Objective lens system with aspheric Fresnel elements
US4293196A · kind A · utility
21Cited by
4References
31Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Aug 13, 1979 |
| Grant date | Oct 6, 1981 |
| Priority date | — |
| Expiry date | Aug 13, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B3/08
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A high speed projection lens system particularly adaptable for a television projection system having a viewing screen and a video image forming surface is provided. The projection lens system includes a first thin meniscus lens element convex to the projection screen having an aspherical Fresnel type surface; a second thin meniscus lens element concave to the projection screen having an aspherical Fresnel type surface and a weak third thin aspherical meniscus lens element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.