Zoom lens
US7652827B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 28, 2008 |
| Grant date | Jan 26, 2010 |
| Priority date | — |
| Expiry date | Jul 1, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/1425
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens includes a first and a second lens group respectively having negative and positive refractive power, and changes a focal length by changing a distance between the first and the second lens group. The second lens group includes a first lens having positive refractive power and a convex surface, a second lens having positive refractive power, an aspheric surface, and a convex surface, a third lens having negative refractive power, a fourth lens having positive refractive power, and a fifth lens including one lens or more having positive refractive power. The third and the fourth lenses are connected, and the zoom lens satisfies Nd21>1.8 and νd24>80, where Nd21 is a refractive index of the first lens of the second lens group at a d-line, and νd24 is an Abbe number of the fourth lens of the second lens group at a d-line.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.