WIDE ANGLE OPTICAL SYSTEM AND ENDOSCOPE

WIPO Patent Application WO/2016/013302

A1

The purpose of the present invention is to sufficiently correct chromatic aberration of magnification through a common optical element in the later stage while aligning the direction of an image of all fields of view. A wide angle optical system (3) comprises a first group (6) having negative and positive lenses (4, 5) with negative refractive power, a second group (7) having a reflective-refractive optical element (14), and a third group (8). The reflective-refractive optical element (14) includes a first surface (11) on the object side, having a first transmitting surface (11a) and a first reflecting surface (11b) disposed surrounding the first transmitting surface, a second surface (12) on the image side, having a second transmitting surface (12a) and a second reflecting surface (12b) disposed surrounding the second transmitting surface, and a third surface (13) that is a conical transmitting surface disposed between the first surface (11) and the second surface (12) and having an apex angle toward the object. The wide angle optical system (3) satisfies the following expression: νn > νp α/2 > 90° − θk Where νn represents the Abbe number of the negative lens (4), νp represents the Abbe number of the positive lens (5), α represents the angle of the apex angle on the third surface (13), and θk represents a half field angle (0 <θk < 90°) of principal ray in the minimum angle of view within the lateral field of view.

MIZUSAWA MASAYUKI (JP)

PCT/JP2015/065990

January 28, 2016

June 03, 2015

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OLYMPUS CORP (JP)

G02B13/04; A61B1/00; G02B13/18; G02B17/08; G02B23/26

WO2008153114A1	2008-12-18
WO2014088076A1	2014-06-12
WO2010084914A1	2010-07-29

See also references of EP 3173836A4

UEDA, Kunio et al. (JP)
Ueda Kunio (JP)

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