Title:
VARIABLE MAGNIFICATION OPTICAL SYSTEM, OPTICAL DEVICE, AND METHOD FOR MANUFACTURING VARIABLE MAGNIFICATION OPTICAL SYSTEM
Document Type and Number:
WIPO Patent Application WO/2021/039697
Kind Code:
A1
Abstract:
This variable magnification optical system comprises a front lens group and a rear lens group, which are arranged in order from the object side along an optical axis, and the rear lens group includes a first focusing lens group having positive refractive power, and a second focusing lens group disposed on the image surface side of the first focusing lens group and having negative refractive power. When the magnification is changed, the spacing between lens groups adjacent to each other changes, at the time of changing from focusing on an object at infinity to focusing on an object at a short distance, the position of the front lens group is fixed, the first focusing lens group and the second focusing lens group respectively move to the image surface side along different trajectories, and the following conditional expression is satisfied. 0.05 < (-fF2)/ft < 0.50 where fF2 is the focal length of the second focusing lens group, and ft is the focal length of the variable magnification optical system in a telephoto end state.
Inventors:
MURATANI MAMI (JP)
Application Number:
PCT/JP2020/031788
Publication Date:
March 04, 2021
Filing Date:
August 24, 2020
Export Citation:
Assignee:
NIKON CORP (JP)
International Classes:
G02B15/20
Domestic Patent References:
| WO2018139160A1 | 2018-08-02 |
Foreign References:
| JP2014102462A | 2014-06-05 | |||
| JPH03225308A | 1991-10-04 | |||
| JP2017219643A | 2017-12-14 | |||
| JP2015197593A | 2015-11-09 |
Attorney, Agent or Firm:
OHNISHI, Shogo et al. (JP)
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