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Title:
OBJECTIVE OPTICAL SYSTEM FOR ENDOSCOPE
Document Type and Number:
WIPO Patent Application WO/2019/198362
Kind Code:
A1
Abstract:
The purpose of the present invention is to provide a compact and high resolution objective optical system for an endoscope such that degradation of optical performance due to manufacturing errors is mitigated. Provided is an objective optical system comprising, in order from the object side, a positive first lens group G1, a negative second lens group G2, and a positive third lens group G3, and configured such that zooming and focusing is performed by moving at least the second group G2 along an optical axis AX when transitioning from a normal observation state to a magnified-image observation state, the objective optical system being characterized in that the first group G1 comprises, in order from the object side, a negative plano-concave lens L1 with the planar surface facing the object side and two cemented lenses CL1, CL2, and the following conditional expression (1) is satisfied: -3.6 < f1 / fz1 < -2 (1) where f1 represents the focal distance of the negative plano-concave lens L1, and fz1 represents the focal distance of the entire objective optical system for an endoscope in a normal observation state.

Inventors:
EGUCHI YOSUKE (JP)
Application Number:
JP2019/007467
Publication Date:
October 17, 2019
Filing Date:
February 27, 2019
Export Citation:
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Assignee:
OLYMPUS CORP (JP)
International Classes:
G02B13/04; A61B1/00; G02B23/26
Domestic Patent References:
WO2014129089A12014-08-28
WO2016084494A12016-06-02
WO2017199614A12017-11-23
Foreign References:
JP2012226248A2012-11-15
Attorney, Agent or Firm:
SAITO Keisuke (JP)
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