Zoom lens
US5760967A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 22, 1994 |
| Grant date | Jun 2, 1998 |
| Priority date | — |
| Expiry date | Nov 22, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/144113
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens comprising, from front to rear, a first lens unit of positive refractive power, a second lens unit of negative refractive power for varying the focal length, a third lens unit of positive or negative refractive power for compensating for the image shift with zooming, an aperture stop and a fourth lens unit having the image forming function and stationary during zooming, wherein the first lens unit has a front lens sub-unit of negative refractive power, a first lens sub-unit of positive refractive power and a second lens sub-unit of positive refractive power, and wherein during focusing from an infinitely distant object to an object at the minimum distance, at least the first and second lens sub-units are axially moved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.