KR20050005269A - CRT's coating layer - Google Patents

Abstract

PURPOSE: A coating film is provided to achieve improved contrast by using a black pigment and a pigment having an absorbing function at a specific wavelength. CONSTITUTION: A coating film is deposited on an outer surface of a panel of a cathode ray tube. The coating film is formed by coating a liquid containing silica, a conductive metal material, a black pigment for transmissivity adjustment, and a selected wavelength absorbing pigment for selectively absorbing a wavelength of 550 to 600nm.

Description

Cathode ray tube coating film {CRT's coating layer}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating film of a cathode ray tube, and more particularly, to a coating film that can improve contrast over an entire wavelength region while blocking static electricity emitted to a panel surface of a cathode ray tube.

In order to look at the conventional cathode ray tube coating film, it will be described with reference to FIGS. 1 to 4 as follows. 1 is a side cross-sectional view of a general color cathode ray tube, with reference to this will be described the structure and operation of a general color cathode ray tube.

The cathode ray tube (CRT) is used in all display devices that implement an image in a form that can be seen by a human eye as well as a television. An electric signal incorporating image information is generated by an electron beam. It converts and displays optical images such as figures and characters.

These cathode ray tubes are being replaced by flat surface or flat panel cathode ray tubes with flatness of the panel to compensate for image differences between the front and left and right sides, including distortion of the image, which is a disadvantage of the conventional convex CRT. .

The flat panel type cathode ray tube basically includes a panel, a shadow mask, a funnel, an electron gun, a deflection yoke, and the panel 1 includes: As a part of the front surface of the CRT, that is, the screen, the vacuum container forms a part of the vacuum vessel and image information is converted into final visual information.

Inside the panel 1, a phosphor layer 8 in which a three-primary phosphor pixel composed of each of three primary colors of light, R (Red), G (Green), and B (Blue), is deposited in a dot or stripe form. A shadow mask 4 is arranged adjacent to the phosphor 8 and serving as a color selection electrode.

The shadow mask 4 allows the three-color electron beam emitted from the electron gun to reach the fluorescent surface inside the panel 1 accurately, and the funnel 2 is coated with a conductive film therein, and the shadow mask 4 And the anode voltage to the final electrode of the electron gun 7 to be inserted.

The electron gun 7 is a device that emits an electron beam according to an electric signal for displaying image information. The electron gun 7 is inserted and mounted in the funnel 2, and the deflection yoke 6 vertically moves the electron beam emitted from the electron gun 7. By scanning from side to side, the secondary image is reproduced.

That is, the electron beam passes through the shadow mask 4 to reach the phosphor film 8, and the phosphor film 8 emits light by the energy of the electron beam to reproduce an image.

The cathode ray tube having such a structure has a large radius of curvature so that the outer surface is close to the plane for the planarization of the panel 1, and the inner surface of the phosphor layer 8 is not damaged when the screen is viewed from the outside. It has a curvature radius that is not enough, and it consists of a relatively small radius of curvature compared to the outer curvature.

As the cathode ray tube is planarized as described above, the thickness of the corner side becomes thicker than the thickness of the center side, thereby increasing the brightness difference between the center side and the corner side. That is, since the thickness of the corner side becomes thicker, there is a problem that the image displayed through the corner side panel is darker than the center side image. In order to solve such a problem, a panel is constructed by replacing tin glass, which has been conventionally used, with clear glass having a high light transmittance.

The clear glass has a high transmittance of about 78%, so that the brightness (contrast) of the glass is lowered by bright ambient light on its own, thereby degrading the overall image quality. In order to solve this problem, conventionally, the black pigment is added to coat the panel to improve contrast.

The light produced by the phosphor is light representing the image information to be displayed by the cathode ray tube and has a peak in a specific wavelength region, and is displayed in various colors by a combination thereof, and has a continuous wavelength in the visible region. Since the reflected light of the external light source has light of a wavelength other than the light emitted by the phosphor, this serves as a factor that inhibits the contrast of the image through the panel.

Thus, another conventional coating method has been to use pigments having an absorption function at specific wavelengths. 2 is a graph showing the color intensity of the light emitted from a specific wavelength band, it will be described with reference to the conventional coating method as follows.

In general, the wavelength of blue light in the 450nm band, green in the 540nm band and red in the 630nm band emits light with relatively high intensity. In particular, the red phosphor emits a large number of side bands in the vicinity of 580nm. It has a factor which reduces the contrast of a cathode ray tube.

In addition, the light of the 580nm wavelength is not only a high ratio of the external light, but also has a high luminous efficiency of the eye, and when the external light is reflected on the panel, there is a disadvantage that the eyes of the viewer watching from the front.

In this coating method, a black coating applied with a black pigment or a selective wavelength absorption coating for selectively absorbing a specific wavelength is applied, and graphs showing light transmittances of the respective coating methods are illustrated in FIGS. 3 and 4.

In the case of the black coating to which the conventional black pigment is applied, the transmittance is lowered over the entire wavelength range, but the contrast may be improved, but the color purity may be deteriorated. In addition, the selective wavelength absorption coating has a disadvantage in that it is difficult to improve contrast because the color purity is good but the transmittance of the entire range cannot be reduced.

If the pigment is added excessively to reduce the transmittance, the coating color becomes dark purple, resulting in a deterioration of appearance and deterioration of the display state of the image, and an increase in resistance of the outer surface of the panel. .

The present invention has been made to solve the above-mentioned problems of the prior art, the object of which is to provide a cathode ray tube in which an antistatic colored coating film is formed in order to block the static electricity emitted to the surface of the panel, and to improve contrast, By adding a black pigment and a pigment having an absorption function at a specific wavelength, it is possible to improve the contrast over the entire wavelength and to provide a coating film of the cathode ray tube that can optimize the display state of the image by absorbing the wavelength overlapping with the external light in itself. have.

1 is a side cross-sectional view of a typical color cathode ray tube,

2 is a graph showing the color intensity of light emitted from a specific wavelength band,

3 is a graph showing the transmittance of the coating film by the conventional black coating method,

Figure 4 is a graph showing the transmittance of the coating film by a conventional selective wavelength absorption coating method,

5 is a graph showing the transmittance of the coating film according to the present invention,

6 is a graph showing the total transmittance of the CRT formed coating film according to the present invention,

7 is a graph comparing color intensity for each wavelength of the coating film according to the present invention.

<Explanation of symbols on main parts of the drawings>

G1: color intensity graph according to the present invention,

G2: color intensity graph according to the present invention,

According to the characteristics of the coating film of the cathode ray tube according to the present invention for solving the above problems, in the coating film applied to the outer surface of the cathode ray tube, the coating film is silica, conductive metal material, black pigment for controlling the transmittance and 550nm to A coating liquid containing a selective wavelength absorbing pigment for selectively absorbing a wavelength band of 600 nm is formed on the outer surface of the panel.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Figure 5 is a graph showing the transmittance of the coating film according to the present invention, Figure 6 is a graph showing the total transmittance of the CRT formed coating film of the present invention, Figure 7 shows the relative strength for each wavelength when using the coating liquid of the present invention It is a graph compared with the conventional invention.

In the case of a large CRT such as a TV, it is common to have a single layer of coating film formed on the panel due to difficulties in the production process, and in order to prevent the increase of manufacturing cost and the complexity of the production process generated when the multilayer coating film is formed. The coating liquid of black pigment, selective wavelength absorbing pigment, the conductive metal material and the silica binder is characterized in that the mixed at the same time, such a mixed coating liquid to form a single coating film on the panel.

To this end, the coating solution according to the present invention comprises a black pigment for reducing the light transmittance of the entire wavelength range.

The black pigment is a pigment for controlling the light transmittance of the entire wavelength band, carbon black, titanium black and the like can be used, and as shown in Figure 4 transmittance relatively uniformly in the entire wavelength band 50% ~ 60% level Since the function of lowering, the coating liquid of the present invention to adjust the blending ratio of such a black pigment so that the average transmittance of the coating film is 55% to 70%. For this purpose, black pigment is added with a weight ratio of 35 to 45 wt% based on the total pigment.

In addition, the coating liquid of the present invention comprises a selective wavelength absorbing pigment that selectively absorbs a specific wavelength band.

Here, since the surface of the cathode ray tube is smooth and external light is specularly reflected, it may be tiring for the viewer to watch from the front, and as described in the description of the related art (see FIG. 2), the side band of the 580 nm wavelength band is shown. Since light has a high constituent ratio of external light, the coating film of the panel absorbs the wavelength of 550 ~ 600nm using the selective wavelength absorbing pigment to selectively remove it. This makes it possible to diffuse the external light and reduce the reflected light.

In addition, as a selective absorbing dye having a maximum absorption in the wavelength range of 550 ~ 600nm, a pigment having a violet color of Thioindigo-based, Dioxazine-based, Anthraquinone-based can be used, these pigments are generally excellent in light resistance, chemical resistance, water resistance, etc. Has an advantage.

In this case, the particle size of the colored pigment such as black pigment or selective wavelength absorption pigment is preferably smaller than the particle diameter of the conductive metal material, and the content of the colored pigment is 0.1 to 1.0% by weight (wt%) based on the total coating liquid. It is suitable to do.

Here, the transmittance for each combination ratio when the selective wavelength absorption pigment and the black pigment are combined at different ratios will be described with reference to Table 1 and FIG. 5.

A (Combination Cost 1) B (Combination Cost 2) C (Combination Cost 3) D (Combination Cost 4) E (Combination Cost 5) Selective wavelength absorption pigment 100wt% 80wt% 70wt% 60wt% 50 wt% Black Pigment 0wt% 20wt% 30wt% 40wt% 50 wt% Transmittance 77.3% 70.5% 67.2% 60.3% 55.7% Contrast 12.7% 14.6% 16.7% 19.8% 22.5%

As shown in Table 1, the combination ratio of [selective wavelength absorption pigment: black pigment] was divided into A, B, C, D, and E cases, and the results of the test group's transmittance and contrast were examined. It was possible to ensure proper transmittance while maintaining high contrast.

Accordingly, it can be seen that the selective wavelength absorbing pigment has a weight range of 55 to 65 wt%, and the black pigment has a weight range of 35 to 45 wt% and is preferably mixed.

In addition, since the panel of the cathode ray tube is formed of a glass material which is a non-conductor, electrostatic charges accumulate at the time of power on / off of the CRT and attract dust on the panel surface, and thus, a conductive metal material is applied to the coating liquid of the present invention. Includes. In addition, a silica solution containing a conductive metal oxide may be added.

Here, the sheet resistance of the coating film may be adjusted to the thickness of the coating liquid applied on the panel to be 10 ⁸ Ω to 10 ¹¹ Ω.

In addition, the coating liquid specifies that pigments such as blue or purple may be added by the producer to adjust the coating color.

The overall transmittance of the CRT to which the coating liquid prepared in this way is applied will be described with reference to FIG. 6. In this case, the graph of FIG. 6 may be compared with the transmittance for each wavelength by the method using only the black pigment shown in FIG. 3 and the transmittance for each wavelength by the method using only the selective wavelength absorption pigment shown in FIG. 4.

That is, the overall transmittance is uniformly distributed for each wavelength within the range of 50 to 70%, and absorbs the wavelength of 550 ~ 600nm sufficiently to lower the transmittance can solve the conventional problems.

Looking at the side band of 550 ~ 600nm with reference to Figure 7, it can be seen that the relative strength of the side band is lowered by the coating liquid of the present invention (G2) compared to the conventional coating method (G1). Thereby, the problem (contrast reduction, specular reflection) by a side band can be overcome.

As described above, the coating liquid of the cathode ray tube and the coating layer formed of the coating liquid according to the present invention have been described with reference to the illustrated drawings, but the present invention is not limited by the embodiments and drawings disclosed herein, This can be applied within the scope of protection of the technical idea.

The coating film of the cathode ray tube of the present invention configured as described above can reduce the amount of black pigments that have been conventionally used by simultaneously using black pigments and selective wavelength absorbing pigments, which is expected to reduce production costs, while maintaining the same contrast level and brightness. Not only can the reduction be alleviated, but the pigment component that selectively absorbs a specific wavelength can absorb the side band around 580nm to increase the color purity, thereby improving the reliability of the product.

Claims (5)

In the coating film applied to the outer surface of the panel of the cathode ray tube, The coating film is a coating film of a cathode ray tube, characterized in that the coating liquid containing silica, a conductive metal material, a black pigment for controlling the transmittance and a selective wavelength absorbing pigment selectively absorbing the wavelength band of 550nm to 600nm is formed on the outer surface of the panel. The method of claim 1, The coating film of the cathode ray tube, characterized in that the mixing ratio of the black pigment is adjusted so that the average transmittance of the coating film is 55% to 70%. The method of claim 1, The sheet resistance of the coating film is a coating film of the cathode ray tube, characterized in that the thickness of the coating liquid is adjusted to be 10 ⁸ Ω to 10 ¹¹ Ω. The method of claim 1, The selective wavelength absorbing pigment has a weight range of 55 to 65wt%, the black pigment has a weight range of 35 to 45wt%, the coating film of the cathode ray tube, characterized in that mixed. The method of claim 1, The coating film is a coating film of a cathode ray tube, characterized in that a blue or purple pigment is added to adjust the coating color.