Zoom lens system
US8279530B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Dec 20, 2010 |
| Grant date | Oct 2, 2012 |
| Priority date | — |
| Expiry date | Apr 25, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/145113
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens system is used for imaging an object to an image plane. The system, in the order from the object side to the image plane, includes a first lens group with positive refraction power, a second lens group with negative refraction power, a third lens group with positive refraction power, an aperture stop, a fourth lens group with positive refraction power, and a fifth lens group with negative refraction power. The fifth lens group comprises a lens of negative refraction power and a lens of positive refraction power. The system satisfies the formulas: −0.18<f2/ft<−0.13; and V11−V12<20, wherein, f2 is the effective focal length of the second lens group, ft is the effective focal length of the system in the telescopic state, V11 is the Abbe number of the lens of negative refraction power, and V12 is the Abbe number the lens of positive refraction power.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.