Imaging lens and imaging apparatus equipped with the imaging lens

Patent metadata

Field	Value
Publication number	US-2016116715-A1
Application number	US-201514920896-A
Country	US
Kind code	A1
Filing date	Oct 23, 2015
Priority date	Oct 28, 2014
Publication date	Apr 28, 2016
Grant date	—

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 positive refractive power, a fourth lens having a positive refractive power, a fifth lens having a negative refractive power with a concave surface on the image side, and a sixth lens having a negative refractive power, in which predetermined conditional expressions are satisfied.

First claim

What is claimed is:

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 positive refractive power; a fourth lens having a positive refractive power; a fifth lens having a negative refractive power with a concave surface on the image side; and a sixth lens having a negative refractive power, wherein the following conditional expressions are satisfied:
0< f/f 1<1.22  (1)

0.68< f/f 2<0  (2)

0.15< f/L 6 f< 1.25  (3)

where:
f is the focal length of the entire system;
f 1 is the focal length of the first lens;
f 2 is the focal length of the second lens; and
L 6 f is the paraxial radius of curvature of the object side surface of the sixth lens.

2 . The imaging lens of claim 1 , wherein the sixth lens has a concave surface on the image side.

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

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

5 . The imaging lens of claim 1 , wherein the fifth lens has a biconcave shape.

6 . The imaging lens of claim 1 , wherein the third lens has a convex shape on the object side.

7 . The imaging lens of claim 1 , wherein the following conditional expression is further satisfied:
0.15< f/f 3<3  (4)

where f 3 is the focal length of the third lens.

8 . The imaging lens of claim 1 , wherein the following conditional expression is further satisfied:
0.65< f/f 4<3  (5)

where f 4 is the focal length of the fourth lens.

9 . The imaging lens of claim 1 , wherein the following conditional expression is further satisfied:
−3< f 6<−0.5  (6)

where f 6 is the focal length of the sixth lens.

10 . The imaging lens of claim 1 , wherein the following conditional expression is further satisfied:
0.5<( L 1 r+L 1 f )/( L 1 r−L 1 f )<3  (7)

where:
L 1 f is the paraxial radius of curvature of the object side surface of the first lens; and
L 1 r is the paraxial radius of curvature of the image side surface of the first lens.

11 . The imaging lens of claim 1 , wherein the following conditional expression is further satisfied:
−0.55<( L 5 r+L 5 f )/( L 5 r−L 5 f )<1  (8)

where:
L 5 f is the paraxial radius of curvature of the object side surface of the fifth lens; and
L 5 r is the paraxial radius of curvature of the image side surface of the fifth lens.

12 . The imaging lens of claim 1 , wherein the following conditional expression is further satisfied:
−7.5<( L 4 r+L 4 f )/( L 4 r−L 4 f )<0  (9)

where:
L 4 f is the paraxial radius of curvature of the object side surface of the fourth lens; and
L 4 r is the paraxial radius of curvature of the image side surface of the fourth lens.

13 . The imaging lens of claim 1 , wherein the following conditional expression is further satisfied:
−1.4< f·P 34<0  (10)

where P 34 is the refractive power of the air lens formed between the image side surface of the third lens and the object side surface of the fourth lens, and the refractive power of the air lens may be obtained by the following formula (P):

P



34

=

1
-

Nd



3

L



3

r

+

Nd



4

-
1

L



4

f

-

(

1
-

Nd



3

)

×

(

Nd



4

-
1

)

×
D



7

L



3

r
×
L



4

f

(
P
)

Assignees

• Fujifilm Corp

Inventors

• Ota Motoari

Classifications

• G02B9/62

  having six components only · CPC title

• G02B13/004

  having four lenses · CPC title

• G02B13/0045 Primary

  having five or more lenses · CPC title

• G02B27/0025

  for optical correction, e.g. distorsion, aberration · CPC title