JPS6310529B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a fluorescent surface of a color picture tube by a so-called drive process in which a phosphor is formed in powder form on the inner surface of a face panel.

The fluorescent surface of a color picture tube makes the pixels on the screen red,
It consists of three-color phosphor films formed in dots or stripes at predetermined locations with precise dimensional accuracy in order to emit light from the three-color phosphors of green and blue.

The method of forming the fluorescent surface of such a color picture tube is to make each color's phosphor into a photosensitive slurry, apply this slurry to the inner surface of the face panel to form a film, dry it, and then pass it through a shadow mask. A method has long been used in which the process of exposing to light and then washing and developing with water is repeated for each color.
However, this method requires a large number of work steps and is not very productive.

In order to improve these points, a drive process method is being considered in which a phosphor powder is used instead of a photosensitive slurry. In this method, a photosensitive resin mainly composed of diazonium salt is applied to the inner surface of the face panel to form a film, and then exposed to light through a shadow mask to make the exposed areas sticky. The phosphor powder is sprayed onto the film to adhere to the exposed areas, and this exposure and spraying of the phosphor powder is carried out in three colors.Then, ammonia gas is applied to the photosensitive resin film to perform a fixing action, and the film is illuminated. The photosensitive resin in the areas where the body powder is attached is made insoluble in water, and the excess residue is washed out with an organic solvent to form a fluorescent surface. According to this method, the process is shortened because the process of forming the photosensitive resin film is completed once, and in addition, the phosphor powder is sprayed onto the film, and any particles that do not adhere to the film are blown off with air spray and collected. Since it can be reused in the same state, it has the advantage of being economically efficient.

However, even with this method, a fixing step using ammonia gas was still necessary.

The present invention has been made in view of these points, and its purpose is to provide a color picture tube that eliminates the conventional fixing process using ammonia gas, further shortens the process, and improves productivity. An object of the present invention is to provide a method for forming a fluorescent surface.

In order to achieve such an objective, the present invention
After adhering the phosphor powder to the sticky parts of the exposed area of the photosensitive resin film, it is treated with a solution containing an alkaline substance and an organic solvent to strengthen the adhesion of the phosphor. This is to remove excess residue.

The figures are cross-sectional views of a part of the face panel in each step of the method for forming the fluorescent surface of a color picture tube according to the present invention. First, a photosensitive resin mainly composed of diazonium salt is applied to the inner surface of the face panel 1 to form the film 2. Figure a shows this situation. A shadow mask is then used to expose the locations where the green phosphor is to be formed, converting the exposed locations into a sticky material. Next, when green phosphor powder is sprayed onto the surface of the film 2, the phosphor powder adheres only to the exposed areas having this adhesive property, forming a coating layer _3G . Further, by blowing away anything other than the adhered phosphor powder by air spraying, the phosphor powder is removed from the surface of the film 2 and recovered as it is. Thereafter, a coating layer _3B of blue phosphor powder and a coating layer _3R of red phosphor powder are respectively formed on the exposed areas in the same manner. Figure b shows this situation.

Next, when a solution containing an alkaline substance and _an organic solvent is poured onto the _inner surface of the face panel 1 as _shown in Fig. At the same time, the unexposed portions of the film 2 are washed and removed by the action of the organic solvent. Figure d shows this situation.

Next, a specific example applied to a 14-inch color picture tube will be described. PN,N dimethylaminobenzenediazonium salt zinc chloride 3wt%, alginate propylene glycol ester 0.6wt%,
Oxyethylene propylene block copolymer
A photosensitive aqueous solution consisting of 0.006Wt% and water 96Wt%,
It is coated on the inner surface of the face panel by spin coating to form a film having a uniform thickness of 0.5 μm, and then dried. Next, 18W/ ^m2 is applied from an ultra-high pressure mercury lamp through a shadow mask combined with the face panel.
The area of the film where the green phosphor is to be formed is exposed to light for 1 to 2 minutes at an intensity of . As a result of this exposure, diazonium decomposes in the exposed areas of the film to produce zinc chloride, which further adsorbs moisture in the air and becomes sticky. The atmosphere at this time had a temperature of 25±10℃,
A humidity of about 56±6% is appropriate. Next, spray the green phosphor powder onto the surface of the membrane, and then air spray the powder onto the exposed sticky part of the membrane.
Approximately 2.5 to 3 mg/cm ² is deposited to form a coating layer.
Thereafter, exposure and phosphor powder deposition operations are performed in the same manner to deposit blue and red phosphor powders in the form of dots or stripes. Next, ammonia water 1Wt%, ethyl alcohol 80Wt%, water 19Wt%
A strong phosphor film can be obtained by pouring an aqueous solution consisting of Since the phosphor film formed at a predetermined location in this way is strong, it will not come off even after thorough cleaning. This washing is sufficient to remove unwanted reactive products. Next, after wetting the fluorescent film with a polyvinyl alcohol aqueous solution,
A toluene solution of 3 to 3.5 Wt% isobutyl methacrylate resin is sprayed onto the face panel surface and dried to form a glossy film.Furthermore, a metal back aluminum film is vapor-deposited on top of this glossy film to form the fluorescent surface of the color picture tube. Form. When this color picture tube was operated, the color purity was improved due to sufficient cleaning, and the brightness of the fluorescent surface was increased by 5% due to the reduction of baking residue.

In the above embodiments, aqueous ammonia was used as the alkaline substance and ethyl alcohol was used as the organic solvent in the aqueous solution for treatment and cleaning, but sodium hydroxide as the alkaline substance and methyl alcohol, acetone, etc. as the organic solvent can also be used. For example, sodium hydroxide 1Wt%, methyl alcohol
80Wt%, water 19Wt% aqueous solution, ammonia water 1Wt
%, acetone 80 Wt%, and water 19 Wt% aqueous solutions also gave good results. Furthermore, the amount of alkaline substances is
If it is less than 0.1 Wt%, the fixing effect will not be sufficient, and if it is more than 2 Wt%, complex salts will form and dissolve the exposed areas of the film, resulting in a decrease in fixing performance. Therefore, it is preferable to use the alkaline substance in a range of 0.1 to 2 Wt%.

In addition to using only a phosphor, a pigment-attached phosphor can also be used to form the coating layer, and it is also possible to form a coating layer using only a pigment.

As described above, the color picture tube fluorescent surface forming method according to the present invention eliminates the need for the conventional fixing step using ammonia gas, shortens the work process and improves productivity. The resulting phosphor film becomes stronger, making it possible to perform sufficient cleaning, and this cleaning can sufficiently remove unnecessary reaction products, reducing residue after baking and improving brightness. There is an effect.

[Brief explanation of the drawing]

The figures are cross-sectional views of a part of the face panel in each step of the method for forming the fluorescent surface of a color picture tube according to the present invention. 1... face panel, 2... photosensitive resin film,
3 _G , 3 _B , 3 _R ...Coating layer.

Claims (1)

[Claims] 1. A photosensitive resin film mainly composed of diazonium salt is formed on the inner surface of a face panel, and predetermined areas of this photosensitive resin film are selectively exposed so that the exposed areas become sticky. In a color picture tube fluorescent surface forming method in which a phosphor powder is attached to an exposed area, the phosphor powder is attached to the exposed area and then treated with a solution containing an alkaline substance and an organic solvent. A method for forming a fluorescent surface of a color picture tube.