Highly refractive, ThO.sub.2 -free optical glasses having refractive indices of 1.86-1.94 and Abbe-index numbers greater than or equal to 30
AssigneeSchott Glaswerke
InventorsKarl Mennemann, Danuta Grabowski
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Abstract
Highly refractive, ThO.sub.2 -free optical glasses having refractive indices of 1.86-1.94 and Abbe-index numbers greater than or equal to 30, comprise: ______________________________________ B.sub.2 O.sub.3 17-24 SiO.sub.2 0.5-6 B.sub.2 O.sub.3 + SiO.sub.2 19-27 La.sub.2 O.sub.3 40.1-51 ZrO.sub.2 5-9 Nb.sub.2 O.sub.5 0.5-25 Ta.sub.2 O.sub.5 0-27 Nb.sub.2 O.sub.5 + Ta.sub.2 O.sub.5 14-27 TiO.sub.2 0-8 PbO 0-12 ZnO 0-4 Al.sub.2 O.sub.3 0-2 ______________________________________
Claims6
An essentially ThO.sub.2 -- and Ta.sub.2 O.sub.5 --free optical glass of the system B.sub.2 O.sub.3 --SiO.sub.2 --La.sub.2 O.sub.3 --ZrO.sub.2 --Nb.sub.2 O.sub.5 having a refractive index of 1.86-1.94 and an Abbe number greater than or equal to 30, and high devitrification stability consisting of, in % by weight:
- ______________________________________ B.sub.2 O.sub.3 17-24 SiO.sub.2 0.5-6 B.sub.2 O.sub.3 + SiO.sub.2 19-27 La.sub.2 O.sub.3 40.1-51 ZrO.sub.2 5-9 Nb.sub.2 O.sub.5 0.5-25 TiO.sub.2 0-8 PbO 0-12 ZnO 0-4 Al.sub.2 O.sub.3 0-2 ______________________________________
Dependencies are inferred from the claim text.