JP2000076994A - Manufacture of cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a uniform application film of lacquer to prevent the quality of a fluorescent screen from degrading by improving the conditions for forming a resin film. SOLUTION: In a method for manufacturing a cathode-ray tube, including the process of wetting with water a fluorescent screen formed on the inner surface of a panel and the process of forming a resin film by rotating the panel for removal of extra water clinging to the fluorescent screen, then spraying lacquer to the back of the fluorescent screen while rotating the panel, and drying the lacquer applied by this spraying, the lacquer is sprayed plural number of times.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a cathode ray tube such as a color picture tube, and more particularly to an improved cathode ray tube spraying method of lacquer which is performed as a pretreatment for forming a metal deposition film on the back surface of a phosphor screen. And a method for producing the same.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 3, a color picture tube has an envelope composed of a panel 1 and a funnel 2 having a funnel shape, and a fluorescent screen 3 is provided on the inner surface of the panel 1.
A shadow mask 4 is arranged inside the fluorescent screen 3 at a predetermined distance from the fluorescent screen 3. On the other hand, an electron gun 7 for emitting three electron beams 6B, 6G, 6R is arranged in a neck 5 of the funnel 2. The three electron beams 6B, 6G, and 6R emitted from the electron gun 7 are deflected by a deflection yoke 9 mounted outside the funnel 2 to scan the phosphor screen 3 horizontally and vertically via a shadow mask 4. Thus, a structure for displaying a color image is formed.

As shown in FIG. 4 or FIG. 5, a black non-light-emitting layer 11 in the form of a stripe or a matrix and blue, green and red light so as to be buried in gaps between the non-light-emitting layers 11 as shown in FIG. There is a black stripe type or black matrix type phosphor screen provided with stripe or matrix phosphor layers 12B, 12G and 12R which emit light. Further, on the fluorescent screen 3 of these color picture tubes, an aluminum vapor-deposited film 13 is provided on the back surface in order to prevent the luminance degradation due to the impact of the gas in the tube ionized by the collision of the electron beam and to increase the emission luminance of the fluorescent screen 3. Is provided.

Conventionally, the aluminum vapor-deposited film 13 is formed by a non-light-emitting layer 11, a phosphor layer 12B,
After forming the phosphor screen 3 composed of 12G and 12R, the phosphor screen 3 is wetted with water. Then, the panel is rotated at a rotation speed of 60 to 90 rpm with the center axis of the panel as a rotation center axis to remove excess water adhering to the phosphor screen 3, and then the panel is rotated while rotating at a rotation speed of 40 to 60 rpm. Spray a lacquer containing a resin as a main component for 1 to 4 seconds. Further, the rotation of the panel is continued to shake off excess lacquer applied to the back of the phosphor screen 3. Next, the lacquer applied on the back surface of the phosphor screen 3 is dried to form a resin film. Thereafter, aluminum 13 is vacuum-deposited on the resin film.

The above resin film is decomposed and removed by heating in the subsequent color picture tube manufacturing process, and does not exist on the phosphor screen 3 of the completed color picture tube.

[0006]

As described above, the aluminum vapor-deposited film on the back of the phosphor screen of the color picture tube forms a phosphor screen on the inner surface of the panel by a photo printing method, and then wets the phosphor screen with water. Then, after rotating the panel to remove excess water adhering to the fluorescent screen, a lacquer mainly composed of an acrylic resin is sprayed while rotating the panel. Continue rotating the panel to shake off excess lacquer applied to the back of the phosphor screen. Next, the lacquer applied to the back of the phosphor screen is dried to form a resin film.
Thereafter, aluminum is formed on this resin film by vacuum evaporation.

However, when a resin film is formed by the above-described method, the resin film becomes uneven, and the unevenness of the resin film causes a non-uniform aluminum deposited film to be formed thereafter, thereby deteriorating the phosphor screen quality. is there. (A) If the amount of water adhering to the phosphor screen before spraying the lacquer is small, the lacquer coating film remaining on the back of the phosphor screen becomes thin and radial unevenness occurs. If the amount of water adhering to the surface is large, the lacquer coating film remaining on the back side of the phosphor screen will not be uniform and unevenness will occur. (C) Increasing the spray amount of the lacquer (prolonging the spray time) Or increasing the spray pressure), there is a problem that the phosphor screen is destroyed and a perforated defect occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and improves the conditions for forming a resin film on the back surface of the phosphor screen to make the coating film of the lacquer uniform, thereby deteriorating the phosphor screen quality. The purpose is not to be.

[0009]

Means for Solving the Problems (1) A step of wetting a fluorescent screen formed on the inner surface of the panel with water, rotating the panel to remove excess water adhering to the fluorescent screen, and then rotating the panel. While spraying lacquer on the back of the phosphor screen,
Drying the lacquer applied by the spray to form a resin film on the back surface of the phosphor screen, wherein the lacquer is sprayed a plurality of times.

(2) In the method for manufacturing a cathode ray tube of (1), after the first lacquer spray is performed, the second spray is performed after a predetermined time.

(3) In the method for manufacturing a cathode ray tube of (1), after the first lacquer spraying is performed, the applied lacquer is once dried, and then the second spraying is performed.

[0012]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 shows the main steps of forming a phosphor screen of a color picture tube according to one embodiment by a photographic printing method. First, as shown in FIG. 3A, polyvinyl alcohol (PVA) and ammonium bichromate (AD
A photosensitive agent containing C) as a main component is applied and dried to form a photoresist 20. Next, this photoresist 2
The panel 1 on which the 0 is formed is exposed with the shadow mask 4 mounted thereon, and the photoresist 20 is printed with a pattern corresponding to the electron beam passage holes 21 of the shadow mask 4.
Next, the baked photoresist 2 of this pattern
0 is developed to remove the unexposed portions, and a resist 22 having a pattern corresponding to the electron beam passage holes of the shadow mask is formed as shown in FIG. Next, a black non-light-emitting paint is applied to the inner surface of the panel 1 on which the resist 22 is formed, and dried to form a black non-light-emitting paint layer 23 as shown in FIG. Next, by using a release agent, the black non-light-emitting paint layer 23 applied on the resist 22 together with the resist 22 is peeled off, and as shown in FIG.
Is formed.

Next, a photosensitive phosphor slurry mainly containing a phosphor, PVA and ADC is applied to the inner surface of the panel 1 on which the black non-light-emitting layer 11 is formed, as shown in FIG. Next, a photosensitive phosphor slurry layer 26 is formed. Next, the panel 1 on which the photosensitive phosphor slurry layer 26 is formed is exposed by mounting a shadow mask 4 thereon, and a pattern corresponding to the electron beam passage holes 21 of the shadow mask 4 is formed on the photosensitive phosphor slurry layer 26. Bake. Next, the photosensitive phosphor slurry layer 26 on which the pattern is baked is developed to remove unexposed portions, and the phosphor layer is placed in a predetermined gap of the black non-light-emitting layer 11 as shown in FIG. For example, a blue phosphor layer 12B is formed. Further, for the green and red phosphors, the step of forming the blue phosphor layer 12B is sequentially repeated, and the green phosphor layer 12G and the red phosphor are disposed in predetermined gaps of the black non-light-emitting layer 11 as shown in FIG. The body layer 12R is formed.

Next, as shown in FIG. 1, the phosphor screen having the blue, green and red phosphor layers formed in the gaps between the black non-light-emitting layers is wetted with water, and the panel inner face is turned downward. Rotation is performed around the central axis as a rotation central axis to remove excess water adhering to the phosphor screen. Thereafter, as the panel is further rotated, as shown in FIG. 2, a lacquer mainly composed of an acrylic resin is sprayed at a predetermined pressure for a certain time from a spray nozzle 28 disposed opposite to the inner surface of the panel 1 to wet the liquid. It is applied to the back of the phosphor screen 3 that has been applied. After the spraying is stopped, the panel is kept rotating, and the excess lacquer applied to the back surface of the fluorescent screen 3 is removed by centrifugal force. After a lapse of a predetermined time, the lacquer is sprayed again at a predetermined pressure for a predetermined time.
Then, by continuing to rotate the panel, the fluorescent screen 3
Remove any excess lacquer applied to the back of the car. Thereafter, a resin film is formed on the back surface of the fluorescent screen 3 by, for example, drying with hot air.

Next, aluminum is coated on the resin film by vacuum evaporation to form a metal evaporation film.

In the color picture tube, a panel having a metal vapor-deposited film formed on the back surface of the fluorescent screen and a funnel-shaped funnel having an inner surface coated with a conductive film are then interposed via frit glass. The panel is positioned, heated in a sealing furnace, and the panel and the funnel are integrally joined by the frit glass. By the heating in the sealing furnace, the resin film on the back surface of the phosphor screen is decomposed and removed. Then, the electron gun is sealed in the neck of the integrally joined funnel, and then exhausted.

When the resin film is formed on the back surface of the phosphor screen as described above, when the lacquer is sprayed in two times, compared with the conventional method of forming a resin film in which the lacquer is sprayed only once, It is possible to make the thickness of the resin film thick and uniform, to reduce the fluorescent screen defects caused by the unevenness of the film generated in the case of the conventional single spray, and to provide a color picture tube which displays a high-quality image. it can.

As an example, the rotation of the panel before lacquer spraying is 85 rpm, and the rotation during lacquer spraying is 40 rpm.
Table 1 shows a comparison of the occurrence of film defects when the lacquer was sprayed for 3 seconds (conventional method) and when the lacquer was sprayed twice for 3 seconds (embodiment method). .

[0020]

[Table 1] As shown in Table 1, according to the method of this embodiment, the film defects were significantly reduced as compared with the conventional method.

Next, another embodiment will be described.

In the above embodiment, the lacquer is sprayed again at a predetermined time after the first lacquer spray is performed. However, as shown in FIG. 4, the first lacquer spray is performed at a predetermined pressure for a predetermined time. After the spraying is stopped, the panel is continuously rotated to remove excess lacquer applied to the back surface of the fluorescent screen 3 by centrifugal force. After that, the applied lacquer is dried once, and then the second lacquer spray is performed. It may be.

As described above, when the lacquer spray is divided into two times and the lacquer applied by the first spray is once dried in the meantime, a resin film with less film defects can be formed than in the above embodiment. And a color picture tube that displays a high-quality image.

In the above embodiment, the method of manufacturing a color picture tube has been described. However, the present invention can be applied to a method of manufacturing a cathode ray tube other than a color picture tube.

[0025]

As described above, when a resin film is formed on the back of the phosphor screen formed on the inner surface of the panel, the lacquer is sprayed in a plurality of times, and the conventional resin film is formed by a single spray. As compared with the case of the above, it is possible to reduce the defects of the fluorescent screen due to the unevenness of the film and to obtain a cathode ray tube displaying a high quality image.

[Brief description of the drawings]

FIG. 1 is a flowchart for explaining a method of forming a resin film and a metal deposition film on the back surface of a fluorescent screen of a color picture tube according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a method of spraying a lacquer on a back surface of a fluorescent screen of the color picture tube.

FIGS. 3A to 3G are diagrams for explaining a method of forming the fluorescent screen of the color picture tube.

FIG. 4 is a flowchart for explaining a method different from the method of forming a resin film and a metal deposition film on the back surface of the fluorescent screen of the color picture tube.

FIG. 5 is a diagram showing a configuration of a color picture tube.

FIG. 6A is a plan view showing a configuration of a black stripe type fluorescent screen of a color picture tube, and FIG. 6B is a sectional view thereof.

7A is a plan view showing a configuration of a black matrix type fluorescent screen of a color picture tube, and FIG. 7B is a sectional view thereof.

[Explanation of symbols]

 1 Panel 3 Fluorescent screen 28 Spray nozzle

Claims (3)

[Claims] 1. A step of wetting a phosphor screen formed on an inner surface of a panel with water, rotating the panel to remove excess water adhering to the phosphor screen, and then rotating the panel to rotate the phosphor screen. Spraying a lacquer on the back side of the surface, and drying the lacquer applied by the spray to form a resin film on the back side of the phosphor screen, wherein the lacquer is sprayed a plurality of times. A method for manufacturing a cathode ray tube, comprising: 2. The method for producing a cathode ray tube according to claim 1, wherein after the first lacquer spray is performed, a second spray is performed after a predetermined time. 3. The method for producing a cathode ray tube according to claim 1, wherein after the first lacquer spray is performed, the applied lacquer is dried once, and then the second spray is performed.