MOLD FOR LIGHT GUIDE PLATE INJECTION MOLDING AND LIGHT GUIDE PLATE MANUFACTURING METHOD USING SAME

摘要

A mold for injection-molding a light guide plate in which pin gates and/or film gates for injecting a molten resin molding material into a cavity portion are provided to a portion of the mold corresponding to a side surface of the light guide plate to be produced. Another mold for injection-molding a light guide plate in which a fluidity balance chamber supplied with a molten resin molding material and composed of an ear-shaped portion is interposed between each gate and a sprue or a runner. Further another mold for injection-molding a light guide plate in which the areas of the gates are determined so that the temperatures of the molten resin passing through gates and introduced into a cavity may be higher by 5°C or more than the temperatures of the molten resin introduced into fluidity balance chambers because of the shear heating in passing through the gate. A method for manufacturing a light guide plate by using them. An injection-molded article which is free of weld line, sink mark, flow mark, and warp, has a favorable quality, is facilitated in cutting gates, and requires no finishing process can be produced.