Polarized glass
US4549795A · kind A · utility
Inventor
Key dates
| Filing date | Mar 3, 1982 |
| Grant date | Oct 29, 1985 |
| Priority date | — |
| Expiry date | Mar 3, 2002 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03C23/00
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Polarized ophthalmic glass lenses are made from conventional ophthalmic glass. This is accomplished by heating a sheet of ophthalmic glass, which includes a reducible metal oxide as part of its composition, to its softening point in a reducing atmosphere for a time interval sufficient to reduce the metal oxide to metal to a predetermined depth on at least one surface of the sheet. Following this reduction of the metal oxide, the sheet is held at an elevated temperature to permit the reduced oxides to nucleate. Then, the sheet is stretched in one direction to elongate the nucleated metal particles in parallel lines. The glass then is shaped, cut into lenses, permitted to cool, and the outer surface of the lens blanks are ground and polished in a conventional manner, leaving the stretched elongated metal particles on the inner surface thereof to create polarized ophthalmic lenses.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.