Image pickup apparatus

Patent metadata

Field	Value
Publication number	US-9921409-B2
Application number	US-201615090788-A
Country	US
Kind code	B2
Filing date	Apr 5, 2016
Priority date	Apr 7, 2015
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

Provided is an image pickup apparatus, including: an image pickup optical system including a protection lens, which is arranged closest to a light incident side and has a convex-shaped surface on light incident side; and a housing houses the image pickup optical system, in which the image pickup optical system includes an aperture stop, and an optical systems A and B, which are arranged on an image side of aperture stop to be selectively placed in an optical path of image pickup optical system, the optical systems A and B having mutually different optical characteristics, and in which the housing separates a medium outside of housing and an inside of housing, and in which the image pickup apparatus further includes a switching unit selectively places one of optical systems A and B in optical path of image pickup optical system depending on a medium outside housing.

First claim

What is claimed is:

1. An image pickup apparatus, comprising: an image pickup optical system including a protection lens arranged closest to a light incident side and having a convex-shaped surface on the light incident side an aperture stop, an optical system A, and an optical system B having different optical characteristics from the optical system A;
a housing configured to house the image pickup optical system and separate a medium outside the housing and a medium inside the housing; and
a switching unit arranged in the housing, connected to the optical system A and the optical system B, and configured to place the optical system A in an optical path of the image pickup optical system and the optical system B out of the optical path when the medium outside the housing is a first medium, and to place the optical system A out of the optical path and the optical system B in the optical path when the medium outside the housing is a second medium different from the first medium.

2. The image pickup apparatus according to claim 1 , wherein the protection lens is fixed and held by the housing.

3. The image pickup apparatus according to claim 1 , wherein each of the optical system A and the optical system B consists of at most two lenses.

4. The image pickup apparatus according to claim 1 , wherein the following conditional expression is satisfied:
0.04<( fA−fB )× G 1 R 1/( fA×fB )<1.80,

where fA represents a focal length of the optical system A, fB represents a focal length of the optical system B, and G 1 R 1 represents a curvature radius of a lens surface on the light incident side of the protection lens.

5. The image pickup apparatus according to claim 1 , wherein the following conditional expression is satisfied:
0.50< G 1 R 1/ L< 3.00,
where G 1 R 1 represents a curvature radius of a lens surface on the light incident side of the protection lens, and L represents a total lens length of the image pickup optical system.

6. The image pickup apparatus according to claim 1 , wherein the following conditional expressions are satisfied:
0.02< KA/L< 0.60; and
0.02< KB/L< 0.60,
where KA represents a distance from a vertex of a lens surface closest to the light incident side of the optical system A to an image plane when the optical system A is placed in the optical path of the image pickup optical system, KB represents a distance from a vertex of a lens surface closest to the light incident side of the optical system B to the image plane when the optical system B is placed in the optical path of the image pickup optical system, and L represents a total lens length of the image pickup optical system.

7. The image pickup apparatus according to claim 1 ,
wherein the optical system B includes at least one positive lens, and
wherein the following conditional expression is satisfied:
10.0<ν dB< 62.0,

where νdB represents an Abbe number of a material of a positive lens Bp having a highest refractive power in the optical system B.

8. The image pickup apparatus according to claim 1 , wherein the following conditional expression is satisfied:
0.80< fWB/fWA< 1.02,
where fWA represents a focal length of an entire system of the image pickup optical system when the optical system A is placed in the optical path of the image pickup optical system, and fWB represents a focal length of the entire system when the optical system B is placed in the optical path of the image pickup optical system.

9. The image pickup apparatus according to claim 7 , wherein the second medium satisfies the following conditional expression:
1.10< nd< 1.50,
where nd represents a refractive index of the second medium with respect to a d-line.

10. The image pickup apparatus according to claim 1 ,
wherein the optical system A includes at least one positive lens, and the optical system B includes at least one positive lens, and
wherein the following conditional expression is satisfied:
1.00<ν dA/νdB< 5.00,

where νdA represents an Abbe number of a material of a positive lens Ap having a highest refractive power of the at least one positive lens included in the optical system A, and νdB represents an Abbe number of a material of a positive lens Bp having a highest refractive power of the at least one positive lens included in the optical system B.

11. The image pickup apparatus according to claim 1 ,
wherein the optical system A includes at least one positive lens, and the optical system B includes at least one positive lens, and
wherein the following conditional expression is satisfied:
1.00≦ ndGB/ndGA< 1.60,

where ndGA represents a refractive index with respect to a d-line of a material of a positive lens Ap having a highest refractive power of the at least one positive lens included in the optical system A, and ndGB represents a refractive index with respect to the d-line of a material of a positive lens Bp having a highest refractive power of the at least one positive lens included in the optical system B.

12. An image pickup apparatus, comprising: an image pickup optical system including a protection lens, arranged closest to a light incident side and having a convex-shaped surface on the light incident side an aperture stop, and an optical system C; a housing configured to house the image pickup optical system and separate a medium outside the housing and a medium inside the housing; and an insertion/removal unit arranged in the housing directly connected to the optical system C, and configured to insert or remove the optical system C into or from an optical path of the image pickup optical system on an image side of the aperture stop depending on the medium outside the housing, wherein the following conditional expression is satisfied: 0.04<(1/fC)×G 1 R 1 <1.80, where C represents a focal length of the optical system C, and G 1 R 1 represents a curvature radius of a lens surface on the light incident side of the protection lens.

13. The image pickup apparatus according to claim 12 , wherein the protection lens is fixed and held by the housing.

14. The image pickup apparatus according to claim 12 , wherein the optical system C consists of at most two lenses.

15. The image pickup apparatus according to claim 12 , wherein the following conditional expression is satisfied:
0.50< G 1 R 1/ L< 3.00,
where G 1 R 1 represents a curvature radius of a lens surface on the light incident side of the protection lens, and L represents a total lens length of the image pickup optical system.

16. The image pickup apparatus according to claim 12 , wherein the following conditional expression is satisfied:
0.02< KC/L< 0.60,
where KC represents a distance from a vertex of a lens surface closest to the light incident side of the optical system C to an image plane when the optical system C is placed in the optical path of the image pickup optical system, and L represents a total lens length of the image pickup optical system.

17. The image pickup apparatus according to claim 12 ,
wherein the optical system C includes at least one positive lens, and
wherein the following conditional expression is satisfied:
10.0<ν dC< 62.0,

where νdC represents an Abbe number of a material of a positive lens Cp having a highest refractive power in the optical system C.

18. The image pickup apparatus according to claim 12 , wherein the following conditional expression is satisfied:
0.80< fWC 1/ fWC 2<1.02,
where fWC 1 represents a focal length of an entire system of the image pickup optical system when the optical system C is plac

Assignees

• Canon Kk

Inventors

• Aoki Koji

Classifications

• H04N23/51

  Housings · CPC title

• G03B5/00

  Adjustment of optical system relative to image or object surface other than for focusing · CPC title

• G02B27/0068 Primary

  having means for controlling the degree of correction, e.g. using phase modulators, movable elements (controlling the phase of light using moving or deformable elements G02B26/06) · CPC title

• G03B17/14

  interchangeably · CPC title

• G02B15/142

  having two groups only · CPC title