Endoscope

Patent metadata

Field	Value
Publication number	US-2016367113-A1
Application number	US-201615250209-A
Country	US
Kind code	A1
Filing date	Aug 29, 2016
Priority date	Apr 10, 2014
Publication date	Dec 22, 2016
Grant date	—

Abstract

This endoscope includes an observation optical system capable of changing a magnified observation and a normal observation with each other, and a plurality of illumination optical systems, wherein a most tip side lens surface of at least one of the illumination optical systems is disposed at a position which is closer to a proximal end side than a most tip side lens surface of the observation optical system, and the following conditional expressions are satisfied.
0.03< D _Back(max)/ ft <2  (1)

1.05< ft/fw <5  (2)

In the expression, D_Back(max) is a maximum value of a distance between the most tip side lens surface and the most tip side lens surface, ft is a focal length in a close-distance magnified observation state, and fw is a focal length in a normal observation state.

First claim

1 . An endoscope comprising:
an observation optical system capable of changing a magnified observation state and a normal observation state with each other by moving part of lenses in an optical axis; and a plurality of illumination optical systems which radiate illumination light to an object, wherein a most tip side lens surface of at least one of the illumination optical systems is disposed at a position which is closer to a proximal end side of the endoscope than a most tip side lens surface of the observation optical system, and the following conditional expressions are satisfied,
0.03< D _Back(max)/ ft< 2  (1)

1.05< ft/fw< 5  (2)

wherein D_Back(max) is a maximum value [mm] of a distance between the most tip side lens surface of the illumination optical system and the most tip side lens surface of the observation optical system, ft is a focal length [mm] of the observation optical system in the magnified observation state, and fw is a focal length [mm] of the observation optical system in the normal observation state.

2 . The endoscope according to claim 1 , wherein the following conditional expression is satisfied,
0.01< D _Back(ave)/ ft< 1.0  (3)
wherein D_Back(ave) is an average value [mm] of the distances between the most tip side lens surfaces of all the illumination optical systems and the most tip side lens surface of the observation optical system.

3 . The endoscope according to claim 1 , wherein the following conditional expressions are satisfied,
0.02< D _Back(max)/2×tan( w ( t ))<1.0  (4)
−0.03> D _Back(max)/ FL _ L 01>−1.0  (5)
wherein w(t) is a field of view of the observation optical system during the magnified observation state, and FL_L01 is a focal length [mm] of a most tip side lens of the observation optical system.

4 . The endoscope according to claim 3 , wherein the following conditional expressions are satisfied,
0.01< D _Back(ave)/2×tan( w ( t ))<5.0  (6)
−0.03> D _Back(ave)/ FL _ L 01>−1.0  (7)
wherein D_Back(ave) is an average value [mm] of the distances between the most tip side lens surfaces of all the illumination optical systems and the most tip side lens surface of the observation optical system.

Assignees

• Olympus Corp

Inventors

• Katakura Masahiro

Classifications

• A61B1/06

  with illuminating arrangements · CPC title

• G02B23/2469

  using optical fibres · CPC title

• G02B23/2438

  Zoom objectives · CPC title

• G02B23/243

  Objectives for endoscopes · CPC title

• A61B1/07

  using light-conductive means, e.g. optical fibres · CPC title