IR fast low light level lens system
US5386315A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 4, 1993 |
| Grant date | Jan 31, 1995 |
| Priority date | — |
| Expiry date | Jun 4, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/14
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A compound lens for use in a low light level system operating in the near-infrared region. The lens system includes a high light-gathering ability requiring both a large aperture and good transmissivity over the wavelengths of interest. A wide field of view (e.g., 50.degree.) without excessive chromatic and geometric aberrations that generally accompanies systems with a large aperture is provided. Space is provided in the lens system for a variable iris and variable density spot subassembly. Desired optical quantities are obtained through the use of zinc selenide as the material for an aspheric lens. The use of this diamond-turnable infrared material as a field lens yields exceptional performance for a fast (e.g., F/1.25) lens with a wide field of view.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.