IMAGE PICKUP APPARATUS AND OPTICAL APPARATUS USING THE SAME

• US 20180224636A1
• Filed: 04/05/2018
• Published: 08/09/2018
• Est. Priority Date: 10/13/2015
• Status: Active Grant

• Current Assignee: Olympus Corporation
• Original Assignee: Olympus Corporation
• Inventors: Uchida, Yoshihiro, Takada, Keisuke
• Granted Patent: US 10,642,005 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 1/00096 Optical elements
• CPC Class Codes: A61B 1/041 Capsule endoscopes for imaging
• CPC Class Codes: B60R 11/04 Mounting of cameras operative during drive; Arrangement of controls thereof relative to the vehicle
• CPC Class Codes: B60R 2011/004 outside the vehicle
• CPC Class Codes: G02B 13/004 having four lenses
• CPC Class Codes: G02B 13/04 Reversed telephoto objectives
• CPC Class Codes: G02B 13/18 with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration G02B13/002 takes precedence
• CPC Class Codes: G02B 9/34 having four components only

Abstract

An image pickup apparatus includes an optical system which includes a plurality of lenses and an aperture stop, and an image sensor which is disposed at an image position of the optical system, wherein the optical system includes in order from an object side, a first lens having a negative refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, and a fourth lens, and the following conditional expressions (1) and (3) are satisfied:

αmax−αmin<4.0×10⁻⁵/° C.  (1), and

0.2<D1Ls/DsF<3.0  (3).

Claims

1. An image pickup apparatus, comprising:

an optical system which includes a plurality of lenses and an aperture stop; and

an image sensor which is disposed at an image position of the optical system, wherein

the optical system includes in order from an object side,

a first lens having a negative refractive power,

a second lens having a negative refractive power,

a third lens having a positive refractive power,

a fourth lens, and

an optical member through which light passes, on the object side of the optical system,

both surfaces of the optical member is curved surfaces, and

the following conditional expressions (1), (3), and (23) are satisfied;

α

max−

α

min<

4.0×

10<sup>−

5</sup>/°

C. 

 

(1),

0.2<

D1Ls/DsF<

3.0 

 

(3), and

30<

|Fc/FL| 

 

(23)

where,

α

max denotes a largest coefficient of linear expansion among coefficients of linear expansion at 20 degrees, of the plurality of lenses,

α

min denotes a smallest coefficient of linear expansion among the coefficients of linear expansion at 20 degrees, of the plurality of lenses,

D1Ls denotes a distance on an optical axis from an object-side surface of the first lens up to an object-side surface of the aperture stop,

DsF denotes a distance on the optical axis from an image-side surface of the aperture stop up to a lens surface positioned nearest to image.

Fc denotes a focal length of the optical member, and

FL denotes a focal length of the overall optical system.

2. The image pickup apparatus according to claim 1, wherein the following conditional expression (2) is satisfied:

0.1<

R1R/FL<

2.5 

 

(2),

where,

R1R denotes a paraxial radius of curvature of an image-side surface of the first lens,

FL denotes the focal length of the overall optical system.

3. The image pickup apparatus according to claim 1, wherein the following conditional expression (4) is satisfied:

−

0.01<

FL/R1L<

1.0 

 

(4),

where,

R1L denotes a paraxial radius of curvature of an object-side surface of the first lens, and

FL denotes the focal length of the overall optical system.

4. The image pickup apparatus according to claim 1, wherein the following conditional expression (5) is satisfied:

0.1<

R2R/FL<

50 

 

(5),

where,

R2R denotes a paraxial radius of curvature of an image-side surface of the second lens, and

FL denotes the focal length of the overall optical system.

5. The image pickup apparatus according to claim 1, wherein the following conditional expression (6) is satisfied:

−

1.0<

FL/R2L<

0.8 

 

(6),

where,

R2L denotes a paraxial radius of curvature of an object-side surface of the second lens, and

FL denotes the focal length of the overall optical system.

6. The image pickup apparatus according to claim 1, wherein the following conditional expression (7):

0.5<

Φ

1L/IH<

3.0 

 

(7),

where,

IH denotes α

maximum image height, and

Φ

1L denotes an effective aperture at the object-side surface of the first lens.

7. An image pickup apparatus according to claim 1, wherein

the optical system includes a lens surface positioned nearest to object and a lens surface positioned nearest to image, and

the following conditional expression (8) is satisfied:

0.05<

D1R2L/Σ

d<

0.5 

 

(8),

where,

D1R2L denotes an air space from the image-side surface of the first lens up to the object-side surface of the second lens, and

Σ

d denotes a distance from the lens surface positioned nearest to object up to the lens surface positioned nearest to image.

8. The image pickup apparatus according to claim 1, wherein

the optical system includes a lens surface positioned nearest to object and a lens surface positioned nearest to image, and

the following conditional expression (9) is satisfied:

0.01<

D2R3L/Σ

d<

0.3 

 

(9),

where,

D2R3L denotes an air space from the image-side surface of the second lens up to an object-side surface of the third lens, and

Σ

d denotes a distance from the lens surface positioned nearest to object up to the lens surface positioned nearest to image.

9. The image pickup apparatus according to claim 1, wherein

the optical system includes a lens surface positioned nearest to object and a lens surface positioned nearest to image, and

the following conditional expression (10) is satisfied:

0.05<

D3R4L/Σ

d<

0.5 

 

(10),

where,

D3R4L denotes an air space from an image-side surface of the third lens up to an object-side surface of the fourth lens, and

Σ

d denotes a distance from the lens surface positioned nearest to object up to the lens surface positioned nearest to image.

10. The image pickup apparatus according to claim 1, wherein the following conditional expression (11) is satisfied:

−

10.0<

f1/FL<

−

0.5 

 

(11),

where,

f1 denotes a focal length of the first lens, and

FL denotes the focal length of the overall optical system.

11. The image pickup apparatus according to claim 1, wherein the following conditional expression (12) is satisfied:

−

10.0<

f2/FL<

−

0.1 

 

(12),

where,

f2 denotes a focal length of the second lens, and

FL denotes the focal length of the overall optical system.

12. The image pickup apparatus according to claim 1, wherein the following conditional expression (13) is satisfied:

0.5<

f3/FL<

20.0 

 

(13),

where,

f3 denotes a focal length of the third lens, and

FL denotes the focal length of the overall optical system.

13. The image pickup apparatus according to claim 1, wherein

the optical system includes a lens surface positioned nearest to object and a lens surface positioned nearest to image,

the following conditional expression (14) is satisfied:

2.0<

Σ

d/FL<

8.0 

 

(14),

where,

Σ

d denotes a distance from the lens surface positioned nearest to object up to the lens surface positioned nearest to image, and

FL denotes a focal length of the overall optical system.

14. The image pickup apparatus according to claim 1, wherein the following conditional expression (15) is satisfied:

0.8<

ν

d1/ν

d3<

3.5 

 

(15),

where,

ν

d1 denotes Abbe number for the first lens, and

ν

d3 denotes Abbe number for the third lens.

15. The image pickup apparatus according to claim 1, wherein the following conditional expression (16) is satisfied:

0.8<

ν

d2/ν

d3<

3.5 

 

(16),

where,

ν

d2 denotes Abbe number for the second lens, and

ν

d3 denotes Abbe number for the third lens.

16. The image pickup apparatus according to claim 1, wherein the following conditional expression (17) is satisfied:

0.3<

ν

d3/ν

d4<

0.8 

 

(17),

where,

ν

d3 denotes Abbe number for the third lens, and

ν

d4 denotes Abbe number for the fourth lens.

17. The image pickup apparatus according to claim 1, wherein the following conditional expression (18) is satisfied:

−

1.0<

f1/R1L<

0 

 

(18),

where,

f1 denotes a focal length of the first lens, and

R1L denotes a paraxial radius of curvature of the object-side surface of the first lens.

18. The image pickup apparatus according to claim 1, wherein the following conditional expression (19) is satisfied:

−

1.0<

f2/R2L<

3.0 

 

(19),

where,

f2 denotes a focal length of the second lens, and

R2L denotes a paraxial radius of curvature of the object-side surface of the second lens.

19. The image pickup apparatus according to claim 1, wherein the following conditional expression (20) is satisfied:

−

1.0<

(R3L+R3R)/(R3L−

R3R)<

0.5 

 

(20),

where,

R3L denotes a paraxial radius of curvature of the object-side surface of the third lens, and

R3R denotes a paraxial radius of curvature of the image-side surface of the third lens.

20. The image pickup apparatus according to claim 1, wherein

the optical system includes a lens surface positioned nearest to object and a lens surface positioned nearest to image, and

the following conditional expression (21) is satisfied:

2.0<

Σ

d/Dmaxair<

9.0 

 

(21),

where,

Σ

d denotes a distance from the lens surface positioned nearest to object up to the lens surface positioned nearest to image, and

Dmaxair denotes a largest air space among air spaces between the lens surface positioned nearest to object and the lens surface positioned nearest to image.

21. An image pickup apparatus according to claim 1, wherein

the optical system includes an apertures stop, and

the following conditional expression (22) is satisfied:

1.0<

D1Ls/FL<

5.0 

 

(22),

where,

D1Ls denotes the distance on the optical axis from the object-side surface of the first lens up to an object-side surface of the apertures stop, and

FL denotes the focal length of the overall optical system.

22. The image pickup apparatus according to claim 1, wherein a half angle of view is not less than 65 degrees.

23. An optical apparatus, comprising:

an image pickup apparatus according to claim 1; and

a signal processing circuit.