JPS638573B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for forming a color picture tube fluorescent surface;
In particular, the present invention relates to an improvement in the method of forming the fluorescent surface of a color picture tube by a so-called dry process in which a phosphor is applied in powder form to a face panel.

The phosphor surface of a color picture tube consists of three-color phosphor films coated in dots or stripes at predetermined locations. However, a method is already known in which a predetermined portion of a film is exposed to light through a shadow mask and the photoreaction that occurs there is utilized.

That is, a photosensitive film is formed by coating the inner surface of the face panel with a photosensitive resin mainly composed of diazonium salt, and when the parts of this photosensitive film where the phosphor is to be coated are exposed to light, the phosphor is applied to the inner surface of the face panel. The zinc chloride produced in the exposed areas absorbs moisture from the atmosphere and becomes sticky, so spraying phosphor powder of a predetermined luminescent color onto the inner surface of the face panel can reduce the stickiness of the photosensitive film. This phosphor powder will adhere to only the exposed areas and the phosphor will be coated. After performing this process of spraying the phosphor powder and applying adhesive to each of the three primary light phosphors, ammonia gas is applied to the photosensitive film to expose the areas where the phosphor powder has been adhesively applied. The fluorescent surface is formed by fixing the transparent film as being insoluble in water, and then washing out excess residue with an organic solvent.

This method is a type of so-called dry process.
Compared to the conventional method in which each color phosphor is made into a photosensitive slurry and sequentially coated, exposed, and washed and developed, the photosensitive film can be formed only once, which shortens the work process. This method has advantages such as being economical because the unnecessary part that does not adhere to the adhesive part by spraying the light substance in powder form can be blown away and recovered in powder form with an air spray.

However, since the above-mentioned photosensitive resin contains diazonium salt, it exhibits an extremely low hydrogen ion concentration (PH), and when this photosensitive resin film is applied to a face panel, it has the disadvantage that coating unevenness tends to occur. was. This uneven coating results in a difference in phosphor-receiving ability between areas where unevenness occurs and areas where unevenness does not occur, making it difficult to obtain a good fluorescent surface. In particular, with black matrix type phosphor surfaces where the space between the phosphor films is filled with graphite, the level of the coating unevenness is significantly reduced. It had become a big problem.

Therefore, the present invention has been made to eliminate the above-mentioned conventional drawbacks, and its purpose is to improve the coating characteristics of a photosensitive resin film by a simple method. That is, as a result of conducting various experiments to achieve the above objective, we found that, prior to coating the photosensitive resin film, the inner surface of the face panel was prepared so that the pH was approximately the same as that of the photosensitive resin film. It was discovered that the coating unevenness level could be significantly improved by applying the treatment, and as a result, an extremely good fluorescent surface could be obtained. The method for forming a fluorescent surface according to the present invention will be explained in detail below using Examples.

Example 1 First, the inner surface of the face panel of a 14-inch black matrix color picture tube was washed with about 6wc% hydrochloric acid aqueous solution for about 10 seconds, and then with pure water for about 30 seconds to make it acidic. A photosensitive resin of composition 1 is applied to the inner surface of the face panel to a thickness of 0.6 to 1.0 μm.
After applying the green phosphor to a thickness of 100 mL and drying it, combine the shadow mask with the face panel, and irradiate the area where the green phosphor is to be applied for 2 to 3 minutes with light at an intensity of 15 to 20 W/m ² through the shadow mask. Expose. As a result of this operation, the diazonium salt is decomposed at the exposed areas of the photosensitive coating film to produce zinc chloride, which adsorbs moisture in the air and produces uniform high tackiness. The atmosphere at this time was 25±5℃, 55±6℃.
Temperature and humidity of around 30% are appropriate. After spraying green phosphor powder here. When you air spray,
The phosphor is uniformly deposited at a rate of 2.5 to 3 mg/cm ² only in areas where the film becomes sticky due to exposure.
Subsequent exposure, phosphor spraying, and deposition operations for the blue and red phosphors form dots or stripes of three colored phosphors on the interior surface of the face panel. The color picture tube obtained by this method had no uneven coating of the phosphor, and a high-quality phosphor surface was obtained.

Composition 1 Γ Alginate propylene glycol ester
0.6wt% Γ P-N,N-dimethylaminobenzenediazonium zinc chloride double salt 3wt% Γ Pluronic L-92 (oxyethylene propylene block copolymer) 0.003wt% Γ Water Remaining Example 2 First, 14-type black matrix color The inner surface of the face panel of the picture tube was washed with about 2 wt% citric acid aqueous solution for about 10 seconds, and then with pure water for about 30 seconds to make it acidic. A good fluorescent surface with no coating unevenness was obtained.

In the above example, when applying a photosensitive resin film mainly composed of an acidic diazonium salt to the inner surface of the face panel, the inner surface of the face panel was made to have approximately the same pH as the photosensitive resin film. Although we explained the case of acid treatment,
The present invention is not limited to this, and when applying an alkaline photosensitive resin film, it is possible to perform alkaline treatment on the inner surface of the face panel so that the pH is almost the same as that of the photosensitive resin film. Of course, exactly the same effect can be obtained.

As explained above, according to the present invention, the advantage of the conventional dry process of economical use of the phosphor, generally short and simple steps, and a good coating of the phosphor without any unevenness can be achieved. An extremely excellent effect can be obtained in which a fluorescent surface can be easily and stably obtained.

Claims (1)

[Claims] 1. Apply a photosensitive resin film to the inner surface of the face panel, expose the desired areas of the photosensitive resin film to be coated with phosphor, and remove the exposed areas of the photosensitive resin film by photoreaction and moisture in the atmosphere. In a method for forming a phosphor surface of a color picture tube, the phosphor surface of a color picture tube is coated by applying a phosphor powder to a desired location by using the tackiness of the photosensitive resin. A method for forming a fluorescent surface of a color picture tube, characterized in that, prior to applying a film to a face panel, the inner surface of the face panel is surface-treated so that it has approximately the same pH as the photosensitive resin film. .