Spectacle lenses to reduce discomfort from aphakia and certain eye diseases
US4284686A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 9, 1980 |
| Grant date | Aug 18, 1981 |
| Priority date | — |
| Expiry date | Jun 9, 2000 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/315
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
This invention is concerned with producing glasses suitable for use as spectacle lenses for aphakics or for persons subject to photoretinitis or retinitis pigmentosa. The glasses exhibit near-zero transmittance of radiations having wavelengths shorter than a selected cutoff wavelength ranging about 440-550 nm and the transmittance of the remainder of the visible spectrum is adjusted through the glass demonstrating photochromic behavior. The inventive method contemplates exposing photochromic glass within a narrowly-defined composition range to a strongly-reducing atmosphere at temperatures between about 350.degree.-520.degree. C. for a period of time of at least 12 hours to develop an integral colored surface layer on the glass.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.