Zoom lens
US7405885B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 3, 2007 |
| Grant date | Jul 29, 2008 |
| Priority date | — |
| Expiry date | Aug 3, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/1425
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens includes a first lens group with a negative refractive power and a second lens group with a positive refractive power. The first lens group includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence and refractive powers thereof are negative, negative, negative and positive respectively. The first and second lenses are meniscus lenses and two surfaces of the second lens are aspheric surfaces. The third lens is a biconcave lens and the fourth lens is a biconvex lens. The second lens group includes a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens arranged in sequence and refractive powers thereof are positive, positive, positive, negative and positive respectively. A cemented doublet lens is composed of the seventh and eighth lenses. The ninth lens is a biconvex lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.