Title:
ENDOSCOPE OBJECTIVE OPTICAL SYSTEM
Document Type and Number:
WIPO Patent Application WO/2017/217146
Kind Code:
A1
Abstract:
Provided is a compact and high-performance endoscope objective optical system which has a large f-number and which is less likely to be influenced by a manufacturing error. The endoscope objective optical system is characterized by comprising, from the object side, a negative first lens L1, a positive second meniscus lens L2 having a convex surface facing the image side, a brightness stop S, a positive third lens L3, and a cemented lens CL1 composed of a positive fourth lens L4 and a negative fifth lens L5, in this order, and by satisfying the following conditional expressions: -0.6≤f1/f45≤-0.18 (1-1); 0.2≤(r3f+r3r)/(r3f-r3r)≤1 (1-2); and 0.15≤d34/d4≤0.7 (1-3), wherein f1 represents the focal distance of the first lens L1, f45 represents the composite focal distance of the fourth lens L4 and the fifth lens L5, r3f represents the curvature radius, on the object side, of the third lens L3, r3r represents the curvature radius, on the image side, of the third lens L3, d34 represents the distance, along an optical axis, between the third lens L3 and the fourth lens L4, and d4 represents the thickness of the fourth lens L4.
Inventors:
KAMO YUJI (JP)
TSUJI YOSHIFUMI (JP)
TSUJI YOSHIFUMI (JP)
Application Number:
PCT/JP2017/017747
Publication Date:
December 21, 2017
Filing Date:
May 10, 2017
Export Citation:
Assignee:
OLYMPUS CORP (JP)
International Classes:
G02B13/04
Domestic Patent References:
| WO2011145505A1 | 2011-11-24 | |||
| WO2016031586A1 | 2016-03-03 |
Foreign References:
| JP2009109576A | 2009-05-21 |
Attorney, Agent or Firm:
SAITO Keisuke et al. (JP)
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