Image pickup apparatus

Patent metadata

Field	Value
Publication number	US-2016299338-A1
Application number	US-201615090788-A
Country	US
Kind code	A1
Filing date	Apr 5, 2016
Priority date	Apr 7, 2015
Publication date	Oct 13, 2016
Grant date	—

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, which is arranged closest to a light incident side and has a convex-shaped surface on the light incident side; and a housing configured to house the image pickup optical system, wherein the image pickup optical system includes an aperture stop, and an optical system A and an optical system B, which are arranged on an image side of the aperture stop to be selectively placed in an optical path of the image pickup optical system, the optical system A and the optical system B having mutually different optical characteristics, wherein the housing is configured to separate a medium outside the housing and an inside of the housing, and wherein the image pickup apparatus further comprises a switching unit configured to selectively place one of the optical system A and the optical system B in the optical path of the image pickup optical system depending on the medium outside the housing.

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

3 . An 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 . An 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 . An 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 . An 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 . An 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 . An 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 . An image pickup apparatus according to claim 1 , wherein, when the medium outside the housing is a medium that satisfies the following conditional expression:
1.10< nd< 1.50, where nd represents a refractive index of the medium outside the housing with respect to a d-line, the switching unit is configured to place the optical system B in the optical path of the image pickup optical system.

10 . An 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 . An 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, which is arranged closest to a light incident side and has a convex-shaped surface on the light incident side; and a housing configured to house the image pickup optical system, wherein the image pickup optical system includes an aperture stop, and an optical system C, which is arranged on an image side of the aperture stop to be removably insertable into an optical path of the image pickup optical system, wherein the housing is configured to separate a medium outside the housing and a medium inside the housing, and wherein the image pickup apparatus further comprises an insertion/removal unit configured to insert or remove the optical system C into or from the optical path of the image pickup optical system depending on the medium outside the housing.

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

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

15 . An image pickup apparatus according to claim 12 , wherein the following conditional expression is satisfied:
0.04<(1/ fC )× G 1 R 1<1.80,
where fC 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.

16 . An 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.

17 . An 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.

18 . An image pickup apparatus according to claim 12 ,
wherein the optical system C includes at least one positive lens, and wherein the following co

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