Optical element and method for manufacturing the same, and method for manufacturing master

PROBLEM TO BE SOLVED: To provide an optical element having excellent antireflection characteristics.SOLUTION: An optical element having an antireflection function is provided, which includes a substrate and a structure comprising a projection or a recess disposed in a great number at a fine pitch equal to or smaller than a wavelength of visible light on a surface of the substrate. Each structure is arranged to form a plurality of rows of tracks on the substrate surface and to form a quasi-hexagonal lattice pattern, a tetragonal lattice pattern or a quasi-tetragonal lattice pattern. A fill factor of the structure with respect to the substrate surface is 65% or more.SELECTED DRAWING: Figure 1