JPS6252415B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of manufacturing a cathode holding part for an electron tube suitable for use in an electron gun of a color picture tube. Generally, a cathode ray tube electron gun is provided with a cathode that is heated to emit electrons. This cathode is housed inside a cylindrical cathode mounting part,
This cathode mounting portion is further fixed within the envelope. The cathode is then assembled by fixing this envelope to an electrode support made of beet glass. However, such conventional cathode devices, such as cathode ray tubes for color televisions, have problems in that three sets of cathode mounting portions and envelopes are used, resulting in a large size and requiring a large number of assembly steps. For this reason, a cathode holding component having a structure in which the envelope is unified into one is being considered. FIG. 1 is a partially sectional front view of a cathode holding part of an in-line electron gun in which such an envelope is shared, and FIG. 2 is a plan view. In the figure, 1 is an envelope, 2 is three cylindrical cathode mounting parts arranged horizontally in the envelope 1, and 3 is a cathode mounting part 2 that is insulated and held inside the envelope 1. It is a crystallized glass for These envelope 1, cathode mounting portion 2, and crystallized glass 3 constitute a cathode holding component. Although not shown, a heater and a cathode are housed in the cathode mounting portion 2, and the envelope 1 is fixed to an electrode support. Although it is possible to use ceramic instead of crystallized glass 3, crystallized glass is generally used because it is cheaper and easier to manufacture. When manufacturing such cathode holding parts,
A firing jig is used to position the envelope and the cathode mounting part, but if this firing jig is made of metal, crystal glass will adhere to it during firing, making it impossible to remove the cathode holding part from the firing jig. Therefore, those made of carbon, which does not have glass attached and is heat resistant, are usually used. Firing jigs made of carbon like this do not have crystallized glass attached to them, are heat resistant, and are inexpensive, making them excellent jigs. However, during firing, the carbon turns into crystallized glass. I had a problem with it sticking. If carbon adheres to the cathode holding parts, it impairs the insulation, and if it falls off after being assembled into the electron tube, it can cause a fatal defect. For this reason, it is necessary to remove the adhering carbon from the cathode holding parts after firing, but since the carbon has been heat treated, it is firmly attached to the crystallized glass, making it difficult to completely remove it with normal surface treatments. It is. As methods for removing adhered carbon, there are known methods such as mechanically polishing the surface, consuming carbon by heat treatment, and cleaning. First, as a method for mechanically polishing the surface, there is a sandblasting method, but it is difficult to put into practical use because it causes cracks in the crystallized glass and deforms the cathode mounting part. Next, as a heat treatment method, heating in air to burn and consume carbon is considered, but since the softening point of crystallized glass is relatively low, high temperature treatment is not possible and complete removal is difficult. There was a problem that the metal parts of the envelope and cathode mounting part were oxidized and weakened. The next cleaning method is to use acid or alkali to clean it, but this method cannot be used because crystallized glass is sensitive to acids and alkalis due to its material nature, and high-temperature reduction with hydrogen is also restricted. Practical implementation was difficult. As described above, no matter what method is used in the past, it has not been possible to completely remove carbon attached to crystallized glass. The present invention was made to eliminate such conventional drawbacks, and its purpose is to completely remove carbon attached to crystallized glass without affecting other parts. An object of the present invention is to provide a method for manufacturing a tube cathode holding component. In order to achieve such an objective, the present invention
After firing, ultrasonic cleaning is performed in an aqueous solution containing an abrasive and a surfactant. Hereinafter, the present invention will be explained in detail with reference to Examples. FIG. 3 is a partially enlarged view of a cleaning step in an embodiment of the method for manufacturing a cathode holding component for an electron tube according to the present invention. After attaching the envelope and the three cathode mounting parts to a firing jig made of carbon and positioning them relative to each other, a
Filled with crystallized glass powder consisting of 165 parts by weight of ZnO, 25 parts by weight of B ₂ O ₃ , 10 parts by weight of SiO ₂ with addition of Al ₂ O ₃ , and fired by heating to approximately 850°C in a nitrogen atmosphere. . By this firing, the crystallized glass is melted, and the envelope and the cathode mounting portion are integrated through the crystallized glass. After firing, this integrated cathode holding component is removed from the firing jig. The shape at this time is exactly the same as in FIGS. 1 and 2.
Next, the cathode holding part is placed in a cleaning liquid in which an abrasive made of Si-based fine particle powder is dispersed in an aqueous solution of a surfactant made of alkylbenzenesulfonic acid, and ultrasonic vibrations of 20 to 40 KHz are applied to the cleaning liquid. Perform ultrasonic cleaning. FIG. 3 shows this state, and in the figure, 3 is crystallized glass, 4 is carbon attached to the surface of crystallized glass 3, 5 is an aqueous surfactant solution, and 6 is an abrasive. When cleaning in this way, the abrasive material 6 is cleaned by ultrasonic energy.
vibrates, and this vibration energy causes carbon 4
is peeled off from the surface of the crystallized glass 3 and liberated into the surfactant aqueous solution 5. The liberated carbon 4 is surrounded by the surfactant and is no longer attached to the crystallized glass 3. Here, the results of an experiment conducted by changing the particle size (diameter) of the abrasive material 6 are shown in the following table.

[Table] The judgment of the results is as follows. ○: Carbon is completely removed. Δ: Carbon peeling effect is present, but there are some imperfections. ×: There is almost no carbon peeling effect. In this way, if the particle size of the abrasive is smaller than 0.05 μm, sufficient vibration energy cannot be absorbed and it is difficult to obtain a peeling effect, and if the particle size is larger than 20 μm, the abrasive tends to settle in the aqueous solution and has no chance of coming into contact with carbon. was so small that almost no effect could be obtained. Therefore, in this example, the optimum particle size of the abrasive is
It was 0.1 to 10 μm. Note that this cleaning did not cause any damage to the crystallized glass or the cathode mounting portion. In addition, the concentration of the surfactant aqueous solution is expressed as a weight ratio.
There was no effect at less than 0.1%, and a sufficient effect was obtained at 0.5% or more. Furthermore, the concentration of the abrasive in the aqueous surfactant solution may be within a range that allows it to move freely with ultrasonic energy, but as a result of experiments, it has been found that
0.5-2.0% was optimal. When the concentration is lower than this range, there is no effect, and when the concentration is higher than this range, the movement of the abrasive is restricted and a sufficient effect cannot be obtained. The cathode holding parts cleaned in this way were further washed with water to remove the cleaning liquid, dried, and assembled together with other parts into a cathode ray tube. As a result, a high-quality product was obtained. In the above examples, alkylbenzenesulfonic acid was used as the surfactant and Si-based fine particle powder was used as the abrasive, but various other surfactants can be used, and as the abrasive, for example,
Various materials such as Ca-based fine particle powder can be applied. As described above, according to the method of manufacturing a cathode holding part for an electron tube according to the present invention, carbon attached to crystallized glass can be completely removed without affecting other parts, and the characteristics of the electron tube can be improved. There is.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional front view of a common cathode holding component, FIG. 2 is a plan view thereof, and FIG. 3 is an enlarged partial view of a cleaning step in an embodiment of the method for manufacturing a cathode holding component for an electron tube according to the present invention. It is a diagram. DESCRIPTION OF SYMBOLS 1... Envelope, 2... Cathode attachment part, 3... Crystallized glass, 4... Carbon, 5... Surfactant aqueous solution,
6...Abrasive.

Claims (1)

[Scope of Claims] 1. After attaching a cathode mounting part and an envelope to a baking jig made of carbon, and packing crystallized glass powder between the cathode mounting part and the envelope, approximately
A cathode holding part for an electron tube, characterized in that the parts are fired at 850°C to integrate them, removed from the firing jig, and then subjected to ultrasonic cleaning in an aqueous solution containing an abrasive and a surfactant. manufacturing method. 2. The method of manufacturing a cathode holding part for an electron tube according to claim 1, wherein the abrasive has a particle size of 0.1 to 1.0 μm.