JPS62147629A - Manufacture of image display tube - Google Patents

Abstract

PURPOSE:To obtain an image display tube with good emission by heating and evacuating the parts coated with an aquaduck and replacing the internal atmosphere with a gas which is free from damaging the cathode during the following cooling step. CONSTITUTION:After the parts are placed in a degassing furnace, it is evacuated 1 by a diffusion pump. Either next or simultaneously, the furnace is heated 2 to about 450 deg.C to remove the water contained in an aquaduck. When the parts are taken out from the heated furnace after it is cooled, the parts easily adsorb water and the effect of degassing is almost eliminated. Then, gas replacement 3 is performed at about 450 deg.C. After that, the internal atmosphere of the degassing furnace is replaced with dry nitrogen and the furnace is cooled 4. During this process, the aquaduck adsorbs nitrogen until the aquaduck is saturated. Due to the above process, only nitrogen gas is discharged by heating during the following fusion. Therefore, the cathode is prevented from being damaged, thereby producing an image display tube with good emission.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a method of manufacturing an image display tube.

Conventional Technology Conventionally, carbon has been used as a conductive material in electron tubes. FIG. 2 is a sectional view of a cathode ray tube showing one example. Carbon 23 (hereinafter referred to as Aquaduck) is applied to the 7-channel channel 21 in order to apply the same voltage as the anode 22.

In the manufacturing process of the cathode ray tube, a face plate 26 provided with a shadow mask 24 and a funnel 21 whose inner surface is coated with Aquadac 23 and dried are sealed together via a frit 26. This sealing is performed by heating to 4so'C and 13 degrees.

Next, the electron gun 27 is inserted, bonding is performed, the chip tube 28 is evacuated, and baking is performed to complete the sealing.

FIG. 3 is a sectional view of the flat image display tube. This assembly process is as follows. A deflection electrode 32 and an electrode group 33 including an electron gun are assembled in the container 31, and a back metal plate 36 is sealed via a frit 34. The sealing temperature is about 450''C, which is the same as that of a cathode ray tube, and the chip tube 36 is then evacuated and then baked and sealed.

Problems to be Solved by the Invention However, in the above-described process for flat panel image display tubes, the deflection electrodes 32. Since Aquaduck is used for the electrode group 33, gas such as water comes out from the Aquaduck during sealing. The electrode group 33 includes a cathode 37, which is damaged by this gas and after being sealed off,
The problem was that the emission characteristics deteriorated. Furthermore, even when parts coated with Ag or Adatsu were heated and degassed in advance, since the surface was porous, moisture was adsorbed again during storage and assembly, so little improvement in emission characteristics was observed.

In view of the above problems, the present invention provides a method for manufacturing an image display tube having a cathode that exhibits good emission characteristics even when parts using an aqua adapter are used.

Means for Solving the Problems In order to solve the above-mentioned problems, the method for manufacturing an image display tube of the present invention heats and degasses the parts coated with Aquaduck before assembling the parts to raise the maximum temperature or lower the temperature. This includes a step of replacing the inside with a gas that does not affect the cathode, such as nitrogen, carbon dioxide, or an inert gas such as Ar.

Function The present invention uses the above-described process to allow Aqua Duck to adsorb water until it is saturated with gas that does not cause damage to the cathode after degassing, which previously absorbed water after degassing. It cannot adsorb gases such as water that would have an adverse effect on the inside, and the cathode will not be damaged during sealing.

EXAMPLE Hereinafter, a method for manufacturing an image display tube according to an example of the present invention will be explained with reference to process diagrams.

FIG. 1 is a block diagram of heat treatment of parts coated with Aquaadapter in an embodiment of the present invention.

First, parts are placed in a degassing furnace, and exhaust 1 is performed using a diffusion pump, followed by heating 2.
Do this. The degree of vacuum at this time is 1 x 1O-5 Tor
r or less. In this example, heating is performed to 460°C to remove moisture from Aquaduck.

If it is cooled and taken out in this state, it will become more likely to adsorb water and the degassing effect will almost disappear. Therefore, gas replacement 3 is performed at 450'C. Here, cooling 4 is performed by substituting with dry nitrogen. Here, the nitrogen gas pressure was maintained at 1 atm. This process allows the aquaduck to adsorb nitrogen and become saturated. By changing the process in this way, the only gas released by heating in the subsequent sealing process is nitrogen, and there is no damage to the cathode, making it possible to obtain an image display tube with good emission characteristics.

Although nitrogen is used as the replacement gas in the above embodiments, carbon dioxide gas or an inert gas may also be used.

Effects of the Invention As described above, the present invention heats and exhausts parts coated with Aqua Adapter, and in the cooling process replaces the gas with gas that does not damage the cathode, thereby preventing the cathode from being affected even during the sealing process. Accordingly, it is possible to provide an image display tube that is free from radiation and exhibits good emissions.

[Brief explanation of drawings]

Fig. 1 is a process diagram of processing parts coated with Aquadac using the method for manufacturing an image display tube according to the present invention, Fig. 2 is a partially cutaway cross-sectional view of a cathode ray tube, and Fig. 3 is a cross-section of a flat image display tube. It is a diagram. 21... Funnel, 23... Carbon (Aqua Duck), 27... Electron gun, 33...
... Electrode group, 34 ... Frit. Name of agent: Patent attorney Toshio Nakao and 1 other person 1st
Figure box 1' ↓ ↓ ,・Box 4 Figure 3 31 Each profit

Claims (1)

[Claims] The electrodes constituting the electrode structure coated with carbon or the vacuum envelope whose inner surface is coated with carbon are heated in advance, degassed under vacuum, and the temperature is reached at its maximum temperature, or during the cooling process, the gas is replaced with an inert gas, and the inside is heated. A method for manufacturing an image display tube, characterized in that the vacuum envelope is sealed in a state in which the gas-substituted electrode assembly is provided.