JPS6227496B2 - - 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 to prevent mixing of color elements, particularly different color pigments, on the fluorescent surface of a color picture tube.

Conventionally, the phosphor surface of a color picture tube is coated with phosphors that emit light equivalent to the three primary colors in the form of dots or stripes, then an organic coating is applied in a so-called filming process, and then a reflective material such as aluminum is coated on the phosphor surface of the color picture tube. It is formed by vapor-depositing a metal reflective film with good quality, and then proceeding to subsequent steps such as baking. In this case, the organic film is applied not only on the dots or stripes of the phosphor but also in the gaps between the dots or stripes, and if the organic film is thick, a large amount of organic decomposition gas will be generated during baking, which will cause the metal film This can cause many problems in the process, such as swelling or peeling, and if the organic coating is too thin, pinholes or cracks may prevent a highly reflective metal surface from being obtained. have.

Furthermore, in recent color picture tubes, inorganic pigments of the same color as the luminescent color of the phosphor are added to the phosphor dots in order to reduce the reflectance of external light on the phosphor surface and improve image contrast under external light. Alternatively, a method of adding it in stripes is used. In this case, the method of mixing the pigment into the phosphor slurry is as follows:
Although the process is simple, there is a problem in that pigments of the same color as the phosphor applied later will adhere to the dots or stripes of other colors that have already been formed, reducing brightness. The method of using a so-called pigmented phosphor, in which the pigment is preliminarily fixed to the phosphor with an adhesive, is not economical because the pigment peels off during use of the slurry, and a lengthy process for attaching the pigment to the phosphor is required. There are problems such as a heavy burden on people.

It is an object of the present invention to simultaneously solve the problems associated with the use of filming and pigmented phosphor in the conventional method of forming a phosphor surface of a color picture tube.

In order to achieve the above object, in the present invention,
After coating the phosphor slurry and before drying, a thin film of an organic material that is transparent and hardens upon exposure was formed on the surface of the slurry film, and then operations such as drying, exposure, and development were performed. In this way, each dot or stripe of the phosphor formed by the above operations is coated with an organic film of the same shape and area as the dot or stripe on its surface (electron gun side). It turns out. Therefore, even if a phosphor slurry of another color is applied after forming dots or stripes of phosphor of one color, the dots or stripes of phosphor will be covered with the same shape by the exposure. Since a solidified organic film exists in the same area, no different color pigments are mixed in. Furthermore, the organic film exists only on the surface of the dots or stripes of the phosphor, and does not exist in areas that are not effective in reflecting the phosphor's light, such as the gaps between the dots and stripes. When a metal reflective film is deposited on such a surface, a flat, continuous metal reflective film with good reflection efficiency is formed at the locations where the organic film is present on the phosphor dots or striped surface, but it is not possible to For example, the metal film on the side surface of the periphery of the dots or stripes of the phosphor has many discontinuous parts that act as holes for organic decomposed gas because there is no underlying organic film attached. The metal reflective film does not swell at all due to the release of organic matter decomposition gas during baking.

This will be explained in more detail below. That is, the slurry of the first color mixed with pigment is applied by spin coating using a well-known method, but when the panel is rotated and the excess slurry is sufficiently shaken off to reach the desired film thickness, it is still difficult to apply the slurry to the gaps between the light particles. has trapped water, creating a free surface for water. In this state, a solution containing a water-soluble polymer substance and a substance that crosslinks polymers by UV irradiation is applied to the entire fluorescent surface in an organic solvent that is immiscible with water and has a lower surface tension than water. It is applied in the form of a mist with a gentle spray, spread over the free surface of the water, forming a continuous organic film on the aqueous phase, and then dried and fixed. After that, when a shadow mask or aperture grill is attached and UV exposure is performed using a well-known method, not only the organic coating but also the underlying phosphor layer is exposed to the ultraviolet rays that have passed through the organic coating in the UV irradiated area. Becomes insoluble in water. When development is carried out with water or hot water, the organic film in the unexposed areas is a water-soluble polymeric material and is eluted together with the underlying phosphor film to form the desired dot or stripe pattern. The dots or stripes formed in this manner are characterized by having an organic coating on their upper surface (electron gun side). Next, when a slurry of a second color mixed with a pigment is applied by spin in the same way, the phosphor and pigment will spread over the dots or stripes of the first color, but because of the organic film, the fine pigment will be spread over the dots or stripes of the first color. It does not penetrate into the interior of the organic film and remains only on the organic film. Therefore, if development is performed through the same steps as for the first color, not only the excess phosphor in the unexposed areas but also the pigment will be washed away, and no mixed colors will remain. For the second color, an organic film is formed on the dots or stripes of the phosphor using the same procedure as for the first color, so when applying the phosphor slurry for the third color, the pigment is 1. 2nd
Does not adhere to colored phosphor dots or stripes and is washed away. The third color phosphor dots or stripes also have an organic coating on them, so all three phosphor dots or stripes have their top covered with an organic coating. It turns out. As a result, these organic coatings can also be used as a film when depositing a metal reflective film, so that aluminum vapor deposition can be performed immediately after coating the three colors. These organic films are not present in the gaps between the phosphor dots or stripes, so when they are decomposed and removed by baking,
In addition to the small amount of organic matter, it is difficult to form a continuous aluminum film on the edge portions of the dots or stripes that are unrelated to effective light emission, resulting in the formation of many holes for organic matter decomposition gas.
No blistering occurs, and a uniform, flat, continuous aluminum film is formed only on the surface that is effective for reflection.

Examples will be described below.

A green phosphor slurry (without pigments) consisting of a green-emitting phosphor, polyvinyl alcohol, ammonium dichromate, a surfactant, and an appropriate amount of water is evenly spread on the inner surface of the panel by spin coating, and then the following is applied. A film forming solution having the composition is applied in the following manner.

Film forming liquid Polymer substance Polyvinyl ether 3 parts Organic solvent Butyl acetate 96 parts Photosensitive agent Disulfonyl azide 1 part Application method Spray the film forming liquid in the form of a mist using a mist generator (nebulizer), and apply it to the panel in the atmosphere. Expose your inner self. Or you can use a gentle spray.

Immediately after application, dry to fix the fluorescent film. Next, the film is exposed to light using a prescribed method, first developed with pure water at 30°C or lower, then developed with warm water at 40°C to form a dot or stripe image, and dried. This completes the formation of green phosphor dots or stripes.Next, a blue phosphor slurry having almost the same composition as the green case, except for the phosphor emission color and pigment, is spin-coated to give a green phosphor dot or stripe. An organic film is formed in the same way as in the case of green color, and then the same steps as in the case of green color are carried out. After repeating the same operation for the red phosphor slurry (containing red pigment), an aluminum reflective film is immediately formed on the phosphor film on the inner surface of the panel by vapor deposition, without going through the conventional filming process. .

As explained above, according to the present invention, a pigmented fluorescent surface of a color picture tube can be formed extremely easily without mixing different color pigments, and color mixing can be prevented even in the case of a color picture tube without the addition of pigments. Moreover, there is no need for a special filming process as in the conventional method, and a good metal reflective film can be deposited.

Claims (1)

[Claims] 1. In a method for forming a phosphor surface of a color picture tube, a thin film of an organic substance that is translucent and reacts and solidifies upon exposure is formed on the surface of the slurry film after applying a pigment-coated phosphor slurry and before drying, and then drying. The process of performing various operations necessary to form phosphor dots or stripes, such as exposure and development, is repeated for each color to form phosphor dots or stripes of each color, and a transparent material that has been reacted and solidified by exposure is applied only to the upper surface of each color. 1. A method for forming a fluorescent surface of a color picture tube, which comprises forming a thin film layer of a photosensitive organic substance, and then forming a metal reflective film on at least the thin film layer without intervening any other member.