Projection lens
US4950062A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 30, 1987 |
| Grant date | Aug 21, 1990 |
| Priority date | — |
| Expiry date | Dec 30, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/16
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A projection lens for projecting onto a screen an enlargement of an image appearing on a CRT wherein comma and chromatic aberration, which degrades imaging quality, can be properly corrected comprises 4 lens units. The projection lens comprises, in the order from the screen end, a first lens unit of positive optical power having a strong convex surface facing the screen end, a second lens unit comprising a biconvex lens element of positive optical power and a lens element of negative optical power having a concave surface facing the screen end, a third lens unit of positive optical power at an optical axis having a convex surface facing the screen end, and a fourth lens unit of negative optical power having a concave surface facing the screen end.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.