SU1109823A1 - Device for photographic exposing of mask screens of colour cathode-ray tubes - Google Patents

Abstract

1. DEVICE OF PHOTO-EXPOSURE OF MASSIC TABLE SCREENS OF COLOR ELECTRON-BEAM PIPES, containing a light source, a correction lens and a light filter located on its surface, consisting of metal discrete elements, a surface of a lens, a program and a program and a program and a program by the program; , characterized in that, in order to improve the quality of the screens produced, the thickness of the discrete elements is directly proportional to the transparency of the mask of the exposed electron beam t logging, and their number is within 400-1400 cm 2. The device according to claim 1, characterized in that the number of discrete elements per unit area is constant. (L from 00 to SA

Description

The invention relates to the electronics industry and can be used in the manufacture of screens of color cathode ray tubes (CELT).

There are known devices for the photoexposure of CELT mask screens containing a light source, a correction lens and a light filter in the form of a continuous metal coating deposited on a special transparent substrate or on the surface of a lens, experimentally 1.

The disadvantage of this filter is the complexity of its manufacture.

The closest technical solution is a device for photoexposure of CELT mask screens containing a light source, a correction lens and a light filter located on its surface consisting of metal discrete elements, the lens surface area occupied by light filter elements directly proportional to the illumination from the light source 2

The purpose of the invention is to improve the quality of the resulting screens.

This goal is achieved by the fact that in the photo-exposure device of CELT mask screens containing a light source, a correction lens and a light filter located on its surface consisting of metal discrete elements, the surface area of the lens is directly proportional to the illumination from the source of light, the thickness of discrete elements is directly proportional to the transparency of the mask of the exttonated cathode ray tube, and their number lies within 400-1400 cm

In addition, the number of discrete elements per unit area is constant.

FIG. 1 shows the proposed photoexposure device, a longitudinal section in FIG. 2 - part of the lens with a light filter top view; in fig. 3 - parts of a lens with a filter, cross section; in fig. 4 - curve of light transmission slit mask; in fig. 5 is a diagram of the thickness variation of discrete filter elements; in fig. 6 illustrates the distribution of illuminance from a light source over the surface of a screen without a light filter; FIG. 7 is a diagram of the variation of the area of the filter elements over the lens surface; in fig. 8 shows the light distribution curves over the screen surface using various light filters.

The photoexposure device of the CELT screens comprises a housing 1, a source 2 of light 2 successively placed in it, a correction lens 3 with a light filter 4 applied on it consisting of discrete elements 5. A screen-mask assembly consisting of a mask 6 and a screen 7 is mounted on the housing. The discrete light filter elements 5 vary, both in shape and in area, from the center to the edge of the filter (Fig. 2).

 This is the shape of the elements of a half-price filter by using its optical raster used in the printing industry to make it.

The thickness of the elements 5 light filter

5 (Fig. 3) 4 varies along the surface of the lens 3 from the center to the edge and depends on the light transmission of the mask, the change of which along the long axis of the mask is shown by curve 8 (Fig. 4). Curve 9 (Fig. 5) illustrates the change in the thickness of the light filter corresponding to

0 change the transparency of the mask. Curve 10 (FIG. B) shows the change in illumination produced by the light source without using a light filter. Curve 11 (Fig. 7) gives a change in the area of discrete elements from the center to the edge.

In addition, the distribution of illumination over the surface of the screen is shown using a conventional production filter - curve 12 (Fig. 8) and the proposed one - curve 13. It can be seen that the last one practically coincides with the calculated one - curve 14. Curve 13 is removed for a chromium optical filter, the number of discrete elements per 1 cm equals 900 pcs. the thickness decreases jot center to edges in limits of 250150 A, and the area of elements varies from

5 centers to edges within 0, 07 mm.

Due to the fact that the magnitude of the discrete

elements are outside the resolution of the human eye

and much smaller than the size of the mask opening,

0 the light filter as a whole is perceived by the eye as a tint with variable transparency and does not give moire when photoexposure. When the number of discrete elements of the filter per unit area is less than 400, moire appears, and with a number of more than 1400, the complexity of manufacturing the filter increases.

The use of the proposed photoexposure device for mask screens and CRT improves the distribution of illumination on the screen surface, which allows the manufacture of three-color screens with the required size of phosphor elements, which leads to an improvement in the quality of color images on television screens.

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Claims (2)

1. DEVICE FOR PHOTO EXPOSURE OF MASK SCREENS OF COLORED ELECTRON BEAM TUBES, containing a light source, a correction lens and a filter located on its surface, consisting of discrete metal elements, the lens surface area occupied by the filter elements being directly proportional to the illumination from the light source, is directly proportional to the illumination from the light source, is directly proportional to the illumination from the light source the fact that, in order to improve the quality of the resulting screens, the thickness of the discrete elements is directly proportional to the transparency of the mask of the exposed cathode ray tube, and their number lies in the range of 400-1400 cm 2. The device according to π. 1, characterized in that the number of discrete elements per unit area is constant.