Zoom lens with extended variable focal length range
US4256371A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 18, 1979 |
| Grant date | Mar 17, 1981 |
| Priority date | — |
| Expiry date | Jun 18, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/22
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In the disclosed zoom lens a front lens group serves for focusing, a variator group and a compensator group for zooming and a fixed lens group for forming an image. In the basic focal length range the front lens group is fixed while the variator group and the front lens group are movable. In order to increase or decrease the focal length beyond the basic focal length range, the front lens group, the variator group and the compensator group are moved simultaneously. From the wide angle limit or from the telephoto limit of the basic focal length range through the extended range at both ends the front lens group and the variator group are moved simultaneously.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.