Imaging lens system, image capturing device and electronic device

• US 9,411,133 B1
• Filed: 06/17/2015
• Issued: 08/09/2016
• Est. Priority Date: 02/02/2015
• Status: Active Grant

• Current Assignee: Largan Precision Co Limited (Largan Precision)
• Original Assignee: Largan Precision Co Limited (Largan Precision)
• Inventors: Hsieh, Dung-Yi, Huang, Hsin-Hsuan
• Primary Examiner(s): Lester, Evelyn A
• Application Number:
  US14/742,463
• Publication Number:
  US 20160223791A1
• Time in Patent Office: 419 Days
• Field of Search: 359/714, 359/739, 359/740, 359764-766
• US Class Current: 1/1
• CPC Class Codes: G02B 13/0015 characterised by the lens design
• CPC Class Codes: G02B 13/002 having at least one aspherical surface
• CPC Class Codes: G02B 13/0045 having five or more lenses
• CPC Class Codes: G02B 13/18 with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration G02B13/002 takes precedence
• CPC Class Codes: G02B 27/0025 for optical correction, e.g. distorsion, aberration
• CPC Class Codes: G02B 3/04 with continuous faces that are rotationally symmetrical but deviate from a true sphere , e.g. so called "aspheric" lenses
• CPC Class Codes: G02B 5/005 Diaphragms for cameras G03B9/02
• CPC Class Codes: G02B 9/60 having five components only

Abstract

This disclosure provides an imaging lens system, including, in order from an object side to an image side: a first lens element with positive refractive power having a convex object-side surface; a second lens element with negative refractive power; a third lens element with refractive power; a fourth lens element with refractive power having an object-side surface and an image-side surface thereof being aspheric; a fifth lens element with refractive power having a convex object-side surface, the object-side surface and an image-side surface thereof being aspheric, and at least one of the object-side surface and the image-side surface being provided with at least one inflection point. The imaging lens system is further provided with a stop, and no lens element with refractive power is disposed between the stop and first lens element.

Claims

1. An imaging lens system, including, in order from an object side to an image side:

a first lens element with positive refractive power having a convex object-side surface;

a second lens element with negative refractive power;

a third lens element with refractive power;

a fourth lens element with refractive power having an object-side surface and an image-side surface thereof being aspheric; and

a fifth lens element with refractive power having a convex object-side surface, the object-side surface and an image-side surface thereof both being aspheric, and at least one of the object-side surface and the image-side surface being provided with at least one inflection point;

wherein the imaging lens system is further provided with a stop, and no lens element with refractive power is disposed between the stop and the first lens element;

wherein the imaging lens system has a total of five lens elements with refractive power;

wherein an axial distance between the second lens element and the third lens element is T23, an axial distance between the third lens element and the fourth lens element is T34, a central thickness of the second lens element is CT2, a central thickness of the third lens element is CT3, a central thickness of the fourth lens element is CT4, a central thickness of the fifth lens element is CT5, a focal length of the imaging lens system is f, a focal length of the first lens element is f1, a focal length of the second lens element is f2, a focal length of the fourth lens element is f4, a focal length of the fifth lens element is f5, an axial distance between the stop and the image-side surface of the fifth lens element is SD, an axial distance between the object-side surface of the first lens element and the image-side surface of the fifth lens element is TD, and the following conditions are satisfied;

0.90<

(T23+T34)/(CT3+CT4+CT5);

(|f/f4|+|f/f5|)/(|f/f1|+|f/f2|)<

0.60;

0.7<

SD/TD<

1.1; and

1.0<

(CT2+CT4)/(CT2−

CT4).

2. The imaging lens system of claim 1, wherein the focal length of the first lens element is f1, the focal length of the fourth lens element is f4, and the following condition is satisfied:

−

1.0<

f1/f4<

0.

3. The imaging lens system of claim 2, wherein the second lens element has a concave image-side surface, and the object-side surface of the fourth lens element is concave.

4. The imaging lens system of claim 1, wherein an Abbe number of the first lens element is V1, an Abbe number of the second lens element is V2, an Abbe number of the fourth lens element is V4, and the following condition is satisfied:

0.5<

(V2+V4)/V1<

1.0.

5. The imaging lens system of claim 1, wherein the image-side surface of the fourth lens element is convex, and the image-side surface of the fifth lens element is concave.

6. The imaging lens system of claim 5, wherein the fifth lens element has negative refractive power.

7. The imaging lens system of claim 1, wherein the focal length of the imaging lens system is f, a maximum image height of the imaging lens system is ImgH, and the following condition is satisfied:

1.9<

f/ImgH<

5.0.

8. The imaging lens system of claim 7, wherein a curvature radius of the object-side surface of the fourth lens element is R7, a curvature radius of the image-side surface of the fourth lens element is R8, and the following condition is satisfied:

−

35<

(R7+R8)/(R7−

R8)<

−

1.0.

9. The imaging lens system of claim 7, wherein the maximum image height of the imaging lens system is ImgH, the axial distance between the second lens element and the third lens element is T23, the axial distance between the third lens element and the fourth lens element is T34, and the following condition is satisfied:

1.0<

ImgH/(T23+T34)<

2.2.

10. The imaging lens system of claim 1, wherein the second lens element has a convex object-side surface and a concave image-side surface.

11. The imaging lens system of claim 1, wherein the axial distance between the second lens element and the third lens element is T23, the axial distance between the third lens element and the fourth lens element is T34, the central thickness of the third lens element is CT3, the central thickness of the fourth lens element is CT4, the central thickness of the fifth lens element is CT5, and the following condition is satisfied:

1.0<

(T23+T34)/(CT3+CT4+CT5).

12. The imaging lens system of claim 1, wherein the central thickness of the second lens element is CT2, the central thickness of the fourth lens element is CT4, and the following condition is satisfied:

2.0<

(CT2+CT4)/(CT2−

CT4)<

50.

13. The imaging lens system of claim 1, wherein the focal length of the imaging lens system is f, the focal length of the first lens element is f1, the focal length of the second lens element is f2, and the following condition is satisfied:

2.5<

|f/f1|+|f/f2|.

14. The imaging lens system of claim 1, wherein the focal length of the imaging lens system is f, a vertical distance between a critical point on the image-side surface of the fifth lens element and an optical axis is Yc52, and the following condition is satisfied:

3.0<

f/Yc52<

20.

15. An image capturing device, including the imaging lens system of claim 1 and an image sensor.

16. An electronic device, including the image capturing device of claim 15.

17. An imaging lens system, including, in order from an object side to an image side:

a first lens element with positive refractive power having a convex object-side surface;

a second lens element with negative refractive power having a convex object-side surface and a concave image-side surface;

a third lens element with refractive power;

a fourth lens element with negative refractive power having an object-side surface and an image-side surface thereof being aspheric; and

a fifth lens element with refractive power having a concave image-side surface, an object-side surface and the image-side surface thereof being aspheric and at least one of the object-side surface and the image-side surface being provided with at least one inflection point;

wherein the imaging lens system is further provided with a stop, and no lens element with refractive power is disposed between the stop and the first lens element;

wherein the imaging lens system has a total of five lens elements with refractive power;

wherein an axial distance between the second lens element and the third lens element is T23, an axial distance between the third lens element and the fourth lens element is T34, a central thickness of the third lens element is CT3, a central thickness of the fourth lens element is CT4, a central thickness of the fifth lens element is CT5, a focal length of the imaging lens system is f, a focal length of the first lens element is f1, a focal length of the second lens element is f2, a focal length of the fourth lens element is f4, a focal length of the fifth lens element is f5, an axial distance between the stop and the image-side surface of the fifth lens element is SD, an axial distance between the object-side surface of the first lens element and the image-side surface of the fifth lens element is TD, and the following conditions are satisfied;

0.90<

(T23+T34)/(CT3+CT4+CT5);

(|f/f4|+|f/f5|)/(|f/f1|+|f/f2|)<

1.0;

0.7<

SD/TD<

1.1; and

0.3<

CT4/CT3<

2.5.

18. The imaging lens system of claim 17, wherein half of a maximal field of view of the imaging lens system is HFOV, and the following condition is satisfied:

10.0 [deg.]<

HFOV<

30.0 [deg.].

19. The imaging lens system of claim 18, wherein the object-side surface of the fourth lens element is concave, and the image-side surface of the fourth lens element is convex.

20. The imaging lens system of claim 18, wherein the third lens element has positive refractive power.

21. The imaging lens system of claim 17, wherein the focal length of the first lens element is f1, the focal length of the fourth lens element is f4, and the following condition is satisfied:

−

0.5<

f1/f4<

0.

22. The imaging lens system of claim 17, wherein the axial distance between the second lens element and the third lens element is T23, the axial distance between the third lens element and the fourth lens element is T34, the central thickness of the third lens element is CT3, the central thickness of the fourth lens element is CT4, the central thickness of the fifth lens element is CT5, and the following condition is satisfied:

1.0<

(T23+T34)/(CT3+CT4+CT5).

23. The imaging lens system of claim 17, wherein a maximum effective radius of the object-side surface of the first lens element is SD11, an entrance pupil diameter of the imaging lens system is EPD, and the following condition is satisfied:

0.95<

EPD/(SD11*2)<

1.1.

24. An imaging lens system, including, in order from an object side to an image side:

a first lens element with positive refractive power having a convex object-side surface;

a second lens element with negative refractive power;

a third lens element with refractive power;

a fourth lens element with negative refractive power having a concave object-side surface, the object-side surface and an image-side surface thereof being aspheric; and

a fifth lens element with refractive power having a concave image-side surface, an object-side surface and the image-side surface thereof being aspheric and at least one of the object-side surface and the image-side surface being provided with at least one inflection point;

wherein the imaging lens system is further provided with a stop, and no lens element with refractive power is disposed between the stop and the first lens element;

wherein the imaging lens system has a total of five lens elements with refractive power;

wherein an axial distance between the second lens element and the third lens element is T23, an axial distance between the third lens element and the fourth lens element is T34, a central thickness of the third lens element is CT3, a central thickness of the fourth lens element is CT4, a central thickness of the fifth lens element is CT5, a focal length of the imaging lens system is f, a focal length of the first lens element is f1, a focal length of the second lens element is f2, a focal length of the fourth lens element is f4, a focal length of the fifth lens element is f5, an axial distance between the stop and the image-side surface of the fifth lens element is SD, an axial distance between the object-side surface of the first lens element and the image-side surface of the fifth lens element is TD, and the following conditions are satisfied;

0.90<

(T23+T34)/(CT3+CT4+CT5);

(|f/f4|+|f/f5|)/(|f/f1|+|f/f2|)<

1.0;

0.7<

SD/TD<

1.1; and

0.3<

CT4/CT3<

2.5.

25. The imaging lens system of claim 24, wherein the second lens element has a concave image-side surface, at least one of object-side surfaces and image-side surfaces of the first lens element, the second lens element, the third lens element, the fourth lens element and the fifth lens element is aspheric, and the first lens element, the second lens element, the third lens element, the fourth lens element and the fifth lens element are all made of plastic material.

26. The imaging lens system of claim 25, wherein at least one of the object-side surface and the image-side surface of the third lens element is provided with at least one inflection point.

27. The imaging lens system of claim 25, wherein a curvature radius of the object-side surface and a curvature radius of the image-side surface of the third lens element are both either positive or negative.

28. The imaging lens system of claim 24, wherein the axial distance between the second lens element and the third lens element is T23, the axial distance between the third lens element and the fourth lens element is T34, the central thickness of the third lens element is CT3, the central thickness of the fourth lens element is CT4, the central thickness of the fifth lens element is CT5, and the following condition is satisfied:

1.15<

(T23+T34)/(CT3+CT4+CT5).

29. The imaging lens system of claim 24, wherein an Abbe number of the first lens element is V1, an Abbe number of the second lens element is V2, an Abbe number of the fourth lens element is V4, and the following condition is satisfied:

0.5<

(V2+V4)/V1<

1.0.

30. The imaging lens system of claim 24, wherein a maximum image height of the imaging lens system is ImgH, an entrance pupil diameter of the imaging lens system is EPD, and the following condition is satisfied:

0.85<

EPD/ImgH<

2.0.