Optical and ophthalmic glass with refractive indices greater than or equal to 1.56, Abbe numbers greater than or equal to 40 and densities less than or equal to 2.70 g/cm3

摘要

An optical and ophthalmic glass with high refractive index, high Abbe number and low density, which is distinguished by good chemical stability, good crystallization behavior and capability for chemical hardening, comprises (in % by weight): SiO2-47 to 75 B2O3-1 to 20 Al2O3-0 to 10 P2O5-0 to 5 Li2O-0 to 15 Na2O-0 to 10 K2O-0 to 10 CaO-0 to 20 MgO-0 to 15 SrO-0 to 4 BaO-0 to 4 ZnO-0 to 5 TiO2-1 to 15 ZrO2-0 to 8 Nb2O5-0 to 5 and F--0 to 5.