US Patent 7267912 Exposure mask and pattern exposure method

An exposure mask which is capable of reducing non-uniformity in a display such as a liquid crystal display device. A first mask pattern having pattern-forming portions and shield portions mosaically arranged therein is formed in one end portion of an exposure mask, and a second mask pattern having pattern-forming portions and shield portions arranged in a manner complementary to the first mask pattern is formed at the other end portion of the exposure mask. The exposure mask is formed such that areas between vertically or laterally adjacent ones of the shield portions, in mosaic areas where pattern-forming portions and the shield portions are mosaically arranged, are also shielded.