Title:
OPTICAL SYSTEM OF OBJECT FOR ENDOSCOPE
Document Type and Number:
WIPO Patent Application WO/2016/208367
Kind Code:
A1
Abstract:
Provided is an optical system of an object for an endoscope that is compatible with miniaturization of the optical system and increased resolution of an imaging element, is robust against variations in performance within manufacturing error, and is not susceptible to degradation in peripheral resolution. The optical system of an object for an endoscope comprises, in order from the object side, a first group G1 having a positive refractive power, a brightness aperture S, and a second group G2 having a positive refractive power. The first group G1 comprises a first lens L1 in which the object side thereof is a flat surface, the first lens L1 having a negative refractive power, and a second lens L2 having a positive refractive power. The second group G2 comprises a cemented lens CL, the cemented lens CL comprising a third lens L3 having a positive refractive power and a fourth lens L4 having a negative refractive power. The optical system satisfies the following conditional formulae (1), (2), (3), and (4). 0.13≤La/Lb≤0.17 (1), -2.7≤f4/f≤-2.2 (2), -0.7≤(ne2×f2)/(ne4×f4)≤0 (3), 2.5≤νd3/νd4≤3.5 (4)
Inventors:
EGUCHI YOSUKE (JP)
Application Number:
PCT/JP2016/066675
Publication Date:
December 29, 2016
Filing Date:
June 03, 2016
Export Citation:
Assignee:
OLYMPUS CORP (JP)
International Classes:
G02B13/04; A61B1/00; G02B23/26
Domestic Patent References:
| WO2013077139A1 | 2013-05-30 |
Foreign References:
| JP5374667B1 | 2013-12-25 | |||
| JPH08286128A | 1996-11-01 |
Attorney, Agent or Firm:
SAITO Keisuke et al. (JP)
Keisuke Saito (JP)
Keisuke Saito (JP)
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