Title:
OBJECTIVE OPTICAL SYSTEM FOR ENDOSCOPE
Document Type and Number:
WIPO Patent Application WO/2016/067838
Kind Code:
A1
Abstract:
The purpose of the present invention is to provide an objective optical system for an endoscope, said objective optical system being provided with a long back focus and a focusing function, and having high-performance optical characteristics with minimal aberration variation associated with focusing and a small number of lenses. The objective optical system for an endoscope is provided with a first negative group G1, a second positive group G2, and a third positive group G3 in order from the object side. The third group G3 comprises a positive cemented lens CL2 and a positive lens L7 in order from the object side. The objective optical system for an endoscope can capture an image in a range from a normal observation state to a close observation state by moving the second group G2 along an optical axis AX, and satisfies the following conditional expression (1):
4 ≤ FB / f ≤ 7 (1)
Here, FB represents the back focus of the objective optical system for an endoscope, and f represents a focal length of the entire objective optical system for an endoscope in the normal observation state.
Inventors:
SATO SHINYA (JP)
Application Number:
PCT/JP2015/078195
Publication Date:
May 06, 2016
Filing Date:
October 05, 2015
Export Citation:
Assignee:
OLYMPUS CORP (JP)
International Classes:
G02B13/04
Domestic Patent References:
| WO2011070930A1 | 2011-06-16 | |||
| WO2013021744A1 | 2013-02-14 | |||
| WO2012169369A1 | 2012-12-13 | |||
| WO2010119640A1 | 2010-10-21 |
Foreign References:
| JP2008107391A | 2008-05-08 | |||
| JP2015036778A | 2015-02-23 |
Other References:
See also references of EP 3214475A4
Attorney, Agent or Firm:
SAITO Keisuke et al. (JP)
Keisuke Saito (JP)
Keisuke Saito (JP)
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