Method of making light guide member.

摘要

A front end portion (14b) of a flat plate-like transparent thermoplastic material is grasped as bent so that the middle section thereof is convex. The thermoplastic material is heated and softened, and the rear end portion (14c) of the thermoplastic material is rounded cylindrically in the same direction as the bending direction ofthefrontend portion. The thermoplastic material is then allowed to cool gradually, so that the front end portion has a flat plate-like shape (H) after the gradual cooling. The cylindrical rear end portion is cut and the cut face is planished.