Patent ID: 7140205

Claim:
A method of manufacturing glass optical elements with a pair of opposed pressing molds, comprising: heating a glass material to a temperature corresponding to a glass viscosity of from 10 5 to 10 9 dPaS so that the glass material is softened, press molding the glass material with the pressing molds which are heated to a temperature corresponding to a glass viscosity of from 10 8 to 10 12 dPaS, wherein the glass material comprises at least one selected from the group consisting of Nb 2 O 3 , WO 3 , and TiO 2 and has a refractive index nd of greater than or equal to 1.65, an Abbènumber (νd) of less than or equal to 35, and a sag point (Ts) of less than or equal to 570° C., provided that the glass material is not heated to a temperature as high as that corresponding to a glass viscosity of 10 5 dPaS when the pressing mold is heated to a temperature corresponding to a glass viscosity of 10 8 and that the glass material is not heated to a temperature as low as that corresponding to a glass viscosity of 10 9 dPaS when the pressing mold is heated to a temperature corresponding to a glass viscosity of 10 12 dPaS, and that the press molding is carried out when the temperature of the glass material is 580° C. or lower.