Photochromic compounds
US4215010A · kind A · utility
181Cited by
3References
14Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 8, 1978 |
| Grant date | Jul 29, 1980 |
| Priority date | — |
| Expiry date | Sep 8, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02C7/02
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Photochromic compounds of the formula ##STR1## wherein one of R.sub.1 and R.sub.2 is halogen or lower alkoxy, and the other is hydrogen, and R.sub.3 and R.sub.4 are hydrogen, lower alkyl, lower alkoxy, or halogen and their use in lenses are disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.