Wide angle narrow bandpass optical filter system
US4184749A · kind A · utility
23Cited by
1References
31Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jun 22, 1978 |
| Grant date | Jan 22, 1980 |
| Priority date | — |
| Expiry date | Jun 22, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B5/284
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A spherical lens element and a concentric lens element receive light, in that order, from a wide field of view, and diverge all rays so that upon leaving said concentric element, the angles of all rays approximate that of radial lines. This light is then filtered through a concentric narrow bandpass filter to attenuate undesired background light, and is collected by a suitable light collector and detector. Apertures for selecting the field of view and F number are provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.