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1. (WO2018220937) ENDOSCOPE OBJECTIVE OPTICAL SYSTEM, ENDOSCOPE, AND ENDOSCOPE SYSTEM

Pub. No.:    WO/2018/220937    International Application No.:    PCT/JP2018/009232
Publication Date: Fri Dec 07 00:59:59 CET 2018 International Filing Date: Sat Mar 10 00:59:59 CET 2018
IPC: G02B 13/04
A61B 1/00
A61B 1/05
G02B 13/18
G02B 23/26
Applicants: OLYMPUS CORPORATION
オリンパス株式会社
Inventors: IGARASHI Tsutomu
五十嵐勉
Title: ENDOSCOPE OBJECTIVE OPTICAL SYSTEM, ENDOSCOPE, AND ENDOSCOPE SYSTEM
Abstract:
In order to provide an endoscope objective optical system, and endoscope, and an endoscope system that can be compatible with miniaturized implementation and that has good imaging performance with improved on-axis chromatic aberration, an endoscope objective optical system comprises, in order from the object side, a first lens L1 having a negative refractive power, an aperture diaphragm, and a second lens L2 having a positive refractive power, an image-side surface of the first lens L1 being concave toward the image side, an image-side surface of the second lens L2 being convex toward the image side, and the conditional expressions (1), (2), (3), (4), (5), (6), and (7) being satisfied. (1): 0.6 < LL1is/LsL2i < 1.25. (2): -3 < (LL1is/RL1i) × (LsL2i/RL2i) < -1.25. (3): -2 < fL22/(f × fL1) < -1.35. (4): 2 < (nd1 – 1.63) × (νd1 – 31). (5): 5 < (nd2 – 1.45) × (νd2 – 31). (6) 1.63 < nd1 and 31 < νd1. (7): 1.45 < nd2 and 31 < νd2.