An optical glass for precision press molding.

摘要

An optical glass for precision press molding, having good chemical durability and optical constants, i.e. a sag temperature (At) of at most 550 DEG C, a refractive index (nd) of 1.625 to 1.690 and an Abbe number ( nu d) of at least 57, which can be subjected to precision press molding at a temperature of at most 600 DEG C and thus is useful for the production of an aspherical lens is provided, which has a chemical composition (% by weight) comprising: SiO2 2 to 13 % B2O3 11 to 25 % SiO2 + B2O3 23 to 30 % LaF3 5 to 30 % Gd2O3 4 to 13 % Y2O3 4 to 13 % BaF2 22 to 45 % Li2O 0 to 6 % LiF 0 to 8 % Li2O + LiF 0.5 to 8 % o