Zoom lens barrel based on the vari-focal optical system
US5576894A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 19, 1994 |
| Grant date | Nov 19, 1996 |
| Priority date | — |
| Expiry date | Oct 19, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/10
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens barrel based on the vari-focal optical system includes a zoom cam ring which is supported only rotatably about the optical axis and a focus cam ring which is supported movably only in the axial direction both fitted on a fixed tube inside a lens barrel. For the alteration of the lens focal length, the zoom cam ring is turned to carry out zooming, and for the focusing of an object, the focus cam ring is moved in the axial direction to carry out focusing, thereby preventing the interference between zooming and focusing caused by the movement of the lens sets. A drive mechanism based on a piezo-electric element is used to move the focus cam ring in the axial direction, thereby simplifying the structure and reducing the weight.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.