阅读说明：本技术 镜头系统、相机系统以及摄像系统 (Lens system, camera system, and imaging system ) 是由 松村善夫 于 2018-02-13 设计创作，主要内容包括：本公开提供一种镜头系统、相机系统以及摄像系统,所述镜头系统是在配置于光轴的矩形的摄像元件进行成像的镜头系统,具备相对于光轴不对称的第1自由曲面透镜。在与光轴相距相对于最短像高的给定比率的长度的圆、和穿过光轴且与摄像元件的长边平行的第1面的交点,第1自由曲面透镜的自由曲面针对与光轴平行的光线具有负的屈光力,在与光轴相距相对于最短像高的给定比率的长度的圆、和穿过光轴且与摄像元件的短边平行的第2面的交点,第1自由曲面透镜的自由曲面针对与光轴平行的光线具有正的屈光力。(The present disclosure provides a lens system for forming an image on a rectangular image pickup element disposed on an optical axis, the lens system including a 1 st free-form surface lens asymmetric with respect to the optical axis, a camera system, and an image pickup system. The free-form surface of the 1 st free-form surface lens has a negative refractive power with respect to a light ray parallel to the optical axis at an intersection of a circle having a length at a given ratio to the shortest image height from the optical axis and a 1 st surface passing through the optical axis and parallel to the long side of the image pickup element, and the free-form surface of the 1 st free-form surface lens has a positive refractive power with respect to a light ray parallel to the optical axis at an intersection of a circle having a length at a given ratio to the shortest image height from the optical axis and a 2 nd surface passing through the optical axis and parallel to the short side of the image pickup element.)

1. A lens system for forming an image on a rectangular image pickup element disposed on an optical axis,

the lens system is provided with a 1 st free-form surface lens asymmetrical with respect to the optical axis,

a free-form surface of the 1 st free-form surface lens has a negative refractive power with respect to a light ray parallel to the optical axis at an intersection of a circle having a length at a given ratio with respect to a shortest image height from the optical axis and a 1 st surface that passes through the optical axis and is parallel to a long side of the image pickup element,

the free-form surface of the 1 st free-form surface lens has a positive refractive power with respect to a light ray parallel to the optical axis at an intersection of a circle having a length at a given ratio with respect to a shortest image height from the optical axis and a 2 nd surface passing through the optical axis and parallel to a short side of the image pickup element.

2. The lens system of claim 1,

the given ratio is 40% to 80%.

3. The lens system according to claim 1 or 2,

the lens system has an aperture stop and a lens system,

the 1 st free-form surface lens is located on the object side than the aperture stop.

4. The lens system of claim 3,

the aperture stop has a 2 nd free-form surface lens on the image plane side.

5. The lens system of claim 4,

the 2 nd free-form surface lens is disposed on the most image surface side, and both the object side and the image surface side are free-form surfaces.

6. The lens system according to any one of claims 1 to 5,

the optical lens system includes, in order from an object side, a 1 st lens element and a 2 nd lens element, the 1 st lens element being a meniscus lens having a convex shape on the object side and having negative refractive power, and the 2 nd lens element having negative refractive power.

7. The lens system of claim 6,

the 1 st free-form surface lens is disposed on the image plane side of the 2 nd lens element, and at least the object side is a free-form surface.

8. The lens system according to any one of claims 1 to 7,

at least more than 3 lens elements are provided which are rotationally symmetrical with respect to the optical axis.

9. The lens system of claim 1,

the following condition (1) is satisfied:

ω_LONG＞60° (1)

in this case, the amount of the solvent to be used,

ω_LONG: the maximum half angle of view in the longitudinal direction of the image pickup element.

10. The lens system of claim 1,

the following condition (2) is satisfied:

1＜D_LSHORT/D_SSHORT(2)

in this case, the amount of the solvent to be used,

D_LSHORT: a maximum distance in the longitudinal direction between an image point of incident light in the longitudinal direction of the image pickup device at an angle of view equal to a maximum half angle of view in the short-side direction of the image pickup device and an image point of incident light perpendicular to the image pickup device;

D_SSHORT: the maximum distance in the short side direction between the image point of the incident light with the maximum half angle of view in the short side direction of the imaging element and the image point of the incident light perpendicular to the imaging element.

11. The lens system of claim 1,

the following condition (3) is satisfied:

0.5＜D_SSHORT×ω_LONG/(D_LLONG×ω_SHORT)＜1 (3)

in this case, the amount of the solvent to be used,

ω_LONG: a maximum half angle of view in the longitudinal direction of the image pickup element;

ω_SHORT: a maximum half angle of view in the short side direction of the image pickup element;

D_LLONG: a maximum distance in the longitudinal direction between an image point of incident light at a maximum half angle of view in the longitudinal direction of the image pickup device and an image point of incident light perpendicular to the image pickup device;

D_SSHORT: the maximum distance in the short side direction between the image point of the incident light with the maximum half angle of view in the short side direction of the imaging element and the image point of the incident light perpendicular to the imaging element.

12. The lens system of claim 1,

the following condition (4) is satisfied:

ω_LONG-ω_SHORT＞0 (4)

in this case, the amount of the solvent to be used,

ω_LONG: a maximum half angle of view in the longitudinal direction of the image pickup element;

ω_SHORT: the maximum half angle of view in the short side direction of the image pickup element.

13. The lens system of claim 1,

the following condition (5) is satisfied:

L×Fno./D_LLONG＜40 (5)

in this case, the amount of the solvent to be used,

l: the optical total length of the lens system;

fno.: f value of the lens system;

D_LLONG: an image point of incident light with a maximum half angle of view in a longitudinal direction of the image pickup device, and a maximum image point of incident light perpendicular to the image pickup device in the longitudinal directionA large distance.

14. The lens system of claim 1,

the following condition (6) is satisfied:

n_FREE＜1.7 (6)

in this case, the amount of the solvent to be used,

n_FREE: refractive index of the 1 st or 2 nd free-form surface lens with respect to d-line.

15. The lens system of claim 1,

the lens system further has a lens element and an aperture stop, and satisfies the following condition (7):

-3≤N_o-N_i≤3 (7)

in this case, the amount of the solvent to be used,

N_o: the number of lens elements including the 1 st free-form surface lens on the object side of the aperture stop;

N_i: the number of lens elements on the image plane side of the aperture stop.

16. The lens system of claim 1,

the image pickup device does not include an image circle of the lens system.

17. A camera system includes:

the lens system of claim 1; and

the rectangular image pickup element is disposed at a position where the optical axis forms an image in the lens system.

18. An imaging system includes:

the lens system of claim 1;

the rectangular image pickup element is arranged at a position where the optical axis forms an image in the lens system; and

and an image processing unit that processes the image generated by the image pickup device.

Technical Field

The present disclosure relates to a lens system, a camera system, and an imaging system.

Background

An image formed by a lens of a non-center-projection system is distorted from a rectangular shape, and if a rectangular image pickup device is used, the area of the light receiving surface that is not used is increased without overlapping the optical image and the image pickup device.

In addition, from the viewpoint of object detection and recognition, it is required to greatly enlarge an object in the central portion near the optical axis to form an image on the image pickup element, but it is difficult.

Patent document 1 discloses a method of capturing a panoramic image by a rectangular image sensor. Patent document 1 discloses that a circular image is formed on a rectangular image pickup device as a rectangular image by using a circular lens for a fish-eye objective lens.

Prior art documents

Patent document

Patent document 1: international publication No. 03/101599

Disclosure of Invention

The present disclosure provides a lens system capable of magnifying a subject in a central portion near an optical axis while effectively utilizing a region of a light-sensing surface of a rectangular image pickup element, a camera system including the lens, and an image pickup system.

The lens system of the present disclosure is a lens system that forms an image on a rectangular image pickup element disposed on an optical axis, and includes a 1 st free-form surface lens asymmetric with respect to the optical axis. The free-form surface of the 1 st free-form surface lens has a negative refractive power with respect to a light ray parallel to the optical axis at an intersection of a circle having a length at a given ratio to the shortest image height from the optical axis and a 1 st surface parallel to the long side of the image pickup element and has a positive refractive power with respect to a light ray parallel to the optical axis at an intersection of a circle having a length at a given ratio to the shortest image height from the optical axis and a 2 nd surface parallel to the short side of the image pickup element.

The disclosed camera system is provided with: the above lens system of the present disclosure; and a rectangular image pickup element disposed at a position where the lens system forms an image on an optical axis.

The imaging system of the present disclosure includes: the above lens system of the present disclosure; a rectangular image pickup element disposed at a position where the optical axis of the image pickup element forms an image on the lens system; and an image processing unit that processes the image generated by the image pickup device.

In the present invention, a lens system that forms a substantially rectangular image and magnifies a subject in the center near the optical axis, a camera system including the lens system, and an imaging system can be realized.

Drawings

Fig. 1 is a lens arrangement diagram showing an infinite focus state of a lens system according to embodiment 1.

Fig. 2 is a lens arrangement diagram showing an infinite focus state of the lens system according to embodiment 2.

Fig. 3 is a lens arrangement diagram showing an infinite focus state of the lens system according to embodiment 3.

Fig. 4 is a schematic configuration diagram of a camera system according to embodiment 4.

Fig. 5 is a schematic configuration diagram of an imaging system according to embodiment 5.

Fig. 6 is an aberration diagram showing spherical aberration and field curvature in an infinite focus state of the lens system according to numerical embodiment 1.

Fig. 7 is a diagram showing a relationship between an angle of view and an image point in an infinite focus state of the lens system according to numerical embodiment 1.

Fig. 8 is an aberration diagram showing spherical aberration and field curvature in an infinite focus state of the lens system according to numerical embodiment 2.

Fig. 9 is a diagram showing a relationship between an angle of view and an image point in an infinite focus state of the lens system according to numerical embodiment 2.

Fig. 10 is an aberration diagram showing spherical aberration and field curvature in an infinite focus state of the lens system according to numerical embodiment 3.

Fig. 11 is a diagram showing a relationship between an angle of view and an image point in an infinite focus state of the lens system according to numerical embodiment 3.

Detailed Description

Hereinafter, the embodiments will be described in detail with reference to the drawings as appropriate. However, the above detailed description may be omitted. For example, detailed descriptions of already known matters and repetitive descriptions of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the following description, as will be readily understood by those skilled in the art.

The drawings added and the following description are provided to fully understand the present disclosure by those skilled in the art, and are not intended to limit the subject matter described in the claims.

(embodiment mode 1)

Fig. 1 is a configuration diagram of a lens system according to embodiment 1, showing an infinity focus state.

Fig. 1 (a) is a YZ cross section, and fig. 1 (b) is an XZ cross section, showing a lens system 111 having 8 lens elements, and a rectangular image pickup element 102 having a short side and a long side. The X direction is a direction parallel to the long side of the image pickup device 102, the Y direction is a direction parallel to the short side of the image pickup device 102, and the Z direction is a direction parallel to the optical axis. Further, the YZ cross section is a plane including the optical axis and parallel to the Y direction and the Z direction. The XZ section is a plane including the optical axis and parallel to the X direction and the Z direction.

As shown in fig. 1, the lens system 111 according to embodiment 1 includes 5 lens elements L1 to L5, an aperture stop a, and 3 lens elements L6 to L8 in this order from the object side to the image plane side. The position of the lens system 111 where an image is formed is an image plane of the image pickup device 102. Reference numerals are omitted in fig. 1 (b).

Further, the lens system 111 will be described in detail. The lens system 111 is composed of, in order from the object side to the image surface side, a negative meniscus lens element L1 having a convex surface facing the object side, a biconcave lens element L2, a biconcave lens element L3, a biconvex lens element L4, a positive meniscus lens element L5 having both surfaces formed with aspherical surfaces and having a convex surface facing the object side, an aperture stop a, a biconvex lens element L6, a negative meniscus lens element L7 having a convex surface facing the image surface side, and a positive meniscus lens element L8 having a convex surface facing the object side. Lens element L6 and lens element L7 were cemented. Here, lens element L1 is an example of the 1 st lens element, and lens element L2 is an example of the 2 nd lens element.

In the lens system 111, the lens element L3 and the lens element L8 are free-form surfaces whose both object side and image side are XY polynomials. In fig. 1, the free-form surfaces are denoted by the symbol x. Here, the lens element L3 is an example of a 1 st free-form surface lens, and the lens element L8 is an example of a 2 nd free-form surface lens.

The free-form surface on the image plane side of the lens element L3 has a negative refractive power with respect to a light ray parallel to the optical axis at the intersection of a circle having a length at a given ratio to the shortest image height from the optical axis and an XZ plane (1 st plane) passing through the optical axis and parallel to the long side of the image pickup element, and the free-form surface on the image plane side of the lens element L3 has a positive refractive power with respect to a light ray parallel to the optical axis at the intersection of a circle having a length at a given ratio to the shortest image height from the optical axis and a YZ plane (2 nd plane) passing through the optical axis and parallel to the short side of the image pickup element. Here, in the present embodiment, since the predetermined ratio to the shortest image height corresponds to all ratios, the free-form surface on the image plane side of the lens element L3 has negative refractive power with respect to the light rays parallel to the optical axis at all intersections with the XZ plane, and has positive refractive power with respect to the light rays parallel to the optical axis at all intersections with the YZ plane. The surface data of each lens element will be described later. The surface shapes of the free-form surface lens and the aspherical surface lens are expressed by the shapes near the optical axis (vertex) in the Y direction.

(embodiment mode 2)

Fig. 2 is a configuration diagram of a lens system according to embodiment 2. Fig. 2 (a) is a YZ cross section, and fig. 2 (b) is an XZ cross section, and shows a lens system 121 including 8 lens elements, and a rectangular image pickup element 102 having a short side and a long side. In fig. 2 (b), reference numerals are omitted. The lens system 121 according to embodiment 2 is similar to the lens system 111 according to embodiment 1 in the number of lens elements, the type of lens elements, and the order of arrangement, and is different in the surface data of the lens system elements L1 to L8. The different points regarding the surface data will be described later. In the lens system 121, the lens element L1 is an example of a 1 st lens element, the lens element L2 is an example of a 2 nd lens element, the lens element L3 is an example of a 1 st free-form surface lens, and the lens element L8 is an example of a 2 nd free-form surface lens.

In the lens system 121, too: the free-form surface on the image plane side of the lens element L3 has negative refractive power with respect to light rays parallel to the optical axis at all intersections with the XZ plane, and has positive refractive power with respect to light rays parallel to the optical axis at all intersections with the YZ plane.

(embodiment mode 3)

Fig. 3 is a configuration diagram of a lens system according to embodiment 3. Fig. 3 (a) is a YZ cross section, and fig. 3 (b) is an XZ cross section, showing a lens system 131 having 8 lens elements, and a rectangular image pickup element 102 having a short side and a long side. In fig. 3 (b), reference numerals are omitted. The lens system 131 according to embodiment 3 has the same number of lens elements as compared with the lens system 111 according to embodiment 1, and has different types of lens elements L2 and different surface data of the lens system elements L1 to L8. The lens element L2 is a negative meniscus lens shape with the convex surface facing the object side. The different points regarding the surface data will be described later. In the lens system 131, the lens element L1 is an example of a 1 st lens element, the lens element L2 is an example of a 2 nd lens element, the lens element L3 is an example of a 1 st free-form surface lens, and the lens element L8 is an example of a 2 nd free-form surface lens.

In the lens system 131, too: the free-form surface on the image plane side of the lens element L3 has negative refractive power with respect to light rays parallel to the optical axis at all intersections with the XZ plane, and has positive refractive power with respect to light rays parallel to the optical axis at all intersections with the YZ plane.

(common configuration of embodiments 1 to 3)