Zoom lens
US5691851A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 23, 1996 |
| Grant date | Nov 25, 1997 |
| Priority date | — |
| Expiry date | Oct 23, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/142
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens is disclosed, comprising a front lens group having a first, a second and a third lens units, totaling at least three lens units, and whose overall refractive power for the wide angle end is positive and a rear lens group having a lens unit of positive refractive power and another lens unit of negative refractive power, wherein when zooming from the wide angle to the telephoto end, the first, the second and the third lens units all axially move in such relation that the overall refractive power of the front lens group is weaker in the telephoto end than in the wide angle end, and the lens units in the rear lens group all axially move in such relation that their separation narrows.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.