JPS6019100B2 - Method for forming light absorption region of color cathode ray tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of forming a light absorption region of a color cathode ray tube.

Color cathode ray tubes are designed to prevent the contrast of the screen from decreasing due to the reflection of external light by disposing a light absorbing part on the light body that forms the light surface and emits red, green, and blue light. It is configured.

This crab light surface S is, for example, as shown in FIGS. 1 and 2,
On the inner surface of the face plate 1 of the cathode ray tube, crab dots R, G, and B that emit red, green, and blue light are adhered in a predetermined arrangement relationship, and light absorption occurs between the crab dots. A light absorbing layer 2 coated with black paint is arranged and formed. Then, an electron beam corresponding to each color light is emitted from an electron gun (not shown) placed in the neck of the cathode ray tube facing the crab light surface S, and the electron beam reaches a predetermined position on the crab light surface S. A positioning electrode, for example a shadow mask 3, is arranged. The electron beam that arrives on the figure light surface S through this shadow mask 3 is slightly larger than each crab light dot R, G, and B on this crab light surface S, as shown by the dotted line in FIG. The size of each beam, the size of the aperture of the shadow mask 3, etc. are selected so that the landing spot becomes a certain landing spot. By doing this, even if a positional shift occurs within the range of the corresponding beams, each of the crab light dots R, G, and B can be reliably emitted, and the light bodies of other colors can be emitted. In other words, the light absorption layer 2 is designed to prevent the beam from emitting light, that is, to have a landing margin for the beam, and also to prevent the external light arriving here from being reflected and observed by the observer due to the presence of the light absorption layer 2. However, it is designed to avoid a decrease in the contrast of the video screen due to the reflection of this external light. In order to obtain a color crab light surface constructed as described above, each crab light body is mixed with a photosensitive agent and applied as a mask, for example, by a shadow mask itself, by the so-called optical masking method of ordinary photographic technology. However, since the black layer, that is, the light-absorbing layer, has a light-blocking property, even if a photosensitive agent is mixed therein, the black layer can be coated in a predetermined pattern with high precision. The disadvantage is that it cannot be competed with.

Therefore, the present invention is to apply a light-absorbing material having a light-blocking property to the inner surface of the face plate using an indirect optical method, and to form the light-absorbing material layer into a predetermined pattern with high precision. The present invention aims to provide a method for forming a light absorption region of a color cathode ray tube.

An embodiment of the present invention will be described below with reference to FIG. 3. In the present invention, for example, a negative photosensitive agent layer 4 is coated on the inner surface of the face plate 1 (FIG. 3A).

As this photosensitive agent 4, well-known photosensitive agents can be used, but
It is required that the photosensitive agent dissipates and disappears during baking treatment or that its adhesive strength to the face plate 1 decreases, and examples of such a photosensitive agent include PVA (polyvinyl alcohol) with ammonia dichromate added thereto. Tie it up using a photosensitive agent consisting of: Thereafter, for example, an electrode for determining the arrival position of the mother and child beams, such as a shadow mask 3, is placed in the face plate 1 at the same position as that in the final cathode ray tube.

Then, using this shadow mask 3 as a mask, all the areas to be coated with red, green, and blue light are exposed to light, and the areas other than those that should finally become the light absorbing layer 2, in other words, the areas where each color light is applied are exposed. Exposure and harden the area where the halo is to be painted. Next, the shadow mask 3 is removed from the face plate 1, and the photosensitive agent 4 is developed, leaving behind the photosensitive agent layer 4 in the area a, which is exposed and hardened and is to be finally coated with the crab photons of each color. , the other part b is removed (FIG. 3B).

A light-absorbing material 2 is applied almost entirely onto the inner surface of the face plate 1 from above the remaining photosensitive agent layer 4a (FIG. 3C).

As the light-absorbing material 2, a material that can withstand the heat during baking and is water resistant, such as a pigment made by mixing a binder such as water glass, aluminum forkate, or aluminum phosphate into powdered carbon powder, can be used. . Next, a baking treatment is performed.

This baking treatment is carried out at a temperature of, for example, 45,030°C to make the light-absorbing material layer 2 exhibit adhesion to the face plate, and also to cause the photosensitive agent layer 4a to dissipate and disappear (FIG. 3D), or The adhesive force of this photosensitive agent layer 4a to the face plate 1 is reduced. Thereafter, the face plate 1 is placed on a rotary table 5 and rotated at an appropriate speed while spraying water onto the surface of the light absorbing material layer 2 with a spray gun 6 to make moisture adhere to it (see Fig. 3). E).

Next, the light-absorbing material layer 2 is developed to remove the photo-sensitive material layer 4a, thereby removing the light-absorbing material layer 2a floating from the face plate 1 or the photo-sensitive material layer 4 with reduced adhesive strength.
The light-absorbing material layer 2a formed above a is cleaned by injecting, for example, hydrogen peroxide and Nigen 2 water (Fig. 3F).
. In this way, the light-absorbing material layer 2b is formed only on the portion a of the face plate 1 to which the crab phosphor is to be applied.

After completing the above steps, the crab light surfaces R, G, and B of each color are sequentially printed through the usual steps to obtain the shark light surface S shown in FIG. 2 (FIG. 3G).

When cleaning the light-absorbing material layer 2a to be removed in the above process, water is applied to the light-absorbing material layer 2a in advance, so the surface becomes moist and hydrogen peroxide (as washing water) 502) Water becomes easier to absorb and flows through the light-absorbing material layer 2a in a uniform manner without causing uneven water flow or peeling off the light-absorbing material layer 2b in necessary parts. Cleaning is carried out.

In addition, even if the water attached to the light-absorbing material layer 2a condenses into water droplets and forms a water film, when hydrogen peroxide (ratio 02) water is injected, this water film acts as a buffer for the impact force of the water injection. This will prevent uneven marks from occurring. In order to spray water onto the light-absorbing material layer 2a in this way, the best method is to use a spray gun 6 as shown in FIG. Place 200 [/min] of pure water at an air pressure of 2 to 4k9
It is desirable that the force of the equidistant fog that is sprayed by the pressure of the /c flow be as small as possible, and that it be as fine as water droplets. As described above, according to the method of the present invention, a light-absorbing layer is formed on a face plate using a photosensitive agent layer formed by an optical method, that is, a photographic method, which is suitable for forming delicate putters with high precision. Therefore, this light absorption layer is equivalent to being indirectly formed by a photographic method, and therefore, it can be reliably formed into a fine pattern.

Furthermore, according to the method of the present invention described above, the surface of the light-absorbing material layer is exposed to water before washing with hydrogen peroxide (ratio 02) water or the like to remove the remaining photosensitive material and the light-absorbing material layer thereon. When washing with hydrogen peroxide (ratio 02) water, etc., the washing water uniformly penetrates the light-absorbing material layer to be washed, and flows only in one part, resulting in uneven running water marks. There is no fear that the light-absorbing material layer will peel off in necessary parts, the light-absorbing material layer can be reliably formed, the light-absorbing region and the light-emitting region can be formed separately with high precision, and the contrast of the screen can be improved. This significantly improves the image quality and provides a clear screen.

In the above example, a case was explained in which a shadow mask was used as an electrode for determining the electron beam arrival position. A similar effect can be obtained by applying the present invention to a cathode ray tube whose surface is formed by vertically extending light strips, and a light absorbing portion is arranged between each strip. As a photosensitive agent, not only a negative type but also a positive type can be used.When using a positive photosensitive agent, the position of the light source must be set at a predetermined position for the exposure process. By moving the pitch in the horizontal direction, the area other than the area to be painted with the crab light of each color light is finally exposed.

[Brief explanation of the drawing]

1 and 2 are a sectional view of a color cathode ray tube and an enlarged front view of a light surface for explaining the method of the present invention, and FIG. 3 is a process diagram showing an embodiment of the method of the present invention. . In the figure, 1 is a face plate, 2 is a light absorbing material layer, 4 is a photosensitive agent layer, and 6 is a spray gun. Figure 3 Figure 1 Figure 2

Claims (1)

[Claims] 1. A process of applying a photosensitive agent to the inner surface of the fae plate of a cathode ray tube, and after exposing the photosensitive agent layer in a predetermined pattern, applying a photosensitive agent corresponding to a portion where a light absorption layer is to be formed based on the predetermined pattern. a step of removing the layer, a step of applying a light-absorbing material to the entire inner surface of the panel, a step of spraying water onto the surface of the light-absorbing material layer, and a step of applying a solution to dissolve the remaining photosensitive material to the light-absorbing material layer. A method for forming a light absorbing region of a color cathode ray tube, which comprises the step of removing a residual photosensitive material and a light absorbing material layer thereon.