Method for manufacturing a porous glass film

Abstract

The present invention provides an optical member having a high transmittance, wherein a composition change of a phase-separable base material glass film is suppressed. A method for manufacturing an optical member provided with a porous glass film on the base member includes the steps of forming a glass powder film containing a glass powder on the base member, forming a phase-separable base material glass film on the base member by heating and fusing the glass powder film in an atmosphere having an oxygen concentration of more than 20%, forming a phase-separated glass film on the base member by heating the base material glass film, and forming a porous glass film on the base member by subjecting the phase-separated glass film to an etching treatment.

Dependencies are inferred from the claim text.