Patent ID: 8023190

Claim:
An antireflection structure for suppressing reflection of light having a wavelength equal to or larger than a predetermined wavelength, the antireflection structure comprising: a surface having a roughness shape with a larger surface roughness than the predetermined wavelength; and a plurality of fine concave/convex portions regularly arranged on the surface within a cycle equal to or smaller than the predetermined wavelength, wherein: the surface is configured so that a percentage of an area per unit area of part in which angles between normal vectors of tangent planes of the roughness shape of the surface and normal vectors of a reference plane of the surface which is obtained by cutting off the fine concave/convex portions and the roughness shape is 10 degrees or less is less than 90%, each of the plurality of fine concave/convex portions has a height equal to or larger than 0.4 times as large as a wavelength of light of which reflection is suppressed, and a surface roughness of the surface in terms of a maximum height roughness Rz defined by ISO4287:1997 is larger than the predetermined wavelength.