Patent ID: 6764972
Filing Date: 2004-07-20
Classification: C03C,G02B,Y10S

Abstract:
A mother glass composition for graded index lenses, which comprises the following glass components:40 to 60 mol % SiO2, 2 to 12 mol % TiO2, 2 to 22 mol % MgO, 12 to 20 mol % Li2O, 2 to 13 mol % Na2O, 0 to 10 mol % GeO2, 0 to 10 mol % B2O3, and 0 to 5 mol % Al2O3, and further comprises:0 to 5 mol % ZnO, 0 to 7 mol % Y2O3, 0 to 7 mol % Nb2O5, 0 to 7 mol % In2O3, 1 to 5 mol % ZrO2, 0 to 16 mol % BaO, 0 to 5 mol % SnO2, and 1 to 5 mol % Ta2O5, provided that the total content of ZnO, Y2O3, Nb2O5, and In2O3 is from 0 to 18 mol %, the molar ratio of the Ta2O5 content to the ZrO2 content is from 0.2 to 2.5, the molar ratio of the MgO content to the BaO content is from 0.4 to 2.5 and the mother glass composition does not contain lead oxide.