JPS6158134A - Formation of phosphor film - Google Patents

Abstract

PURPOSE:To obtain high quality phosphor film which does not show color mixing due to interference of color of light emitted by heating a substrate between the process where tackiness is reproduced by exposing photosensitive tacking layer on the substrate and the process where the phosphor material is supplied. CONSTITUTION:A photosensitive tacking layer 3 is formed at the internal surface 2a of bulb face 2 of substrate. The tackiness is reproduced to the exposing region 4 by exposing the desired region. Next, the photosensitive tacking layer 3 is a little heated from the lower surface of a bulb face 2 and tackiness of unwanted region is eliminated. Thereafter, the phosphor material powder 5 is supplied too the photosensitive tacking layer 3, it is adhered to the exposing region 4, the extra phophor material powder is eliminated and a phosphor material layer 5' corresponding to one color of emitted light. Thereafter, the phosphor material layer of the other colors of emitted light is formed by deviating the exposing region and a light absorbing material layer is formed to each phosphor material layer. This method is suitable for deposition and formation of phosphor film of cathode ray tube.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a fluorescent film, and particularly to a method for forming a fluorescent film for a cathode ray tube.

For example, the pulp (1) shown in FIG. 3 is used in the production of color television cathode ray tubes. A dry process method has been proposed as an example of a method for forming a fluorescent film on the inner surface of the face portion (2) of this pulp (1). The method for forming a fluorescent film using this dry process method will be explained in detail below with reference to FIGS. 4<a> to (C) and FIG. 5. First, as shown in FIG. A photosensitive adhesive that develops tackiness upon exposure to light is supplied to the inner surface (2a) of the valve face portion (2), and by rotating the pulp by an appropriate means, the centrifugal force of rotation causes the valve face portion (2) to become adhesive. ) A photosensitive adhesive layer (3) of uniform thickness is formed on the inner surface (2a) of the substrate. Furthermore, this photosensitive adhesive layer (3
) is heated and dried and applied to the inner surface (2a) of the valve face portion (2). Thereafter, as shown in FIG. 4(b), a desired portion of the photosensitive adhesive layer (3) is exposed to light to partially absorb moisture in the atmosphere within the pulp, and the exposed portion of the photosensitive adhesive layer (3) is The first step is to develop adhesiveness in the portion (4), and further, a phosphor powder (5) corresponding to one luminescent color, for example, red (R) is supplied, and the photosensitive adhesive layer (3) is formed.
A second step of adhering the phosphor powder (5) to the part (4) that has developed stickiness, and blowing away the remaining phosphor powder (5) on the inner surface (2a) of the bulb face part (2). As shown in FIG. 4(C), the phosphor N (5") corresponding to one luminescent color, that is, red (R), is removed through the third step of removing the luminescent material.
form. By sequentially repeating the above first to third steps for other luminescent colors, such as phosphor powders corresponding to green (G) and blue (B) and light absorbers such as graphite, different luminescent colors (R) can be obtained. G) Phosphor layer of (B) (5°') (5')
... and each phosphor layer (5°) (5")
A light absorber layer (6) (6) is formed in between, and the fixing and baking process finally produces different luminescent colors (R) (G) as shown in Figure 5. (B) Phosphor layer (5')
(5')...and light absorber! (6) (6)・-
A striped fluorescent film (7) consisting of... is formed on the inner surface (2a) of the bulb face portion (2). Each of the above light absorber layers (6)<6)-- is an adjacent phosphor layer (
5') It is formed with a predetermined width so that the emitted light colors of (5') do not interfere.

■ If the conventional method for forming a fluorescent film according to the procedure described above is carried out with the humidity atmosphere in the pulp set to, for example, about 80%, the photosensitive adhesive layer (3) is formed in the first step. ) is formed on the inner surface (2a) of the valve face portion (2) to develop adhesiveness in the exposed portion (4) of the photosensitive adhesive layer (3), as shown in FIG. The exposed area
.

The undesired part (4") which is the outside part (4), that is, the part where a light absorber layer is formed, or the part where a phosphor layer of another luminescent color is planned to be formed, and also the fluorescent part of the second color and subsequent colors. In the body layer forming process, moisture is adsorbed onto the phosphor layers of other luminescent colors that have already been formed, resulting in adhesiveness, and the second and third phosphor layers
In the step, the phosphor powder (5) adheres to the exposed portion (4) of the photosensitive adhesive layer (3) and also to the undesired portion. As a result, the stripe width (L
) becomes larger, that is, the adjacent light absorber layers (6) (6)
The phosphor layer (5') extends to the area where ・-・-・ is planned to be formed.
(5')... is formed slightly, so the light absorber N (
6) (6) - The stripe width (β) (β) - becomes smaller, and the adjacent phosphor layers (5') (5')
There is a problem that the emitted colors of - and - interfere with each other and cause color mixing when viewed from the entire phosphor film (7), or that phosphors with different emission colors coexist in the same layer, resulting in color mixing. Ta. In order to solve this problem, it is necessary to prepare the inside of the bulb to prevent adhesion due to moisture adsorption on the unwanted portions of the photosensitive adhesive layer (3) or on the already formed phosphor layer. The humidity atmosphere must be strictly controlled, for example, it is said that it is necessary to set the above humidity to a condition of 55 ± 6%, but in this case, it is necessary to increase the size of the equipment to strictly set the above humidity conditions. There is an unavoidable problem that humidity management is complicated.

The present invention has been proposed in view of the above-mentioned problems, and its specific means is to expose a desired portion of a substrate on which a photosensitive adhesive layer is formed, and expose the photosensitive adhesive layer to light. a first step of developing tackiness in the exposed portion; a second step of supplying a phosphor or a light absorber onto the substrate and adhering it to the tackiness-developed portion of the photosensitive adhesive layer; A method of forming a fluorescent film on a substrate by repeating the above steps while shifting the exposed area corresponding to phosphors of different emission colors, including a third step of removing the remaining phosphor on the substrate. In this step, prior to the second step, the substrate is coated with water in the exposed portion of the photosensitive adhesive layer without losing adhesion, and the unexposed portion and the portion above the already formed phosphor layer. It is characterized in that it is heated at a temperature that causes the moisture to scatter.

An embodiment in which the method for forming a fluorescent film according to the present invention is applied to the production of cathode rays for a color television, as in the conventional case, will be described below with reference to FIGS. 1 and 2. The same reference numerals as in FIG. 6 indicate the same parts, and the explanation thereof will be omitted. The feature of the present invention is that between the first step and the second step, a photosensitive adhesive layer (3
) is heated under predetermined processing conditions.

First, in the conventional manner, the inner surface (2a
) is coated with a photosensitive adhesive layer (3). Thereafter, in a first step, the inner surface (2a
) is exposed to light to absorb moisture in the atmosphere inside the bulb, and the exposed portion (4) of the photosensitive adhesive layer (3) develops tackiness. At this time, the atmosphere inside the bulb and the humidity therein are maintained within the range of 40 to 80%. As a result, the inner surface of the valve face portion (2) (
The desired part of 2a), that is, the exposed part (4) of the photosensitive adhesive M (3) develops tackiness, and at the same time, the undesired part (4") which is the outer part of the exposed part (4) or other In the area where the phosphor of the second color is to be formed, and in the phosphor layer formation process for the second and subsequent colors, the phosphor layers of the other colors that have already been formed also become moist, albeit slightly. Therefore, after the first process, the valve face part (2
) Heat the photosensitive adhesive layer (3) slightly from the bottom surface. At this time, for example, in the case of a 1 to 3 inch bulb, the heating temperature should be set to 50
When the heating time at ~100°C is set to 1 to 3 minutes and the above heat treatment is performed under these setting conditions, the exposed portion (4) of the photophobic viscous N layer (3) and the undesired portion adjacent thereto. Moisture scatters from the 1. At the time when the moisture in the undesired areas disappears, a sufficient amount of moisture remains in the exposed areas (4) for the phosphor powder to be described later to adhere thereto. In other words, the photosensitive adhesive layer (3
) The undesired parts of the adhesive layer (3) lose their adhesiveness, but the exposed parts (4) of the photosensitive adhesive layer (3) contain moisture containing hygroscopic substances, and this moisture is difficult to scatter when heated. Therefore, it remains tacky enough for the phosphor powder to adhere to it. Thereafter, a phosphor powder (5) corresponding to one emitting color, for example red (R), is applied to the photosensitive adhesive layer (3) in a conventional manner.
A second step of supplying and adhering the photosensitive adhesive m (3) to the exposed portion (4), and a third step of removing the remaining phosphor powder (5) produce one luminescent color, red. A phosphor layer (5°) corresponding to (R) is formed. By sequentially repeating the above steps for other luminescent colors, green (G), blue (B) phosphor powders, and light absorbers such as graphite, different luminescent colors (R
) (G) (B) phosphor layer (5") (5')...
At the same time, each phosphor layer (5') (5')
A light absorber N (6) (6)... is formed between -, and the fixing and baking process is followed to finally form a striped fluorescent film (7) on the bulb face part (2). Adhesion is formed on the inner surface (2a).

The heating temperature and heating time when heating the valve face part (2) are set depending on the inch size of the valve, that is, the thickness of the valve face part (2). The conditions are set as described above, and when changing the setting conditions, the valve face part (after the heat treatment of 2j, the photosensitive adhesive layer (3)
The moisture in the undesired areas of the photosensitive adhesive N(3) is sufficiently removed to make it non-adhesive, and the exposed areas of the photosensitive adhesive N(3) (
The above conditions may be selected within a range that allows the moisture in step 4) to remain and maintains sufficient tackiness for the phosphor powder (5) to adhere.

In the above embodiment, a method of forming a striped fluorescent film on the inner surface of a bulb face part in the manufacture of a color television cathode ray tube was explained, but the present invention is not limited to this. Of course, the present invention can be applied to a method for forming a fluorescent film.

According to the present invention, since the substrate is heated between the first step and the second step, the phosphor does not adhere to undesired portions on the substrate. Color mixing due to interference of the emitted light colors of the phosphors is eliminated, and a good fluorescent film can be obtained. As a result, there is no need to strictly control the humidity in the atmosphere, so it is possible to downsize the equipment and the humidity can be easily controlled.

[Brief explanation of drawings]

1 and 2 are partially enlarged sectional views showing a substrate (bulb face portion) for explaining an embodiment of the fluorescent film forming method according to the present invention, and FIG. 3 is a partially enlarged sectional view showing a substrate used for manufacturing a cathode ray tube. Partial cross-sectional view showing −□□□j of the pulp to be processed, FIG. 4(a)
- (c) are cross-sectional views showing the substrate (bulb face part) for explaining each step in a conventional method for forming a fluorescent film using a dry process method, and Fig. 5 shows a fluorescent film formed on the substrate. A partial plan view showing an example of the above, Fig. 6 is Fig. 4 (C)
FIG. (2)・−・−・Board (valve face part), (3)・
--- Photosensitive adhesive layer, (4) --- Desired portion, (5)
−・fluorescent material, (6)・−・light absorber, (7) −・
Fluorescent film.

Claims (1)

[Claims] (1) A first step in which a desired portion of the substrate on which the photosensitive adhesive layer is formed is exposed to light to develop adhesiveness in the exposed portion of the photosensitive adhesive layer, and a phosphor or light absorber is placed on the substrate. supply,
A second step of adhering the above-mentioned photosensitive adhesive layer to the adhesive part, and a third step of removing the remaining phosphor on the substrate. A method for forming a fluorescent film on a substrate by repeating the above steps while shifting the exposed portion, the method comprising heating the substrate prior to the second step.