JPH08212924A - Fluorescent screen forming method for color cathode-ray tube - Google Patents

Abstract

PURPOSE: To provide a fluorescent screen forming method whereby a fluorescent material layer in small size can be formed by using a large particle phosphor. CONSTITUTION: In a fluorescent screen forming method for a color cathode-ray tube whereby a fluorescent screen is formed by a photographic printing method, a dispersion liquid, contains at least one kind of Sn oxide, In oxide and Sb oxide and Si oxide by 1/10 to 100/10 weight ratio, is applied to an internal surface of a panel 1, dried and burned to form a transparent conductive thin film 20. A fluorescent screen comprising 3-color phosphor layers 5B, 5G, 5R and a photoabsorptive layer 6 or a fluorescent screen comprising the 3-color phosphor layer is formed on this transparent conductive thin film means of a photographic printing method.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Generally, as shown in FIG. 3, a color cathode ray tube has an envelope composed of a panel 1 and a funnel-shaped funnel 2 integrally joined to the panel 1, and a large number of them are provided inside the panel 1. The shadow mask 3 in which the electron beam passage holes are formed is arranged, and the phosphor screen 4 is formed on the inner surface of the panel 1 so as to face the shadow mask 3. This phosphor screen 4 is, as shown in FIGS. 4 (a) and 4 (b),
Dots or stripes that emit blue, green, and red 3
Color phosphor layers 5B, 5G, 5R, and these phosphor layers 5B,
It is composed of a black light absorption layer 6 provided between 5G and 5R. On the other hand, in the neck 8 of the funnel 2, 3 electron beams 9
An electron gun 10 that emits B, 9G, and 9R is arranged. Then, the three electron beams 9B, 9G and 9R emitted from the electron gun 10 are deflected by a magnetic field generated by a deflecting device 11 mounted outside the funnel 2 to horizontally and vertically scan the phosphor screen 4. Is formed into a structure for displaying a color image.

The fluorescent screen of the color cathode ray tube is conventionally formed by a photographic printing method, and as shown in FIG. 5 (a), the inner surface of the panel 1 is exposed at the portion where the three-color phosphor layer is first formed. Alternatively, the light absorption layer 6 having a stripe pattern is formed. After that, as shown in (b) of FIG.
It is formed by forming the color phosphor layers 5B, 5G and 5R.

By the way, it is generally desired that the phosphor screen of a color cathode ray tube is formed of a phosphor having a particle size distribution including a large particle phosphor. This is a large particle phosphor (particle size 8 μm
The above) has higher luminous efficiency than medium particle phosphors (particle size 5 to 7 μm) and small particle phosphors (particle size 5 μm or less).
This is because the brightness does not change much even if the film thickness of the phosphor layer changes.

However, EWS (Engneering Work St
ation) and CAD (Computor aid Desgin), high-definition color cathode-ray tubes have a phosphor layer size of approximately 100μ, such as the phosphor layer dot diameter and stripe width.
m, which is much smaller than that of an ordinary color cathode-ray tube and has a weak adhesive force, so that it is likely to fall off during the phosphor screen formation process. On the other hand, the large particle phosphor has a smaller contact area with the inner surface of the panel and a weaker adhesive force than the medium particle phosphor and the small particle phosphor. Therefore, conventionally, the above-mentioned high-definition color cathode-ray tube cannot be formed using a large particle phosphor, and a medium particle phosphor is used. as a result,
A high-definition color cathode-ray tube has a central portion and a peripheral portion that are different from those when a large-particle phosphor is used to form the fluorescent layer because of the difference in the thickness of the fluorescent layer between the central portion and the peripheral portion of the phosphor screen. Has a large brightness difference, and the peripheral part is darker than the central part.
Further, since the three-color phosphor layers have different brightness differences due to changes in film thickness, there is a problem that white uniformity is deteriorated.

[0006]

As described above, the phosphor screen of the color cathode ray tube is formed by the photo printing method, and the phosphor layer has high luminous efficiency and the thickness of the phosphor layer varies. There is a demand for a large-particle fluorescent substance whose brightness does not change so much. However, for high-definition color cathode ray tubes used for EWS and CAD, the size of the phosphor layer, such as the dot diameter of the phosphor layer and the width of the stripe, is much smaller than that of a normal color cathode ray tube, and its adhesion is weak. In the phosphor screen forming step, the phosphor layer is likely to fall off. Therefore, a medium particle phosphor is used for forming the fluorescent screen of a high-definition color CRT. As a result, the high-definition color cathode-ray tube has a central part that is different from the case where a large-particle phosphor is used to form the phosphor layer due to the difference in the thickness of the phosphor layer between the center part and the peripheral part of the phosphor screen. And the peripheral part has a large brightness difference, and the peripheral part is darker than the central part. Further, since the three-color phosphor layers have different brightness differences due to changes in film thickness, there is a problem that white uniformity is deteriorated.

The present invention has been made in order to solve the above-mentioned problems, and a phosphor layer of a color cathode ray tube having a small phosphor layer size is stably formed using a large particle phosphor. It is an object of the present invention to obtain a phosphor screen forming method that can be used.

[0008]

In a phosphor screen forming method of a color cathode ray tube for forming a phosphor screen by a photographic printing method, Sn oxide, I
A transparent conductive thin film is formed by applying a dispersion liquid containing at least one of n oxide and Sb oxide and Si oxide in a weight ratio of 1/10 to 100/10 to form a transparent conductive thin film. A fluorescent screen composed of a three-color phosphor layer and a light absorption layer or a fluorescent screen composed of a three-color phosphor layer was formed on the thin film by a photographic printing method.

In the method for forming the fluorescent screen of the color cathode ray tube, a transparent conductive thin film having fine irregularities is formed on the inner surface of the panel.

[0010]

As described above, when the transparent conductive thin film is formed on the inner surface of the panel and the fluorescent screen is formed on the transparent conductive thin film, the adhesive force of the fluorescent substance is increased and the fluorescent screen is formed by the large particle fluorescent substance. In addition, it is possible to increase the brightness by reducing the dead voltage (Ded Voltage) by preventing the phosphor layer from being charged, and stably forming a phosphor screen with high brightness and good white uniformity. be able to.

In particular, by forming a transparent conductive thin film having irregularities, it is possible to further enhance the adhesive force of the phosphor, and to use a large-particle phosphor to obtain a phosphor screen with high brightness and good white uniformity. It can be stably formed.

[0012]

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

As shown in FIG. 1A, first, on the inner surface of the panel 1, at least one of Sn oxide, In oxide and Sb oxide and Si oxide are in a weight ratio of 1/10 to 1000/10. Then, the dispersion liquid dispersed in alcohol is applied by spraying with a spray, the surface temperature of the panel 1 is set to 50 to 150 ° C., and the applied dispersion liquid is dried and fired to obtain the unevenness height of 0.
A transparent conductive thin film 20 having fine irregularities of 5 to 2 μm is formed.

Next, as shown in (b), polyvinyl alcohol (PVA) and ammonium dichromate (A) are formed on the inner surface of the panel 1 on which the transparent conductive thin film 20 is formed.
A photosensitizer containing DC as a main component is applied and dried to form a photoconductive film 21 on the transparent conductive thin film 20. Next, as shown in (c), the shadow mask 3 is attached to the panel 1 on which the photosensitive film 21 is formed, and the panel is exposed to light.
Then, a dot-shaped or stripe-shaped pattern corresponding to the electron beam passage hole 22 of the shadow mask 3 is printed. Next, the photosensitive film 21 having this pattern printed thereon is developed to remove the unexposed portion, and as shown in FIG.
3 is formed. Next, as shown in (e), a black paint containing graphite as a main component is applied to the inner surface of the panel 1 on which the resist 23 is formed and dried to form a black paint layer 24. Next, the black paint layer 24 applied on the resist 23 with the release agent is peeled off together with the resist 23, and the transparent conductive thin film 20 is exposed at the portion where the three-color phosphor layer is formed, as shown in (f). The matrix-shaped or stripe-shaped light absorption layer 6 having the gap portions 25 formed of the dot-shaped or stripe-shaped pattern is formed.

Thereafter, as shown in (g), the inner surface of the panel 1 on which the light absorption layer 6 is formed is coated with a phosphor and PV.
A photosensitive phosphor slurry having A and ADC as a main component is applied and dried to form a photosensitive phosphor slurry layer 26. As shown in (h), a shadow mask 3 is attached to the panel 1 on which the photosensitive phosphor slurry layer 26 is formed and exposed, and the photosensitive phosphor slurry layer 26 is exposed to electrons of the shadow mask 3. A pattern corresponding to the beam passage hole 22 is printed. Next, the baked photosensitive phosphor slurry layer 26 of this pattern is developed to remove the unexposed portion, and as shown in (i), a dot shape or a stripe shape is formed in the gap portion of the light absorption layer 6. A phosphor layer of any one color, for example, a blue phosphor layer 5B is formed. The method of forming the blue phosphor layer 5B is repeated for other green and red phosphors, and the same (j)
As shown in FIG. 3, dot-shaped or stripe-shaped three-color phosphor layers 5B, 5G and 5R are formed in predetermined gaps of the light absorption layer 6.

In forming the phosphor screen on the inner surface of the panel 1 as described above, the transparent conductive thin film 20 having fine irregularities is formed in advance, and the three-color phosphor layer 5B, 5B, is formed on the transparent conductive thin film 20. When 5G and 5R are formed, it becomes possible to increase the adhesive force of the phosphor, and to form a small-sized three-color phosphor layer 5B, 5G and 5R by using a large-particle phosphor, and also to charge the phosphor layer. It is possible to reduce the dead voltage and increase the brightness, and due to the large particle phosphor and the decrease in the dead voltage, it is possible to stably form a fluorescent surface with high brightness and good white uniformity. .

As one specific example of the above-mentioned phosphor screen forming method, a dispersion liquid in which alcohol is dispersed on the inner surface of the panel 1 in a ratio of SnO ₂ 0.5% by weight SbO ₂ 0.03% by weight SiO ₂ 1.5% by weight. Is sprayed on by a spray, and the dispersion liquid applied while maintaining the surface temperature of the panel 1 at 60 ± 5 ° C. is dried and fired to form a transparent conductive thin film 20. The phosphor is Zn
S: Ag, Cl, green-blue phosphor is ZnS: Cu, Au, A
As a result of forming the three-color phosphor layers 5B, 5G, 5R in which the red phosphor is Y ₂ O ₂ S: Eu, the relationship shown in FIG.

That is, in the conventional phosphor screen forming method in which the transparent conductive thin film is not formed on the inner surface of the panel, since the three-color phosphor layer is formed by using the medium particle phosphor, the blue, green and red phosphor layers are formed. , The relationship between the film thickness and the brightness is shown in the curve 28.
The relationship shown by B, 28G and 28R is obtained. However, when a transparent conductive thin film having fine irregularities is previously formed on the inner surface of the panel as in the phosphor screen forming method of this example, the fineness of the transparent conductive thin film is reduced. The unevenness increases the adhesiveness of the phosphor formed on it, and even if a large particle phosphor is used, it is possible to form the phosphor layer without dropping off the phosphor layer, such as blue, green, and red. Curve 29 for each phosphor layer
As indicated by B, 29G, and 29R, the brightness is increased, and the curve is gentler and higher than the curves 28B, 28G, and 28R of medium particle fluorescence. Therefore, even if the film thickness of the peripheral portion is smaller than the film thickness of the phosphor layer in the central portion of the panel, the brightness difference is small. Further, the film thickness of the blue, green, and red phosphor layers can be controlled to reduce the difference in brightness between the phosphor layers of the respective colors. As a result, it is possible to increase the brightness of the fluorescent screen and to stably form a fluorescent screen with good white uniformity.

When a conductive thin film is further formed and a phosphor layer is formed on this conductive thin film, the conductivity of the phosphor layer can be prevented and the dead voltage can be reduced. The brightness of the body layer can be increased.

In the above embodiment, the case where the transparent conductive thin film having fine irregularities is formed on the inner surface of the panel has been described. However, a smooth transparent conductive thin film is formed and fluorescent light is applied on the transparent conductive thin film. Even if the surface is formed, it is possible to prevent the phosphor layer from being charged due to its conductivity, reduce the dead voltage, and increase the emission brightness of the phosphor layer.

In the above embodiment, the method for forming the phosphor screen composed of the light absorption layer and the phosphor layer has been described. However, the present invention has a phosphor screen composed of a three-color phosphor layer having no light absorption layer. Can also be applied to the formation of

[0022]

According to the method of forming a phosphor screen of a color cathode ray tube for forming a phosphor screen by a photo printing method, at least one of Sn oxide, In oxide and Sb oxide and Si oxide are formed on the inner surface of the panel of the color cathode ray tube. 1/10 to 10
A dispersion containing 0/10 by weight is applied, dried and baked to form a transparent conductive thin film, and a fluorescent screen composed of a three-color phosphor layer and a light absorption layer is formed on the transparent conductive thin film by photo printing. When the phosphor screen composed of the three-color phosphor layer is formed, it becomes possible to enhance the adhesive force of the phosphor and to form a phosphor layer having a large size and a small size, and to prevent the phosphor layer from being charged. By reducing the dead voltage and decreasing the large particle phosphor and the dead voltage, it is possible to stably form a phosphor screen with high brightness and good white uniformity.

By using a transparent conductive thin film having irregularities, the adhesive force of the phosphor can be further increased, and a phosphor screen with high brightness and good white uniformity can be formed more stably.

[Brief description of drawings]

1 (a) to 1 (j) are views for explaining a phosphor screen forming method of a color cathode ray tube according to an embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between the film thickness and the brightness of a three-color phosphor layer formed by the above-mentioned phosphor screen forming method in comparison with that of a three-color phosphor layer formed by a conventional phosphor screen forming method. is there.

FIG. 3 is a diagram showing a configuration of a color CRT.

FIG. 4 (a) is a diagram showing a structure of a phosphor screen including a dot-shaped three-color phosphor layer and a light absorption layer provided therebetween;
FIG. 4B is a diagram showing a structure of a phosphor screen including a stripe-shaped three-color phosphor layer and a light absorption layer provided therebetween.

5A and 5B are diagrams for explaining a conventional phosphor screen forming method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Panel 3 ... Shadow mask 5B, 5G, 5R ... 3-color fluorescent substance layer 6 ... Light absorption layer 20 ... Transparent conductive film

Claims (2)

[Claims] 1. Sn is formed on the inner surface of a panel of a color cathode ray tube.
At least one of oxide, In oxide, and Sb oxide and S
a step of forming a transparent conductive thin film by applying a dispersion liquid containing i oxide in a weight ratio of 1/10 to 100/10, and forming a transparent conductive thin film by the photo printing method on the transparent conductive thin film. A method of forming a phosphor screen of a color cathode ray tube, comprising the steps of forming a phosphor screen composed of a body layer and a light absorption layer or a phosphor screen composed of a three-color phosphor layer. 2. The method for forming a fluorescent screen of a color cathode ray tube according to claim 1, wherein a transparent conductive thin film having fine irregularities is formed on the inner surface of the panel.