Title:
OBSERVATION OPTICAL SYSTEM AND OBSERVATION DEVICE HAVING SAME
Document Type and Number:
WIPO Patent Application WO/2018/117025
Kind Code:
A1
Abstract:
An observation optical system according to the present invention comprises a Fresnel lens, and a lens LP having positive refractive power and provided on the light incidence side or light emission side of the Fresnel lens, wherein the length in an optical axis direction from a surface vertex of a central zone of the Fresnel lens to an end of the central zone thereof is denoted by h0, the length in the optical axis direction of a grating wall surface of a first zone adjacent to the central zone is denoted by h1, and both the lengths are appropriately set.
Inventors:
EBE HIROKI (JP)
Application Number:
PCT/JP2017/045313
Publication Date:
June 28, 2018
Filing Date:
December 18, 2017
Export Citation:
Assignee:
CANON KK (JP)
International Classes:
G02B25/00; G02B13/18; G02B27/02
Foreign References:
| JPH0391708A | 1991-04-17 | |||
| JPH05210054A | 1993-08-20 | |||
| US20100024275A1 | 2010-02-04 | |||
| US20120243110A1 | 2012-09-27 | |||
| JPH0829690A | 1996-02-02 | |||
| JPH10186230A | 1998-07-14 |
Attorney, Agent or Firm:
OKABE Yuzuru et al. (JP)
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