Optical Glass

Glass with RI 1.85-1.96 and Abbe number 43-28 of composition (wt%): 10-17 B2O3, 20-55 La2O3, 0.5-38 Gd2O3, 0.5-32 WO3, 0-10 ZrO2, 0-30 Ta2O5, 0-55 SiO2, 0-5 GeO2, 0-5 Tb4O7, 0-38 Yb2O3, 0-3 SnO2, 0-5 Al2O3, 0-5 In2O3, 0-5 Bi2O3 and 0-2 MgO, CaO, SrO, ZnO, PbO and/or a fluoride or fluorides.