JPH0221534A - Manufacture of indirectly-heated cathode composition - Google Patents

Abstract

PURPOSE:To make it possible to set the interval between the top of a heater and a cathode base body accurately at a desired value by removing minute particles to the outside after forming a flat minute particle layer on the inner surface of the cathode base body and fixing the heater to a heater holding member at the position the top of the heater is contacted to the surface of the minute particle layer. CONSTITUTION:Minute particles necessary to separate the interval between the top of a heater 3 to be inserted and a cathode base body 2 at a desired distance are put in from the opening of a cathode sleeve 4 by using a hopper, and a flat minute particle layer 21 is formed on the cathode base body 2. Then, the heater 3 whose legs are fixed to a tube 12 combined with a joint 22 is inserted quietly from the opening of the cathode sleeve 4, the tube 12 is welded to a connecting piece 13 at the position the top of the heater 3 is contacted to the surface of the minute particle layer 21, and the joint is cut off. Furthermore, an electron gun composition is removed from a holder, and the minute particles are removed to the outside while placing the opening of the cathode sleeve 4 in the lower side. In such a way, the interval between the top of the heater 3 and the cathode base body 2 can be set highly accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing an indirectly heated cathode assembly, and more particularly to a method for spacing a heater from a cathode substrate.

[Conventional technology]

A cathode ray tube, for example a color cathode ray tube, usually uses an electron gun having an indirectly heated cathode structure, and this type of cathode structure has an electron emitting material layer 1 on the outer surface, for example, as shown in FIG. It is composed of a cup-shaped cathode base 2 having a diameter, a cylindrical cathode sleeve 4 housing a heater 3, a disk 5 holding the heater 3, and an eyelet 6 holding the disk 58. This cathode structure 7 is connected to an insulating support 9I via a support member 8 joined to the eyelet 6.
Tightly fixed and held.

The heater 3 is formed by forming a core wire 10 into a coil shape, which is coated with an insulating coating 11, usually alumina, and is inserted in the vicinity where the top reaches the circular surface of the cathode base 2. One end of the core wire 10 is joined to a tab 12, which is welded and fixed to a joining piece 13 provided on the insulating support 9.

By the way, the heater 3 installed as described above expands due to heat during operation, and its top may press the cathode base 2 and deform it, causing a change in the distance between the top surface of the cathode and the grid 15. , there arises the disadvantage that the electrical characteristics of the electron gun, especially the cut-off characteristics, are changed. Furthermore, when the top of the heater 3 presses against the cathode base 2 in this manner, there is a possibility that cracks will occur in the insulation coating 11 of the heater 3, degrading the insulation properties of the heater.

For this reason, by providing a distance 1 between the top of the heater 3 and the cathode base 2, for example, about 0.2, even if the heater 3 expands due to heat during operation, the top of the heater 3 is connected to the cathode base 2. I try not to press 2.

In FIG. 4, a tab 16 that locks the heater 3 is bent at right angles to form a locking piece 17 of a certain thickness, and this is applied to the lower end of the joint piece 13 that has been set at a predetermined position. By contacting and joining, the top of the heater 3 and the cathode base 2
This is a method of regulating the distance between
It is disclosed in Publication No. 0.

In FIG. 5, a spacer 18 made of a material that decomposes and evaporates when heated is provided on the top of the heater 3, and this is inserted into the cathode sleeve 4. This spacer 18 connects the top of the heater 3 and the cathode base 2. After regulating the interval and joining the tab 12 of the heater 3 to the joining piece 13, the spacer 18 is heated to decompose and evaporate it to remove it,
Japanese Unexamined Patent Publication No. 55-37788 discloses a pot.

[Problem to be solved by the invention]

However, a locking piece 17 is provided on the tab 16 in FIG.
There is a method of regulating the distance between the heater 3 and the cathode base 2 by bringing this into contact with the lower end of the joint piece 13. Therefore, there is a tolerance in the dimensional accuracy of each member constituting the cathode structure, and each member is Because it is difficult to set the exact position,
It is difficult to stably secure the above-mentioned distance, and the work requires skill, which may increase the manufacturing cost of the tortoise.

In addition, according to a method in which a spacer 18 formed of a component that decomposes and evaporates when heated is provided on the top m of the heater 3, and this spacer 18i regulates the distance between the heater 3 and the cathode base 2, Organic substances such as acrylic resin and polyvinyl alcohol are used as materials to be evaporated, so even if they are heated, decomposed, and evaporated, a residue remains, which may cause abnormal discharge during operation, or cause the electron emitting material layer to evaporate. The use of such a spacer 18 is not very preferable because there is a risk that it may adhere to or be adsorbed to the surface and deteriorate the electron emission characteristics.

In view of the above-mentioned conventional problems, the object of the invention is to provide an indirect heating type that allows the distance between the top of the heater and the cathode substrate to be accurately set to a desired value, and that does not adversely affect the electron emission characteristics. An object of the present invention is to provide a method for manufacturing a cathode structure.

[Means to solve the problem]

The above object is to provide a method for manufacturing a cathode assembly having at least a cup-shaped cathode base having an electron emitting material layer on the outer surface of the closed end, and a cylindrical cathode sleeve having one end fixed to the open end side of the base. Strain the opening on the other end of the cathode sleeve upward (straighten the opening), put a certain amount of microparticles through this opening, form a flat microparticle layer on the inner surface of the cathode base, and then insert the opening into the pot. After inserting the heater and fixing the heater to the heater holding member at a position where the top of the heater is in contact with the surface of the microparticle layer, the microparticles are removed to the outside, so that the top of the heater and the cathode base are connected to each other. This is achieved by spacing a predetermined distance between them.

[Effect]

By the above means, a microparticle layer is formed with a certain thickness on the inner surface of the cathode substrate from a certain amount of one microparticle,
Due to the thickness of this fine particle layer, the distance between the top of the heater and the cathode base can be regulated with high precision.

〔Example〕

Hereinafter, an embodiment according to the invention will be described in more detail with reference to FIGS. 1 and 2. The same members as those in FIG.

First, as shown in FIG. 1, a cathode assembly 19 without a heater incorporating a cathode sleeve 4 having a radiation material layer 1 is held by a holder (not shown) with its opening facing upward.

Next, microparticles necessary to maintain a desired distance between the top of the heater 3 to be inserted and the cathode base 2 are introduced into the opening of the cathode sleeve 4 using the hopper 20, and are flattened onto the cathode base 2. A fine particle layer 21 is formed. The distance that the upper part should be separated is usually 0.1 dew ± 0.015
The microparticles that meet this requirement are preferably microparticles of about 10 μm or less, such as alumina, acrylic, etc. In order to form these microparticles flat on the cathode substrate, the cathode sleeve 4 is vibrated slightly. It is effective to do so.

Next, as shown in FIG. 2, the heater 3 with the legs of the tab 12, which is connected with the connecting part 22, is gently inserted into the opening of the cathode sleeve 4, and the top of the heater 3 is The tab 12 is welded to the joint piece 13 at the position where it contacts the surface of the fine particle layer 21, and the joint portion 14 is cut off.

Next, although not shown, when the electron gun assembly 18 is removed from the holder and the opening of the cathode sleeve 4 is pulled down to remove the microparticles, the distance between the top of the heater 3 and the cathode base 2 is reduced. Set with high precision. Note that the above-mentioned microparticles may be removed to the outside by vacuum suction.

〔Effect of the invention〕

According to the present invention as described above, the distance between the top of the heater and the inner surface of the cathode substrate can be set at n degrees of about 1/100 square meters, so that stable electron gun characteristics can be obtained and the reliability of the electron gun can be improved. In particular, in a color cathode ray tube, since there is no variation in the electron emission characteristics of each electron gun for each color, particularly in the rise characteristics of electron emission, the deterioration of color purity characteristics at the time of image output is reduced.

In addition, since the above-mentioned constant distance is secured, even if the heater expands thermally during operation, there is no risk of it contacting the card base and causing cracks in the heater's insulation coating, thereby deforming the cathode base. No inconvenience will occur.

Furthermore, the method of the present invention has very little cost, and has good productivity.

[Brief explanation of the drawing]

? ;g1 and 2 are longitudinal cross-sectional views of essential parts of an indirectly heated cathode assembly for explaining a manufacturing method according to an embodiment of the present invention; Figure 2 shows the heater inserted, Figure 3 is a vertical cross-sectional view of the main parts to explain the cathode structure, and Figure 4 explains the conventional manufacturing method of setting the heater position by providing a locking part. FIG. 5 is a longitudinal sectional view of the main part of the cathode for explaining a conventional manufacturing method in which a spacer is provided in a heater and its position is set. 3... Heater, 4... Cathode sleeve, 1
2... Tab, 13... Joining piece, 19... Cathode structure, 20... Hopper 21... Microparticles Figure 1 4: Force 1 node sleeve. 9: Weaving 1 Gold Kyuukitai 20: Sun (・Sono ＼ 0- 21: Imaki) 1, Grain Sea Layer 1st Heataka Tooto Sleeve ゛Tef'' Haze (small scale layer)

Claims (1)

[Claims] 1. Manufacture of a cathode assembly having at least a cup-shaped cathode base having an electron emitting material layer on the outer surface of the closed end, and a cylindrical cathode sleeve having one end fixed to the open end of the base. In the method, with the opening at the other end of the cathode sleeve facing upward, a certain amount of microparticles is introduced through this opening to form a flat microparticle layer on the inner surface of the cathode substrate, and then the above-mentioned After inserting the heater through the opening and fixing the heater to the heater holding member at a position where the top of the heater is in contact with the surface of the microparticle layer, the top of the heater and the cathode are removed by removing the microparticles to the outside. 1. A method for producing an indirectly heated cathode assembly, which comprises separating the cathode assembly and the base body by a predetermined distance. 2. The fine particle layer formed on the cathode substrate has a thickness of approximately 10μ
2. The method for producing an indirectly heated cathode structure according to claim 1, wherein the cathode structure is made of particles having a particle diameter of m or less.