Reducing stray light in lensed optical systems
US4989960A · kind A · utility
19Cited by
6References
5Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Aug 18, 1988 |
| Grant date | Feb 5, 1991 |
| Priority date | — |
| Expiry date | Aug 18, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/0018
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical lens has a blackened layer in its outer surface which extends to a depth sufficient to substantially eliminate reflected stray light in the lens. The blackened layer is formed by causing hydrogen under pressure to react for a predetermined time and temperature with a metal oxide of the optical material thereby leaving the metal oxide in its reduced form in the lens. Some of the oxides are reduced completely, leaving the metal in its elemental form in the layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.