Photochromically colored object
US6102543A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 30, 1997 |
| Grant date | Aug 15, 2000 |
| Priority date | — |
| Expiry date | Dec 30, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02C7/102
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Disclosed is an object made of plastic material, in particular a plastic ophthalmic lens, colored with at least one photochromic substance which is also excited by light in the UV range of the spectrum and has a higher absorption in the excited state, judged by the spectral light sensitivity of the human eye, than in the not excited state and to which, in addition, at least one UV absorbing material is added in such a concentration that darkening of the photochromic substance(s) is independent of the UV fraction of the excitation light. But rather the intensity of the darkening depends on brightness, i.e. the intensity integrated over the spectral light sensitivity of the human eye V.sub.2.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.