Tension mask for color crt, method for manufacturing the tension mask, and exposure mask used in the manufacture of the tension mask

Abstract

A tension mask for a color cathode-ray tube, a method for manufacturing the tension mask, and an exposure mask for use in the manufacture of the tension mask are provided. The tension mask is manufactured by depositing photosensitive layers over the top and bottom surfaces of a steel foil. An upper exposure mask with a pattern including a series of parallel upper light transmission portions arranged in lines is aligned over the top surface of the steel foil, and a lower exposure mask with a pattern is aligned over the bottom surface of the steel foil. Here, the pattern of the lower exposure mask includes a series of parallel lower light transmission portions arranged in lines, a plurality of first light shielding portions intersecting adjacent lower light transmission portions among the series of the parallel lower light transmission portions, and a plurality of second light shielding portions partially extending between the edges of the adjacent lower light transmission portions. Following this, the photosensitive layers uncovered with the lower and upper exposure masks are exposed using an exposure light source, and then the upper and lower exposure masks are removed from the steel foil and developing the photosensitive layers remaining on the steel foil. Lastly, the steel foil which has undergone the developing process is etched, so that the tension mask is completed.