Antireflection microstructures, optical filters, optics, and methods for manufacturing antireflection microstructures

摘要

PROBLEM TO BE SOLVED: To provide an antireflection fine structure that offers a high reflection reducing effect and improved rigidity, and to provide an optical filter, light volume adjusting unit, and optical device.SOLUTION: An antireflection fine structure comprises a transparent substrate and a fine structure provided on top of the transparent substrate, the fine structure having a plurality of protrusions provided at a pitch no greater than visible-ray wavelengths in a surface direction of the transparent substrate. The protrusions comprise a plurality of first protrusions spaced apart by a predetermined distance and a plurality of second protrusions, each being provided between a pair of adjacent first protrusions and having a height, from a surface of the transparent substrate to an apex thereof, that is less than that of the first protrusions. Area of a bottom of the first protrusion facing the transparent substrate is greater than area of a bottom of the second protrusion facing the transparent substrate.SELECTED DRAWING: Figure 1