JPH06349404A - Forming method of fluorescent screen in cathode-ray tube - Google Patents

Abstract

PURPOSE:To prevent withstand voltage faultiness between electron-gun electrodes and drop in quality of a fluorescent screen due to the swelling or stripping of an aluminum film and the fallng of its debris in a color picture tube, which are caused by gas release at thermal decomposition of an organic film formed under an aluminum film in the formation of a fluorescent screen in a color picture tube. CONSTITUTION:Crystal of organic ammonium, 3, is formed by precipitation on a fluorescent screen 2 formed on a glass panel 1. Then, an organic film 4 is formed for an aluminum film 5 to be smooth. Fine irregularity is formed on the fluorescent screen due to the organic ammonium crystal 3, so that the organic film 4 is easily decomposed. Damage of the aluminum film 5 is thus eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a fluorescent screen of a cathode ray tube.

[0002]

2. Description of the Related Art As a conventional example, a color cathode ray tube will be described in order to facilitate understanding of the present invention. As shown in FIG. 2, the color cathode ray tube includes a glass panel portion 6 coated with phosphors of three primary colors, a funnel portion 7 joined to the panel portion 6, and a funnel portion 7 joined together to emit an electron beam. It has a neck portion 8 for accommodating a gun, and is composed of a shadow mask 9 placed in opposition to the phosphor layer. Generally, the phosphor layer of the panel section 6 is formed as follows. First,
Phosphor particles are suspended in a photosensitive binder, coated on the inner surface of the panel, dried with an infrared heater, and then exposed through a shadow mask having a large number of holes to be photocured. Next, development is performed to remove the uncured portion and form a predetermined phosphor dot. The same treatment as green, blue, and red is sequentially performed to form a phosphor dot array of three colors on the inner surface of the panel, and then an organic film such as a lacquer is formed on the surface. Next, a metal such as aluminum is deposited by vacuum deposition. After that, heat treatment is performed to remove the binder and organic film of the phosphor dots by carbonization, leaving only the phosphor and the aluminum vapor deposition film on the inner surface of the panel. Next, the funnel portion is sealed and the electron gun is sealed, and a high vacuum is applied to complete the color cathode ray tube.

Many methods have been proposed for forming this film. Next, those examples are described. First,
As one of them, as shown in FIG. 3, a water-soluble emulsion liquid is applied on the inner surface of the glass panel 10 on which the fluorescent screen 11 is formed and dried to form a film 13. As the composition of this emulsion liquid, an organic peroxide is mixed in the acrylic emulsion to enhance its flammability, and the film 1
3 is a method for improving the brightness by eliminating the combustion residue (for example, Japanese Patent Laid-Open No. 54-49060). Further, as shown in FIG. 4, the fluorescent surface 15 is rewetted on the inner surface of the glass panel 14 on which the fluorescent surface 15 is formed, with the water-soluble organic solvent rewetting liquid 16, and the lacquer film 17 is formed.
Aluminum film 18 to be formed next to improve compatibility with
A method of improving the adhesiveness with the aluminum film 18 and eliminating the peeling of the aluminum film 18 (for example, Japanese Patent Laid-Open No. SHO 61-1955)
40), and as shown in FIG. 5, the lacquer film 21 is formed on the inner surface of the glass panel 19 on which the fluorescent screen 20 is formed.
In addition, a method of forming an aluminum film 22 and a heat absorbing material 23 is also known.

[0004]

In the conventional method of using an organic peroxide to increase the thermal decomposability of a water-soluble emulsion shown in FIG. 3, gas is generated by rapid decomposition of the peroxide itself during thermal decomposition. The swelling of the aluminum film causes swelling and peeling. In a color cathode-ray tube having such a metal back film, the metal back film peels and falls off even during operation, and the debris adheres to the fluorescent film, shadow mask, and electron gun to lower the quality of the fluorescent screen, and withstand voltage. There was a defect that caused defects. Further, according to the method of FIG. 4, since the water-soluble organic solvent used as the rewetting liquid in forming the lacquer film does not easily have an affinity with the lacquer film, the lacquer film is uniformly formed on the entire fluorescent film within a predetermined time. It is difficult to do so, and in particular, an uneven portion is likely to occur in the lacquer film around the glass panel. Therefore, there is a problem in that the aluminum film deposited on the lacquer film causes unevenness in the reflection effect, which deteriorates the quality of the fluorescent screen during operation of the color cathode ray tube.

[0005]

The present invention is directed to a step of forming a lacquer film on a fluorescent surface formed on the inner surface of a glass panel, a step of forming a metal back film by aluminum vapor deposition on the lacquer film, and a lacquer film. In the method for forming a cathode ray tube phosphor screen, which comprises the step of thermally decomposing and removing, a method of forming a cathode ray tube phosphor screen, which comprises a step of rewetting with a water-soluble organic ammonium salt solution before forming a lacquer film, and then drying. .

[0006]

Embodiments of the present invention will now be described with reference to the drawings. Figure 1
FIG. 3 is a sectional view of a fluorescent screen formed on the inner surface of a glass panel of a color picture tube according to the present invention. As shown in FIG. 1, a fluorescent screen 2 formed on a glass panel 1 by a predetermined method.
There is. Then 0.2 to 5.0 of ammonium oxalate
After applying a wt% aqueous solution and drying to precipitate crystals of ammonium oxalate 3, a 0.05 to 0.1 wt% polyvinyl alcohol aqueous solution is applied as a rewetting agent, and a lacquer solution consisting of an organic solvent is applied and dried. The organic film 4 is obtained. After that, the aluminum film 5 is formed by vapor deposition. Crystals of ammonium oxalate formed here 3
Since it is formed not only on the fluorescent surface but also on the side surface of the glass panel, unevenness is formed on the smooth glass surface, and the adhesiveness of the aluminum film formed on it is mechanically maintained to improve the glass. The aluminum film 5 can be prevented from falling off and peeling from the panel 1, and the organic film film 4 becomes porous because the microscopic ruggedness of course is uniformly formed on the phosphor screen, and when it is thermally decomposed, it is as usual. A large amount of decomposition gas is locally generated, and the aluminum film 5 is not peeled off. Further, ammonium oxalate is easily decomposed during thermal decomposition, so that it does not hinder the emission of light on the fluorescent surface. Although the color cathode ray tube has been described above, it goes without saying that the present invention is not limited to this and can be applied to all cathode ray tubes including monochrome.

[0007]

As described above, according to the present invention, when the organic film is formed in forming the fluorescent screen of the cathode ray tube, the aluminum film is dropped or peeled off due to the decomposition gas at the time of the thermal decomposition of the organic film. By applying an aqueous solution of organic ammonium on the phosphor screen and precipitating the crystals, it is possible to prevent the aluminum film from falling off and peeling, and it is possible to produce a color cathode ray tube without a withstand voltage defect. Play.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a color cathode ray tube.

FIG. 3 is a diagram showing a conventional method for manufacturing a cathode ray tube.

FIG. 4 is a diagram showing a conventional method for manufacturing a cathode ray tube.

FIG. 5 is a view showing a conventional method for manufacturing a cathode ray tube.

[Explanation of symbols]

 1 Glass Panel 2 Fluorescent Surface 3 Organic Ammonium Crystal 4 Organic Film 5 Aluminum 6 Glass Panel Part 7 Funnel Part 8 Neck Part 9 Shadow Mask 10 Glass Panel 11 Fluorescent Surface 12 Aluminum Film 13 Film 14 Glass Panel 15 Fluorescent Surface 16 Rewetting Liquid 17 Lacquer Liquid 18 Aluminum film 19 Glass panel 20 Phosphor screen 21 Lacquer film 22 Aluminum film 23 Heat absorbing substance

Claims (2)

[Claims] 1. A step of forming a lacquer film on a fluorescent surface formed on the inner surface of a glass panel, a step of forming a metal back film by aluminum vapor deposition on the lacquer film, and a step of thermally decomposing and removing the lacquer film. A method for forming a fluorescent surface of a cathode ray tube, comprising the steps of: rewetting with a water-soluble organic ammonium salt solution before forming the lacquer film, and then drying. 2. The method for forming a fluorescent screen of a cathode ray tube according to claim 1, wherein a 0.2 to 5.0 wt% aqueous solution of ammonium oxalate is used as the water-soluble organic ammonium salt solution.