JPH0574346A - Manufacture of color phosphor screen - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a phosphor film laminate that maintains the linearity of each color phosphor stripe and the uniformity of each stripe interval that can form a phosphor surface of high quality used in a color cathode ray tube. [Structure] A red, green and blue phosphor or a film-like material made of a calcinable organic binder composition in which carbon black is uniformly dispersed is prepared in a
Carbon black, green, carbon black, blue, carbon black are laminated in this order, the linearity of each stripe,
To obtain a film laminate having excellent stripe spacing uniformity. [Effect] It is possible to prevent air bubbles from entering between the films when the colored films are laminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently manufacturing a color phosphor surface for forming a light emitting display surface of a color cathode ray tube (hereinafter abbreviated as CRT).

[0002]

2. Description of the Related Art CRT represented by a cathode ray tube of a television
Is a device that causes an electron beam emitted from an electron gun to collide with the surface of a phosphor film to excite and generate the phosphor, thereby emitting and displaying light. Due to the diversification of various visual devices with the recent development of electronics, monochrome, color, large Are produced in various sizes from super small size.

In the phosphor surface, which is the most important part for exhibiting the performance of such a CRT, especially the color phosphor surface, generally, phosphors of three colors of red, green and blue are arranged in dots or stripes. The phosphor surface is luminescently displayed by an electron beam.

As the manufacturing method, a photo-curing method and a printing method using a shadow mask have been conventionally known. In the former photo-curing method, a slurry in which a phosphor is dispersed in a photo-curing resin is used as C
It is indispensable to use a shadow mask because it is poured into an RT front panel, exposed through a shadow mask, and a phosphor of a predetermined color is fixed at a predetermined place, and then a phosphor surface is formed. There is. In the latter printing method, a color phosphor paste for printing is directly or indirectly printed on the CRT front panel to fix a predetermined color at a predetermined place, and then the binder resin component in the paste is removed by baking. This is a method for producing a phosphor surface by

[0005]

In order to manufacture a CRT by a photo-curing method using a shadow mask, it is essential to use a shadow mask having a fine pattern. The smaller the CRT, the more The higher the resolution of the screen, the more accurate the shadow mask needs to be used, and the difficulty of creating a high-definition shadow mask will increase the cost of materials and production. .. Further, the method for manufacturing a phosphor surface by this method has a drawback that the facility cost is high, it takes much time to recover the phosphor, and the recovery loss is large.

The CRT manufacturing method by the latter printing method is industrially advantageous as compared with the former photo-curing method because the equipment cost is low and the recovery loss of the phosphor is small.
Forming a phosphor surface directly on the curved surface of RT or 0.1 mm
It is necessary to form the following highly accurate stripe pattern on the CRT surface, and it is difficult to produce a compact and high-resolution color phosphor surface in terms of printability. The current situation is that it is not done when the body surface is obtained.

[0007]

In view of such a situation, the present invention does not require a shadow mask, has high-definition RGB stripes required for a high-resolution color phosphor surface, and has a space between RGB stripes. It is an object of the present invention to provide a method for efficiently producing a high quality phosphor surface in which air bubbles are not mixed. The gist of the present invention is to provide a method for manufacturing a phosphor surface used in a color cathode ray tube,
A red, green, and blue phosphor or a film made of a fireable organic binder composition in which carbon is uniformly dispersed, a red layer, a black layer, a green layer, and a black layer so that air bubbles do not enter between the layers. Layer, blue layer, black layer are laminated in this order, a laminate having a predetermined thickness is cut in the thickness direction to form a thin film-shaped cut piece, which is joined to a front panel for a color cathode ray tube, and then fired on a color phosphor surface. It is in the manufacturing method.

Known phosphors can be used for carrying out the present invention, but it is preferable to use phosphors having a small particle size in order to obtain a high-definition stripe pattern. Specific examples of the phosphor include Y ₂ O ₃ S: Eu for red and (ZnCd) S: Cu, A for green.
For 1 and blue, ZnS: Ag and the like can be mentioned, and it is preferable to use one having a particle size of about 3 to 10 μm. As the carbon black, known carbon blacks can be used, and those having a small particle size are preferable in order to obtain a high-definition stripe pattern. Specific examples of the carbon black include high-purity graphite and the like, and it is preferable to use one having a particle size of about 2 to 10 μm.

The organic binder used for producing a film-like material in which the phosphor is dispersed is a resin having excellent baking properties, and the phosphor or carbon black can be uniformly dispersed and a uniform film. There is no particular limitation as long as a film-like material having a thickness can be obtained. A film containing a phosphor pigment, which is produced by using an organic binder that causes a baking residue, may cause black spots during baking in manufacturing a CRT, or may cause a CRT.
It is not preferable because it will shorten the life significantly.

Specific examples of the organic binder include, for example, cellulose resins, vinyl alcohol resins, and methacrylate resins. Among these, in order to improve the baking property of the phosphor pigment-containing film. It is preferable to use a methacrylate resin as the binder. In order to produce a phosphor pigment-containing film, a solution of an organic binder in which the phosphor pigment is dispersed,
It is sufficient to coat the substrate using a coating method such as a roll coater method or a screen printing method, which has a good thickness controllability of the obtained film, remove the solvent and dry, and then peel off the film. A plate, a stainless plate or the like can be used, and a stainless belt is preferably used for continuous continuous film production.

In order to form a film laminate using the four pigment-containing films obtained as described above, the order of the red layer, the green layer and the blue layer is the basic constitutional unit, and the color of the obtained phosphor surface is In order to prevent bleeding and ensure the separation of the respective colors, it is preferable to interpose a black film layer between the respective color layers. The thickness of these films is preferably in the range of 5 to 30 .mu., Considering that the image quality of the image on the phosphor surface is greatly affected and that the film is easy to make.

The surface of the pigment-containing film used in the present invention is formed with subtle unevenness, and it is necessary to prevent bubbles from being entrapped between the laminated films when laminating the film. It is impossible to remove the bubbles later in the film laminate in which the bubbles are caught between the laminated films. The cut pieces obtained by cutting the laminated film containing air bubbles in a thin film shape in the thickness direction are aggregates of stripes made of pigment, but the stripes are bent at the air bubbles and the stripe width is not uniform. The color phosphor surface obtained by firing such a thin-film cut piece cannot be used as a CRT capable of obtaining an image of uniform image quality.

In order to form a phosphor surface having the linearity of each pigment stripe on the phosphor surface, the width uniformity, and the pitch interval uniformity without causing the above-mentioned inconvenience, a fluorescent pigment-containing film as a raw material thereof is prepared. It is necessary to prevent air bubbles from being entrapped between the layers in laminating, and to maintain good parallelism of the laminated film. For that purpose, when laminating colored films, an adhesive is applied between the films and pressed by rollers so as not to entrap air bubbles between the films, or as shown in FIG. 1, two pressing plates under vacuum are used. It is preferable to use the lamination method under the vacuum atmosphere used. In particular, two parallel pressing plates (composed of the lifting table 2 and the fixed base 3)
Laminated film formed by the film laminating method under a vacuum atmosphere using, the parallel adhesion of each film is kept good, even when laminated in the state where there is a gap between the films, laminated By returning the film to atmospheric pressure, these voids are erased all at once, and the uniformity of the stripe gap can be ensured.Therefore, the color phosphor screen made using the thin film cut pieces cut out from this laminated film is extremely high. It can be of high image quality. As a method for applying a vacuum, it is preferable to create a vacuum state using a generally known vacuum pump, but the method is not limited to this.

As a cutting method for obtaining a thin film cut piece from the colored film laminate, for example, a cutting method using a microtome may be mentioned, and the film thickness thereof is usually 10.
The thing of about 60 μ is used. The obtained thin film-shaped cut pieces are bonded or pressure-bonded to the front panel for color cathode lines and then baked to obtain a color phosphor surface. As a method for adhering the thin-film cut pieces to the front panel, for example, a water-soluble adhesive such as water glass or polyvinyl alcohol may be applied onto the front panel, and the thin-film cut pieces may be bonded, dried and fixed. Further, as a pressure bonding method, for example, the thin film cut piece may be pressed and fixed on a glass substrate with a rubber roller or the like so that no bubbles remain between the substrate and the thin film cut piece.

In the present invention, by interposing a carbon layer between each phosphor layer, color bleeding at the boundary of red, green and blue colors is prevented, separation of each color is ensured, and it is reproduced in a cathode ray tube. This is to improve the contrast of the image.

[0016]

The present invention will be described in more detail with reference to the following examples. [Example 1] A butyl cellosolve solution of acrylic copolymer of 99 wt% isobutyl methacrylate and 1 wt% methacrylic acid was added to 100 parts by weight of acrylic copolymer red.
Green and blue phosphor pigments were added at a ratio of 330 parts by weight, and butyl cellosolve was used to adjust the viscosity to 10,000 cps to prepare three types of phosphor pigment resin compositions. Also,
Carbon black was added to a butyl cellosolve solution of an acrylic polymer so as to be 35 wt% to prepare a black pigment resin solution. Each of the four types of resin solutions prepared as described above was applied onto a glass plate and dried at 80 ° C. to form four types of films with a film thickness of 20 μm.

A device as shown in FIG. 1 was prepared and operated as follows. The inside of the vacuum chamber 1 was evacuated by a vacuum pump 9 through a vacuum suction hose 7 through a vacuum suction port 10. The lifting table 2 can be lifted and lowered by the motor 8 and the lifting mechanism. As the lifting mechanism, for example, a ball screw, a wire, a belt and a combination thereof are used. The fixed base 3 is fixedly attached to the pedestal 6, and its surface is kept parallel to the fixed base 3. The film sample A 4 is temporarily fixed to the lower surface of the fixed base 3 with double-sided tape or the like. The film sample B 5 is placed on the lifting table 2. At least one of the film sample A 4 and the film sample B 5 was coated with a solvent to secure the adhesiveness between them. The elevating table 2 is lifted and pressure-bonded to the fixed base 3 to stack the film sample A and the film sample B, which is held for a certain period of time, and the elevating table 2 is lowered.
After the vacuum was released, a new film sample was placed on the lifting table and the same operation as above was repeated to form a film laminate. The adhesive surface between the vacuum chamber 1 and the pedestal 6 may be covered with rubber packing or the like. A red phosphor pigment-containing film having a surface coated with butyl cellosolve and a black pigment film were set in the above apparatus, and the elevating mechanism was operated under vacuum to bond the two films. Subsequently, a green pigment film having its adhesive surface moistened with a solvent was set and bonded to the above laminated film and dried. By the same operation as described above, a laminated film having a thickness of 30 mm, which is a repeating unit having one unit of red film / black film / green film / black film / blue film / black film, was obtained. This laminated film has a thickness of 30 using a microtome.
A μ-shaped thin piece was cut out. Microscopic observation of this cut piece showed no air bubbles between the layers. This thin piece was adhered to a glass plate by Povar, and then baked at 400 to 450 ° C. to decompose unnecessary resin components to form a color phosphor surface. The linearity and width uniformity of each stripe on the surface of the obtained color phosphor were good, and no distortion due to bubbles was observed.

As described above in detail, according to the present invention,
Since bubbles are not mixed between the stripes, a high-definition RGB stripe can be formed and a high-resolution phosphor surface can be obtained. Therefore, it can be applied to a small CRT which has been difficult to put into practical use in the past.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

[Explanation of symbols]

 1 Vacuum Chamber 2 Lifting Table 3 Fixed Base 4 Sample A 5 Sample B 6 Stand 7 Vacuum Suction Hose 8 Motor 9 Vacuum Pump 10 Vacuum Suction Port

Claims (3)

[Claims] 1. A method for producing a phosphor surface for use in a color cathode ray tube, comprising a film made of four kinds of calcinable organic binder compositions in which red, green and blue phosphors or carbon black are uniformly dispersed. The layered product is sequentially laminated in order of a red layer, a black layer, a green layer, a black layer, a blue layer, and a black layer so that air bubbles do not enter between the layers, and a laminate having a predetermined thickness is cut in a thickness direction. A method for manufacturing a color phosphor surface, which comprises bonding the cut pieces in the form of a thin film to a front panel for a color cathode ray tube and then firing. 2. A film-like material composed of four kinds of calcinationable organic binder compositions in which red, green, and blue phosphors or carbon black are uniformly dispersed, respectively, is laminated in a vacuum. Item 2. A method for producing a color phosphor surface according to item 1. 3. The method for producing a color phosphor surface according to claim 1, wherein parallel pressing plates are used to maintain the parallelism of the laminated films when laminating the films.