JPH10177841A - Fluorescent screen forming method for color picture tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce any brightness drop at a corner part by composing phosphor in phosphor slurry by means of phosphor of its size of 50% particle diameter by Coulter counter apparatus and setting the specific weight of this phosphor slurry in a specific range. SOLUTION: The coating film 25 of phosphor slurry is exposed to light via a mask 6 and correspondent patterns are baked on the opening 21 of the mask 6 so as to form blue, green and red phosphor layers 26B, 26G and 26R sequentially. The phosphor inside of phosphor slurry is composed of such one of 50% particle diameter of 4.5μm to 6.5μm by the Coulter counter apparatus, its specific gravity is set in a range from 1.200 to 1.300 and the maximum number of revolution of the panel at the time of uniformly applying this phosphor slurry on the effective part inside surface is set in a range from 150 to 250rpm. For instance, each colored phosphor layer is formed by using, respectively, a blue phosphor of 5.5μm particle diameter, a green phosphor of slurry specific gravity 1.260 with particle diameter 5.7μm, a red phosphor of slurry specific gravity 1.245 with particle diameter 5.8μm and such a one of specific gravity 1.255.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming a fluorescent screen of a color picture tube.

[0002]

2. Description of the Related Art In general, as shown in FIG. 3, a color picture tube has a substantially rectangular panel 3 having a skirt portion 2 provided around a curved effective portion 1 and a funnel funnel 4 as shown in FIG.
And an effective portion 1 of the panel 3 opposed to the shadow mask 5 arranged inside the panel 3.
A fluorescent screen 6 described later is provided on the inner surface. On the other hand, an electron gun 8 is provided on the neck 7 of the funnel 4. The three electron beams 9 emitted from the electron gun 8 are deflected by a deflector 10 mounted outside the funnel 4,
By scanning the phosphor screen 6 through the shadow mask 5, the color screen is formed.

As shown in FIG. 4, a black matrix 12a made of a black non-luminescent material is used as the fluorescent screen 6.
A black matrix type phosphor screen in which dot-shaped three-color phosphor layers 13B, 13G and 13R are provided in a circular gap (matrix hole), as shown in FIG. Shape 3
As shown in FIGS. 6 and 7, a black stripe type phosphor screen provided with color phosphor layers 13B, 13G and 13R is provided.
Dot or striped three-color phosphor layers 13B, 13G without black matrix or black stripe
, 13R.

Conventionally, these phosphor screens are formed by a photographic printing method using a shadow mask as an optical mask.
In particular, for the formation of the phosphor layer, for example, for a black matrix type or black stripe type phosphor screen,
After forming a black matrix or black stripe on the inner surface of the effective portion of the panel, the inner surface of the effective portion of the panel contains a phosphor, polyvinyl alcohol (PVA), ammonium bichromate (ADC), a surfactant, an acrylic emulsion, etc. A phosphor slurry is applied, and the phosphor slurry film is exposed through a shadow mask,
After the pattern corresponding to the opening of the shadow mask is printed, the pattern is developed to remove the unexposed portion.

Conventionally, the phosphor slurry has a 50% particle size by the Coulter counter method of 7 from the viewpoint of luminance.
A phosphor slurry having a specific gravity of 1.300 to 1.350 is used from the viewpoint of perforated quality of the phosphor screen.

To apply the phosphor slurry, a panel is installed with the inner surface of the effective portion facing upward, the phosphor slurry is injected into the inner surface of the effective portion of the panel, and the panel is rotated to inject the entire surface of the inner portion of the effective portion. After the phosphor slurry is spread, the maximum number of rotations is set to 250 so that an appropriate film thickness can be obtained.
It rotates at rpm to 300 rpm.

However, by forming a fluorescent screen of a high-definition color picture tube, which has been increasing in demand for display of computer equipment in recent years, by using such a method, the specific gravity of the phosphor slurry is high, and Since the rotation speed (maximum rotation speed) of the panel for adjusting the film thickness is high, the uniformity of the film thickness of the phosphor slurry is reduced, and the brightness at the corners is lower than that at the center of the screen. is there.

In order to increase the brightness at the corners of the screen, the specific gravity of the phosphor slurry may be reduced and the maximum number of rotations of the panel may be reduced.
If the maximum number of rotations of the panel is reduced, the perforated quality of the phosphor layer is deteriorated, so that it is difficult to put the phosphor layer to practical use.

[0009]

As described above, conventionally,
In forming the phosphor screen of the color picture tube, a phosphor having a 50% particle size by a Coulter counter method of 7 μm to 9 μm is used, and a phosphor slurry whose specific gravity is adjusted to 1.300 to 1.350 is used. After rotating, the injected phosphor slurry is spread over the entire inner surface of the effective portion, the maximum number of rotations is from 250 rpm to 300 rpm so that an appropriate film thickness is obtained.
The phosphor slurry is applied by rotating at rpm.

However, when the fluorescent screen of a high-definition color picture tube, which has been increasingly used for display of computer equipment in recent years, is formed by such a method, the film thickness of the phosphor slurry becomes less uniform, and the center of the screen is reduced. There is a problem that the brightness of the corner portion is lower than the portion. In order to increase the brightness at the corners of this screen, the specific gravity of the phosphor slurry may be reduced and the maximum rotation speed of the panel may be reduced. In this way, the specific gravity of the phosphor slurry is reduced and the maximum rotation speed of the panel is reduced. Then, the perforated quality of the phosphor layer is deteriorated, so that it is difficult to put the phosphor layer into practical use.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a color picture tube which can reduce a decrease in luminance at a corner portion with respect to a center portion of a screen and does not deteriorate the perforated quality of a phosphor layer. It is an object to obtain a phosphor screen forming method.

[0012]

The phosphor slurry is injected into the inner surface of the effective portion of the panel with the inner surface of the effective portion of the panel facing upward, and the phosphor slurry is injected over the entire inner surface of the effective portion by rotating the panel. In the method for forming a phosphor screen of a color picture tube, a 50% particle size of the phosphor in the phosphor slurry is from 4.5 μm to 6.5 μm by a Coulter counter method.
m.

The phosphor in the phosphor slurry has a 50% particle size of 4.5 μm to 6.5 μm by the Coulter counter method.
m of the phosphor, and the specific gravity of the phosphor slurry is 1.
200 to 1.300.

Further, the phosphor in the phosphor slurry has a 50% particle size of 4.5 μm to 6.50% by the Coulter counter method.
It is composed of a phosphor of 5 μm, the specific gravity of the phosphor slurry is 1.200 to 1.300, and the maximum number of rotations of the panel when the phosphor slurry is uniformly applied to the inner surface of the effective portion is 150 rpm to 250 rpm. did.

[0015]

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

FIG. 1 shows main steps of a method of forming a black matrix type phosphor screen as one embodiment. As shown in FIG. 1A, the black matrix phosphor screen
A photoresist 20 composed of PVA and ADC is applied to the inner surface of the effective portion of the panel 3 to form a photoresist 20. The photoresist 20 is exposed through the shadow mask 6 to correspond to the opening 21 of the shadow mask 6. Print the dot pattern. Next, the photoresist 20 on which the pattern has been baked is developed to remove unexposed portions.
As shown in FIG. 7, a resist 22 having a pattern corresponding to the openings of the shadow mask is formed. Next, as shown in (c), a black paint is applied to the inner surface of the effective portion of the panel 3 on which the resist 22 is formed to form a coating 23 of a black substance. Next, the black material layer 23 applied on the resist 22 is peeled and removed together with the resist 22, and as shown in FIG. A black matrix 12a to be (gap) is formed.

Thereafter, as shown in (e), the inner surface of the effective portion of the panel 3 on which the black matrix 12a is formed is coated with, for example, a blue phosphor by a coating method described later using a photosensitive phosphor slurry described later. Is applied to form a coating 25 of the phosphor slurry. Then, the coating 25 of the phosphor slurry is exposed through the shadow mask 6, and a dot pattern corresponding to the opening 21 of the shadow mask 6 is printed. Next, the baked phosphor slurry film 25 having this pattern is formed.
Is developed to remove the unexposed portions, and a dot-shaped blue phosphor layer 26B is formed in a predetermined matrix hole of the black matrix 12a as shown in FIG. Next, the above-described method for forming the blue phosphor layer 26B was repeated using a photosensitive green phosphor slurry containing a green phosphor and a photosensitive red phosphor slurry containing a red phosphor, which will be described later. As shown in the figure, a dot-like green phosphor layer 26G is formed in a predetermined matrix hole of the black matrix 12a.
And a red phosphor layer 26R are sequentially formed.

As shown by the broken line in FIG. 2, the above-mentioned phosphor slurry of each color is installed with the inner surface of the effective portion 1 of the panel 3 facing upward. The phosphor slurry is injected, and the low-speed rotation is continued in order to obtain the sedimentation of the phosphor and the uniformity of the coating film. Then, the panel 3 is rotated at a high speed by inclining at 140 ° to 160 ° (rotation angle θ), and the excess This is performed by shaking the phosphor slurry to form a uniform coating film, and heating and drying this.

The photosensitive phosphor slurry used comprises a phosphor, PVA, ADC, a surfactant and an acrylic emulsion, like the conventional phosphor slurry. As shown in Table 1, this photosensitive phosphor slurry has a 50% value of 50% of the cumulative volume% by the Coulter counter method.
% By weight (hereinafter referred to as 50% particle size by Coulter counter method) using a blue phosphor having a particle size of 5.5 μm and PVA
Using a blue phosphor slurry adjusted to a content of 3.00% and a specific gravity of 1.260, and a green phosphor having a 50% particle size of 5.7 μm as measured by the Coulter counter method, and a PVA content of 3.15. %, Specific gravity 1.245 using a green phosphor slurry adjusted to a specific gravity of 1.245, and a red phosphor having a 50% particle size of 5.8 μm by a Coulter counter method. Using the red phosphor slurry adjusted to 255, each of these color phosphor slurries is injected into the inside of the panel installed with the effective portion inner surface facing upward, and about 1
After rotating at low speed for 0 seconds, tilt about 155 ° for about 5 seconds,
By rotating at a high speed of a maximum of 210 rpm, each color phosphor layer was formed.

As a result, it was possible to form a desired phosphor screen with little perforation of the phosphor layer and little decrease in brightness at the corners with respect to the center.

[0021]

[Table 1] That is, the coating of the phosphor slurry of each color applied under the above-mentioned application conditions was applied to a phosphor slurry prepared using a conventional phosphor as Comparative Example 1, that is, as shown in Table 2, 50% by the Coulter counter method. Using a blue phosphor having a particle diameter of 7.0 μm, a blue phosphor slurry adjusted to have a PVA content of 3.00% (the same as in the above embodiment) and a specific gravity of 1.315, and a Coulter counter method. Using a 50% green phosphor having a particle size of 7.2 μm, a PVA content of 3.15% (the same as in the above embodiment) and a specific gravity of 1.285
Using a green phosphor slurry adjusted to 50% and a red phosphor having a 50% particle size of 7.1 μm in a Coulter counter method, a PVA content of 3.25% (the same as in the above embodiment) and a specific gravity of 1 Using the red phosphor slurry adjusted to 295, the high-speed rotation of the panel when applying the blue phosphor slurry is up to 280 rpm, the high-speed rotation of the panel when applying the green phosphor slurry is up to 280 rpm, and the red phosphor is used. Up to 290 high-speed panel rotation when applying slurry
rpm, and the phosphor slurry coating applied under the same conditions as in the above embodiment was compared with the coating weight per 16 cm ² . As a result, as shown in Table 3, in each of the coatings, the decrease in the film thickness at the corners with respect to the center could be reduced as compared with Comparative Example 1 using the conventional phosphor.

[0022]

[Table 2]

[Table 3] Further, regarding the perforated quality of the phosphor layer, the coating film of each color phosphor slurry applied under the above application conditions was coated with the coating film of each color phosphor slurry applied under the application conditions of Comparative Example 1 (Comparative Example 1), and Comparative Example 1 Similarly to the above, a conventional phosphor was used, and compared with a phosphor slurry film (Comparative Example 2) applied under the same conditions as in this embodiment, the results shown in Table 4 were obtained.

[0023]

[Table 4] Further, the white luminance (CIE chromaticity value of x) of a color picture tube formed by applying each color phosphor slurry under the above application conditions.
= 0.281, y = 0.311, the luminance at a constant current value when reproducing white) and the white luminance ratio of the corner part to the center part are compared with those of the conventional color picture tube.
As shown in Table 5, good results were obtained.

[0024]

[Table 5] In the above embodiment, the 50% particle size of each of the blue, green, and red phosphors measured by the Coulter counter method is 5.5.
μm, 5.7 μm, and 5.8 μm, and the specific gravities of the respective phosphor slurries were 1.260, 1.245, and 1.2, respectively.
55, and the high-speed rotation at the time of applying each of the phosphor slurries was 210 rpm at maximum. For the phosphor, the 50% particle size of the blue, green, and red phosphors by the Coulter counter method was 4.5 μm. 6.5 μm, the specific gravity of each color phosphor slurry is 1.200 to 1.300,
In addition, by setting the maximum high-speed rotation when applying each color phosphor slurry to 150 rpm to 250 rpm,
A similar phosphor screen can be formed.

That is, as shown in Table 6, for the green phosphor, the 50% particle size by the Coulter counter method ranges from 5.0 μm to 4.0 μm, and the relative luminance at the optimum film thickness is determined. Large drop of 4.5 μm
Is a necessary limit for maintaining luminance.

[0026]

[Table 6] On the other hand, as a result of measuring the number of pinholes of 20 μm to 30 μm in the green phosphor layer formed in the matrix holes of the black matrix, as shown in Table 7, the 50% particle size by the Coulter counter method was 5.0 μm. To 7.0 μm
6.5 μm in the middle
Was found to be the limit required to maintain perforated quality.

[0027]

[Table 7] As for the specific gravity of the phosphor slurry, the specific gravity was 1.180 as shown in Table 8 for a slurry using a green phosphor having a 50% particle size of 5.5 μm by the Coulter counter method.
In the case of (1), the number of pinholes of 20 μm to 30 μm in the green phosphor layer formed in the matrix holes of the black matrix increases. On the other hand, when the specific gravity is 1.330, the phosphor layer at the corner portion with respect to the central portion has As the specific gravity of the phosphor slurry decreases, the pinholes in the phosphor layer,
From the thickness of the phosphor layer at the corner with respect to the center, 1.
It turned out that 200-1.300 was the limit.

[0028]

[Table 8] Further, as to the maximum high-speed rotation when applying the phosphor slurry, the rotation speed was as high as 270 rpm as shown in Table 9 for a slurry using a green phosphor having a 50% particle size of 5.5 μm by the Coulter counter method. Thus, it was found that the upper limit of the maximum high-speed rotation was 250 rpm based on the thickness of the phosphor layer in the corner portion with respect to the center portion. When the rotation speed is as low as 270 rpm, the thickness of the phosphor layer at the corner portion with respect to the center portion is good, but the adhesion of the phosphor layer at the corner portion is reduced, and the phosphor layer is likely to fall off. It turned out to be the lower limit of high speed rotation.

[0029]

[Table 9] In the above embodiment, the phosphor layer has a dot-shaped phosphor screen. However, the present invention can be applied to the formation of a stripe-shaped phosphor screen.

[0030]

According to the present invention, the inside of the effective portion of the panel is directed upward to inject the phosphor slurry into the inside of the effective portion of the panel, and the panel is rotated to apply the phosphor slurry injected onto the entire surface of the inside of the effective portion. In the method for forming a phosphor screen of a picture tube, the phosphor in the phosphor slurry is composed of a phosphor having a 50% particle size of 4.5 μm to 6.5 μm by a Coulter counter method, and the phosphor in the phosphor slurry is also used. Has a 50% particle size of 4.5 μm to 6.5 μm by a Coulter counter method.
And the specific gravity of the phosphor slurry is 1.2.
The phosphor in the phosphor slurry has a 50% particle size of 4.5 as measured by the Coulter counter method of 4.5.
the phosphor slurry having a specific gravity of 1.200 to 1.300, and the maximum number of rotations of the panel when the phosphor slurry is uniformly applied to the inner surface of the effective portion. Assuming 150 rpm to 250 rpm,
It is possible to obtain a desired phosphor screen in which the phosphor layer has few holes and the entire phosphor screen has a uniform film thickness and the brightness at the corners with respect to the center is small, and is particularly suitable for display of computer equipment. A quality color picture tube can be constructed.

[Brief description of the drawings]

FIGS. 1A to 1G are diagrams showing main steps of a method of forming a black matrix phosphor screen according to an embodiment of the present invention.

FIG. 2 is a view for explaining a method of applying a phosphor slurry in the method of forming a phosphor screen.

FIG. 3 is a diagram showing a configuration of a color picture tube.

FIG. 4A is a plan view showing a configuration of a black matrix fluorescent screen, and FIG. 4B is a sectional view thereof.

FIG. 5A is a plan view showing a configuration of a black stripe type fluorescent screen, and FIG. 5B is a cross-sectional view thereof.

FIG. 6A is a plan view showing a configuration of a phosphor screen composed of only a dot-shaped phosphor layer, and FIG. 6B is a cross-sectional view thereof.

FIG. 7A is a plan view showing a configuration of a phosphor screen composed of only a stripe phosphor layer, and FIG. 7B is a cross-sectional view thereof.

[Explanation of symbols]

 1: Effective part 3: Panel

Claims (3)

[Claims] 1. The phosphor slurry is injected into the inner surface of the effective portion of the panel so that the inner surface of the effective portion of the panel faces upward, and the injected phosphor slurry is applied to the entire inner surface of the effective portion by rotating the panel. In the method for forming a phosphor screen of a color picture tube, the phosphor in the phosphor slurry is composed of a phosphor having a 50% particle size of 4.5 μm to 6.5 μm by a Coulter counter method. Phosphor screen forming method. 2. The phosphor slurry is injected into the inner surface of the effective portion of the panel with the inner surface of the effective portion facing upward, and the injected phosphor slurry is applied to the entire inner surface of the effective portion by rotating the panel. In the method for forming a phosphor screen of a color picture tube, the phosphor in the phosphor slurry is composed of a phosphor having a 50% particle size of 4.5 μm to 6.5 μm as measured by a Coulter counter method, and the specific gravity of the phosphor slurry is determined. 1.200-1.
300. A method for forming a phosphor screen of a color picture tube, wherein the method is 300. 3. A phosphor slurry is injected into the inner surface of the effective portion of the panel with the inner surface of the effective portion facing upward, and the injected phosphor slurry is applied to the entire inner surface of the effective portion by rotating the panel. In the method for forming a phosphor screen of a color picture tube, the phosphor in the phosphor slurry is composed of a phosphor having a 50% particle size of 4.5 μm to 6.5 μm by a Coulter counter method, and the specific gravity of the phosphor slurry is From 1.200 to
1.300, and the maximum number of rotations of the panel when this phosphor slurry is uniformly applied to the entire inner surface of the effective portion is 15
A method for forming a fluorescent screen of a color picture tube, wherein the rotation speed is from 0 rpm to 250 rpm.