Surface treatment process

摘要

On an optical device, a metal mask is formed in the shape of a dot array, and then reactive ion etching is performed. The etching is continued while the diameter of the metal mask gradually becomes smaller until the area of the metal reduces to a predetermined area. This produces on the optical device a conical shape with a high aspect ratio, realizing an anti-reflection structure that exerts an anti-reflection effect on light spreading in a range of wavelengths wider than ever and that depends less on the angle of incidence