Lens element incorporating narrow bandpass filter and usable in dual mode
US4106855A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 12, 1977 |
| Grant date | Aug 15, 1978 |
| Priority date | — |
| Expiry date | May 12, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B17/0896
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical system utilizing a lens element having a spherical surface incorporating a narrow bandpass filter, with the spherical surface being of such configuration that converging rays are normal to its surface, thereby permitting the narrow bandpass filter to operate with minimum bandwith, thus maximizing the rejection of unwanted background radiation. The surface of the lens element opposite the surface having the narrow bandpass filter may incorporate a dichroic filter, enabling the lens element to operate in a dual mode, with the dichroic filter reflecting entering visible light energy but being transparent to laser light energy, and the narrow bandpass filter thereafter eliminating wavelengths outside a given laser spectrum. As an example, my novel lens element may be used as a part of a catadioptric objective system sensitive to both visible and laser light frequencies.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.