IMAGING LENS AND IMAGING APPARATUS EQUIPPED WITH THE IMAGING LENS

• US 20160170182A1
• Filed: 12/10/2015
• Published: 06/16/2016
• Est. Priority Date: 12/16/2014
• Status: Active Grant

• Current Assignee: Jiangxi Ofilm Optical Company Limited
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: TANAKA, Takuya
• Granted Patent: US 9,715,086 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G02B 13/0045 having five or more lenses

Abstract

An imaging lens, consisting essentially of six lenses, composed of in order from the object side, a first lens having a positive refractive power with a convex surface on the object side, a second lens having a negative refractive power, a third lens having a convex surface on the object side, a fourth lens having a positive refractive power, a fifth lens having a negative refractive power, and a sixth lens having a negative refractive power, in which predetermined conditional expressions are satisfied.

Claims

1. An imaging lens, consisting of six lenses, composed of, in order from the object side:

a first lens having a positive refractive power with a convex surface on the object side;

a second lens having a negative refractive power;

a third lens having a convex surface on the object side;

a fourth lens having a positive refractive power;

a fifth lens having a negative refractive power; and

a sixth lens having a negative refractive power, wherein the following conditional expressions are satisfied;

1.55<

f/f1<

2.5 

 

(1)

−

1.65<

f/f2<

−

0.8 

 

(2)

0.5<

f/f4<

1.7 

 

(3)

where;

f is the focal length of the entire system;

f1 is the focal length of the first lens;

f2 is the focal length of the second lens; and

f4 is the focal length of the fourth lens.

2. The imaging lens of claim 1, wherein the second lens has a meniscus shape with a convex surface on the object side.

3. The imaging lens of claim 1, wherein the third lens has a meniscus shape with a convex surface on the object side.

4. The imaging lens of claim 1, wherein the fourth lens has a meniscus shape with a concave surface on the object side.

5. The imaging lens of claim 1, wherein the fifth lens has a concave surface on the object side.

6. The imaging lens of claim 1, further comprising an aperture stop located on the object side of the object side surface of the second lens.

7. The imaging lens of claim 1, wherein the following conditional expression is further satisfied:

−

1.5<

f/f6<

−

0.3 

 

(4)

where f6 is the focal length of the sixth lens.

8. The imaging lens of claim 1, wherein the following conditional expression is further satisfied:

−

5<

(L4r+L4f)/(L4r−

L4f)<

−

1.5 

 

(5)

where;

L4r is the paraxial radius of curvature of the image side surface of the fourth lens; and

L4f is the paraxial radius of curvature of the object side surface of the fourth lens.

9. The imaging lens of claim 1, wherein the following conditional expression is further satisfied:

1.6<

f/f1<

2.2 

 

(1-1).

10. The imaging lens of claim 9, wherein the following conditional expression is further satisfied:

1.65<

f/f1<

2 

 

(1-2).

11. The imaging lens of claim 1, wherein the following conditional expression is further satisfied:

−

1.6<

f/f2<

−

0.9 

 

(2-1).

12. The imaging lens of claim 11, wherein, the following conditional expression is further satisfied:

−

1.5<

f/f2<

−

1 

 

(2-2).

13. The imaging lens of claim 1, wherein the following conditional expression is further satisfied:

0.7<

f/f4<

1.6 

 

(3-1).

14. The imaging lens of claim 13, wherein the following conditional expression is further satisfied:

0.8<

f/f4<

1.5 

 

(3-2).

15. The imaging lens of claim 7, wherein the following conditional expression is further satisfied:

−

1.3<

f/f6<

−

0.4 

 

(4-1)

where f6 is the focal length of the sixth lens.

16. The imaging lens of claim 15, wherein the following conditional expression is further satisfied:

−

1.2<

f/f6<

−

0.5 

 

(4-2).

17. The imaging lens of claim 8, wherein the following conditional expression is further satisfied:

−

3.5<

(L4r+L4f)/(L4r−

L4f)<

−

1.6 

 

(5-1)

where;

L4r is the paraxial radius of curvature of the image side surface of the fourth lens; and

L4f is the paraxial radius of curvature of the object side surface of the fourth lens.

18. An imaging apparatus equipped with the imaging lens of claim 1.