CA1228407A - Position sensor - Google Patents
Position sensorInfo
- Publication number
- CA1228407A CA1228407A CA000451789A CA451789A CA1228407A CA 1228407 A CA1228407 A CA 1228407A CA 000451789 A CA000451789 A CA 000451789A CA 451789 A CA451789 A CA 451789A CA 1228407 A CA1228407 A CA 1228407A
- Authority
- CA
- Canada
- Prior art keywords
- light
- light conductors
- conductors
- layer
- position sensor
- 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.)
- Expired
Links
- 239000004020 conductor Substances 0.000 claims abstract description 121
- 230000003287 optical effect Effects 0.000 claims abstract description 9
- 239000012876 carrier material Substances 0.000 claims abstract description 5
- 230000001419 dependent effect Effects 0.000 claims description 4
- 238000009740 moulding (composite fabrication) Methods 0.000 claims 4
- 108010014172 Factor V Proteins 0.000 claims 3
- 230000000875 corresponding effect Effects 0.000 claims 2
- 230000008878 coupling Effects 0.000 abstract description 3
- 238000010168 coupling process Methods 0.000 abstract description 3
- 238000005859 coupling reaction Methods 0.000 abstract description 3
- 238000001514 detection method Methods 0.000 description 5
- 239000000969 carrier Substances 0.000 description 3
- 230000004913 activation Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 241001424413 Lucia Species 0.000 description 1
- 206010028980 Neoplasm Diseases 0.000 description 1
- 241000282320 Panthera leo Species 0.000 description 1
- 208000003251 Pruritus Diseases 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 229910002056 binary alloy Inorganic materials 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
- 239000013013 elastic material Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000005693 optoelectronics Effects 0.000 description 1
- 210000003254 palate Anatomy 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000012780 transparent material Substances 0.000 description 1
- 230000001755 vocal effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/24—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
- G01L1/242—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet the material being an optical fibre
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/24—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
- G01L1/247—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet using distributed sensing elements, e.g. microcapsules
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/042—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by opto-electronic means
- G06F3/0421—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by opto-electronic means by interrupting or reflecting a light beam, e.g. optical touch-screen
Abstract
ABSTRACT:
Position sensor.
The force-sensitive position sensor or writing tablet is composed (for each of the two coordinate directions) of two layers of parallel extending light conductors having a spacing of 0.1 mm or less, the distance between the two layers being approximately 5 µm. By locally exerting a force on the carrier material in which the light conductors ar embedded (for example), by means of the tip of a stylus), the light conductors are geometrically deformed. These deformations cause a variation of the optical coupling between the two locally deformed conductors, thus causing a detectable transfer of light (variation) from one conductor to the other. By connection of one layer to a light source and the other layer to a suitable detector, a force-sensitive position sensor can be constructed by means of electro-optical means.
Position sensor.
The force-sensitive position sensor or writing tablet is composed (for each of the two coordinate directions) of two layers of parallel extending light conductors having a spacing of 0.1 mm or less, the distance between the two layers being approximately 5 µm. By locally exerting a force on the carrier material in which the light conductors ar embedded (for example), by means of the tip of a stylus), the light conductors are geometrically deformed. These deformations cause a variation of the optical coupling between the two locally deformed conductors, thus causing a detectable transfer of light (variation) from one conductor to the other. By connection of one layer to a light source and the other layer to a suitable detector, a force-sensitive position sensor can be constructed by means of electro-optical means.
Description
PUN. Lowe 1 '15.3.
Position sensor.
The invention relates to a position sensor for worming, using optical means, an electric signal which is dependent of the position of an end of a pointing member weakly bears on the position sensor.
A position sensor of this kind is known from a publication by S. Tumor et at in Applied Optics, Vol. 19, No. 11, June 1, 19~0, The described sensor is formed by a rectangular flat plate which is surrounded by oppositely situated rows of light emitting and detecting diodes.
10 An end of a pointing member, for example, a stylus positioned on the flat plate interrupts the light which is emitted by the rows of diodes in a given sequence and which is detected more or less by the oppositely situated diodes. Each photo diode should be connected -to a so-called 15 coherent detection circuit; consequently, a sizable position sensor offering a suitable resolution is an ox-pensive device. Furthermore, the resolution and the absolute size of -the position sensor are restricted by -the low directional sensitivity of the photo diodes and also by the 20 minimum signal-to-noise ratio required.
I-t is an object of -the invention to provide a position sensor which allows for a comparatively high resolution in a large surface area to be chosen. It is a further object of the invention to provide a position sensor 25 whose electronic circuits are very simple and limited in Sue.
To this end, a position sensor in accordance with the invention is caricatured in -that it comprises at least two layers of light conductors which are embedded in a 30 light conducting carrier material whose refractive index is lower than the refractive index of -the light conductors, the light conductors in both layers extending parallel -to one another, the spacing of -the light conductors in each '7 Ply 4 2 15.3.811 layer being larger than the dustiness between -two light con-cluctors which are substantially oppositely situated in the two layers, the light conductors in a firs-t layer being connected -to a light source whilst the light conductors in the second layer are connected to a light detector. In -the force sensitive position sensor a position of a tip of a writing tool is determined by the occurrence of light trays-for between two light conductors. It follows -therefrom -that a very high resolution can be achieved by using very thin 10 light conductors (diameter in the order of magnitude of a few sum), and -that the position of the -tip of -the writing -tool is determined by detection of the light transfer between -two of such light conductors.
The invention will be described in detail herein-15 after with reference to a number of embodiments which are shown in the drawing therein Figure 1 shows -the principle used in the position sensor in accordance with the invention, Figures pa and b diagrammatically show -the 20 construction of -the position sensor in accordance with the invention, Figure 3 diagrammatically shows an opto-mechanical position decoding device for a writing -tablet in accordance with the invention, Figure shows an optomechanical position encoding device, and Figures pa and b show an optoelectronic position decoding circuit for a position sensor in accordance with the invention, as well as a de-tail thereof.
Figure 1 shows -two glass or plastics light conductors 1 and 2 which extend in -the y-direction of a Cartesian system of coordinates x-y-z. The light conductors 1 and 2 are embedded in a carrier 3 of a transparent material end are situated one over the other a-t a distance of 35 approximately from 5 -to 10/um, viewed in -the z-clirec-tion.
The conductors 1 and 2 themselves have a diameter of from 3 -to 5 sum. All dimensions are given by way of example and are, of course, depellden-t on the wavelength of the light '7 PIN . l o, Go I 3 1 5 . 3 I
used. The retractive inc1ex of the -Iigll-t conc1uc-tors 1 end 2 is slightly haggler 1 c/O) than that of -the material of -the carrier 3 surroi~nc1ing -the light conductors I and 2. Light 5 is radiatec1 -in-to -the ligate conductor 1 by a diode 4. In normal circumstances -the light 5 will -travel -through the slight conductor 1 in order to emerge therefrom a-t the end 1' thereof. When a force F is exerted on the carrier 3 so that acutely a local geometrical deformation occurs, -the optical coupling between -the light conductors 1 anal 2 Jill change 10 anc1-the part of -the light which propagates outside -the conductor 1 Jill also change; part thereof will then pro-palate in -the conductor 2. The light 5' which emerges from an end 2' of the light conductor 2 will be detected by a photosensitive diode 6. The degree of optical coupling be-15 tweet the light conductors 1 and 2 depends in a complex manner on the light conductor configuration, dimensions, such as spacing, refractive index, refractive index profile, wavelength of -the light used, etch A model of -the phenomenon "perturbation of wave propagation and its dependence on I said parameters has already been described in Phillips Journal of research, Vol. 33, No. 5/6, 197~, pages 254-263, by D. Tjaden.
When, vocal in the direction pairs of light conductors are adjacently arranged in such a carrier 3 25 arranged over one another in the direction and extending in -the y-direction) a-t a distance I 100/um) which is large with respect -to the distance in -the z-direction I 5-10/-um) an x-position sensor is obtained which (viewed in the direction produces 7 at the area where a 30 force F is exerted on -the carrier 3, a light signal on an "outgoing" light conductor 2 when light is radiated into the associatecL light conductor 1. The carrier 3 firs-t of all serves -to maintain the light conductors 1 end 2 a-t the correct distance from one another so -that light can be 35 -transferred there between, and also serves for mechanical protection of -the light conductors.
Figure pa diagrammatically shows the construction of a position sensor. In a firs-t layer I a row of light PllN.lo.Gll4 Lo. 1 5 . '3. I
condl1ctors Rockwell extend in the y-clirection is arranged in the x-direction. In a layer II there is arranged a second row of legality conductors which extend parallel -to the light conductors in the furriest layer I. Each light conductor in tile slayer I is situated exactly over (viewed in the z-direction) a light conductor in the layer II as appears also from Figure 1. The layers III and IV in Figure pa are identical to the layers I and II with -the exception of` the direction (x-direction). The light conductors in -the layers 10 III and IV are directed a-t right angles to the light con-doctors in -the layers I and II. If necessary, the spacing of the light conductors in the layers III and IV differs from that in the layers I and II. The ends of -the light-conductors 2x of -the layer II are bundled and fed to a 15 photodiocle 6x. Similarly, the ends of the light conductors my of -the layer IV are bundled and fed to a photo diode my.
The ends of` the ligtlt conductors 1x and lye of -the layers I and III, respectively however, are adjacently arranged in a row in the correct sequence. When a force F is exerted on the stack of the four layers I -to IV in a point p, the diodes 6x and/or my detect, when the light conductors 1x and my are alternately irradiated, a light signal emerging from the light conductors 2x and my if -those light conductors 1x and/or my are irradiated which extend exactly underneath -the point p or Lucia are situated sufficiently near this point. I-t will be apparent that such a position sensor allows for a high resolution (Jo 10 linesmen and that i-t is very suitable as a writing or drawing table-t, because the light conductors allow for such a spacing and the -tip of customary writing -tools (for example, a ballpoint) exerts a force on a surface which has a diameter in -the same order of magnitude.
Figure 2b is a diagrammatic sectional view (not to scale) of the layer-wise composition of the position sensor or the writing tablet shown in Figure aye.
The -thickness of the carriers 3x and my in which the layers I and II, III and IV, respectively, are situated alnounts P~1~.1.). Glue 5 1 5. 3. Jo to 100/l1m. Each of the carriers 3x and my comprises -three layers: a first layer 31 and a thirc1 layer 33, each having a thicklless of illume, and a second layer 32 which has a thickness of sum and which is enclosed by -the first and the third layer. The conductors 1x in -the layer 31 and the conductors 2x in the layer 33 are arranged at -the sides of the layers 31 and 33 which adjoin the second layer 32.
Siniilarly, -the conductors lye and my are arranged on both sides of the enclosed layer 32 of -the carriers my. It is 10 alternatively possible to form conductors in the second layer 32. Use is -then made of a second layer (for example, having a thickness of 15/um) in which light conductive tracks are formed on both sides by means of known techniques (for example, see the book "Planar Optical Wave Guides and 15 Fires", Chapter 3, 1977, bug. Urger, published by Clarendon Press, oxford). Because -the position sensor or the writing -tablet has a thickness of only a few tenths of a millimeter and because i-t is transparent, the sensor or -the writing tablet, when made of an elastic material, 20 can be arranged directly against a display screen of, for example a computer -terminal so that direct interaction with the computer is possible.
As has already been statical, the position of the force F exerted can be determined by irradiating the 25 light conductors I and my one by one and by detecting the light intercepted by one of each group of light conductors 2x and my When the Light conductors lo and lye are periodic-ally irradiated, -the instant at which light is detected a-t an exit of the light conductors 2x and my within such a 30 period will be decisive for -the position I.
Figure 3 diagrammatically shows an embodiment of a position detection mechanism of the described kind.
The light conductors lo are arranged in a row and are irradiated one by one by a light beam which is reflected to the ends of -the light conductors lo via a rotating prism S. In order to know -the position of the light beam (actually the position of -the irradiated light conductor), the prism S is mechanically coupled -to a pulse generator PG.
-134~
PUN G I 5. 3. I
The pulse generator PUG comprises a disc TO which rotates in synchronism w-itI-I-tlle mirror S end which generates pulses in cooperation with a photo diode and a light emitting diode FED, said pulses being applied to a counter I The position 5 of the counter I is a measure of -the position of the prism S and hence a measure of the position of the light conductor 1x being irradiated at the relevant instant. When a force is exerted on the position sensor or thwarting tablet 10 in a point p, a detection transistor D receives a light pulse via the bundled outgoing light conductors 2x if the light conductor 1x extends underneath the point I. The tray-sister D subsequently applies a control pulse -to a buffer circuit B , with the result -that -the position of the counter Ox is transferred to the buffer By. The buffer By contains -the counter position in which a transfer of light took place from one of the light conductors Ix to 2x, so that it in-dilates the position (in the x-clirection). Evidently, for the determination of the position use can be made of a similar opto-mechanical decoding device, Instead of a rotating prism S end the pulse generator Pause can alter-natively be made 0~7 for example a piezoelectric crystal on which a mirror is mounted in order to irradiate the row of light conductors 1x. The control. voltage for the pus-electric crystal is -then a measure of the position of the light beam Jo , and hence of the position of the irradiated light conductor 1x. Obviously, the en-tire irradiation and detection mechanism can be completely reversed, the bundled light conductors 2x then being irradiated and the light conductors 1x being sequentially sampled for the deter-munition of the position of -the pressure point p. To this end it is merely necessary to arrange the transistor D in the location of the light source L and vice versa; of course, the output of the transistor D remains connected to the 35 control input of the buffer By.
Figure Lo shows a further embodiment of a position duckling device for a position sensor 20 in accordance with the invention. The light eondLIctors 1x of the first layer PING 7 l5.3.Sl~
are bundled end ore irradiated by a light-emittlng diode ED.
Tire outgoing light conductors 2x old the position sensor 20 are arranged in a row which ex-terlcls transversely of a propagation direction V of a photosensitive tape 30 which -trowels at a speed 'I , the ends of -the light conductors 2x being directed perpendicularly to -the tape surface. The The light pulses emetically by the diode LO (emission frequency f) produce exposed (colored) spots on the tape 30 with a spacing I viewed in -the propagation direction V.
The position of an exposed spot on -the tape 30 (viewed transversely of -the direction V) depends on the position P
on the position sensor 20 in which a force is exerted.
For the sake of clarity, on the sensor 20 there is shown a curve 21 on -which -there are indicated points P which 15 produce an exposed spot P' on the -tape 30 when the curve 21 is drawn on the sensor 20 by means of a writing tool.
It is -to be noted -that, when the tip of the writing -tool is held stationary during drawing, light spots are continuously written in -the same position (viewed transversely of the 20 direction V); by way of example, in Figure -the writing -tool has been held stationary at tile beginning as well as at the end of -the curve 21 9 -thus producing the points P'' and P''', respectively, on the -tape 30. I-t will be apparent that yin Figure only -the coordinate is defined. The y-coordinate associated with each x-coorcdina-te can be deter-mined in a similar manner. I-t is useful -to arrange the no of ends of the light conductors my in the prolongation of the row of light conductors 2x, so -that -the x-coordinate as well as the associated y-coordinate can -thus be defined on -the -tape 30 on a line which extends -transversely of -the direction V. A -tape 30 thus formed can be used for data input for computer equipment in the same way as a convent -tonal punched -tape.
Figure 5 shows a preferred embodiment of a position sensor or writing tablet 100 in accordance with -the invention. Again only a one-dimensional position PUN. G 'I 'I S 1 5 . 3 . I
clutter anion is represented; a -two-climensionl:L position determinatioll can be performec1 by doubling -the components Shelley, the ac1cled group of components being connected -to groups of fight conductors which are directed -transversely 5 of the fight conductors Al 3 end Allah; B1_3 an 1-3 Of 3 end Of 3 shown in Figure I The writing -tablet 100 and the associated components do not comprise moving parts (as yin -the Figures 3 and 4) end produce digital electric output signals on outputs To Lo which are suitable or 10 direct input into a computer. The incoming end outgoing light conductors Al 3, By 3' C1 3 end Aye, B1_3 and C1_3~
respectively, are subdivided in-to groups in a special way so -that the number of Light emitting diodes LID 3 and the number ox detectors Do 3 can remain limited illicit a high 15 resolution can s-till be achieved (-for example, 1000 lines on an Allah format ( - 29.7 21 cm)) in -the horizontal as well as in the vertical direction. In the Figure -the nine light conductors Al I By 3 and C1 3 -to be irradiated are subdivided into try groups of -three adjacently situated legality conductors. The groups ox light conductors Al 3, By 3 end C1 3 are alternately end periodically irradiated in a pulsed manner by means of light sources IDEA which are connected to a decoding circuit DEC. The inputs of -the decoding circuit DEW are connected to outputs of binary counter C which periodically receives control pulses clue.
From the relevant counter position, -the circuit DEW deter-mines itch source LD1, LD2 or LD3 '(actually, which group of light conductors Al 3, By 3 or C1 3) must be activated.
It will be apparent that with each light conductor Al 3, By 3 and Cal 3 to be irradiated there is associated an outgoing light conductor Aye, B1_3 and 1-3 receive light only from -the associated irradiated light conductor (see Figure I The outgoing light conductors Aye By 3 and C1 3 are also subdivided into three groups of three light conductors each; the light conductors bearing an index 1 (Al, By and C1) belong -to -the first group, whilst the light conductors bearing -the indices 2 Tingly 9 l5.3.~
nil 3 (A, By, C2 allot A, By, C3, respectively form par-t of the second group end the -third group, respectively.
Each of these groups is connected to a detector transistor Do, D,, and Do. when the detector -transistor Do detects a legality pulse after -the emission of a light pulse by the light source LO , a -transfer of light has taken place from a light conductor of the group A' to a light conductor of the group bearing tile index 1. Inn a light pulse is detected by the detector -transistor Do after the light source LD2 has lo errlitted a light pulse, a transfer of light has taken place from a light conductor of the group C' to a light conductor of -tile group bearing the index 2. The combination of the activation data (= -the position of the entry C) of the light sources LD1 3 and the data of the detected light pulse (detector Do 3) defines -the exact position of the light -transfer (at least in a direction x for -the device shown in Figure pa).
I-t is useful to have -the position available in -the form ofabinary number computer input). The outputs of the detector transistors Do I consequently are eon-netted to an encoding circuit DBC which produces a binary number on output terminals To and To 9 said binary nwnber corresponding to the index number of -the -transistor which detects a light pulse. The connections DC in Figure pa are actually formed by diodes DC which are partly shown in detail in Figure 5b. when Do is conductive, -the output terminals To and TO are "high". I-t will be apparent that -the oUtpllts O r the counter and -those of the encoding circuit DBC present a binary number which is an exact translation into a position of -the -transfer of light on the writing tablet 'ion, The described example involving three groups of three light conductors each is merely an example.
In reality, for example in each layer 32 groups of 32 light conductors are used in -tile x-direction as well as in the y-direction (for the ALLAH format, -this offers a resolution of better than Owe x Owe men). For a number of N x N
Pi PHN.IO.6~!~ IO 15 oily post owns to be detected, only ON legality sources end only I light detectors are required. When N equals 32 (above example), the counter C must be capable ox mounting up -to a Whitehall of 5 bitts (To - To) end the decoding circuit DO
should comprise Tao "one-o-u-t-of-six-teen" decoding circuits.
The encoding circuit DO will comprise five outgoing lines (To - T10) because a translation of the member owe -to the binary system is required. The position x will then be given as a ten bit number (To - T10) and so will a position for the y-eoordinate. It is to be no-ted that the activation of the light sources for the direction as well as the y-clirection can be simultaneously performed, so -that a part (formed by the counter C) of the number of the x-position in a point (x, y) will be -the same as a corresponding par-t of the number of -the y-position in -that point (zoo).
The coordinates of the point (x, y) can, therefore, be exactly defined by means of` one Betty word (in -the above example). It is also -to be noted -that the frequency of the 20 clock pulses elk is decisive for -the maximum writing and drawing speed on -the writing tablet for which -the maximum resolution is still maintained.
Position sensor.
The invention relates to a position sensor for worming, using optical means, an electric signal which is dependent of the position of an end of a pointing member weakly bears on the position sensor.
A position sensor of this kind is known from a publication by S. Tumor et at in Applied Optics, Vol. 19, No. 11, June 1, 19~0, The described sensor is formed by a rectangular flat plate which is surrounded by oppositely situated rows of light emitting and detecting diodes.
10 An end of a pointing member, for example, a stylus positioned on the flat plate interrupts the light which is emitted by the rows of diodes in a given sequence and which is detected more or less by the oppositely situated diodes. Each photo diode should be connected -to a so-called 15 coherent detection circuit; consequently, a sizable position sensor offering a suitable resolution is an ox-pensive device. Furthermore, the resolution and the absolute size of -the position sensor are restricted by -the low directional sensitivity of the photo diodes and also by the 20 minimum signal-to-noise ratio required.
I-t is an object of -the invention to provide a position sensor which allows for a comparatively high resolution in a large surface area to be chosen. It is a further object of the invention to provide a position sensor 25 whose electronic circuits are very simple and limited in Sue.
To this end, a position sensor in accordance with the invention is caricatured in -that it comprises at least two layers of light conductors which are embedded in a 30 light conducting carrier material whose refractive index is lower than the refractive index of -the light conductors, the light conductors in both layers extending parallel -to one another, the spacing of -the light conductors in each '7 Ply 4 2 15.3.811 layer being larger than the dustiness between -two light con-cluctors which are substantially oppositely situated in the two layers, the light conductors in a firs-t layer being connected -to a light source whilst the light conductors in the second layer are connected to a light detector. In -the force sensitive position sensor a position of a tip of a writing tool is determined by the occurrence of light trays-for between two light conductors. It follows -therefrom -that a very high resolution can be achieved by using very thin 10 light conductors (diameter in the order of magnitude of a few sum), and -that the position of the -tip of -the writing -tool is determined by detection of the light transfer between -two of such light conductors.
The invention will be described in detail herein-15 after with reference to a number of embodiments which are shown in the drawing therein Figure 1 shows -the principle used in the position sensor in accordance with the invention, Figures pa and b diagrammatically show -the 20 construction of -the position sensor in accordance with the invention, Figure 3 diagrammatically shows an opto-mechanical position decoding device for a writing -tablet in accordance with the invention, Figure shows an optomechanical position encoding device, and Figures pa and b show an optoelectronic position decoding circuit for a position sensor in accordance with the invention, as well as a de-tail thereof.
Figure 1 shows -two glass or plastics light conductors 1 and 2 which extend in -the y-direction of a Cartesian system of coordinates x-y-z. The light conductors 1 and 2 are embedded in a carrier 3 of a transparent material end are situated one over the other a-t a distance of 35 approximately from 5 -to 10/um, viewed in -the z-clirec-tion.
The conductors 1 and 2 themselves have a diameter of from 3 -to 5 sum. All dimensions are given by way of example and are, of course, depellden-t on the wavelength of the light '7 PIN . l o, Go I 3 1 5 . 3 I
used. The retractive inc1ex of the -Iigll-t conc1uc-tors 1 end 2 is slightly haggler 1 c/O) than that of -the material of -the carrier 3 surroi~nc1ing -the light conductors I and 2. Light 5 is radiatec1 -in-to -the ligate conductor 1 by a diode 4. In normal circumstances -the light 5 will -travel -through the slight conductor 1 in order to emerge therefrom a-t the end 1' thereof. When a force F is exerted on the carrier 3 so that acutely a local geometrical deformation occurs, -the optical coupling between -the light conductors 1 anal 2 Jill change 10 anc1-the part of -the light which propagates outside -the conductor 1 Jill also change; part thereof will then pro-palate in -the conductor 2. The light 5' which emerges from an end 2' of the light conductor 2 will be detected by a photosensitive diode 6. The degree of optical coupling be-15 tweet the light conductors 1 and 2 depends in a complex manner on the light conductor configuration, dimensions, such as spacing, refractive index, refractive index profile, wavelength of -the light used, etch A model of -the phenomenon "perturbation of wave propagation and its dependence on I said parameters has already been described in Phillips Journal of research, Vol. 33, No. 5/6, 197~, pages 254-263, by D. Tjaden.
When, vocal in the direction pairs of light conductors are adjacently arranged in such a carrier 3 25 arranged over one another in the direction and extending in -the y-direction) a-t a distance I 100/um) which is large with respect -to the distance in -the z-direction I 5-10/-um) an x-position sensor is obtained which (viewed in the direction produces 7 at the area where a 30 force F is exerted on -the carrier 3, a light signal on an "outgoing" light conductor 2 when light is radiated into the associatecL light conductor 1. The carrier 3 firs-t of all serves -to maintain the light conductors 1 end 2 a-t the correct distance from one another so -that light can be 35 -transferred there between, and also serves for mechanical protection of -the light conductors.
Figure pa diagrammatically shows the construction of a position sensor. In a firs-t layer I a row of light PllN.lo.Gll4 Lo. 1 5 . '3. I
condl1ctors Rockwell extend in the y-clirection is arranged in the x-direction. In a layer II there is arranged a second row of legality conductors which extend parallel -to the light conductors in the furriest layer I. Each light conductor in tile slayer I is situated exactly over (viewed in the z-direction) a light conductor in the layer II as appears also from Figure 1. The layers III and IV in Figure pa are identical to the layers I and II with -the exception of` the direction (x-direction). The light conductors in -the layers 10 III and IV are directed a-t right angles to the light con-doctors in -the layers I and II. If necessary, the spacing of the light conductors in the layers III and IV differs from that in the layers I and II. The ends of -the light-conductors 2x of -the layer II are bundled and fed to a 15 photodiocle 6x. Similarly, the ends of the light conductors my of -the layer IV are bundled and fed to a photo diode my.
The ends of` the ligtlt conductors 1x and lye of -the layers I and III, respectively however, are adjacently arranged in a row in the correct sequence. When a force F is exerted on the stack of the four layers I -to IV in a point p, the diodes 6x and/or my detect, when the light conductors 1x and my are alternately irradiated, a light signal emerging from the light conductors 2x and my if -those light conductors 1x and/or my are irradiated which extend exactly underneath -the point p or Lucia are situated sufficiently near this point. I-t will be apparent that such a position sensor allows for a high resolution (Jo 10 linesmen and that i-t is very suitable as a writing or drawing table-t, because the light conductors allow for such a spacing and the -tip of customary writing -tools (for example, a ballpoint) exerts a force on a surface which has a diameter in -the same order of magnitude.
Figure 2b is a diagrammatic sectional view (not to scale) of the layer-wise composition of the position sensor or the writing tablet shown in Figure aye.
The -thickness of the carriers 3x and my in which the layers I and II, III and IV, respectively, are situated alnounts P~1~.1.). Glue 5 1 5. 3. Jo to 100/l1m. Each of the carriers 3x and my comprises -three layers: a first layer 31 and a thirc1 layer 33, each having a thicklless of illume, and a second layer 32 which has a thickness of sum and which is enclosed by -the first and the third layer. The conductors 1x in -the layer 31 and the conductors 2x in the layer 33 are arranged at -the sides of the layers 31 and 33 which adjoin the second layer 32.
Siniilarly, -the conductors lye and my are arranged on both sides of the enclosed layer 32 of -the carriers my. It is 10 alternatively possible to form conductors in the second layer 32. Use is -then made of a second layer (for example, having a thickness of 15/um) in which light conductive tracks are formed on both sides by means of known techniques (for example, see the book "Planar Optical Wave Guides and 15 Fires", Chapter 3, 1977, bug. Urger, published by Clarendon Press, oxford). Because -the position sensor or the writing -tablet has a thickness of only a few tenths of a millimeter and because i-t is transparent, the sensor or -the writing tablet, when made of an elastic material, 20 can be arranged directly against a display screen of, for example a computer -terminal so that direct interaction with the computer is possible.
As has already been statical, the position of the force F exerted can be determined by irradiating the 25 light conductors I and my one by one and by detecting the light intercepted by one of each group of light conductors 2x and my When the Light conductors lo and lye are periodic-ally irradiated, -the instant at which light is detected a-t an exit of the light conductors 2x and my within such a 30 period will be decisive for -the position I.
Figure 3 diagrammatically shows an embodiment of a position detection mechanism of the described kind.
The light conductors lo are arranged in a row and are irradiated one by one by a light beam which is reflected to the ends of -the light conductors lo via a rotating prism S. In order to know -the position of the light beam (actually the position of -the irradiated light conductor), the prism S is mechanically coupled -to a pulse generator PG.
-134~
PUN G I 5. 3. I
The pulse generator PUG comprises a disc TO which rotates in synchronism w-itI-I-tlle mirror S end which generates pulses in cooperation with a photo diode and a light emitting diode FED, said pulses being applied to a counter I The position 5 of the counter I is a measure of -the position of the prism S and hence a measure of the position of the light conductor 1x being irradiated at the relevant instant. When a force is exerted on the position sensor or thwarting tablet 10 in a point p, a detection transistor D receives a light pulse via the bundled outgoing light conductors 2x if the light conductor 1x extends underneath the point I. The tray-sister D subsequently applies a control pulse -to a buffer circuit B , with the result -that -the position of the counter Ox is transferred to the buffer By. The buffer By contains -the counter position in which a transfer of light took place from one of the light conductors Ix to 2x, so that it in-dilates the position (in the x-clirection). Evidently, for the determination of the position use can be made of a similar opto-mechanical decoding device, Instead of a rotating prism S end the pulse generator Pause can alter-natively be made 0~7 for example a piezoelectric crystal on which a mirror is mounted in order to irradiate the row of light conductors 1x. The control. voltage for the pus-electric crystal is -then a measure of the position of the light beam Jo , and hence of the position of the irradiated light conductor 1x. Obviously, the en-tire irradiation and detection mechanism can be completely reversed, the bundled light conductors 2x then being irradiated and the light conductors 1x being sequentially sampled for the deter-munition of the position of -the pressure point p. To this end it is merely necessary to arrange the transistor D in the location of the light source L and vice versa; of course, the output of the transistor D remains connected to the 35 control input of the buffer By.
Figure Lo shows a further embodiment of a position duckling device for a position sensor 20 in accordance with the invention. The light eondLIctors 1x of the first layer PING 7 l5.3.Sl~
are bundled end ore irradiated by a light-emittlng diode ED.
Tire outgoing light conductors 2x old the position sensor 20 are arranged in a row which ex-terlcls transversely of a propagation direction V of a photosensitive tape 30 which -trowels at a speed 'I , the ends of -the light conductors 2x being directed perpendicularly to -the tape surface. The The light pulses emetically by the diode LO (emission frequency f) produce exposed (colored) spots on the tape 30 with a spacing I viewed in -the propagation direction V.
The position of an exposed spot on -the tape 30 (viewed transversely of -the direction V) depends on the position P
on the position sensor 20 in which a force is exerted.
For the sake of clarity, on the sensor 20 there is shown a curve 21 on -which -there are indicated points P which 15 produce an exposed spot P' on the -tape 30 when the curve 21 is drawn on the sensor 20 by means of a writing tool.
It is -to be noted -that, when the tip of the writing -tool is held stationary during drawing, light spots are continuously written in -the same position (viewed transversely of the 20 direction V); by way of example, in Figure -the writing -tool has been held stationary at tile beginning as well as at the end of -the curve 21 9 -thus producing the points P'' and P''', respectively, on the -tape 30. I-t will be apparent that yin Figure only -the coordinate is defined. The y-coordinate associated with each x-coorcdina-te can be deter-mined in a similar manner. I-t is useful -to arrange the no of ends of the light conductors my in the prolongation of the row of light conductors 2x, so -that -the x-coordinate as well as the associated y-coordinate can -thus be defined on -the -tape 30 on a line which extends -transversely of -the direction V. A -tape 30 thus formed can be used for data input for computer equipment in the same way as a convent -tonal punched -tape.
Figure 5 shows a preferred embodiment of a position sensor or writing tablet 100 in accordance with -the invention. Again only a one-dimensional position PUN. G 'I 'I S 1 5 . 3 . I
clutter anion is represented; a -two-climensionl:L position determinatioll can be performec1 by doubling -the components Shelley, the ac1cled group of components being connected -to groups of fight conductors which are directed -transversely 5 of the fight conductors Al 3 end Allah; B1_3 an 1-3 Of 3 end Of 3 shown in Figure I The writing -tablet 100 and the associated components do not comprise moving parts (as yin -the Figures 3 and 4) end produce digital electric output signals on outputs To Lo which are suitable or 10 direct input into a computer. The incoming end outgoing light conductors Al 3, By 3' C1 3 end Aye, B1_3 and C1_3~
respectively, are subdivided in-to groups in a special way so -that the number of Light emitting diodes LID 3 and the number ox detectors Do 3 can remain limited illicit a high 15 resolution can s-till be achieved (-for example, 1000 lines on an Allah format ( - 29.7 21 cm)) in -the horizontal as well as in the vertical direction. In the Figure -the nine light conductors Al I By 3 and C1 3 -to be irradiated are subdivided into try groups of -three adjacently situated legality conductors. The groups ox light conductors Al 3, By 3 end C1 3 are alternately end periodically irradiated in a pulsed manner by means of light sources IDEA which are connected to a decoding circuit DEC. The inputs of -the decoding circuit DEW are connected to outputs of binary counter C which periodically receives control pulses clue.
From the relevant counter position, -the circuit DEW deter-mines itch source LD1, LD2 or LD3 '(actually, which group of light conductors Al 3, By 3 or C1 3) must be activated.
It will be apparent that with each light conductor Al 3, By 3 and Cal 3 to be irradiated there is associated an outgoing light conductor Aye, B1_3 and 1-3 receive light only from -the associated irradiated light conductor (see Figure I The outgoing light conductors Aye By 3 and C1 3 are also subdivided into three groups of three light conductors each; the light conductors bearing an index 1 (Al, By and C1) belong -to -the first group, whilst the light conductors bearing -the indices 2 Tingly 9 l5.3.~
nil 3 (A, By, C2 allot A, By, C3, respectively form par-t of the second group end the -third group, respectively.
Each of these groups is connected to a detector transistor Do, D,, and Do. when the detector -transistor Do detects a legality pulse after -the emission of a light pulse by the light source LO , a -transfer of light has taken place from a light conductor of the group A' to a light conductor of the group bearing tile index 1. Inn a light pulse is detected by the detector -transistor Do after the light source LD2 has lo errlitted a light pulse, a transfer of light has taken place from a light conductor of the group C' to a light conductor of -tile group bearing the index 2. The combination of the activation data (= -the position of the entry C) of the light sources LD1 3 and the data of the detected light pulse (detector Do 3) defines -the exact position of the light -transfer (at least in a direction x for -the device shown in Figure pa).
I-t is useful to have -the position available in -the form ofabinary number computer input). The outputs of the detector transistors Do I consequently are eon-netted to an encoding circuit DBC which produces a binary number on output terminals To and To 9 said binary nwnber corresponding to the index number of -the -transistor which detects a light pulse. The connections DC in Figure pa are actually formed by diodes DC which are partly shown in detail in Figure 5b. when Do is conductive, -the output terminals To and TO are "high". I-t will be apparent that -the oUtpllts O r the counter and -those of the encoding circuit DBC present a binary number which is an exact translation into a position of -the -transfer of light on the writing tablet 'ion, The described example involving three groups of three light conductors each is merely an example.
In reality, for example in each layer 32 groups of 32 light conductors are used in -tile x-direction as well as in the y-direction (for the ALLAH format, -this offers a resolution of better than Owe x Owe men). For a number of N x N
Pi PHN.IO.6~!~ IO 15 oily post owns to be detected, only ON legality sources end only I light detectors are required. When N equals 32 (above example), the counter C must be capable ox mounting up -to a Whitehall of 5 bitts (To - To) end the decoding circuit DO
should comprise Tao "one-o-u-t-of-six-teen" decoding circuits.
The encoding circuit DO will comprise five outgoing lines (To - T10) because a translation of the member owe -to the binary system is required. The position x will then be given as a ten bit number (To - T10) and so will a position for the y-eoordinate. It is to be no-ted that the activation of the light sources for the direction as well as the y-clirection can be simultaneously performed, so -that a part (formed by the counter C) of the number of the x-position in a point (x, y) will be -the same as a corresponding par-t of the number of -the y-position in -that point (zoo).
The coordinates of the point (x, y) can, therefore, be exactly defined by means of` one Betty word (in -the above example). It is also -to be noted -that the frequency of the 20 clock pulses elk is decisive for -the maximum writing and drawing speed on -the writing tablet for which -the maximum resolution is still maintained.
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A position sensor for forming, using optical means, an electric signal which is dependent on the posi-tion of an end of a pointing member which bears on the position sensor, said position sensor comprises at least two layers of light conductors which are embedded in a light-conducting carrier material which refractive index is lower than the refractive index of the light conductors, the light conductors in both layers extending parallel to one another, the spacing of the light conductors in a same layer being at least a factor five larger than the dis-tance between two light conductors which are substantially oppositely situated in the two layers, the light conductors in a first layer being connected to a light source while the light conductors in the second layer are connected to a light detector.
2. A position sensor as claimed in Claim 1, wherein the light detector comprises several detector elements, the light conductors of a layer being subdivided into a corres-ponding number of groups, each of the groups of light con-ductors being connected to an associated detector element.
3. A position sensor as claimed in Claim 2, wherein a first layer of light conductors is subdivided into a number of equally large groups of adjacently situated light conductors, said number being equal to or an integer number of times larger than the number of light conductors in each group, a second layer of light conductors being subdivided into the same number of groups, a first group of the second layer being composed of the light conductors which are situated opposite a first light conductor of each group of the first layer, an nth group of the second layer being composed of the light conductors which are situated oppos-ite the nth light conductors of each group of the first layer, where 1?n?N, N being the number of light conduc-tors of a group of the first layer.
4. A position sensor as claimed in Claim 2, wherein each group of light conductors is connected, together with a corresponding group of light conductors in a different layer, to the same light source.
5. A writing table comprising an input surface on which there is located a position sensor for forming, using optical means, an electric signal which is dependent on the position of an end of a pointing member which bears on the input surface, said position sensor comprises at least two layers of light conductors which are embedded in a light-conducting carrier material which refractive index is lower than the refractive index of the light conductors, the light conductors in both layers extending parallel to one another, the spacing of the light conductors in a same layer being at least a factor five larger than the distance between two light conductors which are substantially oppositely situated in the two layers, the light conductors in a first layer being connected to a light source while the light conductors in the second layer are connected to a light detector.
6. A display device comprising a display field adja-cent of which there is located a position sensor for form-ing, using optical means, an electric signal which is depending on the position of a pointing member which bears on the display field, said position sensor for forming, using optical means, an electric signal which is dependent on the position of an end of a pointing member which bears on the position sensor, said position sensor comprises at least two layers of light conductors which are embedded in a light-conducting carrier material which refractive index is lower than the refractive index of the light conductors, the light conductors in both layers extending parallel to one another, the spacing of the light conductors in a same layer being at least a factor five larger than the distance between two light conductors which are substantially oppos-itely situated in the two layers, the light conductors in a first layer being connected to a light source while the light conductors in the second layer are connected to a light detector.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL8301298A NL8301298A (en) | 1983-04-14 | 1983-04-14 | POSITION RECORDER. |
| NL8301298 | 1983-04-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1228407A true CA1228407A (en) | 1987-10-20 |
Family
ID=19841696
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000451789A Expired CA1228407A (en) | 1983-04-14 | 1984-04-11 | Position sensor |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4609816A (en) |
| EP (1) | EP0122673B1 (en) |
| JP (2) | JPS59198305A (en) |
| CA (1) | CA1228407A (en) |
| DE (1) | DE3467264D1 (en) |
| NL (1) | NL8301298A (en) |
Families Citing this family (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3447122A1 (en) * | 1984-12-22 | 1986-06-26 | Messerschmitt-Bölkow-Blohm GmbH, 2800 Bremen | MEASURING ARRANGEMENT FOR DETECTING CRACKS IN TEST UNITS |
| US4733068A (en) * | 1986-04-07 | 1988-03-22 | Rockwell International Corporation | Crossed fiber optic tactile sensor |
| GB2199938A (en) * | 1987-01-20 | 1988-07-20 | De La Rue Syst | Force detection assembly |
| GB8702302D0 (en) * | 1987-02-02 | 1987-03-11 | Parks J R | Capturing information in drawing & writing |
| US5013908A (en) * | 1988-11-28 | 1991-05-07 | Kaman Sciences Corporation | Break detection system using optical fibers having unique frequency modulated light |
| US4936649A (en) * | 1989-01-25 | 1990-06-26 | Lymer John D | Damage evaluation system and method using optical fibers |
| US5567932A (en) * | 1995-08-01 | 1996-10-22 | Sandia Corporation | Geomembrane barriers using integral fiber optics to monitor barrier integrity |
| US5913245A (en) * | 1997-07-07 | 1999-06-15 | Grossman; Barry G. | Flexible optical fiber sensor tapes, systems and methods |
| CA2273113A1 (en) * | 1999-05-26 | 2000-11-26 | Tactex Controls Inc. | Touch pad using a non-electrical deformable pressure sensor |
| US6776049B2 (en) | 2001-12-07 | 2004-08-17 | Alliant Techsystems Inc. | System and method for measuring stress at an interface |
| US7043997B2 (en) * | 2003-07-09 | 2006-05-16 | Cherry Corporation | Seat for sensing a load |
| EP1668482A2 (en) * | 2003-09-22 | 2006-06-14 | Koninklijke Philips Electronics N.V. | Touch input screen using a light guide |
| DE102008037861A1 (en) * | 2008-08-15 | 2010-03-18 | Siemens Aktiengesellschaft | Optical push button sensor |
| TWI536702B (en) | 2010-07-15 | 2016-06-01 | Ｚ動力能源有限責任公司 | Method and apparatus for recharging a battery |
| EP2439619B1 (en) * | 2010-09-17 | 2019-07-17 | BlackBerry Limited | Touch-sensitive display with optical sensor and method |
| US9223431B2 (en) | 2010-09-17 | 2015-12-29 | Blackberry Limited | Touch-sensitive display with depression detection and method |
| US9513737B2 (en) | 2010-09-17 | 2016-12-06 | Blackberry Limited | Touch-sensitive display with optical sensor and method |
| EP2439620B1 (en) * | 2010-09-17 | 2018-04-11 | BlackBerry Limited | Touch-sensitive display with depression detection and method |
| WO2013115770A1 (en) * | 2012-01-30 | 2013-08-08 | Empire Technology Development Llc | Systems, materials, and methods for a mechanical stress activated interface using piezo-optical components |
| WO2014110477A2 (en) | 2013-01-11 | 2014-07-17 | Zpower, Llc | Methods and systems for recharging a battery |
| WO2015108531A1 (en) | 2014-01-17 | 2015-07-23 | Empire Technology Development Llc | Aligning guide using pressure-sensitive index change elastomer |
| WO2015163896A1 (en) | 2014-04-24 | 2015-10-29 | Empire Technology Development Llc | Rewritable photorefractive polymer layer for optical fiber coupling |
| CA2983019A1 (en) | 2015-04-29 | 2016-11-03 | Zpower, Llc | Temperature dependent charge algorithm |
| US11199660B2 (en) * | 2018-11-20 | 2021-12-14 | University Of Louisville Research Foundation, Inc. | Soft optics with mechanically tunable refractive index |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU711518A1 (en) * | 1976-07-22 | 1980-01-25 | Войсковая часть 60130 | Optical filter |
| JPS5621279A (en) * | 1979-07-31 | 1981-02-27 | Sumitomo Electric Ind Ltd | Tablet |
| US4320292A (en) * | 1979-08-22 | 1982-03-16 | Nippon Telegraph And Telephone Public Corporation | Coordinate input apparatus |
| US4486095A (en) * | 1980-06-27 | 1984-12-04 | Movement Techniques Limited | Movement measuring apparatus and landmarks for use therewith |
| US4480182A (en) * | 1982-03-16 | 1984-10-30 | Burroughs Corporation | Single plane optical membrane switch and keyboard |
-
1983
- 1983-04-14 NL NL8301298A patent/NL8301298A/en not_active Application Discontinuation
-
1984
- 1984-04-06 US US06/597,762 patent/US4609816A/en not_active Expired - Fee Related
- 1984-04-11 CA CA000451789A patent/CA1228407A/en not_active Expired
- 1984-04-11 JP JP59071027A patent/JPS59198305A/en active Pending
- 1984-04-11 EP EP84200505A patent/EP0122673B1/en not_active Expired
- 1984-04-11 DE DE8484200505T patent/DE3467264D1/en not_active Expired
-
1991
- 1991-11-14 JP JP093474U patent/JPH0571705U/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0571705U (en) | 1993-09-28 |
| EP0122673B1 (en) | 1987-11-04 |
| US4609816A (en) | 1986-09-02 |
| NL8301298A (en) | 1984-11-01 |
| EP0122673A1 (en) | 1984-10-24 |
| JPS59198305A (en) | 1984-11-10 |
| DE3467264D1 (en) | 1987-12-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1228407A (en) | Position sensor | |
| JP3079004B2 (en) | Simplified digital pad sensor | |
| EP0610262B1 (en) | See-through digitizer with clear conductive grid | |
| KR960013424B1 (en) | Display apparatus with integral input | |
| US4177354A (en) | Graphic communications apparatus | |
| US5027115A (en) | Pen-type computer input device | |
| CN100516988C (en) | Display,display system ,electric device and panel,and methods for manufacturing the same | |
| KR100451773B1 (en) | Touch Panel in Digital Resistive Type | |
| US5170127A (en) | Capacitance imaging system using electro-optics | |
| US20010026268A1 (en) | Coordiante input and detection device and information display and input apparatus | |
| JPS62138731A (en) | Pressure response type device | |
| US20100171717A1 (en) | Optical interactive panel and display system with optical interactive panel | |
| JP2001154791A (en) | Touch panel | |
| EP0672996B1 (en) | Input panel avoiding interference pattern | |
| JPS61188515A (en) | Optical touch panel switch | |
| US4281313A (en) | Barooptical verification apparatus | |
| WO2010079966A2 (en) | Touch panel | |
| US6781572B2 (en) | Optical pointing device, control method thereof and computer program product recording the same | |
| US4194084A (en) | Aperture capacitor pickup | |
| JP3056622B2 (en) | Position detection device | |
| CA2104227A1 (en) | Graphics surface assembly with calibrating memory device | |
| US8269742B2 (en) | Manufacturing method of coordinate position detecting device | |
| KR19990038943A (en) | Apparatus for inputting absolute coordinate on screen according to irradiation of concentrated light | |
| JP2636228B2 (en) | Display device with input function | |
| US8552732B2 (en) | Apparatus for measuring conductive pattern on substrate |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |