Lens system for a cathode ray tube projection system
US4824224A · kind A · utility
4Cited by
13References
28Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 31, 1986 |
| Grant date | Apr 25, 1989 |
| Priority date | — |
| Expiry date | Dec 31, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/18
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An improved lens system for a projection television is described. The lens system is designed to be used with a cathode ray tube having a face glass with an aspheric surface having phosphor elements mounted thereto. The aspheric surface of the face glass has its maximum radius at the optical axis and is of lesser radius outwardly thereof. From the screen, the lens system companies a first aspheric lens of relatively weak power, a second biconvex lens of relatively high positive power, a third aspheric lens of weak positive power and a fourth lens having a concave face on its screen sider and of relatively large negative power.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.