JPS62157638A - Manufacture of color cathode-ray tube - Google Patents

Abstract

PURPOSE:To intensity adhesive power on a phosphor screen easily, by forming phosphor powder layers for three primary colors on the inner surface of a valve face and applying, thereafter, a humidifying process being followed by a fixing process using ammonia gas. CONSTITUTION:A photoadhesive film 2 mainly composed of diazocompound is laid over the inner surface of the valve face 1 of a color cathode-ray tube, and a specific position thereof is subjected to optical exposure through a photo- mask 4 so that a stripe-shaped red luminous phosphor layer 3R may be formed after adhesiveness being generated on said film. A stripe-shaped green luminous phosphor layer 3G and blue luminous phosphor layer 3B are also formed in sequence by repeating the similar operations. Thereafter, those layers are subjected to humidification among air 5 of about 80% humidity, subsequently subjected to a fixing process by means of ammonia gas 6 so that the phosphor surface may become insoluble in water. Accordingly, a phosphor screen having intensive adhesive power and well standing a cleaning process can be easily obtained in this way.

Description

[Detailed Description of the Invention] (1) The present invention relates to a method of manufacturing a color cathode ray tube using a so-called dry method of forming a phosphor screen, in which a phosphor is applied in powder form to a bulb face, and in particular relates to improving the adhesion strength of the phosphor screen. be.

The phosphor screen of a color cathode ray tube consists of three-color phosphor films that emit red, green, and blue light and are regularly formed in the shape of dots or stripes.

The method for forming the phosphor screen of such a color cathode ray tube is as follows:
A dry method is being considered. In this method, a photo-adhesive composition containing a diazo compound as a main component is applied, selectively exposing predetermined positions of the film coated with the adhesive composition to create tackiness in the exposed areas, and then applying the photo-adhesive composition. Powder phosphor is applied to the exposed area.

Next, the process of removing undesired phosphor adhering to unexposed areas by development is repeated for three-color phosphor powders emitting red, green, and blue light, and then ammonia gas is applied to the formed phosphor surface. The photo-adhesive composition in the area to which the phosphor powder is attached is made insoluble in water by fixing, and the excess residue is washed out with water and a solvent to form a phosphor screen. be.

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However, even if the fixing action using ammonia gas is performed after the phosphor screen is formed as in the conventional method, the photoadhesive composition does not become insoluble in water over the entire phosphor screen, and a portion of the phosphor screen peels off when washed with water. There were often problems.

Further, even if the time for the fixing action by ammonia gas is increased, the effect is not so great, and the same problem remains.

The reason why a part of the phosphor screen peels off is probably as follows. First, in order to make the attached phosphor screen insoluble in water, water-soluble zinc chloride (ZnC), which is a decomposition product of the photoadhesive composition in ammonia gas and water, is mixed with water-insoluble zinc hydroxide. (Zn(OH), ), but the phosphor screen must have enough moisture to change zinc chloride to zinc hydroxide. Therefore, in the conventional case, some portions of the phosphor screen lack moisture and zinc chloride does not change to zinc hydroxide, resulting in the above-mentioned problem of partial peeling when washed with water.

,,'' The present invention was proposed in view of the above-mentioned problem, and after attaching three-color phosphor powders that emit red, green, and blue light to predetermined positions, the formed phosphor screen is humidified. The purpose of this invention is to present a new and improved method of manufacturing a color cathode ray tube that is subsequently fixed with ammonia gas.

To summarize, the present invention is a method for forming a phosphor screen, in which predetermined positions of a photo-adhesive film mainly composed of a diazo compound formed on the inner surface of a bulb face are selectively exposed to make it sticky, and the exposed parts are In a method for forming a phosphor screen, the steps of applying phosphor powder and removing the phosphor powder adhering to unexposed areas through development are repeated to form a three-color phosphor powder layer, and then a fixing treatment with ammonia gas is performed. , discloses a method for manufacturing a color cathode ray tube, characterized in that the phosphor powder layer is humidified prior to the fixing treatment with ammonia gas, and the adhesion of the phosphor powder layer is strengthened after fixing.

1 Dish In the present invention, after humidifying the three-color phosphor powder layer emitting red, green, and blue light, a fixing action is performed using ammonia gas, so that the phosphor surface can be made evenly insoluble in water, and the adhesion strength can be improved. A strong phosphor film can be obtained.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing a color cathode ray tube according to the present invention will be described based on embodiments with reference to the drawings.

The figures show cross-sectional views of the bulb face portion in each step of the phosphor screen forming method in the manufacturing process of the color cathode ray tube of the present invention.

First, 4% by weight of PN,N dimethylaminobenzenediazonium zinc chloride double salt and 0.3% by weight of polyvinyl alcohol (trade name, Kuraray Boval 224, manufactured by Kuraray ■) were applied to the inner surface of the valve face 1.

Surfactant (trade name, PP-230, Kao Atlas-W
) A photoadhesive composition consisting of 0.004 fflffi%, ethylene glycol and 0.5% water balance was spin-dried and applied to form a photoadhesive composition having a thickness of about 0.3 μm, as shown in Figure (a). A sexual film 2 was formed.

Next, using the photomask 4, a predetermined position where the red light-emitting phosphor stripe 3R is to be formed is exposed (i!
Light conditions: 18 w/rd x 100sec)'
L. This exposed area is brought into contact with humid air with a humidity of about 45 to 55% for 10 seconds to produce adhesiveness 2a as shown in Figure (b).

Next, a red-emitting phosphor powder was applied, and then the red-emitting phosphor powder adhering to the unexposed portions was removed by air spray to form a red-emitting phosphor stripe 3R. Thereafter, a green-emitting phosphor stripe 3G and a blue-emitting phosphor stripe 3B were formed by repeating the same steps.

In this way, a phosphor layer 3 as shown in Figure (C) is formed.

Next, this phosphor layer 3 was brought into contact with humid air 5 having a humidity of about 80% for 30 seconds, and then fixed with ammonia gas 6. Figures (d) and (e) show processing conditions using moist air 5 and ammonia gas 6, respectively.

Regarding the treatment conditions, it is desirable to set the humidity and time within the following ranges.

Humidity: Approximately 60-90% is a suitable range.

If it is less than 60%, no effect will be achieved, and if it is more than 90%, the powder particles in the phosphor layer will become too wet and will easily peel off.

Time: A range of about 20 seconds to about 2 minutes is sufficient.

It has been experimentally confirmed that the above-mentioned humidification treatment before fixing with ammonia gas is effective in improving the adhesion of the phosphor screen.

After this fixing process, an aqueous solution 7 consisting of 80% by weight of ethyl alcohol and 20% by weight of water was flowed over the inner surface of the bulb face 1 to remove excess residue and form a desired phosphor screen 8. This state is shown in Figure (f).

The phosphor screen 8 thus formed was a very strong film that did not peel off over the entire area even after thorough cleaning.

In this embodiment, we have described a color cathode ray tube that has a phosphor screen that emits three colors of red, green, and blue light, but it can also be applied to a color cathode ray tube that forms a black stripe or uses a beam index method. Not even.

As explained above, the phosphor screen forming process in the color cathode ray tube manufacturing method according to the present invention is extremely effective in obtaining a phosphor screen with strong adhesion that can withstand sufficient cleaning. This has practical effects such as preventing the formed phosphor screen from peeling off.

[Brief explanation of drawings]

The figures are cross-sectional views of the bulb face portion in each step of forming a phosphor screen in the method of manufacturing a color cathode ray tube according to an embodiment of the present invention. 1...Valve face. 2...Photoadhesive film. 3...phosphor layer. 3R, 3G, 3B...phosphor stripes that emit red, green, and blue light. 4...Photomask. 5...Moist air. 6...Ammonia gas. 7...Aqueous solution containing an organic solvent. 8... Fluorescent screen patent applicant Kansai NEC Co., Ltd. lt:i;'. :I-

Claims (1)

[Claims] Predetermined positions of the photo-adhesive film, which is mainly composed of a diazo compound and formed on the inner surface of the bulb face, are selectively exposed to light to make it sticky. Phosphor powder is applied to the exposed areas, and the unexposed areas are developed. In a method for forming a phosphor screen, in which a step of removing the adhered phosphor powder is repeated to form a phosphor powder layer of three colors, and then a fixing process is performed using ammonia gas, the phosphor powder layer is fixed using ammonia gas. A method for manufacturing a color cathode ray tube, characterized in that humidification treatment is performed prior to processing and the adhesion of a phosphor powder layer is strengthened after fixing.