JPH0222497B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for regenerating a shadow mask for a color cathode ray tube, and more particularly to a method for regenerating a shadow mask built into a color cathode ray tube that has undergone getter flushing. .

[Prior art] Generally, when a defective tube occurs during the manufacturing process of a color cathode ray tube, it is uneconomical to discard the entire color cathode ray tube because the materials that make up the color cathode ray tube are relatively expensive, and the main Collect component parts such as panels, funnels and shadow masks,
It is being regenerated.

FIG. 1 shows a cutaway cross-section of essential parts of a color cathode ray tube. The color cathode ray tube 1 includes a panel section 1a having a shadow mask 2 suspended from panel pins on its inner surface, a fluorescent film 3 formed on the inner surface facing the panel section 1a, a network section 1b housing an electron gun 4, and the inner surface thereof. A funnel portion 1c is coated with a conductive duct and has a getter 5 which is supported by the electron gun 4 and protrudes from the funnel portion 1c.

If various troubles occur during the manufacturing process of the color cathode ray tube 1 and a defect occurs in the inspection process after getter flashing, crack the neck 1b of the color cathode ray tube 1 and remove the tube under vacuum. After destroying the panel part 1, use approximately 10% nitric acid.
Part of the frit glass that connects the panel part 1a and the funnel part 1c is melted, and the panel part 1a and the funnel part 1c are separated by a heat cycle using hot and cold water. Then, take out the built-in shadow mask 2, remove the remaining frit glass on the panel section 1a and funnel section 1c, remove the fluorescent film 3 or conductive duct on the inner surface, and replace the new neck section 1b with the funnel section 1c. to finish collecting and playing.

On the other hand, as shown in FIG. 2, the shadow mask 2 has a getter film 6 deposited on its surface, which can be removed by cleaning with a highly concentrated caustic soda solution, cleaning with alcohol, chromium trioxide, etc. Cleaning with various oxidizing agent solutions is carried out, and sometimes scrubbing in the above solutions is also added.

However, both of them are Shadow Mask 2
In addition to altering and damaging the blackened film formed on the surface of the mask, the spherical surface of the mask may be deformed, and since it takes a long time to regenerate, rust may occur during regeneration. As a result, troubles such as blackened film falling off, rusting, and clogging occur frequently during reuse processes, and the regeneration rate is low considering the time required for reuse, making it not a good regeneration method. Ta.

Furthermore, this problem is fatal when regenerating shadow masks with extremely small hole diameters used in high-resolution color cathode ray tubes that are being produced in large numbers recently, resulting in further deterioration of regeneration efficiency.

[Summary of the Invention] This invention has been made to eliminate the above-mentioned conventional drawbacks, and provides a color that can completely remove the getter film without altering or damaging the blackened film, and is free from any risk of rusting. The purpose of the present invention is to provide a method for reproducing a shadow mask for a cathode ray tube.

[Embodiments of the Invention] Examples of the invention will be described below with reference to the drawings.

Separating the defective tube after getter flushing in FIG. 1 into a panel part 1a and a funnel part 1c,
The internal shadow mask 2 is taken out and washed by immersion in an aqueous solution of about 3% succinic acid for 20 to 30 seconds to dissolve and remove the getter film 6 adhering to the surface of the shadow mask 2. Next, after washing with water, each
Wash by immersing in 0.5% ammonia aqueous solution for 5 to 10 seconds and drying in a dryer. The getter film 6 of the shadow mask 2 thus regenerated was completely removed, the blackening film was not altered or damaged in any way, and rusting during the regeneration was completely suppressed. It was confirmed that even when this recycled shadow mask 2 was subjected to the normal manufacturing process of the color cathode ray tube 1, it did not deteriorate or rust in the heat treatment furnace, and there were no problems in terms of characteristics even when it was used as a finished tube.

As another example, after breaking the vacuum of the defective tube after getter flushing and leaving it for several days, the recovered shadow mask 2 with the deteriorated getter film 6 attached thereon is treated with about 2% formic acid aqueous solution from both front and back sides. Ten
Spray cleaning for ~15 seconds, then spray cleaning with water, and then spray cleaning in the same manner with an approximately 1% aqueous morpholine solution and dry. The thus regenerated shadow mask 2 is in good condition as in the above-described embodiment, and dust such as glass powder is removed when the panel portion 1a and the funnel portion 1c are separated, and there is no clogging. was confirmed.

Additionally, in another embodiment, instead of formic acid, about 5
Similar results were obtained when a % oxalic acid aqueous solution was used, and there was no trouble in the post-process due to the residual getter film 6.

Note that the dilute solutions of formic acid, succinic acid, and oxalic acid mentioned here are not limited to aqueous solutions.
Of course, it may be an alcohol solution;
The cleaning method is also not limited to dipping, spraying, ultrasonic cleaning, etc.

Furthermore, it is of course possible to perform a process such as washing with ammonia or morpholine dilute solution, washing again with water or alcohol, and then drying. Needless to say, the present invention can also be applied to cleaning for the purpose of removing clogs.

[Effects of the Invention] As described above, according to the present invention, a dilute solution of formic acid, succinic acid, or oxalic acid completely dissolves and removes the getter film attached to the shadow mask while keeping the blackening film stable. Since the shadow mask is completely neutralized and rust-proofed by a dilute ammonia or morpholine solution, the shadow mask does not rust during or during regeneration, and can be used in the heat treatment furnace that it passes through during the manufacturing process of color cathode ray tubes. Even if the blackened film is repeatedly added, the quality of the blackened film remains unchanged, and the adhesion of the blackened film does not decrease, and a recycled shadow mask that does not have any problems even when used as a finished tube can be efficiently obtained. Sometimes, especially
It is possible to provide a method for reproducing a color cathode ray tube shadow mask that can be applied without any problem to shadow masks with very small hole diameters such as those for high resolution.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway sectional view of a main part of a color cathode ray tube to which the present invention is applied, and FIG. 2 is a front view of a shadow mask recovered from a panel section. 1...Color cathode ray tube, 2...Shadow mask. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. When disassembling and separating a color cathode ray tube to recover its component parts, a step of cleaning the shadow mask built into the color cathode ray tube with a dilute solution of formic acid, saccharic acid, or oxalic acid, and a step of cleaning with water. and a step of cleaning with a dilute solution of either ammonia or morpholine.