IMAGING LENS

• US 20140313596A1
• Filed: 04/02/2014
• Published: 10/23/2014
• Est. Priority Date: 04/22/2013
• Status: Active Grant

• Current Assignee: Tokyo Visionary Optics Company Limited
• Original Assignee: Kantatsu Company Limited (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Hashimoto, Masaya
• Granted Patent: US 9,229,195 B2
• Time in Patent Office: Days
• US Class Current: 359/714
• CPC Class Codes: G02B 13/0045 having five or more lenses
• CPC Class Codes: G02B 13/06 Panoramic objectives; So-called "sky lenses" including panoramic objectives having reflecting surfaces

Abstract

A low-cost, compact and low-profile imaging lens with relatively high brightness, which provides a wide field of view (full field of view: about 90 degrees) and corrects aberrations properly. Designed for a solid-state image sensor, it includes elements arranged in the following order from an object side to an image side: an aperture stop, a first positive (refractive power) lens, a second negative lens having a concave image-side surface, a third positive lens having a convex image-side surface, a fourth lens as a meniscus double-sided aspheric lens having a convex object-side surface near an optical axis, a fifth negative lens as a double-sided aspheric lens having a concave image-side surface near the optical axis, and a conditional expression (1) below is satisfied:

|r1|>|r2|  (1)

• • where
  • r1: curvature radius of the object-side surface of the first lens
  • r2: curvature radius of the image-side surface of the first lens.

Claims

1. An imaging lens for a solid-state image sensor in which elements are arranged in order from an object side to an image side, comprising:

an aperture stop;

a first lens with positive refractive power;

a second lens with negative refractive power having a concave surface on the image side;

a third lens with positive refractive power having a convex surface on the image side;

a fourth lens as a meniscus double-sided aspheric lens having a convex surface on the object side near an optical axis; and

a fifth lens as a double-sided aspheric lens with negative refractive power having a concave surface on the image side near the optical axis,

wherein a conditional expression (1) below is satisfied;

|r1|>

|r2| 

 

(1)

where

r1;

curvature radius of the object-side surface of the first lens

r2;

curvature radius of the image-side surface of the first lens.

2. The imaging lens according to claim 1,

wherein a conditional expression (2) below is satisfied:

0.9<

ih/f<

1.1 

 

(2)

where

f;

focal length of an overall optical system of the imaging lens

ih;

maximum image height.

3. The imaging lens according to claim 1,

wherein a conditional expression (3) below is satisfied:

2.20<

|r1/r2|<

8.20 

 

(3)

where

r1;

curvature radius of the object-side surface of the first lens

r2;

curvature radius of the image-side surface of the first lens.

4. The imaging lens according to claim 1,

wherein a conditional expression (4) below is satisfied:

−

1.50<

f2/f<

−

1.00 

 

(4)

where

f;

focal length of an overall optical system of the imaging lens

f2;

focal length of the second lens.

5. The imaging lens according to claim 1,

wherein a conditional expression (5) below is satisfied:

0.70<

f3/f<

1.50 

 

(5)

where

f;

focal length of an overall optical system of the imaging lens

f3;

focal length of the third lens.

6. The imaging lens according to claim 1,

wherein the aspheric surfaces of the fourth lens have a pole-change point in a position off the optical axis.

7. The imaging lens according to claim 1,

wherein the aspheric surfaces of the fifth lens have a pole-change point in a position off the optical axis.

8. The imaging lens according to claim 1,

wherein a conditional expression (6) below is satisfied:

0.6<

TTL/2ih<

1.0 

 

(6)

where

TTL;

distance on the optical axis from the aperture stop to an image plane without a filter

ih;

maximum image height.

9. The imaging lens according to claim 2,

wherein a conditional expression (4) below is satisfied:

−

1.50<

f2/f<

−

1.00 

 

(4)

where

f2;

focal length of the second lens.

10. The imaging lens according to claim 2,

wherein a conditional expression (5) below is satisfied:

0.70<

f3/f<

1.50 

 

(5)

where

f3;

focal length of the third lens.

11. The imaging lens according to claim 2,

wherein the aspheric surfaces of the fourth lens have a pole-change point in a position off the optical axis.

12. The imaging lens according to claim 2,

wherein the aspheric surfaces of the fifth lens have a pole-change point in a position off the optical axis.

13. The imaging lens according to claim 2,

wherein a conditional expression (6) below is satisfied:

0.6<

TTL/2ih<

1.0 

 

(6)

where

TTL;

distance on the optical axis from the aperture stop to an image plane without a filter

ih;

maximum image height.