JPH04138639A - Phosphor screen forming method - Google Patents

Abstract

PURPOSE:To improve brightness of a phosphor screen by forming an organic film after a hardened film of sensitive resin is formed in a central part of a phosphor picture element. CONSTITUTION:A black matrix film 12 and a phosphor picture element 13 are formed in an internal surface of a panel 11. Next, sensitizing liquid, formed of 1.0 to 5.0% polyvinyl alcohol and 0.1 to 5.0% dichromate, is applied to form a coating film 14. Then, the film 14 is exposed for a short time through a shadow mask 15 and developed to form a hardened film 14a of polyvinyl alcohol and ammonium dichromate in only a central part of the phosphor picture screen 13. An organic film 16 and a metal evaporation film 17 are formed by applying acrylic system emulsion, to remove an organic component by baking. In this way, a stable phosphor screen of high brightness can be formed without generating inferiority of swelling and exfoliation in the metal evaporation film 17.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a phosphor screen of a cathode ray tube, and more particularly to a method for forming an organic coating layer via a phosphor layer and a metal vapor deposition layer.

In the conventional phosphor screen of a Q1-folding cathode ray tube, a metal vapor deposited film is formed on the phosphor pixels via an acrylic organic coating, thereby making the metal vapor deposit film close to a mirror surface and improving the brightness of the phosphor screen.

FIG. 2 is a schematic diagram showing the formation flow of this type of acrylic organic film. Phosphor pixels 3 are formed in the openings of the black matrix film 2 on the inner surface of the panel 1 (see FIG. 2A), and the fluorescent An acrylic resin emulsion is applied directly onto the body pixels 3 and heated and melted to form an acrylic organic coating 6 (see FIG. 2E). Next, a metal vapor deposition film 7 is formed on this organic film 6 (see FIG. 2F), and finally, the organic film 6 is removed by firing (see FIG. 2G).

However, according to the above method, since the acrylic emulsion easily penetrates between the phosphors, the irregularities of the phosphors appear as they are in the organic coating, and a sufficiently smooth metal vapor deposited film cannot be obtained. Furthermore, when a base film is formed to cover the unevenness of the phosphor, the smoothness of the organic film becomes too high, which causes the metal vapor deposited film to blister or peel off when fired.

Therefore, this invention was proposed to solve the above problem, and aims to provide a method for forming an organic film that can improve the brightness of a phosphor screen without causing blistering or peeling of the metal vapor deposited film. .

In order to solve the above problems, this invention applies a photosensitive resin liquid onto the phosphor pixels formed on the inner surface of the panel, exposes only a predetermined portion of this coating film, and develops it to form a cured film.

That is, after exposing the phosphor pixel portion weakly to light through a shadow mask, a cured film of photosensitive resin is formed only in the center of the phosphor pixel by development, and an acrylic emulsion is applied on top of this. Disclosed is a method for forming a phosphor screen of a cathode ray tube, which is characterized by forming an organic film.

Specifically, polyvinyl alcohol and ammonium dichromate are used as the photosensitive resin liquid, and the respective concentrations are selected within the ranges of 1.0 to 5.0% and 0.1 to 5.0%.

1. According to the above method, a cured film of photosensitive resin is formed only in the central part of the phosphor pixel, and the unevenness of the phosphor is alleviated, but the unevenness of the phosphor remains as it is in the peripheral part of the phosphor pixel. A highly smooth organic film can be formed only in the center of the phosphor pixel. As a result, a metal vapor deposition film that is closer to a mirror surface is formed in the center of the phosphor pixel, improving the brightness of the phosphor screen, while the metal vapor deposition film around the phosphor pixel has pores and connections caused by the phosphor. In addition, the metal vapor deposited film does not swell or peel due to firing.

Soho doctor The present invention will be explained below with reference to the drawings.

FIG. 1 is a schematic sectional view showing an embodiment of the present invention.

According to the figure, a step (A) of forming a black matrix film 12 and a phosphor pixel 13 on the inner surface of the panel 11;
0-5.0% polyvinyl alcohol and 0.1-5.0%
% dichromic acid to form the coating film 14 (B), a step (C) of exposing for a short time through the shadow mask 15, and developing this to form the coating film 14 at the center of the phosphor pixel 13. Step (D) of forming a cured film 14a of polyvinyl alcohol and ammonium dichromate only on
), a step (E) of applying an acrylic emulsion to form an organic film 16, and a step (E) of forming a metal vapor deposition film 17 (
F), and a step (G) of removing the residual material by firing. According to the above configuration, the cured film 14a formed only in the central part of the phosphor pixel 13 allows the metal vapor deposited film 17 with high smoothness to be obtained in this part, and the phosphor pixel 13
Appropriate pores and connections are formed in the metal vapor deposited film 17 due to the unevenness of the phosphor in the peripheral area. Therefore, a stable phosphor screen with high brightness can be formed without causing defects such as blistering or peeling in the metal vapor deposited film 17.

As explained above, this invention forms a cured film of photosensitive resin at the center of the phosphor pixel, and then forms an organic film, so that only the center of the phosphor pixel has high smoothness. Since a metal vapor deposited film having appropriate pores and connections is formed in the peripheral area, a high brightness phosphor screen can be formed without causing blistering or peeling defects in the metal vapor deposited film during firing.

[Brief explanation of the drawing]

FIG. 1 is a schematic flow diagram of a method for forming a phosphor screen according to an embodiment of the present invention, and FIG. 2 is a schematic flow diagram of a conventional method for forming a phosphor screen. 11...Panel, 12...Black matrix film, 13...
... Phosphor pixel, 14 ... Photosensitive resin coating film, 15 ... Mask, 16 ... Organic film, 17 ... Vapor deposition film. ``Kazuku Ako B'' Low ○

Claims (3)

[Claims] (1) A step of forming a phosphor pixel on the inner surface of the panel via a shadow mask, a step of forming an organic film covering the phosphor pixel, a step of forming a metal vapor deposition film on the organic film, and a step of forming the organic film on the organic film. In a method for forming a phosphor screen of a cathode ray tube, which includes a step of removing the coating by baking, prior to forming the organic coating, a photosensitive resin is applied, exposed through a shadow mask, and unexposed areas are developed, and the phosphor is removed. A method for forming a phosphor screen characterized by forming a cured film in the center of a pixel. (2) The method for forming a phosphor screen according to claim 1, wherein the photosensitive resin is polyvinyl alcohol and ammonium dichromate. (3) The concentration of the polyvinyl alcohol is 1.0 to 5.
0%, ammonium dichromate concentration 0.1-5.0
%. The method for forming a phosphor screen according to claim 2.