Imaging lens

Patent metadata

Field	Value
Publication number	US-9494774-B2
Application number	US-201214355184-A
Country	US
Kind code	B2
Filing date	Oct 17, 2012
Priority date	Oct 31, 2011
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

The present invention relates to an imaging lens, the imaging lens including, in an ordered way from an object side, a first movable lens having a positive (+) refractive power, a second lens having a negative (−) refractive power, a third lens having a positive (+) refractive power, a fourth lens having a positive (+) refractive power, and a fifth lens having a negative (−) refractive power.

First claim

The invention claimed is:

1. An imaging lens, the imaging lens comprising, in an ordered way from an object side:
a first movable lens having a positive (+) refractive power;
a second lens having a negative (−) refractive power;
a third lens having a positive (+) refractive power;
a fourth lens having a positive (+) refractive power; and
a fifth lens having a negative (−) refractive power,
wherein the imaging lens meets a conditional expression of 0.8<f 3 /f 1 <1.0,
where f 1 and f 3 are focus distances (focal lengths) of the first and third lenses, respectively.

2. The imaging lens of claim 1 , wherein the second lens is concavely formed with a negative (−) refractive power.

3. The imaging lens of claim 1 , wherein the third lens has a meniscus shape convexly formed at an object side surface.

4. The imaging lens of claim 1 , wherein the fourth lens has a meniscus shape.

5. The imaging lens of claim 1 , wherein the third lens is formed at a front surface with all inflection points.

6. The imaging lens of claim 1 , wherein all surfaces of the third, fourth and fifth lenses are formed with one or more inflection points.

7. The imaging lens of claim 1 , wherein an aperture is positioned at a front end of an object side surface of the first lens.

8. The imaging lens of claim 1 , wherein the imaging lens meets a conditional expression of 0.5<f 1 /fz 1 <1.5, 0.5<f 1 /fz 2 <1.5, 0.5 <f 1 /fz 3 <1.5, where f 1 is an entire focus distance (focal length) of the first lens, and fz 1 , fz 2 and fz 3 are focus distances of zoom positions 1 , 2 and 3 , and where the zoom position 1 is an infinite position, the zoom position 2 is a 60 cm (middle) position and the zoom position 3 is a 10 cm (wide) position.

9. The imaging lens of claim 1 , wherein the imaging lens meets a conditional expression of 0.1<d 1 <0.4, 0.15<d 3 <0.54, where d 1 is an air clearance between L 1 center and L 2 center on a zoom position 1 , and d 2 is an air clearance between L 1 center and L 2 center on a zoom position 3 .

10. The imaging lens of claim 1 , wherein the imaging lens meets a conditional expression of 0.5<ΣT/fz 1 <1.5, 0.5<ΣT/fz 2 <1.5, 0.5<ΣT/fz 3 <1.5, where ΣT is a distance from an object side surface of the first lens to an image-forming surface, and fz 1 , fz 2 and fz 3 are focus distances of zoom positions 1 , 2 and 3 .

11. The imaging lens of claim 1 , wherein the imaging lens meets a conditional expression of 1.6<N 2 <1.7, 1.6<N 3 <1.7, 1.5<N 1 <1.6, 1.5<N 4 <1.6, 1.5<N 5 <1.6, where N 1 , N 2 , N 3 , N 4 and N 5 are refractive indexes of first, second, third, fourth and fifth lenses.

12. The imaging lens of claim 1 , wherein the imaging lens meets a conditional expression of 20<V 2 <30, 20<V 3 <30, 50<V 1 <60, 50<V 4 & V 5 <60, 50<V 5 <60, where V 1 , V 2 , V 3 , V 4 and V 5 are Abbe's numbers of the first, second, third, fourth and fifth lenses.

13. The imaging lens of claim 1 , wherein the imaging lens meets a conditional expression of 4.7<ΣT<5.9, where ΣT is a distance from an object side surface of the first lens to an image-forming surface.

14. The imaging lens of claim 1 , wherein the imaging lens meets a conditional expression of 2.0<F/#<3.0, where F/# is an F-number.

15. The imaging lens of claim 1 , wherein the imaging lens meets a conditional expression of L 3 R 1 >1, L 3 R 2 >1, where a radius of curvature of a first surface of the third lens is L 3 R 1 , and a radius of curvature of a second surface of the third lens is L 3 R 2 .

16. The imaging lens of claim 1 , wherein the imaging lens meets a conditional expressions of 0.8<|f 2 /fz 1 |<1.2, 0.8|f 2 /fz 2 |<1.2, 0.8<|f 2 /fz 3 |<1.2, 0.8<|f 3 /fz 1 |<3.7, 0.8<|f 3 /fz 2 |<3.7, 0.8<|f 3 /fz 3 |<3.7, 0.8<|f 4 /fz 1 |<1.0, 0.8<|f 4 /fz 2 |<1.0, 0.8<|f 4 /fz 3 |<1.0, 0.8<|f 5 /fz 1 |<0.8, 0.8<|f 5 /fz 2 |<0.8, 0.8<|f 5 /fz 3 |<0.8, where f 1 , f 2 , f 3 , f 4 and f 5 are focus distances of the first, second, third, fourth and fifth lenses, and fz 1 , fz 2 and fz 3 are focus distances of zoom positions 1 , 2 and 3 .

17. The imaging lens of claim 1 , wherein the imaging lens meets a conditional expression of 0.7<(r 3 +r 4 )/(r 3 −r 4 )<1.0, where r 3 and r 4 are respectively radius of curvature of an object side surface of the second lens and radius of curvature of an image side surface.

18. The imaging lens of claim 1 , wherein the imaging lens meets a conditional expression of 4.0<|(r 5 +r 6 )/(r 5 −r 6 )|<8.0, where r 5 and r 6 are respectively radius of curvature of an object side surface of the third lens and radius of curvature of an image side surface.

19. The imaging lens of claim 1 , wherein the imaging lens meets a conditional expression of 0.4<f 1 /ΣT<0.8, or 2.5<|f 3 /ΣT|<3.0, where ΣT is a distance from an object side surface of the first lens to an image-forming surface, and f 1 and f 3 are focus distances of first and third lenses.

20. An imaging lens, the imaging lens comprising, in an ordered way from an object side:
a first movable lens having a positive (+) refractive power;
a second lens having a negative (−) refractive power;
a third lens having a positive (+) refractive power;
a fourth lens having a positive (+) refractive power; and
a fifth lens having a negative (−) refractive power,
wherein the imaging lens meets a conditional expression of L 3 R 1 >1, L 3 R 2 >1, where a radius of curvature of a first surface of the third lens is L 3 R 1 , and a radius of curvature of a second surface of the third lens is L 3 R 2 .

21. A camera module, the camera module comprising an imaging lens comprising, in an ordered way from an object side:
a first movable lens having a positive (+) refractive power;
a second lens having a negative (−) refractive power;
a third lens having a positive (+) refractive power;
a fourth lens having a positive (+) refractive power; and
a fifth lens having a negative (−) refractive power,
wherein the imaging lens meets a conditional expression of 0.8<f 3 /f 1 <1.0, where f 1 and f 3 are focus distances (focal lengths) of the first and third lenses.

22. The camera module of claim 21 , wherein the imaging lens meets a conditional expression of L 3 R 1 >1, L 3 R 2 >1, where a radius of curvature of a first surface of the third lens is L 3 R 1 , and a radius of curvature of a second surface of the third lens is L 3 R 2 .

Assignees

• Lg Innotek Co Ltd

Inventors

• Lee Kyung Hwan

Classifications

• G02B13/009

  having zoom function · CPC title

• G02B13/0045

  having five or more lenses · CPC title

• G02B15/14 Primary

  by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective · CPC title

• G02B2003/0093

  characterised by the shape · CPC title

• G02B3/02

  with non-spherical faces (G02B3/10 takes precedence) · CPC title