Patent ID: 8842364

Claim:
An optical device that has an antireflection function, the optical device comprising: a base; and a plurality of structural bodies, which are formed by convex portions or concave portions, arranged on a surface of the base with a fine pitch that is equal to or smaller than a wavelength of visible light, wherein the plurality of structural bodies are arranged so as to form tracks of a plurality of rows on the surface of the base and form a quasi-hexagonal lattice pattern, a tetragonal lattice pattern, or a quasi-tetragonal lattice pattern, and wherein a packing ratio of the structural bodies to the surface of the base is equal to or higher than 65%, the packing ratio being defined by the following Equation (3): packing ratio=( S (hex)/ S (unit))×100 Equation (3) where S(unit) is an area of a unit lattice defined by P1×2Tp, where P1 is an arrangement pitch of the plurality of structural bodies within a same track and Tp is a track pitch, and S(hex) is an area of bottom surfaces of the structural bodies that exist within the unit lattice.