LENS APPARATUS AND AN IMAGE PICKUP APPARATUS INCLUDING SAME

• US 20170351050A1
• Filed: 05/31/2017
• Published: 12/07/2017
• Est. Priority Date: 06/01/2016
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Sugita, Shigenobu, Nagao, Yuki, Inoue, Suguru
• Granted Patent: US 10,641,983 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 27/0025 for optical correction, e.g. distorsion, aberration
• CPC Class Codes: G02B 7/008 with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation
• CPC Class Codes: G02B 7/04 with mechanism for focusing or varying magnification
• CPC Class Codes: G02B 9/64 having more than six components

Abstract

A lens apparatus that includes an optical system including a positive lens, the lens apparatus including a holding member arranged to hold the positive lens, an exterior member arranged to accommodate the holding member, and an engaging mechanism arranged to engage the holding member and the exterior member to each other.

Claims

1. A lens apparatus that includes an optical system including a positive lens Gp, the lens apparatus comprising:

a holding member arranged to hold the positive lens Gp; and

an exterior member arranged to engage with the holding member and to accommodate the holding member,

wherein the temperature coefficient of a refractive index of the material of the positive lens Gp has a negative value, and

wherein assuming that a first plane is a plane that passes through a point on the object side surface of the positive lens Gp, positioned closest to an object, and that the first plane is perpendicular to the optical axis of the optical system, and a second plane is a plane that passes through a point on the image side surface of the positive lens Gp, positioned closest to an image, and that the second plane is perpendicular to the optical axis of the optical system, the holding member and the exterior member are disposed so as to be separated from each other with an air gap therebetween in a region between the first plane and the second plane.

3. The lens apparatus according to claim 1,

wherein a conditional expression

0.15<

fp/f<

0.60

is satisfied, where fp is a focal length of the positive lens Gp, and f is a focal length of the optical system.

4. The lens apparatus according to claim 1,

wherein a maximum width of the air gap between the holding member and the exterior member in the region between the first plane and the second plane is smaller than 0.2×

EDp, where EDp is an effective diameter of the lens surface of the positive lens Gp on the object side.

5. The lens apparatus according to claim 1,

wherein a negative lens Gn is disposed adjacent to the positive lens Gp.

6. The lens apparatus according to claim 5,

wherein the negative lens Gn is disposed adjacent to the image side of the positive lens Gp.

7. The lens apparatus according to claim 6,

wherein the temperature coefficient of refractive index of the material of the negative lens Gn has a positive value.

8. The lens apparatus according to claim 1,

the optical system includes at least one negative lens, and a temperature coefficient related to a refractive index of a material of the negative lens Gn disposed closest to the positive lens Gp has a positive value.

9. The lens apparatus according to claim 5,

wherein the negative lens Gn is held by the holding member, and

wherein assuming that a third plane is a plane that passes through a point on the object side surface of the negative lens Gn, positioned closest to an object, and that the third plane is perpendicular to the optical axis of the optical system, and a fourth plane is a plane that passes through a point on the image side surface of the negative lens Gn, positioned closest to an image, and that the fourth plane is perpendicular to the optical axis of the optical system, the holding member and the exterior member are disposed so as to be separated from each other with an air gap in between in a region between the third plane and the fourth plane.

10. The lens apparatus according to claim 9,

wherein a maximum width of the air gap between the holding member and the exterior member in the region between the first plane and the fourth plane is smaller than 0.2×

EDn, where EDn is an effective diameter of the lens surface of the negative lens Gn on the object side.

11. The lens apparatus according to claim 5,

wherein a conditional expression

0<

τ

n<

1.0×

10<sup>−

6</sup>

is satisfied, where τ

n is the temperature coefficient of the refractive index of the material of the negative lens Gn.

12. The lens apparatus according to claim 5,

wherein a conditional expression

20.0<

ν

dn<

45.0

is satisfied, where ν

dn is an Abbe constant of the material of the negative lens Gn.

13. The lens apparatus according to claim 5,

wherein a conditional expression

0.07<

−

fn/f<

0.30

is satisfied, where fn is a focal length of the negative lens Gn, and f is the focal length of the optical system.

14. The lens apparatus according to claim 5,

wherein a further positive lens Gp2 is disposed on the image side of the positive lens Gp, and the temperature coefficient of refractive index of a material of the further positive lens Gp2 is a negative value.

15. The lens apparatus according to claim 14,

wherein the holding member is arranged to hold the further positive lens Gp2, and

wherein assuming that a third plane is a plane that passes through a point on the object side surface of the negative lens Gn, positioned closest to an object, and that the third plane is perpendicular to the optical axis of the optical system, and a fourth plane is a plane that passes through a point on the image side surface of the negative lens Gn, positioned closest to an image, and that the fourth plane is perpendicular to the optical axis of the optical system, the holding member 6 and the exterior member 7 are disposed so as to be separated from each other with an air gap in between in a region between the third plane and the fourth plane.

16. The lens apparatus according to claim 15,

wherein a maximum width of the air gap between the holding member and the exterior member in the region between the first plane and the sixth plane is smaller than 0.2×

EDp2, where EDp2 is an effective diameter of the lens surface of the further positive lens Gp2 on the object side of the further positive lens Gp2.

17. The lens apparatus according to claim 1,

wherein the optical system includes a lens G1 disposed, among lenses included in the optical system, closest to the object.

18. The lens apparatus according to claim 17,

wherein a conditional expression

−

1.0×

10<sup>−

6</sup>τ

1<

1.0×

10<sup>−

6</sup>

is satisfied, where τ

1 is a temperature coefficient related to the refractive index of the material of the lens G1.

19. The lens apparatus according to claim 17,

wherein a conditional expression

0.30<

|f1/f|<

1.00

is satisfied, where f1 is a focal length of the lens G1, and f is the focal length of the optical system.

20. The lens apparatus according to claim 17,

wherein a conditional expression

0.17<

D1p/LD<

0.50

is satisfied, where D1p is a distance along the optical axis between the lens G1 and the positive lens Gp, and LD is a distance along the optical axis from a lens surface of the optical system that is closest to the object to the image plane.

21. The lens apparatus according to claim 17,

wherein the holding member and the exterior member are in contact with each other in a first contact region between the lens (G1) and the positive lens (Gp).

22. The lens apparatus according to claim 21,

wherein the holding member and the exterior member are in contact with each other in a second contact region on the image side with respect to the second plane.

23. The lens apparatus according to claim 22,

wherein a distance between the first contact region and the first plane in an optical axis direction is larger than a distance between the second contact region and the second plane in the optical axis direction.

2. A lens apparatus that includes an optical system including a positive lens Gp, the lens apparatus comprising:

a holding member arranged to hold the positive lens Gp; and

an exterior member arranged to engage with the holding member and to accommodate the holding member,

wherein a conditional expression

80.0<

ν

dp

is satisfied, where vdp is an Abbe constant of the material of the positive lens Gp, and

wherein assuming that a first plane is a plane that passes through a point on the object side surface of the positive lens Gp, positioned closest to an object, and that the first plane is perpendicular to the optical axis of the optical system, and a second plane is a plane that passes through a point on the image side surface of the positive lens Gp, positioned closest to an image, and that the second plane is perpendicular to the optical axis of the optical system, the holding member and the exterior member are disposed so as to be separated from each other with an air gap in between in a region between the first plane and the second plane.

24. An image pickup apparatus comprising:

a lens apparatus; and

an image pickup element,

wherein the lens apparatus includes

an optical system including a positive lens Gp,

a holding member arranged to hold the positive lens Gp, and

an exterior member arranged to engage with the holding member and to accommodate the holding member,

wherein the temperature coefficient of a refractive index of the material of the positive lens Gp has a negative value,

wherein assuming that a first plane is a plane that passes through a point on the object side surface of the positive lens Gp, positioned closest to an object, and that the first plane is perpendicular to the optical axis of the optical system, and a second plane is a plane that passes through a point on the image side surface of the positive lens Gp, positioned closest to an image, and that the second plane is perpendicular to the optical axis of the optical system, the holding member and the exterior member are disposed so as to be separated from each other with an air gap in between in a region between the first plane and the second plane.