Lenses unit for endoscope, and endoscope equipped with the same

Patent metadata

Field	Value
Publication number	US-2016178884-A1
Application number	US-201514927152-A
Country	US
Kind code	A1
Filing date	Oct 29, 2015
Priority date	Dec 22, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

A lenses unit for an endoscope includes a lens barrel; a lens serving as a front group lens and lenses serving as a rear group lens, which are housed inside the lens barrel; and an aperture arranged between the front group lens and the rear group lens. An imaging-side final surface of the rear group lens has a structure in which the imaging-side final surface is fixed to a cover glass of an image pickup device with an adhesive layer. A focal distance f F of the front group lens, a focal distance f B of the rear group lens, a focal distance f el of an entire optical lenses group, a total optical length OL of the optical lenses group, and a metal back MB of the optical lenses group satisfy a relationship of f el /f F <0, f el /f B >0, and OL/MB>7.0.

First claim

What is claimed is:

1 . A lenses unit used for an endoscope, comprising:
a lens barrel; a front group lens and a rear group lens housed inside the lens barrel; and an aperture arranged between the front group lens and the rear group lens, wherein an imaging-side final surface of the rear group lens has a structure in which the imaging-side final surface is fixed to a cover glass of an image pickup device with an adhesive layer, and wherein a focal distance f F of the front group lens, a focal distance f B of the rear group lens, a focal distance f el of an entire optical lenses group including the front group lens and the rear group lens, a total optical length OL of the optical lenses group, and a metal back MB of the optical lenses group satisfy a relationship of f el /f F <0, f el /f B >0, and OL/MB>7.0.

2 . The lenses unit of claim 1 ,
wherein a curvature radius rLbR 2 of the imaging-side final surface of the rear group lens is rLbR 2 ≠∞, and wherein a refractive index n be of a final lens of the rear group lens on an imaging side and a refractive index n ad of the adhesive layer when the rear group lens is fixed by the adhesive layer are n be ≠n ad .

3 . The lenses unit of claim 1 ,
wherein an Abbe number v be of a final lens of the rear group lens on an imaging side is v be >25, and wherein a refractive index n be of a final lens of the rear group lens on the imaging side is 1.40<n be <1.90.

4 . The lenses unit of claim 1 ,
wherein the forefront surface of the front group lens on a photographic subject side is a concave surface or a convex surface, and a sag amount d of the concave surface or the convex surface and a lens external diameter φ of the optical lenses group satisfy a relationship of −0.1<d/φ<0.1.

5 . An endoscope comprising:
a lenses unit; an image pickup device in which an imaging surface is covered with a cover glass; an imaging-side final surface of the rear group lens in the lenses unit for an endoscope; and an adhesive layer formed by an adhesive resin with which the cover glass of the image pickup device is fixed, wherein the lenses unit includes: a lens barrel; a front group lens and a rear group lens housed inside the lens barrel; and an aperture arranged between the front group lens and the rear group lens, wherein an imaging-side final surface of the rear group lens has a structure in which the imaging-side final surface is fixed to the cover glass of the image pickup device with the adhesive layer, and wherein a focal distance f F of the front group lens, a focal distance f B of the rear group lens, a focal distance f el of an entire optical lenses group including the front group lens and the rear group lens, a total optical length OL of the optical lenses group, and a metal back MB of the optical lenses group satisfy a relationship of f el /f F <0, f el /f B >0, and OL/MB>7.0.

6 . The endoscope of claim 5 ,
wherein a curvature radius rLbR 2 of the imaging-side final surface of the rear group lens is rLbR 2 ≠∞, and wherein a refractive index n be of a final lens of the rear group lens on an imaging side and a refractive index n ad of the adhesive layer when the rear group lens is fixed by the adhesive layer are n be ≠n ad .

7 . The endoscope of claim 5 ,
wherein an Abbe number v be of a final lens of the rear group lens on an imaging side is v be >25, and wherein a refractive index n be of a final lens of the rear group lens on the imaging side is 1.40<n be <1.90.

8 . The endoscope of claim 5 ,
wherein the forefront surface of the front group lens on a photographic subject side is a concave surface or a convex surface, and a sag amount d of the concave surface or the convex surface and a lens external diameter φ of the optical lenses group satisfy a relationship of −0.1<d/φ<0.1.

9 . An endoscope comprising:
a lens unit including a lens barrel, a front group lens and a rear group lens housed inside the lens barrel, and an aperture arranged between the front group lens and the rear group lens; an imaging element in which an imaging surface is covered with cover glass; an adhesive layer formed by an adhesive resin with which an imaging-side final surface of the rear group lens in the lens unit and the cover glass of the imaging element are fixed, wherein the imaging-side final surface of the rear group lens and an imaging-side end surface of the lens barrel are structured so as to be fixed to the cover glass via the adhesive layer, and wherein a focal distance f F of the front group lens, a focal distance f B of the rear group lens, a focal distance f el of an entire optical system including the front group lens, the rear group lens, the adhesive layer, and the cover glass, a total optical length OL corresponding to a distance from a forefront surface of the front group lens on a photographic subject side to an imaging-side rear end surface of the cover glass, and a metal back MB corresponding to a distance from the imaging-side final surface of the rear group lens to a front end surface of the cover glass on the photographic subject side satisfy a relationship of f el /f F <0, f el /f B >0, and OL/MB>7.0.

10 . The endoscope of claim 9 ,
wherein at least an imaging-side end portion of the lens barrel, the adhesive layer, and the cover glass are covered with mold resin.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Hanada Yasuyuki
• Miyanishi Saturo
• Osada Akinori
• Matsumura Yoshio

Classifications

• G02B23/243 Primary

  Objectives for endoscopes · CPC title

• A61B1/0011

  Manufacturing of endoscope parts · CPC title

• G02B27/0025

  for optical correction, e.g. distorsion, aberration · CPC title

• G02B7/021

  for more than one lens · CPC title

• G02B23/2484

  Arrangements in relation to a camera or imaging device (processing or control of video signals generated by an endoscope H04N23/60, H04N23/70) · CPC title