US Patent 7943540 Optical glass for precision molding having high refractive index

An optical glass for precision molding having a high refractive index (nd) and a low yield temperature (At). The optical glass comprises, as glass components in wt %, 64 to 83% of Bi2O3; 4 to 17% of B2O3; 0 to 12% of GeO2 (wherein the total of B2O3 and GeO2 is 10 to 20%); 0 to 7% of La2O3; 0 to 7% of Gd2O3 (wherein the total of La2O3 and Gd2O3 is 1 to 13%); 0 to 4% of ZrO2; 0 to 5% of Ta2O5; 0 to 15% of ZnO; 0 to 2% of Sb2O3; and 0 to 1% of In2O3. The optical glass has optical constants, that is, a refractive index (nd) of 2.05 to 2.25 and an Abbe number (vd) of 15 to 22, and a yield temperature (At) of 510° C. or less.