JPS60230337A - Formation of fluorescent film - Google Patents

Abstract

PURPOSE:To form a fluorescent film whose thickness can be maintained constant by supplying moistened air into the bulb during exposure of a photosensitive adhesive material. CONSTITUTION:First, a photosensitive adhesive substance (P) is applied to the inner surface of a bulb face 1a, then dried. Next, after a pattern mask not indicated in the figure is placed on the outer surface of the bulb face 1a, the adhesive substance (P) is specifically exposed by an exposure source installed outside a bulb 1 and not indicated in the figure. During the exposure, a gas with a humidity of abut 20-50% is sprayed over the adhesive substance (P), so that only desired areas of the adhesive substance (P) are exposed. Next, decomposition gas produced by exposure is removed by operating an air supply device 2 and the moisture of the air is caused to be absorbed by the exposed areas to make then adhesive. Next, after the bulb 1 is removed, a red phosphor powder is sprayed over the inner surface of the face 1a to fix the powder only to desired areas of the adhesive substance (P). After that, surplus phosphor powder is blown off and removed, thereby forming a fluorescent film.

Description

[Detailed Description of the Invention] Industrial Summer Machine Friendship! The present invention relates to a method for forming a fluorescent film, and more particularly to a method for forming a fluorescent film on the inner surface of a bulb face in the manufacture of cathode ray tubes such as color picture tubes.

Conventionally, a fluorescent film is generally formed on the inner surface of the bulb face of a cathode ray tube by using various methods such as precipitation and screen printing. As an example of the formation method, a fluorescent film formation method (dry process method) disclosed in, for example, Japanese Patent Laid-Open No. 56-38732 has been proposed. The method for forming a fluorescent film will be described below. First, the bulb face is fixed at a predetermined position, and a photosensitive adhesive substance that becomes sticky when exposed to light is applied to the inner surface of the bulb face.

After drying the photosensitive adhesive material, the photosensitive adhesive material is selectively exposed to light to absorb moisture in the air and develop adhesiveness only in desired areas.

Then, by spraying the phosphor powder onto the photosensitive adhesive material, the phosphor powder is applied only to the areas that have developed tackiness, and then the excess phosphor powder is removed by blowing away.
The fixing and baking processes form a fluorescent film on the inner surface of the bulb face portion.

For example, in the case of manufacturing cathode ray tubes for color televisions, a flat panel face portion (1a) shown in FIG. 3 is used, and the above steps are repeated multiple times for phosphor powders of different luminescent colors on the inner surface. That is, after the process of applying the photosensitive adhesive substance to the inner surface of the bulb face, each subsequent process, such as the exposure process, corresponds to different emitted colors, for example, red (R), green (G), and blue (B). The above series of steps is repeated for each phosphor powder. As a result, as shown in FIG. 2, fluorescent films of different emission colors (R), (G), and (B) are formed in a predetermined pattern on the inner surface of the bulb face portion.

One point: The conventional method of forming a phosphor film according to the above procedure is simple and easy to perform, and since the phosphor powder used is a single substance, as mentioned above, it is unnecessary to use it as an extra material. There is an advantage that the recovered phosphor powder can be used again and the utilization rate of the phosphor powder is high.

However, the valve shown in Fig. 4, which has a face part (la), funnel part (1b), and neck part (1c) integrated (
1), the air inside the valve (1) hardly moves to the outside, and the decomposed gas is generated in the valve (1) every time the photosensitive adhesive material is exposed. There was a problem in that the thickness of the fluorescent film was inconsistent due to the deterioration of the sensitivity of the photosensitive adhesive material due to gas filling.

The present invention includes a step of applying a photosensitive adhesive substance to the inner surface of the valve face portion, a step of selectively exposing the photosensitive adhesive substance on the inner surface of the valve face portion after drying to develop tackiness,
The method includes the step of applying phosphor powder to the sticky part of the photosensitive adhesive substance to form a phosphor film, and repeating this process multiple times for different luminescent colors of phosphor powder. This is a fluorescent film forming method in which air containing moisture is supplied into a bulb in the step of exposing the photosensitive adhesive material.

An embodiment of the fluorescent film forming method according to the present invention will be described below. FIG. 1 shows a specific means for supplying air containing moisture to the inside of a bulb positioned at a predetermined position during the exposure process. In the figure, (1) is a valve positioned and fixed with the neck (lc) facing down, and (2) is the valve (
For example, a water pump is used as the air supply device installed in the transport line of '1). (2b) is the air supply pump (2
(2C) is an air supply nozzle that guides constant temperature air from the air supply pump (2a) into the valve (1).

First, a photosensitive adhesive substance (P) that becomes adhesive when exposed to light is applied to the inner surface of the valve face portion (1a). After this coating step, the photosensitive adhesive substance (P) is dried, the bulb (1) is placed as shown in FIG. 1, a pattern mask (not shown) is placed on the outer surface of the face, and the bulb (1) )
The photosensitive adhesive material (P) is selectively exposed to light by an external light source (not shown). At this time, the photosensitive adhesive substance (P) has a humidity of 1
A gas with a humidity of 0 to 60%, preferably 20 to 50% is blown. In this way, only the desired part of the photosensitive adhesive substance (P) is exposed, and then the air supply device (2) is activated to remove the decomposed gas generated by the exposure, prevent a decrease in sensitivity, and prevent it from entering the air. The moisture contained in the film is absorbed by the exposed areas, creating tackiness. Thereafter, the bulb (1) is taken out, and phosphor powder of a certain luminescent color, for example, red (R) is sprayed on the inner surface of the face portion (1a) onto the photosensitive adhesive material (P), thereby creating a desired adhesive property. Apply the powder to the inner surface of the bulb face (1a), and then remove the excess phosphor powder by blowing it away.
Forms a fluorescent film. Thereafter, a pattern mask is placed on the outer surface of the face section at a predetermined pitch shifted from the initial position, exposed, and the above operation is repeated for different emitted colors.

According to the present invention, decomposed gas generated inside the bulb during the exposure process is discharged to the outside of the bulb by supplying air containing moisture into the bulb during the exposure process, thereby creating an atmosphere for the photosensitive adhesive. Conditions can be maintained uniformly, and the photodecomposition rate (sensitivity) of photosensitive adhesive substances does not decrease due to exposure to light.
It is possible to prevent uneven adhesion of the phosphor powder and maintain a constant thickness of the phosphor film, resulting in a product of good quality.

[Brief explanation of the drawing]

FIG. 1 is a schematic partial cross-sectional view showing the exposure process according to the present invention;
Fig. 2 is a partial plan view showing the inner surface of the bulb face in which fluorescent films of different emission colors are formed in a predetermined pattern, Fig. 3 is a cross-sectional view showing an example of a flat panel-shaped bulb face, and Fig. 4 is FIG. 2 is a sectional view showing a valve in which a face portion, a funnel portion, and a neck portion are integrated. (1)---Valve, (1aL-valve face part, (
2) - Air supply device, (P) - Photosensitive adhesive substance. Fist jvJ 1α 1B4 Figure x B

Claims (1)

[Claims] (1) A step of applying a photosensitive adhesive substance to the inner surface of the valve face portion; a step of selectively exposing the photosensitive adhesive substance on the inner surface of the valve face portion after drying to a phosphorescence to develop adhesiveness;
a step of applying phosphor powder to the sticky part of the photosensitive adhesive substance to form a phosphor film, the formation being repeated multiple times for phosphor powders of different luminescent colors; A method for forming a fluorescent film, characterized in that in the step of exposing the photosensitive adhesive material, air containing moisture is supplied into the bulb.