| 摘要 |
<p>PURPOSE:To provide a diffusion plate which secures a bright visual field having no feeling of roughness by controlling the diffusion characteristics and is free from multi-line defocusing and a color irregularity by superposing plural basic patterns, where two-dimensional periodic fine structures are arranged, in out-of- phase relation. CONSTITUTION:A mask which has a two-dimensional period fine patterns is irradiated with ultraviolet rays from behind to project the fine patterns on the top surface of a photoresist film on a substrate 1, thus exposing the surface. Then the mask is rotated by 5 deg. in the same plane and the fine patterns are projected for exposure. The uneven relief which is thus obtained decrease in height in the order of parts X where dots constituting the fine patterns 6 are projected one over the other, parts Y where the dots are independently projected, and parts Z other than the dots. This substrate 1 is molded as the matrix for the diffusion plate, an electrocasting metallic mold is manufactured on the basis of this substrate 1, and the uneven relief is transferred to optical resin by injection molding to obtain the diffusion plate.</p> |
