KR20000074916A - Method manufacturing phosphor layer for color CRT - Google Patents

Abstract

PURPOSE: A method for forming a fluorescent film of a color cathode ray tube is provided to improve the flatness level of a metal reflecting film which again reflects a second electron beam, being reflected in a rear direction after striking a fluorescent film, in a front direction of a panel. CONSTITUTION: A method for forming a fluorescent film of a color cathode ray tube comprises the steps of; forming a white fluorescent substance layer(7) containing a ZnS:Ag(Zn,Cd)S:Cu, a white fluorescent substance, on an upper surface of three color fluorescent substance layers(3R,3G,3B); consecutively coating prewet solution(6) and a Lacquer-Filming film(5) on an upper surface of the white fluorescent substance layer(7) to flat a metal reflecting film(4); forming the metal reflecting film(4) by vacuum deposition of aluminium on an upper surface of the Lacquer-Filming film(5); and forming an air gap between the white fluorescent material layer(7) and the metal reflecting film(4) by thermally decomposing the prewet solution(6) and the Lacquer-Filming film(5) under high temperature. Accordingly, it is possible to embody the increase of luminance by the re-reflection of a second electron beam and radiation of the white fluorescent substance.

Description

Method for forming fluorescent film of color cathode ray tube {Method manufacturing phosphor layer for color CRT}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent film of a color cathode ray tube. More particularly, the present invention relates to a color cathode ray tube for flatly forming a metal reflective film that strikes a fluorescent film and reflects a secondary electron beam reflected back to the front side of the panel. A method of forming a fluorescent film.

As is well known, color cathode ray tubes are the most widely used display devices for observation of oscilloscopes and radars as well as television receivers.

The color cathode ray tube is a device that converts image information received as an electrical signal into visual information through a fluorescent film.

That is, the activated electron beam on the rear side strikes the fluorescent film located inside the panel to generate visible light, and the visible light is emitted to the front of the panel to recognize the color image, and much effort has been made to realize an excellent image.

FIG. 1 illustrates a fluorescent film of a conventional color cathode ray tube for implementing a color image, wherein a black matrix 2 as an external light absorbing layer is formed from an inner surface of the panel 1, and three color phosphor layers 3R (3G) (3B) forming pixels. ) And the metal reflective film 4 which reflects the light reflected back to the rear side after the fluorescent film strike in the front direction of the panel 1 to improve the brightness characteristic of the screen.

Here, in order for the metal reflective film 4 to have a mirror-like light reflection effect, there must be a certain gap between the three-color phosphor layers 3R (3G) and 3B, and the surface thereof must be flat, and the three-color phosphor When the metal reflective film 4 is deposited directly on the layers 3R, 3G, and 3B, aluminum molecules as the material penetrate into the gaps of the phosphor particles, and light is lost. As a result, the intermediate layer is formed between the three-color phosphor layer (3R) (3G) (3B) and the metal reflective film 4, which is called a lacquer filming film (5). do.

The defect of the metal reflective film 4 which affects the brightness depends mainly on the method of forming the lacquer filming film 5, and directly affects the characteristics of the water pipe.

The lacquer film 5 has a problem in the composition, drying method, etc. of the lacquer solution, but also has the advantage that the baking process is omitted, to form a lacquer film film 5 to further planarize the lacquer film 5 A method of applying the prewet liquid 6 first has been proposed before.

That is, the prewetting liquid 6 is water-soluble, and forms an interface in an instant with the lacquer peeling liquid of the organic component to form a thin film on the three-color phosphor layer (3R) (3G) (3B), and thus formed lacquer film ( When the metal reflective film 4 is deposited in a state where the nonuniformity of the fluorescent film is reduced by 5), a flatter metal reflective film 4 can be realized.

Table 1 below shows the composition of the conventional prewet liquid 6, and Table 2 shows the composition of the lacquer peeling liquid.

TABLE 1

Drug name Chemical structural formula role PVA n = 2,400 Film formation Colloidal silica SiO ₂ Membrane assembly Triton Cationic surfactant Acetic acid CH ₃ COOH pH adjustment

TABLE 2

ingredient Furtherance role BMA 0.6 Film film formation Acryloide 0.5 Film film main ingredient Toluene 72.5 Main solvent M.I.B.K 2.29 Auxiliary solvent M.E.K 10.37 Auxiliary solvent Ethyl Acetate 13.11 Auxiliary solvent Iso-amyl acetate 5.0 Nitro Cellulose Solvent Dibuthyl Phthalate 0.5 Plasticizer Nitro cellulose 0.13 Film film formation

After depositing the metal reflecting film 4 as described above, baking is performed at a high temperature of about 450 ° C. In this process, the lacquer film 5 is decomposed and released to the outside, so that the metal reflecting film 4 and the tricolor phosphor are emitted. Constant voids may be formed between the layers 3R (3G) 3B.

However, in the general fluorescent film, the top surface of the three-color phosphor layer is roughly formed, and the height difference between the black matrix and the three-color phosphor layer is about 10 μm, whereas the thickness of the prewetting liquid and the lacquer film is only several tens of nm. There is a limit in obtaining the flatness required for the reflecting film. In addition, since the conventional prewet liquid has a (+) charge by the cationic surfactant and the black matrix has a (-) charge, the (+) charge of the prewet liquid The negative charges of the and black matrix reacted with each other, causing the liquid to precipitate, thus causing the flatness of the metal reflective film to be further roughened.

As such, when the metal reflective film is not formed flat, the reflection angle of the secondary electrons is small and diffuse reflection is large, and thus the luminance is lowered. When the luminance is lowered, the Ik current is increased to cause deterioration of the focus characteristic.

In order to solve this problem, the current situation is compensating the luminance by applying a back raster (external light irradiation).

By the way, such a white raster is effective in the luminance compensation surface, but rather a reduction in the color reproducibility surface, Figure 2 shows the color reproduction according to the presence or absence of the back raster through the CIE color coordinates, if there is a back raster ( Solid line) shows that the color purity is reduced and the color range is reduced by about 9%.

In the drawing, the hidden line is when there is no back raster.

In FIG. 2, x and y coordinates are based on a white fluorescent surface of 0.281 and 0.311, and the luminance of the cathode ray tube is 34fl and the luminance of the white raster is 0.4fl, and the color coordinates of red, green, and blue are shown in Table 3 below. .

TABLE 3

Classification location enemy rust blue Raster radish x 0.632 0.278 0.144 y 0.324 0.606 0.074 Raster Oil x 0.611 0.278 0.147 y 0.324 0.596 0.080

Accordingly, the present invention has been proposed in view of such a point, and an object thereof is to provide a method for forming a fluorescent film of a color cathode ray tube in which the flatness of a metal reflective film is improved by improving the method of forming a fluorescent film.

1 is a configuration diagram of a fluorescent film of a conventional color cathode ray tube,

2 is a CIE color coordinate of a tri-color phosphor with or without back raster,

3 is a configuration diagram of a fluorescent film of a color cathode ray tube according to the present invention.

*** Explanation of symbols for the main parts of the drawing ***

1 panel 2 black matrix

3R, 3G, 3B: three-color phosphor layer 4: metal reflective film

5: lacquer filming film 6: prewet liquid

7: white phosphor layer

In the method of forming a fluorescent film of a color cathode ray tube according to the present invention for achieving the above object, in the method of forming a fluorescent film of a color cathode ray tube sequentially forming a black matrix, a tricolor phosphor layer, and a metal reflective film on an inner surface of a panel: ( 1) forming a white phosphor layer including a white phosphor, ZnS: Ag + (Zn, Cd) S: Cu, on a top surface of the three-color phosphor layer: (2) the white phosphor layer in order to form the metal reflective film evenly Sequentially applying a prewet liquid and a lacquer peeling film to an upper surface of the (3) forming a metal reflective film by vacuum depositing aluminum on the upper surface of the lacquer film; And (4) thermally decomposing the prewet liquid and the lacquer film under high temperature to form a predetermined gap between the metal reflective film and the white phosphor layer.

Optionally, the white phosphor layer is a non-ionic reaction of ZnS: Ag + (Zn, Cd) S: Cu, which is a white phosphor, polyvinyl alcohol stilbarium salt with cationic properties, and the polyvinyl alcohol stilbarium salt. A white phosphor slurry containing an ionic surfactant is applied to the upper surface of the three-color phosphor layer and exposed to the white phosphor slurry for a predetermined time by ultraviolet rays such as mercury lamp, or ZnS: Ag + (Zn, Cd) which is a white phosphor. A dispersion liquid containing S: Cu, potassium silicate as a binder material, and barium nitrate as an electrolyte is applied to the upper surface of the three-color phosphor layer to be precipitated for a predetermined time.

Preferably, the average particle size of the white phosphor is less than 2/3 of the average particle size of the three-color phosphor constituting the three-color phosphor layer.

Preferably, the white phosphor layer is characterized in that formed on the average thickness of less than 3㎛.

In this way, since the white phosphor layer primarily reduces the height difference between the three-color phosphor layer and the black matrix, the metal reflective film can be formed more flatly. As a result, the electron beam toward the rear direction can be smoothly moved toward the front side of the panel. It is possible to re-reflect to improve the luminance characteristics, as well as to further improve the luminance characteristics by light emission of the white phosphor layer itself.

And, there may be a plurality of embodiments of the present invention, hereinafter will be described in detail with respect to the most preferred embodiment.

This preferred embodiment allows for a better understanding of the objects, features and advantages of the present invention.

Hereinafter, with reference to the accompanying drawings it will be described in detail a preferred embodiment of the fluorescent film forming method of the color cathode ray tube according to the present invention.

In addition, in drawing used for description, about the component same as FIG. 1, the same code | symbol is attached | subjected, and the overlapping description may be abbreviate | omitted.

The present invention is to more flatly form the metal reflecting film 4 that strikes the fluorescent film and reflects the electron beam reflected back to the front direction of the panel 1 to improve the luminance characteristics, as shown in FIG. After the three-color phosphor layer 3R (3G) (3B) is formed, the white phosphor layer 7 is first formed before the prewetting liquid 6 and the lacquer film 5 are formed. This is to reduce the height difference between the phosphor layers 3R (3G) (3B) and the black matrix (2).

The white phosphor layer 7 uses ZnS: Ag + (Zn, Cd) S: Cu, which is a white phosphor used in a conventional black and white cathode ray tube, and a slurry method, a precipitation method, or the like is used for the formation thereof.

First, the slurry method is a three-color phosphor layer comprising a white phosphor slurry including ZnS: Ag + (Zn, Cd) S: Cu, a white phosphor, a polyvinyl alcohol steel barzolium salt (PVA-SBQ) for forming a film, and a surfactant. (3R) (3G) (3B) is applied to the upper surface of the white phosphor slurry by applying ultraviolet light to form a white phosphor layer (7) by depositing, and the precipitation method is a white phosphor ZnS: Ag + (Zn, Cd ) Dispersion solution containing S: Cu, potassium silicate as binder material and barium nitrate as electrolyte is applied to the upper surface of tricolor phosphor layer (3R) (3G) (3B) and precipitated for a predetermined time. The phosphor layers 3R (3G) 3B and the white phosphor layer 7 are bonded to each other.

However, according to the slurry method in the above-described forming method, since the polyvinyl alcohol stilbarium salt contained in the white phosphor slurry has a cationic property, a white phosphor slurry is formed on the upper surface of the tricolor phosphor layer (3R) (3G) (3B). When applied, this portion is cationic, and the lacquer film 5 can be formed in a state in which the prewet liquid 6 does not precipitate due to the repulsive force of the prewet liquid 6 applied thereafter with the cationic surfactant. have. Therefore, it is obvious that the metal reflective film 4 can be formed more flatly.

At this time, the white phosphor layer 7 is less than the thickness of the three-color phosphor layer (3R) (3G) (3B) white characteristics in a range that does not inhibit the color purity of the three-color phosphor layer (3R) (3G) (3B) Should be minimized and the luminance effect raised.

Therefore, as the white phosphor, an average particle size of 2/3 or less of the average particle size of the tricolor phosphor should be used, and the white phosphor layer 7 is preferably formed to be 3 mu m or less.

In this way, the prewetting liquid 6 is obtained in a state where the height difference between the three-color phosphor layers 3R (3G) 3B and the black matrix 2 is primarily reduced according to the formation height of the white phosphor layer 7. ) And the lacquer filming film 5, the metal reflective film 4 can be formed more flatly.

However, since the white phosphor layer 7 may emit light by itself by hitting the electron beam, the metal reflective film 4 is flat as described above, so that the luminance and the white phosphor are increased by smoothly reflecting the secondary electron beam. An increase in luminance due to light emission of the layer 7 itself can be realized simultaneously.

On the other hand, the back raster used for the purpose of increasing the brightness of the prior art causes high power consumption and color reproducibility deterioration. In the fluorescent film according to the present invention, the luminance by the metal reflective film 4 and the white phosphor layer 7 increases. Since sufficient luminance characteristics can be obtained without using a back raster, there is an advantage of reducing power consumption and improving color reproducibility.

Hereinafter, the brightness characteristics and the contrast characteristics of the screen will be compared through the specific examples based on the above.

Example 1

A white phosphor, ZnS: Ag + (Zn, Cd) S: Cu, 203 g, polyvinyl alcohol stilbar barium salt 120 g, additional pure water 400 g, and surfactant 8 g were properly stirred to combine the phosphor slurry solution, which was then tricolor phosphor layer (3R). (3G) (3B) was applied at a speed of 20 rpm and developed at 200 rpm. The front surface of the white phosphor layer 7 was exposed for 15 seconds using ultraviolet light (365 nm) such as a mercury lamp of 220 mW / cm 2. It is formed.

Example 2

ZnS: Ag + (Zn, Cd) S: Cu 203g, white phosphor, 120g polyvinyl alcohol stilva barium salt, 400g additional pure water, nonionic surfactant Pluronic which does not ion react with polyvinyl alcohol stilva barium salt in surfactant BASF Corperation) 4g was properly stirred to combine the phosphor slurry solution, which was then applied to the upper surface of the three-color phosphor layer (3R) (3G) (3B) at a speed of 20 rpm and developed at 220 rpm. The white phosphor layer 7 was formed by exposing for 10 seconds using ultraviolet light (365 nm) such as a mercury lamp.

Example 3

ZnS: Ag + (Zn, Cd) S: Cu 120g, a white phosphor, 10g of Potassium Silicate, a binder material, and 100g of barium nitrate, an electrolyte, were used to make a dispersion solution. It is applied to the upper surface of (3B) and allowed to settle for about 1 minute, and the liquid is recovered to form a white phosphor layer 7.

Luminance and contrast characteristics of the fluorescent film according to each of these embodiments and the fluorescent film according to the prior art are shown in Tables 4 and 5 below.

[Table 4] Luminance (based on x, y color coordinate of white state)

Applied current Conventional fluorescent film Example 1 Example 2 Example 3 200 100.0% 110.0% 111.0% 111.2% 400 100.0% 112.0% 112.5% 112.9% 600 100.0% 113.0% 114.0% 113.8% 800 100.0% 115.0% 116.0% 116.7%

[Table 5] Contrast

Outside light intensity (Lux) Conventional fluorescent film Example 1 Example 2 Example 3 0 100.0% 100.0% 97.0% 99.2% 100 100.0% 99.0% 98.0% 98.9% 300 100.0% 98.0% 98.7% 98.8% 500 100.0% 98.2% 98.0% 98.8%

According to the present invention as shown in Table 4 and Table 5 it can be seen that the brightness characteristics and contrast characteristics are significantly improved compared to the conventional structure.

In addition, although specific embodiments of the present invention have been described and illustrated above, it is obvious that the present invention may be variously modified and implemented by those skilled in the art.

Such modified embodiments should not be individually understood from the technical spirit or the prospect of the present invention, and such modified embodiments should fall within the appended claims of the present invention.

As described above, in the present invention, after forming the three-color phosphor layer, the white phosphor layer is first formed on the upper surface thereof, and then the metal reflective film is formed to form the metal reflective film more flatly, thereby improving luminance characteristics. The luminance of the white phosphor can be further improved, and a white raster is not used, thereby reducing power consumption and improving color reproducibility.

Claims (5)

In the method of forming a fluorescent film of a color cathode ray tube in which a black matrix, a three-color phosphor layer, and a metal reflective film are sequentially formed on an inner surface of a panel: (1) forming a white phosphor layer including ZnS: Ag + (Zn, Cd) S: Cu, which is a white phosphor, on the upper surface of the three-color phosphor layer: (2) sequentially applying a prewet liquid and a lacquer film on the upper surface of the white phosphor layer to form the metal reflective film flat; (3) vacuum depositing aluminum on the upper surface of the lacquer film to form the metal reflective film; And And (4) forming a predetermined void between the metal reflective film and the white phosphor layer by thermally decomposing the prewet liquid and the lacquer film under high temperature. The method of claim 1, The white phosphor layer, A white phosphor slurry containing ZnS: Ag + (Zn, Cd) S: Cu, which is a white phosphor, a polyvinyl alcohol stilbar barium salt having cationic properties, and a predetermined surfactant is coated on the upper surface of the three-color phosphor layer, A method of forming a fluorescent film of a color cathode ray tube, characterized in that it is formed by exposing the white phosphor slurry for a predetermined time with ultraviolet light. The method of claim 1, The white phosphor layer, A dispersion containing white phosphor, ZnS: Ag + (Zn, Cd) S: Cu, binder silicate (Potasium Silicate), and electrolyte barium nitrate, was applied to the upper surface of the three-color phosphor layer to be precipitated for a predetermined time. The fluorescent film formation method of a color cathode ray tube characterized by the above-mentioned. The method of claim 1, The average particle size of the white phosphor is less than 2/3 of the average particle size of the three-color phosphor constituting the three-color phosphor layer, characterized in that the fluorescent film forming method of the color cathode ray tube. The method of claim 1, The white phosphor layer is formed with a thickness of less than 3㎛ on average, the fluorescent film forming method of the color cathode ray tube.