Imaging system, image capturing apparatus and electronic device

Patent metadata

Field	Value
Publication number	US-2016259147-A1
Application number	US-201514727302-A
Country	US
Kind code	A1
Filing date	Jun 1, 2015
Priority date	Mar 2, 2015
Publication date	Sep 8, 2016
Grant date	—

Abstract

An imaging system includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element and a fifth lens element. The first lens element with positive refractive power has an object-side surface being convex in a paraxial region thereof. The second lens element with negative refractive power has an image-side surface being concave in a paraxial region thereof. The third lens element has refractive power. The fourth lens element with refractive power has an image-side surface being concave in a paraxial region thereof. The fifth lens element with refractive power has an object-side surface being convex in a paraxial region thereof and an image-side surface being concave in a paraxial region thereof.

First claim

What is claimed is:

1 . An imaging system comprising, in order from an object side to an image side:
a first lens element with positive refractive power having an object-side surface being convex in a paraxial region thereof; a second lens element with negative refractive power having an image-side surface being concave in a paraxial region thereof; a third lens element having refractive power; a fourth lens element with refractive power having an image-side surface being concave in a paraxial region thereof, wherein an object-side surface and the image-side surface of the fourth lens element are aspheric, and the image-side surface of the fourth lens element comprises at least one convex shape in an off-axial region thereof; and a fifth lens element with refractive power having an object-side surface being convex in a paraxial region thereof and an image-side surface being concave in a paraxial region thereof, wherein the object-side surface and the image-side surface of the fifth lens element are aspheric, and the image-side surface of the fifth lens element comprises at least one convex shape in an off-axial region thereof; wherein the imaging system has a total of five lens elements with refractive power, there is an air gap between any two of the first lens element, the second lens element, the third lens element, the fourth lens element and the fifth lens element that are adjacent to each other, a central thickness of the fourth lens element is CT 4 , an axial distance between the third lens element and the fourth lens element is T 34 , an axial distance between the fourth lens element and the fifth lens element is T 45 , a focal length of the imaging system is f, a curvature radius of an object-side surface of the third lens element is R 5 , a curvature radius of an image-side surface of the third lens element is R 6 , an Abbe number of the second lens element is V 2 , an Abbe number of the third lens element is V 3 , an Abbe number of the fourth lens element is V 4 , and the following conditions are satisfied:
CT 4/ T 34<1.20;
CT 4/ T 45<1.60;
| f/R 5|+| f/R 6|<1.10; and
1.75<( V 2+ V 4)/ V 3.

2 . The imaging system of claim 1 , wherein the object-side surface of the fourth lens element is convex in a paraxial region thereof.

3 . The imaging system of claim 2 , wherein the Abbe number of the third lens element is V 3 , and the following condition is satisfied:
V 3<30.

4 . The imaging system of claim 2 , wherein the central thickness of the fourth lens element is CT 4 , the axial distance between the third lens element and the fourth lens element is T 34 , and the following condition is satisfied:
CT 4/ T 34<1.0.

5 . The imaging system of claim 1 , wherein the central thickness of the fourth lens element is CT 4 , the axial distance between the fourth lens element and the fifth lens element is T 45 , and the following condition is satisfied:
CT 4/ T 45<1.48.

6 . The imaging system of claim 1 , wherein the central thickness of the fourth lens element is CT 4 , the axial distance between the fourth lens element and the fifth lens element is T 45 , and the following condition is satisfied:
CT 4/ T 45<1.25.

7 . The imaging system of claim 1 , wherein the third lens element has positive refractive power.

8 . The imaging system of claim 1 , wherein the first lens element has an image-side surface being concave in a paraxial region thereof.

9 . The imaging system of claim 1 , wherein a curvature radius of the object-side surface of the fourth lens element is R 7 , the focal length of the imaging system is f, and the following condition is satisfied:
| R 7| f|< 3.0.

10 . The imaging system of claim 9 , wherein an f-number of the imaging system is Fno, an axial distance between the object-side surface of the first lens element and an image surface is TL, a half of a maximal field of view of the imaging system is HFOV, and the following conditions are satisfied:
1.6< Fno< 2.4; TL< 6 mm; and 35 degrees< HFOV.

11 . The imaging system of claim 1 , wherein a curvature radius of the object-side surface of the fourth lens element is R 7 , the focal length of the imaging system is f, and the following condition is satisfied:
| R 7| f|< 2.3.

12 . The imaging system of claim 1 , wherein the focal length of the imaging system is f, a focal length of the third lens element is f 3 , a focal length of the fourth lens element is f 4 , a focal length of the fifth lens element is f 5 , and the following condition is satisfied:
| f/f 3|+| f/f 4|+| f/f 5|<0.60.

13 . The imaging system of claim 1 , wherein a focal length of the first lens element is f 1 , a focal length of the second lens element is f 2 , a focal length of the third lens element is f 3 , a focal length of the fourth lens element is f 4 , a focal length of the fifth lens element is f 5 , and the following conditions are satisfied:
| f 3|>| f 1|; | f 3|>| f 2|; | f 3|>| f 4|; and | f 3|>| f 5|.

14 . The imaging system of claim 1 , wherein a curvature radius of the object-side surface of the fourth lens element is R 7 , a curvature radius of the image-side surface of the fourth lens element is R 8 , a curvature radius of the object-side surface of the fifth lens element is R 9 , a curvature radius of the image-side surface of the fifth lens element is R 10 , the focal length of the imaging system is f, and the following condition is satisfied:
(| R 7|+| R 8|+| R 9|+| R 10|)/ f< 3.5.

15 . The imaging system of claim 1 , wherein the axial distance between the third lens element and the fourth lens element is T 34 , the axial distance between the fourth lens element and the fifth lens element is T 45 , a sum of axial distances between any two of the first lens element, the second lens element, the third lens element, the fourth lens element and the fifth lens element that are adjacent to each other is ΣAT, and the following condition is satisfied:
0.60<( T 34+ T 45)/Σ AT< 0.80.

16 . The imaging system of claim 1 , wherein the Abbe number of the second lens element is V 2 , the Abbe number of the third lens element is V 3 , the Abbe number of the fourth lens element is V 4 , and the following condition is satisfied:
V 2+ V 3+ V 4<90.

17 . The imaging system of claim 1 , wherein a central thickness of the first lens element is CT 1 , a central thickness of the second lens element is CT 2 , a central thickness of the third lens element is CT 3 , the central thickness of the fourth lens element is CT 4 , a central thickness of the fifth lens element is CT 5 , and CT 5 is larger than CT 1 , CT 2 , CT 3 , and CT 4 .

18 . The imaging system of claim 1 , wherein a central thickness of the second lens element is CT 2 , a central thickness of the third lens element is CT 3 , the central thickness of the fourth lens element is CT 4 , a central thickness of the fifth lens element is CT 5 , and the following condition is satisfied:
( CT 2+ CT 3+ CT 4)/ CT 5<1.25.

19 . The imaging system of claim 1 , wherein a curvature radius of the image-side surface of the fourth lens element is R 8 , a curvature radius of the object-side surface of the fifth lens element is R 9 , and the following condition is satisfied:
1.20< R 8/ R 9.

20 . The imaging system of claim 1 , wherein the focal length of the imaging system is f, the curvature radius of the object-side surface of the third lens element is R 5 , the curvature radius of the image-side surface

Assignees

• Largan Precision Co Ltd

Inventors

• Hsueh Chun-Che
• Chen Wei-Yu

Classifications

• G02B9/60

  having five components only · CPC title

• G02B13/0045 Primary

  having five or more lenses · CPC title

• H04N5/2254

  Electricity · mapped topic