [Na].[K] BITYAPCSNKJESK-UHFFFAOYSA-N 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 239000010948 rhodium Substances 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 238000005488 sandblasting Methods 0.000 description 1
- HYXGAEYDKFCVMU-UHFFFAOYSA-N scandium oxide Chemical compound O=[Sc]O[Sc]=O HYXGAEYDKFCVMU-UHFFFAOYSA-N 0.000 description 1
- 239000005368 silicate glass Substances 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- KKCBUQHMOMHUOY-UHFFFAOYSA-N sodium oxide Chemical compound [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 description 1
- 229910001948 sodium oxide Inorganic materials 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 1
- 229920003051 synthetic elastomer Polymers 0.000 description 1
- 239000005061 synthetic rubber Substances 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 239000011135 tin Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052722 tritium Inorganic materials 0.000 description 1
- 229910052724 xenon Inorganic materials 0.000 description 1
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 1
- 229910003454 ytterbium oxide Inorganic materials 0.000 description 1
- 229940075624 ytterbium oxide Drugs 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B3/00—Devices comprising flexible or deformable elements, e.g. comprising elastic tongues or membranes
- B81B3/0018—Structures acting upon the moving or flexible element for transforming energy into mechanical movement or vice versa, i.e. actuators, sensors, generators
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
- G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
- G02B26/0816—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements
- G02B26/0833—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD
- G02B26/0841—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD the reflecting element being moved or deformed by electrostatic means
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
- G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
- G02B26/0816—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements
- G02B26/0833—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD
- G02B26/0858—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD the reflecting means being moved or deformed by piezoelectric means
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R17/00—Piezoelectric transducers; Electrostrictive transducers
- H04R17/005—Piezoelectric transducers; Electrostrictive transducers using a piezoelectric polymer
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/20—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators
- H10N30/204—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators using bending displacement, e.g. unimorph, bimorph or multimorph cantilever or membrane benders
- H10N30/2047—Membrane type
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/80—Constructional details
- H10N30/87—Electrodes or interconnections, e.g. leads or terminals
- H10N30/872—Connection electrodes of multilayer piezoelectric or electrostrictive devices, e.g. external electrodes
- H10N30/874—Connection electrodes of multilayer piezoelectric or electrostrictive devices, e.g. external electrodes embedded within piezoelectric or electrostrictive material, e.g. via connections
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B2201/00—Specific applications of microelectromechanical systems
- B81B2201/03—Microengines and actuators
- B81B2201/032—Bimorph and unimorph actuators, e.g. piezo and thermo
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2201/00—Details of transducers, loudspeakers or microphones covered by H04R1/00 but not provided for in any of its subgroups
- H04R2201/003—Mems transducers or their use
Definitions
- the present invention relates to an actuator device which is applicable to a display device and which is also applicable to various applications including an optical modulator, a variable capacitor, etc.
- an actuator device having a plurality of actuators can be applied to a display device, and can also be applied to various applications including an optical modulator, a variable capacitor, etc. (see Japanese Laid-Open Patent Publication No. 11-339561, for example).
- the applicant of the present application has proposed a novel display device in order to achieve the following advantages:
- a clearance (gap) between an optical waveguide plate and a picture element assembly can easily be formed, and can be formed uniformly over all pixels.
- optical waveguide plate can be prevented from sticking to the picture element assembly, and the response speed can effectively be increased.
- the contact surface of the picture element assembly (the surface thereof contacting the optical waveguide plate) can smoothly be formed in order to introduce light efficiently into the picture element assembly when the picture element assembly contacts the optical waveguide plate.
- the luminance of pixels can be increased.
- a display device 200 has an optical waveguide plate 204 into which light 202 is introduced, an actuator substrate 208 facing one surface of the optical waveguide plate 204 and having as many actuators 206 as the number of pixels, picture element assemblies 210 formed on the actuators 206 of the actuator substrate 208 , and spacers 212 disposed between the optical waveguide plate 204 and the actuator substrate 208 in regions other than the picture element assemblies 210 (see, for example, Japanese Laid-Open Patent Publication No. 2003-161896 ).
- Light shield layers 218 are interposed between the optical waveguide plate 204 and the spacers 212 .
- one pixel may be made up of six actuators positioned in two rows and three columns. If one actuator 206 is defective in such a configuration, then a spot corresponding to that actuator 206 is displayed as a black or white dot regardless of an image displayed by the display device 200 , tending to cause a disadvantage to increase the image quality.
- the present invention has been made in view of the above drawbacks. It is an object of the present invention to provide an actuator device which, even when it has a defective actuator, can compensate for the displacement of the defective actuator with a normal actuator, has an increased yield, and has an increased effective area.
- Another object of the present invention is to provide an actuator device which, if applied as a display device, offers the following advantages:
- One pixel can be turned on and off by the displacement of a plurality of actuators, and a region of maximum displacement in one actuator can be utilized for increased luminance and contrast.
- An actuator device has a plurality of actuators arranged in a plane, and a plate member to which drive forces from the actuators are transmitted, each of the actuators having a vibrating section and a fixed section.
- the yield of the actuator devices is increased. Furthermore, the area of a portion that is displaced by the actuator, i.e., an effective area, can be increased. Particularly, three or more actuators should preferably be joined by the plate member. The probability of a failure is reduced, and the plate member can be controlled in displacement more stably. If the actuators are displaced in a z-axis direction and the plate member has its plane lying in a xy-plane direction, then three or more actuators may be arrayed in the x-axis direction, or two or more actuators may be arrayed in each of the x- and y-axis directions.
- the rigidity of the plate member should preferably be greater than the rigidity of the vibrating section.
- any faulty actuator can easily be displaced under external forces. Such defect compensation cannot be obtained by a laminated actuator, for example, which does not have the vibrating sections.
- the plate member may have concavities and convexities.
- the geometrical moment of inertia of the plate member is increased to increase the flexural rigidity of the plate member.
- the concavities and the convexities are effective in reducing the weight of the actuator device. Inasmuch as the inertial mass is reduced, the response speed of the actuators is increased.
- the concavities and the convexities may be provided as grooves, or may be arranged in a matrix or a staggered pattern.
- the concavities and the convexities may have an X shape, a circular shape, a grid shape, a striped shape, a comb-toothed shape, or the like as viewed in plan, or may have a dimple shape, a saw-toothed shape, a peak shape, a wedge shape, a rectangular shape, or the like, as viewed in cross section.
- the concavities and the convexities may be formed on both surfaces of the plate member or on one surface of the plate member.
- the plate member itself may be of a wavy shape.
- the actuators and the plate member may be connected to each other by displacement transmitters.
- the flexural rigidity of the plate member should preferably be 10 times the flexural rigidity of the vibrating sections or greater. This reduces the amount of flexing of the plate member. In this case, there is obtained a structure which is less susceptible to manufacturing irregularities with respect to the distance between the actuators and the size of the displacement transmitter (if the actuators and the plate member are connected to each other by the displacement transmitter).
- the drive forces of the actuators may be produced by a generation source which comprises a piezoelectric element, an electrostatic force, a magnetic force, an electromagnetic force, a spring, a wire, or the like.
- a piezoelectric element may have a unimorph structure, a bimorph structure, a monomorph structure, a structure in which a piezoelectric actuator is formed on the vibrating section, or a structure in which a piezoelectric actuator is formed on the vibrating section and the fixed section.
- an electrode may be disposed on a surface of the vibrating section which faces the fixed section and an electrode may be disposed on a surface of the fixed section which faces the vibrating section, and a voltage may be applied between the electrodes to generate an electrostatic force which displaces the vibrating section. Electrodes may be formed on the surface of the vibrating section, or an insulator may be interposed between the different electrodes to prevent them from contacting each other and being short-circuited, or the surfaces of the electrodes may be covered with an insulator.
- the distance between the vibrating sections and the plate member it is preferable for the distance between the vibrating sections and the plate member to remain substantially unchanged.
- the thickness (height) of the displacement transmitter be not essentially changed by the displacement of the actuators (not subject to compressive deformation, tensile deformation, and buckling deformation). In this case, compressive deformation and tensile deformation can be reduced by adding a filler to the displacement transmitter.
- the actuators should preferably have portions connected to the displacement transmitter and having a width smaller than the width of the vibrating section.
- the displacement of the vibrating section and forces produced thereby can reliably be transmitted to the plate member by the displacement transmitter.
- the displacement transmitter does not overlap the fixed section so as not to obstruct the displacement of the displacement transmitter, and it is preferable that the displacement transmitter be not too small with respect to the vibrating section so that the vibrating section and the first plate member are reliably fixed to each other.
- the displacement transmitter it is preferable for the displacement transmitter to connect the plate member and the vibrating section at a position including a portion of the vibrating section where the displacement is the greatest.
- the width of the displacement transmitter should be in the range from 5% to 99%, or preferably in the range from 30% to 90%, of the width of the vibrating section.
- the cross-sectional area of the displacement transmitter should be in the range from 0.5% to 99%, or preferably in the range from 10% to 90%, of the cross-sectional area of the vibrating section.
- the ratio of the height to width of the displacement transmitter i.e., the aspect ratio of the displacement transmitter, should be smaller than 1, or preferably smaller than 0.2.
- the plate member tends to flex without displacing the vibrating section of a faulty actuator, and the plate member includes a portion which is displaced and a portion which is not displaced. Therefore, such a rigidity setting is not preferable.
- the vibrating sections may be of a convex shape which is convex toward the plate member or concave toward the plate member.
- the vibrating sections of such a shape are more effective to increase the response of the actuators than if the vibrating sections are not of a convex shape (e.g., they are flat), and allow adjacent actuators to compensate for a displacement even if an actuator fails.
- the vibrating sections need to displace a large mass, and undergoes a larger load than if it were not for the plate member. Since the vibrating sections are of a convex shape, their drive forces become stronger to keep response at a higher level. The rigidity is increased to sufficiently bear the mass of the plate member that is applied to the vibrating sections.
- the first plate member driven by the adjacent actuators displaces the vibrating section. At this time, it is desirable that reactive forces from the vibrating section be small.
- the convex shape is considered to have such characteristics that it increases drive forces but prevents reactive forces from increasing when displaced by the plate member.
- the convex shape of the vibrating section may be formed in the longitudinal direction of a beam.
- the convex shape of the vibrating section may be formed in a direction parallel to the joint between the vibrating section and the fixed section.
- the vibrating section should preferably be of a wing shape (W shape) in the longitudinal direction of the beam. If the vibrating section has a wing shape, the width of the convex shape, i.e., the distance between valleys, should preferably be 1 ⁇ 3 of the beam length or greater. If the vibrating section is convex toward the plate member, then the vertex of the convex shape should preferably project toward the plate member beyond the height of the fixed section.
- the vibrating sections should preferably be of an arch shape or a wavy shape.
- the structure in which the vibrating sections are of a convex shape is particularly preferably used in an arrangement wherein the vibrating sections have both ends connected to the fixed section and an arrangement wherein the peripheral region of the vibrating sections is connected to the fixed section. If cavities are present below the vibrating sections, then the cavities may be filled with a liquid. In such a case, the peripheral region of the vibrating sections needs to be connected to the fixed section to prevent the liquid from leaking.
- the plate member In the event of a failure of an actuator, the plate member is displaced by a normal actuator, and the vibrating section of the faulty actuator is depressed by the displacement transmitter. If the vibrating section whose peripheral region is connected to the fixed section is of a flat cross-sectional shape, then forces tending to obstruct the displacement are liable to increase under the tension of the vibrating section which is kept taut. This is because the vibrating section is extended in its longitudinal direction for producing the above displacement. If the vibrating section is of an arch or wavy shape, then since the vibrating section itself has a larger length than the minimum distance between its joints to the fixed section, forces tending to obstruct the displacement are relatively weak when the vibrating section undergoes forces from the displacement transmitter.
- the vibrating section is of an arch shape
- the vibrating section should preferably have an arch shape that is convex toward the plate member.
- the vibrating section should preferably have an arch shape that is concave toward the plate member. If the actuator in which the vibrating section is convex toward the plate member is displaced toward the plate member, then the length of the vibrating section is increased and forces tending to obstruct the displacement thereof are increased. When the actuator in which the vibrating section is convex toward the plate member undergoes forces applied in a direction away from the plate member through the displacement transmitter, the actuator is displaced as the vibrating section flexes.
- the vibrating section With the vibrating section fixed at its both ends or peripheral region to the fixed section, since the rigidity of the vibrating section is not too high, the actuator device is highly effective to perform compensation for a failure. The degree of freedom for design is also increased.
- the vibrating section may also be fixed at one end to the fixed section.
- the height (or depth) of the convexity (or concavity) thereof toward the plate member should preferably be greater than the height (or depth) corresponding to the thickness of the vibrating section.
- the rigidity of the vibrating section needs to be not too small and should naturally be selected in view of the thickness, width, beam length, shape, material, etc. of the vibrating section.
- the convexity or concavity of the convex shape does not have to be formed in the central region of the vibrating section.
- Another actuator device has a plurality of cells arranged in a plane, each of the cells having a plurality of actuators arranged in a plane and a plate member to which drive forces from the actuators are transmitted, each of the actuators having a vibrating section and a fixed section.
- the cells may have the same size (the cells serve as unit cells) or may have different sizes.
- the rigidity of the plate member should preferably be greater than the rigidity of the vibrating section, as with the invention described above.
- the plate members of the cells may be connected to each other.
- the plate members should preferably be connected to each other by joints, the rigidity of all or some of the joints being smaller than the rigidity of the plate member.
- the rigidity of all or some of the joints may be made smaller than the rigidity of the plate member by using a material of less rigidity for the joints than the plate member, or making the joints thinner than the plate member or making the width of the joints smaller than the width of the plate member if the joints and the plate member are made of the same material.
- the above actuator device may further have gap forming members for forming gaps between the fixed sections and the plate members in the actuators, the joints interconnecting the plate members and the fixed sections being joined to each other by the gap forming members.
- the fixed section has different heights depending on the location, e.g., if the substrate has undulations (which are often unavoidable in the manufacturing process) when a plurality of actuators are to be formed on one substrate, the distance between the plate member disposed above the substrate and the fixed section varies depending on the location, possibly resulting in direct contact between the actuators and the plate member. In this case, the plate member is partly strained, tending to fail to operate the plate member as desired with the actuators.
- the gap forming members that are present on the fixed section do not give rise to the above problem even if the substrate has undulations because the distance between the plate member and the fixed section is maintained by the gap forming members.
- the actuators that are connected to the plate member have their displacement characteristics affected thereby.
- the degree of a change in the displacement characteristics is kept constant irrespective of the location, and the gap forming members are highly effective to prevent the displacement characteristics from varying.
- the thickness of the displacement transmitters is uniformized, the effect thereof on the displacement characteristics of the actuators is uniformized.
- the gap forming members can sufficiently be made effective by setting the gap forming members to an appropriate height.
- the actuator device may further have a second plate member, the second plate member having a plate surface facing a plate surface of the plate member (hereinafter referred to as first plate member). If it is assumed that the first plate member and the second plate member are disposed closely facing each other, then the gap forming members should preferably be disposed and connected such that the interval between the second plate member and the first plate member becomes a predetermined distance. In this case, the gap forming members should preferably be disposed and connected between the second plate member and the fixed section. If the joints of the first plate member and the fixed section are connected by the gap forming members, then the joints of the first plate member and the second plate member should preferably be connected by other gap forming members.
- the gap forming members should preferably be arranged such that they are associated with the respective cells. This is because the gap forming members can firmly be fixed, and the gap distance can accurately and reliably be established. If the effective areas of the cells are reduced due to the gap forming members associated with the respective cells, then for the purpose of increasing the effective area efficiency, a plurality of successive cells may be grouped into one large cell, and gap forming members may be associated with each large cell. Gap forming members may be provided on only the outer circumference of the actuator device.
- the gap forming members may be formed in a grid pattern so as to surround cells. Alternatively, the gap forming members may be formed in a striped pattern along confronting sides of cells. The gap forming members of a columnar shape and may be formed on the four corners of the four sides of the cells.
- the actuator device is constructed as a display device, i.e., if the second plate member comprises an optical waveguide plate into which light from a light source is introduced, and picture element assemblies are disposed on a surface of the plate member which faces the optical waveguide plate, wherein the actuator device serves as a display device for controlling light leaking from the optical waveguide plate with the picture element assemblies as they are brought into and out of contact with the optical waveguide plate, then the actuator device offers the following advantages:
- One pixel can be turned on and off by the displacement of a plurality of actuators, and a region of maximum displacement in one actuator can be utilized for increased luminance and contrast.
- variable capacitor may have its capacitance variable as the movable electrode is movable toward and/or away from the fixed electrode when the actuators are operated.
- the second plate member itself may serve as the fixed electrode of the variable capacitor or the plate member itself may serve as the movable electrode of the variable capacitor.
- the actuator device can serve as an interference optical modulator. Specifically, when input light is applied through the second plate member (transparent plate) to the plate member, light (first reflected light) reflected by the boundary between the reverse side of the transparent plate (which faces the plate member) and light (second reflected light) reflected by a light reflecting surface are emitted as output light. The first reflected light and the second reflected light interfere with each other, and the spectral distribution of the output light is adjusted by the displacement of the plate member and the second plate member.
- the actuator device thus functions as an interference optical modulator.
- the portion of the plate member which faces the second plate member may be turned into the light reflecting surface by constructing the surface of the plate member which faces the second plate member as a mirror surface, forming a light reflecting film on the region of the plate member which faces the second plate member, or forming a light reflecting film on that region with a base layer interposed therebetween.
- a layer such as a anti-reflection film or the like may be provided on both surfaces or one surface of the transparent plate.
- One pixel can be turned on and off by the displacement of a plurality of actuators, and a region of maximum displacement in one actuator can be utilized for increased luminance and contrast.
- FIG. 1 is a view showing an actuator device according to a first embodiment
- FIG. 2 is a cross-sectional view showing a structural example of an actuator
- FIG. 3 is a view showing an actuator device according to a second embodiment
- FIG. 4 is a view showing a preferred form of the actuator devices according to the first and second embodiments
- FIG. 5 is a view illustrative of the manner in which a displacement is compensated for when a second actuator of first and second actuators fails;
- FIG. 6 is a plan view showing an example of a structure for reducing the flexural rigidity of a vibrating section
- FIG. 7 is a plan view showing another example of a structure for reducing the flexural rigidity of a vibrating section
- FIG. 8 is a plan view of the structure shown in FIG. 7 ;
- FIG. 9 is a view showing a structure which employs electrostatic forces
- FIG. 10 is a plan view of an example of a structure for increasing the flexural rigidity of a first plate member
- FIG. 11 is a cross-sectional view taken along line XI-XI of FIG. 10 ;
- FIG. 12 is a plan view of another example of a structure for increasing the flexural rigidity of a first plate member
- FIG. 13 is a cross-sectional view showing an example of a structure in which the width of a portion of an actuator which is connected to a displacement transmitter is smaller than the width of a vibrating section;
- FIG. 14 is a cross-sectional view showing another example of a structure in which the width of a portion of an actuator which is connected to a displacement transmitter is smaller than the width of a vibrating section, and the width of a portion of a first plate member which is connected to the displacement transmitter is smaller than the width of the vibrating section;
- FIG. 15 is a cross-sectional view showing another example of a structure in which the width of a portion of a first plate member which is connected to a displacement transmitter is smaller than the width of a vibrating section;
- FIG. 16 is a view illustrative of operation of the structural example shown in FIG. 15 ;
- FIG. 17 is a cross-sectional view showing an example in which a vibrating section is of an arch shape
- FIG. 18 is a cross-sectional view showing an example in which a vibrating section is of a wavy shape
- FIG. 19 is a view illustrative of the manner in which a displacement is compensated for when a second actuator of first and second actuators fails;
- FIG. 20 is a perspective view showing a structural example in which a portion of a vibrating section has a wavy shape in the structure shown in FIG. 7 ;
- FIG. 21 is a plan view showing an example in which actuators are disposed at respective four corners of a first plate member
- FIG. 22 is a cross-sectional view taken along line XXII-XXII of FIG. 21 ;
- FIG. 23 is a plan view showing an example in which defect-compensating actuators are disposed in the structure shown in FIG. 21 ;
- FIG. 24 is a perspective view showing, with parts omitted from illustration, an example of joints interconnecting cells of a first plate member
- FIG. 25 is a perspective view showing, with parts omitted from illustration, another example of joints interconnecting cells of a first plate member
- FIG. 26A is a view showing a joint with a slit defined therein;
- FIG. 26B is a view showing a joint with a thinned portion
- FIG. 27 is a perspective view showing, with parts omitted from illustration, a first plate member having a plurality of recesses defined in a lower surface thereof, and joints with slits defined therein;
- FIG. 28 is a perspective view showing, with parts omitted from illustration, an example of a structure in which four successive cells are grouped into a large cell with spacers associated with the large cell;
- FIG. 29 is a perspective view showing, with parts omitted from illustration, an example (grid shape) of a structure of spacers;
- FIG. 30 is a perspective view showing, with parts omitted from illustration, another example (stripe shape No. 1 ) of a structure of spacers;
- FIG. 31 is a perspective view showing, with parts omitted from illustration, another example (stripe shape No. 2 ) of a structure of spacers;
- FIG. 32 is a perspective view showing, with parts omitted from illustration, another example (columnar shape) of a structure of spacers;
- FIG. 33 is a view showing an actuator device according to a third embodiment
- FIG. 34 is a view showing an actuator device according to a fourth embodiment
- FIG. 35 is a view showing a display device according to a first specific example
- FIG. 36 is an enlarged view showing an essential portion of the display device according to the first specific example, as viewed from an optical waveguide plate;
- FIG. 37 is a perspective view of a large-screen display device
- FIG. 38 is a cross-sectional view showing a structure of actuator
- FIG. 39A is a view showing a planar shape of a picture element assembly according to an inventive example.
- FIG. 39B is a view showing a planar shape of a picture element assembly according to a comparative example
- FIG. 40 is a view illustrative of the difference between the displacements of actuators per pixel according to the comparative example
- FIG. 41 is a view illustrative of the difference between the displacements of actuators per pixel according to the inventive example.
- FIG. 42 is a characteristic diagram showing luminance changes when a pixel is turned on and off, with respect to actuator defect ratios (the number of defective actuators/the number of actuators making up one pixel);
- FIG. 43 is a view of a joint plate with slits defined therein closely to spacers, as viewed from a reverse side of the joint plate;
- FIG. 44 is a view showing a display device according to a second specific example.
- FIG. 45 is a view showing a variable capacitor according to a specific example.
- FIG. 46 is a view showing a modification of the variable capacitor according to the specific example.
- FIG. 47 is a view showing an interference optical modulator according to a specific example.
- FIGS. 48A through 48C are cross-sectional views showing, with parts omitted from illustration, structural examples of mirror members
- FIG. 49 is a view showing an actuator device according to a fifth embodiment.
- FIG. 50 is a view showing a first modification of the actuator device according to the fifth embodiment.
- FIG. 51 is a view showing a second modification of the actuator device according to the fifth embodiment.
- FIG. 52 is a view showing a conventional display device.
- FIG. 53 is a plan view of the conventional display device as viewed from an optical waveguide plate thereof.
- Embodiments of actuator devices according to the present invention will be described below with reference to FIGS. 1 through 51 .
- an actuator device 10 A has a drive section 16 including a plurality of actuators 14 arranged in a plane on a substrate 12 , and a first plate member 18 to which drive forces from the actuators 14 of the drive section 16 are transmitted.
- a plurality of spacers 24 are disposed between the first plate member 18 and the substrate 12 , forming m cells 15 .
- N actuators 14 are assigned to each of the cells 15 .
- Each of the cells 15 may have the same size (the cells serve as unit cells) or may have different sizes.
- Each of the actuators 14 comprises a cavity 64 , a vibrating section 66 , and a fixed section 68 formed in the substrate 12 .
- a portion where the cavity 64 is defined is thin, and the other portion is thick.
- the thin portion is of a structure easily vibratable under external stresses and functions as the vibrating section 66 .
- the portion other than the cavity 64 is thick and functions as the fixed section 68 supporting the vibrating section 66 .
- a displacement transmitter 76 for transmitting displacement of the actuator 14 to the first plate member 18 is interposed between the actuator 14 and the first plate member 18 .
- the actuator 14 has, in addition to the vibrating section 66 and the fixed section 68 , an actuator body 75 comprising a piezoelectric/electrostrictive layer 72 directly formed on the vibrating section 66 , and a pair of electrodes 74 a, 74 b formed on upper and lower surfaces of the piezoelectric/electrostrictive layer 72 .
- the electrodes 74 a, 74 b may be formed on the upper and lower sides of the piezoelectric/electrostrictive layer 72 , as shown in FIG. 2 , or on only one side thereof, or on only the upper side of the piezoelectric/electrostrictive layer 72 .
- the electrodes 74 a, 74 b may be of a planar shape having a number of comb teeth complementarily facing each other, or may be of a swirling or branched shape as disclosed in Japanese Laid-Open Patent Publication No. 10-78549 and Japanese Laid-Open Patent Publication No. 2001-324961.
- the actuator body 75 of the actuator 14 is omitted from illustration for the sake of brevity.
- the drive forces of the actuators 14 may be produced by a generation source which comprises a piezoelectric element, an electrostatic force, a magnetic force, an electromagnetic force, a spring, a wire, or the like.
- a piezoelectric element may have a unimorph structure, a bimorph structure, a monomorph structure, a structure in which a piezoelectric actuator is formed on the vibrating section 66 , or a structure in which a piezoelectric actuator is formed on the vibrating section 66 and the fixed section 68 .
- an electrode may be disposed on a surface of the vibrating section 66 which faces the fixed section 68 and an electrode may be disposed on a surface of the fixed section 68 which faces the vibrating section 66 , and a voltage may be applied between the electrodes to generate an electrostatic force which displaces the vibrating section 66 (see FIG. 9 ). Electrodes may be formed on the surface of the vibrating section 66 , or an insulator may be interposed between the different electrodes to prevent them from contacting each other and being short-circuited, or the surfaces of the electrodes may be covered with an insulator.
- an actuator device 10 B according to a second embodiment is of substantially the same structure as the actuator device 10 A according to the first embodiment, but differs therefrom in that it has separate first plate members 18 in alignment with the respective m cells 15 .
- the first plate member 18 should preferably have a rigidity greater than the rigidity of the vibrating sections 66 of the actuators 14 .
- FIG. 4 shows a structure in which a single first plate member 18 is connected to two actuators (a first actuator 14 a and a second actuator 14 b ) by respective displacement transmitters 76 .
- holes 170 may be defined in corresponding portions of the fixed section 68 between the displacement transmitters 76 of adjacent cells 15 .
- FIG. 5 shows a state in which the second actuator 14 b fails and the first actuator 14 a is displaced to displace the first plate member 18 downwardly.
- the first plate member 18 tends to lower the second actuator 14 b downwardly, but the second actuator 14 b moves back a distance w 1 , due to a reactive force from the vibrating section 66 of the second actuator 14 b.
- the first plate member 18 flexes the distance w 1
- w 1 / w 2 16 ⁇ ( L 1 / L 2 ) 3 ⁇ ( E 2 I 2 / E 1 I 1 ) (3)
- the ratio w 1 /w 2 is smaller, the displacement of the faulty second actuator 14 b can be better compensated for. That is, as the flexural rigidity E 1 I 1 of the first plate member 18 is greater than the flexural rigidity E 2 I 2 of the vibrating sections 66 of the first and second actuators 14 a , 14 b , the ratio w 1 /w 2 is smaller, resulting in a greater ability to compensate for the displacement of the second actuator 14 b.
- the vibrating sections 66 may extend in a cantilevered fashion from the fixed section 68 into the cavity 64 .
- w 1 PL 1 3 /(3 E 1 I 1 )
- w 2 PL 2 3 /(3 E 2 I 2 ) (5) cantilevered
- w 1 / w 2 ( L 1 / L 2 ) 3 ⁇ ( E 2 I 2 / E 1 I 1 ) (6)
- FIGS. 7 and 8 Since the structure shown in FIGS. 7 and 8 is capable of reducing L 1 /L 2 , it is advantageous in that it can reduce the ratio w 1 /w 2 .
- an electrode 172 is formed on the lower surface of the vibrating section 66 of the first actuator 14 a
- an electrode 174 is formed on the lower surface of the vibrating section 66 of the second actuator 14 b
- an electrode 176 facing the electrode 172 and the electrode 174 is formed on the bottom of the cavity 64 , so that the first and second actuators 14 a, 14 b can be displaced under electrostatic forces.
- a voltage is applied between the electrode 172 and the electrode 176 to displace the first actuator 14 a downwardly, causing the first plate member 18 and the second actuator 14 b to be displaced downwardly.
- the flexural rigidity of the first plate member 18 may be increased by providing a plurality of grooves 178 in the lower surface of the first plate member 18 .
- the grooves 178 are formed (extend) in a direction in which the actuators 14 are arrayed.
- the grooves 178 have a depth which is 10% or more, preferably 30% or more, of the thickness of the first plate member 18 .
- the flexural rigidity of the first plate member 18 may also be increased by providing a matrix or a staggered pattern of concavities 180 or convexities 182 . If the actuators 14 are displaced in a z-axis direction and the first plate member 18 has its plane lying in a xy-plane direction, then the above arrangement is suitable for increasing the flexural rigidity of the first plate member 18 in the case where two or more actuators 14 are arrayed in each of x- and y-axis directions.
- the structure shown in FIG. 12 is effective in increasing geometrical moments of inertia in the x- and y-axis directions, thus increasing the flexural rigidity in all directions.
- the depth of the concavities 180 and the height of the convexities 182 are 10% or more, or preferably 30% or more, of the thickness of the first plate member 18 .
- the concavities 180 and the convexities 182 may have an X shape, a circular shape, a grid shape, a striped shape, a comb-toothed shape, or the like as viewed in plan, or may have a dimple shape, a saw-toothed shape, a peak shape, a wedge shape, a rectangular shape, or the like, as viewed in cross section.
- the concavities 180 and the convexities 182 may be formed on both surfaces of the first plate member 18 or on one surface of the first plate member 18 .
- the first plate member 18 itself may be of a wavy shape.
- the flexural rigidity of the first plate member 18 may be made greater than the flexural rigidity of the vibrating sections 66 in terms of material and thickness.
- the vibrating sections 66 are made of zirconium oxide, then the Young's modulus thereof is 245.2 GPa, and if the first plate member 18 is made of stainless steel (e.g., SUS304), then the Young's modulus thereof is 193.0 GPa.
- the cross section has a rectangular shape, then the geometrical moment of inertia is proportional to the cube of the thickness.
- the width of a portion of the actuator 14 which is joined to the displacement transmitter 76 is smaller than the width of the vibrating section 66 .
- Specific structural examples of this form are shown in FIG. 13 or 14 , for example.
- the displacement transmitter 76 is formed continuously over at least two actuators 14 a, 14 b, and has a substantially flat upper surface and a lower surface having convexities 184 aligned respectively with the actuators 14 a, 14 b.
- a contact width d 1 of the displacement transmitter 76 with respect to the first plate member 18 a contact width d 2 of the displacement transmitter 76 with respect to the actuator (the vibrating section 66 ), and a width d 3 of the vibrating section 66 satisfy d 1 >d 3 >d 2 . If the vibrating section 66 is regarded as a beam, then the width referred to above represents a value corresponding to the length of the beam.
- the displacement transmitters 76 are formed separately from each other in alignment with the respective actuators 14 a, 14 b.
- the width of a portion of the first plate member 18 which is joined to the displacement transmitter 76 is smaller than the width of the vibrating section 66 .
- Specific structural examples of this form are shown in FIG. 14 or 15 , for example.
- the displacement transmitter 76 is formed continuously over at least two actuators 14 a, 14 b, and has a substantially flat lower surface and an upper surface having convexities 186 aligned respectively with the actuators 14 a, 14 b.
- the structure shown in FIG. 10 has been described above, and will not be described below.
- the actuator devices 10 A, 10 B according to the first and second embodiments even when some of the actuators 14 become defective, their displacement can be compensated for by the normal actuators 14 . Therefore, the yield of the actuator devices is increased. Furthermore, the area of a portion that is displaced by the actuator 14 , i.e., an effective area, can be increased.
- the rigidity of the first plate member 18 is greater than the rigidity of the vibrating sections 66 of the actuators 14 , even when one actuator 14 fails due to cracking or wire breakage, the first plate member 18 is displaced when another actuator 14 is displaced, producing forces to displace the vibrating section 66 of the faulty actuator 14 . Consequently, even in the event of a failure of one actuator 14 , the displacement of the entire first plate member 18 is not affected thereby, making it possible to compensate for the faulty region. Since the actuators 14 have the vibrating sections 66 , any faulty actuator can easily be displaced under external forces. Such defect compensation cannot be obtained by a laminated actuator, for example, which does not have the vibrating sections 66 .
- the flexural rigidity of the first plate member 18 should be 10 times the flexural rigidity of the vibrating sections 66 or greater. This reduces the amount of flexing of the first plate member 18 . In this case, there is obtained a structure which is less susceptible to manufacturing irregularities with respect to the distance between the actuators 14 and the size of the displacement transmitter 76 .
- the first plate member 18 has the grooves 178 , the concavities 180 , and the convexities 182 , the geometrical moment of inertia of the first plate member 18 can be increased, and the flexural rigidity of the first plate member 18 can be increased. Because the rigidity can be increased with a small amount of material, they are effective in reducing the weight of the actuator device. Inasmuch as the inertial mass is reduced, the response speed of the actuators is increased.
- the distance between the vibrating sections 66 and the first plate member 18 it is preferable for the distance between the vibrating sections 66 and the first plate member 18 to remain substantially unchanged.
- the displacement transmitter 76 is interposed between the vibrating sections 66 and the first plate member 18 , then it is preferable that the thickness (height) of the displacement transmitter 76 be not essentially changed by the displacement of the actuators 14 (not subject to compressive deformation, tensile deformation, and buckling deformation). In this case, compressive deformation and tensile deformation can be reduced by adding a filler to the displacement transmitter 76 .
- the actuator device may be arranged not to obstruct the displacement of the displacement transmitter 76 , and with the forms shown in FIGS. 13 and 14 , the actuator device may be arranged such that the displacement transmitter 76 does not overlap the fixed section 68 .
- the displacement transmitter 76 should preferably be not too small with respect to the vibrating section 66 so that the vibrating section 66 and the first plate member 18 are reliably fixed to each other.
- the displacement and generated forces differ depending on the location of the vibrating section 66 , even if the joint between the vibrating section 66 and the displacement transmitter 76 does not include a portion of the vibrating section 66 which causes the largest displacement, optimum values can be obtained from generated forces and a required amount of displacement.
- the width of the displacement transmitter 76 should be in the range from 5% to 99%, or preferably in the range from 30% to 90%, of the width of the vibrating section 66 .
- the cross-sectional area of the displacement transmitter 76 should be in the range from 0.5% to 99%, or preferably in the range from 10% to 90%, of the cross-sectional area of the vibrating section 66 .
- the ratio of the height to width of the displacement transmitter 76 i.e., the aspect ratio of the displacement transmitter 76 , should be smaller than 1, or preferably smaller than 0.2.
- the first plate member 18 tends to flex without displacing the vibrating section 66 of a faulty actuator 14 , and the first plate member 18 includes a portion which is displaced and a portion which is not displaced. Therefore, such a rigidity setting is not preferable.
- the vibrating sections 66 are flat. However, as shown in FIG. 17A , the vibrating sections 66 may be of an arch shape, or as shown in FIG. 18 , the vibrating sections 66 may be of a wavy shape. In the examples shown in FIGS. 17A and 18 , the vibrating sections 66 are convex toward the first plate member 18 . The vibrating sections 66 that are convex toward the first plate member 18 are more effective to increase the response of the actuators 14 than if the vibrating sections 66 are not of a convex shape (e.g., they are flat), and allow adjacent actuators 14 to compensate for displacement even if an actuator 14 fails.
- the vibrating sections 66 need to displace a large mass, and undergoes a larger load than if it were not for the first plate member 18 . Since the vibrating sections 66 are of a convex shape, their drive forces become stronger to keep response at a higher level. The rigidity is increased to sufficiently bear the mass of the first plate member 18 that is applied to the vibrating sections 66 .
- the first plate member 18 driven by the adjacent actuators 14 displaces the vibrating section 66 .
- the convex shape is considered to have such characteristics that it increases drive forces but prevents reactive forces from increasing when displaced by the first plate member 18 .
- the structure in which the vibrating sections 66 are of a convex shape is particularly preferably used in an arrangement wherein the vibrating sections 66 have both ends connected to the fixed section 68 and an arrangement wherein the peripheral region of the vibrating sections is connected to the fixed section 68 . If cavities are present below the vibrating sections 66 , then the cavities may be filled with a liquid. In such a case, the peripheral region of the vibrating sections 66 needs to be connected to the fixed section 68 to prevent the liquid from leaking.
- the first plate member 18 is displaced by a normal actuator 14 , and the vibrating section 66 of the faulty actuator 14 is depressed by the displacement transmitter 76 . If the vibrating section 66 whose peripheral region is connected to the fixed section 68 is of a flat cross-sectional shape, then forces tending to obstruct the displacement are liable to increase under the tension of the vibrating section 66 which is kept taut. This is because the vibrating section 66 is extended in its longitudinal direction for producing the above displacement.
- the vibrating section 66 is of an arch or wavy shape, then since the vibrating section 66 itself has a larger length than the minimum distance between its joints to the fixed section 68 , forces tending to obstruct the displacement are relatively weak when the vibrating section 66 undergoes forces from the displacement transmitter 76 .
- the vibrating section 66 is of an arch shape, then when the actuator 14 is displaced under drive forces in a direction away from the first plate member 18 , the vibrating section 66 should preferably have an arch shape that is convex toward the first plate member 18 . When the actuator 14 is displaced under drive forces in a direction toward the first plate member 18 , the vibrating section 66 should preferably have an arch shape that is concave toward the first plate member 18 .
- the actuator 14 in which the vibrating section 66 is convex toward the first plate member 18 is displaced toward the first plate member 18 , then the length of the vibrating section 66 is increased and forces tending to obstruct the displacement thereof are increased.
- the actuator 14 in which the vibrating section 66 is convex toward the first plate member 18 undergoes forces applied in a direction away from the first plate member 18 through the displacement transmitter 76 , the actuator 14 is displaced as the vibrating section 66 flexes.
- the vibrating section 66 With the vibrating section 66 fixed at its both ends or peripheral region to the fixed section 68 , since the rigidity of the vibrating section 66 is not too high, the actuator device is highly effective to perform compensation for a failure. The degree of freedom for design is also increased.
- the vibrating section 66 may also be fixed at one end to the fixed section 68 .
- the height (or depth) of the convexity (or concavity) thereof toward the first plate member 18 should preferably be greater than the height (or depth) corresponding to the thickness of the vibrating section 66 .
- the rigidity of the vibrating section 66 needs to be not too small and should naturally be selected in view of the thickness, width, beam length, shape, material, etc. of the vibrating section 66 .
- the convexity or concavity of the convex shape does not have to be formed in the central region of the vibrating section 66 .
- the convex shape of the vibrating section 66 may be formed in the longitudinal direction of the beam.
- the convex shape of the vibrating section 66 may be formed in a direction parallel to the joint between the vibrating section 66 and the fixed section 68 .
- the vibrating section 66 should preferably be of a wing shape (W shape) in the longitudinal direction of the beam.
- W shape wing shape
- the arrows A indicate that the vibrating section 66 is deformed in a convex shape.
- the width of the convex shape i.e., the distance between valleys, should preferably be 1 ⁇ 3 of the beam length or greater. If the vibrating section 66 is convex toward the first plate member 18 , then the vertex of the convex shape should preferably project toward the first plate member 18 beyond the height of the fixed section 68 .
- one first plate member 18 may be provided in combination with four actuators 14 arranged in a matrix.
- the actuators 14 should preferably be disposed at the respective four corners of the first plate member 18 .
- actuators 14 may be disposed at the respective four corners of the first plate member 18 , and defect-compensating actuators 14 e may be disposed on the diagonal lines of the first plate member 18 adjacent to the respective actuators 14 for greatly increased reliability.
- the actuator devices 10 A, 10 B according to the first and second embodiments have a plurality of cells 15 arranged in a plane.
- the first plate member of the actuator device 10 A according to the first embodiment has interconnected portions corresponding to the respective cells 15 , as shown in FIGS. 24 and 25 .
- the rigidity of all or some of joints 190 interconnecting the cells 15 is smaller than the rigidity of portions 192 (hereinafter referred to as cell portions) of the first plate member 18 which correspond to the respective cells 15 .
- the rigidity of all or some of the joints 190 of the first plate member 18 may be made smaller than the rigidity of the cell portions 192 by forming slits 194 or the like in the joints 190 to make the width (2 ⁇ D 2 ) of the joints 190 smaller than the width D 1 of the cell portions 192 , as shown in FIG. 26A , or by making portions 196 of the joints 190 thinner than the cell portions 192 , as shown in FIG. 26B .
- slits 194 are formed in portions of the first plate member 18 which correspond to the spacers 24 (spacer portions 220 ), and the cell portions 192 and the spacer portions 220 are joined by narrow arms 222 .
- a plurality of vertical rule portions 224 and a plurality of horizontal rule portions 226 which extend respectively vertically and horizontally along the array of spacers 24 are joined by the spacer portions 220 , and the horizontal rule portions 226 and the cell portions 192 are joined by narrow arms 222 .
- slits 194 A along the vertical rule portions 224 and slits 194 B along the horizontal rule portions 226 are formed in the first plate member 18 .
- one surface (e.g., lower surface) of the first plate member 18 is half-etched to a depth which is half the thickness of the first plate member 18 , thereby forming a plurality of recesses 180 in the cell portions 192 .
- the joints 190 between the cell portions 192 and portions where slits are to be formed are also half-etched to form recesses 198 .
- portions where slits are to be formed on the opposite surface (e.g., upper surface) are etched to form holes in the portions where slits are to be formed, thereby forming slits 194 .
- each of the cell portions 192 has its geometrical moment of inertia increased by the recesses 180 , and hence has increased flexural rigidity.
- the joints 190 have their thickness reduced to about half by the recesses 198 , and also have their width reduced by the slits 194 . Therefore, the flexural rigidity of the joints 190 is smaller than the cell portions 192 .
- the actuator device 10 A as shown in FIG. 24 , for example, as the joints 190 of the first plate member 18 and the fixed sections 68 (see FIG. 1 ) are joined by the spacers 24 , the distance between the cell portions 192 of the first plate member 18 and the fixed sections 68 can be established accurately and reliably.
- the spacers 24 that are present between the substrate 12 and the joints 190 of the first plate member 18 offer the following advantages:
- the substrate 12 has different heights depending on the location, e.g., if the substrate 12 has undulations (which are often unavoidable in the manufacturing process) when a plurality of actuators 14 are to be formed on one substrate 12 , the distance between the substrate 12 and the first plate member 18 disposed above the substrate 12 varies depending on the location, possibly resulting in direct contact between the actuators 14 and the first plate member 18 . In this case, the first plate member 18 is partly strained, tending to fail to operate the first plate member 18 as desired with the actuators 14 .
- the spacers 24 that are present between the substrate 12 and the joints 190 of the first plate member 18 do not give rise to the above problem even if the substrate 12 has undulations because the distance between the first plate member 18 and the substrate 12 is maintained by the spacers 24 .
- the actuators 14 that are connected to the first plate member 18 have their displacement characteristics affected thereby.
- the degree of a change in the displacement characteristics of the actuators 14 is kept constant irrespective of the location, and the spacers 24 are highly effective to prevent the displacement characteristics from varying.
- the thickness of the connectors e.g., the displacement transmitters 76
- the effect thereof on the displacement characteristics of the actuators 14 is uniformized.
- the spacers 24 can sufficiently be made effective by setting the spacers 24 to an appropriate height.
- the spacers 24 should be arranged such that they are associated with the respective cells 15 , as shown in FIG. 24 . This is because the spacers 24 can firmly be fixed, and the distance between the cell portions 192 and the fixed sections 68 can accurately and reliably be established. If the effective areas of the cell portions 192 are reduced due to the spacers 24 associated with the respective cells 15 , then for the purpose of increasing the effective area efficiency, as shown in FIG. 28 , four successive cells 15 are grouped into one large cell 200 , and spacers 24 may be associated with each large cell 200 . Spacers 24 may be provided on only the outer circumference of the actuator device 10 A.
- spacers 24 may be formed in a grid pattern so as to surround cells 15 .
- spacers 24 may be formed in a striped pattern along confronting sides of cells 15 .
- columnar spacers 24 may be disposed on the four corners of cells 15 , or as shown in FIG. 32 , columnar spacers 24 may be disposed on the four sides of cells 15 .
- an actuator device 10 C according to a third embodiment is of substantially the same structure as the actuator device according to the first embodiment, but differs therefrom in that it has a second plate member 20 disposed facing the first plate member 18 .
- a plurality of spacers 22 are formed between the first plate member 18 and the second plate member 20 , forming m cells 15 , for example.
- an actuator device 10 D according to a fourth embodiment is of substantially the same structure as the actuator device 10 B according to the second embodiment, but differs therefrom in that the first plate member 18 is divided into segments corresponding to the m cells 15 .
- a plurality of spacers 26 are interposed between the second plate member 20 and the substrate 12 in gaps between adjacent ones of the first plate members 18 .
- the actuator devices 10 A through 10 D according to the first through fourth embodiments described above are applicable to a display device, and also applicable to a variable capacitor, an optical modulator, or the like.
- Display devices 30 A, 30 B according to first and second specific examples, to which the actuator devices 10 C, 10 D according to the third and fourth embodiments are applied, will be described below with reference to FIGS. 35 through 44 .
- the display device 30 A has a drive section 36 including a plurality of actuators 34 arranged in a plane (e.g., a matrix or staggered pattern) on an actuator substrate 32 , a single optical waveguide plate 38 which is disposed facing the actuator substrate 32 and into which light 33 from a light source is introduced from an end face thereof, and a single joint plate 40 which is disposed between the actuator substrate 32 and the optical waveguide plate 38 and to which drive forces from the actuators 34 of the drive section 36 are transmitted.
- a drive section 36 including a plurality of actuators 34 arranged in a plane (e.g., a matrix or staggered pattern) on an actuator substrate 32 , a single optical waveguide plate 38 which is disposed facing the actuator substrate 32 and into which light 33 from a light source is introduced from an end face thereof, and a single joint plate 40 which is disposed between the actuator substrate 32 and the optical waveguide plate 38 and to which drive forces from the actuators 34 of the drive section 36 are transmitted.
- a plurality of spacers 42 are formed between the actuator substrate 32 and the joint plate 40 surrounding cells 50 which form respective pixels (pixel forming zones).
- a plurality of spacers 44 are also formed between the joint plate 40 and the optical waveguide plate 38 surrounding the cells 50 .
- Each of the cells 50 is separated in a rectangular shape, for example, by plural spacers 42 , 44 , and has a region including six actuators 34 (in two rows and three columns), for example.
- One picture element assembly 52 is formed on the joint plate 40 in association with each cell 50 .
- one picture element assembly 52 on the joint plate 40 is assigned to six actuators 34 on the actuator substrate 32 .
- a plurality of display devices 30 A according to the first specific example are arranged in a matrix on the back of a single light guide plate 60 , as shown in FIG. 37 , thus providing a single large-screen display device 62 .
- the large-screen display device 62 has a matrix of display devices 30 A, five in a horizontal direction and four in a vertical direction, on the back of the light guide plate 60 , such that 640 pixels are arrayed in the horizontal direction and 480 pixels are arrayed in the vertical direction, in order to comply with VGA (Video Graphics Array) standards, for example.
- VGA Video Graphics Array
- the light guide plate 60 comprises a glass plate, an acrylic plate, or the like whose light transmittance is large and uniform in the visible range.
- the displace devices 30 A are connected by wire bonding, soldering, end-face connectors, reverse-side connectors, etc. for supplying signals therebetween.
- the light guide plate 60 and the optical waveguide plates 38 of the display devices 30 A should preferably have similar refractive indexes. If the light guide plate 60 and the optical waveguide plates 38 are bonded to each other, then a transparent adhesive or liquid may be used to bond them together. Such a transparent adhesive or liquid should preferably have a uniform and high light transmittance in the visible range, like the light guide plate 60 and the optical waveguide plates 38 , and a refractive index close to those of the light guide plate 60 and the optical waveguide plates 38 for achieving screen brightness.
- the surfaces of the optical waveguide plates 38 of the display devices 30 A are bonded to the light guide plate 60 , making up the large-screen display device 62 .
- the optical waveguide plates 38 may be dispensed with, the end faces of the spacers 44 (see FIG. 35 ) may be directly bonded to the light guide plate 60 , making up the large-screen display device 62 .
- the actuator substrate 32 of the display device 30 A has cavities 64 defined therein at positions in alignment with the respective actuators 34 and forming vibrating sections 66 to be described later.
- the cavities 64 communicate with the exterior through small-diameter through holes (not shown) defined in the other end of the actuator substrate 32 .
- portions where the cavities 64 are defined are thin, and the other portions are thick.
- the thin portions are of a structure easily vibratable under external stresses and function as the vibrating sections 66 .
- the portions other than the cavities 64 are thick and function as fixed sections 68 supporting the vibrating sections 66 .
- the actuator substrate 32 comprises a laminated assembly of a substrate layer 32 A as a lowermost layer, a spacer layer 32 B as an intermediate layer, and a thin layer 32 C as an uppermost layer, and can be recognized as a unitary structural body in which the cavity 64 is defined in the portion of the spacer layer 32 B that corresponds to the actuator 34 .
- the substrate layer 32 A functions as a stiffening substrate and also as a wiring substrate.
- the actuator substrate 32 may be integrally sintered or may subsequently be added.
- the substrate layer 32 A, the spacer layer 32 B, and the thin layer 32 C may be made of a material which is highly resistant to heat, highly strong, and highly tough, e.g., stabilized zirconium oxide, partially stabilized zirconium oxide, aluminum oxide, magnesium oxide, titanium oxide, spinel, mullite, or the like.
- the substrate layer 32 A, the spacer layer 32 B, and the thin layer 32 C may be made of one material or different materials.
- the thin layer 32 C has a thickness of 50 ⁇ m or preferably in the range from 3 ⁇ m to 20 ⁇ m for allowing the actuator 34 to be displaced largely.
- the spacer layer 32 B may be present as providing the cavities 64 in the actuator substrate 32 , and is not limited to any thickness. However, the thickness of the spacer layer 32 B may be determined depending on the purpose for which the cavities 64 are used. It is preferable that the spacer layer 32 B do not have a thickness greater than necessary for the actuator 34 to function, and should be thin. That is, the thickness of the spacer layer 32 B should preferably be as large as the displacement of the actuator 34 .
- the flexing of the thin portion (the vibrating section 66 ) is limited by the substrate layer 32 A which is close thereto in the direction in which the thin portion flexes, and the thin portion is prevented from being broken under unintended external forces applied thereto. It is possible to stabilize the displacement of the actuator 34 at a particular value by using the ability of the substrate layer 32 A to limit the flexing of the thin portion.
- the thickness of the actuator substrate 32 itself and its flexural rigidity can be reduced by thinning the spacer layer 32 B, when the actuator substrate 32 is bonded and fixed to a separate body, buckling or the like of the actuator substrate 32 with respect to the separate body (e.g., the optical waveguide plate 38 or the joint plate 40 ) can effectively be corrected for increased bonding and fixing reliability.
- the thickness of the spacer layer 32 B should preferably in the range from 3 ⁇ m to 50 ⁇ m and more preferably in the range from 3 ⁇ m to 20 ⁇ m.
- the thickness of the substrate layer 32 A is equal to or greater than 50 ⁇ m, preferably in the range from 80 ⁇ m to 300 ⁇ m, for the purpose of reinforcing the entire actuator substrate 32 .
- FIG. 35 shows a structure in which light shield layers 70 are disposed between the spacers 44 interposed between the optical waveguide plate 38 and the joint plate 40 and the optical waveguide plate 38 .
- the actuator 34 has, in addition to the vibrating section 66 and the fixed section 68 , an actuator body 75 comprising a piezoelectric/electrostrictive layer 72 directly formed on the vibrating section 66 , and a pair of electrodes 74 a, 74 b formed on upper and lower surfaces of the piezoelectric/electrostrictive layer 72 .
- the electrodes 74 a, 74 b may be formed on the upper and lower sides of the piezoelectric/electrostrictive layer 72 , as shown in FIG. 38 , or on only one side thereof, or on only the upper side of the piezoelectric/electrostrictive layer 72 .
- the electrodes 74 a, 74 b may be of a planar shape having a number of comb teeth complementarily facing each other, or may be of a swirling or branched shape as disclosed in Japanese Laid-Open Patent Publication No. 10-78549 and Japanese Laid-Open Patent Publication No. 2001-324961.
- the electrodes 74 a, 74 b are made of a metal such as aluminum, titanium, chromium, iron, cobalt, nickel, copper, zinc, niobium, molybdenum, ruthenium, palladium, rhodium, silver, tin, tantalum, tungsten, iridium, platinum, gold, lead, or the like, or an alloy of at least two of these metals.
- a metal such as aluminum, titanium, chromium, iron, cobalt, nickel, copper, zinc, niobium, molybdenum, ruthenium, palladium, rhodium, silver, tin, tantalum, tungsten, iridium, platinum, gold, lead, or the like, or an alloy of at least two of these metals.
- the electrodes 74 a, 74 b may be made of an electrically conductive material such as a cermet containing the above metal or alloy to which there is added aluminum oxide, titanium oxide, zirconium oxide, cerium oxide, copper oxide, or the like, or containing the metal or alloy in which the material of the actuator substrate 32 and/or the same material as a piezoelectric/ electrostrictive material to be described below is dispersed.
- an electrically conductive material such as a cermet containing the above metal or alloy to which there is added aluminum oxide, titanium oxide, zirconium oxide, cerium oxide, copper oxide, or the like, or containing the metal or alloy in which the material of the actuator substrate 32 and/or the same material as a piezoelectric/ electrostrictive material to be described below is dispersed.
- the electrodes 74 a, 74 b may be formed on the actuator substrate 32 by a film forming process such as photolithography, screen printing, dipping, coating, electrophoresis, ion beam process, sputtering, vacuum evaporation, ion plating, chemical vapor deposition (CVD), plating, etc.
- a film forming process such as photolithography, screen printing, dipping, coating, electrophoresis, ion beam process, sputtering, vacuum evaporation, ion plating, chemical vapor deposition (CVD), plating, etc.
- Preferred materials that can be used for the piezoelectric/electrostrictive material include lead zirconate, lead manganese tungstenate, bismuth sodium titanate, bismuth ferrate, sodium potassium niobate, bismuth strontium tantalate, lead magnesium niobate, lead nickel niobate, lead zinc niobate, lead manganese niobate, lead magnesium tantalate, lead nickel tantalate, lead antimony tinate, lead titanate, barium titanate, barium copper tungstenate, lead magnesium tungstenate, lead cobalt niobate, or a composite oxide comprising at least two of the above compounds.
- the piezoelectric/electrostrictive material may contain a solid solution of an oxide of lanthanum, calcium, strontium, molybdenum, tungsten, barium, niobium, zinc, nickel, manganese, cerium, cadmium, chromium, cobalt, antimony, iron, yttrium, tantalum, lithium, bismuth, tin, copper, etc.
- An antiferroelectric layer may be used in place of the piezoelectric/electrostrictive layer 72 .
- lead zirconate, a composite oxide of lead zirconate and lead tinate, or a composite oxide of lead zirconate, lead tinate, and lead niobate may be used.
- These antiferroelectric materials may contain a solid solution of the above elements.
- a material produced by adding lithium bithmuthate, lead germanate, or the like to the above material e.g., a material produced by adding lithium bithmuthate or lead germanate to a composite oxide of lead zirconate, lead titanate, and lead magnesium niobate, is preferable because it allows the piezoelectric/electrostrictive layer 72 to be sintered at a low temperature and achieve high material characteristics.
- the piezoelectric/electrostrictive layer 72 can also be sintered at a low temperature by adding glass (e.g., silicate glass, borate glass, phosphate glass, germanate glass, or a mixture thereof). However, since excessively adding the glass would invite deterioration of material characteristics, it is desirable to determine an amount of glass to be added depending on the required characteristics.
- the electrode 74 a and 74 b As a pair of electrodes 74 a and 74 b, if the electrode 74 a is formed on the lower surface of the piezoelectric/electrostrictive layer 72 and the electrode 74 b is formed on the upper surface of the piezoelectric/electrostrictive layer 72 , as shown in FIG. 38 , then it is possible to flexurally displace the actuators 34 in one direction so as to be convex toward the cavities 64 , as shown in FIG. 35 , or alternatively it is possible to flexurally displace the actuators 34 in the other direction so as to be convex toward the joint plate 40 .
- the opening width (area) of the cavity 64 should preferably be larger than the width (area) of the actuator body 75 .
- the opening width (area) of the cavity 64 may be equal to or slightly smaller than the width (area) of the actuator body 75 .
- a displacement transmitter 76 for transmitting displacement of the actuator 34 to the joint plate 40 is disposed above the actuator 34 .
- the displacement transmitter 76 may comprise an adhesive which may be a filler-containing adhesive.
- the joint plate 40 and the end face of the displacement transmitter 76 may be fixed (joined) to each other, or may simply be held in contact with each other.
- the term “connect” will be used below as covering “fix” and “contact”. Thus, the actuator 34 and the joint plate 40 are connected to each other by the displacement transmitter 76 .
- the displacement transmitter 76 is not limited to any material, but may preferably be made of thermoplastic resin, thermosetting rein, photosetting resin, moisture-absorption-setting resin, cold-setting resin, or the like.
- acrylic resin modified acrylic resin, epoxy resin, modified epoxy resin, silicone resin, modified silicone resin, vinyl acetate resin, ethylene-vinyl acetate copolymer resin, vinyl butyral resin, cyanoacrylate resin, urethane rein, polyimide resin, metacryl resin, modified metacryl resin, polyolefin resin, special silicone modified polymer, polycarbonate resin, natural rubber, synthetic rubber, etc. are given by way of example.
- vinyl butyral resin, acrylic resin, modified acrylic resin, epoxy resin, modified epoxy resin, or a mixture of two or more of these resins is preferable for their excellent bonding strength.
- epoxy resin, modified epoxy resin, or a mixture thereof is preferable.
- the joint plate 40 is of a material and thickness for providing an optimum rigidity to compensate for the displacement of an actuator which fails to be displaced (defective actuator) due to the displacement of a normal actuator 34 that is connected to the joint plate 40 .
- the joint plate 40 may be made of a metal, ceramics, glass, or an organic resin, but is not limited to any particular materials insofar as they are capable of the functions thereof as described above.
- SUS304 Young's modulus: 193 GPa, coefficient of linear expansion: 17.3 ⁇ 10 ⁇ 6 /C°
- SUS403 Young's modulus: 200 GPa, coefficient of linear expansion: 10.4 ⁇ 10 ⁇ 6 /C°
- zirconium oxide Young's modulus: 245.2 GPa, coefficient of linear expansion: 9.2 ⁇ 10 ⁇ 6 /C°
- glass e.g., Corning 0211 , Young's modulus: 74.4 GPa, coefficient of linear expansion: 7.38 ⁇ 10 ⁇ 6 /C°
- the joint plate 40 comprises an SUS plate having a thickness preferably in the range from 10 ⁇ m to 300 ⁇ m.
- the spacers 42 , 44 should preferably be made of a material which is not deformable with heat and pressure, e.g., thermosetting resin such as epoxy resin or the like, photosetting resin, moisture-absorption-setting resin, cold-setting resin, or the like.
- thermosetting resin such as epoxy resin or the like, photosetting resin, moisture-absorption-setting resin, cold-setting resin, or the like.
- a filler may be contained in the spacers 42 , 44 .
- the spacers 42 , 44 with a filler contained therein has higher hardness and greater heat resistance, strength, and dimensional stability than spacers with no filler contained therein.
- the spacers with a filler contained therein are deformable by a much smaller amount than spacers with no filler contained therein due to an increase in the temperature in the display device 30 A. Stated otherwise, the hardness, heat resistance, and strength of the set resin can be increased and the amount by which it thermally expands and shrinks can be greatly reduced by including a filler in the spacers.
- the picture element assembly 52 may comprise a laminated assembly of a light scattering layer 78 and a transparent layer 80 that are formed on the joint plate 40 .
- the picture element assembly 52 may comprise, in addition to the laminated assembly, any of various combinations including (1) a color filter or a colored scattering body interposed between the transparent layer 80 and the light scattering layer 78 , (2) a light reflecting layer disposed beneath the light scattering layer 78 , and (3) a laminated assembly of a colored scattering body and the transparent layer 80 .
- films such as the electrodes 74 a, 74 b, the piezoelectric/electrostrictive layer 72 , and the spacer 42 on the actuator substrate 32 , and the formation of films such as the picture element assembly 52 and the spacer 44 on the joint plate 40 are not limited to any processes, but may be performed by various known film formation processes.
- films may be grown on the surfaces of the actuator substrate 32 and the joint plate 40 by a film applying process which directly applies a chip-like or web-like film, a thick-film forming process such as a screen printing process, a photolithographic process, a spray dipping process, or a coating process, or a thin-film forming process such as an ion beam process, a sputtering process, a vacuum evaporation process, an ion plating process, a chemical vapor deposition (CVD) process, a plating process, or like, which applies a powder, a paste, a liquid, a gas, ions, or the like as a raw material of a film.
- a film applying process which directly applies a chip-like or web-like film
- a thick-film forming process such as a screen printing process, a photolithographic process, a spray dipping process, or a coating process
- a thin-film forming process such as an ion beam process, a sp
- the refractive index of the optical waveguide plate 38 is desirably in the range from 1.3 to 1.8, or more desirably in the range from 1.4 to 1.7.
- the actuators 34 when the actuators 34 are in a natural state, since the end faces of the picture element assemblies 52 contact the back of the optical waveguide plate 38 by a distance equal to or smaller than the wavelength of the light 33 , the light 33 is reflected by the surfaces of the picture element assemblies 52 as scattered light 82 .
- the scattered light 82 is partly reflected within the optical waveguide plate 38 , but mostly passes through the front face (surface) of the optical waveguide plate 38 without being reflected by the optical waveguide plate 38 . Therefore, all of the actuators 34 are turned on, emitting light whose color corresponds to the color of the color filters and light scattering layers 78 included in the picture element assemblies 52 . As the pixels corresponding to all the actuators 34 are turned on, white light is displayed on the screen of the display device 30 A.
- a low-level voltage (e.g., ⁇ 10 V) is applied as a drive voltage between the electrodes 74 b, 74 a of the actuators 34 to press the end faces of the picture element assemblies 52 against the back of the optical waveguide plate 38 for more reliably turning on the actuators 34 for stable display.
- a high-level drive voltage e.g., 50 V
- those six actuators 34 are flexurally displaced as to be convex toward the cavities 64 , i.e., flexurally displaced downwardly, as shown in FIG. 35 . Consequently, the drive displacement is transmitted through the displacement transmitters 76 and the joint plate 40 to the picture element assembly 52 .
- the end face of the picture element assembly 52 is now spaced from the optical waveguide plate 38 .
- the pixel corresponding to the picture element assembly 52 is turned off, extinguishing the light emission.
- the display device 30 A can control whether there is light emission (scattered light 82 ) on the front face of the optical waveguide plate 38 or not based on whether the picture element assemblies 52 contact the optical waveguide plate 38 or not.
- One frame ( 1/60 sec.) of pixel signals is divided into three times zones (first through third fields), and three-color light sources are switched in each field. For example, light from a red-color light source (R light source) is introduced in the first field, light from a green-color light source (G light source) is introduced in the second field, and light from a blue-color light source (B light source) is introduced in the third field to display a color image with the monochromatic pixel array.
- R light source red-color light source
- G light source green-color light source
- B light source blue-color light source
- the materials of the major structural components of the display device 30 A according to the first specific example have been described above. Materials of other structural components (the light 33 , the actuator substrate 32 , and the optical waveguide plate 38 ) will be described below.
- the light 33 that is applied to the optical waveguide plate 38 may be in either one of ultraviolet, visible, and infrared ranges.
- the light source thereof may be an incandescent lamp, a heavy-hydrogen discharge lamp, a fluorescent lamp, a mercury lamp, a metal halide lamp, a halogen lamp, a xenon lamp, a tritium lamp, a light-emitting diode, a laser, a plasma light source, a hot-cathode tube, a cold-cathode tube, or the like.
- the vibrating section 66 should preferably be made of a highly heat-resistant material. The reason for this is that if the vibrating section 66 is directly supported by the fixed section 68 without using a heat-resistant material such as an organic adhesive or the like, the vibrating section 66 should preferably be made of a highly heat-resistant material in order to prevent itself from being modified when at least the piezoelectric/electrostrictive layer 72 is formed.
- the vibrating section 66 should preferably be made of an electrically insulating material in order to electrically isolate an interconnection (e.g., a row selection line) connected to one electrode 74 a of the electrodes 74 a, 74 b formed on the actuator substrate 32 from an interconnection (e.g., a signal line) connected to the other electrode 74 b.
- an interconnection e.g., a row selection line
- an interconnection e.g., a signal line
- the vibrating section 66 may thus be made of a material such as an enameled material where a highly heat-resistant metal or its surface is covered with a ceramic material such as glass or the like.
- a ceramic material such as glass or the like.
- ceramics is optimum as the material of the vibrating section 66 .
- the ceramics of the vibrating section 66 may be stabilized zirconium oxide, aluminum oxide, magnesium oxide, titanium oxide, spinel, mullite, aluminum nitride, silicon nitride, glass, or a mixture thereof.
- Stabilized zirconium oxide is particularly preferable because it has high mechanical strength, high tenacity, and causes a relatively small chemical reaction with the piezoelectric/ electrostrictive layer 72 and the electrodes 74 a, 74 b even if the vibrating section 66 is thin.
- Stabilized zirconium oxide includes both stabilized zirconium oxide and partially stabilized zirconium oxide. Stabilized zirconium oxide does not cause a phase transition because it has a crystalline structure such as a cubic structure or the like.
- Zirconium oxide causes a phase transition between a monoclinic structure and a tetragonal structure at about 1000° C., and may crack upon such a phase transition.
- Stabilized zirconium oxide contains 1-30 mol % of calcium oxide, magnesium oxide, yttrium oxide, scandium oxide, ytterbium oxide, sodium oxide, or an oxide of a rare earth metal.
- the stabilizer should preferably contain yttrium oxide for increasing the mechanical strength of the vibrating section 66 .
- the stabilizer should preferably contain 1.5 to 6 mol % of yttrium oxide, or more preferably 2 to 4 mol % of yttrium oxide, and furthermore should preferably contain 0.1 to 5 mol % of aluminum oxide.
- the crystalline phase may be a mixture of cubic and monoclinic systems, a mixture of tetragonal and monoclinic systems, or a mixture of cubic, tetragonal and monoclinic systems. Particularly, a mixture of cubic and monoclinic systems or a mixture of tetragonal and monoclinic systems as a major crystalline phase is most preferable from the standpoint of strength, tenacity, and durability.
- the vibrating section 66 is made of ceramics, then it is constructed of relatively many crystal grains.
- the average diameter of the crystal grains should preferably be in the range from 0.05 ⁇ m to 2 ⁇ m and more preferably in the range from 0.1 ⁇ m to 1 ⁇ m.
- the fixed section 68 should preferably be made of ceramics.
- the fixed section 68 may be made of ceramics which is the same as or different from the ceramics of the vibrating section 66 .
- the ceramics of the fixed section 68 may be stabilized zirconium oxide, aluminum oxide, magnesium oxide, titanium oxide, spinel, mullite, aluminum nitride, silicon nitride, glass, or a mixture thereof.
- the actuator substrate 32 used in the display device 30 A according to the first specific example is made of a material containing zirconium oxide as a chief component, a material containing aluminum oxide as a chief component, or a material containing a mixture of zirconium oxide and aluminum oxide as a chief component. Particularly preferable is a material chiefly containing zirconium oxide.
- Clay or the like may be added as a sintering additive.
- Components of such a sintering additive need to be adjusted so that the sintering additive does not contain excessive amounts of materials which can easily be vitrified, e.g., silicon oxide, boron oxide, etc. This is because while these easily vitrifiable materials are advantageous in joining the actuator substrate 32 to the piezoelectric/electrostrictive layer 72 , they promote a reaction between the actuator substrate 32 and the piezoelectric/ electrostrictive layer 72 , making it difficult to keep the desired composition of the piezoelectric/electrostrictive layer 72 and resulting in a reduction in the device characteristics.
- silicon oxide, etc. in the actuator substrate 32 should preferably be limited to 3% by weight or less or more preferably to 1% by weight or less.
- the chief component referred to above is a component which occurs at 50% by weight or more.
- the optical waveguide plate 38 has such a refractive index that the light 33 introduced therein is totally reflected within the optical waveguide plate 38 without passing through front and back surfaces thereof.
- the optical waveguide plate 38 is required to have a uniform and high transmittance in the wavelength range of the introduced light 33 .
- the optical waveguide plate 38 is not limited to any materials insofar as they have the above characteristics. Specific materials thereof include glass, quartz, light-transmissive plastics such as acrylic resin or the like, light-transmissive ceramics, or a plural-layer structural body of materials having different refractive indexes, or a material having a coating layer on its surface.
- the inventive example has the same structure as the display device 30 A according to the first specific example, and the comparative example has the same structure as a conventional display device 300 shown in FIG. 52 .
- the aperture ratio is determined by a contact area of six picture element assemblies 310 , for example, formed on respective actuators 306 on an actuator substrate 308 shown in FIG. 52 . Since the area of each of the picture element assemblies 310 is limited by the area of the corresponding actuator 306 and there is a gap between adjacent picture element assemblies 310 , the end faces of the picture element assemblies 310 serve as an emission region 90 (shown shaded in FIG. 39B ), and the gap between the picture element assemblies 310 serves as a non-emission region 92 . Therefore, the emission region 90 is defined by six dot-shaped regions surrounded by the non-emission region 92 .
- the aperture ratio is determined by a contact area of one picture element assembly 52 formed on the joint plate 40 shown in FIG. 35 .
- the end face of the picture element assembly 52 serves as an emission region 90
- the other portion serves as a non-emission region 92 .
- the emission region 90 can freely be established irrespective of the areas of the actuator 34 on the actuator substrate 32 and the displacement transmitter 76 , and can include the non-emission region 92 in the comparative example.
- the emission region 90 can be widened to a range close to the cell 50 .
- the aperture ratio can be made much greater than the aperture ratio according to the comparative example.
- the voltage applied to the actuator 306 is controlled to change the amount of displacement of the picture element assembly 310 to provide a state (emitted state) in which the picture element assembly 310 contacts an optical waveguide plate 304 and a state (extinguished state) in which the picture element assembly 310 is spaced from the optical waveguide plate 304 .
- the shape of a vibrating section 314 of the actuator 306 is reflected to a certain extent on the upper surface of the picture element assembly 310 . Therefore, when the picture element assembly 310 is spaced from the optical waveguide plate 304 , the upper surface of the picture element assembly 310 is made concave toward the optical waveguide plate 304 , i.e., forms a concavity 316 .
- the central area of the end face of the picture element assembly 310 is largely displaced as it corresponds to a region of the actuator 306 where the maximum amount of displacement is obtained.
- the displacement of the peripheral edge area of the picture element assembly 310 is small as it corresponds to a region of the actuator 306 where the amount of displacement is small.
- V 1 a voltage applied to achieve a certain amount of displacement at the central area of the picture element assembly 310
- V 2 a voltage applied to achieve the same amount of displacement at the peripheral edge area of the picture element assembly 310
- V 2 >V 1 .
- the difference between the amounts of displacement at the above areas manifests itself if the area of the end face of the picture element assembly 310 is increased for the purpose of increasing the aperture ratio of the pixel.
- the distance between the optical waveguide plate 304 and the upper end of the picture element assembly 310 has to be equal to or greater than a distance d in order to space the picture element assembly 310 fully from the optical waveguide plate 304 , then the amount of displacement of the peripheral edge area of the picture element assembly 310 needs to be equal to or greater than the distance d. Therefore, the voltage to be applied to the actuator 306 has to be determined in view of the region of the actuator 306 which corresponds to the peripheral edge area of the picture element assembly 310 .
- the amount of displacement of the central area of the end face of the picture element assembly 310 reaches a distance D which is greater than the distance d.
- the voltage applied to the actuator 34 is controlled, and the displacement thereof is transmitted to the displacement transmitter 76 and the joint plate 40 to change the amount of displacement of the picture element assembly 52 to provide a state (emitted state) in which the picture element assembly 52 contacts the optical waveguide plate 38 and a state (extinguished state) in which the picture element assembly 52 is spaced from the optical waveguide plate 38 .
- the picture element assembly 52 formed on the joint plate 40 has a flat end face regardless of the shape of the vibrating section 66 of the actuator 34 .
- the displacement transmitter 76 can be of a narrow configuration.
- the displacement transmitter 76 can be installed in a central region of the actuator 34 where the maximum amount of displacement is obtained, and the amount of displacement of the displacement transmitter 76 can be set to a value close to the maximum amount of displacement of the actuator 34 .
- the voltage to be applied to the actuator 34 may be determined in view of the displacement of the region of the actuator 34 where the maximum amount of displacement is obtained.
- the voltage can thus be much lower than the voltage in the comparative example. As a result, the power consumption can be reduced, the voltage and cost of the driver circuit can be lowered, and the reliability can be increased.
- one pixel is made up of six picture element assemblies 210 , for example, formed on the respective actuators 306 on the actuator substrate 308 (see FIG. 32 ).
- one pixel is made up of one picture element assembly 52 formed on the joint plate 40 (see FIG. 41 ).
- Six actuators 34 are present below the joint plate 40 .
- Numbers 1 , 2 , 3 , . . . 6 shown in FIGS. 39A and 39B represent defective actuators as they increase in the sequence of the numbers.
- FIG. 42 shows a luminance change when the pixel is turned on and off with respect to the defect ratio (the number of defective actuators/the number of actuators that make up one pixel) of the actuators 206 or 34 .
- the luminance change of the comparative example falls in proportion to the increase in the number of defective actuators as indicated by the solid-line curve A in FIG. 42 .
- the luminance change does not substantially fall if the defect ratio of the actuators 34 is equal to or smaller than 2/6, and the luminance change falls by about 5% if the defect ratio is 3/6. According to the inventive example, therefore, it is possible to keep the luminance change at a larger level in the presence of defective actuators than according to the comparative example.
- one pixel is made up of four actuators 34 in an arrangement similar to the inventive example, then the luminance change does not fall at a defect ratio of 1 ⁇ 4 or less. If one pixel is made up of three actuators 34 , then the luminance change does not fall at a defect ratio of 1 ⁇ 3 or less.
- the luminance change falls by 50% at a defect ratio of 1 ⁇ 2 or less. If one pixel is made up of two actuators in an arrangement similar to the inventive example, then the reduction of the luminance change is kept within 25% at a defect ratio of 1 ⁇ 2 or less.
- the single joint plate 40 is disposed between the optical waveguide plate 38 and the actuator substrate 32 , and the spacers 44 are disposed between the actuator substrate 32 and the joint plate 40 and between the optical waveguide plate 38 and the joint plate 40 in alignment with the respective cells 50 . Consequently, in regions of the joint plate 40 close to the spacers 42 , 44 , the displacement of the joint plate 40 itself tends to be reduced due to the tension of the joint plate 40 (its rigidity is increased). However, as shown in FIG.
- portions of the joint plate 40 that are narrowed by the slits 110 , i.e., portions (hereinafter simply referred to as arms 111 ) interconnecting the boundary regions (fixed regions) of the cells 50 and regions (movable regions) corresponding to the picture element assemblies 52 .
- the arms 111 In order to keep the displacement of the regions of the joint plate 40 which correspond to the picture element assemblies 52 and allow the joint plate 40 to be handled in the fabrication process, it is of course suitable to give the arms 111 appropriate rigidity, and it is preferable to optimize the shape, thickness, and structure of the arms 111 . More preferably, the movable regions should be of increased flexural rigidity to compensate for the displacement of defective actuators, and the arms 111 should be of reduced flexural rigidity.
- the slits 110 can be formed in the joint plate 40 and the thickness of the arms 111 can be made larger than the surrounding regions by a half-etching process, a sand blasting process, or the like.
- the fixed regions may be clamped and the movable regions may then be lowered in the direction of the thickness thereof to elongate the arms 11 , and thereafter the movable regions may be raised in the opposite direction to turn the side elevational shape of the arms 111 into an arch shape, which is effective to reduce the reduction in the displacement under the tension of the arms 111 .
- the planar shape of the arms 111 may be an L shape, a swirling shape, a bellows shape, or the like, as well as the straight shape shown in FIG. 43 , thus increasing the length of the arms 111 .
- a display device 30 B according to a second specific example will be described below with reference to FIG. 44 .
- Those parts of the display device 30 B which correspond to those of the display device shown in FIG. 35 are denoted by identical reference characters, and will not be described in detail below.
- the display device 30 B according to the second specific example is of substantially the same structure of the display device 30 A according to the first specific example, but differs therefrom in that the joint plate 40 is divided into segments corresponding to the cells 50 . That is, a plurality of joint plates 40 are arranged in a plane between the optical waveguide plate 38 and the actuator substrate 32 .
- a plurality of spacers 112 are formed between the optical waveguide plate 38 and the actuator substrate 32 , and are interposed between the optical waveguide plate 38 and the actuator substrate 32 through gaps between adjacent joint plates 40 .
- the joint plates 40 are free of interference with the tension of adjacent joint plates 40 and the spacers 112 when they are displaced.
- the joint plate 40 is somewhat affected by a reduction in the displacement due to the defective actuator. If six actuators 34 , for example, are assigned to one picture element assembly 52 , then a luminance change is 0% when the defect ratio of actuators 34 is 1 ⁇ 6, about 3% when the defect ratio of actuators 34 is 2/6, and about 5% when the defect ratio of actuators 34 is 3/6. Therefore, the display device 30 B according to the second specific example has substantially the same performance as the display device 30 A according to the first specific example.
- a variable capacitor 120 has a drive section 36 including a plurality of actuators 34 arranged in a plane on an actuator substrate 32 , a fixed electrode 122 comprising a single metal plate disposed facing the drive section 36 , and a movable electrode 124 comprising a single metal plate which is disposed between the actuator substrate 32 and the fixed electrode 122 and to which drive forces from the actuators 34 of the drive section 36 are transmitted through displacement transmitters 76 .
- the fixed electrodes 122 are fixed to the actuator substrate 32 by spacers 112 that are interposed between the fixed electrode 122 and the actuator substrate 32 .
- variable capacitor 120 With the variable capacitor 120 , the movable electrode 124 is moved toward and away from the fixed electrode 122 when the actuators 34 are operated. That is, a distance da between the movable electrode 124 and the fixed electrode 122 is changed accurately by the actuators 34 , changing the electrostatic capacitance between the electrodes 122 , 124 .
- the dynamic range of the electrostatic capacitance can be increased by increasing the confronting areas of the fixed electrode 122 and the movable electrode 124 . Since a plurality of actuators 34 are assigned to a single movable electrode 124 , the distance between the fixed electrode 122 and the movable electrode 124 can accurately be controlled.
- variable capacitor 120 Even if there is a defective actuator, the characteristics of the variable capacitor 120 , i.e., the changing characteristics of the electrostatic capacitance with respect to the level of a control signal supplied to the variable capacitor 120 , remain almost unchanged. Therefore, the yield of variable capacitors 120 of stable characteristics is increased.
- each of the fixed electrode 122 and the movable electrode 124 comprises a metal plate.
- FIG. 46 shows a variable capacitor 120 a according to a modification in which a fixed electrode 122 comprises a plate member 125 made of a desired material such as glass, ceramics, resin film, or the like and an electrically conductive film 126 formed on the plate member 125 , and a movable electrode 124 comprises a plate member 127 made of a desired material such as glass, ceramics, resin film, or the like and an electrically conductive film 128 formed on the plate member 127 .
- An interference optical modulator 130 has a drive section 36 including a plurality of actuators 34 arranged in a plane on an actuator substrate 32 , a single transparent plate 132 facing the drive section 36 , and a single mirror member 134 which is disposed between the actuator substrate 32 and the transparent plate 132 and to which drive forces from the actuators 34 of the drive section 36 are transmitted through displacement transmitters 76 .
- the transparent plate 132 is fixed to the actuator substrate 32 by spacers 112 that are interposed between the transparent plate 132 and the actuator substrate 32 .
- the interference optical modulator 130 when input light Li is applied through the transparent plate 132 to the mirror member 134 , light (first reflected light L 1 ) reflected by the boundary between the reverse side of the transparent plate 132 (which faces the mirror member 134 ) and light (second reflected light L 2 ) reflected by the surface of the mirror member 134 are emitted as output light Lo.
- the first reflected light L 1 and the second reflected light L 2 interfere with each other, and the spectral distribution of the output light Lo is determined by the distance db between the transparent plate 132 and the mirror member 134 .
- the interference optical modulator 130 can be used as a color display device, a color filter, a light switch, or the like. Particularly, inasmuch as a joint plate is used in the interference section (the mirror member 134 ), the surface to which light is applied may be made flat, and the interference section may be provided in a wide area. Even if some of the actuators are defective, they have substantially no effect on the displacement of the interference section. In the above example, the upper surface of the interference section is flat. However, the upper surface of the interference section may be slanted or may have surface irregularities as required.
- a mirror member 134 may comprise a metal plate 135 having a mirror surface 135 a which faces the transparent plate 132 (see FIG. 47 ).
- a mirror member 134 may comprise a plate member 136 and a light reflecting film 137 directly formed on a portion of the surface of the plate member 136 which faces the transparent plate 132 .
- a mirror member 134 may comprise a plate member 136 , and a light reflecting film 137 formed on a portion of the surface of the plate member 136 which faces the transparent plate 132 , with a base layer 138 interposed between the plate member 136 and the light reflecting film 137 .
- the surface of the plate member 136 should preferably be a light absorbing surface to prevent unwanted scattered light from being produced.
- Each of the actuator devices 10 A through 10 D according to the first through fourth embodiments employs the substrate 12 .
- a structure free of the substrate 12 may also be employed.
- An actuator device 10 E according to a fifth embodiment which is free of the substrate 12 will be described below with reference to FIG. 49 .
- the actuator device 10 E employs a laminated assembly 156 of a vibrating plate layer 152 and a piezoelectric function layer 154 , instead of the substrate 12 .
- the piezoelectric function layer 154 has a plurality of lower electrodes 74 a formed on the vibrating plate layer 152 , a piezoelectric/electrostrictive layer 72 formed on the entire surface of the vibrating plate layer 152 including the lower electrodes 74 a, and a plurality of upper electrodes 74 b formed on the piezoelectric/electrostrictive layer 72 .
- the vibrating plate layer 152 amplifies the displacement amount of the piezoelectric/electrostrictive layer 72 .
- the laminated assembly 156 has a structure including an array of actuators 14 , and serves as a drive section 16 .
- the vibrating plate layer 152 may be made of the same material as or may be made of a different material from the piezoelectric/electrostrictive layer 72 of the piezoelectric function layer 154 .
- the laminated assembly 156 may be produced by laminating ceramic green sheets, and the upper electrodes 74 b and the lower electrodes 74 a may easily be formed by a screen printing process or the like.
- the actuator device 10 E has the drive section 16 , a single first plate member 18 to which drive forces from the actuators 14 of the drive section 16 are transmitted, and a single second plate member 20 confronting the first plate member 18 .
- a plurality of spacers 22 are disposed between the first plate member 18 and the second plate member 20 , forming m cells 15 , for example.
- a plurality of spacers 24 are also disposed between the first plate member 18 and the laminated assembly 156 forming the m cells 15 .
- N actuators 14 are assigned to each of the cells 15 .
- Displacement transmitters 76 for transmitting drive forces from the actuators 14 to the first plate member 18 are formed on the respective actuators 14 .
- the upper electrodes 74 b of the laminated assembly 156 have electrode patterns divided in the respective cells 15 or electrode patterns divided in respective rows, and the lower electrodes 74 a have electrode patterns divided in the respective actuators 14 .
- the electrodes 74 a, 74 d may be vertically switched around.
- the laminated assembly 156 is disposed on a fixed plate 158 by a plurality of spacers 160 , 162 .
- the spacers 160 , 162 on the fixed plate 158 include, for example, a plurality of first spacers 160 positionally aligned with the spacers 24 disposed between the first plate member 18 and the laminated assembly 156 , and a plurality of second spacers 162 disposed in the cells 15 in regions except for the actuators 14 .
- portions (which are not positionally aligned with the actuators 14 ) of the vibrating plate layer 152 are fixed by the first and second spacers 160 , 162 disposed on the fixed plate 158 , spaces surrounded by the fixed plate 158 , the first and second spacers 160 , 162 , and the vibrating plate layer 152 have the same functions as the cavities 64 in the actuator substrate 32 shown in FIG. 35 , making it easy to determine the direction in which the actuators 14 are displaced.
- the fixed plate 158 is effective to increase the mechanical strength of the actuator device 10 E itself, which can easily be handled while being delivered or manufactured.
- a plurality of piezoelectric function layers 154 may be laminated to increase the amount of displacement and generated forces of the actuators 14 . Any arbitrary displacement modes can be achieved by changing the installed positions of the spacers 22 , 24 , 160 , and 162 . Desired displacements can be obtained by changing the electrode patterns of the upper electrodes 74 b and the lower electrodes 74 a .
- the second plate member 20 is used as the optical waveguide plate 38 , light shield layers 70 (indicated by the two-dot-and-dash lines) are disposed between the second plate member 20 and the spacers 22 , and picture element assemblies 52 (indicated by the two-dot-and-dash lines) are disposed on the first plate member 18 .
- FIG. 50 shows an actuator device 10 Ea according to a first modification of the actuator device 10 E according to the fifth embodiment.
- the actuator device 10 Ea according to the first modification is free of the second plate member 20 .
- FIG. 51 shows an actuator device 10 Eb according to a second modification which is free of the second plate member 20 and the fixed plate 158 .
- the lower electrodes 74 a have electrode patterns divided in the respective actuators 14 , those regions which are free of the lower electrodes 74 a are not flexurally displaced and are joined to the regions where the spacers 24 are present. Therefore, the actuators 14 are flexurally displaced while the regions which are free of the lower electrodes 74 a are joined to the regions where the spacers 24 are present at the same height.
- the actuator device (including the various modifications) according to the fifth embodiment which has the piezoelectric function layer can more flexibly and easily be changed in design than the structure having the substrate 12 because the magnitude of the flexural displacement and the pattern of the displacement can be changed as desired by the electrode patterns of the upper and lower electrodes. The occurrence of defective actuators is also reduced. These advantages are produced because the piezoelectric function layer is uniformly formed of a ceramic green sheet.
- the actuator device according to the present invention is not limited to the above embodiments, but may incorporate various structures without departing from the essential features of the present invention.
Abstract
Description
- 1. Field of the Invention
- The present invention relates to an actuator device which is applicable to a display device and which is also applicable to various applications including an optical modulator, a variable capacitor, etc.
- 2. Description of the Related Art
- It is known in the art that an actuator device having a plurality of actuators can be applied to a display device, and can also be applied to various applications including an optical modulator, a variable capacitor, etc. (see Japanese Laid-Open Patent Publication No. 11-339561, for example). With regard to the display device, for example, the applicant of the present application has proposed a novel display device in order to achieve the following advantages:
- (1) A clearance (gap) between an optical waveguide plate and a picture element assembly can easily be formed, and can be formed uniformly over all pixels.
- (2) The size of the gap can easily be controlled.
- (3) The optical waveguide plate can be prevented from sticking to the picture element assembly, and the response speed can effectively be increased.
- (4) The contact surface of the picture element assembly (the surface thereof contacting the optical waveguide plate) can smoothly be formed in order to introduce light efficiently into the picture element assembly when the picture element assembly contacts the optical waveguide plate.
- (5) The response speed of pixels can be maintained.
- (6) A uniform level of luminance can be obtained over all pixels.
- (7) The luminance of pixels can be increased.
- As shown in
FIGS. 52 and 53 , adisplay device 200 has anoptical waveguide plate 204 into which light 202 is introduced, an actuator substrate 208 facing one surface of theoptical waveguide plate 204 and having asmany actuators 206 as the number of pixels,picture element assemblies 210 formed on theactuators 206 of the actuator substrate 208, andspacers 212 disposed between theoptical waveguide plate 204 and the actuator substrate 208 in regions other than the picture element assemblies 210 (see, for example, Japanese Laid-Open Patent Publication No. 2003-161896).Light shield layers 218 are interposed between theoptical waveguide plate 204 and thespacers 212. - Applications using piezoelectric actuators are disclosed in Japanese Laid-Open Patent Publication No. 11-252333, Japanese Laid-Open Patent Publication No. 2003-52181, Japanese Laid-Open Patent Publication No. 2000-314381, Japanese Laid-Open Patent Publication No. 2003-74475, and WO 02/084751 A1.
- In the
display device 200, one pixel may be made up of six actuators positioned in two rows and three columns. If oneactuator 206 is defective in such a configuration, then a spot corresponding to thatactuator 206 is displayed as a black or white dot regardless of an image displayed by thedisplay device 200, tending to cause a disadvantage to increase the image quality. - Specifically, even if one actuator is defective in the conventional actuator device, then since the defective actuator adversely affects the quality of the actuator device, it tends to pose a limitation to increase the yield. Another problem is that the area of a region that is displaced by an actuator, i.e., an effective area, cannot be increased.
- The present invention has been made in view of the above drawbacks. It is an object of the present invention to provide an actuator device which, even when it has a defective actuator, can compensate for the displacement of the defective actuator with a normal actuator, has an increased yield, and has an increased effective area.
- Another object of the present invention is to provide an actuator device which, if applied as a display device, offers the following advantages:
- (1) Even when the actuator device has a defective actuator, the displacement thereof can be compensated for by a normal actuator, thus eliminating a defective pixel.
- (2) The aperture ratio of a pixel can be increased.
- (3) One pixel can be turned on and off by the displacement of a plurality of actuators, and a region of maximum displacement in one actuator can be utilized for increased luminance and contrast.
- (4) The freedom of a pixel shape can be increased.
- An actuator device according to the present invention has a plurality of actuators arranged in a plane, and a plate member to which drive forces from the actuators are transmitted, each of the actuators having a vibrating section and a fixed section.
- Drive forces from the actuators arranged in the plane are transmitted the plate member. Since each of the actuators is displaced vertically, the plate member is displaced in a direction substantially perpendicular to its plane.
- Even when some of the actuators become defective, their displacement can be compensated for by the normal actuators. Therefore, the yield of the actuator devices is increased. Furthermore, the area of a portion that is displaced by the actuator, i.e., an effective area, can be increased. Particularly, three or more actuators should preferably be joined by the plate member. The probability of a failure is reduced, and the plate member can be controlled in displacement more stably. If the actuators are displaced in a z-axis direction and the plate member has its plane lying in a xy-plane direction, then three or more actuators may be arrayed in the x-axis direction, or two or more actuators may be arrayed in each of the x- and y-axis directions.
- The rigidity of the plate member should preferably be greater than the rigidity of the vibrating section. With this arrangement, even when one actuator fails due to cracking or wire breakage, the plate member is displaced when another actuator is displaced, producing forces to displace the vibrating section of the faulty actuator. Consequently, even in the event of a failure of one actuator, the displacement of the entire plate member is not affected thereby, making it possible to compensate for the faulty region.
- Since the actuators have the vibrating sections, any faulty actuator can easily be displaced under external forces. Such defect compensation cannot be obtained by a laminated actuator, for example, which does not have the vibrating sections.
- The plate member may have concavities and convexities. In this case, the geometrical moment of inertia of the plate member is increased to increase the flexural rigidity of the plate member. Because the rigidity can be increased with a small amount of material, the concavities and the convexities are effective in reducing the weight of the actuator device. Inasmuch as the inertial mass is reduced, the response speed of the actuators is increased. The concavities and the convexities may be provided as grooves, or may be arranged in a matrix or a staggered pattern. The concavities and the convexities may have an X shape, a circular shape, a grid shape, a striped shape, a comb-toothed shape, or the like as viewed in plan, or may have a dimple shape, a saw-toothed shape, a peak shape, a wedge shape, a rectangular shape, or the like, as viewed in cross section. The concavities and the convexities may be formed on both surfaces of the plate member or on one surface of the plate member. The plate member itself may be of a wavy shape.
- The actuators and the plate member may be connected to each other by displacement transmitters.
- The flexural rigidity of the plate member should preferably be 10 times the flexural rigidity of the vibrating sections or greater. This reduces the amount of flexing of the plate member. In this case, there is obtained a structure which is less susceptible to manufacturing irregularities with respect to the distance between the actuators and the size of the displacement transmitter (if the actuators and the plate member are connected to each other by the displacement transmitter).
- The drive forces of the actuators may be produced by a generation source which comprises a piezoelectric element, an electrostatic force, a magnetic force, an electromagnetic force, a spring, a wire, or the like.
- If a piezoelectric element is used as the generation source, then it may have a unimorph structure, a bimorph structure, a monomorph structure, a structure in which a piezoelectric actuator is formed on the vibrating section, or a structure in which a piezoelectric actuator is formed on the vibrating section and the fixed section.
- If an electrostatic force is used as the generation source, then an electrode may be disposed on a surface of the vibrating section which faces the fixed section and an electrode may be disposed on a surface of the fixed section which faces the vibrating section, and a voltage may be applied between the electrodes to generate an electrostatic force which displaces the vibrating section. Electrodes may be formed on the surface of the vibrating section, or an insulator may be interposed between the different electrodes to prevent them from contacting each other and being short-circuited, or the surfaces of the electrodes may be covered with an insulator.
- In the process of displacing the actuators, it is preferable for the distance between the vibrating sections and the plate member to remain substantially unchanged. For example, if the displacement transmitter is interposed between the vibrating sections and the plate member, then it is preferable that the thickness (height) of the displacement transmitter be not essentially changed by the displacement of the actuators (not subject to compressive deformation, tensile deformation, and buckling deformation). In this case, compressive deformation and tensile deformation can be reduced by adding a filler to the displacement transmitter.
- In the above arrangement, the actuators should preferably have portions connected to the displacement transmitter and having a width smaller than the width of the vibrating section. The displacement of the vibrating section and forces produced thereby can reliably be transmitted to the plate member by the displacement transmitter. In this case, it is preferable that the displacement transmitter does not overlap the fixed section so as not to obstruct the displacement of the displacement transmitter, and it is preferable that the displacement transmitter be not too small with respect to the vibrating section so that the vibrating section and the first plate member are reliably fixed to each other. Furthermore, it is preferable for the displacement transmitter to connect the plate member and the vibrating section at a position including a portion of the vibrating section where the displacement is the greatest. As the displacement and generated forces differ depending on the location of the vibrating section, even if the joint between the vibrating section and the displacement transmitter does not include a portion of the vibrating section which causes the largest displacement, optimum values can be obtained from generated forces and a required amount of displacement. Specifically, the width of the displacement transmitter should be in the range from 5% to 99%, or preferably in the range from 30% to 90%, of the width of the vibrating section. In terms of areas, the cross-sectional area of the displacement transmitter should be in the range from 0.5% to 99%, or preferably in the range from 10% to 90%, of the cross-sectional area of the vibrating section. The ratio of the height to width of the displacement transmitter, i.e., the aspect ratio of the displacement transmitter, should be smaller than 1, or preferably smaller than 0.2.
- If the rigidity of the vibrating section is greater than the rigidity of the plate member, then the plate member tends to flex without displacing the vibrating section of a faulty actuator, and the plate member includes a portion which is displaced and a portion which is not displaced. Therefore, such a rigidity setting is not preferable.
- The vibrating sections may be of a convex shape which is convex toward the plate member or concave toward the plate member. The vibrating sections of such a shape are more effective to increase the response of the actuators than if the vibrating sections are not of a convex shape (e.g., they are flat), and allow adjacent actuators to compensate for a displacement even if an actuator fails.
- The reasons for the above advantages are as follows: In the presence of the plate member, the vibrating sections need to displace a large mass, and undergoes a larger load than if it were not for the plate member. Since the vibrating sections are of a convex shape, their drive forces become stronger to keep response at a higher level. The rigidity is increased to sufficiently bear the mass of the plate member that is applied to the vibrating sections.
- In the event of a failure of an actuator, the first plate member driven by the adjacent actuators displaces the vibrating section. At this time, it is desirable that reactive forces from the vibrating section be small. The convex shape is considered to have such characteristics that it increases drive forces but prevents reactive forces from increasing when displaced by the plate member.
- The convex shape of the vibrating section may be formed in the longitudinal direction of a beam. Alternatively, the convex shape of the vibrating section may be formed in a direction parallel to the joint between the vibrating section and the fixed section. Particularly, the vibrating section should preferably be of a wing shape (W shape) in the longitudinal direction of the beam. If the vibrating section has a wing shape, the width of the convex shape, i.e., the distance between valleys, should preferably be ⅓ of the beam length or greater. If the vibrating section is convex toward the plate member, then the vertex of the convex shape should preferably project toward the plate member beyond the height of the fixed section.
- If the vibrating section is of the convex shape, then the vibrating sections should preferably be of an arch shape or a wavy shape. The structure in which the vibrating sections are of a convex shape is particularly preferably used in an arrangement wherein the vibrating sections have both ends connected to the fixed section and an arrangement wherein the peripheral region of the vibrating sections is connected to the fixed section. If cavities are present below the vibrating sections, then the cavities may be filled with a liquid. In such a case, the peripheral region of the vibrating sections needs to be connected to the fixed section to prevent the liquid from leaking.
- In the event of a failure of an actuator, the plate member is displaced by a normal actuator, and the vibrating section of the faulty actuator is depressed by the displacement transmitter. If the vibrating section whose peripheral region is connected to the fixed section is of a flat cross-sectional shape, then forces tending to obstruct the displacement are liable to increase under the tension of the vibrating section which is kept taut. This is because the vibrating section is extended in its longitudinal direction for producing the above displacement. If the vibrating section is of an arch or wavy shape, then since the vibrating section itself has a larger length than the minimum distance between its joints to the fixed section, forces tending to obstruct the displacement are relatively weak when the vibrating section undergoes forces from the displacement transmitter.
- If the vibrating section is of an arch shape, then when the actuator is displaced under drive forces in a direction away from the plate member, the vibrating section should preferably have an arch shape that is convex toward the plate member. When the actuator is displaced under drive forces in a direction toward the plate member, the vibrating section should preferably have an arch shape that is concave toward the plate member. If the actuator in which the vibrating section is convex toward the plate member is displaced toward the plate member, then the length of the vibrating section is increased and forces tending to obstruct the displacement thereof are increased. When the actuator in which the vibrating section is convex toward the plate member undergoes forces applied in a direction away from the plate member through the displacement transmitter, the actuator is displaced as the vibrating section flexes.
- With the vibrating section fixed at its both ends or peripheral region to the fixed section, since the rigidity of the vibrating section is not too high, the actuator device is highly effective to perform compensation for a failure. The degree of freedom for design is also increased. The vibrating section may also be fixed at one end to the fixed section.
- If the vibrating section is of an arch shape or a wavy shape, the height (or depth) of the convexity (or concavity) thereof toward the plate member should preferably be greater than the height (or depth) corresponding to the thickness of the vibrating section.
- For keeping the responsiveness of the actuator, the rigidity of the vibrating section needs to be not too small and should naturally be selected in view of the thickness, width, beam length, shape, material, etc. of the vibrating section. The convexity or concavity of the convex shape does not have to be formed in the central region of the vibrating section.
- Another actuator device according to the present invention has a plurality of cells arranged in a plane, each of the cells having a plurality of actuators arranged in a plane and a plate member to which drive forces from the actuators are transmitted, each of the actuators having a vibrating section and a fixed section. The cells may have the same size (the cells serve as unit cells) or may have different sizes. In this case, the rigidity of the plate member should preferably be greater than the rigidity of the vibrating section, as with the invention described above.
- In the present invention, the plate members of the cells may be connected to each other. In this case, the plate members should preferably be connected to each other by joints, the rigidity of all or some of the joints being smaller than the rigidity of the plate member. The rigidity of all or some of the joints may be made smaller than the rigidity of the plate member by using a material of less rigidity for the joints than the plate member, or making the joints thinner than the plate member or making the width of the joints smaller than the width of the plate member if the joints and the plate member are made of the same material.
- The above actuator device may further have gap forming members for forming gaps between the fixed sections and the plate members in the actuators, the joints interconnecting the plate members and the fixed sections being joined to each other by the gap forming members. With this arrangement, the distance between the plate member in the cells and the fixed sections can be established accurately and reliably.
- The gap forming members that are present between the joints and the plate member offer the following advantages:
- If the fixed section has different heights depending on the location, e.g., if the substrate has undulations (which are often unavoidable in the manufacturing process) when a plurality of actuators are to be formed on one substrate, the distance between the plate member disposed above the substrate and the fixed section varies depending on the location, possibly resulting in direct contact between the actuators and the plate member. In this case, the plate member is partly strained, tending to fail to operate the plate member as desired with the actuators.
- The gap forming members that are present on the fixed section do not give rise to the above problem even if the substrate has undulations because the distance between the plate member and the fixed section is maintained by the gap forming members.
- The actuators that are connected to the plate member have their displacement characteristics affected thereby. As the distance between the plate member and the fixed section is determined by the gap forming members, the degree of a change in the displacement characteristics is kept constant irrespective of the location, and the gap forming members are highly effective to prevent the displacement characteristics from varying. For example, since the thickness of the displacement transmitters is uniformized, the effect thereof on the displacement characteristics of the actuators is uniformized.
- In the absence of the gap forming members, when the actuators and the plate member are partly displaced considerably closely to each other, the displacement transmitters for connecting the actuators and the plate member tend to spread more greatly than the size of the actuators, possibly impairing operation of the actuators. This drawback can be avoided by adding the gap forming members.
- If the height of the gap forming members is greater than necessary, then shortcomings such as characteristic changes are liable to occur due to expansion or shrinkage of the gap forming members themselves or an increase in the load on the actuators. The gap forming members can sufficiently be made effective by setting the gap forming members to an appropriate height.
- The actuator device may further have a second plate member, the second plate member having a plate surface facing a plate surface of the plate member (hereinafter referred to as first plate member). If it is assumed that the first plate member and the second plate member are disposed closely facing each other, then the gap forming members should preferably be disposed and connected such that the interval between the second plate member and the first plate member becomes a predetermined distance. In this case, the gap forming members should preferably be disposed and connected between the second plate member and the fixed section. If the joints of the first plate member and the fixed section are connected by the gap forming members, then the joints of the first plate member and the second plate member should preferably be connected by other gap forming members.
- The gap forming members should preferably be arranged such that they are associated with the respective cells. This is because the gap forming members can firmly be fixed, and the gap distance can accurately and reliably be established. If the effective areas of the cells are reduced due to the gap forming members associated with the respective cells, then for the purpose of increasing the effective area efficiency, a plurality of successive cells may be grouped into one large cell, and gap forming members may be associated with each large cell. Gap forming members may be provided on only the outer circumference of the actuator device.
- The gap forming members may be formed in a grid pattern so as to surround cells. Alternatively, the gap forming members may be formed in a striped pattern along confronting sides of cells. The gap forming members of a columnar shape and may be formed on the four corners of the four sides of the cells.
- If the actuator device according to the present invention is constructed as a display device, i.e., if the second plate member comprises an optical waveguide plate into which light from a light source is introduced, and picture element assemblies are disposed on a surface of the plate member which faces the optical waveguide plate, wherein the actuator device serves as a display device for controlling light leaking from the optical waveguide plate with the picture element assemblies as they are brought into and out of contact with the optical waveguide plate, then the actuator device offers the following advantages:
- (1) Even when the actuator device has a defective actuator, the displacement thereof can be compensated for by a normal actuator, thus eliminating a defective pixel.
- (2) The aperture ratio of a pixel can be increased.
- (3) One pixel can be turned on and off by the displacement of a plurality of actuators, and a region of maximum displacement in one actuator can be utilized for increased luminance and contrast.
- (4) The freedom of a pixel shape can be increased.
- If a fixed electrode of a variable capacitor is disposed on the second plate member and a movable electrode of the variable capacitor is disposed on the plate member, then the variable capacitor may have its capacitance variable as the movable electrode is movable toward and/or away from the fixed electrode when the actuators are operated. The second plate member itself may serve as the fixed electrode of the variable capacitor or the plate member itself may serve as the movable electrode of the variable capacitor.
- If the second plate member comprises a transparent plate, and the plate member has a light reflecting surface in a region facing the second plate member, then the actuator device can serve as an interference optical modulator. Specifically, when input light is applied through the second plate member (transparent plate) to the plate member, light (first reflected light) reflected by the boundary between the reverse side of the transparent plate (which faces the plate member) and light (second reflected light) reflected by a light reflecting surface are emitted as output light. The first reflected light and the second reflected light interfere with each other, and the spectral distribution of the output light is adjusted by the displacement of the plate member and the second plate member. The actuator device thus functions as an interference optical modulator. The portion of the plate member which faces the second plate member may be turned into the light reflecting surface by constructing the surface of the plate member which faces the second plate member as a mirror surface, forming a light reflecting film on the region of the plate member which faces the second plate member, or forming a light reflecting film on that region with a base layer interposed therebetween. In order to prevent unwanted reflections, a layer such as a anti-reflection film or the like may be provided on both surfaces or one surface of the transparent plate.
- As described above, with the actuator device according to the present invention, even when some of the actuators become defective, their displacement can be compensated for by the normal actuators. Therefore, the yield of the actuator devices is increased.
- The actuator device according to the present invention as applied to a display device offers the following advantages:
- (1) Even when the actuator device has a defective actuator, the displacement thereof can be compensated for by a normal actuator, thus eliminating a defective pixel.
- (2) The aperture ratio of a pixel can be increased.
- (3) One pixel can be turned on and off by the displacement of a plurality of actuators, and a region of maximum displacement in one actuator can be utilized for increased luminance and contrast.
- (4) The freedom of a pixel shape can be increased.
- The above and other objects, features, and advantages of the present invention will become more apparent from the following description of preferred embodiments in conjunction with the accompanying drawings.
-
FIG. 1 is a view showing an actuator device according to a first embodiment; -
FIG. 2 is a cross-sectional view showing a structural example of an actuator; -
FIG. 3 is a view showing an actuator device according to a second embodiment; -
FIG. 4 is a view showing a preferred form of the actuator devices according to the first and second embodiments; -
FIG. 5 is a view illustrative of the manner in which a displacement is compensated for when a second actuator of first and second actuators fails; -
FIG. 6 is a plan view showing an example of a structure for reducing the flexural rigidity of a vibrating section; -
FIG. 7 is a plan view showing another example of a structure for reducing the flexural rigidity of a vibrating section; -
FIG. 8 is a plan view of the structure shown inFIG. 7 ; -
FIG. 9 is a view showing a structure which employs electrostatic forces; -
FIG. 10 is a plan view of an example of a structure for increasing the flexural rigidity of a first plate member; -
FIG. 11 is a cross-sectional view taken along line XI-XI ofFIG. 10 ; -
FIG. 12 is a plan view of another example of a structure for increasing the flexural rigidity of a first plate member; -
FIG. 13 is a cross-sectional view showing an example of a structure in which the width of a portion of an actuator which is connected to a displacement transmitter is smaller than the width of a vibrating section; -
FIG. 14 is a cross-sectional view showing another example of a structure in which the width of a portion of an actuator which is connected to a displacement transmitter is smaller than the width of a vibrating section, and the width of a portion of a first plate member which is connected to the displacement transmitter is smaller than the width of the vibrating section; -
FIG. 15 is a cross-sectional view showing another example of a structure in which the width of a portion of a first plate member which is connected to a displacement transmitter is smaller than the width of a vibrating section; -
FIG. 16 is a view illustrative of operation of the structural example shown inFIG. 15 ; -
FIG. 17 is a cross-sectional view showing an example in which a vibrating section is of an arch shape; -
FIG. 18 is a cross-sectional view showing an example in which a vibrating section is of a wavy shape; -
FIG. 19 is a view illustrative of the manner in which a displacement is compensated for when a second actuator of first and second actuators fails; -
FIG. 20 is a perspective view showing a structural example in which a portion of a vibrating section has a wavy shape in the structure shown inFIG. 7 ; -
FIG. 21 is a plan view showing an example in which actuators are disposed at respective four corners of a first plate member; -
FIG. 22 is a cross-sectional view taken along line XXII-XXII ofFIG. 21 ; -
FIG. 23 is a plan view showing an example in which defect-compensating actuators are disposed in the structure shown inFIG. 21 ; -
FIG. 24 is a perspective view showing, with parts omitted from illustration, an example of joints interconnecting cells of a first plate member; -
FIG. 25 is a perspective view showing, with parts omitted from illustration, another example of joints interconnecting cells of a first plate member; -
FIG. 26A is a view showing a joint with a slit defined therein; -
FIG. 26B is a view showing a joint with a thinned portion; -
FIG. 27 is a perspective view showing, with parts omitted from illustration, a first plate member having a plurality of recesses defined in a lower surface thereof, and joints with slits defined therein; -
FIG. 28 is a perspective view showing, with parts omitted from illustration, an example of a structure in which four successive cells are grouped into a large cell with spacers associated with the large cell; -
FIG. 29 is a perspective view showing, with parts omitted from illustration, an example (grid shape) of a structure of spacers; -
FIG. 30 is a perspective view showing, with parts omitted from illustration, another example (stripe shape No. 1) of a structure of spacers; -
FIG. 31 is a perspective view showing, with parts omitted from illustration, another example (stripe shape No. 2) of a structure of spacers; -
FIG. 32 is a perspective view showing, with parts omitted from illustration, another example (columnar shape) of a structure of spacers; -
FIG. 33 is a view showing an actuator device according to a third embodiment; -
FIG. 34 is a view showing an actuator device according to a fourth embodiment; -
FIG. 35 is a view showing a display device according to a first specific example; -
FIG. 36 is an enlarged view showing an essential portion of the display device according to the first specific example, as viewed from an optical waveguide plate; -
FIG. 37 is a perspective view of a large-screen display device; -
FIG. 38 is a cross-sectional view showing a structure of actuator; -
FIG. 39A is a view showing a planar shape of a picture element assembly according to an inventive example; -
FIG. 39B is a view showing a planar shape of a picture element assembly according to a comparative example; -
FIG. 40 is a view illustrative of the difference between the displacements of actuators per pixel according to the comparative example; -
FIG. 41 is a view illustrative of the difference between the displacements of actuators per pixel according to the inventive example; -
FIG. 42 is a characteristic diagram showing luminance changes when a pixel is turned on and off, with respect to actuator defect ratios (the number of defective actuators/the number of actuators making up one pixel); -
FIG. 43 is a view of a joint plate with slits defined therein closely to spacers, as viewed from a reverse side of the joint plate; -
FIG. 44 is a view showing a display device according to a second specific example; -
FIG. 45 is a view showing a variable capacitor according to a specific example; -
FIG. 46 is a view showing a modification of the variable capacitor according to the specific example; -
FIG. 47 is a view showing an interference optical modulator according to a specific example; -
FIGS. 48A through 48C are cross-sectional views showing, with parts omitted from illustration, structural examples of mirror members; -
FIG. 49 is a view showing an actuator device according to a fifth embodiment; -
FIG. 50 is a view showing a first modification of the actuator device according to the fifth embodiment; -
FIG. 51 is a view showing a second modification of the actuator device according to the fifth embodiment; -
FIG. 52 is a view showing a conventional display device; and -
FIG. 53 is a plan view of the conventional display device as viewed from an optical waveguide plate thereof. - Embodiments of actuator devices according to the present invention will be described below with reference to
FIGS. 1 through 51 . - As shown in
FIG. 1 , anactuator device 10A according to a first embodiment has adrive section 16 including a plurality ofactuators 14 arranged in a plane on asubstrate 12, and afirst plate member 18 to which drive forces from theactuators 14 of thedrive section 16 are transmitted. - A plurality of
spacers 24 are disposed between thefirst plate member 18 and thesubstrate 12, forming mcells 15. N actuators 14 are assigned to each of thecells 15. Each of thecells 15 may have the same size (the cells serve as unit cells) or may have different sizes. - Each of the
actuators 14 comprises acavity 64, a vibratingsection 66, and a fixedsection 68 formed in thesubstrate 12. Of thesubstrate 32, a portion where thecavity 64 is defined is thin, and the other portion is thick. The thin portion is of a structure easily vibratable under external stresses and functions as the vibratingsection 66. The portion other than thecavity 64 is thick and functions as the fixedsection 68 supporting the vibratingsection 66. Adisplacement transmitter 76 for transmitting displacement of theactuator 14 to thefirst plate member 18 is interposed between the actuator 14 and thefirst plate member 18. - One structural example of the
actuator 14 will be described below with reference toFIG. 2 . Theactuator 14 has, in addition to the vibratingsection 66 and the fixedsection 68, anactuator body 75 comprising a piezoelectric/electrostrictive layer 72 directly formed on the vibratingsection 66, and a pair ofelectrodes electrostrictive layer 72. - The
electrodes electrostrictive layer 72, as shown inFIG. 2 , or on only one side thereof, or on only the upper side of the piezoelectric/electrostrictive layer 72. - If the
electrodes electrostrictive layer 72, then theelectrodes - In
FIGS. 1, 3 through 34, theactuator body 75 of theactuator 14 is omitted from illustration for the sake of brevity. - In the
actuator device 10A according to the first embodiment, drive forces from theactuators 14 arranged in a plane are transmitted to thefirst plate member 18. Since each of theactuators 14 is displaced vertically, thefirst plate member 18 is displaced in a direction substantially perpendicular to its plane. - The drive forces of the
actuators 14 may be produced by a generation source which comprises a piezoelectric element, an electrostatic force, a magnetic force, an electromagnetic force, a spring, a wire, or the like. - If a piezoelectric element is used as the generation source, then it may have a unimorph structure, a bimorph structure, a monomorph structure, a structure in which a piezoelectric actuator is formed on the vibrating
section 66, or a structure in which a piezoelectric actuator is formed on the vibratingsection 66 and the fixedsection 68. - If an electrostatic force is used as the generation source, then an electrode may be disposed on a surface of the vibrating
section 66 which faces the fixedsection 68 and an electrode may be disposed on a surface of the fixedsection 68 which faces the vibratingsection 66, and a voltage may be applied between the electrodes to generate an electrostatic force which displaces the vibrating section 66 (seeFIG. 9 ). Electrodes may be formed on the surface of the vibratingsection 66, or an insulator may be interposed between the different electrodes to prevent them from contacting each other and being short-circuited, or the surfaces of the electrodes may be covered with an insulator. - As shown in
FIG. 3 , anactuator device 10B according to a second embodiment is of substantially the same structure as theactuator device 10A according to the first embodiment, but differs therefrom in that it has separatefirst plate members 18 in alignment with therespective m cells 15. - Preferred forms of the
actuator devices FIGS. 4 through 24 . - The
first plate member 18 should preferably have a rigidity greater than the rigidity of the vibratingsections 66 of theactuators 14. - This feature will be described below with reference to
FIGS. 4 through 6 .FIG. 4 shows a structure in which a singlefirst plate member 18 is connected to two actuators (afirst actuator 14 a and asecond actuator 14 b) byrespective displacement transmitters 76. As shown inFIG. 6 , holes 170 may be defined in corresponding portions of the fixedsection 68 between thedisplacement transmitters 76 ofadjacent cells 15. -
FIG. 5 shows a state in which thesecond actuator 14 b fails and thefirst actuator 14 a is displaced to displace thefirst plate member 18 downwardly. Specifically, when thefirst actuator 14 a is displaced downwardly by a distance w0, thefirst plate member 18 tends to lower thesecond actuator 14 b downwardly, but thesecond actuator 14 b moves back a distance w1, due to a reactive force from the vibratingsection 66 of thesecond actuator 14 b. As a result, thefirst plate member 18 flexes the distance w1, and the vibratingsection 66 of thesecond actuator 14 b flexes a distance w2=w0- w1. - For simplified calculations, it is assumed that the centers of the vibrating
sections 66 of theactuators displacement transmitters 76 are aligned with each other, and concentrated loads are applied to the centers of the vibratingsections 66, and that displacements of thedisplacement transmitters 76 that are caused by such concentrated loads can be neglected. - As shown in
FIG. 5 , if it is assumed that the distance between thedisplacement transmitters 76 is represented by L1, the width of the vibratingsection 66 of thesecond actuator 14 b by L2, the flexural rigidity of thefirst plate member 18 by E1I1, and the flexural rigidity of the vibratingsections 66 by E2I2, then since the force (P) at the center of the vibratingsection 66 of thesecond actuator 14 b is in equilibrium, the following equations are satisfied:
w 1=PL 1 3/(3E 1 I 1) (1) cantilevered
w 2=PL 2 3/(48E 2 I 2) (2) supported at both ends - The ratio of w1, w2 is given as:
w 1/w 2=16×(L 1/L 2)3×(E 2 I 2/E 1 I 1) (3) - As the ratio w1/w2 is smaller, the displacement of the faulty
second actuator 14 b can be better compensated for. That is, as the flexural rigidity E1I1 of thefirst plate member 18 is greater than the flexural rigidity E2I2 of the vibratingsections 66 of the first andsecond actuators second actuator 14 b. - As shown in
FIGS. 7 and 8 , the vibratingsections 66 may extend in a cantilevered fashion from the fixedsection 68 into thecavity 64. In view of the concentrated load at the center (m) of thedisplacement transmitter 76 of thesecond actuator 14 b,
w 1=PL 1 3/(3E 1 I 1) (4) cantilevered
w 2=PL 2 3/(3E 2 I 2) (5) cantilevered - The ratio of w1, w2 is given as:
w 1/w 2=(L 1/L 2)3×(E 2 I 2/E 1 I 1) (6) - Since the structure shown in
FIGS. 7 and 8 is capable of reducing L1/L2, it is advantageous in that it can reduce the ratio w1/w2. - If the structure shown in
FIGS. 7 and 8 is employed, then as shown inFIG. 9 , for example, anelectrode 172 is formed on the lower surface of the vibratingsection 66 of thefirst actuator 14 a, anelectrode 174 is formed on the lower surface of the vibratingsection 66 of thesecond actuator 14 b, and anelectrode 176 facing theelectrode 172 and theelectrode 174 is formed on the bottom of thecavity 64, so that the first andsecond actuators second actuator 14 b, a voltage is applied between theelectrode 172 and theelectrode 176 to displace thefirst actuator 14 a downwardly, causing thefirst plate member 18 and thesecond actuator 14 b to be displaced downwardly. - As shown in
FIGS. 10 and 11 , the flexural rigidity of thefirst plate member 18 may be increased by providing a plurality ofgrooves 178 in the lower surface of thefirst plate member 18. Thegrooves 178 are formed (extend) in a direction in which theactuators 14 are arrayed. Thegrooves 178 have a depth which is 10% or more, preferably 30% or more, of the thickness of thefirst plate member 18. With this structure, the geometrical moment of inertia of thefirst plate member 18 is increased to increase the flexural rigidity of thefirst plate member 18. - As shown in
FIG. 12 , the flexural rigidity of thefirst plate member 18 may also be increased by providing a matrix or a staggered pattern ofconcavities 180 orconvexities 182. If theactuators 14 are displaced in a z-axis direction and thefirst plate member 18 has its plane lying in a xy-plane direction, then the above arrangement is suitable for increasing the flexural rigidity of thefirst plate member 18 in the case where two ormore actuators 14 are arrayed in each of x- and y-axis directions. The structure shown inFIG. 12 is effective in increasing geometrical moments of inertia in the x- and y-axis directions, thus increasing the flexural rigidity in all directions. The depth of theconcavities 180 and the height of theconvexities 182 are 10% or more, or preferably 30% or more, of the thickness of thefirst plate member 18. Theconcavities 180 and theconvexities 182 may have an X shape, a circular shape, a grid shape, a striped shape, a comb-toothed shape, or the like as viewed in plan, or may have a dimple shape, a saw-toothed shape, a peak shape, a wedge shape, a rectangular shape, or the like, as viewed in cross section. Theconcavities 180 and theconvexities 182 may be formed on both surfaces of thefirst plate member 18 or on one surface of thefirst plate member 18. Thefirst plate member 18 itself may be of a wavy shape. - The flexural rigidity of the
first plate member 18 may be made greater than the flexural rigidity of the vibratingsections 66 in terms of material and thickness. For example, if the vibratingsections 66 are made of zirconium oxide, then the Young's modulus thereof is 245.2 GPa, and if thefirst plate member 18 is made of stainless steel (e.g., SUS304), then the Young's modulus thereof is 193.0 GPa. If the cross section has a rectangular shape, then the geometrical moment of inertia is proportional to the cube of the thickness. Therefore, if the thickness of the vibratingsections 66 is 10 μm, for example, and the thickness of thefirst plate member 18 is 50 μm, for example, then the ratio of the flexural rigidities of thefirst plate member 18 and the vibratingsections 66 is 193.0×503/245.2×103=98.3. Therefore, the flexural rigidity of thefirst plate member 18 is greater than the flexural rigidity of the vibratingsections 66. - According to another preferred form, the width of a portion of the
actuator 14 which is joined to thedisplacement transmitter 76 is smaller than the width of the vibratingsection 66. Specific structural examples of this form are shown inFIG. 13 or 14, for example. - In
FIG. 13 , thedisplacement transmitter 76 is formed continuously over at least twoactuators surface having convexities 184 aligned respectively with theactuators actuators displacement transmitter 76 with respect to thefirst plate member 18, a contact width d2 of thedisplacement transmitter 76 with respect to the actuator (the vibrating section 66), and a width d3 of the vibratingsection 66 satisfy d1>d3>d2. If the vibratingsection 66 is regarded as a beam, then the width referred to above represents a value corresponding to the length of the beam. - In
FIG. 14 , thedisplacement transmitters 76 are formed separately from each other in alignment with therespective actuators actuators displacement transmitter 76 with respect to thefirst plate member 18, a contact width d2 of thedisplacement transmitter 76 with respect to the actuator (the vibrating section 66), and a width d3 of the vibratingsection 66 satisfy d3>d2=d1. - According to a next preferred form, the width of a portion of the
first plate member 18 which is joined to thedisplacement transmitter 76 is smaller than the width of the vibratingsection 66. Specific structural examples of this form are shown inFIG. 14 or 15, for example. - In
FIG. 15 , thedisplacement transmitter 76 is formed continuously over at least twoactuators surface having convexities 186 aligned respectively with theactuators actuators displacement transmitter 76 with respect to thefirst plate member 18, a contact width d2 of thedisplacement transmitter 76 with respect to the actuator (the vibrating section 66), and a width d3 of the vibratingsection 66 satisfy d1<d3=d2. The structure shown inFIG. 10 has been described above, and will not be described below. - With the structure shown in
FIG. 15 , as shown inFIG. 16 , when thefirst actuator 14 a is displaced downwardly, thesecond actuator 14 b which suffers a failure can also be displaced. - With the
actuator devices actuators 14 become defective, their displacement can be compensated for by thenormal actuators 14. Therefore, the yield of the actuator devices is increased. Furthermore, the area of a portion that is displaced by theactuator 14, i.e., an effective area, can be increased. - Particularly, since the rigidity of the
first plate member 18 is greater than the rigidity of the vibratingsections 66 of theactuators 14, even when oneactuator 14 fails due to cracking or wire breakage, thefirst plate member 18 is displaced when anotheractuator 14 is displaced, producing forces to displace the vibratingsection 66 of thefaulty actuator 14. Consequently, even in the event of a failure of oneactuator 14, the displacement of the entirefirst plate member 18 is not affected thereby, making it possible to compensate for the faulty region. Since theactuators 14 have the vibratingsections 66, any faulty actuator can easily be displaced under external forces. Such defect compensation cannot be obtained by a laminated actuator, for example, which does not have the vibratingsections 66. - The flexural rigidity of the
first plate member 18 should be 10 times the flexural rigidity of the vibratingsections 66 or greater. This reduces the amount of flexing of thefirst plate member 18. In this case, there is obtained a structure which is less susceptible to manufacturing irregularities with respect to the distance between theactuators 14 and the size of thedisplacement transmitter 76. - Since the
first plate member 18 has thegrooves 178, theconcavities 180, and theconvexities 182, the geometrical moment of inertia of thefirst plate member 18 can be increased, and the flexural rigidity of thefirst plate member 18 can be increased. Because the rigidity can be increased with a small amount of material, they are effective in reducing the weight of the actuator device. Inasmuch as the inertial mass is reduced, the response speed of the actuators is increased. - In the process of displacing the
actuators 14, it is preferable for the distance between the vibratingsections 66 and thefirst plate member 18 to remain substantially unchanged. For example, if thedisplacement transmitter 76 is interposed between the vibratingsections 66 and thefirst plate member 18, then it is preferable that the thickness (height) of thedisplacement transmitter 76 be not essentially changed by the displacement of the actuators 14 (not subject to compressive deformation, tensile deformation, and buckling deformation). In this case, compressive deformation and tensile deformation can be reduced by adding a filler to thedisplacement transmitter 76. - Furthermore, as the width of a portion of the
actuator 14 which is joined to thedisplacement transmitter 76 is smaller than the width of the vibratingsection 66, the displacement of the vibratingsection 66 and forces produced thereby can reliably be transmitted to thefirst plate member 18 by thedisplacement transmitter 76. With the forms shown inFIGS. 13 through 15 , in particular, the actuator device may be arranged not to obstruct the displacement of thedisplacement transmitter 76, and with the forms shown inFIGS. 13 and 14 , the actuator device may be arranged such that thedisplacement transmitter 76 does not overlap the fixedsection 68. In these cases, thedisplacement transmitter 76 should preferably be not too small with respect to the vibratingsection 66 so that the vibratingsection 66 and thefirst plate member 18 are reliably fixed to each other. As the displacement and generated forces differ depending on the location of the vibratingsection 66, even if the joint between the vibratingsection 66 and thedisplacement transmitter 76 does not include a portion of the vibratingsection 66 which causes the largest displacement, optimum values can be obtained from generated forces and a required amount of displacement. Specifically, the width of thedisplacement transmitter 76 should be in the range from 5% to 99%, or preferably in the range from 30% to 90%, of the width of the vibratingsection 66. In terms of areas, the cross-sectional area of thedisplacement transmitter 76 should be in the range from 0.5% to 99%, or preferably in the range from 10% to 90%, of the cross-sectional area of the vibratingsection 66. The ratio of the height to width of thedisplacement transmitter 76, i.e., the aspect ratio of thedisplacement transmitter 76, should be smaller than 1, or preferably smaller than 0.2. - If the rigidity of the vibrating
section 66 is greater than the rigidity of thefirst plate member 18, then thefirst plate member 18 tends to flex without displacing the vibratingsection 66 of afaulty actuator 14, and thefirst plate member 18 includes a portion which is displaced and a portion which is not displaced. Therefore, such a rigidity setting is not preferable. - In the form shown in
FIG. 4 , the vibratingsections 66 are flat. However, as shown inFIG. 17A , the vibratingsections 66 may be of an arch shape, or as shown inFIG. 18 , the vibratingsections 66 may be of a wavy shape. In the examples shown inFIGS. 17A and 18 , the vibratingsections 66 are convex toward thefirst plate member 18. The vibratingsections 66 that are convex toward thefirst plate member 18 are more effective to increase the response of theactuators 14 than if the vibratingsections 66 are not of a convex shape (e.g., they are flat), and allowadjacent actuators 14 to compensate for displacement even if anactuator 14 fails. - The reasons for the above advantages are as follows: In the presence of the
first plate member 18, the vibratingsections 66 need to displace a large mass, and undergoes a larger load than if it were not for thefirst plate member 18. Since the vibratingsections 66 are of a convex shape, their drive forces become stronger to keep response at a higher level. The rigidity is increased to sufficiently bear the mass of thefirst plate member 18 that is applied to the vibratingsections 66. - In the event of a failure of an
actuator 14, thefirst plate member 18 driven by theadjacent actuators 14 displaces the vibratingsection 66. At this time, it is desirable that reactive forces from the vibratingsection 66 be small. The convex shape is considered to have such characteristics that it increases drive forces but prevents reactive forces from increasing when displaced by thefirst plate member 18. - The structure in which the vibrating
sections 66 are of a convex shape is particularly preferably used in an arrangement wherein the vibratingsections 66 have both ends connected to the fixedsection 68 and an arrangement wherein the peripheral region of the vibrating sections is connected to the fixedsection 68. If cavities are present below the vibratingsections 66, then the cavities may be filled with a liquid. In such a case, the peripheral region of the vibratingsections 66 needs to be connected to the fixedsection 68 to prevent the liquid from leaking. - In the event of a failure of an
actuator 14, thefirst plate member 18 is displaced by anormal actuator 14, and the vibratingsection 66 of thefaulty actuator 14 is depressed by thedisplacement transmitter 76. If the vibratingsection 66 whose peripheral region is connected to the fixedsection 68 is of a flat cross-sectional shape, then forces tending to obstruct the displacement are liable to increase under the tension of the vibratingsection 66 which is kept taut. This is because the vibratingsection 66 is extended in its longitudinal direction for producing the above displacement. If the vibratingsection 66 is of an arch or wavy shape, then since the vibratingsection 66 itself has a larger length than the minimum distance between its joints to the fixedsection 68, forces tending to obstruct the displacement are relatively weak when the vibratingsection 66 undergoes forces from thedisplacement transmitter 76. - If the vibrating
section 66 is of an arch shape, then when theactuator 14 is displaced under drive forces in a direction away from thefirst plate member 18, the vibratingsection 66 should preferably have an arch shape that is convex toward thefirst plate member 18. When theactuator 14 is displaced under drive forces in a direction toward thefirst plate member 18, the vibratingsection 66 should preferably have an arch shape that is concave toward thefirst plate member 18. - If the
actuator 14 in which the vibratingsection 66 is convex toward thefirst plate member 18 is displaced toward thefirst plate member 18, then the length of the vibratingsection 66 is increased and forces tending to obstruct the displacement thereof are increased. When theactuator 14 in which the vibratingsection 66 is convex toward thefirst plate member 18 undergoes forces applied in a direction away from thefirst plate member 18 through thedisplacement transmitter 76, theactuator 14 is displaced as the vibratingsection 66 flexes. - With the vibrating
section 66 fixed at its both ends or peripheral region to the fixedsection 68, since the rigidity of the vibratingsection 66 is not too high, the actuator device is highly effective to perform compensation for a failure. The degree of freedom for design is also increased. The vibratingsection 66 may also be fixed at one end to the fixedsection 68. - If the vibrating
section 66 is of an arch shape or a wavy shape, the height (or depth) of the convexity (or concavity) thereof toward thefirst plate member 18 should preferably be greater than the height (or depth) corresponding to the thickness of the vibratingsection 66. - For keeping the responsiveness of the
actuator 14, the rigidity of the vibratingsection 66 needs to be not too small and should naturally be selected in view of the thickness, width, beam length, shape, material, etc. of the vibratingsection 66. The convexity or concavity of the convex shape does not have to be formed in the central region of the vibratingsection 66. - As shown in
FIGS. 17A and 18 , the convex shape of the vibratingsection 66 may be formed in the longitudinal direction of the beam. Alternatively, as shown inFIG. 20 , the convex shape of the vibratingsection 66 may be formed in a direction parallel to the joint between the vibratingsection 66 and the fixedsection 68. Particularly, the vibratingsection 66 should preferably be of a wing shape (W shape) in the longitudinal direction of the beam. InFIG. 20 , the arrows A indicate that the vibratingsection 66 is deformed in a convex shape. If the vibratingsection 66 has a wing shape, the width of the convex shape, i.e., the distance between valleys, should preferably be ⅓ of the beam length or greater. If the vibratingsection 66 is convex toward thefirst plate member 18, then the vertex of the convex shape should preferably project toward thefirst plate member 18 beyond the height of the fixedsection 68. - As shown in
FIGS. 21 and 22 , onefirst plate member 18 may be provided in combination with fouractuators 14 arranged in a matrix. In this case, theactuators 14 should preferably be disposed at the respective four corners of thefirst plate member 18. With this arrangement, it is possible to control the displacement of thefirst plate member 18 having a large area with a small number ofactuators 14 having a small area, and the area of a portion that is displaced by theactuators 14, i.e., an effective area (an aperture ratio if the actuator device is applied to a display apparatus, or the like), can be increased. This leads to low electric power consumption and an increase in the rigidity of thesubstrate 12, and stabilization of the planar shape. - As shown in
FIG. 23 ,actuators 14 may be disposed at the respective four corners of thefirst plate member 18, and defect-compensatingactuators 14 e may be disposed on the diagonal lines of thefirst plate member 18 adjacent to therespective actuators 14 for greatly increased reliability. - The
actuator devices cells 15 arranged in a plane. Particularly, the first plate member of theactuator device 10A according to the first embodiment has interconnected portions corresponding to therespective cells 15, as shown inFIGS. 24 and 25 . The rigidity of all or some ofjoints 190 interconnecting thecells 15 is smaller than the rigidity of portions 192 (hereinafter referred to as cell portions) of thefirst plate member 18 which correspond to therespective cells 15. - The rigidity of all or some of the
joints 190 of thefirst plate member 18 may be made smaller than the rigidity of thecell portions 192 by formingslits 194 or the like in thejoints 190 to make the width (2×D2) of thejoints 190 smaller than the width D1 of thecell portions 192, as shown inFIG. 26A , or by makingportions 196 of thejoints 190 thinner than thecell portions 192, as shown inFIG. 26B . - In the embodiment shown in
FIG. 24 ,slits 194 are formed in portions of thefirst plate member 18 which correspond to the spacers 24 (spacer portions 220), and thecell portions 192 and thespacer portions 220 are joined bynarrow arms 222. - In the embodiment shown in
FIG. 25 , a plurality ofvertical rule portions 224 and a plurality ofhorizontal rule portions 226 which extend respectively vertically and horizontally along the array ofspacers 24 are joined by thespacer portions 220, and thehorizontal rule portions 226 and thecell portions 192 are joined bynarrow arms 222. Thus, slits 194A along thevertical rule portions 224 and slits 194B along thehorizontal rule portions 226 are formed in thefirst plate member 18. - According to a specific process, as shown in
FIG. 27 , one surface (e.g., lower surface) of thefirst plate member 18 is half-etched to a depth which is half the thickness of thefirst plate member 18, thereby forming a plurality ofrecesses 180 in thecell portions 192. At this time, thejoints 190 between thecell portions 192 and portions where slits are to be formed are also half-etched to form recesses 198. Then, portions where slits are to be formed on the opposite surface (e.g., upper surface) are etched to form holes in the portions where slits are to be formed, thereby forming slits 194. - Of the
first plate member 18, each of thecell portions 192 has its geometrical moment of inertia increased by therecesses 180, and hence has increased flexural rigidity. Thejoints 190 have their thickness reduced to about half by therecesses 198, and also have their width reduced by theslits 194. Therefore, the flexural rigidity of thejoints 190 is smaller than thecell portions 192. - In the
actuator device 10A according to the first embodiment, as shown inFIG. 24 , for example, as thejoints 190 of thefirst plate member 18 and the fixed sections 68 (seeFIG. 1 ) are joined by thespacers 24, the distance between thecell portions 192 of thefirst plate member 18 and the fixedsections 68 can be established accurately and reliably. - In particular, the
spacers 24 that are present between thesubstrate 12 and thejoints 190 of thefirst plate member 18 offer the following advantages: - If the
substrate 12 has different heights depending on the location, e.g., if thesubstrate 12 has undulations (which are often unavoidable in the manufacturing process) when a plurality ofactuators 14 are to be formed on onesubstrate 12, the distance between thesubstrate 12 and thefirst plate member 18 disposed above thesubstrate 12 varies depending on the location, possibly resulting in direct contact between theactuators 14 and thefirst plate member 18. In this case, thefirst plate member 18 is partly strained, tending to fail to operate thefirst plate member 18 as desired with theactuators 14. - The
spacers 24 that are present between thesubstrate 12 and thejoints 190 of thefirst plate member 18 do not give rise to the above problem even if thesubstrate 12 has undulations because the distance between thefirst plate member 18 and thesubstrate 12 is maintained by thespacers 24. - The
actuators 14 that are connected to thefirst plate member 18 have their displacement characteristics affected thereby. As the distance between thefirst plate member 18 and thesubstrate 12 is determined by thespacers 24, the degree of a change in the displacement characteristics of theactuators 14 is kept constant irrespective of the location, and thespacers 24 are highly effective to prevent the displacement characteristics from varying. For example, since the thickness of the connectors (e.g., the displacement transmitters 76) which connect theactuators 14 and thefirst plate member 18 is uniformized, the effect thereof on the displacement characteristics of theactuators 14 is uniformized. - In the absence of the
spacers 24, when theactuators 14 and thefirst plate member 18 are partly displaced considerably closely to each other, thedisplacement transmitters 76 tend to spread more greatly than the size of theactuators 14, possibly impairing operation of theactuators 14. This drawback can be avoided by adding thespacers 24. - If the height of the
spacers 24 is greater than necessary, then shortcomings such as characteristic changes are liable to occur due to expansion or shrinkage of thespacers 24 themselves and an increase in the load on theactuators 14. Thespacers 24 can sufficiently be made effective by setting thespacers 24 to an appropriate height. - The
spacers 24 should be arranged such that they are associated with therespective cells 15, as shown in FIG. 24. This is because thespacers 24 can firmly be fixed, and the distance between thecell portions 192 and the fixedsections 68 can accurately and reliably be established. If the effective areas of thecell portions 192 are reduced due to thespacers 24 associated with therespective cells 15, then for the purpose of increasing the effective area efficiency, as shown inFIG. 28 , foursuccessive cells 15 are grouped into onelarge cell 200, andspacers 24 may be associated with eachlarge cell 200.Spacers 24 may be provided on only the outer circumference of theactuator device 10A. - As shown in
FIG. 29 ,spacers 24 may be formed in a grid pattern so as to surroundcells 15. Alternatively, spacers 24 may be formed in a striped pattern along confronting sides ofcells 15. As shown inFIG. 24 ,columnar spacers 24 may be disposed on the four corners ofcells 15, or as shown inFIG. 32 ,columnar spacers 24 may be disposed on the four sides ofcells 15. - As shown in
FIG. 33 , an actuator device 10C according to a third embodiment is of substantially the same structure as the actuator device according to the first embodiment, but differs therefrom in that it has asecond plate member 20 disposed facing thefirst plate member 18. - A plurality of
spacers 22 are formed between thefirst plate member 18 and thesecond plate member 20, forming mcells 15, for example. - As shown in
FIG. 34 , anactuator device 10D according to a fourth embodiment is of substantially the same structure as theactuator device 10B according to the second embodiment, but differs therefrom in that thefirst plate member 18 is divided into segments corresponding to them cells 15. A plurality ofspacers 26 are interposed between thesecond plate member 20 and thesubstrate 12 in gaps between adjacent ones of thefirst plate members 18. - The
actuator devices 10A through 10D according to the first through fourth embodiments described above are applicable to a display device, and also applicable to a variable capacitor, an optical modulator, or the like. -
Display devices actuator devices 10C, 10D according to the third and fourth embodiments are applied, will be described below with reference toFIGS. 35 through 44 . - As shown in
FIG. 35 , thedisplay device 30A according to the first specific example has adrive section 36 including a plurality ofactuators 34 arranged in a plane (e.g., a matrix or staggered pattern) on anactuator substrate 32, a singleoptical waveguide plate 38 which is disposed facing theactuator substrate 32 and into which light 33 from a light source is introduced from an end face thereof, and a singlejoint plate 40 which is disposed between theactuator substrate 32 and theoptical waveguide plate 38 and to which drive forces from theactuators 34 of thedrive section 36 are transmitted. - As shown in
FIG. 36 , a plurality ofspacers 42 are formed between theactuator substrate 32 and thejoint plate 40 surroundingcells 50 which form respective pixels (pixel forming zones). A plurality ofspacers 44 are also formed between thejoint plate 40 and theoptical waveguide plate 38 surrounding thecells 50. - Each of the
cells 50 is separated in a rectangular shape, for example, byplural spacers picture element assembly 52 is formed on thejoint plate 40 in association with eachcell 50. In the present embodiment, onepicture element assembly 52 on thejoint plate 40 is assigned to sixactuators 34 on theactuator substrate 32. - A plurality of
display devices 30A according to the first specific example are arranged in a matrix on the back of a singlelight guide plate 60, as shown inFIG. 37 , thus providing a single large-screen display device 62. - The large-
screen display device 62 has a matrix ofdisplay devices 30A, five in a horizontal direction and four in a vertical direction, on the back of thelight guide plate 60, such that 640 pixels are arrayed in the horizontal direction and 480 pixels are arrayed in the vertical direction, in order to comply with VGA (Video Graphics Array) standards, for example. - The
light guide plate 60 comprises a glass plate, an acrylic plate, or the like whose light transmittance is large and uniform in the visible range. The displacedevices 30A are connected by wire bonding, soldering, end-face connectors, reverse-side connectors, etc. for supplying signals therebetween. - The
light guide plate 60 and theoptical waveguide plates 38 of thedisplay devices 30A should preferably have similar refractive indexes. If thelight guide plate 60 and theoptical waveguide plates 38 are bonded to each other, then a transparent adhesive or liquid may be used to bond them together. Such a transparent adhesive or liquid should preferably have a uniform and high light transmittance in the visible range, like thelight guide plate 60 and theoptical waveguide plates 38, and a refractive index close to those of thelight guide plate 60 and theoptical waveguide plates 38 for achieving screen brightness. - In the above embodiment, the surfaces of the
optical waveguide plates 38 of thedisplay devices 30A are bonded to thelight guide plate 60, making up the large-screen display device 62. As indicated by the parentheses inFIG. 37 , theoptical waveguide plates 38 may be dispensed with, the end faces of the spacers 44 (seeFIG. 35 ) may be directly bonded to thelight guide plate 60, making up the large-screen display device 62. - The
actuator substrate 32 of thedisplay device 30A hascavities 64 defined therein at positions in alignment with therespective actuators 34 and forming vibratingsections 66 to be described later. Thecavities 64 communicate with the exterior through small-diameter through holes (not shown) defined in the other end of theactuator substrate 32. - Of the
actuator substrate 32, portions where thecavities 64 are defined are thin, and the other portions are thick. The thin portions are of a structure easily vibratable under external stresses and function as the vibratingsections 66. The portions other than thecavities 64 are thick and function as fixedsections 68 supporting the vibratingsections 66. - As shown in
FIG. 38 , theactuator substrate 32 comprises a laminated assembly of asubstrate layer 32A as a lowermost layer, aspacer layer 32B as an intermediate layer, and athin layer 32C as an uppermost layer, and can be recognized as a unitary structural body in which thecavity 64 is defined in the portion of thespacer layer 32B that corresponds to theactuator 34. Thesubstrate layer 32A functions as a stiffening substrate and also as a wiring substrate. Theactuator substrate 32 may be integrally sintered or may subsequently be added. - The
substrate layer 32A, thespacer layer 32B, and thethin layer 32C may be made of a material which is highly resistant to heat, highly strong, and highly tough, e.g., stabilized zirconium oxide, partially stabilized zirconium oxide, aluminum oxide, magnesium oxide, titanium oxide, spinel, mullite, or the like. Thesubstrate layer 32A, thespacer layer 32B, and thethin layer 32C may be made of one material or different materials. - The
thin layer 32C has a thickness of 50 μm or preferably in the range from 3 μm to 20 μm for allowing theactuator 34 to be displaced largely. - The
spacer layer 32B may be present as providing thecavities 64 in theactuator substrate 32, and is not limited to any thickness. However, the thickness of thespacer layer 32B may be determined depending on the purpose for which thecavities 64 are used. It is preferable that thespacer layer 32B do not have a thickness greater than necessary for theactuator 34 to function, and should be thin. That is, the thickness of thespacer layer 32B should preferably be as large as the displacement of theactuator 34. - With this arrangement, the flexing of the thin portion (the vibrating section 66) is limited by the
substrate layer 32A which is close thereto in the direction in which the thin portion flexes, and the thin portion is prevented from being broken under unintended external forces applied thereto. It is possible to stabilize the displacement of theactuator 34 at a particular value by using the ability of thesubstrate layer 32A to limit the flexing of the thin portion. - Since the thickness of the
actuator substrate 32 itself and its flexural rigidity can be reduced by thinning thespacer layer 32B, when theactuator substrate 32 is bonded and fixed to a separate body, buckling or the like of theactuator substrate 32 with respect to the separate body (e.g., theoptical waveguide plate 38 or the joint plate 40) can effectively be corrected for increased bonding and fixing reliability. - In addition, as the
entire actuator substrate 32 is thin, the amount of material used to manufacture theactuator substrate 32 is reduced. This structure is therefore advantageous also from the standpoint of manufacturing cost. Specifically, the thickness of thespacer layer 32B should preferably in the range from 3 μm to 50 μm and more preferably in the range from 3 μm to 20 μm. - Because the
spacer layer 32B is thin, the thickness of thesubstrate layer 32A is equal to or greater than 50 μm, preferably in the range from 80 μm to 300 μm, for the purpose of reinforcing theentire actuator substrate 32. - A specific example of the
actuator 34 and thepicture element assembly 52 will be described below with reference toFIGS. 35 and 38 .FIG. 35 shows a structure in which light shield layers 70 are disposed between thespacers 44 interposed between theoptical waveguide plate 38 and thejoint plate 40 and theoptical waveguide plate 38. - As shown in
FIG. 38 , theactuator 34 has, in addition to the vibratingsection 66 and the fixedsection 68, anactuator body 75 comprising a piezoelectric/electrostrictive layer 72 directly formed on the vibratingsection 66, and a pair ofelectrodes electrostrictive layer 72. - The
electrodes electrostrictive layer 72, as shown inFIG. 38 , or on only one side thereof, or on only the upper side of the piezoelectric/electrostrictive layer 72. - If the
electrodes electrostrictive layer 72, then theelectrodes - The
electrodes electrodes actuator substrate 32 and/or the same material as a piezoelectric/ electrostrictive material to be described below is dispersed. - The
electrodes actuator substrate 32 by a film forming process such as photolithography, screen printing, dipping, coating, electrophoresis, ion beam process, sputtering, vacuum evaporation, ion plating, chemical vapor deposition (CVD), plating, etc. - Preferred materials that can be used for the piezoelectric/electrostrictive material include lead zirconate, lead manganese tungstenate, bismuth sodium titanate, bismuth ferrate, sodium potassium niobate, bismuth strontium tantalate, lead magnesium niobate, lead nickel niobate, lead zinc niobate, lead manganese niobate, lead magnesium tantalate, lead nickel tantalate, lead antimony tinate, lead titanate, barium titanate, barium copper tungstenate, lead magnesium tungstenate, lead cobalt niobate, or a composite oxide comprising at least two of the above compounds. The piezoelectric/electrostrictive material may contain a solid solution of an oxide of lanthanum, calcium, strontium, molybdenum, tungsten, barium, niobium, zinc, nickel, manganese, cerium, cadmium, chromium, cobalt, antimony, iron, yttrium, tantalum, lithium, bismuth, tin, copper, etc.
- An antiferroelectric layer may be used in place of the piezoelectric/
electrostrictive layer 72. In this case, lead zirconate, a composite oxide of lead zirconate and lead tinate, or a composite oxide of lead zirconate, lead tinate, and lead niobate may be used. These antiferroelectric materials may contain a solid solution of the above elements. - A material produced by adding lithium bithmuthate, lead germanate, or the like to the above material, e.g., a material produced by adding lithium bithmuthate or lead germanate to a composite oxide of lead zirconate, lead titanate, and lead magnesium niobate, is preferable because it allows the piezoelectric/
electrostrictive layer 72 to be sintered at a low temperature and achieve high material characteristics. The piezoelectric/electrostrictive layer 72 can also be sintered at a low temperature by adding glass (e.g., silicate glass, borate glass, phosphate glass, germanate glass, or a mixture thereof). However, since excessively adding the glass would invite deterioration of material characteristics, it is desirable to determine an amount of glass to be added depending on the required characteristics. - As a pair of
electrodes electrode 74 a is formed on the lower surface of the piezoelectric/electrostrictive layer 72 and theelectrode 74 b is formed on the upper surface of the piezoelectric/electrostrictive layer 72, as shown inFIG. 38 , then it is possible to flexurally displace theactuators 34 in one direction so as to be convex toward thecavities 64, as shown inFIG. 35 , or alternatively it is possible to flexurally displace theactuators 34 in the other direction so as to be convex toward thejoint plate 40. - The opening width (area) of the
cavity 64 should preferably be larger than the width (area) of theactuator body 75. However, the opening width (area) of thecavity 64 may be equal to or slightly smaller than the width (area) of theactuator body 75. - A
displacement transmitter 76 for transmitting displacement of theactuator 34 to thejoint plate 40 is disposed above theactuator 34. Thedisplacement transmitter 76 may comprise an adhesive which may be a filler-containing adhesive. Thejoint plate 40 and the end face of thedisplacement transmitter 76 may be fixed (joined) to each other, or may simply be held in contact with each other. The term “connect” will be used below as covering “fix” and “contact”. Thus, theactuator 34 and thejoint plate 40 are connected to each other by thedisplacement transmitter 76. - The
displacement transmitter 76 is not limited to any material, but may preferably be made of thermoplastic resin, thermosetting rein, photosetting resin, moisture-absorption-setting resin, cold-setting resin, or the like. - Specifically, acrylic resin, modified acrylic resin, epoxy resin, modified epoxy resin, silicone resin, modified silicone resin, vinyl acetate resin, ethylene-vinyl acetate copolymer resin, vinyl butyral resin, cyanoacrylate resin, urethane rein, polyimide resin, metacryl resin, modified metacryl resin, polyolefin resin, special silicone modified polymer, polycarbonate resin, natural rubber, synthetic rubber, etc. are given by way of example.
- Particularly, vinyl butyral resin, acrylic resin, modified acrylic resin, epoxy resin, modified epoxy resin, or a mixture of two or more of these resins is preferable for their excellent bonding strength. Among others, epoxy resin, modified epoxy resin, or a mixture thereof is preferable.
- The
joint plate 40 is of a material and thickness for providing an optimum rigidity to compensate for the displacement of an actuator which fails to be displaced (defective actuator) due to the displacement of anormal actuator 34 that is connected to thejoint plate 40. - Specifically, the
joint plate 40 may be made of a metal, ceramics, glass, or an organic resin, but is not limited to any particular materials insofar as they are capable of the functions thereof as described above. For example, SUS304 (Young's modulus: 193 GPa, coefficient of linear expansion: 17.3×10−6/C°), SUS403 (Young's modulus: 200 GPa, coefficient of linear expansion: 10.4×10−6/C°), zirconium oxide (Young's modulus: 245.2 GPa, coefficient of linear expansion: 9.2×10−6/C°), and glass (e.g., Corning 0211, Young's modulus: 74.4 GPa, coefficient of linear expansion: 7.38×10−6/C°) are preferably used. In the present embodiment, thejoint plate 40 comprises an SUS plate having a thickness preferably in the range from 10 μm to 300 μm. - The
spacers - A filler may be contained in the
spacers spacers display device 30A. Stated otherwise, the hardness, heat resistance, and strength of the set resin can be increased and the amount by which it thermally expands and shrinks can be greatly reduced by including a filler in the spacers. - As shown in
FIG. 35 , thepicture element assembly 52 may comprise a laminated assembly of alight scattering layer 78 and atransparent layer 80 that are formed on thejoint plate 40. - The
picture element assembly 52 may comprise, in addition to the laminated assembly, any of various combinations including (1) a color filter or a colored scattering body interposed between thetransparent layer 80 and thelight scattering layer 78, (2) a light reflecting layer disposed beneath thelight scattering layer 78, and (3) a laminated assembly of a colored scattering body and thetransparent layer 80. - The formation of films such as the
electrodes electrostrictive layer 72, and thespacer 42 on theactuator substrate 32, and the formation of films such as thepicture element assembly 52 and thespacer 44 on thejoint plate 40 are not limited to any processes, but may be performed by various known film formation processes. - For example, films may be grown on the surfaces of the
actuator substrate 32 and thejoint plate 40 by a film applying process which directly applies a chip-like or web-like film, a thick-film forming process such as a screen printing process, a photolithographic process, a spray dipping process, or a coating process, or a thin-film forming process such as an ion beam process, a sputtering process, a vacuum evaporation process, an ion plating process, a chemical vapor deposition (CVD) process, a plating process, or like, which applies a powder, a paste, a liquid, a gas, ions, or the like as a raw material of a film. - Operation of the
display device 30A will briefly be described below with reference toFIGS. 35 and 38 . First, light 33 is introduced into theoptical waveguide plate 38 from an end thereof, for example. With thepicture element assemblies 52 held out of contact with theoptical waveguide plate 38, all of the light 33 is totally reflected within theoptical waveguide plate 38 without passing through front and back surfaces thereof by adjusting the magnitude of the refractive index of theoptical waveguide plate 38. The refractive index of theoptical waveguide plate 38 is desirably in the range from 1.3 to 1.8, or more desirably in the range from 1.4 to 1.7. - In this example, when the
actuators 34 are in a natural state, since the end faces of thepicture element assemblies 52 contact the back of theoptical waveguide plate 38 by a distance equal to or smaller than the wavelength of the light 33, the light 33 is reflected by the surfaces of thepicture element assemblies 52 as scatteredlight 82. Thescattered light 82 is partly reflected within theoptical waveguide plate 38, but mostly passes through the front face (surface) of theoptical waveguide plate 38 without being reflected by theoptical waveguide plate 38. Therefore, all of theactuators 34 are turned on, emitting light whose color corresponds to the color of the color filters and light scattering layers 78 included in thepicture element assemblies 52. As the pixels corresponding to all theactuators 34 are turned on, white light is displayed on the screen of thedisplay device 30A. - Furthermore, a low-level voltage (e.g., −10 V) is applied as a drive voltage between the
electrodes actuators 34 to press the end faces of thepicture element assemblies 52 against the back of theoptical waveguide plate 38 for more reliably turning on theactuators 34 for stable display. - When a high-level drive voltage (e.g., 50 V) is then applied between the
electrodes actuators 34 corresponding to a certain pixel, those sixactuators 34 are flexurally displaced as to be convex toward thecavities 64, i.e., flexurally displaced downwardly, as shown inFIG. 35 . Consequently, the drive displacement is transmitted through thedisplacement transmitters 76 and thejoint plate 40 to thepicture element assembly 52. The end face of thepicture element assembly 52 is now spaced from theoptical waveguide plate 38. The pixel corresponding to thepicture element assembly 52 is turned off, extinguishing the light emission. - Therefore, the
display device 30A can control whether there is light emission (scattered light 82) on the front face of theoptical waveguide plate 38 or not based on whether thepicture element assemblies 52 contact theoptical waveguide plate 38 or not. - One frame ( 1/60 sec.) of pixel signals is divided into three times zones (first through third fields), and three-color light sources are switched in each field. For example, light from a red-color light source (R light source) is introduced in the first field, light from a green-color light source (G light source) is introduced in the second field, and light from a blue-color light source (B light source) is introduced in the third field to display a color image with the monochromatic pixel array. In this case, since one
picture element assembly 52 provides one pixel, a high resolution can be achieved. - The materials of the major structural components of the
display device 30A according to the first specific example have been described above. Materials of other structural components (the light 33, theactuator substrate 32, and the optical waveguide plate 38) will be described below. - The light 33 that is applied to the
optical waveguide plate 38 may be in either one of ultraviolet, visible, and infrared ranges. The light source thereof may be an incandescent lamp, a heavy-hydrogen discharge lamp, a fluorescent lamp, a mercury lamp, a metal halide lamp, a halogen lamp, a xenon lamp, a tritium lamp, a light-emitting diode, a laser, a plasma light source, a hot-cathode tube, a cold-cathode tube, or the like. - The vibrating
section 66 should preferably be made of a highly heat-resistant material. The reason for this is that if the vibratingsection 66 is directly supported by the fixedsection 68 without using a heat-resistant material such as an organic adhesive or the like, the vibratingsection 66 should preferably be made of a highly heat-resistant material in order to prevent itself from being modified when at least the piezoelectric/electrostrictive layer 72 is formed. - The vibrating
section 66 should preferably be made of an electrically insulating material in order to electrically isolate an interconnection (e.g., a row selection line) connected to oneelectrode 74 a of theelectrodes actuator substrate 32 from an interconnection (e.g., a signal line) connected to theother electrode 74 b. - Therefore, the vibrating
section 66 may thus be made of a material such as an enameled material where a highly heat-resistant metal or its surface is covered with a ceramic material such as glass or the like. However, ceramics is optimum as the material of the vibratingsection 66. - The ceramics of the vibrating
section 66 may be stabilized zirconium oxide, aluminum oxide, magnesium oxide, titanium oxide, spinel, mullite, aluminum nitride, silicon nitride, glass, or a mixture thereof. Stabilized zirconium oxide is particularly preferable because it has high mechanical strength, high tenacity, and causes a relatively small chemical reaction with the piezoelectric/electrostrictive layer 72 and theelectrodes section 66 is thin. Stabilized zirconium oxide includes both stabilized zirconium oxide and partially stabilized zirconium oxide. Stabilized zirconium oxide does not cause a phase transition because it has a crystalline structure such as a cubic structure or the like. - Zirconium oxide causes a phase transition between a monoclinic structure and a tetragonal structure at about 1000° C., and may crack upon such a phase transition. Stabilized zirconium oxide contains 1-30 mol % of calcium oxide, magnesium oxide, yttrium oxide, scandium oxide, ytterbium oxide, sodium oxide, or an oxide of a rare earth metal. The stabilizer should preferably contain yttrium oxide for increasing the mechanical strength of the vibrating
section 66. The stabilizer should preferably contain 1.5 to 6 mol % of yttrium oxide, or more preferably 2 to 4 mol % of yttrium oxide, and furthermore should preferably contain 0.1 to 5 mol % of aluminum oxide. - The crystalline phase may be a mixture of cubic and monoclinic systems, a mixture of tetragonal and monoclinic systems, or a mixture of cubic, tetragonal and monoclinic systems. Particularly, a mixture of cubic and monoclinic systems or a mixture of tetragonal and monoclinic systems as a major crystalline phase is most preferable from the standpoint of strength, tenacity, and durability.
- If the vibrating
section 66 is made of ceramics, then it is constructed of relatively many crystal grains. In order to increase the mechanical strength of the vibratingsection 66, the average diameter of the crystal grains should preferably be in the range from 0.05 μm to 2 μm and more preferably in the range from 0.1 μm to 1 μm. - The fixed
section 68 should preferably be made of ceramics. The fixedsection 68 may be made of ceramics which is the same as or different from the ceramics of the vibratingsection 66. As with the material of the vibratingsection 66, the ceramics of the fixedsection 68 may be stabilized zirconium oxide, aluminum oxide, magnesium oxide, titanium oxide, spinel, mullite, aluminum nitride, silicon nitride, glass, or a mixture thereof. - The
actuator substrate 32 used in thedisplay device 30A according to the first specific example is made of a material containing zirconium oxide as a chief component, a material containing aluminum oxide as a chief component, or a material containing a mixture of zirconium oxide and aluminum oxide as a chief component. Particularly preferable is a material chiefly containing zirconium oxide. - Clay or the like may be added as a sintering additive. Components of such a sintering additive need to be adjusted so that the sintering additive does not contain excessive amounts of materials which can easily be vitrified, e.g., silicon oxide, boron oxide, etc. This is because while these easily vitrifiable materials are advantageous in joining the
actuator substrate 32 to the piezoelectric/electrostrictive layer 72, they promote a reaction between theactuator substrate 32 and the piezoelectric/electrostrictive layer 72, making it difficult to keep the desired composition of the piezoelectric/electrostrictive layer 72 and resulting in a reduction in the device characteristics. - Specifically, silicon oxide, etc. in the
actuator substrate 32 should preferably be limited to 3% by weight or less or more preferably to 1% by weight or less. The chief component referred to above is a component which occurs at 50% by weight or more. - The
optical waveguide plate 38 has such a refractive index that the light 33 introduced therein is totally reflected within theoptical waveguide plate 38 without passing through front and back surfaces thereof. Theoptical waveguide plate 38 is required to have a uniform and high transmittance in the wavelength range of the introducedlight 33. Theoptical waveguide plate 38 is not limited to any materials insofar as they have the above characteristics. Specific materials thereof include glass, quartz, light-transmissive plastics such as acrylic resin or the like, light-transmissive ceramics, or a plural-layer structural body of materials having different refractive indexes, or a material having a coating layer on its surface. - Operation and advantages of the
display device 30A according to the first specific example will be described with respect to comparison between an inventive example and a comparative example with reference toFIGS. 39A through 42 . - The inventive example has the same structure as the
display device 30A according to the first specific example, and the comparative example has the same structure as aconventional display device 300 shown inFIG. 52 . - First, the difference between aperture ratios per pixel will be described below. According to the comparative example, in terms of one
cell 50, as shown inFIG. 39B , the aperture ratio is determined by a contact area of sixpicture element assemblies 310, for example, formed onrespective actuators 306 on anactuator substrate 308 shown inFIG. 52 . Since the area of each of thepicture element assemblies 310 is limited by the area of thecorresponding actuator 306 and there is a gap between adjacentpicture element assemblies 310, the end faces of thepicture element assemblies 310 serve as an emission region 90 (shown shaded inFIG. 39B ), and the gap between thepicture element assemblies 310 serves as anon-emission region 92. Therefore, theemission region 90 is defined by six dot-shaped regions surrounded by thenon-emission region 92. - According to the inventive example, in terms of one
cell 50, as shown inFIG. 39A , the aperture ratio is determined by a contact area of onepicture element assembly 52 formed on thejoint plate 40 shown inFIG. 35 . In this case, the end face of thepicture element assembly 52 serves as anemission region 90, and the other portion serves as anon-emission region 92. Theemission region 90 can freely be established irrespective of the areas of theactuator 34 on theactuator substrate 32 and thedisplacement transmitter 76, and can include thenon-emission region 92 in the comparative example. Theemission region 90 can be widened to a range close to thecell 50. - According to the inventive example, the aperture ratio can be made much greater than the aperture ratio according to the comparative example.
- The difference between the amounts of displacement of actuators per pixel will be described below. According to the comparative example, as shown in
FIG. 40 , the voltage applied to theactuator 306 is controlled to change the amount of displacement of thepicture element assembly 310 to provide a state (emitted state) in which thepicture element assembly 310 contacts anoptical waveguide plate 304 and a state (extinguished state) in which thepicture element assembly 310 is spaced from theoptical waveguide plate 304. - According to the comparative example, because the
picture element assembly 310 directly formed on theactuator 306 is brought into and out of contact with theoptical waveguide plate 304, the shape of a vibratingsection 314 of theactuator 306 is reflected to a certain extent on the upper surface of thepicture element assembly 310. Therefore, when thepicture element assembly 310 is spaced from theoptical waveguide plate 304, the upper surface of thepicture element assembly 310 is made concave toward theoptical waveguide plate 304, i.e., forms aconcavity 316. Therefore, when a voltage is applied to theactuator 306 to displace thepicture element assembly 310 away from theoptical waveguide plate 304, if the amount of displacement is not sufficient, then the upper end of thepicture element assembly 310 remains in contact with theoptical waveguide plate 304, failing to achieve a fully extinguished state. - Specifically, when the
picture element assembly 310 is displaced away from theoptical waveguide plate 304, the central area of the end face of thepicture element assembly 310 is largely displaced as it corresponds to a region of theactuator 306 where the maximum amount of displacement is obtained. However, the displacement of the peripheral edge area of thepicture element assembly 310 is small as it corresponds to a region of theactuator 306 where the amount of displacement is small. For example, if a voltage applied to achieve a certain amount of displacement at the central area of thepicture element assembly 310 is represented by V1 and a voltage applied to achieve the same amount of displacement at the peripheral edge area of thepicture element assembly 310 by V2, then V2>V1. The difference between the amounts of displacement at the above areas manifests itself if the area of the end face of thepicture element assembly 310 is increased for the purpose of increasing the aperture ratio of the pixel. - If the distance between the
optical waveguide plate 304 and the upper end of thepicture element assembly 310 has to be equal to or greater than a distance d in order to space thepicture element assembly 310 fully from theoptical waveguide plate 304, then the amount of displacement of the peripheral edge area of thepicture element assembly 310 needs to be equal to or greater than the distance d. Therefore, the voltage to be applied to theactuator 306 has to be determined in view of the region of theactuator 306 which corresponds to the peripheral edge area of thepicture element assembly 310. - When the distance between the upper end of the
picture element assembly 310 and theoptical waveguide plate 304 is equal to or greater than d, the amount of displacement of the central area of the end face of thepicture element assembly 310 reaches a distance D which is greater than the distance d. For bringing thepicture element assembly 310 into contact with theoptical waveguide plate 304, it takes time until the bottom of theconcavity 316 contacts theoptical waveguide plate 304, posing a limitation on efforts to increase the response. - According to the inventive example, as shown in
FIG. 41 , the voltage applied to theactuator 34 is controlled, and the displacement thereof is transmitted to thedisplacement transmitter 76 and thejoint plate 40 to change the amount of displacement of thepicture element assembly 52 to provide a state (emitted state) in which thepicture element assembly 52 contacts theoptical waveguide plate 38 and a state (extinguished state) in which thepicture element assembly 52 is spaced from theoptical waveguide plate 38. - In this case, the
picture element assembly 52 formed on thejoint plate 40 has a flat end face regardless of the shape of the vibratingsection 66 of theactuator 34. Moreover, since the aperture ratio of the pixel is determined by thepicture element assembly 52 formed on thejoint plate 40 irrespective of the cross-sectional area of thedisplacement transmitter 76 formed on theactuator 34, thedisplacement transmitter 76 can be of a narrow configuration. Thus, thedisplacement transmitter 76 can be installed in a central region of theactuator 34 where the maximum amount of displacement is obtained, and the amount of displacement of thedisplacement transmitter 76 can be set to a value close to the maximum amount of displacement of theactuator 34. - If the distance between the
optical waveguide plate 38 and the upper end of thepicture element assembly 52 is equal to or greater than the distance d in order to space thepicture element assembly 52 fully from theoptical waveguide plate 38, then the voltage to be applied to theactuator 34 may be determined in view of the displacement of the region of theactuator 34 where the maximum amount of displacement is obtained. The voltage can thus be much lower than the voltage in the comparative example. As a result, the power consumption can be reduced, the voltage and cost of the driver circuit can be lowered, and the reliability can be increased. - Changes in brightness due to defective actuators will be described below with reference to
FIGS. 39A through 42 . - According to the comparative example, in terms of one
cell 50, as shown inFIG. 39B , one pixel is made up of sixpicture element assemblies 210, for example, formed on therespective actuators 306 on the actuator substrate 308 (seeFIG. 32 ). - According to the inventive example, in terms of one
cell 50, as shown inFIG. 39A , one pixel is made up of onepicture element assembly 52 formed on the joint plate 40 (seeFIG. 41 ). Sixactuators 34 are present below thejoint plate 40. -
Numbers FIGS. 39A and 39B represent defective actuators as they increase in the sequence of the numbers. -
FIG. 42 shows a luminance change when the pixel is turned on and off with respect to the defect ratio (the number of defective actuators/the number of actuators that make up one pixel) of theactuators - According to the comparative example, as the number of defective actuators increase in the sequence shown in
FIG. 39 , the luminance change of the comparative example falls in proportion to the increase in the number of defective actuators as indicated by the solid-line curve A inFIG. 42 . - According to the inventive example, as indicated by the broken-line curve B in
FIG. 42 , the luminance change does not substantially fall if the defect ratio of theactuators 34 is equal to or smaller than 2/6, and the luminance change falls by about 5% if the defect ratio is 3/6. According to the inventive example, therefore, it is possible to keep the luminance change at a larger level in the presence of defective actuators than according to the comparative example. - If one pixel is made up of four
actuators 34 in an arrangement similar to the inventive example, then the luminance change does not fall at a defect ratio of ¼ or less. If one pixel is made up of threeactuators 34, then the luminance change does not fall at a defect ratio of ⅓ or less. - If one pixel is made up of two actuators in an arrangement similar to the comparative example, then the luminance change falls by 50% at a defect ratio of ½ or less. If one pixel is made up of two actuators in an arrangement similar to the inventive example, then the reduction of the luminance change is kept within 25% at a defect ratio of ½ or less.
- As described above, even if some
actuators 34 are defective, the percentage of defective products is reduced, but the percentage of good-quality products is increased, resulting in an increased yield and a reduction in the product cost. - When forces act to displace the
joint plate 40 downwardly due to the displacement of anormal actuator 34, the vibratingsection 66 of adefective actuator 34 flexes downwardly. Therefore, even in the presence of such adefective actuator 34, thejoint plate 40 is displaced according to the displacement of the normal actuator 34 (the region corresponding to thedefective actuator 34 is also displaced), causing thepicture element assembly 52 to operate normally. - With the
display device 30A according to the first specific example as described above, the singlejoint plate 40 is disposed between theoptical waveguide plate 38 and theactuator substrate 32, and thespacers 44 are disposed between theactuator substrate 32 and thejoint plate 40 and between theoptical waveguide plate 38 and thejoint plate 40 in alignment with therespective cells 50. Consequently, in regions of thejoint plate 40 close to thespacers joint plate 40 itself tends to be reduced due to the tension of the joint plate 40 (its rigidity is increased). However, as shown inFIG. 43 , ifslits 110 are formed in portions of thejoints 190 between thecells 50 on thejoint plate 40 closely to thespacers 42, then the rigidity of the above portions (part of the joints 190) is lowered to avoid the above displacement and lessen thermal stresses and mechanical stresses. - With the
slits 110 formed in thejoint plate 40, there are formed portions of thejoint plate 40 that are narrowed by theslits 110, i.e., portions (hereinafter simply referred to as arms 111) interconnecting the boundary regions (fixed regions) of thecells 50 and regions (movable regions) corresponding to thepicture element assemblies 52. - In order to keep the displacement of the regions of the
joint plate 40 which correspond to thepicture element assemblies 52 and allow thejoint plate 40 to be handled in the fabrication process, it is of course suitable to give thearms 111 appropriate rigidity, and it is preferable to optimize the shape, thickness, and structure of thearms 111. More preferably, the movable regions should be of increased flexural rigidity to compensate for the displacement of defective actuators, and thearms 111 should be of reduced flexural rigidity. - The
slits 110 can be formed in thejoint plate 40 and the thickness of thearms 111 can be made larger than the surrounding regions by a half-etching process, a sand blasting process, or the like. The fixed regions may be clamped and the movable regions may then be lowered in the direction of the thickness thereof to elongate the arms 11, and thereafter the movable regions may be raised in the opposite direction to turn the side elevational shape of thearms 111 into an arch shape, which is effective to reduce the reduction in the displacement under the tension of thearms 111. The planar shape of thearms 111 may be an L shape, a swirling shape, a bellows shape, or the like, as well as the straight shape shown inFIG. 43 , thus increasing the length of thearms 111. - A
display device 30B according to a second specific example will be described below with reference toFIG. 44 . Those parts of thedisplay device 30B which correspond to those of the display device shown inFIG. 35 are denoted by identical reference characters, and will not be described in detail below. - As shown in
FIG. 44 , thedisplay device 30B according to the second specific example is of substantially the same structure of thedisplay device 30A according to the first specific example, but differs therefrom in that thejoint plate 40 is divided into segments corresponding to thecells 50. That is, a plurality ofjoint plates 40 are arranged in a plane between theoptical waveguide plate 38 and theactuator substrate 32. - Therefore, a plurality of
spacers 112 are formed between theoptical waveguide plate 38 and theactuator substrate 32, and are interposed between theoptical waveguide plate 38 and theactuator substrate 32 through gaps between adjacentjoint plates 40. - In the
display device 30B according to the second specific example, as thejoint plate 40 is divided into segments corresponding to thecells 50, thejoint plates 40 are free of interference with the tension of adjacentjoint plates 40 and thespacers 112 when they are displaced. - If there is a defective actuator, then the
joint plate 40 is somewhat affected by a reduction in the displacement due to the defective actuator. If sixactuators 34, for example, are assigned to onepicture element assembly 52, then a luminance change is 0% when the defect ratio ofactuators 34 is ⅙, about 3% when the defect ratio ofactuators 34 is 2/6, and about 5% when the defect ratio ofactuators 34 is 3/6. Therefore, thedisplay device 30B according to the second specific example has substantially the same performance as thedisplay device 30A according to the first specific example. - Examples in which the
actuator device 10D according to the fourth embodiment is applied to other uses than the display device will be described below with reference toFIGS. 45 through 38 C. - A
variable capacitor 120 according to a specific example shown inFIG. 45 has adrive section 36 including a plurality ofactuators 34 arranged in a plane on anactuator substrate 32, a fixedelectrode 122 comprising a single metal plate disposed facing thedrive section 36, and amovable electrode 124 comprising a single metal plate which is disposed between theactuator substrate 32 and the fixedelectrode 122 and to which drive forces from theactuators 34 of thedrive section 36 are transmitted throughdisplacement transmitters 76. The fixedelectrodes 122 are fixed to theactuator substrate 32 byspacers 112 that are interposed between the fixedelectrode 122 and theactuator substrate 32. - With the
variable capacitor 120, themovable electrode 124 is moved toward and away from the fixedelectrode 122 when theactuators 34 are operated. That is, a distance da between themovable electrode 124 and the fixedelectrode 122 is changed accurately by theactuators 34, changing the electrostatic capacitance between theelectrodes - The dynamic range of the electrostatic capacitance can be increased by increasing the confronting areas of the fixed
electrode 122 and themovable electrode 124. Since a plurality ofactuators 34 are assigned to a singlemovable electrode 124, the distance between the fixedelectrode 122 and themovable electrode 124 can accurately be controlled. - Even if there is a defective actuator, the characteristics of the
variable capacitor 120, i.e., the changing characteristics of the electrostatic capacitance with respect to the level of a control signal supplied to thevariable capacitor 120, remain almost unchanged. Therefore, the yield ofvariable capacitors 120 of stable characteristics is increased. - In the above example, each of the fixed
electrode 122 and themovable electrode 124 comprises a metal plate.FIG. 46 shows avariable capacitor 120 a according to a modification in which a fixedelectrode 122 comprises aplate member 125 made of a desired material such as glass, ceramics, resin film, or the like and an electricallyconductive film 126 formed on theplate member 125, and amovable electrode 124 comprises aplate member 127 made of a desired material such as glass, ceramics, resin film, or the like and an electricallyconductive film 128 formed on theplate member 127. - An interference
optical modulator 130 according to a specific example shown inFIG. 47 has adrive section 36 including a plurality ofactuators 34 arranged in a plane on anactuator substrate 32, a singletransparent plate 132 facing thedrive section 36, and asingle mirror member 134 which is disposed between theactuator substrate 32 and thetransparent plate 132 and to which drive forces from theactuators 34 of thedrive section 36 are transmitted throughdisplacement transmitters 76. Thetransparent plate 132 is fixed to theactuator substrate 32 byspacers 112 that are interposed between thetransparent plate 132 and theactuator substrate 32. - With the interference
optical modulator 130, when input light Li is applied through thetransparent plate 132 to themirror member 134, light (first reflected light L1) reflected by the boundary between the reverse side of the transparent plate 132 (which faces the mirror member 134) and light (second reflected light L2) reflected by the surface of themirror member 134 are emitted as output light Lo. The first reflected light L1 and the second reflected light L2 interfere with each other, and the spectral distribution of the output light Lo is determined by the distance db between thetransparent plate 132 and themirror member 134. Therefore, when theactuators 34 operate to bring themirror member 134 toward and away from thetransparent plate 132, the distance db between thetransparent plate 132 and themirror member 134 is changed to control the spectral distribution of the output light Lo as desired. The interferenceoptical modulator 130 can be used as a color display device, a color filter, a light switch, or the like. Particularly, inasmuch as a joint plate is used in the interference section (the mirror member 134), the surface to which light is applied may be made flat, and the interference section may be provided in a wide area. Even if some of the actuators are defective, they have substantially no effect on the displacement of the interference section. In the above example, the upper surface of the interference section is flat. However, the upper surface of the interference section may be slanted or may have surface irregularities as required. - As shown in
FIG. 48A , amirror member 134 may comprise ametal plate 135 having amirror surface 135 a which faces the transparent plate 132 (seeFIG. 47 ). As shown inFIG. 48B , amirror member 134 may comprise aplate member 136 and alight reflecting film 137 directly formed on a portion of the surface of theplate member 136 which faces thetransparent plate 132. Alternatively, as shown inFIG. 48C , amirror member 134 may comprise aplate member 136, and alight reflecting film 137 formed on a portion of the surface of theplate member 136 which faces thetransparent plate 132, with abase layer 138 interposed between theplate member 136 and thelight reflecting film 137. In the examples shown inFIGS. 48B and 48C , the surface of theplate member 136 should preferably be a light absorbing surface to prevent unwanted scattered light from being produced. - Each of the
actuator devices 10A through 10D according to the first through fourth embodiments employs thesubstrate 12. However, a structure free of thesubstrate 12 may also be employed. - An
actuator device 10E according to a fifth embodiment which is free of thesubstrate 12 will be described below with reference toFIG. 49 . - As shown in
FIG. 49 , theactuator device 10E according to the fifth embodiment employs alaminated assembly 156 of a vibratingplate layer 152 and apiezoelectric function layer 154, instead of thesubstrate 12. - The
piezoelectric function layer 154 has a plurality oflower electrodes 74 a formed on the vibratingplate layer 152, a piezoelectric/electrostrictive layer 72 formed on the entire surface of the vibratingplate layer 152 including thelower electrodes 74 a, and a plurality ofupper electrodes 74 b formed on the piezoelectric/electrostrictive layer 72. The vibratingplate layer 152 amplifies the displacement amount of the piezoelectric/electrostrictive layer 72. Thelaminated assembly 156 has a structure including an array ofactuators 14, and serves as adrive section 16. The vibratingplate layer 152 may be made of the same material as or may be made of a different material from the piezoelectric/electrostrictive layer 72 of thepiezoelectric function layer 154. Thelaminated assembly 156 may be produced by laminating ceramic green sheets, and theupper electrodes 74 b and thelower electrodes 74 a may easily be formed by a screen printing process or the like. - The
actuator device 10E according to the fifth embodiment has thedrive section 16, a singlefirst plate member 18 to which drive forces from theactuators 14 of thedrive section 16 are transmitted, and a singlesecond plate member 20 confronting thefirst plate member 18. - A plurality of
spacers 22 are disposed between thefirst plate member 18 and thesecond plate member 20, forming mcells 15, for example. A plurality ofspacers 24 are also disposed between thefirst plate member 18 and thelaminated assembly 156 forming them cells 15. N actuators 14 are assigned to each of thecells 15.Displacement transmitters 76 for transmitting drive forces from theactuators 14 to thefirst plate member 18 are formed on therespective actuators 14. - The
upper electrodes 74 b of thelaminated assembly 156 have electrode patterns divided in therespective cells 15 or electrode patterns divided in respective rows, and thelower electrodes 74 a have electrode patterns divided in therespective actuators 14. Theelectrodes 74 a, 74 d may be vertically switched around. - The
laminated assembly 156 is disposed on afixed plate 158 by a plurality ofspacers spacers plate 158 include, for example, a plurality offirst spacers 160 positionally aligned with thespacers 24 disposed between thefirst plate member 18 and thelaminated assembly 156, and a plurality ofsecond spacers 162 disposed in thecells 15 in regions except for theactuators 14. - With the
actuator device 10E according to the fifth embodiment, since portions (which are not positionally aligned with the actuators 14) of the vibratingplate layer 152 are fixed by the first andsecond spacers plate 158, spaces surrounded by the fixedplate 158, the first andsecond spacers plate layer 152 have the same functions as thecavities 64 in theactuator substrate 32 shown inFIG. 35 , making it easy to determine the direction in which theactuators 14 are displaced. - As the
laminated assembly 156 is supported on the fixedplate 158 by the first andsecond spacers actuators 14 and thecells 15 can be reduced. In addition, the response of switching (the displacement of the first plate member 18) is also increased. The fixedplate 158 is effective to increase the mechanical strength of theactuator device 10E itself, which can easily be handled while being delivered or manufactured. - A plurality of piezoelectric function layers 154 may be laminated to increase the amount of displacement and generated forces of the
actuators 14. Any arbitrary displacement modes can be achieved by changing the installed positions of thespacers upper electrodes 74 b and thelower electrodes 74 a. - If the
actuator device 10E according to the fifth embodiment is to be applied to a display device, then thesecond plate member 20 is used as theoptical waveguide plate 38, light shield layers 70 (indicated by the two-dot-and-dash lines) are disposed between thesecond plate member 20 and thespacers 22, and picture element assemblies 52 (indicated by the two-dot-and-dash lines) are disposed on thefirst plate member 18. -
FIG. 50 shows an actuator device 10Ea according to a first modification of theactuator device 10E according to the fifth embodiment. The actuator device 10Ea according to the first modification is free of thesecond plate member 20.FIG. 51 shows an actuator device 10Eb according to a second modification which is free of thesecond plate member 20 and the fixedplate 158. Even in the absence of the fixedplate 158, since thelower electrodes 74 a have electrode patterns divided in therespective actuators 14, those regions which are free of thelower electrodes 74 a are not flexurally displaced and are joined to the regions where thespacers 24 are present. Therefore, theactuators 14 are flexurally displaced while the regions which are free of thelower electrodes 74 a are joined to the regions where thespacers 24 are present at the same height. - The actuator device (including the various modifications) according to the fifth embodiment which has the piezoelectric function layer can more flexibly and easily be changed in design than the structure having the
substrate 12 because the magnitude of the flexural displacement and the pattern of the displacement can be changed as desired by the electrode patterns of the upper and lower electrodes. The occurrence of defective actuators is also reduced. These advantages are produced because the piezoelectric function layer is uniformly formed of a ceramic green sheet. - The actuator device according to the present invention is not limited to the above embodiments, but may incorporate various structures without departing from the essential features of the present invention.
Claims (19)
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2003277887 | 2003-07-22 | ||
JP2003-277887 | 2003-07-22 | ||
JP2004-195070 | 2004-06-30 | ||
JP2004195070 | 2004-06-30 |
Publications (3)
Publication Number | Publication Date |
---|---|
US20050082946A1 US20050082946A1 (en) | 2005-04-21 |
US20060197413A9 true US20060197413A9 (en) | 2006-09-07 |
US7141915B2 US7141915B2 (en) | 2006-11-28 |
Family
ID=34525357
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/896,769 Expired - Fee Related US7141915B2 (en) | 2003-07-22 | 2004-07-22 | Actuator device |
Country Status (1)
Country | Link |
---|---|
US (1) | US7141915B2 (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20060118783A1 (en) * | 2004-12-02 | 2006-06-08 | Kim Sang H | Structure for optical device and method of fabricating the same |
US8659816B2 (en) | 2011-04-25 | 2014-02-25 | Qualcomm Mems Technologies, Inc. | Mechanical layer and methods of making the same |
US9190604B2 (en) | 2009-04-24 | 2015-11-17 | Ngk Insulators, Ltd. | Manufacturing method for thin board-shaped fired piezoelectric body |
US20160277843A1 (en) * | 2013-03-21 | 2016-09-22 | Noveto Systems Ltd. | Transducer system |
US20160376144A1 (en) * | 2014-07-07 | 2016-12-29 | W. L. Gore & Associates, Inc. | Apparatus and Method For Protecting a Micro-Electro-Mechanical System |
CN111601229A (en) * | 2019-02-20 | 2020-08-28 | Ask工业股份公司 | Method for manufacturing piezoelectric microphone with column structure |
Families Citing this family (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7313242B2 (en) * | 2004-03-16 | 2007-12-25 | Palo Alto Research Center Incorporated | Hypersonic transducer |
JP4484778B2 (en) * | 2005-07-08 | 2010-06-16 | 富士フイルム株式会社 | Small thin film movable element, small thin film movable element array, and driving method of small thin film movable element |
WO2008004664A1 (en) * | 2006-07-06 | 2008-01-10 | Nikon Corporation | Micro actuator, optical unit, exposure device, and device manufacturing method |
US8237334B2 (en) | 2009-04-22 | 2012-08-07 | Parker-Hannifin Corporation | Piezo actuator |
JP5828368B2 (en) * | 2010-12-14 | 2015-12-02 | セイコーエプソン株式会社 | Liquid ejecting head, liquid ejecting apparatus, piezoelectric element, and piezoelectric sensor |
JP5987510B2 (en) * | 2011-10-03 | 2016-09-07 | ミツミ電機株式会社 | Optical scanning device and optical scanning control device |
US9148716B2 (en) * | 2012-01-12 | 2015-09-29 | Aac Acoustic Technologies (Shenzhen) Co., Ltd. | Vibration speaker |
US9487445B2 (en) * | 2013-03-28 | 2016-11-08 | Tdk Corporation | Ceramic composition |
FR3010272B1 (en) * | 2013-09-04 | 2017-01-13 | Commissariat Energie Atomique | ACOUSTIC DIGITAL DEVICE WITH INCREASED AUDIO POWER |
US9510103B2 (en) * | 2013-09-09 | 2016-11-29 | Audio Pixels Ltd. | Microelectromechanical apparatus for generating a physical effect |
JP6372644B2 (en) * | 2014-01-20 | 2018-08-15 | セイコーエプソン株式会社 | Piezoelectric element, liquid jet head and sensor |
WO2017013665A1 (en) | 2015-07-22 | 2017-01-26 | Audio Pixels Ltd. | Dsr speaker elements and methods of manufacturing thereof |
US10567883B2 (en) | 2015-07-22 | 2020-02-18 | Audio Pixels Ltd. | Piezo-electric actuators |
US10404954B2 (en) * | 2016-01-21 | 2019-09-03 | Ricoh Company, Ltd. | Optical deflection apparatus, image projector, optical writing unit, and object recognition device |
DE102016111909B4 (en) * | 2016-06-29 | 2020-08-13 | Infineon Technologies Ag | Micromechanical structure and method of making it |
RU168462U1 (en) * | 2016-07-01 | 2017-02-03 | Федеральное государственное автономное образовательное учреждение высшего образования "Национальный исследовательский университет "Московский институт электронной техники" | HEAT MICROMECHANICAL ACTUATOR |
CN111405455B (en) * | 2019-01-02 | 2022-06-07 | 京东方科技集团股份有限公司 | Sound production device, manufacturing method thereof and display device |
Citations (33)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4742264A (en) * | 1985-03-08 | 1988-05-03 | Murata Manufacturing Co., Ltd. | Piezoelectric sound generator |
US5233256A (en) * | 1991-01-30 | 1993-08-03 | Murata Manufacturing Co., Ltd. | Method of driving piezoelectric bimorph device and piezoelectric bimorph device |
US5266964A (en) * | 1990-09-14 | 1993-11-30 | Brother Kogyo Kabushiki Kaisha | Piezoelectric ink jet printer head |
US5517076A (en) * | 1993-10-14 | 1996-05-14 | Ngk Insulators, Ltd. | Zirconia diaphragm structure and piezoelectric/electrostrictive element incorporating same |
US5545461A (en) * | 1994-02-14 | 1996-08-13 | Ngk Insulators, Ltd. | Ceramic diaphragm structure having convex diaphragm portion and method of producing the same |
US5594292A (en) * | 1993-11-26 | 1997-01-14 | Ngk Insulators, Ltd. | Piezoelectric device |
US5600197A (en) * | 1994-02-14 | 1997-02-04 | Ngk Insulators, Ltd. | Piezoelectric/electrostrictive film element and method of producing the same |
US5634999A (en) * | 1994-09-06 | 1997-06-03 | Ngk Insulators, Ltd. | Method of producing ceramic diaphragm structure having convex diaphragm portion |
US5709802A (en) * | 1991-06-11 | 1998-01-20 | International Business Machines Corporation | Method of making a micro-actuator device |
US5771321A (en) * | 1996-01-04 | 1998-06-23 | Massachusetts Institute Of Technology | Micromechanical optical switch and flat panel display |
US5852337A (en) * | 1996-05-27 | 1998-12-22 | Ngk Insulators, Ltd. | Piezoelectric film-type element |
US5862275A (en) * | 1996-07-10 | 1999-01-19 | Ngk Insulators, Ltd. | Display device |
US5867302A (en) * | 1997-08-07 | 1999-02-02 | Sandia Corporation | Bistable microelectromechanical actuator |
US5953469A (en) * | 1996-10-29 | 1999-09-14 | Xeotron Corporation | Optical device utilizing optical waveguides and mechanical light-switches |
US6028978A (en) * | 1996-12-16 | 2000-02-22 | Ngk Insulators, Ltd. | Display device having a colored layer disposed between a displacement transmitting section and an optical waveguide plate |
US6174051B1 (en) * | 1996-08-19 | 2001-01-16 | Brother Kogyo Kabushiki Kaisha | Ink jet head |
US6265811B1 (en) * | 1996-11-29 | 2001-07-24 | Ngk Insulators, Ltd. | Ceramic element, method for producing ceramic element, display device, relay device and capacitor |
US6291932B1 (en) * | 1998-02-17 | 2001-09-18 | Canon Kabushiki Kaisha | Stacked piezoelectric element and producing method therefor |
US20010041489A1 (en) * | 2000-03-10 | 2001-11-15 | Ngk Insulators, Ltd. | Method for producing display apparatus |
US6347441B1 (en) * | 1999-07-07 | 2002-02-19 | Samsung Electro-Mechanics Co., Ltd. | Manufacturing method of multilayered piezoelectric/electrostrictive ceramic actuator |
US6381381B1 (en) * | 1998-01-20 | 2002-04-30 | Seiko Epson Corporation | Optical switching device and image display device |
US6452583B1 (en) * | 1997-07-18 | 2002-09-17 | Ngk Insulators, Ltd. | Display-driving device and display-driving method |
US20020140348A1 (en) * | 2001-03-27 | 2002-10-03 | Ngk Insulators, Ltd. | Display apparatus |
US20020146330A1 (en) * | 2001-04-06 | 2002-10-10 | Ngk Insulators, Ltd. | Micropump |
US6470115B1 (en) * | 1997-06-18 | 2002-10-22 | Seiko Epson Corporation | Optical switching element and image display device |
US20030020370A1 (en) * | 2001-04-06 | 2003-01-30 | Ngk Insulators, Ltd. | Cell driving type actuator and method for manufacturing the same |
US20030063368A1 (en) * | 2001-09-03 | 2003-04-03 | Ngk Insulators, Ltd. | Display device and method for producing the same |
US6565331B1 (en) * | 1999-03-03 | 2003-05-20 | Ngk Insulators, Ltd. | Pump |
US6578245B1 (en) * | 1998-08-31 | 2003-06-17 | Eastman Kodak Company | Method of making a print head |
US6672714B2 (en) * | 1998-02-18 | 2004-01-06 | Sony Corporation | Ink-jet printhead |
US6690344B1 (en) * | 1999-05-14 | 2004-02-10 | Ngk Insulators, Ltd. | Method and apparatus for driving device and display |
US6700305B2 (en) * | 1999-12-20 | 2004-03-02 | Minolta Co., Ltd. | Actuator using a piezoelectric element |
US6919667B2 (en) * | 2001-09-13 | 2005-07-19 | Ngk Insulators, Ltd. | Piezoelectric/electrostrictive film device |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0965669A (en) | 1995-08-28 | 1997-03-07 | Sony Corp | Piezoelectric actuator |
JP3850130B2 (en) | 1998-03-13 | 2006-11-29 | キヤノン株式会社 | Multilayer piezoelectric element |
JPH11252333A (en) | 1998-02-27 | 1999-09-17 | Matsushita Electric Ind Co Ltd | Image reader |
JPH11339561A (en) | 1998-05-27 | 1999-12-10 | Ngk Insulators Ltd | Ceramic element, manufacture of ceramic element, display device, relay device and capacitor |
US6699018B2 (en) | 2001-04-06 | 2004-03-02 | Ngk Insulators, Ltd. | Cell driving type micropump member and method for manufacturing the same |
JP3942388B2 (en) | 2001-04-06 | 2007-07-11 | 日本碍子株式会社 | Micro pump |
JP2003052181A (en) | 2001-05-29 | 2003-02-21 | Olympus Optical Co Ltd | Piezoelectric actuator, driver of the same and camera having variable mirror using the piezoelectric actuator |
JP2003161896A (en) | 2001-09-03 | 2003-06-06 | Ngk Insulators Ltd | Display device and method for producing the same |
-
2004
- 2004-07-22 US US10/896,769 patent/US7141915B2/en not_active Expired - Fee Related
Patent Citations (35)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4742264A (en) * | 1985-03-08 | 1988-05-03 | Murata Manufacturing Co., Ltd. | Piezoelectric sound generator |
US5266964A (en) * | 1990-09-14 | 1993-11-30 | Brother Kogyo Kabushiki Kaisha | Piezoelectric ink jet printer head |
US5233256A (en) * | 1991-01-30 | 1993-08-03 | Murata Manufacturing Co., Ltd. | Method of driving piezoelectric bimorph device and piezoelectric bimorph device |
US5709802A (en) * | 1991-06-11 | 1998-01-20 | International Business Machines Corporation | Method of making a micro-actuator device |
US5733670A (en) * | 1993-10-14 | 1998-03-31 | Ngk Insulators, Ltd. | Zirconia diaphragm structure, method of producing the same, and piezoelectric/electrostrictive film element having the zirconia diaphragm structure |
US5517076A (en) * | 1993-10-14 | 1996-05-14 | Ngk Insulators, Ltd. | Zirconia diaphragm structure and piezoelectric/electrostrictive element incorporating same |
US5594292A (en) * | 1993-11-26 | 1997-01-14 | Ngk Insulators, Ltd. | Piezoelectric device |
US5600197A (en) * | 1994-02-14 | 1997-02-04 | Ngk Insulators, Ltd. | Piezoelectric/electrostrictive film element and method of producing the same |
US5545461A (en) * | 1994-02-14 | 1996-08-13 | Ngk Insulators, Ltd. | Ceramic diaphragm structure having convex diaphragm portion and method of producing the same |
US5634999A (en) * | 1994-09-06 | 1997-06-03 | Ngk Insulators, Ltd. | Method of producing ceramic diaphragm structure having convex diaphragm portion |
US5771321A (en) * | 1996-01-04 | 1998-06-23 | Massachusetts Institute Of Technology | Micromechanical optical switch and flat panel display |
US5852337A (en) * | 1996-05-27 | 1998-12-22 | Ngk Insulators, Ltd. | Piezoelectric film-type element |
US5862275A (en) * | 1996-07-10 | 1999-01-19 | Ngk Insulators, Ltd. | Display device |
US6174051B1 (en) * | 1996-08-19 | 2001-01-16 | Brother Kogyo Kabushiki Kaisha | Ink jet head |
US5953469A (en) * | 1996-10-29 | 1999-09-14 | Xeotron Corporation | Optical device utilizing optical waveguides and mechanical light-switches |
US6265811B1 (en) * | 1996-11-29 | 2001-07-24 | Ngk Insulators, Ltd. | Ceramic element, method for producing ceramic element, display device, relay device and capacitor |
US6476540B2 (en) * | 1996-11-29 | 2002-11-05 | Ngk Insulators, Ltd. | Ceramic element, method for producing ceramic element, display device, relay device, and capacitor |
US6028978A (en) * | 1996-12-16 | 2000-02-22 | Ngk Insulators, Ltd. | Display device having a colored layer disposed between a displacement transmitting section and an optical waveguide plate |
US6470115B1 (en) * | 1997-06-18 | 2002-10-22 | Seiko Epson Corporation | Optical switching element and image display device |
US6452583B1 (en) * | 1997-07-18 | 2002-09-17 | Ngk Insulators, Ltd. | Display-driving device and display-driving method |
US5867302A (en) * | 1997-08-07 | 1999-02-02 | Sandia Corporation | Bistable microelectromechanical actuator |
US6381381B1 (en) * | 1998-01-20 | 2002-04-30 | Seiko Epson Corporation | Optical switching device and image display device |
US6291932B1 (en) * | 1998-02-17 | 2001-09-18 | Canon Kabushiki Kaisha | Stacked piezoelectric element and producing method therefor |
US6672714B2 (en) * | 1998-02-18 | 2004-01-06 | Sony Corporation | Ink-jet printhead |
US6578245B1 (en) * | 1998-08-31 | 2003-06-17 | Eastman Kodak Company | Method of making a print head |
US6565331B1 (en) * | 1999-03-03 | 2003-05-20 | Ngk Insulators, Ltd. | Pump |
US6690344B1 (en) * | 1999-05-14 | 2004-02-10 | Ngk Insulators, Ltd. | Method and apparatus for driving device and display |
US6347441B1 (en) * | 1999-07-07 | 2002-02-19 | Samsung Electro-Mechanics Co., Ltd. | Manufacturing method of multilayered piezoelectric/electrostrictive ceramic actuator |
US6700305B2 (en) * | 1999-12-20 | 2004-03-02 | Minolta Co., Ltd. | Actuator using a piezoelectric element |
US20010041489A1 (en) * | 2000-03-10 | 2001-11-15 | Ngk Insulators, Ltd. | Method for producing display apparatus |
US20020140348A1 (en) * | 2001-03-27 | 2002-10-03 | Ngk Insulators, Ltd. | Display apparatus |
US20030020370A1 (en) * | 2001-04-06 | 2003-01-30 | Ngk Insulators, Ltd. | Cell driving type actuator and method for manufacturing the same |
US20020146330A1 (en) * | 2001-04-06 | 2002-10-10 | Ngk Insulators, Ltd. | Micropump |
US20030063368A1 (en) * | 2001-09-03 | 2003-04-03 | Ngk Insulators, Ltd. | Display device and method for producing the same |
US6919667B2 (en) * | 2001-09-13 | 2005-07-19 | Ngk Insulators, Ltd. | Piezoelectric/electrostrictive film device |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20060118783A1 (en) * | 2004-12-02 | 2006-06-08 | Kim Sang H | Structure for optical device and method of fabricating the same |
US7338825B2 (en) * | 2004-12-02 | 2008-03-04 | Electronics And Telecommunications Research Institute | Structure for optical device and method of fabricating the same |
US9190604B2 (en) | 2009-04-24 | 2015-11-17 | Ngk Insulators, Ltd. | Manufacturing method for thin board-shaped fired piezoelectric body |
US8659816B2 (en) | 2011-04-25 | 2014-02-25 | Qualcomm Mems Technologies, Inc. | Mechanical layer and methods of making the same |
US20160277843A1 (en) * | 2013-03-21 | 2016-09-22 | Noveto Systems Ltd. | Transducer system |
US9820055B2 (en) * | 2013-03-21 | 2017-11-14 | Noveto Systems Ltd. | Transducer system |
US20160376144A1 (en) * | 2014-07-07 | 2016-12-29 | W. L. Gore & Associates, Inc. | Apparatus and Method For Protecting a Micro-Electro-Mechanical System |
CN111601229A (en) * | 2019-02-20 | 2020-08-28 | Ask工业股份公司 | Method for manufacturing piezoelectric microphone with column structure |
Also Published As
Publication number | Publication date |
---|---|
US20050082946A1 (en) | 2005-04-21 |
US7141915B2 (en) | 2006-11-28 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7141915B2 (en) | Actuator device | |
EP0818700B1 (en) | Display device | |
US6091182A (en) | Piezoelectric/electrostrictive element | |
JP3187669B2 (en) | Display element and display device | |
US7110160B2 (en) | Electrical contacts in microelectromechanical devices with multiple substrates | |
EP1220190B1 (en) | Reflective display device | |
US6624549B2 (en) | Piezoelectric/electrostrictive device and method of fabricating the same | |
US6724973B1 (en) | Display and its manufacturing method | |
US7444052B2 (en) | Display device | |
JP4783558B2 (en) | Actuator device | |
EP1245988A2 (en) | Display apparatus | |
US6453100B1 (en) | Display device and method for producing the same | |
US6879753B2 (en) | Display device | |
US20030025442A1 (en) | Display device and method for producing the same | |
JP2005057250A (en) | Actuator apparatus and its manufacturing method | |
US20030026564A1 (en) | Display device and method for producing the same | |
CN115050280B (en) | Display module and display device | |
JPH11194723A (en) | Display device | |
KR970003444B1 (en) | Manufacturing method of actuated array | |
EP1199696A1 (en) | Display device and method of manufacture thereof | |
KR970003442B1 (en) | Optical path regulator for projector | |
KR970003010B1 (en) | Driving method of optical path regulating apparatus | |
JP2004045445A (en) | Display device | |
JP2001343598A (en) | Display device and method of manufacturing the same | |
KR19990043432A (en) | Improved thin film type optical path control device and manufacturing method thereof |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: NGK INSULATORS, LTD., JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:TAKEUCHI, YUKIHISA;NANATAKI, TSUTOMU;KIMURA, KOJI;AND OTHERS;REEL/FRAME:016044/0208 Effective date: 20041129 |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
FEPP | Fee payment procedure |
Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
FPAY | Fee payment |
Year of fee payment: 8 |
|
FEPP | Fee payment procedure |
Free format text: MAINTENANCE FEE REMINDER MAILED (ORIGINAL EVENT CODE: REM.) |
|
LAPS | Lapse for failure to pay maintenance fees |
Free format text: PATENT EXPIRED FOR FAILURE TO PAY MAINTENANCE FEES (ORIGINAL EVENT CODE: EXP.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
STCH | Information on status: patent discontinuation |
Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |
|
FP | Lapsed due to failure to pay maintenance fee |
Effective date: 20181128 |