JPH09161680A - Manufacture of cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the unnecessary residual gas inside a tube, and to lower the change of the electron emitting characteristic with elapse of time so as to prolong the lifetime by supplying dry air, nitrogen or inert gas for substitution after the frit baking, sealing a neck part with a closure. SOLUTION: Organic material such as polyvinyl alcohol in a fluorescent film slurry, which is formed in the inner surface of a panel part 3, and such as lacquer in the filming is burned for thermal decomposition. A valve is heated at a high temperature so as to weld a panel part 3 and a funnel part 2 to each other through a frit glass layer 7. In the next valve cooling process, dry air, nitrogen and the inert gas at the nearly same temperature with the temperature of the valve part are supplied from a neck part 1 through a gas lead-in pipe 8, and these gas is substituted for the material inside of the tube, and the neck part 1 is sealed by a closure 9. In the next process, an electron gun is installed in the neck part 1, and thereafter, inside of the valve is vacuumed. Steam and decomposed gas to be adhered to the tube wall is thereby lowered, and furthermore, contamination of the unnecessary gas during the movement to the next process can be prevented.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a color cathode ray tube.

[0002]

2. Description of the Related Art A method for manufacturing a cathode ray tube is generally shown in FIG.
The manufacturing steps shown in FIG. First, in the fluorescent film / aluminum film forming step 101, the surrounding portion of the cathode ray tube (hereinafter,
A fluorescent film and an aluminum vapor-deposited film are formed on the inner surface of the panel portion that constitutes the bulb). In this case, for the purpose of forming an aluminum vapor-deposited film that is as smooth as possible, film formation of an organic suspension is performed after forming the fluorescent film. Next, the valve is placed in a heating furnace and a heat treatment process 102 is performed. First, a panel baking step 21 is carried out to heat and decompose organic substances such as polyvinyl alcohol in the fluorescent film slurry formed on the inner surface of the panel portion and lacquer in filming by heating, and then heating the bulb to a high temperature. Then, a frit baking step 22 of welding and joining both the panel portion and the funnel portion with frit glass is performed. After that, a stem sealing step 23 of mounting an electron gun on the neck portion and sealing the same, and a vacuum exhaust step 24 of evacuating the inside of the valve are sequentially performed. Heat treatment step 2 here
In Nos. 1 and 22, when each process is independently performed, the temperature of the valve is repeatedly raised and lowered, the process time is increased as a whole, the energy consumption is increased, and the manufacturing cost is increased. Has also been proposed (Japanese Patent Laid-Open No. 2-793
No. 23). Then, the aging process 103 and the reinforcing process 104 are performed to complete the process.

By the way, in the heat treatment step, many unnecessary gases (decomposition gas and moisture) are released into the pipe by heating the valve. This unnecessary gas is difficult to be discharged to the outside of the tube, is re-adsorbed on the inner surface of the bulb, and remains in the subsequent steps, resulting in a problem that the life characteristics of the cathode ray tube are significantly deteriorated.

Therefore, after the completion of the frit baking step 22, as soon as possible, before the temperature of each part is lowered to normal temperature,
It has been proposed to install a vacuum exhaust process for exhausting the gas released in the tube (Japanese Patent Laid-Open No. 2-75129).

[0005]

If unnecessary gas (decomposition gas or moisture) is adsorbed and remains inside the cathode ray tube at the time of completion, the cathode ray tube may be damaged by temperature rise in the tube or electron impact during operation. It was discharged and became a factor that deteriorates the electron emission characteristics of the cathode. In other words, in order to extend the life of the cathode ray tube, it is necessary to reduce the unnecessary gas released into the tube during operation, and it is necessary to reduce the unnecessary gas that is re-adsorbed and remains on the tube wall during the manufacturing process. is there.

In the heat treatment step 2, unnecessary gas is released into the valve. Almost all of these unnecessary gases are carried away by being mixed with the atmosphere because the valves are open during the panel baking process 21. However, after the frit baking step 22, both the panel portion and the funnel portion are welded and joined with the frit glass, so that the opening portion to the atmosphere is only the neck portion. However, since the neck portion is very thin, the gas released in the tube is not easily released into the atmosphere from the tube, and some of the gas remains in the tube. The water vapor, which accounts for a small proportion of the released gas, is adsorbed everywhere in the tube when the tube wall is cooled down to room temperature, and a part of it is taken in as crystal water. It is difficult to completely drain all the water.

For this reason, it has been considered to install a vacuum evacuation step for exhausting the unnecessary gas released into the tube to the outside of the tube after the frit baking step 22 is completed. As a result, the unnecessary gas in the pipe is removed at one end, and the valve moves to the stem sealing step 23 which is the subsequent step.

However, while the valve is moving to the stem sealing step 23, unnecessary gases (mainly water, carbon dioxide, etc.) in the atmosphere enter the pipe through the neck portion which is the opening portion of the valve, and eventually, It re-adsorbs in the tube. Although these unnecessary gases are removed to some extent in the vacuum evacuation step 24, carbon dioxide and carbon monoxide are released at a high temperature of about 400 ° C. Therefore, if the maximum heating temperature in the vacuum evacuation step 24 is lower than this temperature, There is a high possibility that they will remain in.

[0009]

In order to solve the above problems, in the frit baking process 22 in the cathode ray tube manufacturing process, heating is completed, and during the cooling process of the valve, the thin tube is inserted from the neck portion and the dry air is introduced. Alternatively, replacement is performed by supplying dry nitrogen or dry inert gas. Further, plug the neck part.

As a result, it is released into the tube by heating,
The residual unnecessary gas is forced out and the inside of the valve is replaced with the gas. Further, by plugging the neck portion, gas in the atmosphere is prevented from entering the tube. That is,
The unnecessary gas that is re-adsorbed in the pipe as the valve cools to room temperature is reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A cathode ray tube manufacturing process for explaining an embodiment of the present invention is shown in FIG. The fluorescent film 4 is formed in the conventional manner. That is, in the fluorescent film / aluminum film forming step 1, the fluorescent film is formed on the inner surface of the panel portion forming a part of the color cathode ray tube, and then the aluminum vapor deposition film 4 is formed on the fluorescent film. In this case, for the purpose of forming an aluminum vapor-deposited film that is as smooth as possible, film formation of an organic suspension is performed after forming the fluorescent film.

Next, after forming the aluminum vapor deposition film, the valve is placed in a heating furnace and a heat treatment step 2 is performed.

In the heat treatment step 2, first, a panel baking step 21 is performed for the purpose of burning and decomposing organic substances such as polyvinyl alcohol in the fluorescent film slurry formed on the inner surface of the panel portion and lacquer in the filming to thermally decompose them. Then, the valve is heated to a high temperature, and a frit baking step 22 of welding and joining both the panel portion and the funnel portion with frit glass is performed. Frit baking process 2
After the end of 2, a gas supply / plug attachment step 23 as shown in FIGS. 3 and 4 is provided. That is, in the process of cooling the valve up to the next step 24, the dry air or dry nitrogen or the dry inert gas corresponding to the temperature of the valve portion is supplied from the neck portion 1 through the gas introduction pipe 8. As a result, the gas released into the pipe is expelled to the outside of the pipe through the gap between the neck portion and the gas introduction pipe 8, and the inside of the pipe is replaced with dry air or the like.
When the inside of the pipe is replaced with dry air or the like, the neck portion 1 is capped with 9. Then, the valve is moved to the next process in this state, and the stem sealing process 24 for mounting the electron gun on the neck portion 1 for sealing and the exhaust process 25 for evacuating the inside of the valve are sequentially performed.

Thereafter, the aging step 3 and the reinforcing step 4 are performed to complete the cathode ray tube.

[0015]

The present invention can reduce water vapor and decomposition gas adsorbed on the tube wall in the cooling process after the completion of the frit baking process. While moving to the next process,
Prevents unwanted gas from entering the pipe into the pipe. As a result, in the exhaust process of the next process, unnecessary gas released into the valve is reduced, and the exhaust of the valve becomes easier. That is, it is possible to reduce unnecessary gas remaining in the tube and obtain a Braun tube having a long life and a small change in electron emission characteristics over time. Also in the projection type cathode ray tube, the same effect can be obtained by providing the gas supply and plug attaching step 23 after the step corresponding to the panel baking step 21 described above.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a manufacturing process of a cathode ray tube.

FIG. 2 is a flowchart showing a manufacturing process of a cathode ray tube according to an embodiment of the present invention.

FIG. 3 is an explanatory view showing a gas supply method to a cathode ray tube showing an embodiment of the present invention.

FIG. 4 is an explanatory view showing a way of plugging the neck portion of the cathode ray tube showing an embodiment of the present invention.

[Explanation of symbols]

1 ... neck part, 2 ... funnel part, 3 ... panel part, 4 ...
Fluorescent film, 5 ... Shadow mask, 6 ... Interior graphite, 7 ... Frit glass layer, 8 ... Gas introduction tube, 9 ... Plug, 10 ... Handle.

Claims (1)

[Claims] 1. A method for manufacturing a cathode ray tube comprising a frit baking step of welding and joining a panel section and a funnel section with frit glass in a heating furnace, and a stem sealing step of supporting an electron gun, wherein the frit baking step is completed. A method for producing a Braun tube, characterized in that post-dry air, nitrogen or an inert gas is supplied into the Braun tube to replace the inside of the Braun tube with the gas and the neck portion is plugged.