JPH0831320A - Method for forming fluorescent screen of cathode ray tube - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose is to stably form a lacquer film as a base of a metal vapor deposition film to a predetermined film thickness. [Structure] Phosphor layers 10B, 10 formed on the inner surface of panel 1
After wetting G, 10R, spray the lacquer on the wet phosphor layer while rotating the panel, and continue the rotation of the panel after the lacquer coating to make the coated lacquer uniform thickness. In the method for forming the phosphor screen of the cathode ray tube, which is dried to form the lacquer film 30 and the metal vapor-deposited film 11 is formed on the film, the rotational speed of the panel and the viscosity of the lacquer when the lacquer is applied by the spray method are specified. Set in a relationship.

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 such as a color cathode ray tube, and more particularly to a lacquer film having a uniform predetermined thickness for forming a metal deposition film on the back surface of a phosphor layer. The present invention relates to a method for forming a fluorescent screen of a cathode ray tube that is stably formed.

[0002]

2. Description of the Related Art As shown in FIG. 4, a color picture tube has an envelope composed of a panel 1 and a funnel 2, a fluorescent surface 3 is provided on the inner surface of the panel 1, and the fluorescent surface 3 faces the fluorescent surface 3. Then, the shadow mask 4 is arranged inside thereof. On the other hand, the electron gun 6 is arranged in the neck 5 of the funnel 2. Then, the three electron beams 7 emitted from the electron gun 6 are selected by the shadow mask 4 to select the phosphor screen 3
Are horizontally and vertically scanned to form a structure for displaying a color image.

The fluorescent screen 3 of this color picture tube is provided in the gap between the matrix- or stripe-shaped light absorbing layers 9 as shown in FIG. 5 for a black matrix type fluorescent screen and FIG. 6 for a black stripe type fluorescent screen. , Blue,
Dot-shaped or stripe-shaped three-color phosphor layers 10B, 10G, and 10R that emit green and red are formed in a predetermined arrangement to increase the emission brightness of these phosphor layers 10B, 10G, and 10R, and ionize them by an electron beam. In order to prevent the deterioration of the phosphor due to the collision of the gas molecules, a metal vapor deposition film 11 made of, for example, aluminum is provided on the back surface thereof. Similarly, a metal vapor deposition film is formed on the back surface of the phosphor screen formed of the three-color phosphor layer without the light absorption layer 9.

As shown in FIG. 7 for the phosphor screen having the light absorbing layer 9, such a phosphor screen is formed on the inner surface of the panel 1 by the photo printing method and the three color phosphor layers 10B and 10B.
After forming G and 10R, these light absorption layers 9 and 3 are formed.
The color phosphor layers 10B, 10G, 10R are wetted, and the wet light absorption layer 9 and the three-color phosphor layers 10B, 10G, 1 are wetted.
It is formed by forming a coating film 12 made of acrylic resin or the like on the back surface of 0R and using this coating film 12 as a base to vacuum-deposit aluminum to form a metal vapor deposition film 11.

As a method for forming the coating film 12, there are an emulsion method in which an acrylic resin is dispersed in water and an lacquer method in which an acrylic resin is dissolved in a solvent. In any of the methods, the light absorption layer 9 and the three-color phosphor layers 10B, 1
After wetting 0G, 10R, spray coating emulsion liquid or lacquer while still or rotating panel 1, then when panel 1 is stationary and sprayed, panel 1 is rotated and sprayed while rotating. It is formed by continuing the rotation to bring the applied emulsion liquid or lacquer to a uniform thickness and drying.

[0006]

As described above, the fluorescent screen of the color cathode-ray tube has a fluorescent screen in which the three-color fluorescent layer is provided in the gap between the light absorbing layers and a fluorescent screen in which the light absorbing layer is not provided. In each case, a metal vapor deposition film is formed on the back surface of the phosphor layer in order to enhance the emission brightness of the phosphor layer and prevent the phosphor from deteriorating due to collision of gas molecules ionized by the electron beam. Such a phosphor screen forms a light absorption layer or a three-color phosphor layer on the inner surface of the panel, wets the absorption layer or the three-color phosphor layer, and then backs the light absorption layer or the three-color phosphor layer. It is formed by forming a coating film made of an acrylic resin or the like on, and forming a metal vapor deposition film on this coating film as a base. As a method of forming a film as a base of the metal vapor deposition film, spray coating a lacquer in which an acrylic resin or the like is dissolved in a solvent while rotating the panel, and after the coating is continued, the panel is continuously rotated to remove the applied lacquer. There is a method in which a lacquer film is formed with a uniform thickness and dried to form a metal vapor deposition film on the lacquer film.

However, when the lacquer film is formed by the above method, there is a problem that the film thickness of the film is not constant and a fluorescent screen defect occurs. That is, the lacquer film formed by the above method is for preventing the metal to be subsequently deposited from permeating into the phosphor layer, and if this film is too thin, pinholes and film breakage occur, and vapor deposition The metal penetrates through these pinholes and film cut portions and enters the phosphor layer, black spots and unevenness occur on the phosphor screen, and the phosphor screen becomes defective. On the other hand, if the coating is too thick, the amount of gas generated from the underlying coating increases when the panel having the fluorescent screen and the funnel are heated to 400 ° C. or higher for sealing, and this generated gas causes However, there is a problem that the metal vapor deposition film floats and becomes defective.

The present invention is intended to solve the above problems, and an object thereof is to obtain a phosphor screen forming method capable of stably forming a lacquer film having a predetermined film thickness as a base of a metal vapor deposition film. To do.

[0009]

[Means for Solving the Problems] A phosphor layer is formed on the inner surface of a panel, and after the phosphor layer is wetted, a lacquer is spray-coated on the wet phosphor layer while rotating the panel,
A method for forming a fluorescent screen of a cathode ray tube, in which the panel is continuously rotated even after applying this lacquer so that the applied lacquer has a uniform thickness and then dried to form a lacquer film, and a metal deposition film is formed on the lacquer film. In, the rotation speed of the panel when spraying the lacquer
When the viscosity at 0.4-0.65 mpa · s is 82
~ 115 rpm, 0.66 to 1.20 mpa · s, 116 to 198 rpm, 1.21 to 4.50 mpa · s, 199 to 270 rpm, 4.51 to 7.50 mpa
・ At s, it was set to 271-330 rpm.

[0010]

In general, when the lacquer is applied while rotating the panel at a constant speed, the thickness of the applied lacquer depends on the viscosity of the lacquer. Therefore, if the rotation speed of the panel when applying the lacquer is set to the rotation speed according to the viscosity of the lacquer as described above, when the viscosity of the lacquer is low, the thickness of the lacquer to be applied will be decreased due to the slow rotation speed of the panel. If the lacquer can be thickened and the viscosity of the lacquer is high, the lacquer coating applied can be made thin due to the high rotational speed of the panel, and the lacquer coating formed can have a predetermined thickness.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on embodiments with reference to the drawings.

FIG. 1 and FIG. 2 show a method of forming a fluorescent screen of a color cathode ray tube which is an embodiment of the invention. First, a light absorption layer and a three-color phosphor layer are formed on the inner surface of the panel by a photo printing method. That is, first, as shown in FIG.
A photosensitive agent having polyvinyl alcohol (PVA) and ammonium dichromate (ADC) as the main components is applied to the inner surface of and is dried to form a photosensitive film 20. Then, the photosensitive film 20 is exposed through the shadow mask 4 to print a pattern corresponding to the electron beam passage hole 21 of the shadow mask 4. Next, the pattern-printed photosensitive film 20 is developed to remove the unexposed portion, and a resist film 22 having a pattern corresponding to the electron beam passage hole of the shadow mask is formed as shown in FIG. . Next, a black paint is applied to the inner surface of the panel 1 on which the resist film 22 is formed and dried to form a black paint layer 23 as shown in FIG. Then, the resist film 2 is treated with a release agent.
Along with 2, the black paint layer 23 on the resist film 22 is removed, and as shown in (d), a black light absorbing layer 9 having a gap 24 in the phosphor layer forming portion is formed.

Thereafter, a photosensitive phosphor slurry containing a phosphor, PVA and ADC as a main component is applied to the inner surface of the panel 1 having the light absorption layer 9 formed thereon and dried, as shown in (e). Then, the photosensitive phosphor slurry layer 26 is formed. Then, the photosensitive phosphor slurry layer 26 is exposed through the shadow mask 4, and a pattern corresponding to the electron beam passage hole 21 of the shadow mask 4 is printed. Then, the baked photosensitive phosphor slurry layer 26 having this pattern is developed to remove the unexposed portion, and as shown in FIG. 7 (f), for example, a blue phosphor layer is formed in a predetermined gap portion of the light absorption layer 9. Form 10B. After that, for the green and red phosphors, the same method as the method for forming the blue phosphor layer 10B is repeated, and as shown in (g), the green and red phosphor layers 10G are formed in the predetermined gaps of the light absorption layer 9. , 10R are formed.

Next, on the inner surface of the panel 1 on which the light absorption layer 9 and the three-color phosphor layers 10B, 10G and 10R are formed, pure water or a dilute aqueous solution of PVA or a dispersion of silica powder in water is dispersed. Are discharged from, for example, a nozzle having an inner diameter of 10 mm to obtain the light absorption layer 9 and the three-color phosphor layer 1
Moisten OB, 10G, 10R. Thereafter, the panel 1 moistened with the light absorption layer 9 and the three-color phosphor layers 10B, 10G and 10R is rotated to remove excess liquid, and
As shown in (a), the light absorption layer 9 and the three-color phosphor layer 1
A smooth thin liquid layer 28 is formed on the surfaces of 0B, 10G and 10R.

Next, the panel 1 on which the liquid layer 28 is formed
While rotating at a predetermined rotation speed, a lacquer described below is sprayed on the inner surface of the panel 1. After this lacquer spraying, the panel 1 is continuously rotated at the same or different rotation speed as the above-mentioned spraying to remove excess lacquer, and as shown in (b), the liquid layer 2
A lacquer layer 29 of uniform thickness is formed on 8. Further, the liquid layer 28 which wets the lacquer layer 29, the light absorption layer 9 and the three-color phosphor layers 10B, 10G and 10R is dried to obtain the light absorption layers 9 and 3 as shown in FIG.
A smooth lacquer film 30 is formed on the color phosphor layers 10B, 10G and 10R.

As the above-mentioned lacquer, there is used one in which an acrylic resin such as isobutyl methacrylate and nitrocellulose are dissolved in a solvent composed mainly of toluene. As a solvent for this lacquer, it is optional to add a solvent having a different boiling point such as ethyl acetate, methyl ethyl ketone or xylene to toluene in order to adjust the evaporation rate after spraying.

The rotation speed of the panel 1 during spraying of the lacquer is such that the viscosity of the lacquer at 25 ° C. is 0.4-0.
82-115 rpm, 0.66-
116 to 198 rpm at 1.20 mpa · s, 1.
199 to 270 rp for 21 to 4.50 mpa · s
m, 4.51 to 7.50 mpa ・ s, 271 to 33
Set to 0 rpm.

Next, using the lacquer film 30 as a base, aluminum is vacuum-deposited on the lacquer film 30 to form a metal vapor deposition film 11. The underlying lacquer film 30 is formed when frit glass is used to seal the panel on which the metal vapor deposition film 31 is formed and the funnel.
It is decomposed and removed by heating above 00 ° C.

When the metal back phosphor screen is formed by such a method, the lacquer film 30 as the base of the metal vapor deposition film 31 can be stably formed to a predetermined uniform film thickness, and the conventional lacquer film is too thin. Pinholes and film breakages caused by this, and the rise of the aluminum vapor deposition film caused by heating at the sealing between the panel and the funnel due to the lacquer film being too thick should be eliminated to form a good-quality fluorescent screen. You can

That is, generally, when the lacquer is applied while rotating the panel at a constant speed, the thickness of the applied lacquer depends on the viscosity of the lacquer. Therefore, the rotational speed of the panel when applying the lacquer as described above,
The viscosity of the lacquer at 25 ° C is 0.4-0.65 mpa
・ When s is 82-115 rpm, 0.66-1.20
When mpa · s, 116-198 rpm, 1.21-
3. When it is 4.50 mpa · s, 199 to 270 rpm, 4.
271 to 330 rpm at 51 to 7.50 mpa · s
And with the rotation speed depending on the viscosity of the lacquer, if the viscosity of the lacquer is low, the slow rotation speed of the panel can increase the thickness of the applied lacquer, and if the viscosity of the lacquer is high, the panel can be It is possible to reduce the thickness of the lacquer applied by the high rotation speed of, and to stably form the lacquer film formed to a uniform predetermined thickness. FIG. 3 shows the relationship between the viscosity of the lacquer and the rotational speed of the panel during and after the application of the lacquer. On the right side of the broken line 32, the film thickness of the lacquer film becomes too thin and pinholes and film breakage are observed. The region A in which the lacquer film is generated and the left side of the broken line 33 is a region B in which the film thickness of the lacquer film becomes too thick and the metal vapor deposition film rises. It is shown that it is possible to prevent pinholes, film breakage, and floating of the vapor-deposited metal film from occurring by setting the range within the range.

Several specific examples will be described below.

Concrete Example A light absorption layer and a three-color phosphor layer are formed on the inner surface of a panel of a 1.25-inch color cathode ray tube by a photo printing method, and the light absorption layer and the three-color phosphor layer are wetted, and After forming a smooth thin liquid layer on the surface, while rotating this panel, a spray gun (Spraying System co.
TG-SS (made by TG-SS: nozzle diameter 0.5 mm) is separated from the inner surface of the panel by 150 mm, and the lacquer having the composition shown in Table 1 is 3.0 kg / c.
Sprayed at m pressure. Then, the lacquer was rotated at the same rotation speed as when spraying to remove excess lacquer, dried to form a lacquer film, and aluminum was vacuum-deposited on the lacquer film to form a metal evaporated film.

[Table 1]

Table 2 shows the spray speed of the lacquer and the subsequent rotation speed of the panel, film breakage caused by the lacquer coating being too thin, and the panel being heated (about 400 ° C.) due to the lacquer coating being too thick. The relationship with the floating of the metal vapor deposition film, which occurs in (1), is shown as “Good” when the mark is “Good” and “Poor” when it is “X”.

[Table 2] The lacquer shown in Table 1 has a viscosity shown in FIG.
An example of a lacquer in the range of 7.50 mpa · s, which is shown as good in Table 2 in Table 2, but is generally used when spraying the lacquer and afterwards with a high rotational speed of the panel. A pinhole or film breakage occurred. On the contrary, when the rotation speed of the panel was 250 rpm or less, the metal vapor deposition film floated.

Specific Example 2. With respect to a panel of a 25-inch color cathode ray tube, a lacquer film was formed in the same manner as in Specific Example 1 using the lacquer having the composition shown in Table 3, and a metal vapor deposition film was formed on this lacquer film. The results of the cases are shown in Table 4.

[Table 3]

[Table 4]

The lacquer shown in Table 3 is an example of a lacquer having a viscosity in the range of 1.21 to 4.50 mpa · s shown in FIG. 3, and in the case of this lacquer, as shown in Table 4,
When the rotation speed of the panel is higher than 300 rpm, pinholes and film breakage occur, and the rotation speed of the panel is 150 r.
Lifting of the metal vapor deposition film occurred at a slow speed of pm or less.

Example 3 For a panel of a 25-inch color cathode ray tube, a lacquer film was formed in the same manner as in Example 1 using the lacquer having the composition shown in Table 5, and a metal vapor deposition film was formed on this lacquer film. The results of the cases are shown in Table 6.

[Table 5]

[Table 6]

The lacquer shown in Table 5 is an example of the lacquer having the viscosity shown in FIG. 3 in the range of 0.66 to 1.20 mpa · s. If the rotation speed of the panel is 150 rpm or more, pinholes and film breakage will occur, and the panel rotation speed will be 50 rpm.
Lifting of the metal vapor deposition film occurred in the following slow cases.

Example 4 For a panel of a 25-inch color cathode ray tube, a lacquer film was formed in the same manner as in Example 1 using the lacquer having the composition shown in Table 7, and a metal vapor deposition film was formed on this lacquer film. The results of the cases are shown in Table 8.

[Table 7]

[Table 8]

The lacquer of Table 7 is an example of a lacquer having a viscosity of 1.21 to 4.50 mpa · s shown in FIG. 3, and in the case of this lacquer, as shown in Table 8,
When the rotation speed of the panel is higher than 300 rpm, pinholes and film breakage occur, and the rotation speed of the panel is 150p.
When the thickness was slower than m, the metal vapor deposition film was lifted.

As shown in Table 1, Table 3, Table 5 and Table 7, the viscosity of the lacquer becomes high when the solid content in the solution, that is, the proportion of isobutyl methacrylate and nitrocellulose is high, In particular, as can be seen from Tables 3 and 7, the amount of nitrocellulose has a great influence. As is clear from Table 2, Table 4, Table 6, and Table 8, film breakage and floating of aluminum vapor deposition film that occur when spraying the lacquer of each composition shown in Table 1, Table 3, Table 5, and Table 7 It has been shown that defects such as stickiness generally correspond better with viscosity than the amount of solids in solution.

In the above embodiments, the phosphor screen of the color cathode ray tube provided with the light absorption layer was described, but the present invention is also applicable to the phosphor screen of the color cathode ray tube not provided with the light absorption layer. It can also be applied to the fluorescent screen of a cathode ray tube other than the color cathode ray tube.

[0032]

EFFECTS OF THE INVENTION After the phosphor layer formed on the inner surface of the panel is wetted, the lacquer is spray-coated while rotating the panel, and the panel is continuously rotated after the coating so that the applied lacquer has a uniform thickness. In a method for forming a phosphor screen of a cathode ray tube, in which a lacquer film is dried to form a metal vapor-deposited film on the lacquer film, the rotational speed of the panel when the lacquer is applied by a spray method is set to 25
8 when the viscosity at ℃ is 0.4 to 0.65 mpa · s
2 to 115 rpm, 0.66 to 1.20 mpa · s, 116 to 198 rpm, 1.21 to 4.50 mpa · s
At 199 ~ 270rpm, 4.51 ~ 7.50m
When pa · s is set to 271-330 rpm, a uniform lacquer film with a predetermined film thickness can be stably formed, and film breakage, pinholes, and lacquer caused by the conventional lacquer film being too thin. Since the coating film is too thick, it is possible to eliminate the floating of the metal vapor deposition film caused by the heating for sealing the panel and the funnel, and to form a phosphor screen of good quality.

[Brief description of drawings]

1A to 1G are views for explaining a method of forming a phosphor layer on a phosphor screen of a color cathode ray tube according to an embodiment of the present invention.

2 (a) to 2 (d) are views for explaining a method of forming a lacquer film on the phosphor layer and forming a metal vapor deposition film on the lacquer film.

FIG. 3 is a diagram showing a relationship between a viscosity of a lacquer for forming the lacquer film and a rotation speed of a panel when the lacquer is applied.

FIG. 4 is a diagram showing a configuration of a color cathode ray tube.

FIG. 5 (a) is a plan view of a phosphor screen in which dot-shaped phosphor layers are formed in gaps of a matrix-shaped light absorption layer,
FIG. 5B is a sectional view thereof.

FIG. 6A is a plan view of a phosphor screen in which a stripe-shaped phosphor layer is formed in a gap between stripe-shaped light absorption layers, and FIG. 6B is a cross-sectional view thereof.

FIG. 7 is a diagram for explaining a conventional method of forming the phosphor screen.

[Explanation of Codes] 1 ... Panel 9 ... Light absorption layer 10B, 10G, 10R ... Three-color phosphor layer 28 ... Liquid layer 29 ... Lacquer layer 30 ... Lacquer coating 31 ... Metal evaporated film

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Mitsuo Kurobuchi 1-9-2, Harara-cho, Fukaya-shi, Saitama Inside Fukaya Electronics Factory, Toshiba Corporation (72) Inventor Kazuo Sugita 1-9, Harara-cho, Fukaya-shi, Saitama No. 2 inside Toshiba Fukaya Electronics Factory

Claims (1)

[Claims] 1. A phosphor layer is formed on the inner surface of a panel, and after the phosphor layer is wetted, a lacquer is spray-coated on the wet phosphor layer while rotating the panel, and after the lacquer is applied, the lacquer is applied to the panel. In a method for forming a fluorescent surface of a cathode ray tube, in which the applied lacquer is dried to form a lacquer film by continuously rotating the applied lacquer to form a lacquer film, and spraying the lacquer described above. The rotation speed of the panel when the lacquer viscosity at 25 ℃ is 0.4 ~ 0.65
When mpa · s, 82 to 115 rpm, 0.66 to 1.
116-198 rpm, 1.21 at 20 mpa ・ s
~ 4.50 mpa · s, 199-270 rpm,
271-330r when 4.51 ~ 7.50 mpa ・ s
A method for forming a phosphor screen of a cathode ray tube, characterized in that the phosphor screen is set to pm.