Method of manufacturing glass optical elements

摘要

Disclosed is a method of manufacturing ultraprecise lenses, including aspherical lenses, not requiring grinding or polishing after press molding. The method comprises heating a glass material to a temperature corresponding to a glass viscosity of from 10⁵ to 10⁹ dPaS so that the glass material is softened, and press molding the glass material with the pressing molds which are heated to a temperature corresponding to a glass viscosity of from 10⁸ to 10¹² dPaS. Provided that the glass material is not heated to a temperature as high as that corresponding to a glass viscosity of 10⁵ dPaS when the pressing mold is heated to a temperature corresponding to a glass viscosity of 10⁸ and that the glass material is not heated to a temperature as low as that corresponding to a glass viscosity of 10⁹ dPaS when the pressing mold is heated to a temperature corresponding to a glass viscosity of 10¹² dPaS. The glass material to be molded comprises at least one selected from the group consisting of Nb₂O₃, WO₃, and TiO₂ and has a refractive index nd of greater than or equal to 1.65, an Abbè number (nu d) of less than or equal to 35, and a sag point (Ts) of less than or equal to 570° C. Each of the pressing molds comprises a film comprising carbon on a molding surface.