High refractive index glasses, multifocal corrective lenses containing same
US6284687A · kind A · utility
2Cited by
4References
9Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 7, 2000 |
| Grant date | Sep 4, 2001 |
| Priority date | — |
| Expiry date | Apr 7, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S501/903
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The present invention relates to glasses of high refractive index having the following composition of oxides, expressed in percentages by weight: SiO.sub.2 29-35, B.sub.2 O.sub.3 0.5-5, Li.sub.2 O 0.5-3, Na.sub.2 O 4-8, K.sub.2 O 0-2, PbO 28-40, BaO 4-14, La.sub.2 O.sub.3 4-12, TiO.sub.2 3-8, ZnO 0-8, ZrO.sub.2 0-4, Nb.sub.2 O.sub.5 0-5, with: Li.sub.2 O+Na.sub.2 O+K.sub.2 O 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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.