Photochromic glasses
US6162749A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 29, 1999 |
| Grant date | Dec 19, 2000 |
| Priority date | — |
| Expiry date | Jul 29, 2019 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03C3/11
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The invention concerns photochromic glasses with improved properties having the following composition, in wt. %: SiO.sub.2 : 51-66, B.sub.2 O.sub.3 : 15-23, Al.sub.2 O.sub.3 : 3-10, ZrO.sub.2 : 2.5-11, TiO.sub.2 : 0-1, Li.sub.2 O: 3-7, Na.sub.2 O: 0-8, K.sub.2 O: 2-9, Ag: 0.080-0.30, CuO>0.0020-0.0130, Cl: 0.1-0.6, Br 0.040-0.3, MgO: 0-3, CaO: 0-3, SrO: 0-3, BaO: 0-3, Nb.sub.2 O.sub.5 : 0-1, La.sub.2 O.sub.3 : 0-8, Y.sub.2 O.sub.3 : 0-8, with 0.2<Ag/(Cl+Br).ltoreq.0.5, Br/(Cl+Br)>0.15, 0.5.ltoreq.La.sub.2 O.sub.3 +Y.sub.2 O.sub.3.ltoreq.8, TiO.sub.2 +Nb.sub.2 O.sub.5 .ltoreq.1.2, 10.ltoreq.Al.sub.2 O.sub.3 +ZrO.sub.2 .ltoreq.17, MgO+CaO+SrO+BaO.ltoreq.6. Use for the production of ophthalmic lenses.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.