| 摘要 |
This invention is directed to the production of glasses essentially free of Nb2O5, and having refractive index close to 1.7, an Abbe number of about 35 and a density close to 3.2. The glasses consist essentially in weight percent on the oxide basis, of SiO2 38-45, TiO2 15-<20, ZrO2 6-10, La2O3 0.5-4, BaO 12-19, CaO 3-8, BaO+CaO+SrO 17-25, Na2O 2-6, K2O 4-8, Li2O+Na2O+K2O 6-10.5. |
