Antireflection Structure and Optical Device Including the Same

摘要

A diffusing plate has a surface including a plurality of fine concave/convex portions regularly arranged within a cycle equal to or smaller than a predetermined wavelength. The surface has a larger surface roughness than the predetermined wavelength. An average value for an angle between a normal vector of the tangent plane of a roughness shape of the surface and a normal vector of a reference plane of the surface is 5 degrees or more.