JPH024093B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a cathode ray tube, and in particular, an object of the present invention is to improve the process of baking and degassing the cathode ray tube to improve its characteristics.

When manufacturing a cathode ray tube, as shown in the figure, a fluorescent surface 2 is formed on the inner surface of a panel 1, and a funnel 3 having a conductive coating 5 formed thereon is sealed at a predetermined location on the inner surface of the panel 1. An envelope 4 is formed, at least one electron gun 6 is disposed in a neck portion 7 of the envelope, and a mount structure 9 supported by a glass stem 8 is hermetically sealed within the neck portion 7. do.

Next, the tube is evacuated to a fairly low pressure by a vacuum evacuation device through the glass evacuation capillary 10 connected to the stem, and baked at a temperature of approximately 350° C. to 450° C. during this evacuation. The exhaust capillary is then sealed or tipped off. In conventional manufacturing methods, near the end of the evacuation and baking steps and prior to chip-off, the mount structure is heated by high frequency heating or the like to degas it. On the other hand, the cathode assembly is also heated by supplying electricity to the cathode heater to decompose the cathode coating material and degas it. After heating and degassing in this manner, the tube is tipped off and vacuum sealed. Next, getter 1 installed in the pipe
1 is flashed to form a getter film on the tube wall, thereby creating a high vacuum inside the tube. Thereafter, a cathode ray tube as a product is obtained through predetermined processes such as aging.

In this way, a cathode ray tube with normal operating characteristics can be obtained, but in order to effectively stabilize the operating characteristics and extend the lifespan, the above-mentioned processing conditions and their combinations have been studied and improvements have been made. It is. For example, when heating the mount structure during exhaust, the heating temperature, heating time, heating location, etc.
Also, the heating temperature and heating time of the cathode structure, as well as the combination of these two treatments, are being studied. Furthermore, various studies have been conducted on the aging method of the electron gun in subsequent steps, and efforts are being made to improve tube characteristics.

However, in these various processing operations, the methods for treating residual gas and occluded gas in the pipes during and after exhaustion are still insufficient.In other words, degassing and re-adsorption of emitted gas are insufficient, and there is still room for improvement. It was hot. To further explain this, the valve as the envelope is
It is heated to a temperature of 350° to 450°C to degas it,
Due to the structure of the baking oven, the central part of the valve is generally heated to the above temperature, and the temperature decreases as it approaches the funnel, neck, and opening, and the temperature decreases to 40° at the exhaust tube. The temperature is as low as ~50°C, and since the tip-off section is covered by the case of the heating coil, the temperature drops even further, making degassing insufficient. However, when the glass is chipped off after exhaust, the temperature near the glass melting area rises to approximately 800℃.
At that time, it will be vacuum sealed with a large amount of gas being released. Furthermore, the gettuter and gettuta container reach high temperatures of over 1000°C during the gettuta flashing, so if the gettuta and gettuta container are treated at the same temperature as the envelope, a large amount of gas will be released from the gettuta and gettuta container. As described above, there was still room for improvement in degassing.

In addition, regarding the insufficient prevention of re-adsorption of emitted gas, the temperature of the valve and conductive coating decreases after high-temperature sealing of the panel and funnel prior to enclosing the mount structure in the neck part. Gas adsorption to the mount structure enclosed in the mount structure occurs, but this has been dealt with by replacing the stabilizing gas with N ₂ gas. However, when degassing by heating the mount structure and degassing by heating the cathode structure near the end of the exhaust cycle, the temperature of the exhaust capillary part is approximately 200°C or less, and when heating the cathode structure, the temperature of the mount structure other than the cathode structure is Most of the temperature is below about 250°C, and even if degassing is performed at this low temperature, the gas released into the pipe will not be re-adsorbed into the exhaust thin pipe or the mount structure. I can't escape it. Furthermore, when being chipped off, gas in the exhaust gas from the chipped off part is not sufficiently vented, and a large amount of gas is re-adsorbed and then heated to a high temperature of approximately 800°C, causing gas release. This released gas is chipped off without being exhausted, and most of the released gas is confined within the pipe.

In this way, gases released from various locations will remain in the pipe, but as the temperature of the envelope decreases after exhaust, the envelope and mount structure will absorb up to the saturated adsorption amount at the lowered temperature. The remaining gas is adsorbed, and the amount of gas floating inside the pipe appears to be reduced, leaving the inside of the pipe in good condition. However, when the cathode ray tube is operated, the gas stored in the envelope and mount structure rises in temperature, causing the mount structure to rise in temperature.
Gradually releases adsorbed gas. Since the treatment of the residual gas is thus insufficient, gas is released even after the getter is flushed, resulting in the same result as the getter not being sufficiently effective. Along with that,
Such released gases are often activated gases and are therefore very harmful to the cathode material after pyrolysis. For example, oxide cathode materials reach a temperature of about 700° to 800°C during operation after thermal decomposition, but even when the cathode temperature is below about 400°C, gas poisoning can occur in an atmosphere of H ₂ O gas at about 10 ^-3 Torr. For example, 2H ₂ O+
BaO→Ba(OH) ₂ is formed. This Ba(OH) ₂ has a low melting point of about 80°C, so it easily melts when heated at low temperatures, causing coarse crystals and ultimately deteriorating the performance of the cathode material. This phenomenon often occurs when an atmosphere of about 10 ^-3 Torr to several Torr is formed when heating the mount structure or the cathode structure.

The present invention has been made in view of these points, and it is an object of the present invention to provide a method for manufacturing a cathode ray tube, which improves the baking and degassing steps and improves the tube characteristics. That is, the method is characterized in that the cathode assembly is chipped off without being thermally decomposed, then getter flushed, and then the cathode assembly is thermally decomposed.

Examples of the present invention will be described below. After the panel and the funnel are sealed together, a conductive film is formed at a predetermined position on the inner wall of the bulb, which is the envelope, and then the mount structure is enclosed within the neck portion. Exhaust with a vacuum pump, and rotate the valve approximately 380 degrees during the exhaust.
Bake at 450℃ and degas. Next, the enclosed mount structure is heated with high frequency to approximately
After degassing for 10 minutes, heat the exhaust tube part of the stem to about 800℃ and tip it off. After sealing in this manner, the getter disposed inside the tube is flashed to form a getter film on the inner wall of the tube. Next, the cathode heater is energized to heat the cathode assembly and perform thermal decomposition treatment. At this time, the mount structure is
It will be even more effective if heated to 200℃ or higher.
Thereafter, it is made into a product through predetermined processes.

In this way, the cathode assembly is not subjected to thermal decomposition treatment before chip-off, but the getter flush treatment after chip-off adsorbs the residual released gas that was trapped in the tube during chip-off, creating a good atmosphere inside the tube, and then removing the cathode assembly. Pyrolysis treatment is performed.
At this time, the gas released from the cathode due to thermal decomposition and the gas occluded in the cathode structure are released and adsorbed by the getterflash film. Therefore, when this cathode ray tube is operated, the temperature of the cathode structure rises, but in the present invention, compared to the conventional one, there is less occluded gas, and therefore less gas is released, and gas degassing and gas re-adsorption are prevented. This is a significant improvement and can contribute to improving tube properties.

Note that it is more effective if a second getter flushing step is provided after the thermal decomposition treatment of the cathode assembly as described above. When performing the first and second getter flush processes in this way, the second getter film is formed on the first getter film, creating an extremely good vacuum condition inside the tube, which improves the tube characteristics of the cathode ray tube. It will be further improved. In this case, the flash capacity of each getter is such that when a second getter is used, the second getter only needs to adsorb the gas released during the thermal decomposition treatment of the cathode assembly, and the first getter flashes after the chip-off process. It is preferable to increase the flash capacity of the getter. It is preferable that the getter, which is provided to adsorb the gas released during thermal decomposition of the cathode, be provided near the top of the neck of the envelope on the panel side near the mounting structure. At this time, if the getter flash is performed while heating the mount structure at a temperature of 200° C. or higher, no getter film will be formed on the surface of the mount structure due to the characteristics of the flash getter, and the getter film can be formed at the necessary neck portions. Further, if the cathode structure is heated to a temperature of 400° C. or higher while getter flushing is performed, the same effect as described above can be obtained. Furthermore, the getter flash may be performed while heating both the mount structure and the cathode structure. In this way, re-adsorption of the released gas to the mount structure can be prevented.

[Brief explanation of drawings]

The figure is a partially cutaway front view of the cathode ray tube. DESCRIPTION OF SYMBOLS 1... Panel, 2... Fluorescent surface, 3... Funnel, 5... Conductive coating, 7... Funnel neck, 9... Mount structure, 10... Exhaust tube, 11... Getter.

[Claims]

1 Opening of the final stage of two opposing electrodes located on the image receiving screen side of a multi-stage focusing electron lens in which three or more electrodes are made to face each other and two or more electrode gaps form an in-line main electron lens. Only the diameter D is made large so that D/S≧0.88 with respect to the mutual distance S of the holes, and the other electrode openings on the opposing surface are set such that D/S≦
Electron gun structure for color picture tubes characterized by its small diameter of 0.84.

Claims (1)

3. The method for manufacturing a cathode ray tube according to claim 1, wherein the getter flash is carried out while heating the cathode structure to 200° C. or higher, or heating the cathode assembly to 400° C. or higher, or both.