Patent ID: 6099135
Filing Date: 2000-08-08
Classification: G02B

Abstract:
A surface light source device comprising:a light source;a light conductor which has a light incident face on at least one side end surface thereof which confronts said light source, and a light emitting face on one surface thereof which is substantially perpendicular to said light incident face; anda light angle varying sheet which is disposed at a side of said light emitting face of said light conductor,wherein at least one of said light emitting face and a back surface of said light conductor comprises a minute structure having an average slant angle of 0.5 to 7.5 degrees, said minute structure comprises a roughened surface which includes a plurality of fine convex members each having a substantially spherical surface, andwherein a ratio of a minute average radius of curvature to an average period of said convex members is set to 3 to 10, and a ratio of an average deviation of a distribution of the minute average radius of curvature to the minute average radius of curvature is set to 0.85 or less.