KR100445026B1 - Cathode ray tube screen film using green filter film capable of improving luminance of screen film and preventing degradation of contrast even in case where glass panel with high transmissivity is employed - Google Patents

Abstract

PURPOSE: A cathode ray tube screen film is provided to achieve improved luminance of the screen film and prevent degradation of contrast even when a glass panel having a high transmissivity is used. CONSTITUTION: A cathode ray tube screen film comprises a glass panel(210); a black matrix formed on the glass panel; a phosphor film formed on the black matrix; and a green filter film(230) formed between the glass panel and the black matrix or between the black matrix and the phosphor film. The green filter film is made of a composition having a green pigment.

Description

Cathode ray tube screen membrane with green filter membrane

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube, and more particularly, to a cathode ray tube screen membrane capable of preventing a decrease in contrast while improving brightness by using a glass panel having high transmittance.

In general, green, blue and red light emitting phosphor patterns are regularly arranged in the form of dots or stripes in the color cathode ray tube screen film, and a black matrix is formed between the phosphor patterns to improve contrast and color purity of the screen film. . When electrons are irradiated from the electron gun on such a screen film, the phosphor emits light and the required image is realized.

This conventional colored cathode ray tube screen membrane is shown in FIG.

That is, the black matrix pattern 120 is formed on the glass panel 110, and the fluorescent film to which the red, green, and blue phosphors 140, 150, and 160 were respectively applied is formed between the black matrix patterns.

The factors for determining the brightness and contrast of the cathode ray tube screen film having such a structure are very diverse, and they also show a correlation with each other.

Among various factors that determine the brightness and contrast, one of the most influential ones is the transmittance of the glass panel.

Generally, glass panels that can be used for cathode ray tubes are classified according to transmittance, such as dark-tint glass panels having a transmittance of 40-50%, semi-tint glass panels having 50-60%, and It can be roughly classified into a clear-tint glass panel which is 80-90%, and the brightness and contrast characteristics of the cathode ray tube screen film vary depending on the type of glass panel employed.

In more detail, when the dark tint glass panel is used, the external light is absorbed by the glass panel, and the contrast is improved. However, since the light excited by the phosphor is also absorbed by the glass, the luminance is lowered. On the contrary, in the case of using a clear glass panel, since the light excited by the phosphor mostly passes through the glass, the brightness is high, but the contrast is lowered because external light is not absorbed by the panel.

That is, the brightness and contrast characteristics are inversely proportional to the transmittance of the glass panel used.

Therefore, when using a glass panel with high transmittance in order to improve the brightness, there is a problem in that a significant reduction in contrast is to be taken.

In order to overcome these problems, various methods have been studied in which a glass panel having high transmittance is used to improve brightness while not lowering contrast.

One of them is to process color on the outer surface of the semi-tint panel. However, this method has the disadvantage that the process is not only complicated and uneconomical, but also high in defect rate.

Another method is to attach an excessive amount of pigment to a phosphor. The phosphor itself is white in color, so it completely reflects light. As a method of reducing the reflectance of such external light, a red pigment, a green pigment and a blue phosphor are attached to the phosphor and used. However, as the pigment deposition amount increases, the luminance decreases and the contrast improves. Applying this to excessive use of the pigment while using the clear panel, the brightness can be improved while the contrast can be prevented.

However, this method not only lowers the luminous efficiency of the phosphor itself due to the excessive adhesion of the pigment, but also has the disadvantage that the present pigment attachment technology cannot achieve the brightness improvement effect as expected.

The technical problem to be achieved by the present invention is to provide a cathode ray tube screen membrane that can prevent the degradation of the contrast while increasing the brightness of the screen membrane by using a glass panel with high transmittance.

Technical problem of the present invention, a glass panel; A black matrix formed on the glass panel; And a fluorescent film formed on the black matrix, wherein the green film is formed between the glass panel and the black matrix or between the black matrix and the fluorescent film. Can be done.

The green filter film is formed from a composition for forming a filter film containing a green pigment, and the green pigment preferably has a color coordinate having a wavelength range of 495-560 nm and a particle size of 20-500 nm.

When the wavelength range of the green pigment is out of the range, the combination of each phosphor and filter of red, green, and blue is not preferable because the coordinates of each color are out of tolerance. In addition, if the particle size is less than 20nm, the transmittance is too high to have the characteristics of the pigment, while if the particle size exceeds 500nm, the light transmittance is too low to block fluorescence, thereby decreasing the luminance.

On the other hand, it is preferable that the glass panel used is semi tint or clear.

Hereinafter, with reference to the drawings will be described in detail the principle of the present invention and a method for producing a cathode ray tube screen film.

2 and 3 are cross-sectional views showing a screen film of a cathode ray tube according to the present invention.

In FIG. 2, the composition for forming a filter film including a green pigment is coated on the glass panel 210, and then exposed to a full surface to form a green filter film 230. Subsequently, a black matrix pattern 220 is formed on the green filter film, and then red, green, and blue phosphors 240, 250, and 260 are coated on the unformed black matrix pattern 220 to form a fluorescent film.

In contrast, in FIG. 3 as another aspect of the present invention, the black matrix pattern 320 is formed on the glass panel 310. Subsequently, a composition for forming a filter film including a green pigment is coated on the black matrix pattern 320, and then subjected to full exposure to form a green filter film 230, and then red, green, and blue on the filter film. Phosphors 240, 250 and 260 are applied to form a phosphor film.

Here, as a method for producing the black matrix and the fluorescent film, a conventional method is used.

That is, the principle of the present invention is that the black filter film compensates for the lowering of contrast that may be caused by using a glass panel having a higher transmittance than the glass panel used in general. Therefore, it is to obtain a screen film having good brightness and contrast.

Hereinafter, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited to this.

Example

After forming a black matrix pattern on a glass panel having a transmittance of 65%, a green filter film-forming composition having the following composition was applied on the black matrix pattern, and then subjected to full exposure to form a green filter film:

100 g of water

Green pigment substance 10g

5g polyvinyl alcohol

1 g of surfactant (PES)

Photosensitizer (SDC) 0.5g

Dispersant (sodium citrate) 0.1 g

Subsequently, a fluorescent film was formed on the green filter film using Y ₂ O ₂ S: Eu as a red phosphor, ZnS: Ag, Cl as a blue phosphor, and ZnS: Cu, Au, Al as a green phosphor.

The brightness and contrast of the screen film produced as described above were measured, and the contrast was expressed as the brightness at the screen on under the external light / the brightness at the screen off. The results are shown in Table 1 below.

Comparative example

A screen film was prepared in the same manner as in Example 1 except that a glass panel having a transmittance of 53% was used. The brightness and contrast thereof were measured, and the results are shown in Table 1 below.

Luminance Contrast Example 38fL 30: 1 Comparative example 34fL 30: 1

From the results of Table 1, in the case of the screen membrane employing the green filter membrane, the same level of contrast can be achieved while improving the luminance by 10% or more by using a glass panel having a high transmittance as compared with the comparative example of the conventional screen membrane. It can be seen that can be maintained.

The screen film of the cathode ray tube according to the present invention has the advantage that the contrast can be prevented while maintaining the effect of greatly improving the luminance even when a glass panel having a high transmittance is used.

1 is a cross-sectional view of a conventional cathode ray tube screen membrane.

2 is a cross-sectional view of a cathode ray tube screen membrane according to an embodiment of the present invention.

3 is a cross-sectional view of a cathode ray tube screen membrane according to another embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

110, 210, 310 ... glass panels

120, 220, 320 ... Black Matrix Pattern

140, 240, 340 ... red phosphor

150, 250, 350 ... green phosphor

160, 260, 360 ... blue phosphor

230, 330 ... green filter membrane

Claims (4)

Glass panels; A black matrix formed on the glass panel; And a fluorescent film formed on the black matrix. And a green filter film is formed between the glass panel and the black matrix or between the black matrix and the fluorescent film. The cathode ray tube screen film according to claim 1, wherein the green filter film is formed from a composition for forming a green filter film containing a green pigment. 3. The cathode ray tube screen of claim 2, wherein the green pigment has a color coordinate in the range of 495-560 nm. The cathode ray tube screen membrane of claim 2, wherein the green pigment has a particle diameter of 20-500 nm.

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