Photochromic naphthopyran compositions of neutral color
US5753146A · kind A · utility
69Cited by
22References
34Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 29, 1996 |
| Grant date | May 19, 1998 |
| Priority date | — |
| Expiry date | Mar 29, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B5/23
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Described are novel compositions of a carrier and at least two photochromic naphthopyran compounds, selected on the basis of specific criteria, that when exposed to solar ultraviolet radiation, exhibit neutral colors of gray or brown contained within the a* and b* ranges of +10 to -10 in the CIELAB color system. Also described are carriers, i.e., organic solvents and organic polymeric host materials, such as optically clear articles, e.g., ophthalmic lenses or other plastic transparencies that contain or that are coated with the naphthopyran compounds.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.