Image-taking apparatus
US6977778B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 24, 2004 |
| Grant date | Dec 20, 2005 |
| Priority date | — |
| Expiry date | Jun 24, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/143507
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens system for forming an optical image of a subject on the image-sensing surface of an image sensor has three lens units, namely, from the object side thereof, a first lens unit having a negative optical power, a second lens unit having a positive optical power, and a third lens unit having a positive optical power, and achieves zooming by varying the distances between the individual lens units in such a way that, during zooming from the wide-angle end to the telephoto end, the distance between the first and second lens units decreases. The first lens unit is composed of two or more lens elements, and the first lens element, i.e., the lens element disposed at the object-side end of the first lens unit, is a plastic lens element. Moreover, a prescribed conditional formula is fulfilled.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.