JPH08106859A - Color cathode-ray tube - Google Patents

Abstract

PURPOSE: To improve luminance and contrast by providing a color filter layer consisting of each color pigment of green, blue and red between a face plate and a white light emitting phosphor film. CONSTITUTION: Each color filter 3, 4, 5 consisting of green, blue and red pigments and a black matrix layer 2 are alternately arranged on the face plate 1 of a color cathode-ray tube. A white light emitting phosphor film 6 as a light surface is formed on the whole back surface. An Al thin film is formed on the back surface of the film 6 by vacuum evaporation. In such a cathode ray tube, not only the manufacturing cost can be suppressed low because of the simple structure of the phosphor screen, but also the luminance and contrast are enhanced. As organic colored pigments used for the formation of the color filter layers, copper phthalocyanine green G and Y for green, copper phthalocyanine blue and indanthrone blue for blue, and brilliant carmin 6B and lake red C for red can be used.

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 such as a color cathode ray tube or a color display tube, and more particularly to a high brightness and high contrast color cathode ray tube which can be manufactured at low cost.

[0002]

2. Description of the Related Art Many conventional techniques have been proposed for the purpose of increasing the contrast and improving the brightness of color cathode ray tubes. As one of the methods, a method of using a so-called pigmented phosphor, in which a coloring pigment having a body color similar to the emission color of the phosphor is attached around the phosphor, has been widely adopted in general. This method has a drawback that the contrast is improved when the pigment concentration is increased, but the brightness of the phosphor is lowered, and it is difficult to achieve both high contrast and high brightness.

There has also been proposed a method of providing a colorant layer (color filter layer) having a body color similar to the emission color of the phosphor film between the face plate and the phosphor film. As a known example relating to this, for example, US in which a colored layer such as a colored gelatin layer is provided between a face plate and a phosphor film
P2,577,368. Further, a pigment layer having a color tone similar to the fluorescence emitted by the phosphor layer is interposed between the face plate and the phosphor film.
It is proposed in Japanese Patent No. 587-14589. Although these methods are expected to improve in principle, in practice, various problems occur (in the former, the components of the colorant layer decompose or release gas in a high vacuum. In the latter, the pigment layer causes Inhomogeneity causes unevenness, and since the film thickness is large, the external light reflectance is improved, but the brightness is significantly reduced.)

Similar proposals for developing these are disclosed in Japanese Patent Laid-Open Nos. 64-7457 and 5-2667.
No. 95 publication. In these, two methods are disclosed as a method for forming a color filter layer and a phosphor film. One is a method of forming green, blue, and red color filter layers in advance and then forming green, blue, and red phosphor films (Japanese Patent Laid-Open No. 64-7457). This has a problem that the number of steps is doubled as compared with the conventional method, the manufacturing line needs to be greatly expanded, and the cost is increased. Two
The second method was made to solve this drawback.For example, a coating film for forming a green color filter layer and a coating film for forming a green light emitting phosphor film are overcoated, and then exposed and developed. This is a method in which a green color filter layer and a green light emitting phosphor layer are formed as a set, and this is repeated for blue and red (JP-A-5-266795). However, in this method, for example, a green color filter layer and a green light-emitting phosphor layer are formed by exposing and developing after coating a coating film for forming a green color filter layer and a coating film for forming a green light-emitting phosphor film. When forming a set and then forming a set of a blue color filter and a blue light emitting phosphor, a blue color filter is formed on the set film of the green color filter layer and the green light emitting phosphor layer already formed on the face plate. Since the coating film for forming the layer and the coating material for forming the blue light emitting phosphor are applied in an overlapping manner, there is a problem that the blue pigment or the blue coloring phosphor is submerged between the particles of the green phosphor formed in advance. In this way, if the blue pigment is mixed in the green-emitting phosphor, not only the emission efficiency of the green-emitting phosphor due to the electron beam is absorbed by the blue pigment and the emitted green light becomes blue pigment. It is absorbed and the brightness decreases. Further, if the blue light emitting phosphor is mixed between the particles of the green light emitting phosphor, there is a problem that the blue light emission is also mixed and observed from the place where only the green light emission is originally made and the color purity is lowered. .

[0005]

SUMMARY OF THE INVENTION The present invention has been made as a solution to the problems of the prior art proposed for the purpose of increasing the contrast and improving the brightness of a color cathode ray tube.

[0006]

The present invention provides a color cathode ray tube having a fluorescent surface on the inner surface of a face plate, and a color filter layer comprising green, blue and red color pigments between the face plate and the phosphor film. And a white light emitting phosphor is formed on the entire surface as the phosphor film. This color cathode ray tube also includes a color cathode ray tube in which green, blue, and red color filter layers are formed at predetermined positions in a black matrix.

In a monochrome display tube, a monochromatic (not white) color filter layer is formed between a face plate and a phosphor film, and a phosphor film emitting the same color as the color is formed on the entire surface of the color filter layer. The forming technique has been known (Japanese Patent Laid-Open No. 64-7457), but there is no suggestion about the constitution of the present invention, and it is of course impossible to find the studied example in the past.

The present invention is a new structure of the color cathode ray tube and has a great breakthrough, and it is an industrially extremely useful and useful technique.

The structure of the color cathode ray tube of the present invention, particularly the structure of the phosphor screen, will be described below in comparison with the conventional structure. As shown in FIG. 2, the structure of the phosphor screen of the conventional color cathode ray tube is as follows: the face plate (1) has phosphor layers (7), (8 '), (9') for green light emission, blue light emission, and red light emission. ) (Here, in the blue light emitting phosphor layer (8 ′) and the red light emitting phosphor layer (9 ′), so-called color pigment particles having the same body color are attached around each phosphor particle, that is, Pigmented phosphors) and black matrix layers (2) are arranged alternately, and an aluminum thin film (not shown) is formed on the back surface of these by vacuum deposition. still,
Each phosphor film and the black matrix film are produced by the procedure shown in FIG. 4 (however, in the prior art shown in FIG. 2, among the phosphors in the figure, a blue light emitting phosphor and a red light emitting phosphor are selected. Is a pigment pigment particles having the same body color are attached around each phosphor particle).

The face plate and the phosphor layer (not the pigmented phosphor. The green light emitting phosphor layer (7), the blue light emitting phosphor layer (8) and the red light emitting phosphor layer (9) are the black matrix layer ( FIG. 3 shows the structure of the phosphor screen in which a color filter layer is provided between (2) and (which are arranged alternately). As is clear from this figure, the color of each color filter and the emission color of each phosphor are designed to have a one-to-one correspondence. As a matter of course, if this correspondence is broken, the color purity is lowered. As a process for manufacturing this type of phosphor screen, in the procedure shown in FIG. 4, after the black matrix is prepared, each color filter layer is repeatedly formed by applying, exposing, and developing three times before forming the phosphor film ( (Japanese Patent Laid-Open No. 64-7457), or in the phosphor film forming step, a color filter layer and a phosphor film for each color are set as a set, and the coating, exposure, and development are repeated three times (Japanese Patent Laid-Open No. 5-266795). Gazette).

On the other hand, the structure of the fluorescent screen of the color cathode ray tube of the present invention is as shown in FIG. 1, in which the color filter layers (3) and (4) made of green, blue and red pigments are formed on the face plate (1). ), (5) and the black matrix layer (2) are alternately arranged, and a white light-emitting phosphor film (6) as a light source is formed on the entire back surface thereof, which is very simple. An aluminum thin film (not shown) is formed on the back surface of the white light emitting phosphor film by vacuum deposition.

The color cathode ray tube of the present invention is a color cathode ray tube of high brightness and high contrast as well as a low manufacturing cost due to the simple structure of the phosphor screen. The technical features thereof are shown below in comparison with the conventional color cathode ray tube.

(1) The contrast is improved by the effect of the color filter as compared with the conventional color cathode ray tube in which the color filter layer is not provided.

(2) In a conventional color cathode ray tube, a phosphor film is formed by using a water-soluble photosensitive resin such as polyvinyl alcohol (PVA) / ammonium dichromate (ADC) as a binder, and the phosphor is added thereto. It was produced by repeating the coating, drying, exposing, developing and drying of the dispersed slurry three times. This method has a large drawback that it requires a large number of steps and a large amount of water and heat energy to increase the manufacturing cost, and in addition, the imperfections of the phosphor film (“dot or Striped fall "
, Or "Pinhole") decrease in brightness,
Degradation of color purity due to mixing (color mixing) of other color phosphors into the phosphor film of a certain color produced earlier due to problems in the process of sequentially forming phosphor films of three colors one by one, binder Brightness decrease of phosphor due to firing (according to the inventor's knowledge, a red-emitting phosphor based on yttrium oxyl sulfide is influenced by residual chromium derived from ADC as a sensitizer, and zinc sulfide It has been experimentally confirmed that the base green and blue light emitting phosphors are affected by the baking residue derived from PVA as a photosensitive resist), but there are some drawbacks. In the color cathode ray tube of the invention, since the white light emitting phosphor only needs to be applied once on the color filter,
The phosphor film is uniform and free from defects. As a matter of course, since the white light emitting phosphor is used, there is no color mixture which has been a problem in the past. Further, since the phosphor film is formed on the entire surface, it is not necessary to define the phosphor film forming location using a photosensitive resin as in the conventional case, and therefore, the binder of the phosphor slurry needs a function of photosensitivity. Disappeared
Expands the range of materials that can be used as binders. In other words, an organic polymer material that does not leave ash even if the baking (baking) temperature is low, or an inorganic material such as water glass that does not produce ash even when baked can be widely used.

(3) Since the phosphor film can be formed smoothly,
When the aluminum film is vapor-deposited thereon after filming, an aluminum film having a high reflectance can be formed, so that the brightness is improved.

In the present invention, the color filter layer is formed by applying a photosensitive resin liquid in which a pigment is dispersed, exposing it through a shadow mask, and removing the unexposed portion by development. , A method of repeating with blue and red color pigments, applying a photosensitive resin solution and then exposing through a shadow mask, removing the unexposed areas by development, and dyeing the exposed areas with green and blue. In addition to the method of repeating each color of red and red, a method of attaching pigment particles by electrodeposition or an electrophotographic technique can be used.

Inorganic color pigments used for forming the color filter layer of the present invention include green as chromium green, zinc green, viridian, cobalt green,
Ultramarine blue, cobalt blue, cerulean blue, manganese blue, etc. can be used for blue such as chromium oxide and cobalt / chromium green, and red iron such as red iron oxide, cadmium red, red lead, chrome vermillion, and cadmium vermillion can be used.

Organic color pigments used for forming the color filter layer of the present invention include phthalocyanine green G and phthalocyanine green Y for green, phthalocyanine blue and indanthrone blue for blue, and the like.
In red, Brilliant Carmine 6B, Rake Red C,
Quinacridone magenta, condensed azo red BR, benzimidazole red HF2B and the like can be used.

The particle size of the pigment varies depending on the kind of the pigment, but is preferably in the range of 0.2 μm (200 nm) to several nm. This is because if the thickness is 0.2 μm or more, the hiding power becomes strong and the requirement of the color filter layer of the present invention that light is transmitted is not satisfied, while if the thickness is nm or less, aggregation of particles occurs and it becomes difficult to disperse in the slurry. .

The thickness of the color filter is
Although it depends on the pigment concentration in the color filter, it is necessary that at least two layers of pigment particles are arranged in the light transmission direction, and a range of 10 to 500 nm is preferable. 10n
If it is thinner than m, the coloring degree is insufficient, while if it is thicker than 500 nm, the light reflection on the surface of the pigment is increased and the emission color is attenuated to be dark.

Further, in order to increase the stability of these color pigments, it is possible to coat these pigments with a transparent inorganic coating or to coexist with an inorganic material, if necessary. Examples of such a treatment method include the following. (1) A method of adding an inorganic acid such as sulfuric acid or metallic lead such as zinc sulfate to an aqueous suspension of a color pigment and water glass to coat the surface of the pigment with silica (2) Mixing the color pigment and an alumina sol Then, the method of coating the surface of the pigment with alumina hydrate (3) While coexisting the coloring pigment with the alkoxysilane,
A method of obtaining a colored gel by hydrolyzing and polycondensing an alkoxysilane to obtain a colored gel. (4) The coloring pigment is oxyfluoride glass (PTFP).
Glass), which is obtained by melting and mixing in a glass melt, which has a low melting point and high organic molecule solubility, and is then cooled and ground.

In the present invention, as a method for forming a phosphor film, in addition to the slurry method (in which the phosphor is made into an aqueous slurry together with a binder), various dusting methods (for example, Japanese Patent Publication Nos. Sho 48-14498 and Sho 57). -20651
Gazettes) and electrophotography (for example, Japanese Patent Publication No. 49-227
No. 76, USP 5,093,217, etc.) can be used. Here, in the present invention, since the phosphor film is completed by one film forming process, the process is simple and various dusting methods and electrophotographic methods can be easily performed in addition to the conventionally widely used slurry method. It is also a major feature that it can be applied. A method of spray-applying the slurry can also be applied in the present invention.

As the white light emitting phosphor, a green light emitting phosphor (copper, which has been conventionally used for a color cathode ray tube) is used.
A mixture of gold, aluminum activated zinc sulfide), blue light emitting phosphor (silver activated zinc sulfide) and red light emitting phosphor (europium activated yttrium oxysulfide), or white that has been used for black and white cathode ray tubes. A luminescent phosphor (for example, a mixture of silver activated zinc sulfide and silver activated zinc cadmium sulfide) can be used.

The particle size of the phosphor is several μm to several tens μ.
The range of m is preferable. If it is above this range, the brightness tends to be saturated, while if it is below this range, the light scattering tends to increase and the brightness tends to decrease, which is not preferable.

The thickness of the phosphor film is in the range from one or more layers of phosphor particles arranged in the light transmitting direction to several layers (generally, 2 to 4 expressed as an average coating amount after drying). .5
(about mg / cm ² ) is preferable. If it exceeds this range, the brightness will be saturated, which is meaningless. On the other hand, if the thickness is less than this range, a uniform film thickness cannot be secured and sufficient brightness cannot be obtained.

Since these phosphor films may be formed on the entire surface, they have been used for imparting photosensitivity in the slurry method which is conventionally used in the production of color cathode ray tubes, for example, from PVA and ADC. It is not necessary to use a photosensitive resin as a binder.

Green-emitting phosphors (copper, gold, aluminum-activated zinc sulfide) and blue-emitting phosphors (silver-activated zinc sulfide) are produced by baking residues of PVA, and red-emitting phosphors (europium-activated yttrium oxysulfide) are used. It is known that chromium in the ADC lowers the luminance, but in the present invention, since the photosensitivity is not required as the binder for forming the phosphor film, the ADC can be not used, and the combustion residue as the binder can be left. It is also a big effect that a resin with less amount can be used.

As the resin usable in the present invention, acrylic resin, polyethylene oxide, carboxymethyl cellulose, methyl cellulose, hydroxypropyl cellulose, cellulose nitrate carboxymethyl ether,
There are aqueous resins such as polyvinyl alcohol and its derivatives and polyvinyl butyral. It is also possible to use an inorganic binder such as potassium silicate which has been conventionally used for producing a black and white cathode ray tube. As such an inorganic binder, a hydrolyzed / polycondensed product of alkyl silicate, silica, alumina sol, or the like can be used alone or in combination with another binder.

[0029]

EXAMPLES The present invention will now be described in detail based on examples.

First, a black matrix was formed on the inner surface of the face plate by a conventionally known method. That is,
A water-soluble photoresist containing polyvinylpyrrolidone (PVP) and bisazide as the main components is applied to the inner surface of the face plate of the color cathode ray tube, and exposure, development and drying are repeated three times through a shadow mask to obtain a conventional color cathode ray tube. The green, blue, and red light-emitting phosphor layer formation-scheduled portions are formed into stripe-shaped or dot-shaped photo-cured films, and graphite slurry is applied and dried on this to fix graphite, and then with a sodium hypochlorite aqueous solution. The photocured film was removed by etching together with the graphite film adhered thereon to expose the portion where the phosphor layer was to be formed, thereby forming a patterned black matrix.

The PVA / AD containing cobalt green fine particles (average particle diameter: about 100 nm) was first added to the face plate with the black matrix thus formed.
C Aqueous slurry is applied and dried, exposed through a shadow mask, developed with water, and dried to form a green color filter layer (average film thickness: 350 nm) in a portion of the conventional color cathode ray tube where a green light emitting phosphor layer is to be formed. )made. This operation is repeated with a blue pigment and a red pigment, and a blue color filter layer (average film thickness: 300 nm) and a red color are respectively formed in the blue light emitting phosphor layer forming planned portion and the red light emitting phosphor layer forming planned portion in the conventional color cathode ray tube. Color filter layer (average film thickness: 200 nm) was prepared. As blue and red pigments, blue is cobalt blue (average particle size:
About 100 nm), and red was cadmium red (average particle size: about 50 nm).

The green matrix (ZnS: Cu) and the blue-emitting phosphor (Zn) which are commercially available as phosphors for color cathode ray tubes are provided on the face plate with the black matrix and the three color filters thus formed.
30% by weight of a mixture of S: Ag) and a red light emitting phosphor (Y ₂ O ₂ S: Eu), an acrylic resin emulsion as a binder (Primal C-72 [product of Rohm and Haas Company], solid content 45%). As a solid content of 3 wt% and a thickening agent of high molecular weight polyethylene oxide (PEO,
An aqueous slurry containing 0.5% of a steelmaking chemical product) and a small amount of a surfactant was injected, and a white light emitting phosphor layer was formed by sedimentation coating using a spin coater. Excess binder and water were removed and then dried, and then filming was performed by a conventional method using a filming agent containing an acrylic resin as a main component. It should be noted that the filming could be adopted in either emulsion filming or lacquer filming.

After these steps, a color cathode ray tube was manufactured through steps such as aluminum vapor deposition, panel baking, attachment of a funnel and sealing.

The brightness of the color cathode ray tube obtained by this method was measured by an illuminometer (Foot Lambert meter) to find that it was 39% as compared with a conventional color cathode ray tube having a pigmented phosphor screen without a color filter. It was improved by 10% as compared with a color cathode ray tube having a fluorescent screen. In addition, the external light reflectance (the light emitted from a white light bulb is at a certain angle to the face plate, the intensity of the reflected light at a certain angle is measured with an illuminometer, and is represented by the ratio of the reflected light to the irradiation light) 4 for a color cathode ray tube without a color filter and having a pigmented phosphor screen
It was 0% and 37% in the conventional color cathode ray tube having the phosphor screen with the color filter, whereas it was 10% in the color cathode ray tube of the present invention.

[0035]

As described above, the color cathode ray tube of the present invention provides a color cathode ray tube with greatly improved brightness and contrast.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of a phosphor screen of a color cathode ray tube according to the present invention.

FIG. 2 is a cross-sectional view showing a structure of a phosphor screen of a conventional color cathode ray tube having a pigment-containing phosphor screen without a color filter.

FIG. 3 is a sectional view showing a structure of a phosphor screen of a conventional color cathode ray tube having a phosphor screen with a color filter.

FIG. 4 is a block diagram showing a procedure for manufacturing a phosphor screen of a conventional color cathode ray tube.

[Explanation of symbols]

 1 Face Plate 2 Black Matrix Layer 3 Green Color Filter Layer 4 Blue Color Filter Layer 5 Red Color Filter Layer 6 White-Emitting Phosphor Layer 7 Green-Emitting Phosphor Layer 8 Blue-Emitting Phosphor Layer 8'Blue-Emitting Phosphor Layer (with Pigment) ) 9 red light emitting phosphor layer 9'red light emitting phosphor layer (with pigment)

Claims (2)

[Claims] 1. A color cathode ray tube having a phosphor screen on the inner surface of a face plate, wherein a color filter layer comprising green, blue and red color pigments is provided between the face plate and the phosphor film. Is a white light emitting phosphor, and is a color cathode ray tube. 2. The color cathode ray tube according to claim 1, wherein each of the color filter layers is formed at a predetermined position of a black matrix.