Method of forming mold release film and making a glass optical element

Abstract

In a method of forming a mold release film on the surface of a glass blank from which an optical element is made by press molding, a carbon film having a thickness of less than 50 angstroms or, preferably, less than 10 angstroms is formed on the surface of the glass blank, thereby improving the releasability of the mold and the molded article with respect to each other. A glass blank (1) is subjected to ashing with an oxygen plasma so as to remove organic dirt attached to the glass blank (1). Then, plasma cleaning with an argon plasma is effected so as to remove inorganic dirt attached to the glass blank (1). Thereafter, the glass blank (1) is subjected to methane plasma processing such that a carbon film (2) having a thickness of less than 50 angstroms is formed on the surface of the glass blank (1) from which the dirt has been removed.

Dependencies are inferred from the claim text.