Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Including a second component containing structurally defined...
Reexamination Certificate
1999-12-01
2004-03-02
Le, H. Thi (Department: 1773)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Including a second component containing structurally defined...
C428S330000, C106S286600
Reexamination Certificate
active
06699580
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a dispersion liquid composition being used for preparation of black matrix of a display surface of a display device such as a cathode ray tube, or similar device. In addition, the present invention relates to a display device such as a cathode ray tube, a plasma display panel (PDPs) and a field emission display (FED), and manufacturing method thereof.
BACKGROUND ART
In general, on an interior surface of a glass panel of a faceplate of a color cathode ray tube, a blue-emitting phosphor layer, green-emitting phosphor layer and red-emitting phosphor layer are disposed in dots or in stripes. By impinging an electron beam on the respective phosphor layers, the respective phosphors emit the respective colors to result in display of images.
On such a display surface of a color cathode ray tube, to enhance contrast through absorption of light from other than the respective phosphors, among phosphor dots or phosphor stripes that form adjacent pixels, a light absorption layer (black layer) is disposed as black matrix. Formation of the light absorption layer is performed, for example, in the following way. On an interior surface of a glass panel, photo-resist is coated, the coated photo-resist layer is exposed to a ultra-violet light beam through a shadow mask, and the exposed photo-resist layer is developed to form a resist pattern consisting of dots or stripes. Thereafter, thereon a dispersion liquid of a light absorptive substance is coated to bind, then with a decomposing agent such as hydrogen peroxide water, the resist layer and the layer of the light absorptive substance formed thereon are dissolved and separated to form the light absorption layer.
As the dispersion liquid of the light absorptive substance, as disclosed in Japanese Patent Application KOKOKU Publication No. 51(1976)-5856, water suspension that contains approximately 10% by weight of fine particles of graphite, approximately 1% by weight of a binder such as water glass, and a dispersing agent such as carboxymethyl cellulose is known.
However, in the display surface thereon the light absorption layer of which main component is graphite is formed, the light absorptive layer suppresses effectively diffusive reflection of ambient light but can not suppress sufficiently specular reflection thereof.
That is, in the light absorption layer that is formed by coating a dispersion liquid including graphite to bind, as shown in
FIG. 11A
, of light
52
incident from outside of the panel (glass panel)
51
, the diffuse reflection light
54
that is approximately homogeneously reflected in all direction at an interface of the panel
51
and the light absorption layer
53
can be effectively reduced. However, as shown in
FIG. 11B
, the light
55
reflected specularly according to the law of reflection at the interface of the panel
51
and the light absorption layer
53
can not be reduced sufficiently. Accordingly, there was a problem that the ambient light such as fluorescent lamp is added on the display surface to cause a difficulty in observing the display surface.
The present invention is carried out to solve such problems. An object of the present invention is to provide a dispersion liquid composition for black matrix that enables to form a light absorption layer that, in a display surface of a display device such as a cathode ray tube, remarkably reduces reflectivity at the interface between a light absorption layer and a panel to make the ambient light less additive.
In addition, another object of the present invention is to provide a display device of which interface between the light absorption layer that is black matrix and the panel is reduced in reflectivity to make the ambient light less additive, and a manufacturing method thereof.
DISCLOSURE OF THE INVENTION
A first aspect of the present invention relates to a dispersion liquid composition for preparation of black matrix. The dispersion liquid composition comprises manganese oxide of an average particle diameter of 50 to 2000 nm, or solid solution of manganese oxide and ferric oxide of which an average particle diameter is in the range of 50 to 2000 nm and manganese content is in the range of 15 to 70% by weight, at least one kind of dispersing agent selected from a group of water soluble acrylic resin, sodium salt, ammonium salt or potassium salt of water soluble acrylic resin, sodium salt, ammonium salt or potassium salt of polycarboxylic acid or lignin sulfonic acid or bisphenol sulfonic acid, and water or an organic solvent compatible with water, respectively.
A second aspect of the present invention relates to a display device. A display device comprises a transparent panel, a light absorption layer disposed on an interior surface of a panel as black matrix, and phosphor layers disposed on a rear surface side opposing to the panel with respect to the light absorption layer. The light absorption layer contains, as the main component thereof, manganese oxide of an average particle diameter of in the range of 50 to 2000 nm, or solid solution of manganese oxide and ferric oxide of which average particle diameter is in the range of 50 to 2000 nm and manganese content is in the range of 15 to 70% by weight.
A third aspect of the present invention relates to a manufacturing method of the display device. The manufacturing method comprises a step of forming a light absorption layer as black matrix on an interior surface of a transparent panel, and a step of forming phosphor layers on the rear surface side opposing to the panel with respect to the light absorption layer. In the step of forming the light absorption layer, a dispersion liquid is coated on the interior surface of the panel to bind. Here, the dispersion liquid contains manganese oxide of an average particle diameter of in the range of 50 to 2000 nm, or solid solution of manganese oxide and ferric oxide of which average particle diameter is in the range of 50 to 2000 nm and manganese content is in the range of 15 to 70% by weight, at least one kind of dispersing agent selected from a group of water soluble acrylic resin, sodium salt, ammonium salt or potassium salt of water soluble acrylic resin, sodium salt, ammonium salt or potassium salt of polycarboxylic acid or lignin sulfonic acid or bisphenol sulfonic acid, and water or a mixed solvent of water and an organic solvent compatible with water.
In the present invention, as the light absorption substance, manganese oxide of which average particle diameter is controlled in the range of 50 to 2000 nm, or solid solution of manganese oxide and ferric oxide of which average particle diameter is controlled in the range of 50 to 2000 nm is employed. Manganese oxides can be manganese dioxide (MnO
2
), dimanganese trioxide (Mn
2
O
3
), trimanganese tetroxide (Mn
3
O
4
), dimanganese heptoxide (Mn
2
O
7
), or similar compound. In particular, manganese dioxide is preferably employed.
In addition, manganese oxide or the solid solution of the manganese oxide and ferric oxide having such an average particle diameter is preferably included in the ratio of 0.5 to 60% by weight with respect to the total dispersion liquid, more preferable to be included in the ratio of 5 to 35% by weight. When the content of manganese oxide or the solid solution of manganese oxide and ferric oxide is less than 0.5% by weight of the total dispersion liquid, as the black matrix of the display device such as cathode ray tube, a light absorption layer (black layer) having sufficient light shielding property can be formed with difficulty. On the other hand, when the content exceeds 60% by weight, viscosity of the dispersion liquid becomes too high to coat uniformly on the panel even if an additive that will be described later is added.
Further, as a solid solution of manganese oxide and ferric oxide, one of which manganese content is more than 15% by weight can be employed. In particular, one of which manganese content is in the range of 15 to 70% by weight is preferably employed. The solid solution of which manganese content is less than 15% b
Fukuda Masaru
Inubushi Yoichi
Ito Takeo
Nakazawa Tomoko
Oyaizu Tsuyoshi
Kabushiki Kaisha Toshiba
Le H. Thi
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