Patent ID: 8164833

Claim:
A solar-powered watch, comprising: an optical window member, including— a transparent synthetic resin plate having a top surface with a pattern of a plurality of concentric and contacting protrusions/recesses that cause light diffusion, and a bottom surface opposite the top surface; and an optical thin film having a top surface and a bottom surface, the bottom surface being positioned at the top surface of the transparent synthetic resin plate, each of the top and bottom surfaces of the optical thin film having a protruding/recessed pattern corresponding to the pattern on the top surface of the plate, wherein the optical thin film is a top layer of the optical window member, and wherein each of the protruding/recessed patterns is regularly arranged at a predetermined same pitch; and a solar battery positioned near the bottom surface of the plate, wherein light irradiated in a direction perpendicular to the top surface of the optical thin film enters the optical thin film through the pattern on the top surface of the optical thin film, some of the entering light is reflected by the pattern on the top surface of the plate out of the pattern on the top surface of the optical thin film, a remainder of the light passes through the pattern on the top surface of the plate, some of which charges the solar battery and some of which is reflected by the battery and exits through the patterns and out the top surface of the optical thin film, and wherein the light diffusion substantially prevents seeing the battery through the optical window member.