JPH11224616A - Color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration of luminance caused by the statics on of phosphor layers and to improve display characteristics such as luminance and contrast by providing a transparent conductive film having the surface resistance of a specific value or below between a filter layer and the phosphor layers. SOLUTION: A transparent conductive film 8 is provided on an optical filter layer 7, and blue, green and red phosphor layers 9 are formed on it by the normal slurry method respectively. Indium tin oxide(ITO), antimony tin oxide(ATO) or tin oxide is used as the material constituting the transparent conductive film 8. The vapor phase method such as the PVD method, a CVD method or a spattering method or a coating method or the like in which a solution dispersed with fine grains of a transparent conductive oxide such as ITO is applied by spin coating or the like and a paint film is dried, hardened or backed is used for the forming method. The surface resistance of the transparent conductive film 8 is set to 1×10<10> Ω/cm<2> or below.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube having an optical filter layer.

[0002]

2. Description of the Related Art In recent years, in a color cathode ray tube, in order to improve image characteristics such as luminance, color purity, and contrast, the color of the phosphor emitted between the face plate and the phosphor layer on the inner surface of the panel is adjusted. It is widely practiced to provide an optical filter layer as described above.

That is, in a normal color cathode ray tube, a phosphor pattern in which phosphor layers of blue, green, and red are arranged in a dot shape, a stripe shape, or the like is formed on an inner surface of a face plate panel. When an electron beam collides with the phosphor layer, the phosphor emits light of each color to display an image. In a color cathode-ray tube having a filter layer, as shown in FIG. A filter layer 3 composed of pigment layers 3B, 3G, and 3R of each color that transmits light of the same color as the emission color of the phosphor layer 2 is provided between the first and second layers. Of the incident external light, green and blue component light is red pigment layer 3R, and green and red component light is blue pigment layer 3R.
In B, light of blue and red components is absorbed by the green pigment layer 3G. Note that reference numeral 4 in the drawing denotes a black matrix which is a light absorbing layer. This layer is formed of a light absorbing material such as graphite and has conductivity.

[0004]

However, in such a color cathode ray tube, an insulating filter layer 3 is interposed between the phosphor layer 2 and the conductive black matrix 4, so that the phosphor layer Since the conductive layer 2 is not electrically connected to the conductive layer, charging of the phosphor layer 2 due to collision of an electron beam or the like is increased, and as a result, there is a problem that luminance is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. In a color cathode ray tube having an optical filter layer, a reduction in emission luminance due to charging of a phosphor layer is prevented, and luminance and contrast are reduced. It is an object to improve display characteristics such as

[0006]

The color cathode ray tube according to the present invention is a color cathode ray tube having an optical filter layer on an inner surface of a panel of a face plate and a phosphor layer of each color arranged in a predetermined pattern on the outside thereof. A transparent conductive film is provided between the filter layer and the phosphor layer.

Hereinafter, each content will be described in more detail.

In the present invention, the optical filter layer is constituted by arranging pigment layers of a plurality of colors in a predetermined pattern such as a dot shape or a stripe shape. As the pigment, any of inorganic or organic pigments can be used.
In particular, it is preferable to use a pigment which can be uniformly dispersed in the filter layer and has sufficient transparency without causing light scattering. In addition, since the production of a color cathode ray tube involves a high-temperature step, it is preferable to use an inorganic pigment.

Specific examples include the following pigments.

As a red pigment, ferric oxide-based pigment, Sicotrans Red L-2817 (particle size: 0.01 μm to
0.02 μm, manufactured by BASF), Chromophtal Red A2B (trade name: 0.01 μm, an anthraquinone pigment)
m, manufactured by Ciba Geigy Co., Ltd.), as a blue pigment, cobalt blue X (particle size: 0.01 μm to 0.02 μm, manufactured by Toyo Pigment Co., Ltd.), which is a cobalt aluminate (Al ₂ O ₃ —CoO) pigment; No. 8000 (particle size 0.03 μm, manufactured by Daiichi Kasei Co., Ltd.), a phthalocyanine blue pigment, brand name Lionol Blue FG-7370 (particle size 0.01 μm, manufactured by Toyo Ink Co., Ltd.), Ti as a green pigment
O ₂ -NiO-CoO-ZnO system, which is a pigment of the product name die Piroki side TM- Green # 3320 (particle diameter of 0.01μm ~
0.02 μm, manufactured by Dainichi Seika Co., Ltd.), CoO—Al ₂ O ₃ —Cr
A ₂ O ₃ pigments tradename die Piroki side TM- Green # 3420 (particle diameter 0.01 [mu] m ～0.02Myuemu, Dainichi Seika Co.), the trade name ND-801 (particle is a pigment of Cr ₂ O ₃ system Diameter
0.35μm, manufactured by Nippon Denko Co., Ltd., a product name of Fast Chlor Green S, a chlorinated phthalocyanine green pigment
(Particle size: 0.01 μm, manufactured by Dainippon Ink) and brominated phthalocyanine green pigment, trade name Fastgen Green 2YK (particle size: 0.01 μm, manufactured by Dainippon Ink Co., Ltd.).

In the present invention, the formation of a filter pattern comprising such a pigment layer is performed, for example, in Japanese Patent Application No. 6-315059.
As described in Japanese Patent Laid-Open Publication No. H10-205, the following procedure is performed.

That is, first, a pigment dispersion mainly composed of pigment particles and a polymer electrolyte dispersant is applied to the inner surface of a panel of a face plate having a black matrix.
As a coating method, a spin coating method, a roller method, a dipping method, or the like can be used.
It can be appropriately selected in consideration of the size and the like. In order to obtain a uniform and predetermined film thickness, it is particularly preferable to use a spin coating method. After coating in this manner, the coating film is dried. The drying method is not particularly limited as long as the method can evaporate water and dissociate a part of the salt in the polymer electrolyte salt. Various methods can be used, such as drying, drying with hot air, and drying at room temperature for a long time.

In order to perform patterning using only the pigment layer, it is necessary to use ammonium bichromate (AD) in the pigment dispersion.
C) / polyvinyl alcohol (PVA), sodium bichromate (SDC) / PVA, diazonium salt / PVA
It is only necessary to include a photoresist such as If a pigment layer containing such a photoresist is applied and formed, light (ultraviolet light) can be obtained by exposure using a high-pressure mercury lamp or the like.
The irradiated portion is cured, and then developed using an alkaline aqueous solution containing a substance that solubilizes the polymer electrolyte that has become insoluble in water or the like, whereby a predetermined filter pattern can be formed.

Instead of including the photoresist in the pigment dispersion liquid as described above, a pigment layer may be applied and formed as a photoresist layer thereon, and then exposed and developed. In such a case, the photosensitive characteristics are improved, the exposure time is shortened, the adhesion is improved, and the thickness range of the formed filter layer can be expanded.

By repeating these series of steps, usually in the order of blue, green and red, a filter layer comprising three color pigment layers of blue, green and red can be formed.

In the present invention, a transparent conductive film is provided on the optical filter layer thus formed, and blue, green, and red phosphor layers are further formed thereon by a usual slurry method. You. Here, as a material constituting the transparent conductive film, ITO (indium tin oxide), ATO (antimony tin oxide), tin oxide and the like can be mentioned, and use of ITO or ATO is particularly preferable. As a method of forming such a conductive thin film, PVD is used.
A liquid in which fine particles of a transparent conductive oxide such as ITO are dispersed is applied by spin coating, spray coating, or the like, and a coating film is formed. Any of the application methods (wet process) of drying and curing or baking can be adopted.

Further, it is desirable that the surface resistance of such a transparent conductive film be 1 × 10 ¹⁰ Ω / cm ² or less. If the surface resistance exceeds 1 × 10 ¹⁰ Ω / cm ² , the conductivity of the thin film becomes insufficient, and the effect of preventing the phosphor layer from being charged and improving the brightness is hardly obtained.

FIG. 1 shows a main part of the color cathode ray tube of the present invention. In the figure, reference numeral 5 denotes a panel of a face plate, reference numeral 6 denotes a black matrix made of a light absorbing substance such as graphite, and reference numeral 7 denotes a pigment layer 7B of each color of blue, green, and red.
7G and 7R are filter layers in which dots or stripes are arranged, reference numeral 8 is a transparent conductive film, and reference numeral 9 is a phosphor layer (blue, blue, etc.) having an emission color corresponding to each color pigment layer 7B, 7G, 7R. The phosphor layers of each color of green and red are respectively 9B and 9
G, 9R. ) Respectively.

In the thus constructed color cathode ray tube of the present invention, the black matrix 6 on the inner surface of the panel 5
A transparent conductive film 8 is interposed between the filter layer 7 and the phosphor layer 9, and the phosphor layer 9 is electrically connected to the conductive black matrix 6 via the transparent conductive film 8. , No increase in the charge of the phosphor layer 9 and a decrease in the emission luminance due to the increase in the charge are not caused.

In the example shown in FIG. 1, the pigment layers 7 of the respective colors are used.
In the gap provided between B, 7G and 7R, the black matrix 6 and the transparent conductive film 8 are in contact with each other and are conductive, and such conductive portions are formed on the black matrix 6 between the color pigment layers. It is not necessary that the transparent conductive film 8 be in contact with the black matrix 6 on the side wall portion of the panel 5 to conduct electricity. Further, the transparent conductive film 8 only needs to be in contact with any conductive portion so as to have the same potential, and the black matrix 6 is not necessarily required.
You do not need to be in contact with That is, a deposited film (metal back layer) of aluminum or the like formed on the phosphor layer 9
However, a sufficient effect can be obtained even when the electrical connection is established.

[0021]

Embodiments of the present invention will be described below.

Examples 1 to 6 As a black matrix, a pigment layer of each color of blue, green and red is formed in a dot pattern on an inner surface of a panel of a color cathode ray tube in which a light absorbing layer of a predetermined pattern made of graphite is formed by a known method. Was formed. The formation of the filter layer was performed as described below. That is, as the blue pigment particles, cobalt blue X (particle diameter 0.01 μm to 0.02
μm, 30% by weight, manufactured by Toyo Pigment Co., Ltd.), 0.5% by weight of PVA with ΑDC added as a photoresist, and ammonium salt of a polyacrylic acid copolymer as a polymer electrolyte (trade name: Dispec GA-40, Allied colloid) Company)
Each was dispersed in pure water at a ratio of 0.7% by weight to prepare a blue pigment dispersion. In addition, as a green pigment particle, dipiroxide TM green # 3320 (particle diameter 0.01 μm to 0.02 μm,
30% by weight (Dainichi Seika Co., Ltd.)
2% by weight of C / PV に and 0.7% by weight of sodium salt of acrylic acid (trade name: Dispec N-40) as a polymer electrolyte were dispersed in pure water to prepare a green pigment dispersion. Further, 30% by weight of Fe ₂ O ₃ fine particles (particle diameter 0.01 μm to 0.02 μm) as red pigment particles, ₂ % by weight of ADC / PVA as a photoresist, and ammonium salt of polyoxyethylene alkyl ether sulfate as a polymer electrolyte (HITENOL 08, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) at a ratio of 0.7% by weight in pure water, respectively.
A red pigment dispersion was prepared.

Then, first, the blue pigment dispersion is applied to the inner surface of the panel of the color cathode ray tube maintained at a temperature of 30 ° C., and the panel is rotated at 100 to 150 rpm to shake off the excess pigment dispersion so as to have a constant film thickness. After having a coating layer, the heater temperature
After drying at 120 ° C. for 3 to 4 minutes, an exposure step, a development step, and a drying step were sequentially performed to form a blue pigment layer having a predetermined pattern. Next, a green pigment layer and a red pigment layer were sequentially formed in the same manner as in the step of forming the blue pigment layer.

Next, a dispersion containing ITO or ATO at the ratio (solid content ratio) shown in Table 1 was applied to the entire surface of the filter layer thus formed by spin coating, dried, and dried to obtain a transparent conductive material. A film was formed. Then, the surface resistance of the transparent conductive film thus formed is calculated as
It measured using Loresta IP MCP-T250 (made by Yuka Electronics).

Next, a phosphor layer of each color was formed on the transparent conductive film on the pigment layer of each color by a usual slurry method. The phosphor slurry (suspension)
Used the one having the following composition. That is, as the green phosphor slurry, green phosphor (ZnS: Cu, Δl) 100
g, polyvinyl alcohol 8g, ammonium bichromate
A mixture prepared by mixing and stirring 0.40 g, 0.01 g of a surfactant and 160 g of pure water was used as a blue phosphor slurry, 100 g of a blue phosphor (ZnS: Αg, Cl), and 5 g of polyvinyl alcohol.
g, ammonium bichromate 0.30 g, surfactant 0.01
g and 140 g of pure water were mixed and stirred, and a red phosphor slurry (Y ₂ O ₂ S: Eu) 10
A mixture prepared by mixing and stirring 0 g, polyvinyl alcohol 10 g, ammonium bichromate 0.50 g, surfactant 0.01 g, and pure water 190 g was used.

As a comparative example, a phosphor layer was formed directly on the pigment layer of each color without forming a transparent conductive film.

With respect to the color cathode-ray tubes obtained in the examples and the comparative examples, the luminous brightness of the panel display surface was measured by an ordinary method, and a relative value was calculated with the luminous luminance of the color cathode-ray tube of the comparative example being 100. . Table 1 shows the relative values of the luminance together with the surface resistance of the transparent conductive film described above.

[0028]

[Table 1] As is clear from Table 1, in Examples of the present invention,
By providing a transparent conductive film between the filter layer and the phosphor layer, the light emission luminance of the color cathode ray tube is greatly improved. In particular, the surface resistance of the transparent conductive film is set to 1 × 10
^{When the} resistance is ¹⁰ Ω / cm ² or less, the emission luminance is improved by 5 to 10% as compared with the color cathode-ray tube of the comparative example, and a high-luminance and high-contrast color cathode-ray tube is obtained.

Example 7 A filter in which a light absorbing layer made of graphite and a blue pigment layer, a green pigment layer and a red pigment layer were arranged in a dot pattern on the inner surface of a glass panel of a color cathode ray tube in the same manner as in Example 1. After forming the layers in sequence, ITO was added on the filter layer for 2 hours.
A dispersion liquid containing 0.2% by weight (solid content ratio) of silica (SiO ₂ ) as a binder was applied and dried to form a transparent conductive film. . When the surface resistance value of this transparent conductive film was measured,
The value was 1 × 10 ⁵ Ω / cm ² , and a sufficiently small value of 1 × 10 ¹⁰ Ω / cm ² or less was obtained.

Next, phosphor layers of each color were formed on such a transparent conductive film in the same manner as in Example 1, and the emission luminance of the obtained color cathode ray tube was measured. Assuming that the luminance of the cathode ray tube is 100, a large value of 110 was obtained.

As described above, a large luminance was obtained in Example 7 by adding silica (SiO ₂ ) fine particles as a binder to a dispersion of ITO, thereby obtaining an adhesive strength of a transparent conductive film containing ITO as a main component. This is considered to be due to the fact that the phosphor layer with the filter layer having excellent stability is formed because the retention of the phosphor layer is improved and the holding power to the phosphor is improved.

[0032]

As is apparent from the above description, in the color cathode ray tube having the optical filter layer of the present invention, the chargeability of the surface of the phosphor layer is improved, and the characteristics such as brightness and contrast are greatly improved. I do. Therefore, the industrial value is extremely large.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of an embodiment of a color cathode ray tube according to the present invention.

FIG. 2 is a cross-sectional view showing a main part of a conventional color cathode ray tube.

[Explanation of symbols]

 5 Panel 6 Black matrix 7 Filter layer 8 Transparent conductive film 9 Phosphor layer

Claims (3)

[Claims] 1. A color cathode-ray tube having an optical filter layer on the inner surface of a panel of a face plate and having phosphor layers of respective colors arranged in a predetermined pattern on the outer side thereof, wherein between the filter layer and the phosphor layer A color cathode ray tube comprising a transparent conductive film. 2. The transparent conductive film has a surface resistance value of 1 ×
^2. The color cathode ray tube according to claim 1, wherein the color cathode ray tube has a resistivity of 10 ¹⁰ Ω / cm ² or less. 3. The method according to claim 1, wherein the transparent conductive film contains ITO (indium tin oxide) or ATO (antimony tin oxide) as a main component.
The color cathode ray tube as described.