EP0050294A1

EP0050294A1 - Method of making an electrode construction and electrode construction obtainable by this method

Info

Publication number: EP0050294A1
Application number: EP81108245A
Authority: EP
Inventors: Masanori Watanabe; Kinzo Nonomura; Yoshinobu Takesako
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 1980-10-20
Filing date: 1981-10-12
Publication date: 1982-04-28
Also published as: DE3175837D1; EP0050294B1

Abstract

In bonding fine electrodes (12a1, 12a2, 12b...) to other electrodes (6 and 1) with insulated relation among them, bonding is made by using two layers of crystallizable sealing glass (a low temperature glass frit). That is, a first layer (3) of crystallizable sealing glass is applied on said other electrodes (6 and 1) and fired by a high temperature to make the layer be crystallized to form a hardened spacer, and then a second layer (38) of crystallizable sealing glass is further applied on the first layer (3), followed by glazing at a lower temperature than the high temperature, thereafter the fine electrodes (12a1, 12a2, 12b...) are pressed on the layers and both are heated resulting in crystallization and hardening of the second layer (17).

Description

Several proposals have been made on multiple electron beam type flat shaped picture display device, for example in the United States Patent Specification No. 3,935,500 and SID 78 Digest pp. 122 to 127. Furthermore, in order to obtain higher grade picture having larger number of picture elements three of the inventors of the present invention have invented and proposed a simultaneous scanning multiple electron beam type picture display apparatus described in the specification of the Japanese Patent Application Sho 53-106788 filed on August 30, 1978 (not yet examined) and also described in the specification of the United States Patent No. 4,227,117 patented on October 7, 1980. This apparatus can have very large number of the picture element in comparison with number of electron extracting apertures of its control electrode.
The structure of picture image display apparatus of the above-mentioned described invention is shown in FIG. 1 which is an exploded view of the principal part of the above-mentioned apparatus. The apparatus comprises, as shown from the upper part to the lower part in FI_G. 1, an isolation electrode 200 having a plural number of isolation walls 201 to define oblong isolated spaces 202, a row of predetermined number M (e.g. M=15) of parallel disposed linear thermionic cathodes 1 (i.e., line cathodes, each of which comprises a linear filament line to be heated by a low voltage, e.g., D.C. 10 V and electron emissive oxide coating thereon, and hereinafter is referred to as linear thermionic cathode) each being disposed in the isolated spaces 202, an extractor electrode 300 having a predetermined number N (e.g. N=107) of electron beam passing apertures 300a disposed in rows below the linear thermionic cathodes 100, a row of control electrodes 400 for controlling beam intensity disposed parallelly in a direction perpendicular to those of said linear.thermionic cathodes 100 each having electron beam passing openings 400a below the apertures 300a, an electron beam forming electrode 500 having electron beam passing openings 500a below the openings 400a, a row of vertical deflection electrodes comprising pairs of common-connected first electrodes 600 and common-connected second electrodes 600', a row of horizontal deflection electrodes comprising pairs of common-connected first electrodes 700 and common-connected second electrodes 700', an electric field shielding electrode 800, an anode 900 of vapor- deposited thin aluminum film, and a phosphor screen 1000 formed on a face panel 1100 of a vacuum enclosure and under said anode 900. Every electron beams e, e ... pass through deflection spaces 620, 620 ... and 720, 720 ... defined by the deflection electrodes pairs 600, 600' ... and 700, 700' ... disposed regularly in the same order with respect to every electron beams as shown in FIG. 1.
In the operation of such multiple electron beam type flat display apparatus described in the above-mentioned specifications, scannings of beam spots on the phosphor screen are made in the known line-at-a-time type scanning, wherein ordinary time-sequential image signal is converted into a plural number of parallel signals. For example, by taking a case to display an image field raster having numbers of picture elements of 240 (in vertical direction) times 321 ( in horizontal direction), with regard to the horizontal scanning of the beam spots the raster is divided into a plural number N of vertically oblong sections, wherein the horizontal scannings are carried out parallelly in all of N sections. Then, each section has picture elements of n=
N in the horizontal direction. For example, when the number N of the vertical sections is 107, the number n of picture element in each section is 3. For such example, 107 beam spots are produced from each linear thermionic cathode and 107 control electrodes are provided in order to control the 107 electron beam intensities. In the apparatus, the horizontal scanning is made by using saw-tooth wave having a horizontal scanning period H applied to the horizontal deflection electrode and in a manner that all the N beam spots are deflected simultaneously to scan in the same direction taking one horizontal scanning period H. The horizontal scanning period H is equal to the horizontal scanning period of the ordinary time sequential television signal. In order for attaining such line-at-a-time-scanning, the ordinary time sequential image signal is preliminarily converted into the N parallel signals of the line-at-a-time type, each signal thereof comprising time sequential elements for three picture data.
The vertical scanning of the described apparatus is made by dividing the raster into a plural number M of horizontally oblong sections, and at first in the first section, for example in the uppermost section, the plural number of beam spots, which simultaneously scan, also scan vertically (downwards). When the vertical scanning in the first section is over and all the beam spots reach the bottoms of the first horizontally oblong sections, then the forming of electron beams from the electron from the first linear thermionic-cathode ends and the forming of electron beams from the electrons from the second linear thermionic cathode starts, and the vertical scannings of the beam spots start in the second horizontally oblong section and scan downwards in the same way as in the first section. The vertical scanning is made thus downwards to the bottom or M-th section by applying a saw-tooth wave having a period M, where V is the vertical scanning period of the ordinary television signal. For the above-mentioned example of the raster having the number of vertical picture element of 240, when the number M of the horizontally oblong sections is 15, each of the section has the horizontal scanning lines of a number of m=
=16. That is to say, the example apparatus uses ₁₅ linear thermionic cathodes, and each cathode vertically scans to produce 16 horizontal scanning lines.
In such picture display apparatus, as elucidated in reference to FIG. 1, a high precision structure is required in positional relations and gaps between parallel electrodes, in order to obtain accurate scanning and beam current controlling necessary for high grade picture.
In general, the electrodes other than cathodes of such flat type picture display apparatus are made of Ni-Cr-Fe alloy, and these electrodes have considerable sizes and are assembled with predetermined narrow gaps by utilizing insulating gap spacer substrates of glass or ceramic, and bonding of the above-mentioned members are made by using sealing glass (i.e., low melting temperature glass frit). In such construction punching on the insulating gap spacer of glass or ceramic requires difficult and rather expensive working, and furthermore, such glass or ceramic substrate has different thermal expansion coefficient from the electrode material inducing strain or crack of such insulating gap spacer substrate, leading to unstable or unreliable operations of the display apparatus.

Summary of the Invention

The present invention purports to improve the above-mentioned problem of the conventional flat type picture display apparatus. The present-invention enables to bond electrodes with high accuracy and without problem of strain or crack of insulating gap spacers.
The bonding is made by using two parts of crystallizable sealing glass, namely a first part applied on an electrode and fired to crystallize to form hardened spacer, and a second part applied on the electrode or on the first part, the second part bonding the electrodes. Thus the bonded electrode construction includes a plural of electrodes, insulating gap spacers of first part of crystallizable sealing glass spacing a predetermined gap between the electrodes and bond of second part of crystallizable sealing glass bonding the electrodes.

Brief Explanation of the Drawings

FIG. 1 is an exploded perspective view of a general example of a multiple cathode type flat picture image display apparatus.
FIG. 2 is an exploded perspective view for elucidating a step of an example embodying the present invention.
FIG. 3 is an exploded perspective view for elucidating a step of another example embodying the present invention.
FIG. 3A is an exploded perspective view for elucidating a step of another example embodying the present invention.
FIG. 4 is an exploded perspective view for elucidating a step of another example embodying the present invention.
FIG. 4A and FIG. 4B are front views showing two examples modified from the example of FIG. 3 or FIG. 4.
FIG. 5 is an exploded perspective view for elucidating a step of another example embodying the present invention.
FIG. 6 is a front view of assembled construction of the example of FIG. 5 seen from the direction of arrow VI of FIG. 5.
FIG. 7 is a front view of a step of a part of the construction of the example of FIG. 5 seen from the direction of arrow VII of FIG. 5.
FIG. 7A is a front view of the finished state of the construction of FIG. 7.

Description of Preferred Embodiments

Further objects and advantages are elucidated more in detail referring to the attached drawings illustrating examples of the present invention.
In FIG. 2, a first electrode 1 and a second electrode 6 having oblong through holes 2, 2 ... and 7, 7 ..., respectively, are to be assembled with a plural of oblong third electrodes 4, 4 ... having corresponding oblong through- holes 5, 5 ... inbetween. These first electrode 1, second electrode 7, and third electrode 4 are made of Ni-Cr-Fe alloy. These members are not necessarily limited to the electrodes per se, but may be any auxiliary or related member thereof, for example, supporting frame or current feeding conductor, or the like, and therefore, the word "electrode" should be taken as "electrode member" which includes the electrode as well as the above-mentioned auxiliary or related members. On a face of the first and the second electrodes 1 and 6, at the parts other than the through- holes 2, 2 ... and 7, 7 ... of the electrodes 1 and 6, respectively, pieces or strips 3, 3 ..., 8, 8 ... of a crystallizable sealing glass are formed by, for example, screen printing process. For the sealing glass, a glass frit having a low-melting point, for example, 7575W (name of good) produced and sold by Iwaki Glass Co., Ltd. of Tokyo Japan) is used. On both faces of the third electrodes 4, 4 ..., pieces or strips 38, 38 ... of crystallizable sealing glass are formed similarly to the above-mentioned strips and at the parts to corresponds thereto. Strips on either of the first and the second electrode 1, 6 or the third electrodes.4, 4 ... are then heated to such a "high temperature" that the crystallizable sealing glass of the glass frit 3, 8 or 38 heated thereby become crystallized (hereinafter this "high temperature" is referred to as "crystallizing temperature"). After such heating, the sealing glass is irreversibly crystallized, and the crystalline structure is retained even when the temperature is brought down or further raised. Then the strips on the other electrode, which has not yet heated, is then heated to such a "lower temperature" that the crystallizable sealing glass therein becomes a glaze, but not yet crystallized, and therefore will be crystallized at subsequent heating to or over the crystallizing temperature (hereinafter, this "lower temperature" is referred to as glazing temperature).
Then, by assembling the first electrode 1, the second electrode 6 and the third electrode 4 inbetween, pressing and heating them, the pieces or strips of sealing glass which have become glaze melt and bond the electrodes or electrode members all together. In this bonding step, the previously crystallized pieces of strips, which are now hardened, serves as gap spacers to define necessary gaps between the electrodes.
FIG. 3 shows a step of another example embodying the present invention, wherein a plural number of oblong electrodes 4, 4 ... are to be bonded in insulated relation on a first electrode 1. The electrodes 4, 4 ... and 1 are similar to those of the first example. In this example, however, each of the strips of the sealing glass comprises first parts 3 formed directly on the first electrode 1 and second parts 38 formed on the first parts 3. The first parts 3 are formed by, firstly applying crystallizable sealing glass powder (for example, the 7575W of Iwaki Glass Co., Ltd.) mixed with a known vehicle containing, for example, isoamyl acetate, by means of screen printing process, and secondly, after drying the mixture, firing the sealing glass powder at the crystallizing temperature of e.g. 450 to 500°C, thereby to crystallize and harden the sealing glass.
Then, the second parts 38 are applied onto the hardened strips of the first parts 3, by means of, for example, the similar screen printing process to that of the first parts 3 followed by a glazing step. The same kind of crystallizable sealing glass as that of the first parts 3 is usable for the second parts 38, but different kind crystallizable sealing glass may be used. The glazing of the second parts 38 is made by heating it to the glazing temperature of e.g. 350 to 380°C, thereby obtaining reversibly hardened strips which is durable to inadvertent scratching.
Thereafter, oblong electrodes 4, 4 ... to be bonded on the first electrode 1 are put on the latter, pressed and the above-mentioned members are heated to the crystallizing temperature of the crystallizable. sealing glass of the second parts 38. Then, the crystallizable sealing glass is melt and changes to the crystallized state, and the oblong electrodes 4, 4 ... are firmly bonded to the first electrode 1 with accurate gap defined by the thickness of the first parts 3. In the above-mentioned process, the glazing of the second parts 38 is preferable for the durability thereof, and reliability of the manufactured apparatus, but this may be dispensed with if scratching or damaging of the second parts 38 is not liable to occur.
FIG. 3A shows a modified example where the second parts 38 of crystallizable sealing glass are disposed at the side of the first parts 3. In this case, in order to ensure reliable bonding, the thickness of the second parts 38 should be thicker than the first part 3; and for other matters, descriptions for the example of FIG. 3 is similarly applicable to this example.
FIG. 4 shows another example, wherein different from the example of FIG. 3, the crystallizable sealing glass strips 3 and 38 are divided into short pieces, and other parts are substantially the same to the example of FIG. 3. By means of such divided strips construction, even when difference of thermal expansion coefficient between the electrode and the strips of sealing glass shows a considerable value, there is no undesirable strain or bending of each electrode and of the assembled electrode construction.
FIG. 4A is a front view of an example which is a modification of the example of FIG. 3 or FIG. 4. In the constructions of FIG. 3 or FIG. 4, the largest gap space obtainable by the gap spacer is about 500 µm, and when a gap space larger than 500 µm, accurate and uniform gap space can not be formed. The construction of FIG. 4A shows an improved construction which can afford a desirable large gap by means of cascade gap spacer construction, where a metal spacer 100 is bonded on the electrode 1 by means of the double layer construction of the crystallizable sealing glass comprising the first part 3 and the second part 38 formed by the same way as those of the examples of FIG. 3 or FIG. 4. The way of FIG. 2 can be also applicable. Then another two layers of the first part 3 and the second part 38 are formed on the metal spacer 100 in the same way, and by this latter double layered sealing glass, the electrode 4 is bonded to the spacer 100, and resultantly to the electrode 1.
FIG. 4B is a front view of another example which is a modification of the example of FIG. 3 or FIG. 4. In this example, the positional order of the first part 3 and the second part 38 between the electrode 4 and the spacer 100 is opposite to the case of FIG. 4A. This construction is made by forming the first part 3 and the second part 38 on the lower face of the electrode 4, instead of the upper face of the spacer 100.
FIG. 5 is an exploded perspective view of another example, and FIG. 6 is a sectional front view of the example of FIG. 5, seen from the direction of an arrow VI of FIG. 5, wherein a row of parallel wire electrodes 12al, 12a2, 12bl, 12b2, l2cl, 12c2, ... as electron beam control electrodes are bonded between a first electrode 1 and a second electrode 6 having oblong openings 2, 2 ... and 7, 7 ... respectively for passing ribbon shape electron beams. The bonding is made by means of crystallizable sealing glass strips 15, 15, 15, ..., which are formed on the lower face of the first electrode 1 and on the upper face of the second electrode 6, at such parts other than the openings 2, 2 ... and 7, 7 .... Each of the strips 15 are formed as shown by FIG. 7, which is an enlarged sectional view thereof, seen from the direction of an arrow VII of FIG. 5. The strips 15, 15 ... are formed by: Firstly applying a first part 3 of crystallizable sealing glass powder (for example, the 7575W of Iwaki Glass Co., Ltd.) mixed with a known vehicle containing, for example, isoamyl acetate, by means of screen printing process, thereafter, after drying the mixture firing the sealing glass powder at the crystallizing temperature of, e.g. 450 to 500°C, thereby to crystallize and harden the sealing glass to form a first part 3 to serve as a spacer; and then secondly forming a second part 38 by applying on the first part 3 by means of, for example, the similar screen printing process to that of the first part 3, followed by a glazing of the second part 38 by heating it to the glazing temperature of, e.g. 350 to 380°C, thereby forming the strips l5, 15 ... having sectional construction shown by FIG. 7.
Then, wires 12al, 12a2, l2bl ... as control electrodes are disposed at accurate positions on the electrode 6 by means of appropriate step, for example by using a suitable jig, and then the first electrode 1 and the second electrodes 6 are pressed to the wire electrodes 12al, 12a2 ... , and the whole parts including the strips 15, 15 ... are heated, so that the glazed second parts 38, 38 ... are melted and then crystallized and hardened thereby bonding the wire electrodes and accordingly the first and second electrodes therewith, forming an assembled electrode construction as shown by FIG. 6 (seen from the direction of arrow VI of FIG. 5) and by FIG. 7A (seen from the direction of arrow VII of FIG. 5). In this bonding, the gaps between the wire electrodes l2al, 12a2 ... and the first or second electrode 1 or 6 is accurately defined by preliminarily hardened spacer strips 3, 3 .... Of course, the first electrode 1, the second electrode 6 and the wire electrodes 12al ... inbetween are each other insulated by the strips 15 of crystallized sealing glass, consisting of the spacers 3, ... and the bonding layer 38, ..._
In case each wire electrodes are to be impressed of different voltage or signal, the hair-pin loop shaped end parts shown by the dotted line should be cut away.
On the contrary, when neighboring two wire electrodes are to be impressed of the same voltage or signal as pair electrodes, the hair-pin loop shaped end parts should be left as they are.
In the bonding step by pressing and heating the electrodes 1, 6, 12al ... together, the wire electrodes 12al, 12a2 ... should be held with a suitable tension so as to be bonded straight without sag. It is preferable to select the wire electrodes 12al, 12a2, 12bl ... having thermal expansion coefficient larger than those of the grid shaped or frame shaped first and second electrodes 1 and 6. This is for the purpose that in the finished display apparatus the wire electrodes 12al ... exhibit a desirable tension when cooled down to a room temperature or in an operating temperature of the display apparatus, which is sufficiently lower than the bonding (crystallizing) temperature.
In the above-mentioned description, the control electrodes are taken for the examples, but the application of the present invention is not limited to the control electrodes, but is applicable to the deflection electrodes, convergence electrodes or other electrodes. Furthermore, the number of electrodes to form the electrode construction is not limited to two layers or three layers as shown by the attached drawings, but constructions having more layers of electrode can be realized by embodying the present invention.
The apertures of the electrodes 2, 7 and 5 are only one example, and may be of any form.
The electrode construction in accordance with the present invention is specially suitable in accurately assembling thin electrodes of a large size formed by photolithographic etching process.

Claims

1. An electrode construction comprising:

at least two electrode members

at least a first piece of crystallizable sealing glass as a spacer disposed between said two electrode members to define space between said at least two electrode members,

at least a second piece of sealing glass as a bond disposed between said two electrode members to bond said at least two electrode members.

2. An electrode construction in accordance with claim 1, wherein
said second piece of sealing glass at least partly is superposed on said first piece of crystallizable sealing glass.

3. An electrode construction in accordance with claim 2, wherein
said second piece of sealing glass is also made of crystallizable sealing glass.

4. An electrode construction in accordance with claim 2, wherein
said first piece and said second piece are formed in strips.

5. An electrode construction in accordance with claim 2, wherein

said first piece and said second piece are formed in intermittent strips.

6. An electrode construction in accordance with claim 2, wherein

one of said electrode members is a metal plate having apertures for passing electron beams, and

the other of said electrode members is parallel wier electrodes.

7. An electrode construction in accordance with claim 6, wherein
said parallel electrodes are hair-pin shaped wire electrodes disposed in parallel each other thus forming parallel electrodes every two neighboring ones of which are common connected.

8. An electrode construction in accordance with claim 1, wherein
said first piece of crystallizable sealing glass and said second pieces of sealing glass are disposed neighboring each other on one of said electrode member.

9. An electrode construction in accordance with claim 8, wherein
said second piece of sealing glass is also made of crystallizable sealing glass.

10. An electrode construction in accordance with claim 8, wherein
said first piece and said second piece are formed in strips.

11. An electrode construction in accordance with claim 8, wherein
said first piece and said second piece are formed in intermittent strips.

12. An electrode construction in accordance with claim 8, wherein

the other of said electrode members is parallel wire electrodes.

13. An electrode construction in accordance with claim 8, wherein
said parallel electrodes are hair-pin shaped wire electrodes disposed in parallel each other thus forming parallel electrodes every two neighboring ones of which are common connected._'

14. An electrode construction in accordance with claim 1, wherein

both the electrode members have at least one of said first piece and at least one of said second piece thereon,

said second pieces on both of the electrode members are bonded on opposite faces of a metallic spacer of a predetermined thickness.

15. An electrode construction in accordance with claim 2, wherein
said second piece of sealing glass is also made of crystallizable sealing glass.

16. An electrode construction in accordance with claim 14, wherein
said first piece and said second piece are formed in strips.

17. An electrode construction in accordance with claim 14, wherein
said first piece and said second piece are formed in intermittent strips.

18. An electrode construction in accordance with claim 14, wherein

the other of said electrode members is parallel wire electrodes.

19. An electrode construction in accordance with claim 14, wherein
said parallel electrodes are hair-pin shaped wire electrodes disposed in parallel each other thus forming parallel electrodes every two neighboring ones of which are common connected.

20. Method of making electrode construction comprising the steps of:

forming at least a first piece of crystallizable sealing glass on a surface of at least one of opposing faces of electrode members,

heating said first piece until to become crystallized for serving as spacer,

forming at least a second piece of sealing glass on said surface, and

bonding said electrode members by heating and pressing them each other thereby heating to melt said second piece as bond, retaining space defined by said spacer.

21. Method of making electrode construction in accordance with claim 20, wherein
said second piece is formed in a manner to at least partly superpose on said first piece.

.22. Method of making electrode construction in accordance with claim 21, wherein
said first piece and second piece are formed in strip disposed on the face of said electrode member.

23. Method of making electrode construction in accordance with claim 22, wherein
a first one of said electrode member is a metal sheet having apertures for passing electron beams and a second electrode member is wire electrodes disposed substantially in parallel each other and to said metal sheet.

'24. Method of making electrode construction in accordance with claim 23, wherein
said wire electrodes are of a metal having larger thermal expansion coefficient than that of said metal sheet.

25. Method of making electrode construction in accordance with claim 23, wherein
said second piece is also made of crystallizable sealing glass.

26. Method of making electrode construction in accordance with claim 22, wherein
said wire electrodes are hair-pin shaped wire electrode disposed parallelly each other, and turning part of the hair-pin shaped wire electrodes are cut away, thereby isolating individual parallel wire electrodes.

27. Method of making electrode construction in accordance with claim 26, wherein
said wire electrodes are of a metal having larger thermal expansion coefficient than that of said metal sheet.

28. Method of making electrode construction in accordance with claim 26, wherein
said second piece is also made of crystallizable sealing glass.

29. Method of making electrode construction in accordance with claim 20, wherein
said first piece and said second piece are formed in intermittent strip disposed on the face of said electrode member.

30. Method of making electrode construction in accordance with claim 20, wherein
said second piece is disposed neighboring aside said first piece, and said second piece at the time prior to be heated for bonding is taller than said first piece.

31. Method of making electrode construction in accordance with claim 20, which further comprises a step of
glazing said second piece of crystallizable sealing glass by heating it to a glazing temperature which is lower than that of crystallizing it prior to said bonding.

32. Method of making electrode construction in accordance with claim 31, wherein
said first piece and second piece are formed in strip disposed on the face of said electrode member.

33. Method of making electrode construction in accordance with claim 32, wherein
a first one of said electrode member is a metal sheet having apertures for passing electron beams and a second electrode member is wire electrodes disposed substantially in parallel each other and to said metal sheet.

34. Method of making electrode construction in accordance with claim 33, wherein
said wire electrodes are of a metal having larger thermal expansion coefficient than that of said metal sheet.

35. Method of making electrode construction in accordance with claim 34, wherein
said second piece is also made of crystallizable sealing glass.

36. Method of making electrode construction in accordance with claim 32, wherein
said wire electrodes are hair-pin shaped wire electrode disposed parallelly each other, and turning part of the hair-pin shaped wire electrodes are cut away, thereby isolating individual parallel wire electrodes.

37. Method of making electrode construction in accordance with claim 36, wherein
said wire electrodes are of a metal having larger thermal expansion coefficient than that of said metal sheet.

38. Method of making electrode construction in accordance with claim 36, wherein
said second piece is also made of crystallizable sealing glass.