Colorless ophthalmic glasses
US5525553A · kind A · utility
Inventors
Key dates
| Filing date | Jun 5, 1995 |
| Grant date | Jun 11, 1996 |
| Priority date | — |
| Expiry date | Jun 5, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S501/903
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
This invention is directed to the production of glasses useful for ophthalmic applications which exhibit excellent resistance to the development of coloration upon being exposed to x-radiation and excellent resistance to the development of solarization. The glass compositions are essentially free of lead and consist essentially, in weight percent, of ______________________________________ SiO.sub.2 60-70 ZrO.sub.2 0.5-2 TiO.sub.2 0-1.5 B.sub.2 O.sub.3 0.5-5 CeO.sub.2 0.1-0.3 Sb.sub.2 O.sub.3 0-0.5 Al.sub.2 O.sub.3 2-6 Li.sub.2 O 0-2 SO.sub.3 0-0.3 Na.sub.2 O 9-14 MgO 0-5 Br 0-0.5 K.sub.2 O 3-10 SrO 0-5 Cl 0-0.5 CaO 0.5-4 BaO 0-5 F 0-0.5. ZnO 3-9 ______________________________________
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.