Invention Grant
- Patent Title: Variable magnification optical system, optical device, and production method for variable magnification optical system
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Application No.: US14700493Application Date: 2015-04-30
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Publication No.: US10168512B2Publication Date: 2019-01-01
- Inventor: Akihiko Obama , Tomoyuki Sashima
- Applicant: Nikon Corporation
- Applicant Address: JP Tokyo
- Assignee: Nikon Corporation
- Current Assignee: Nikon Corporation
- Current Assignee Address: JP Tokyo
- Agency: Shapiro, Gabor and Rosenberger, PLLC
- Priority: JP2012-238735 20121030; JP2012-238736 20121030
- Main IPC: G02B15/14
- IPC: G02B15/14

Abstract:
Composing, in order from an object side: a first lens group having positive refractive power; a second lens group having negative refractive power; and a third lens group having positive refractive power; upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group, a distance between the second lens group and the third lens group and a distance between the third lens group and an image plane being varied; on the most image side, a fixed lens group being fixed in a position upon zooming from the wide-angle end state to the telephoto end state; and the third lens group being moved in the direction of the optical axis upon focusing from an infinite distance object to a near distance object, thereby providing a small-size variable magnification optical system having a high zoom ratio and an excellent optical performance upon focusing from an infinite distance object to a near distance object, an optical apparatus, and a method for manufacturing the variable magnification optical system.
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