High refractive index glasses, multifocal corrective lenses containing same
AssigneeCorning Incorporated
InventorsMarie M. J. Comte, Paulo Marques
Life of this patent
Estimating the term…
Abstract
The present invention relates to glasses of high refractive index having the following composition of oxides, expressed in percentages by weight: SiO2 29-35, B2O3 0.5-5, Li2O 0.5-3, Na2O 4-8, K2O 0-2, PbO 28-40, BaO 4-14, La2O3 4-12, TiO2 3-8, ZnO 0-8, ZrO2 0-4, Nb2O5 0-5, with: Li2O+Na2O+K2O 5.5-9; their use for the production of segments for multifocal corrective lenses; and multifocal corrective lenses incorporating at least one such segment in their structure.
Claims9
High refractive index glasses having the following composition of oxides, expressed in percentages by weight:
- SiO2 29-35 B2O3 0.5-5 Li2O 0.5-3 Na2O 4-8 K2O 0-2 PbO 28-40 BaO 4-14 La2O3 4-12 TiO2 3-8 ZnO 0-8 ZrO2 0-4 Nb2O5 0-5 with:
- Li2O + Na2O + K2O 5.5-9.
A glass segment for incorporation in a multifocal, ophthalmic lens, wherein the glass segment has a refractive index n of 1.70≦n≦1.78, and a composition of oxides, expressed in percentage by weight, in which at least 95% consists essentially of:
- SiO2 29-35 B2O3 0.5-5 Li2O 0.5-3 Na2O 4-8 K2O 0-2 PbO 28-40 BaO 4-14 La2O3 4-12 TiO2 3-8 ZnO 0-8 ZrO2 0-4 Nb2O5 0-5 with:
- Li2O + Na2O + K2O 5.5-9.
Dependencies are inferred from the claim text.