Resin-molded prism and mold for the same

Abstract

A flow mark or residual stress occurring in the vicinity of a gate adversely affects the optical characteristics of a resin prism which is to be formed by injection molding. Thus, the molding conditions for the resin prism are strict, and accordingly the resin prism has poor moldability. In view of this, according to this invention, the resin prism includes two or more optical surfaces (11-13) that are not parallel to each other, a pair of side end faces (14, 15) substantially perpendicular to the optical surfaces (11-13), at least one reference block (17) projecting from either one of the pair of side end faces (14, 15) and having a circumferential end face (16) extending in a projecting direction of the reference block, a positioning portion (19, 20) formed on the circumferential end face (16) of the reference block (17), and a curved surface (18) for smoothly connecting the circumferential end face (16) of the reference block (17) and corresponding one of the pair of side end faces (14, 15), wherein the circumferential end face (16) and the corresponding one of the side end faces (14, 15) form an angle of 90° or more.

Dependencies are inferred from the claim text.