Ion exchangeable segment glass
US3997249A · kind A · utility
9Cited by
5References
4Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 28, 1975 |
| Grant date | Dec 14, 1976 |
| Priority date | — |
| Expiry date | Oct 28, 1995 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/315
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
There is disclosed an ion exchange-strengthened ophthalmic segment glass suitable for the fabrication of fused bifocal and trifocal ophthalmic lenses. More particularly, there is disclosed a lanthanum-silicate based ophthalmic segment glass having indices of refraction of about 1.57 to about 1.65 which is suitable for chemical ion exchange strengthening so as to develop a compressively-stressed ion-exchanged surface layer having a depth of at least 60 micrometers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.