JPS6224893B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a directly heated composite cathode assembly suitable for use in, for example, a three-electron gun of a color picture tube.

Generally, a color picture tube has a built-in in-line three-electron gun, and this type of three-electron gun consists of a directly heated composite cathode structure, first to fourth grid electrodes, and the like.

By the way, the directly heated composite cathode structure has three
A set of cathodes is provided. In this case, a filament of the cathode is stretched between a pair of support members embedded in an insulating substrate, and a base metal plate and an electron emitting material are attached to the filament. Further, one of the pair of support members is provided with an adjusting means. When assembling the electron gun, the heights of the three sets of filaments stretched nonparallel to the first grid electrode are adjusted by the adjusting means, and the distance between the first grid electrode and the cathode, that is, the electron emitting material is adjusted to a predetermined dimension. Set to . However, it is fine if each of the three sets of filament supporting members is made with high precision, but if there is a large variation in height from the surface of the insulating substrate, the adjustment means may adjust the distance between the first grid electrode and the electron emitting material to a predetermined dimension. cannot be set. That is, the support member is embedded in the insulating substrate using glass, but in this case, when the glass is heated and melted and then solidified, tensile stress acts on the support member. As a result, 3
The support members of the set vary in height from the insulating substrate. Conventionally, the height dimensions of the three sets of support members were set using a fixing jig during manufacturing, but it was not possible to obtain satisfactory dimensional accuracy.

An object of the present invention is to provide a method for manufacturing a directly heated composite cathode assembly that eliminates the above-mentioned conventional drawbacks.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. First, a directly heated composite cathode structure manufactured by the manufacturing method of the present invention is shown in FIGS. 1 and 2. That is, FIG. 1 is a perspective view seen diagonally from above, and FIG. 2 is a perspective view seen diagonally from below. The insulating substrate 1 is made of ceramic or the like. Three through holes 2 are bored in a straight line at equal intervals in this insulating substrate 1. Further, the insulating substrate 1 is provided with three through holes 5 and three notches 6 for supporting the three pairs of conductive support members 3 and 4. Adhesive glass for adhesively fixing the insulating substrate 1 and the conductive support members 3 and 4 after passing through or fitting the conductive support members 3 and 4 is stored in the inner shoulder of the insertion hole 5 and the notch 6. A stepped portion is formed. Furthermore, an X-shaped groove 7 of a predetermined depth is bored on the upper surface of the insulating substrate 1 between the three sets of cathodes. Furthermore, as is clear from FIG. 2, slits 8 are formed in the lower surface of the insulating substrate 1 between the respective through holes 2, and a recess for inserting adhesive glass is formed near the center of the slit 8. There is. A support 10 made of a single plate and having notches 9 at both ends is fitted into each slit 8 and fixed thereto. The vicinity of the notch 9 of this support body 10 is fused to the insulating support rod of the electron gun to support the insulating substrate 1. One support member 3 of the pair of conductive support members 3 and 4, which are arranged at a predetermined distance from each other so as to penetrate through the insulating substrate 1 as described above, is connected to the base metal plate 11 and the electronic support member 3. One end of a filament 13 with a radioactive material 12 placed in its center is fixedly supported, and the other support member 4 supports the other end of the filament 13 in such a way that one end extends outside of the support member 4. By being fixed to a spring member 14 fixed to this support member 4, it is supported so as to have elastic force. In addition, the support member 4 is formed into a rectangular hollow body that serves as a guide for a movable adjustment rod 15 that comes into contact with the filament 13 and adjusts its height in order to maintain a predetermined distance between the support member 4 and the first grid electrode. ing. The support member 3 on the side to which the filament 13 is fixed is connected to the insertion hole 5 of the insulating substrate 1.
a spring member 14 that penetrates through and is adhesively fixed, and also adjusts the relationship between the first grid electrode and the electron emitting material 12;
and a movable side support member 4 equipped with a movable adjustment rod 15.
is fitted into the notch 6 of the insulating substrate 1 and fixed with adhesive. A filament 1 is attached to this movable support member 4.
A spring member 14 attached to fixedly support one end of the filament 13 absorbs the elongation due to thermal expansion of the filament 13 or provides an elastic force so that the position of the filament 13 can be moved up and down. or,
The electron emitting material 12 is made by coating (Ba, Sr, Ca) Co ₃ on the upper surface of the base metal plate 11 formed of a Ni-based alloy containing Mg, Si, W, etc. Further, as described above, the movable adjustment rod 15 is used for adjusting the distance between the first grid electrode and the electron emitting material 12 to a predetermined distance, and the movable adjustment rod 15 is used to adjust the distance between the first grid electrode and the electron emitting material 12 to a predetermined distance. After the electron emitting material 12 is embedded in and assembled together, it is inserted into the movable support member 4 to adjust the placement position of the electron emitting material 12, and is moved up and down along the movable support member 4. It is something that makes you

Next, a method for manufacturing the directly heated composite cathode assembly as described above will be described. First, the stationary support member 3 is inserted into three sets of insertion holes 5 previously provided in the insulating substrate 1, and glass powder as an adhesive is applied and heated to melt and fix. In this case, there is no problem even if glass that has been pre-pressed into an annular shape is fitted and heated. On the other hand, the support member 4 on the movable side is also inserted into the notch 6 and fixed to the insulating substrate 1 by heating and melting it with glass powder in the same manner as above. In this way, three sets of both supporting members 3, 4
After fixing, as shown in FIG. 3, both supporting members 3 and 4 are pressure-molded from above to set the height from the reference plane, that is, the insulating substrate 1, to a predetermined dimension. At this time, the height of each support member 3, 4 is higher than that of support member 3 because the filament 13 is stretched nonparallelly.
Set it 0.05 to 0.1mm lower. Further, the dimensions of both the supporting members 3 and 4 are made large in consideration of the pressure dimension. Furthermore, a problem with the above-mentioned pressure forming is the absorption of pressure stress, but in a linear structure, force is applied directly to the glass fixing part, making it unusable. Therefore, in the present invention, as is clear from FIGS. 1 and 3, each support member is provided with a bending portion for absorbing pressure stress in advance. That is, the fixed support member 3 is provided with a curved portion 3a, and the other support member 4 is provided with a flared bent portion at its tip. Then, each bent portion is plastically deformed by applying pressure in the axial direction.

After setting the height dimensions of the support members 3 and 4 by pressure molding in this way, the filament 1 is attached to the fixed side support member 3 and the spring material 14 as shown in FIG.
3. Next, the base metal plate 11 is fixed approximately at the center of the filament 13, and the electron emitting material 12 is applied onto the base metal plate 11. In this way, a directly heated composite cathode assembly including three sets of parallel filaments 13 of the same height is completed. In this directly heated composite cathode structure, the height of the filament 13 is further adjusted by the movable adjustment rod 15 when assembling the electron gun, and the distance between the first grid electrode and the electron emitting material 12 is set to a predetermined dimension. In addition, 16 and 17 in the figure are adhesives.

The method for manufacturing a directly heated composite cathode structure of the present invention is configured as described above and shown in the drawings, and after fixing the fixed side support member 3 to the insulating substrate 1, pressure molding is performed to form the fixed side supporting member 3 from the reference plane, that is, the surface of the insulating substrate 1. Since the dimensions are set, the height dimensions of the three sets of support members 3 do not vary to the extent that they cause a problem. Therefore, in an in-line three-electron gun using a directly heated composite cathode structure manufactured by the manufacturing method of the present invention, the distances between the first grid electrode and the surface of the electron emitting material 12 are the same in the three sets of electron guns, As a result, the characteristics of the cathode potential and anode current, which are the basic characteristics of an electron gun, are matched, resulting in very good image quality.

As explained above, according to the present invention, it is possible to provide a method for manufacturing a directly heated composite cathode assembly with great practical value.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a directly heated composite cathode assembly manufactured by the manufacturing method of the present invention, seen from diagonally above, FIG. 2 is a perspective view of the same as seen from diagonally from below, and FIGS. FIG. 2 is a cross-sectional view showing a method of manufacturing a directly heated composite cathode assembly according to an embodiment of the present invention. 1...Insulating substrate, 3, 4...Supporting member, 3a...
...Curved portion, 11...Base metal plate, 12...Electron emitting material, 13...Filament, 14...Spring member, 15...Movable adjustment rod.

Claims (1)

[Claims] 1. An insulating substrate fitted into a first lattice electrode in the form of a covered cylinder, and three pairs of conductive support members that are implanted through the insulating substrate at predetermined intervals;
A filament stretched between each pair of support members, a base metal plate and an electron emitting material fixed approximately at the center of the filament, and a material provided on one of the pair of conductive support members to emit electrons. In the method for manufacturing a directly heated composite cathode assembly comprising adjustment means for adjusting the position of a substance, each support member is provided with a bending portion for absorbing pressure stress in advance and fixed to the insulating substrate, and then the support member is fixed to the insulating substrate. Each support member is pressurized in the axial direction to plastically deform each bent portion to set the height from the surface of the insulating substrate to the tip to a predetermined dimension, and then the filament is stretched between the support members. A method for manufacturing a directly heated composite cathode structure.