IMAGING LENS

• US 20150070783A1
• Filed: 03/27/2014
• Published: 03/12/2015
• Est. Priority Date: 09/11/2013
• 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 9,507,125 B2
• Time in Patent Office: Days
• US Class Current: 359/708
• 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 9/64 having more than six components
• CPC Class Codes: G06T 5/70 Denoising; Smoothing
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336

Abstract

An imaging lens which uses a larger number of constituent lenses for higher performance and features compactness and a wide field of view. The imaging lens is composed of seven lenses to form an image of an object on a solid-state image sensor. The constituent lenses are arranged in the following order from an object side to an image side: a first lens with positive refractive power; a second lens with positive or negative refractive power; a third lens with negative refractive power; a fourth lens with positive or negative refractive power as a double-sided aspheric lens; a meniscus fifth lens having a convex surface on the image side; a sixth lens with positive or negative refractive power as a double-sided aspheric lens; and a seventh lens with negative refractive power, in which an air gap is provided between lenses.

Claims

1. An imaging lens composed of seven lenses to form an image of an object on a solid-state image sensor, in which the lenses are arranged in order from an object side to an image side, comprising:

a first lens with positive refractive power;

a second lens with positive or negative refractive power;

a third lens with negative refractive power;

a fourth lens with positive or negative refractive power as a double-sided aspheric lens;

a meniscus fifth lens having a convex surface on the image side;

a sixth lens with positive or negative refractive power as a double-sided aspheric lens; and

a seventh lens with negative refractive power,

wherein an air gap is provided between lenses.

2. The imaging lens according to claim 1,

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

the second lens is a lens with positive or negative refractive power having a convex surface on the image side; and

at least one of facing surfaces of the first lens and the second lens is a concave surface.

3. The imaging lens according to claim 1,

wherein a conditional expression (1) below is satisfied:

0<

f12 

 

(1)

where

f12;

composite focal length of the first lens and the second lens.

4. The imaging lens according to claim 1,

wherein the third lens is a double-sided aspheric lens and has a concave surface on the image side near an optical axis.

5. The imaging lens according to claim 1,

wherein the fourth lens is a biconvex lens having a convex surface on the object side near an optical axis or a meniscus lens having a convex surface on the object side.

6. The imaging lens according to claim 1,

wherein an image-side surface of the sixth lens has an aspheric shape in which a portion near an optical axis has a concave shape and the concave shape changes to a convex shape in a peripheral portion distant from the optical axis.

7. The imaging lens according to claim 1,

wherein a conditional expression (2) below is satisfied:

0.6<

f12/f<

1.3 

 

(2)

where

f12;

composite focal length of the first lens and the second lens

f;

focal length of the overall optical system of the imaging lens.

8. The imaging lens according to claim 1,

wherein a conditional expression (3) below is satisfied:

−

2.2<

f3/f<

−

1.0 

 

(3)

where

f3;

focal length of the third lens

f;

focal length of the overall optical system of the imaging lens.

9. The imaging lens according to claim 1,

wherein a conditional expression (4) below is satisfied:

0.6<

f45/f<

2.2 

 

(4)

where

f45;

composite focal length of the fourth lens and the fifth lens

f;

focal length of the overall optical system of the imaging lens.

10. The imaging lens according to claim 1,

wherein a conditional expression (5) below is satisfied:

−

2.0<

f67/f<

−

0.6 

 

(5)

where

f67;

composite focal length of the sixth lens and the seventh lens

f;

focal length of the overall optical system of the imaging lens.

11. The imaging lens according to claim 1,

wherein conditional expressions (6) to (8) below are satisfied:

50<

ν

d1<

70 

 

(6)

50<

ν

d2<

70 

 

(7)

20<

ν

d3<

30 

 

(8)

where

ν

d1;

Abbe number of the first lens at d-ray

ν

d2;

Abbe number of the second lens at d-ray

ν

d3;

Abbe number of the third lens at d-ray.