JPS6055946B2 - Cathode ray tube manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a cathode ray tube, and particularly to a heat treatment process for a color picture tube.

Generally, a color picture tube is composed of a glass envelope consisting of a panel part, a funnel part, and a neck part, and the inside thereof is evacuated to a high vacuum.

The inner surface of the face plate of the panel section is coated with a diode that emits red, blue, green, etc. colors that are regularly arranged in dots or stripes. A color selection electrode with a beam passage hole is arranged. Furthermore, an electron gun that emits multiple electron beams is placed in the neck portion. A color picture tube having such a structure has three heating steps of about 400° C. during the manufacturing process. The panel baking process is used to thermally decompose and remove organic materials such as polyvinyl alcohol contained in the silicone slurry applied to the inner surface of the face plate of the panel and acrylic polymer contained in the film that serves as the base for the metal back. It is done.

The frit baking process is performed after the panel baking process by pouring solder glass (frit glass) onto the sealing surface to align the sealing surfaces of the panel part and the funnel part and heat and fuse them.

After the frit baking process, the exhaust process goes through a sealing process where an electron gun is attached to the neck, and then a panel baking process.
This is done to decompose and remove organic materials that were not separated in the frit baking process and remained in the panel and funnel parts while heating and evacuating the inside of the tube to create a high vacuum. Conventionally, each of these processes requires a furnace for each process, and the temperature of the parts is repeatedly raised and lowered each time, which increases the working time and consumes a large amount of thermal energy, which causes an increase in manufacturing costs. was.

To solve this problem, a method has been proposed in which the heating process, that is, the panel baking process to the exhaust process are performed consistently in the same furnace, thereby significantly reducing the number of times the temperature of the parts is raised and lowered compared to the conventional method. . According to this method, the sealing surface of the panel section faces downward, and the sealing surface of the funnel section, which has solder glass attached, faces downward, and a predetermined gap is maintained between the two sealing surfaces, and the air in the furnace is allowed to pass through this gap. The organic material adhering to the inner surface of the panel is thermally decomposed. After this step, the sealing surfaces of the panel part and the funnel part are brought into contact with each other via solder glass to fuse them together, and then the air is evacuated. On the other hand, the electron gun is simultaneously fused to the neck portion of the funnel portion using solder glass when the panel portion and funnel portion are fused together, or is sealed to the neck portion in advance before this step. For this reason, during the step of thermally decomposing the organic material adhering to the panel part, since the electron gun is attached to the neck part of the funnel part, the reducing gas resulting from this thermal decomposition comes into contact with the electron gun and reacts with it.

The cathode of the electron gun is formed with carbonate, which is the base material for the oxide cathode that improves electron emission characteristics.When the reducing gas comes into contact with this carbonate, the electron gun itself heats up to a high temperature in this state. carbonate is reduced. Electron guns that reacted in this way had the disadvantage of poor electron emission characteristics. The present invention was conceived to improve the above-mentioned drawbacks, and its purpose is to provide a method for manufacturing an organic material that reduces manufacturing costs and does not deteriorate the electron emission characteristics of an electron gun. That's true. In order to achieve this object, the present invention allows gas to flow into the panel part from a valve exhaust pipe connected to an electron gun disposed at the neck part of the funnel part before fusing the panel part and the funnel part. It is designed to flow out from the seal surface gap of the funnel part.

The following is a detailed explanation of the present invention. I will explain. FIG. 1 shows an embodiment of the method for manufacturing a cathode ray tube according to the present invention, and shows a front view of a color picture tube during manufacture.

In the figure, a panel portion 1 having a fluorescent surface formed on the inner surface of its face plate is supported by a panel holder 3 with its transparent surface 2 at its peripheral edge facing downward. This panel holder 3 is configured to move up and down by a mechanism not shown. The funnel-shaped funnel part 4 is supported by a valve holder 6 with a sealing surface 5 at its peripheral end facing upward so as to face the sealing surface 2 of the panel part 1. A solder glass 7 is placed on the sealing surface 5 of the funnel portion 4, and the gap between the sealing surfaces 2 and 5 is approximately 5 rfr due to the panel holder 3! It is held at n. Further, a neck portion 8 is formed below the funnel portion 4, and a valve exhaust pipe 9 is provided in this neck portion 8.
The electron gun 10 which is connected in series is sealed in advance. The end of the valve exhaust pipe 9 is inserted into the hose 11, and the panel part 1,
It is connected to a pump device 12 that can supply and exhaust air into the valve formed by the funnel part 4 . The apparatus thus set up is placed in a heating furnace, and heat treatment is performed according to the temperature schedule shown in FIG.

First, the temperature was raised from room temperature to 390°C at a gradient of 8.5°C/min, and this temperature was maintained for one period. During this temperature raising and heat retention process, the organic material adhering to the inner surface of the face plate of the panel 1 is decomposed, and at the same time, air is introduced from the valve exhaust pipe 9 at a rate of 5 liters/minute at room temperature and pressure. Air flows from the neck part 8 where the electron gun 10 is located, passes through the funnel part 4, and flows out from the gap between the seal surfaces 2 and 5 as shown by the arrow, so the reducing gas from which the organic material is decomposed flows out from the gap together and towards the electron gun. There is no reaction between the electron gun and the electron gun. After holding the powder at 390° C., the panel holder 3 is lowered to bring the sealing surface 2 of the panel portion 1 and the sealing surface 5 of the funnel portion 4 into contact with each other via the solder glass 7.

At this time, the inflow of air from the valve exhaust pipe 9 is stopped. Next, the temperature was increased to 430°C at a gradient of 3.5°C/min, and at this temperature
keep it in tact.

In this temperature raising and heat retention step, the solder glass 7 is crystallized and the panel 1 and the funnel 4 are fused together. Next 4
Hold 12 powders at a gradient of 3.5 to 00°C.

In this temperature-lowering and heat-retaining step, the pump device 12 exhausts the air inside the valve, residual gas, etc. from the valve exhaust pipe 9, and makes the inside of the valve a high vacuum. When a color picture tube is manufactured using this process, when the organic material decomposes, a gas that does not easily or does not react with the electron gun flows in from the valve exhaust pipe, creating a flowing gas atmosphere in the electron gun. It does not react with gas generated by thermal decomposition even at high temperatures, eliminating electron emission defects at the cathode.

In this embodiment, air is used as the gas flowing in from the valve exhaust pipe 9, but oxygen gas, nitrogen gas, and rare gases, which are generally used as non-reducing gases, may also be used as long as they have a property that does not easily react with the electron gun. be able to. Furthermore, air and oxygen gas not only protect the electron gun but also have the effect of making it easier to thermally decompose organic matter adhering to the panel 1. Regarding the temperature of the gas, room temperature was used in this example, but if the inflow rate is small, the funnel part 4
By the time it comes into contact with the glass, it is heated by the surrounding heat, but if the amount exceeds, for example, several tens of liters per minute, the heat in the furnace alone will not heat the glass, and the temperature difference between the gas and the funnel part 4 will cause the glass to heat up. The finished funnel portion 4 may be damaged. Therefore, it is necessary to bring the temperature of the flowing gas close to the temperature of the funnel portion 4 in advance. Further, in this embodiment, the electron gun 10 was sealed in the funnel part 4 in advance, but a method is used in which the stem glass of the electron gun and the neck end of the funnel part are fused during the process with solder glass. You can also do that.

Note that the panel 1 and the funnel portion 4 may be arranged with the funnel portion 4 facing upward. As described above, according to the method for manufacturing a cathode ray tube of the present invention, the sealing surface of the panel portion having a fluorescent film containing an organic material on the inner surface is opposed to the sealing surface of the funnel portion joined thereto, and at least A solder glass is attached to one side, and gas is introduced from the valve exhaust pipe connected to the electron gun placed in the neck of the funnel part, and the gas is passed through the gap where the sealing surfaces face each other. By including the steps of heating the cathode while it is flowing out to decompose and remove the organic material, and then bonding the sealing surfaces to each other, the manufacturing cost can be significantly reduced without deteriorating the electron emission characteristics of the cathode.

[Brief explanation of drawings]

FIG. 1 is a front view of a color picture tube manufactured according to an embodiment of the cathode ray tube manufacturing method of the present invention, and FIG. 2 is a graph of the temperature schedule. 1...Panel part, 2,5...Seal surface, 3...Panel holder, 4●●●●●● Funnel part, 610I◆●Valve holder, 7.・・・・・・
・Solder glass, 8...Neck part, 9...
...Valve exhaust pipe, 10...Electron gun, 11...
...Hose, 12...Pump device.

Claims (1)

[Claims] 1. A sealing surface of a panel portion having a fluorescent film containing an organic material on the inner surface and a sealing surface of a funnel portion to be joined thereto are opposed to each other, and at least one of the sealing surfaces is provided with solder glass. In the furnace, gas is allowed to flow in from a valve exhaust pipe connected to the electron gun disposed in the neck of the funnel, and while this gas is allowed to flow out from the gap where the sealing surfaces face each other, A method for manufacturing a cathode ray tube, comprising the steps of heating to decompose and remove organic materials, and then bonding the sealing surfaces to each other. 2. The method for manufacturing a cathode ray tube according to claim 1, wherein the gas is one that does not easily or does not react with the electron gun. 3 The gas is a noble gas,
3. The method for manufacturing a cathode ray tube according to claim 1 or 2, wherein one or more of nitrogen gas, oxygen gas, and air is used.