JPH01194235A - Manufacture of cathode-ray tube - Google Patents

Abstract

PURPOSE:To increase the strength of a film and provide electrostatic charging preventive effect without deteriorating the electrical characteristics by coating a material, which assumes glare-proof effect and/or charging preventive effect by means of baking, over the surface of screen of a cathode-ray tube, and by baking it with laser beam. CONSTITUTION:As a material to assume glare-proof effect and/or charging preventive effect by means of baking, silica coat liquid containing ethyl silicate as main component or a mixture solution of ethyl silicate, tin oxide, and indium oxide is sprayed over the surface of a heated screen, followed by baking by means of scanning with laser beam.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a cathode ray tube, and more particularly to a method for imparting anti-glare or anti-glare and antistatic effects to the surface of a cathode ray tube image surface.

[Conventional technology]

Conventionally, the following methods have been implemented to obtain anti-glare and/or antistatic effects. That is, 5iCQa・5i(
OR) A method in which a mixed solution of a and alcohols or esters is sprayed onto the image surface of the finished floor of a cathode ray tube and baked at 80 to 200°C in an electric or gas furnace to form an anti-glare film (Jikko Sho 5O- 26277) and silicon halide or silica sol solution mixed with halides such as Fe, Co, Ni, Cu, Ag, or nitric acid or sulfate, is sprayed onto the surface of the cathode ray tube image surface and baked at around 200°C to provide anti-glare and anti-glare properties. This method includes a method of forming a film having an antistatic effect. The reason why these coatings are formed after the completion of the cathode ray tube is to avoid damage to the coating during the manufacturing process of the cathode ray tube.

[Problem to be solved by the invention]

In the conventional method described above, heating a completed cathode ray tube at a high temperature deteriorates its electrical characteristics such as emission characteristics, so it was fired at a relatively low temperature (200° C. or lower). However, in such low-temperature firing, the former method has a problem in that the strength of the film is insufficient, and the latter method does not provide a sufficient antistatic effect.

The object of the present invention is to ensure the strength and antistatic effect of the coating without deterioration of the electrical properties. .

[Means to solve the problem]

In order to achieve the above object, in the present invention, a material that exhibits an anti-glare or anti-glare and antistatic effect when fired is applied to the surface of the picture surface of a cathode ray tube, and then this coating film is fired using carbon dioxide gas or a YAG laser. It is something to do.

[Effect]

By using carbon dioxide gas or a YAG laser, the coating film and the very surface of the cathode ray tube glass can be fired at high temperatures in a short time without causing distortion to the glass or deteriorating its electrical characteristics.

〔Example〕

The present invention will be explained below with reference to Examples.

Example 1 Face glass transmittance of 14 type 0.31 mm pitch 57
% color display tube was thoroughly washed with a neutral detergent, rinsed with running industrial water for 1 minute to thoroughly remove the neutral detergent, and then rinsed with deionized water. This is 0.3
Dry by blowing dry air through a μs dust removal filter. A parallel beam carbon dioxide laser (output power 10 W) with a vertical beam width of 50 cm and a horizontal beam width of 2 cm was scanned at a scanning speed of 90 nu/see on the image surface of the color display tube.
Make a U-shaped motion and irradiate the entire surface twice to bring the surface temperature to 6.
After the temperature was lowered to 0°C, a silica coating liquid containing ethyl silicate as a main component (commercial name Nire Sun Coat Liquid: manufactured by Asahi Glass Co., Ltd.) was applied at a flow rate of 5 mQ/see and a volume ratio of liquid to air of 1:3.
After spraying the panel surface to a thickness of about 1 μm from a distance of a, the panel surface was irradiated twice with a carbon dioxide laser having the beam width and output power of 100 W at a scanning speed of 70 mm/see. At this time, the temperature of the film had reached about 600°C. A comparison of the characteristics with the current electric or gas heating furnace method, which cools this and heats it to about 200° C., shows the results shown in the table below.

The results show that both the eraser resistance and boiling water resistance are significantly improved. The reason for this is generally said to be that the adhesion between Si and the glass interface in this type of silica coating system is mainly composed of siloxane bonds, and a portion thereof has a structure of OH groups. The smaller the amount of OH groups, the higher the strength. It is thought that this is because when firing with a laser, the bonded portion between the glass and the silica coated film is heated to a high temperature, which causes a reaction to remove OH groups and increases the proportion of siloxane bonds.

Example 2 Face glass transmittance of 14 type 0.31 mm pitch 57
% color display tube was washed, dried, and preheated in the same manner as in Example 1 to bring the surface temperature to 40°C, and then treated with a liquid containing ethyl silicate and conductive substances such as tin oxide and indium oxide (commercial name: Colcoat EC920 Nicol). Flow Jf 7 m! /sec, with a liquid to air volume ratio of 1:3, spray approximately 1μ onto the panel surface from a distance of 50am with a spray gun.
The fine particle film (average particle diameter: 40 -) sprayed to the thickness of the surface was heated in the same manner as in Example 1 using a carbon dioxide laser having the beam width and output power described above. This was cooled and its performance was compared with conventional gas or electric furnace heating. However, the number of times of heating was six times, three times that of Example 1.

Test A: Eraser resistance (number of scratches visible under conditions according to MIL-C-675C) Testro: Boiling water resistance (change in gloss value after immersing in boiling water for 30 minutes, the smaller the better) Test C: Alkali resistance (PHII 2 in ammonia solution
Change in gloss value after 4 hours of wear) Test D knee 40°C to 70°C 74 hour cycle test Change in resistance after 300 hours (the smaller the better) As you can see from this result, the durability is good. It also has low surface resistance. The reason for this is thought to be that under low-temperature firing conditions, the conductive substance is difficult to turn into an oxide, and this film moves in an ion-conductive manner in the adsorbed water. On the other hand, a film fired at a high temperature using a laser efficiently heats the surface of the film and the face glass to a high temperature, so it is said that the film easily becomes an oxide and exhibits electron conductivity.

Example 3 A 14-inch color display tube was washed and dried in the same manner as in Examples 1 and 2, and then preheated with a carbon dioxide laser. A sol solution containing antimony oxide and tin oxide as main components (product name: Cerames Ninigi Chemical) was added to the Nire Sun Coat solution. Mix 10% of the company II!ri by volume and spray under the same spray conditions as Example 2.
．． Create a fine particle film with a thickness of 0 μm and use a YAG laser with a wavelength of 1.06p (the YAG laser absorption rate of this film is 70%).
was irradiated six times with the same parallel beam as in Example 1 at an irradiation output of 60 W and a scanning speed of 40 ml sec, and the performance of the film was examined after cooling. The results are shown in the table below. When using a YAG laser, the depth of the beam penetrating the film and panel face can be controlled by changing the concentration of the substance that absorbs the wavelengths mentioned above, under conditions that do not cause thermal processing distortion. It has the characteristic of being able to be fired at high temperatures.

〔Effect of the invention〕

Claims (1)

[Claims] 1. A method for producing a cathode ray tube, which comprises the steps of: applying a material that exhibits anti-glare or anti-glare and antistatic effects when fired on the surface of the picture surface of the cathode ray tube; and after application, firing the coating film with a laser beam.