Optical glass for precision molding having high refractive index

摘要

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.