Amber photochromic glasses
US5482901A · kind A · utility
4Cited by
13References
10Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 15, 1994 |
| Grant date | Jan 9, 1996 |
| Priority date | — |
| Expiry date | Jul 15, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03C4/06
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A surface-reduced photochromic glass containing silver halide crystals, having an original transmittance of 60-75%, a darkened transmittance of less than 30% at 25.degree. C., a faded transmittance equal to the darkened transmittance plus at least 25% and a value of at least 50%, a position in a color mixture diagram between 575 and 585 nm, the glass composition having a Na.sub.2 O content of at least 1% in its surface, or containing as additives 1-6 ppm Pd, or a combination of 2-10 ppm Au and up to 0.9% Er.sub.2 O.sub.3. The glass may be chemically strengthened and generally has a longer dominant wavelength when so treated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.