Glasses with very high refractive index
AssigneeCorning Incorporated
InventorMarie Jacqueline Monique Comte
Life of this patent
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Abstract
The invention concerns glasses that have a refractive index of more than 1.880, an Abbe number of more than or equal to 30.4, and a density of more than 4.1, and having the following chemical composition, expressed in wt. %, based on the oxides: SiO.sub.2 : 6-9, B.sub.2 O.sub.3 : 15-19, with SiO.sub.2 +B.sub.2 O.sub.3 <26, Nb.sub.2 O.sub.5 : 12 to <20.5, ZrO.sub.2 : 8-10, TiO.sub.2 : 7-11, La.sub.2 O.sub.3 : 23-32, with ZrO.sub.2 +TiO.sub.2 +La.sub.2 O.sub.3 : .gtoreq.44, CaO: 8 to <13, SrO: 0-2, BaO: 0-2, MgO: 0-2, ZnO: 0-5, with CaO+SrO+BaO+MgO+ZnO: .gtoreq.9, Y.sub.2 O.sub.3 : 0-5, WO.sub.3 : 0-5, Li.sub.2 O+Na.sub.2 O+K.sub.2 O: 0-2, others 0-1.
Claims6
Glasses possessing a refractive index of more than 1.880, an Abbe number of at least 30.4, and a density of more than 4.1, and consisting essentially of the following component oxides within the indicated ranges, expressed in wt. %:
- ______________________________________ SiO.sub.2 6-9 B.sub.2 O.sub.3 15-19 with SiO.sub.2 + B.sub.2 O.sub.3 <26 Nb.sub.2 O.sub.5 12 to <20.5 ZrO.sub.2 8-10 TiO.sub.2 7-11 La.sub.2 O.sub.3 23-32 with ZrO.sub.2 + TiO.sub.2 + La.sub.2 O.sub.3 .gtoreq.44 Y.sub.2 O.sub.3 0-5 WO.sub.3 0-5 CaO 8 to <13 SrO 0-2 BaO 0-2 MgO 0-2 ZnO 0-5 with CaO + SrO + BaO + MgO + ZnO .gtoreq.9 Li.sub.2 O + Na.sub.2 O + K.sub.2 O 0-2 Others 0-1. ______________________________________
Dependencies are inferred from the claim text.