# US 10,307,044 B2 · Endoscope illuminating optical system

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- Number: US 10,307,044 B2
- Document ID: US10307044B2
- Status: Granted
- Kind: B2
- Application number: 15/822,659
- Filed: 2017-11-27
- Published: 2018-03-22
- Granted: 2019-06-04
- Earliest claimed: 2015-09-09
- Assignees: Olympus Corporation
- Applicants: Olympus Corporation
- Inventors: Tsutomu Igarashi
- Web page: https://patentgrep.com/patent/US10307044B2

## CPC

- A61B 1/06: with illuminating arrangements
- A61B 1/00096: {Optical elements}
- A61B 1/05: characterised by the image sensor, e.g. camera, being in the distal end portion
- A61B 1/0661: {Endoscope light sources}
- A61B 1/0669: {at proximal end of an endoscope}
- A61B 1/0676: {at distal tip of an endoscope}
- A61B 1/07: using light-conductive means, e.g. optical fibres
- G02B 23/243: {Objectives for endoscopes}
- G02B 23/2469: {using optical fibres}
- G02B 23/26: using light guides {(for illumination G02B23/2469)}
- A61B 1/0607: {for annular illumination}
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

An endoscope illuminating optical system to be disposed at a front end of an insertion portion of an endoscope includes a lens formed by a transparent-resin molding having a function of a front-end frame, which is configured to be disposed at a front-end side of the insertion portion, and a light guide which is disposed adjacent to the lens. A surface of the lens facing the light guide is a composite concave surface in which two axisymmetric concave surfaces are overlapped, and has a gourd-shaped effective cross-section. An effective range of a distal end surface of the light guide has a shape of an ellipsoid, or an oval, or a gourd, and has a long axis in a longitudinal direction of the gourd-shaped effective cross-section of the surface of the lens facing the light guide side, and a short axis in a direction perpendicular to the long axis. The cross-section of the composite concave surface includes an end surface of the light guide.

## Claims

### Claim 1

An endoscope illuminating optical system to be disposed at a front end of an insertion portion of an endoscope, the endoscope illuminating optical system comprising:
a lens formed by a transparent-resin molding having a function of a front-end frame, which is configured to be disposed at a front-end side of the insertion portion; and
a light guide which is disposed adjacent to the lens, wherein:
a surface of the lens facing toward the light guide is a composite concave surface in which two axisymmetric concave surfaces are overlapped, and has a gourd-shaped effective cross-section,
an effective range of a distal end surface of the light guide has a shape of an ellipsoid, or an oval, or a gourd, and has a long axis in a longitudinal direction of the gourd-shaped effective cross-section of the surface of the lens facing toward light guide, and a short axis in a direction perpendicular to the long axis,
the cross-section of the composite concave surface includes the distal end surface of the light guide, and
the endoscope illuminating optical system satisfies the following conditional expressions (1), (2), and (3):
1.2<Llgl/Llgs<4 (1)
0.25<R′/√(Llgl/×Llgs)<0.6 (2)
0.4<Lofs/(Llgl-Llgs)<1.3 (3)
where:
Llgl denotes a maximum length in a long-axis direction of the distal end surface of the light guide,
Llgs denotes a maximum length in a short-axis direction of the distal end surface of the light guide,
R′ denotes a radius of curvature at a practical center of the axisymmetric concave surfaces, and
Lofs denotes a distance between axes of the two axisymmetric concave surfaces.

### Claim 2 (depends on 1)

The endoscope illuminating optical system according to claim 1, wherein the axisymmetric concave surfaces which form the composite concave surface are made of an aspheric surfaces, and satisfy the following conditional expression (4):
(Z(H)−Zr′(H))/R′<−0.01 (4)
where:
H=0.9×R′,
H denotes a height from an optical axis at the axisymmetric concave surfaces,
Z(H) denotes an amount of displacement in an optical axial direction at the height H of the axisymmetric concave surfaces, and
Zr′(H) denotes an amount of displacement in the optical axial direction at the height H on a spherical surface of the radius of curvature R′ at the practical center.