Projection lens
US4767199A · kind A · utility
20Cited by
2References
4Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 21, 1986 |
| Grant date | Aug 30, 1988 |
| Priority date | — |
| Expiry date | Apr 21, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/16
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A projection lens for projecting an image appearing on a cathode-ray tube onto a screen, small in residual aberrations, having a high imaging performance, also having a large aperture ratio and a wide field angle, suitable for a video projector having a high definition of, say, 1,125 scanning lines. The projection lens has, successively from the screen side, a Gauss type lens system, a positive lens mainly for enlarging the aperture ratio, and a negative lens mainly for widening the field angle, which negative lens has a strongly concave surface at the screen end.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.