JPH02247954A - Filming material for fluorescent screen of cathode-ray tube - Google Patents

Abstract

PURPOSE:To make it possible to from a metal back film without blistering and peeling by adding a material which can be decomposed and foamed by ultraviolet irradiation to a suspension of acrylic resin copolymer. CONSTITUTION:An organic film 4 is prepared from a filming material comprised of 18wt.% of acrylic emulsion, 1wt.% of acrylic acid-cellulose copolymer, 0.2wt. of microcapsules composed with a diazo compound to be decomposed by ultraviolet as a core and acrylic acid-methcrylic acid copolymer as a wall film material by injecting to the inside of a panel at 42 deg.C while the panel is rotated. Ultraviolet-ray is radiated to the film to decompose the material 5 to be decomposed and foamed by ultraviolet-ray so as to produce a gas and using the gas pressure cracks are formed in the film and aluminum is evaporated on the film to give a metal back film 3. By this method, blistering the film is prevented even when the film is baked at 430 deg.C for 30 minutes.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides an organic material film used as a vapor deposition base for a metal back film formed inside a phosphor layer of a cathode ray tube.
The present invention relates to a filming material for the fluorescent surface of a cathode ray tube that prevents a metal back film from blistering or peeling during a baking process in which it is heated to decompose, vaporize, and diffuse.

[Prior Art] A metal back film is formed inside a phosphor layer that is formed in close contact with the inside of a cathode ray tube panel. One of the important functions of this metal back film is to act as a reflector for the light emitted by the phosphor layer, and by providing this film, the brightness on the panel surface side due to the light emitted by the phosphor layer is reduced to approx. It has doubled.

In order to smooth the surface of the metal back film facing the phosphor layer and increase reflection efficiency, a suspension of a water-insoluble organic substance such as acrylic resin is applied, dried, and formed into a film to smooth the surface. A film of organic material with a smooth inner surface is formed by the action of tension (filming), and a metal (currently usually aluminum) is deposited on the smooth surface to form a metal back film. I'm letting you do it. After the metal back film is formed, the surface of the metal back film is smoothed, so that the organic film that has completed its role is unnecessary, and also because it becomes a source of gas release when the cathode ray tube bulb is evacuated to a high vacuum. In the case of a color cathode ray tube, before the panel is sealed to the funnel with low-melting glass, the panel alone is left open and heated to about 430°C to evaporate moisture.
Decomposes organic films.

Vaporize and dissipate (baking).

The thicker the organic film, the smoother its inner surface, and the smoother the surface facing the phosphor layer of the metal back film deposited thereon, but the thicker the film, the smoother the surface of the metal back film deposited thereon, the smoother the surface facing the phosphor layer. If the amount increases too much, the amount of gas generated during the baking process will increase, making the metal back film more likely to swell or peel off as shown in FIG. In FIG. 2, 1 is a panel, 2a, 2b, and 2c are phosphor layers emitting light of different colors, and 3 is a metal back film (3a is a normal film, 3b is a swollen film).

As a countermeasure to the above-mentioned problems such as swelling of the metal back film, for example, Japanese Patent Publication No. 47-24416 discloses an emulsion (hereinafter referred to as The main ingredient is a water-soluble resin, hydrogen peroxide, and colloidal silica. Colloidal silica has the function of preventing the metal back film from blistering or peeling during the baking process.

[Problems to be Solved by the Invention] In the above-mentioned conventional countermeasure technology, colloidal silica remains as silica on the phosphor layer, and the silica has poor electron beam transmittance, so the electron beam does not fluoresce. There was an undesirable point where the silica acted as a barrier before reaching the phosphor layer, causing a decrease in the brightness of the fluorescent surface.

The present invention provides an organic film having a sufficiently thick and smooth surface;
Therefore, while forming a metal back film with high reflection efficiency, the cathode ray tube fluorescent light does not cause a decrease in brightness due to a decrease in the amount of electron beam that excites the phosphor, and also prevents the metal back film from blistering or peeling. The purpose of the present invention is to provide a surface filming material.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, a suspension of an acrylic resin copolymer is added with a material that decomposes and foams when irradiated with ultraviolet rays. I decided to use it as a filming material.

[Function] A film of an organic material, such as an acrylic resin, having a thickness of about 1 μm, for example, is formed using a filming material to which a material that foams when exposed to ultraviolet rays is added according to the present invention, and this is deposited prior to vapor deposition of a metal back film. When the film is irradiated with ultraviolet rays, 1
When the foam material foams and the organic film tears, protrusions are formed here and there on the surface of the film.If aluminum is vapor-deposited to a thickness of about 0.2 μm, for example, on top of this organic film, The above-mentioned protrusions block the trajectory of some aluminum atoms flying to be deposited on the organic film surface, and pinholes are formed here and there in the deposited aluminum film. When such a metal back film is formed, the gas generated by the thermal decomposition of the organic substance through the pinholes will be easily released to the outside of the aluminum film during the baking process, and the metal back film will not swell or peel. .

Note that, if the amount of foamed material added is appropriate, the protrusions will occur on the inner surface of the organic film, which will cause pinholes in the metal back film, but this will not cause problems such as a decrease in reflection efficiency.

[Example] Figure 1 is a cross-sectional view of a fluorescent surface of a cathode ray tube formed using the filming material of the present invention.
Reference numerals a, 2b, and 2c are phosphor layers of different luminescent colors, 3 is a metal (aluminum) backing film, 4 is an organic film made of acrylic resin, and 5 is a substance that decomposes and foams when irradiated with ultraviolet rays.

In this example, the following filming material was used.

Acrylic emulsion 18 wt% (solid content) Acrylic acid/cellulose copolymer 1 wt% Substance that decomposes and foams under ultraviolet light* 0.2 wt% Add water as microcapsules with the remainder of this filming material injected into the inner surface of the panel, and while rotating the panel, heat the acrylic emulsion at the optimum temperature for film formation.
Heating to 2°C formed an organic film. Next, this film was irradiated with ultraviolet rays to decompose the diazo compound of the ultraviolet decomposition foam material 5, and the resulting gas pressure caused cracks in the film.Aluminum was then vapor deposited to form the metal back film 3. Later, in the air atmosphere 4
Baking was performed at 30° C. for 30 minutes, but no blistering of the metal back film occurred.

Note that when a filming material having the same composition was used without adding only the ultraviolet decomposition foaming substance 5, swelling of the aluminum film occurred. In order to prevent the aluminum film from blistering without adding this ultraviolet decomposition foaming substance, it was necessary to reduce the content of the acrylic emulsion (in terms of solid matter) in the filming material to 17 wt%. However, as the solid content concentration is lowered, the thickness of the organic film filmed becomes thinner, making it impossible to cover the phosphor sufficiently, resulting in a decrease in the reflection efficiency of the aluminum film, and The brightness due to phosphor emission has decreased.

[Effects of the Invention] As explained above, according to the present invention, it is possible to form a metal back film having good reflectance without suffering from the occurrence of swelling or peeling of the metal back film.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the fluorescent surface of a cathode ray tube formed using the filming material of the present invention, and Figure 2 is the occurrence of blistering in the metal back film when filming is performed using a conventional filming material. It is a sectional view showing a state. DESCRIPTION OF SYMBOLS 1... Panel, 2a, 2b, 2c... Phosphor layers with different emission colors, 3, 3a, 3b... Metal back film, 4... Organic film, 5... Ultraviolet decomposition foaming material. Sai1koku4rz+m b

Claims (1)

[Claims] 1. After the phosphor layer is adhered to the inner surface of the panel of the glass bulb of the cathode ray tube, and before forming a metal back film on the inside of the phosphor layer by vapor deposition. , a film for forming an organic material film that is formed inside the phosphor layer, and after a metal back film is deposited in close contact with the smooth inner surface of the phosphor layer, it is heated to decompose, vaporize, and dissipate. In materials,
A filming material for a fluorescent surface of a cathode ray tube, characterized in that a material that foams when irradiated with ultraviolet rays is added to a suspension of an acrylic resin copolymer. 2. The filming material for a fluorescent surface of a cathode ray tube according to claim 1, wherein microcapsules having a core made of a material that foams when irradiated with ultraviolet rays are added to the suspension of the acrylic resin copolymer.