Optical imaging system

Patent metadata

Field	Value
Publication number	US-2016320688-A1
Application number	US-201615204728-A
Country	US
Kind code	A1
Filing date	Jul 7, 2016
Priority date	Aug 7, 2014
Publication date	Nov 3, 2016
Grant date	—

Abstract

An optical imaging system according to the present invention includes, in order from an object side to an image side, a first lens with negative refractive power, a second lens that is a meniscus lens having a convex image-side surface, an aperture stop, a third lens with positive refractive power, and a lens group with positive refractive power. When the center thickness of the first lens is represented as t1, the center thickness of the second lens is represented as t2 and the focal length of the whole system is represented as f,
t 1/ f >1.2 and
t 2/ f >1.2
are satisfied.

First claim

What is claimed is:

1 . An optical imaging system comprising, in order from an object side to an image side, a first lens with negative refractive power, a second lens that is a meniscus lens having a convex image-side surface, an aperture stop, a third lens with positive refractive power, and a lens group with positive refractive power, wherein when the center thickness of the first lens is represented as t1, the center thickness of the second lens is represented as t2 and the focal length of the whole system is represented as f,
t 1/ f> 1.2 and t 2/ f> 1.2 are satisfied.

2 . An optical imaging system according to claim 1 , further comprising a filter immediately in front of or immediately behind the aperture stop.

3 . An optical imaging system according to claim 1 , configured such that angles of incidence onto the aperture surface of all rays of any light beam which enters the optical imaging system and the principal ray of which is at any angle with respect to the optical axis, from 0 to the half angle of view are 25 degrees or less.

4 . An optical imaging system according to claim 1 , configured such that the F-number is 1.1 or less.

5 . An optical imaging system according to claim 1 , configured such that the aperture radius is greater than the image height.

6 . An optical imaging system according to claim 1 , configured such that the half angle of view is 45 degrees or more and 55 degrees or less.

7 . An optical imaging system comprising, in order from an object side to an image side, a first lens with negative refractive power, a second lens that is a meniscus lens having a convex image-side surface, an aperture stop, a third lens with positive refractive power, and a lens group with positive refractive power, wherein the lens group consists of a fourth lens with positive refractive power and when the center thickness of the second lens is represented as t2 and the focal length of the whole system is represented as f,
t 2/ f> 1.2 is satisfied.

8 . An optical imaging system according to claim 7 , further comprising a filter immediately in front of or immediately behind the aperture stop.

9 . An optical imaging system according to claim 7 , configured such that angles of incidence onto the aperture surface of all rays of any light beam which enters the optical imaging system and the principal ray of which is at any angle with respect to the optical axis, from 0 to the half angle of view are 25 degrees or less.

10 . An optical imaging system according to claim 7 , configured such that the F-number is 1.1 or less.

11 . An optical imaging system according to claim 7 , configured such that the aperture radius is greater than the image height.

12 . An optical imaging system according to claim 7 , configured such that the half angle of view is 45 degrees or more and 55 degrees or less.

13 . An optical imaging system comprising, in order from an object side to an image side, a first lens with negative refractive power, a second lens that is a meniscus lens having a convex image-side surface, an aperture stop, a third lens with positive refractive power, and a lens group with positive refractive power, wherein the lens group consists of a fourth lens with negative refractive power and a fifth lens with positive refractive power and when the center thickness of the second lens is represented as t2, the focal length of the fourth lens is f4 and the focal length of the whole system is represented as f,
t 2/ f> 1.2 and f 4/ f<− 4 are satisfied.

14 . An optical imaging system according to claim 13 , further comprising a filter immediately in front of or immediately behind the aperture stop.

15 . An optical imaging system according to claim 13 , configured such that angles of incidence onto the aperture surface of all rays of any light beam which enters the optical imaging system and the principal ray of which is at any angle with respect to the optical axis, from 0 to the half angle of view are 25 degrees or less.

16 . An optical imaging system according to claim 13 , configured such that the F-number is 1.1 or less.

17 . An optical imaging system according to claim 13 , configured such that the aperture radius is greater than the image height.

18 . An optical imaging system according to claim 13 , configured such that the half angle of view is 45 degrees or more and 55 degrees or less.

Assignees

• Nalux Co Ltd

Inventors

• Sakagami Norihisa

Classifications

• G02B13/22

  Telecentric objectives or lens systems · CPC title

• G02B13/04

  Reversed telephoto objectives · CPC title

• G03B11/00 Primary

  Filters or other obturators specially adapted for photographic purposes · CPC title

• G02B13/18

  with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration {(G02B13/002 takes precedence)} · CPC title

• G02B9/34

  having four components only · CPC title