Zoom lens
US5056900A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 10, 1990 |
| Grant date | Oct 15, 1991 |
| Priority date | — |
| Expiry date | Oct 10, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/144109
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens comprising a first lens unit of positive power, a second lens unit of negative power as the variator, a third lens unit of negative power as the compensator, and a fourth lens unit of positive power stationary during zooming, the fourth lens unit being composed of a bi-convex first lens, a positive second lens, a negative third lens of strong concave curvature at the front, a positive fourth lens, a fifth lens of strong concave curvature at the rear, and a positive sixth lens, and satisfying the following condition: EQU 0.5<D/Fw<1.5 where D is the air separation between the fourth and fifth lenses, and Fw is the shortest focal length of the entire lens system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.