High index ophthalmic glasses
US5162826A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 17, 1991 |
| Grant date | Nov 10, 1992 |
| Priority date | — |
| Expiry date | Jun 17, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S501/903
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
This invention relates to the production of glasses exhibiting a refractive index between about 1.66-1.81, a softening point between about 625.degree.-675.degree. C., a strain point between about 455.degree.-490.degree. C., a linear coefficeint of thermal expansion (25.degree.-300.degree. C.) between about 53-65.times.10.sup.-7 /.degree.C., and good chemical durability which consist essentially, in weight percent, of: ______________________________________ SiO.sub.2 24-42 Li.sub.2 O 0.2 Li.sub.2 O + Na.sub.2 O + K.sub.2 O 0-3.5 Al.sub.2 O.sub.3 3-7.5 Na.sub.2 O 0-2 ZrO.sub.2 0-2.5 B.sub.2 O.sub.3 2-7.5 K.sub.2 O 0-3 TiO.sub.2 0-8 PbO 35-57 La.sub.2 O.sub.3 0-8 La.sub.2 O.sub.3 + ZrO.sub.2 4-12.sub.2 ______________________________________
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.