Zoom optical system, optical instrument incorporating the zoom optical system, and method of manufacturing the zoom optical system
US7839577B2 · kind B2 · utility
7Cited by
11References
33Claims
0Family size
Assignee
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Key dates
| Filing date | Dec 23, 2008 |
| Grant date | Nov 23, 2010 |
| Priority date | — |
| Expiry date | Dec 23, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/646
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom optical system has a first lens group having a positive refracting power; a second lens group having a negative refracting power; a third lens group having a positive refracting power; a fourth lens group having a negative refracting power; and a fifth lens group having a positive refracting power, in the order from the object side. The fourth lens group is composed of a cemented lens of a negative lens and a positive lens in the order from the object side, and a condition of the following expression is satisfied: νp>30.0, where νp is an Abbe number of the positive lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.