Zoom lens system
US6101045A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 22, 1997 |
| Grant date | Aug 8, 2000 |
| Priority date | — |
| Expiry date | Sep 22, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/143103
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens system has from an object side a first lens group of a positive refractive power, a second lens group of a positive refractive power and a third lens group of a negative refractive power. The second lens group has from the object side a lens unit and a positive lens element convex to the object side. Focusing for a close object is performed by moving the lens unit toward the object side. In the zoom lens, the following condition is fulfilled: ##EQU1## where r1 is a radius of curvature of an object side surface of the positive lens element and r2 is a radius of curvature of an image side surface of the positive lens element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.