PRODUCTION APPARATUS OF GLASS PREFORM, PRODUCTION METHOD OF GLASS PREFORM, AND PRODUCTION METHOD OF OPTICAL ELEMENT

摘要

PROBLEM TO BE SOLVED: To produce inexpensively in large quantities a preform suitable for an optical element made of glass such as a plano-concave lens.SOLUTION: A production apparatus 1 of a glass preform which is a glass raw material for press molding for carrying out press molding by heating and softening includes: a melting crucible in which molten glass is formed by heating and melting a glass-making feedstock; a dropping pipe 2 through which molten glass is dropped intermittently; and a press part 14 for molding flatly a molten glass drop 16 dropped from the dropping pipe 2 by pressing it from the lateral side without supporting it from below.