KR0130003B1 - Shadow-mask for cathode-ray tube - Google Patents

Abstract

A shadow mask for a cathode ray tube is fixed to a panel of the cathode ray tube along with the frame supporting and fixing a plurality of apertures through which a electron beam passes and which is formed on the plane that the electron beam passes through. The body of the shadow mask is formed with more than two metal layers each has different coefficient of thermal expansion. A portion having a high coefficient of thermal expansion is placed to the input side of the electron beam.

Description

Shadow Masks for Cathode Ray Tubes

1 is a perspective view of a general shadow mask.

2 is a partially enlarged cross-sectional view of a shadow mask of the present invention mounted to a panel.

Figure 3 is a partial cross-sectional view showing an exaggerated dominant phenomenon in the shadow mask according to the present invention.

* Explanation of symbols for drawings

10: beam passing through plane 11: beam passing through ball

12: low thermal expansion layer 13: high thermal expansion layer

20: panel

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shadow mask for a cathode ray tube, and more particularly, to a shadow mask for a cathode ray tube improved to minimize a landing error (ERROR) of a beam. Doming of the shadow mask in the shadow mask type cathode ray tube is unavoidable as long as a high speed electron beam is used as an energy source for image realization. Therefore, many manufacturers are attempting to research and develop in multiple directions to prevent deterioration of image quality caused by shadowing of shadow masks. However, the results so far are mostly focused on the development of low thermal expansion materials as shadow mask materials. According to such a material development, the material value of the shadow mask is increased, whereas the deterioration of the image quality due to the dominant phenomenon has not been greatly improved.

In other words, the dominant phenomenon causes deterioration of image quality such as color bleeding at the beginning of operation of cathode ray tube, and it is not only cumbersome to set the performance during the performance adjustment work at the end of the manufacturing process, From now on, the reliability of the product cannot be obtained. In order to solve such a problem, when using the low thermal expansion metal as described above, there is a disadvantage in terms of the manufacturing cost of the product. Accordingly, an object of the present invention is to provide a shadow mask for a cathode ray tube having a new structure that can effectively suppress the doming phenomenon caused by the electron beam to minimize the landing error of the electron beam during initial operation with the cathode ray to improve the reliability and quality of the product. Has its purpose. The shadow mask for the cathode ray tube of the present invention to achieve the above object is, a plurality of apertures through which the electron beam passes is formed in the beam passing plane, and is fixed to the panel with the cathode ray together with a frame for supporting and fixing, in particular its body It is composed of two or more metal layers having different thermal expansion coefficients, and is characterized in that a portion having a high thermal expansion coefficient is positioned on the incident side of the electron beam. Hereinafter, embodiments of the present invention will be described in detail. 2 shows a shadow mask of the present invention, which is made of a multi-ply metal material consisting of a low thermal expansion metal side 12 and a high thermal expansion metal layer 13. At this time, the high thermal expansion metal layer 13 is located on the incident side of the electron beam, and the low thermal expansion metal layer 12 is directed toward the panel. However, the single low thermal expansion metal ring 12 and the high thermal expansion metal layer 13 may be formed in a multi-layered metal plate each having a separate thermal expansion rate. However, on the average, the thermal expansion coefficient in the direction of incidence of the electron beam may be higher than that in the side facing the panel. Looking at the doming phenomenon in the shadow mask of the present invention having the above configuration as follows.

As shown in FIG. 3, when the high thermal expansion metal layer 13 in which the electron beam collides is thermally expanded at an intrinsic thermal expansion rate, the low thermal expansion metal layer 12 on the opposite side expands with a low thermal expansion rate. Therefore, when the high thermal expansion metal layer 13 is expanded, the low thermal expansion metal layer 12, which expands with a relatively low thermal expansion rate, serves to suppress thermal expansion of the high thermal expansion metal layer 13, and consequently toward the panel. Movement of the shadow mask, that is, doming, is suppressed. As a result, changes in the normal beam passing path before and after thermal deformation of the shadow mask are reduced. Therefore, deterioration of image quality is greatly reduced by the change of color tone in the initial operation of the cathode ray tube. In the present invention, Fes3C having a carbon content of 0.025 to 0.8% is suitable as a material of the low thermal expansion metal layer, and Fe pure iron having a carbon content of 0.004% or less is preferable, and the thickness of each layer is approximately the same. This is preferred. And, if each metal layer itself is a multi-ply metal layer in which different metals are laminated on each other, the above-described conditions may be met on average. As described above, the present invention uses a multi-layered material made of metals having different thermal expansion coefficients in order to effectively prevent the doming phenomenon in the shadow mask, and utilizes the mutual interference effect between the low thermal expansion metal and the high thermal expansion metal. As a result, the doming of the shadow mask by the electron beam is suppressed. As a result, it is possible to minimize the landing error of the electron beam during the initial operation of the cathode ray tube to improve the reliability and quality of the product. Moreover, since it is not necessary to use high-quality materials as in the prior art, it also contributes to the reduction of the manufacturing cost of the product. In addition, it is possible to minimize the landing error of the electron beam during the initial operation of the cathode ray tube to improve the reliability and quality of the product.

Claims (1)

In the shadow mask of the cathode ray tube fixed to the panel of the cathode ray tube, a plurality of apertures through which the electron beam passes is formed in the beam passing plane, and are fixed to the panel of the cathode ray tube with a frame supporting and fixing the body. However, the shadow mask for cathode ray tube, characterized in that the portion having a high thermal expansion coefficient is configured to be located on the incident side of the electron beam.

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