IMAGING LENS

• US 20160306143A1
• Filed: 04/14/2016
• Published: 10/20/2016
• Est. Priority Date: 04/14/2015
• Status: Active Grant

• Current Assignee: Tokyo Visionary Optics Company Limited
• Original Assignee: Kantatsu Company Limited (Hon Hai Precision Industry Co., Ltd.)
• Inventors: HASHIMOTO, MASAYA, FUKAYA, HISAO
• Granted Patent: US 9,823,439 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G02B 13/0045 having five or more lenses
• CPC Class Codes: G02B 9/60 having five components only

Abstract

A compact high-resolution imaging lens which meets the demands for low-profileness, a low F-value and a wide field of view and corrects aberrations properly. It includes, in order from the object side: a first positive lens having a convex object-side surface; a second negative lens having a convex object-side surface; a third lens; a fourth positive lens; and a fifth negative double-sided aspheric lens having a concave image-side surface. When Fno denotes F-number, ih maximum image height, TTL total track length, f45 the composite focal length of the fourth and fifth lenses, r5 and r6 the curvature radii of the third lens object-side and image-side surfaces, r7 and r8 the curvature radii of the fourth lens object-side and image-side surfaces, and r9 and r10 the curvature radii of the fifth lens object-side and image-side surfaces, respectively, it satisfies the following conditions: Fno≦2.4; TTL/2ih<0.9; f45<0; 0<r5/r6<4.0; 0.5<(r7+r8)/(r7−r8)<3.0; and 0.4<(r9+r10)/(r9−r10)<4.0.

Claims

1. An imaging lens which forms an image of an object on a solid-state image sensor, comprising, in order from an object side to an image side:

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

a second lens with negative refractive power having a convex surface on the object side;

a third lens with positive or negative refractive power;

a fourth lens with positive refractive power; and

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

wherein conditional expressions (1) to (6) below are satisfied;

Fno≦

2.4 

 

(1)

TTL/2ih<

0.9 

 

(2)

f45<

0 

 

(3)

0<

r5/r6<

4.0 

 

(4)

0.5<

(r7+r8)/(r7−

r8)<

3.0 

 

(5)

0.4<

(r9+r10)/(r9−

r10)<

4.0 

 

(6)

where

Fno;

F-number

ih;

maximum image height

TTL;

total track length

f45;

composite focal length of the fourth lens and the fifth lens

r5;

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

r6;

curvature radius of the image-side surface of the third lens

r7;

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

r8;

curvature radius of the image-side surface of the fourth lens

r9;

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

r10;

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

2. The imaging lens according to claim 1,

wherein a conditional expression (7) below is satisfied:

3.0<

|f3/f| 

 

(7)

where

f;

focal length of an overall optical system of the imaging lens

f3;

focal length of the third lens.

3. The imaging lens according to claim 1,

wherein a conditional expression (8) below is satisfied:

0.4<

f4/f<

1.5 

 

(8)

where

f;

focal length of an overall optical system of the imaging lens

f4;

focal length of the fourth lens.

4. The imaging lens according to claim 1,

wherein a conditional expression (9) below is satisfied:

−

1.2<

f5/f<

−

0.2 

 

(9)

where

f;

focal length of an overall optical system of the imaging lens

f5;

focal length of the fifth lens.

5. The imaging lens according to claim 1,

wherein a conditional expression (10) below is satisfied:

0.08<

T3/TTL<

0.16 

 

(10)

where

T3;

distance on an optical axis between the image-side surface of the third lens and the object-side surface of the fourth lens.

TTL;

total track length.

6. The imaging lens according to claim 1,

wherein a conditional expression (11) below is satisfied:

0.5<

f1/f<

2.0 

 

(11)

where

f;

focal length of an overall optical system of the imaging lens

f1;

focal length of the first lens.

7. The imaging lens according to claim 1,

wherein a conditional expression (12) below is satisfied:

1.5<

r3/r4<

50 

 

(12)

where

r3;

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

r4;

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

8. The imaging lens according to claim 1, wherein the fourth lens has a convex surface on the image side.

9. The imaging lens according to claim 1, wherein the fifth lens has a pole point off an optical axis on the image-side surface.

10. The imaging lens according to claim 1, wherein a conditional expression (13) below is satisfied:

20<

ν

d1−

ν

d2<

40 

 

(13)

where

ν

d1;

Abbe number of the first lens at d-ray

ν

d2;

Abbe number of the second lens at d-ray.

11. The imaging lens according to claim 10, wherein a conditional expression (14) below is satisfied:

50<

ν

d3<

70 

 

(14)

where

ν

d3;

Abbe number of the third lens at d-ray.

12. The imaging lens according to claim 1, wherein a conditional expression (15) below is satisfied:

0.70<

ih/f<

1.0 

 

(15)

where

f;

focal length of an overall optical system of the imaging lens

ih;

maximum image height.