METHOD FOR MANUFACTURING GLASS BASE MATERIAL, METHOD FOR MANUFACTURING PREFORM FOR PRECISION PRESS-MOLDING, AND METHOD FOR MANUFACTURING GLASS OPTICAL ELEMENT

摘要

PROBLEM TO BE SOLVED: To provide a glass base material suitable for grinding and polishing processing, namely a method for manufacturing an optical element base material and a preform base material by using a reheating press-molding method, and methods for manufacturing a preform for precision press-molding and a glass optical element using the glass base material manufactured by the method. SOLUTION: The method for manufacturing a glass base material is characterized by using a press-molding die equipped with a body mold and an upper die and a lower die both of which are set in the body mold and face each other for pressing a glass material where the inner diameterϕLof a part where the lower die is set is smaller than the inner diameterϕUof a part where the upper die of the body mold is set, and introducing a heated and softened glass material into the press-molding die and press-molding. COPYRIGHT: (C)2011,JPO&INPIT