METHOD OF INJECTION MOLDING PLASTIC LENS

摘要

A cavity 22 in an injection molding assembly includes a lower mold insert 21 for shaping a lens convex surface and an upper mold insert 20 for shaping a lens concave surface. When the heated injection molding assembly is cooled and a lens is ejected after a molten resin is pressurized by the upper mold insert 20, the temperature of the lower mold insert 21 is lowered below the temperature of the upper mold insert 20, which prevents the molded lens from bending at a central portion and enable high transfer precision of insert shapes.