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Patent Searching and Data


Title:
OBJECTIVE OPTICAL SYSTEM FOR ENDOSCOPE
Document Type and Number:
WIPO Patent Application WO/2018/235352
Kind Code:
A1
Abstract:
The purpose of the present invention is to provide an objective optical system for an endoscope, the objective optical system having a small F number, small size and high image formation performance, being resistant to manufacturing errors, and easily suppressing occurrence of flare. This objective optical system for an endoscope comprises, in order from the object side, a first lens L1 having negative refractive power, a second lens L2 having positive refractive power, an aperture stop S, a third lens L3 having positive refractive power, a fourth lens L4 having positive refractive power, a fifth lens L5 having negative refractive power, and a sixth lens L6 having positive refractive power, wherein the second lens L2 is a meniscus lens with a convex surface facing the image side, the third lens L3 is a meniscus lens with a convex surface facing the image side, a cemented lens having positive refractive power is formed by the fourth lens L4 and the fifth lens L5, the six lens L6 is joined to an imaging element, and the following conditional expression (1) is satisfied. (1): 0.55≤(r3f+r3r)/(r3f-r3r)≤5 Herein, r3f is the curvature radius of an object-side surface of the third lens, and r3r is the curvature radius of an image-side surface of the third lens.

Inventors:
KAMO Yuji (2951 Ishikawa-machi, Hachioji-sh, Tokyo 07, 〒1928507, JP)
TSUJI Yoshifumi (2951 Ishikawa-machi, Hachioji-sh, Tokyo 07, 〒1928507, JP)
Application Number:
JP2018/009237
Publication Date:
December 27, 2018
Filing Date:
March 09, 2018
Export Citation:
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Assignee:
OLYMPUS CORPORATION (2951, Ishikawa-machi Hachioji-sh, Tokyo 07, 〒1928507, JP)
International Classes:
G02B13/04; A61B1/00; A61B1/05; G02B23/26
Domestic Patent References:
WO2016204001A12016-12-22
WO2016031586A12016-03-03
WO2011145505A12011-11-24
WO2018042797A12018-03-08
Foreign References:
JPH0274912A1990-03-14
JPH06222263A1994-08-12
Attorney, Agent or Firm:
SAITO Keisuke (Surugadai-shita MK Bldg. 6F, 41-3 Kanda-jimbocho 1-chome, Chiyoda-k, Tokyo 51, 〒1010051, JP)
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