Optical element and method for producing the same

An optical element having an anti-reflection function, comprising:

• a base having a first main surface and a second main surface;
• a plurality of structures composed of projections or recesses and arranged on the first main surface at a fine pitch equal to or less than the wavelength of visible light for which the amount of reflection is to be reduced;
• and
• a light-absorbing layer that absorbs the light and that is disposed on the second main surface, the light-absorbing layer being bonded to the base with an adhesive layer, wherein the refractive index of the base is substantially the same as the reflective index of the adhesive layer such that reflection at an interface between the base and the adhesive layer can be suppressed,
• wherein the structures are arranged so as to form a plurality of rows of tracks on the first main surface of the base and form a hexagonal lattice pattern, a quasi-hexagonal lattice pattern, a tetragonal lattice pattern, or a quasi-tetragonal lattice pattern, and
• the structures each have an elliptical cone shape or a truncated elliptical cone shape, the major axis direction of which is a direction in which the tracks extend.