Image capturing system

• US RE46,747 E1
• Filed: 08/02/2015
• Issued: 03/06/2018
• Est. Priority Date: 01/12/2012
• Status: Active Grant

• Current Assignee: Largan Precision Co Limited (Largan Precision)
• Original Assignee: Largan Precision Co Limited (Largan Precision)
• Inventors: Hsu, Po-Lun, Tsai, Tsung-Han, Chou, Ming-Ta
• Primary Examiner(s): Leung, Christina Y
• Application Number:
  US14/816,057
• Time in Patent Office: 947 Days
• Field of Search: 359764, 359766
• CPC Class Codes: G02B 13/0045 having five or more lenses

Abstract

An image capturing 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 a convex object-side surface. The second lens element has negative refractive power. The third lens element has positive refractive power. The fourth lens element with negative refractive power has a concave object-side surface and a convex image-side surface, wherein at least one of the object-side surface and the image-side surface of the fourth lens element is aspheric. The fifth lens element with refractive power has a concave image-side surface, wherein at least one of an object-side surface and the image-side surface of the fifth lens element is aspheric, and the fifth lens element has at least one inflection point on the image-side surface thereof.

Claims

1. An image capturing system comprising, 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 positive refractive power;

a fourth lens element with negative refractive power having a concave object-side surface and a convex image-side surface, wherein at least one of the object-side surface and the image-side surface of the fourth lens element is aspheric; and

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

wherein the first through fifth lens elements are five independent and non-cemented lens elements, a maximum image height of the image capturing system is ImgH, an axial distance between the object-side surface of the first lens element and an image plane is TTL, a focal length of the image capturing system is f, and the following relationship is satisfied;

2.8 mm<

(f/ImgH)×

TTL<

4.6 mm.

2. The image capturing system of claim 1, wherein the focal length of the image capturing system is f, a focal length of the second lens element is f2, and the following relationship is satisfied:

−

1.4<

f/f2<

−

0.18.

3. The image capturing system of claim 1, wherein 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, and the following relationship is satisfied:

0.20 mm<

(CT2+CT3+CT4)/3<

0.31 mm.

4. The image capturing 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, and the following relationship is satisfied:

20<

V1−

V2<

50.

5. The image capturing system of claim 1, wherein an Abbe number of the third lens element is V3, an Abbe number of the fourth lens element is V4, and the following relationship is satisfied:

27<

V3−

V4<

45.

6. The image capturing system of claim 1, wherein the axial distance between the object-side surface of the first lens element and an image plane is TTL, the focal length of the image capturing system is f, a half of the maximal field of view of the image capturing system is HFOV, and the following relationship is satisfied:

6.5 mm²<

TTL×

f/tan(HFOV)<

13.4 mm².

7. The image capturing system of claim 1, wherein at least one of the object-side surface and the image-side surface of the first through third lens elements respectively is aspheric, and the first through fifth lens elements are made of plastic material.

8. The image capturing system of claim 7, wherein a maximal field of view of the image capturing system is FOV, and the following relationship is satisfied:

70 degrees<

FOV<

90 degrees.

9. The image capturing system of claim 7, wherein the second lens element has a concave image-side surface.

10. The image capturing system of claim 7, wherein the fifth lens element has a convex object-side surface.

11. The image capturing system of claim 1, wherein the focal length of the image capturing system is f, and the following relationship is satisfied:

1.8 mm<

f<

3.2 mm.

12. An image capturing system comprising, 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 and a convex image-side surface, wherein at least one of the object-side surface and the image-side surface of the fourth lens element is aspheric; and

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

wherein an axial distance between the object-side surface of the first lens element and an image plane is TTL, a focal length of the image capturing system is f, a half of the maximal field of view of the image capturing system is HFOV, an Abbe number of the third lens element is V3, an Abbe number of the fourth lens element is V4, and the following relationships are satisfied;

6.0 mm²<

TTL×

f/tan(HFOV)<

16.0 mm²; and

27<

V3−

V4<

45.

13. The image capturing system of claim 12, wherein the second lens element has a concave image-side surface.

14. The image capturing system of claim 12, wherein 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, and the following relationship is satisfied:

0.2 mm<

(CT2+CT3+CT4)/3<

0.31 mm.

15. The image capturing system of claim 12, wherein an Abbe number of the first lens element is V1, an Abbe number of the second lens element is V2, and the following relationship is satisfied:

20<

V1−

V2<

50.

16. The image capturing system of claim 12, wherein the axial distance between the object-side surface of the first lens element and the image plane is TTL, the focal length of the image capturing system is f, the half of the maximal field of view of the image capturing system is HFOV, and the following relationship is satisfied:

6.5 mm²<

TTL×

f/tan(HFOV)<

13.4 mm².

17. The image capturing system of claim 12, wherein a maximal field of view of the image capturing system is FOV, and the following relationship is satisfied:

70 degrees<

FOV<

90 degrees.

18. The image capturing system of claim 12, wherein the focal length of the image capturing system is f, and the following relationship is satisfied:

1.8 mm<

f<

3.2 mm.

19. The image capturing system of claim 12, wherein at least one of the object-side surface and the image-side surface of the first through third lens elements respectively is aspheric, and the first through fifth lens elements are made of plastic material.

20. The image capturing system of claim 12, wherein a maximum image height of the image capturing system is ImgH, the axial distance between the object-side surface of the first lens element and the image plane is TTL, and the following relationship is satisfied:

TTL/ImgH<

1.55.

21. An image capturing system comprising, 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 and a convex image-side surface, wherein at least one of the object-side surface and the image-side surface of the fourth lens element is aspheric; and

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

wherein the first through fifth lens elements are five independent and non-cemented lens elements, an axial distance between the object-side surface of the first lens element and an image plane is TTL, and the following relationship is satisfied;

2.2 mm<

TTL<

3.5 mm.

22. The image capturing system of claim 21, wherein 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, and the following relationship is satisfied:

0.2 mm<

(CT2+CT3+CT4)/3<

0.31 mm.

23. The image capturing system of claim 21, wherein a maximum image height of the image capturing system is ImgH, the axial distance between the object-side surface of the first lens element and the image plane is TTL, and the following relationship is satisfied:

TTL/ImgH<

1.55.

24. The image capturing system of claim 21, wherein a maximal field of view of the image capturing system is FOV, and the following relationship is satisfied:

70 degrees<

FOV<

90 degrees.

25. The image capturing system of claim 21, wherein at least one of the object-side surface and the image-side surface of the first through third lens elements respectively is aspheric, and the first through fifth lens elements are made of plastic material.

26. The image capturing system of claim 21, wherein a focal length of the image capturing system is f, and the following relationship is satisfied:

1.8 mm<

f<

3.2 mm.

27. An image capturing system for imaging an object on an object side to an image plane on an image side opposite of the object side, comprising:

a first lens element structured to exhibit positive refractive power and to include a convex object-side surface and a concave image-side surface and positioned as an optical input of the image capturing system to receive light from the object to be imaged by the image capturing system onto the image plane;

a second lens element positioned next to the first lens element to receive light from the first lens element, the second lens element structured to exhibit negative refractive power and to include a convex object-side surface and a concave image-side surface;

a third lens element positioned next to the second lens element to receive light from the second lens element, and structured to exhibit positive refractive power and to include a convex image-side surface, the third lens element being thinner than the first lens element and thicker than the second lens element;

a fourth lens element positioned next to the third lens element to receive light from the third lens element, and structured to exhibit negative refractive power and to include a concave object-side surface and a convex image-side surface, the fourth lens element being thinner than the first lens element and thicker than the second lens element; and

a fifth lens element positioned next to the fourth lens element to receive light from the fourth lens element and to image onto the image plane, and structured to exhibit refractive power and to include an object-side surface that is convex on an optical axis of the fifth lens element and concave off the optical axis, and an image-side surface that is concave on the optical axis and convex off the optical axis, wherein the fifth lens element is shaped to include at least one inflection point is formed on each of the object-side and image-side surfaces and is thicker than the first lens element,

wherein the first, the second, the third, the fourth and the fifth lens elements are sequentially arranged from the object side toward the image side of the image capturing system.

28. The image capturing system of claim 27, wherein each of the first, the second, the third, the fourth and the fifth lens elements is a non-cemented lens element.

29. The image capturing system of claim 27, wherein the third lens element includes a concave object-side surface facing the second lens element.

30. The image capturing system of claim 27, wherein the second, the third and the fourth lens elements are structured to have central thickness values of CT2, CT3 and CT4, respectively, so that a total thickness of the three lens elements satisfies:

0.20 mm<

(CT2+CT3+CT4)/3<

0.31 mm.

31. The image capturing system of claim 27, wherein the third and the fourth lens elements are structured to have Abbe numbers of V3 and V4, respectively, to cause a difference of the Abbe numbers V3 and V4 to be between 27 and 45:

27<

V3−

V4<

45.

32. The image capturing system of claim 27, wherein the first, the second, the third, the fourth and the fifth lens elements are structured and arranged so that a ratio of an axial distance, TTL, between the object-side surface of the first lens element and the image plane of the image capturing system and a maximum image height, ImgH, of the image capturing system is less than 1.55:

TTL/ImgH<

1.55.

33. The image capturing system of claim 27, wherein the first, the second, the third, the fourth and the fifth lens elements are structured and arranged to effectuate a focal length, f, of the image capturing system between 1.8 mm and 3.2 mm:

1.8 mm<

f<

3.2 mm.

34. An image capturing system for imaging an object on an object side to an image plane on an image side opposite of the object side, comprising:

a first lens element structured to exhibit positive refractive power and to include a convex object-side surface facing the object side to direct light from the object into the image capturing system;

a second lens element positioned on an image side of the first lens element and structured to exhibit negative refractive power and to include a convex object-side surface facing the first lens element and a concave image-side surface;

a third lens element positioned on an image side of the second lens element and structured to exhibit positive refractive power and to include a convex image-side surface facing the fourth lens element, the third lens element being thinner than the first lens element;

a fourth lens element positioned on an image side of the third lens element and structured to exhibit negative refractive power and to include a concave object-side surface facing the third lens element and a convex image-side surface; and

a fifth lens element positioned on an image side of the fourth lens element and structured to exhibit refractive power and to project the image onto the image plane, the fifth lens element including an object-side surface that is convex on an optical axis of the fifth lens element and concave off the optical axis and an image-side surface that is concave on the optical axis and convex off the optical axis, wherein at least one inflection point is formed on each of the object-side and image-side surfaces of the fifth lens element,

wherein the first, the second, the third, the fourth and the fifth lens elements are structured and arranged to have a maximal field of view, FOV, of the image capturing system between 70 degrees and 90 degrees;

70 degrees<

FOV<

90 degrees.

35. The image capturing system of claim 34, wherein the first through fifth lens elements are each non-cemented lens elements.

36. The image capturing system of claim 34, wherein the first lens element has a concave image-side surface facing the image side of the second lens element.

37. The image capturing system of claim 34, wherein the third lens element has a concave object-side surface facing the image side of the second lens element.

38. The image capturing system of claim 34, wherein an Abbe number, V3, of the third lens element and an Abbe number, V4, of the fourth lens element have a difference between 27 and 45:

27<

V3−

V4<

45.

39. The image capturing system of claim 34, wherein a ratio of an axial distance, TTL, between the object-side surface of the first lens element and the image plane of the image capturing system and a maximum image height, ImgH, of the image capturing system is less than 1.55:

TTL/ImgH<

1.55.

40. The image capturing system of claim 34, wherein the first, the second, the third, the fourth and the fifth lens elements are structured and arranged to effectuate an axial distance, TTL, between the object-side surface of the first lens element and the image, a focal length, f, of the image capturing system, a half of the maximal field of view, HFOV, of the image capturing system to have a relation of:

6.0 mm²<

TTL×

f/tan(HFOV)<

16.0 mm².

41. An image capturing system, comprising:

a first lens having positive refractive power and being convex toward an object side;

a second lens having negative refractive power and being convex toward the object side and concave toward an image side;

a third lens having positive refractive power and being concave toward the object side and convex toward the image side;

a fourth lens having negative refractive power and being concave toward the object side and convex toward the image side; and

a fifth lens having a refractive power and comprising;

an object-side surface being convex in the center and concave at the periphery; and

an image-side surface being concave in the center and convex at the periphery, wherein;

at least one inflection point is formed on the object-side and image-side surfaces of the fifth lens,

the first lens is thicker than the third lens and the fourth lens is thicker than the second lens, and

the first lens, the second lens, the third lens, the fourth lens and the fifth lens are sequentially arranged from the object side toward the image side.

42. The image capturing system of claim 41, wherein the first lens is concave toward the image side.

43. The image capturing system of claim 41, wherein the second lens, the third lens, the fourth lens and the fifth lens are made of plastic.

44. The image capturing system of claim 43, wherein the first lens is made of plastic.

45. The image capturing system of claim 41, wherein the first and second lenses comprise at least one aspherical surface.

46. The image capturing system of claim 41, further comprising an aperture disposed in front of the first lens.

47. The image capturing system of claim 41, wherein

a focal length of the second lens is greater than a focal length of the fourth lens, and

a focal length of the third lens is greater than the focal length of the second lens.

48. The image capturing system of claim 47, wherein a focal length of the first lens is greater than the focal length of the second lens and shorter than the focal length of the third lens.

49. The image capturing system of claim 41, wherein

a radius of curvature of an object-side surface of the second lens is greater than a radius of curvature of an image-side surface of the second lens,

a radius of curvature of the object-side surface of the fifth lens is greater than a radius of curvature of the image-side surface of the fifth lens, and

a radius of curvature of an object-side surface of the fourth lens is greater than a radius of curvature of an image-side surface of the fourth lens.

50. The image capturing system of claim 49, wherein a radius of curvature of an image-side surface of the first lens is greater than a radius of curvature of an object-side surface of the first lens.

51. The image capturing system of claim 47, wherein the third lens is thicker than the second lens, and the first lens is thicker than the fourth lens.

52. The image capturing system of claim 51, wherein the fifth lens is thicker than the first lens.

53. An image capturing system, comprising:

a first lens having positive refractive power and being convex toward an object side and concave toward an image side;

a second lens having negative refractive power and being convex toward the object side and concave toward the image side;

a third lens having positive refractive power and being concave toward the object side and convex toward the image side;

a fourth lens having negative refractive power and being concave toward the object side and convex toward the image side; and

a fifth lens having refractive power and comprising;

an object-side surface being convex in the center and concave at the periphery; and

an image-side surface being concave in the center and convex at the periphery, wherein;

at least one inflection point is formed on the object-side and image-side surfaces of the fifth lens, and

the first lens, the second lens, the third lens, the fourth lens and the fifth lens are sequentially arranged from the object side toward the image side.

54. The image capturing system of claim 53, wherein the first lens, the second lens, the third lens, the fourth lens and the fifth lens are made of plastic.

55. The image capturing system of claim 53, wherein the first and second lenses comprise at least one aspherical surface.

56. The image capturing system of claim 53, further comprising an aperture disposed in front of the first lens.

57. The image capturing system of claim 53, wherein

a focal length of the second lens is greater than a focal length of the fourth lens,

a focal length of the first lens is greater than the focal length of the second lens, and

a focal length of the third lens is greater than the focal length of the first lens.

58. The image capturing system of claim 53, wherein

a radius of curvature of an image-side surface of the first lens is greater than a radius of curvature of an object-side surface of the first lens,

a radius of curvature of an object-side surface of the second lens is greater than a radius of curvature of an image-side surface of the second lens,

a radius of curvature of an object-side surface of the fourth lens is greater than a radius of curvature of an image-side surface of the fourth lens, and

a radius of curvature of the object-side surface of the fifth lens is greater than a radius of curvature of the image-side surface of the fifth lens.

59. The image capturing system of claim 53, wherein

the third and fourth lenses are thicker than the second lens,

the first lens is thicker than the third and fourth lenses, and

the fifth lens is thicker than the first lens.