CORRECTION LENS AND IMAGING APPARATUS

• US 20200132970A1
• Filed: 10/28/2019
• Published: 04/30/2020
• Est. Priority Date: 10/31/2018
• Status: Active Grant

• Current Assignee: Tamron Company Limited
• Original Assignee: Tamron Company Limited
• Inventors: FUSE, Shingo
• Granted Patent: US 11,194,129 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 13/0045 having five or more lenses
• CPC Class Codes: G02B 13/08 Anamorphotic objectives
• CPC Class Codes: G02B 27/0025 for optical correction, e.g. distorsion, aberration
• CPC Class Codes: G02B 3/06 with cylindrical or toric faces
• CPC Class Codes: G02B 9/64 having more than six components

Abstract

A correction lens is used in an optical system in which a light-transmissive cover member having radii of curvature different from each other in a predetermined first direction and a second direction perpendicular to the first direction is disposed on an object side. Radii of curvature of an image-side surface of the correction lens are different in the first direction and the second direction, and satisfy a predetermined condition.

Claims

1. A correction lens used in an optical system in which a light-transmissive cover member having radii of curvature different from each other in a first direction perpendicular to an optical axis and a second direction perpendicular to the optical axis and the first direction is disposed on an object side,

wherein radii of curvature of an image-side surface of the correction lens are different in the first direction and the second direction, and

the following condition is satisfied:

0.0≤

|R2S/R2L|<

1.0 

 

(1)

where

R2S is a radius of curvature of the image-side surface of the correction lens in the first direction or the second direction and has a smaller absolute value, and

R2L is a radius of curvature of the image-side surface of the correction lens in the first direction or the second direction and has a larger absolute value.

2. The correction lens according to claim 1,

wherein a refractive power of the light-transmissive cover member and a refractive power of the correction lens have different signs in at least any one direction of the first direction and the second direction.

3. The correction lens according to claim 1,

wherein, when the light-transmissive cover member has a refractive power in any one direction of the first direction and the second direction, the correction lens has a refractive power having the same sign as the light-transmissive cover member in the other direction.

4. The correction lens according to claim 1,

wherein the following conditions are satisfied:

0≤

(|RAx|−

|RBx|)/(|RAx|+|RBx|)<

0.27, and 

 

(2)

0≤

(|RAy|−

|RBy|)/(|RAy|+|RBy|)<

0.27 

 

(3)

where

RAx is a radius of curvature of an object-side surface or an image-side surface of the correction lens in the first direction and has a larger absolute value,

RBx is a radius of curvature of the object-side surface or the image-side surface of the correction lens in the first direction and has a smaller absolute value,

RAy is a radius of curvature of the object-side surface or the image-side surface of the correction lens in the second direction and has a larger absolute value, and

RBy is a radius of curvature of the object-side surface or the image-side surface of the correction lens in the second direction and has a smaller absolute value.

5. The correction lens according to claim 1,

wherein a glass material of the correction lens is the same as a glass material of the light-transmissive cover member.

7. An imaging apparatus comprising:

the correction lens according to claim 1;

the optical system; and

an image sensor that is disposed closer to an image side than the optical system, and on which an optical image formed by the optical system and the correction lens is incident.

6. A correction lens which is used in an optical system in which a light-transmissive cover member having radius of curvature different from each other in a first direction perpendicular to an optical axis and a second direction perpendicular to the optical axis and the first direction is disposed on an object side and corrects a shift between focal positions caused in the first direction and the second direction by the light-transmissive cover member,

wherein radii of curvature of an image-side surface of the correction lens are different in the first direction and the second direction, and each radius of curvature is set to a different value depending on the radius of curvature of the light-transmissive cover member in each direction.