Mass

摘要

As for this invention, mass of oxide standard % with, SiO_2:35 - 45%, B₂ O_3:12 - 20%, Li₂ O: 2 - 7%, ZnO: 0.1 - 10%, Al₂ O_3:2 - 15%, BaO: 10 - 40%, K₂ O: 0 - 5%, Na₂ O: 0 - 10%, and, the Gd₂ O_3:0 - 20%, to contain, at the same time, SiO₂ +B2O3: 47 - 58%, Li₂ O+Na2O+K2O: The optical glass which is 5 - 14% is offered.