Imaging lens

• US 9,448,387 B2
• Filed: 01/30/2015
• Issued: 09/20/2016
• Est. Priority Date: 07/02/2014
• Status: Active Grant

• Current Assignee: Tokyo Visionary Optics Company Limited
• Original Assignee: Kantatsu Company Limited (Hon Hai Precision Industry Co., Ltd.), Optical Logic Inc.
• Inventors: Kubota, Yoji, Kubota, Kenichi, Hirano, Hitoshi, Fukaya, Hisao
• Primary Examiner(s): HASAN, MOHAMMED A
• Application Number:
  US14/609,469
• Publication Number:
  US 20160004044A1
• Time in Patent Office: 599 Days
• Field of Search: 359694-713, 359811-830, 359/691
• US Class Current: 1/1
• CPC Class Codes: G02B 13/0045 having five or more lenses
• CPC Class Codes: G02B 27/0025 for optical correction, e.g. distorsion, aberration
• CPC Class Codes: G02B 5/005 Diaphragms for cameras G03B9/02
• CPC Class Codes: G02B 9/62 having six components only

Abstract

An imaging lens includes a first lens group having positive refractive power and a second lens group having negative refractive power, arranged in this order from an object side to an image plane side. The first lens group includes a first lens having positive refractive power, a second lens having positive refractive power, and a third lens having negative refractive power. The second lens group includes a fourth lens having positive refractive power, a fifth lens, and a sixth lens having negative refractive power. The first lens and second lens have specific focal lengths. The first to third lenses have specific Abbe'"'"'s numbers.

Claims

1. An imaging lens comprising:

a first lens group having positive refractive power; and

a second lens group having negative refractive power, arranged in this order from an object side to an image plane side,

wherein said first lens group includes a first lens having positive refractive power, a second lens having positive refractive power, and a third lens having negative refractive power,

said second lens group includes a fourth lens having positive refractive power, a fifth lens having negative refractive power, and a sixth lens having negative refractive power, and

said first lens has a focal length f1, said second lens has a focal length f2, said fourth lens has a focal length f4, said fifth lens has a focal length f5, said first lens has an Abbe'"'"'s number ν

d1, said second lens has an Abbe'"'"'s number ν

d2, and said third lens has an Abbe'"'"'s number ν

d3 so that the following conditional expressions are satisfied;

0.3<

f1/f2<

0.9,

40<

ν

d1<

75,

40<

ν

d2<

75,

15<

ν

d3<

35,

−

15<

f5/f4<

−

5.

2. The imaging lens according to claim 1, wherein said second lens has the focal length f2 so that the following conditional expression is satisfied:

1.0<

f2/f<

2.0,

where f is a focal length of a whole lens system.

3. The imaging lens according to claim 1, wherein said first lens group has a focal length F1, and said second lens group has a focal length F2 so that the following conditional expression is satisfied:

−

12<

F2/F1<

−

1.5.

4. The imaging lens according to claim 1, wherein said third lens is arranged away from the fourth lens by a distance D34 on an optical axis so that the following conditional expression is satisfied:

0.05<

D34/f<

0.35,

where f is a focal length of a whole lens system.

5. The imaging lens according to claim 1, wherein said fifth lens and said sixth lens have a composite focal length f56 so that the following conditional expression is satisfied:

−

3<

f56/f<

−

0.8,

where f is a focal length of a whole lens system.

6. An imaging lens comprising:

a first lens group having positive refractive power; and

a second lens group having negative refractive power, arranged in this order from an object side to an image plane side,

wherein said first lens group includes a first lens having positive refractive power, a second lens having positive refractive power, and a third lens having negative refractive power,

said second lens group includes a fourth lens having positive refractive power, a fifth lens, and a sixth lens having negative refractive power, and

said first lens has a focal length f1, said second lens has a focal length f2, said fifth lens and said sixth lens have a composite focal length f56, said first lens has an Abbe'"'"'s number ν

d1, said second lens has an Abbe'"'"'s number ν

d2, and said third lens has an Abbe'"'"'s number ν

d3 so that the following conditional expressions are satisfied;

0.3<

f1/f2<

0.9,

40<

ν

d1<

75,

40<

ν

d2<

75,

15<

ν

d3<

35,

−

3<

f56/f<

−

0.8,

where f is a focal length of a whole lens system.

7. The imaging lens according to claim 6, wherein said second lens has the focal length f2 so that the following conditional expression is satisfied:

1.0<

f2/f<

2.0.

8. The imaging lens according to claim 6, wherein said first lens group has a focal length F1, and said second lens group has a focal length F2 so that the following conditional expression is satisfied:

−

12<

F2/F1<

−

1.5.

9. The imaging lens according to claim 6, wherein said third lens is arranged away from the fourth lens by a distance D34 on an optical axis so that the following conditional expression is satisfied:

0.05<

D34/f<

0.35.

10. An imaging lens comprising:

a first lens group having positive refractive power; and

a second lens group having negative refractive power, arranged in this order from an object side to an image plane side,

wherein said first lens group includes a first lens having positive refractive power, a second lens having positive refractive power, and a third lens having negative refractive power, arranged in this order from the object side to the image plane side,

said second lens group includes a fourth lens having positive refractive power, a fifth lens, and a sixth lens having negative refractive power, and

said first lens has a focal length f1, said second lens has a focal length f2, said first lens has an Abbe'"'"'s number ν

d1, said second lens has an Abbe'"'"'s number ν

d2, and said third lens has an Abbe'"'"'s number ν

d3 so that the following conditional expressions are satisfied;

0.3<

f1/f2<

0.9,

40<

ν

d1<

75,

40<

ν

d2<

75,

15<

ν

d3<

35.

11. The imaging lens according to claim 10, wherein said second lens has the focal length f2 so that the following conditional expression is satisfied:

1.0<

f2/f<

2.0,

where f is a focal length of a whole lens system.

12. The imaging lens according to claim 10, wherein said first lens group has a focal length F1, and said second lens group has a focal length F2 so that the following conditional expression is satisfied:

−

12<

F2/F1<

−

1.5.

13. The imaging lens according to claim 10, wherein said third lens is arranged away from the fourth lens by a distance D34 on an optical axis so that the following conditional expression is satisfied:

0.05<

D34/f<

0.35,

where f is a focal length of a whole lens system.

14. The imaging lens according to claim 10, wherein said fifth lens has negative refractive power, said fourth lens has a focal length f4, and said fifth lens has a focal length f5 so that the following conditional expression is satisfied:

−

15<

f5/f4<

−

5.

15. The imaging lens according to claim 10, wherein said fifth lens and said sixth lens have a composite focal length f56 so that the following conditional expression is satisfied:

−

3<

f56/f<

−

0.8,

where f is a focal length of a whole lens system.