Zoom lens
US8054560B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 30, 2010 |
| Grant date | Nov 8, 2011 |
| Priority date | — |
| Expiry date | Mar 30, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/144113
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens includes a first, a second, a third and a fourth lens groups that are arranged along an optical axis and from an object side to an image side in sequence. The refractive powers of the four lens groups are positive, negative, positive and positive, respectively. The first and the third lens groups are fixed at a fixed position. The second lens group is movable along the optical axis in accordance with the change of magnification. The fourth lens group is movable along the optical axis in accordance with keeping an image plane fixed at an image sensor. The present invention has at least four pieces of lens that are made of plastic material in order to decrease camera lens weight and move easily the lens groups. In addition, the present invention has small variation of aperture value, moderate zoom ratio and compact size at the same time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.