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US 5,288,669 AGranted
Glasses with very high index of refraction and low density
AssigneeCorning France
InventorsLuc Grateau, Pascale Laborde, Michel Prassas
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AssigneeCorning France
InventorsLuc Grateau, Pascale Laborde, Michel Prassas
Estimating the term…
This invention relates to glasses exhibiting refractive indices higher than 1.880, Abbe numbers of at least 29, densities lower than 4.1, good chemical durability and stability against devitrification, and an integrated transmission over the range of 380-800 nm at a thickness of 10 mm greater than 79%, the glasses consisting essentially, expressed in terms of weight percent on the oxide basis, of ______________________________________ SiO.sub.2 5-8 B.sub.2 O.sub.3 15-21 ZrO.sub.2 3-10 TiO.sub.2 7-17 Nb.sub.2 O.sub.5 20.5-26 ZrO.sub.2 + TiO.sub.2 + Nb.sub.2 O.sub.5 29-45 La.sub.2 O.sub.3 19-32 Y.sub.2 O.sub.3 0-9 CaO 8-16 SrO 0-5 BaO 0-5 MgO 0-5 CaO + SrO + BaO + MgO 8-16 ZnO 0-5 Li.sub.2 O 0-2 Na.sub.2 O 0-2 K.sub.2 O 0-2 Li.sub.2 O + Na.sub.2 O + K.sub.2 O 0-2. ______________________________________
Glasses characterized by the fact that they exhibit an index of refraction higher than 1.880, an Abbe number of at least 29, a density lower than 4.1 g/cm.sup.3, a good chemical durability and a lower tendency towards crystallization, and an integrated transmission from 380-800 nm--at a thickness of 10 mm--higher than 79%, these glasses consisting essentially, expressed in weight percent on the oxide basis, of
Dependencies are inferred from the claim text.