JPH0757641A - Cathode-ray tube regenerating method - Google Patents

Abstract

PURPOSE:To regenerate only a nondefective by removing defective panel part and funnel part, and heighten reliability by preventing breakdown in a manufacturing process by applying heat shock having a specific temperature difference to the separated and recovered panel part and funnel part. CONSTITUTION:After frit glass 3 welding a panel part 1 and a funnel part 2 of a defective color cathode-ray tube is melted uniformly over a prescribed range from a bulb side wall by nitric acid of about 40 deg.C, warm water and chilled water having a temperature difference of not less than 30 deg.C is flowed/ poured altenately to/on the whole bulb. A one round crack is created in a frit glass part, and the panel part 1 and the funnel part 2 are separated from each other, and an enclosed shadow mask 5 is taken out. Thereby, even if the obtained panel part is passed again through a manufacturing process of a color cathode-ray tube, breakdown in a heat treatment process is particularly reduced, and pneumatic pressure resistant test after a complete tube is formed does not raise a problem too, so that a highly reliable color cathode-ray tube can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reproducing a cathode ray tube such as a color cathode ray tube, and more particularly to a method for reproducing a defective cathode ray tube in which a panel portion and a funnel portion are welded together via frit glass. Is.

[0002]

2. Description of the Related Art Generally, when a defective tube is produced in the process of manufacturing a color cathode ray tube, it is uneconomical to discard the entire color cathode ray tube because the material cost of the color cathode ray tube is relatively high. The panel part, the funnel part, and the shadow mask, which are the main components, are collected and regenerated.

As shown in FIG. 3, the color cathode ray tube has a panel portion 1 having a shadow mask 5 supported by a frame 4 and a fluorescent film 6 facing the shadow mask, and an electron gun 7 housed in a neck 2a. It is composed of a funnel portion 2 having conductive graphite 8 applied on its inner surface, and the panel portion and the funnel portion are welded with a frit glass 3. Although various problems occur in the manufacturing process of such a color cathode ray tube, if a defective tube is generated after the step of welding the panel portion 1 and the funnel portion 2 with the frit glass 3, it is necessary to add about 10% nitric acid. Then, the frit glass 3 is partially melted, and the panel portion 1 and the funnel portion 2 are separated by a heat cycle of hot water and cold water, and the built-in shadow mask 5 is taken out. Then, the remaining frit glass of the panel portion 1 and the funnel portion 2 is dissolved and removed with the same nitric acid, and each component is washed to remove the fluorescent film 6 and the conductive graphite 8.
Replace the neck tube with a new one. On the other hand, with respect to the shadow mask 5, the getter film is removed by the method described in Japanese Patent Publication No. 22497/1990, and the recovery and reproduction is completed.

[0004]

However, the panel portion and the funnel portion recovered and regenerated by the above-mentioned method have various glass defects caused not only in the manufacturing process of the color cathode ray tube but also in the regenerating process after becoming a defective tube. have. For this reason, defects are inspected with the naked eye at the end of recovery and recovery, and defects that can be recycled are removed by felt buffing or whetstone polishing. The defect cannot be completely removed, and the manufacturing process of the color cathode ray tube at the time of reuse,
In particular, a large amount of glass breakage occurs in the heat treatment process, and sometimes the reliability is impaired when a finished tube is formed.

The present invention has been made in order to solve the above-mentioned conventional drawbacks, and prevents the reproduced panel portion and the funnel portion from being destroyed in the manufacturing process of the color cathode ray tube, and does not impair the reliability of the finished tube. It is an object of the present invention to provide a method for reproducing a cathode ray tube such as a color cathode ray tube.

[0006]

In the method of reproducing a cathode ray tube according to the present invention, a part of frit glass which welds a panel portion and a funnel portion is melted, and the panel portion and the funnel portion are heat cycled. After dismantling into
A heat shock having a temperature difference ΔT of 30 ° C. or more is applied to at least one of the panel portion and the funnel portion that are separated and collected.

[0007]

According to the present invention, a heat shock is applied to the separated panel portion and the funnel portion to destroy the panel portion and the funnel portion having fine glass defects, and the defective panel portion and the funnel portion are destroyed. Since it can be removed and only non-defective products can be reused, destruction in the manufacturing process of the cathode ray tube can be prevented, and the reliability of the finished tube can be improved.

[0008]

【Example】

Was uniformly dissolved in the range of 1.0~2.0mm from the valve side wall in Example _1, poor color cathode ray tube panel portion 1 and the funnel portion 2 frit glass 3 is welded about 40 ° C.-10% nitric acid After that, hot water of about 45 ° C. and cold water of about 10 ° C. are alternately flowed over the entire valve to generate a crack around the frit glass portion to separate the panel portion and the funnel portion, and the built-in shadow mask 5 is removed. Take it out. Then, FIG.
As shown in the processing flow of step 1, the remaining frit glass in the panel part and the funnel part is dissolved and removed with the nitric acid,
For the funnel, remove the inner and outer graphite with approximately 5% hydrofluoric acid and replace the neck tube. For the rest of the panel, hot water of 50 ° C is poured on the inner and outer surfaces for 3 minutes, and immediately after that, cold water of 10 ° C is poured from the outer surface of the panel to apply an instant heat shock, and the outer surface of the panel is sealed. Destruction is generated from the glass defect portion on the surface or the like to remove the defect portion, and the fluorescent film 6 is removed by washing with about 2% hydrofluoric acid on the panel portion where the destruction is not generated. The panel obtained in this way has extremely less damage even during the manufacturing process of the color cathode ray tube, especially in the heat treatment step, and a reliable pressure-resistant color cathode ray tube can be obtained without any problem in the pressure resistance test after the completed tube. I was able to.

Example 2. In addition, regarding another embodiment, FIG.
Will be described. First, the panel portion 1 and the funnel portion 2 are separated, the remaining frit glass is dissolved and removed with the nitric acid, and the inner surface is washed with about 2% hydrofluoric acid to remove the fluorescent film 6. Conduct an inspection. Then, the detected glass defect is subjected to buffing with a felt buff containing cerium oxide or # 240 grindstone polishing to remove the defect and set the panel portion 1 on the transport roller 32. 55 ° C warm water 33
Immediately after pouring on the inner and outer surfaces of the panel section 1 for 4 minutes,
Heat shock is applied by pouring cold water 34 at 0 ° C. from the outer surface of the panel unit 1. Reference numeral 35 is a partition plate for partitioning hot and cold water. This heat shock causes breakage from the glass defect portion that could not be identified by visual inspection. It was confirmed that the panel portion 1 that was not destroyed in this manner had extremely less destruction during the process of manufacturing the color cathode ray tube again. The actual results for the 25-inch TV panel are as follows. A) Destruction rate after re-input of heat shock: 0.3 to 0.5% b) Destruction rate after re-input of heat shock: 2.5 to 6.0% In the example, since the defective portion which could be identified in advance was repaired by polishing or the like, the damage due to heat shock was small, and it was possible to prevent the rate of non-defective recycled materials from being greatly impaired.

Embodiment 3. As yet another embodiment, the panel section 1 and the funnel section 2 which have completed the neck joint and the inspection / polishing rework are set at about 70 ° C. in a heating furnace.
Immediately after heating for 0 minutes, cold air at about 10 ° C. is blown onto the entire outer surface of the outer surface to cause destruction from minute defects that could not be found in the inspection, and the same effects as those of the first and second embodiments can be obtained. It turned out to be.

[0011]

As described above, according to the method of regenerating a cathode ray tube of the present invention, a heat shock having a temperature difference ΔT of 30 ° C. or more is applied to at least one of the separated panel portion or funnel portion. Therefore, it is possible to easily find a glass defect which is difficult to identify by visual inspection in advance, and it is possible to obtain a highly reliable cathode ray tube which is less likely to be destroyed when the cathode ray tube manufacturing process is again introduced.

[Brief description of drawings]

FIG. 1 is a flow chart showing processing steps in a first embodiment of the present invention.

FIG. 2 is a schematic view showing processing steps in a second embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view showing an example of a general color cathode ray tube.

[Explanation of symbols]

 1 ... Panel part 2 ... Funnel part 2a ... Neck 3 ... Frit glass 4 ... Frame 5 ... Shadow mask 6 ... Fluorescent film 7 ... Electron gun 8 ... Conductivity Graphite 31 .. Spray nozzle 32 .. Conveyor roller 33 .. Hot water 34 .. Cold water 35 .. Partition plate

Claims (4)

[Claims] 1. A part of the frit glass that welds the panel portion and the funnel portion is melted, and the panel portion and the funnel portion are separated and disassembled by a heat cycle,
A method of regenerating a cathode ray tube, characterized in that a heat shock having a temperature difference ΔT of 30 ° C. or more is applied to at least one of the panel portion and the funnel portion that have been separated and recovered. 2. The method of regenerating a cathode ray tube according to claim 1, wherein heat shock is applied by pouring cold water after pouring hot water to the separated panel portion or funnel portion. 3. The cathode ray according to claim 1, wherein the separated panel portion or funnel portion is subjected to a heat shock after the glass defects found by a visual inspection are repaired by polishing or the like. How to regenerate a tube. 4. The heat shock is applied by heating the separated or recovered panel portion or funnel portion in a heating furnace and then blowing cold air.
A method for regenerating the described cathode ray tube.