阅读说明：本技术 一种镜头 (Lens ) 是由 林法官 刘凯 丁洪兴 杜艳芬 于 2019-09-12 设计创作，主要内容包括：本发明公开了一种镜头,所述镜头包括：由物侧至像侧依次排列的第一透镜组和第二透镜组；所述第一透镜组的位置固定,第二透镜组可沿光轴进行移动；透镜组满足以下条件：1.2<|f调/f系统|<1.3；其中,f调为第二透镜组的焦距,f系统为所述镜头的系统焦距。由于在本发明实施例中,在镜头中按照特定的顺序由物侧至像侧依次排列两个透镜组,并且镜头中的透镜组满足：1.2<|f调/f系统|<1.3；在一定程度上,增大了镜头的视场、口径、焦距、分辨率,并且满足近物距的要求。(The invention discloses a lens, comprising: a first lens group and a second lens group arranged in order from an object side to an image side; the position of the first lens group is fixed, and the second lens group can move along the optical axis; the lens group satisfies the following conditions: 1.2< | f-modulation/f system | < 1.3; and f is the focal length of the second lens group, and the f system is the system focal length of the lens. Since, in the embodiment of the present invention, two lens groups are arranged in order from the object side to the image side in the lens barrel in a specific order, and the lens groups in the lens barrel satisfy: 1.2< | f-modulation/f system | < 1.3; to a certain extent, the field of view, the caliber, the focal length and the resolution of the lens are increased, and the requirement of the close object distance is met.)

1. The lens is characterized by comprising a first lens group and a second lens group which are sequentially arranged from an object side to an image side;

the position of the first lens group is fixed, and the second lens group can move along the optical axis;

the lens group satisfies the following conditions:

1.2< | f-modulation/f system | < 1.3;

and f is the focal length of the second lens group, and the f system is the system focal length of the lens.

2. The lens barrel according to claim 1, wherein the first lens group includes a first negative power lens and a first positive power lens arranged in order from an object side to an image side.

3. The lens barrel as claimed in claim 2, wherein the first negative power lens includes a biconcave lens; the first positive power lens includes a convex lens.

4. The lens barrel according to claim 1, wherein the second lens group includes a second positive power lens, a first sub-lens group, a second sub-lens group, a fifth positive power lens, and a sixth positive power lens, which are arranged in order from the object side to the image side;

the first sub-lens group comprises a third positive focal power lens and a second negative focal power lens;

the second sub-lens group includes a third negative power lens and a fourth positive power lens.

5. The lens barrel as claimed in claim 4, wherein the second positive power lens includes a convex lens; the third positive power lens comprises a convex lens; the second negative power lens comprises a concave lens; the third negative power lens comprises a concave lens; the fourth positive power lens comprises a convex lens; the fifth positive power lens comprises a convex lens; the sixth positive power lens includes a convex lens.

6. The lens barrel according to claim 4, wherein an aperture stop is disposed between the first sub-lens group and the second sub-lens group.

7. The lens barrel according to claim 1, wherein an image plane is disposed on an image side of the second lens group.

8. The lens barrel according to claim 7, wherein a filter is disposed between the second lens group and an imaging surface.

9. The lens barrel as claimed in claim 2, wherein the refractive index of the first positive power lens is greater than 1.9.

10. The lens barrel according to claim 4 or 5, wherein the third positive power lens and the fourth positive power lens each have an abbe number greater than 60.

Technical Field

The invention relates to the technical field of optical imaging, in particular to a lens.

Background

Machine vision is to use a machine to replace human eyes for measurement and judgment. The machine vision system is a machine vision product, namely an image pickup device converts a target to be detected into image signals, and then an image processing system performs various operations on the signals to extract target characteristics, so that the control of the action of field equipment is realized. The image pickup Device includes a Complementary Metal-Oxide-Semiconductor (CMOS), a Charge-coupled Device (CCD), and the like.

At present, machine vision lenses on the market cannot meet the requirements of large view field, large caliber, long focal length, high resolution and close object distance, so that the requirements of high-end products cannot be met.

Disclosure of Invention

The embodiment of the invention provides a lens, which is used for solving the problem that the machine vision lens in the current market can not meet the requirements of large view field, large caliber, long focal length, high resolution and close object distance.

An embodiment of the present invention provides a lens barrel, including a first lens group and a second lens group sequentially arranged from an object side to an image side;

the position of the first lens group is fixed, and the second lens group can move along the optical axis;

the lens group satisfies the following conditions:

1.2< | f-modulation/f system | < 1.3;

and f is the focal length of the second lens group, and the f system is the system focal length of the lens.

Further, the first lens group includes a first negative power lens and a first positive power lens arranged in order from the object side to the image side.

Further, the first negative power lens comprises a biconcave lens; the first positive power lens includes a convex lens.

Further, the second lens group comprises a second positive power lens, a first sub-lens group, a second sub-lens group, a fifth positive power lens and a sixth positive power lens which are arranged in sequence from the object side to the image side;

the first sub-lens group comprises a third positive focal power lens and a second negative focal power lens;

the second sub-lens group includes a third negative power lens and a fourth positive power lens.

Further, the second positive power lens includes a convex lens; the third positive power lens comprises a convex lens; the second negative power lens comprises a concave lens; the third negative power lens comprises a concave lens; the fourth positive power lens comprises a convex lens; the fifth positive power lens comprises a convex lens; the sixth positive power lens includes a convex lens.

Further, a diaphragm is arranged between the first sub-lens group and the second sub-lens group.

Further, an image plane is arranged on the image side of the second lens group.

Further, an optical filter is arranged between the second lens group and the imaging surface.

Further, the refractive index of the first positive power lens is greater than 1.9.

Further, the abbe numbers of the third positive power lens and the fourth positive power lens are both greater than 60.

An embodiment of the present invention provides a lens, including: a first lens group and a second lens group arranged in order from an object side to an image side; the position of the first lens group is fixed, and the second lens group can move along the optical axis; the lens group satisfies the following conditions: 1.2< | f-modulation/f system | < 1.3; and f is the focal length of the second lens group, and the f system is the system focal length of the lens. Since, in the embodiment of the present invention, two lens groups are arranged in order from the object side to the image side in the lens barrel in a specific order, and the lens groups in the lens barrel satisfy: 1.2< | f-modulation/f system | < 1.3; to a certain extent, the field of view, the caliber, the focal length and the resolution of the lens are increased, and the requirement of the close object distance is met.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic view of a lens provided in an embodiment of the present invention;

fig. 2 is a schematic view of a lens provided in embodiment 1 of the present invention;

FIG. 3 is a graph of transfer function (MTF) at infinity for a system provided in embodiment 1 of the present invention;

FIG. 4 is a graph of transfer function (MTF) of the system of example 1 of the present invention at magnification-0.103;

FIG. 5 is a graph of the transfer function (MTF) of the system of example 1 of the present invention at magnification-0.189;

fig. 6 is a schematic view of a lens provided in embodiment 2 of the present invention;

FIG. 7 is a graph of transfer function (MTF) at infinity for the system provided in embodiment 2 of the present invention;

FIG. 8 is a graph of transfer function (MTF) of the system of example 2 of the present invention at magnification-0.103;

fig. 9 is a graph of the transfer function (MTF) of the system provided in embodiment 2 of the present invention at magnification-0.208.

Detailed Description

The present invention will be described in further detail with reference to the attached drawings, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Fig. 1 is a schematic view of a lens barrel according to an embodiment of the present disclosure, the lens barrel including a first lens group G1 and a second lens group G2 arranged in order from an object side to an image side;

the position of the first lens group G1 is fixed, and the second lens group G2 can move along the optical axis;

the lens group satisfies the following conditions:

1.2< | f-modulation/f system | < 1.3;

and f is the focal length of the second lens group, and the f system is the system focal length of the lens.

According to the lens provided by the embodiment of the invention, the fine adjustment of the focal length is realized by changing the position of the second lens group G2 along the optical axis, so that the object distance during focusing is changed. Since, in the embodiment of the present invention, two lens groups are arranged in order from the object side to the image side in the lens barrel in a specific order, and the lens groups in the lens barrel satisfy: 1.2< | f-modulation/f system | < 1.3; to a certain extent, the field of view, the caliber, the focal length and the resolution of the lens are increased, and the requirement of the close object distance is met.

In order to improve the imaging quality of the lens, in the embodiment of the invention, the first lens group G1 includes a first negative power lens 1 and a first positive power lens 2 arranged in order from the object side to the image side. The first negative power lens 1 includes a biconcave lens; the first positive power lens 2 includes a convex lens.

The second lens group G2 comprises a second positive power lens 3, a first sub-lens group C1, a second sub-lens group C2, a fifth positive power lens 8 and a sixth positive power lens 9 which are arranged in sequence from the object side to the image side;

the first sub-lens group C1 includes a third positive power lens 4 and a second negative power lens 5;

the second sub-lens group C2 includes a third negative power lens 6 and a fourth positive power lens 7.

The second positive power lens comprises a convex lens; the third positive power lens comprises a convex lens; the second negative power lens comprises a concave lens; the third negative power lens comprises a concave lens; the fourth positive power lens comprises a convex lens; the fifth positive power lens comprises a convex lens; the sixth positive power lens includes a convex lens.

In order to shorten the length of the lens and make the system compact, the third positive power lens and the second negative power lens can be connected by gluing or fitting. In order to ensure that the third positive focal power lens and the second negative focal power lens can realize gluing connection or attaching connection, the curvature radius of the surface, facing the image side, of the third positive focal power lens is the same as the curvature radius of the surface, facing the object side, of the second negative focal power lens. The third negative power lens and the fourth positive power lens can be connected in a gluing mode or a fitting mode. In order to ensure that the third negative focal power lens and the fourth positive focal power lens can realize gluing connection or attaching connection, the curvature radius of the surface, facing the image side, of the third negative focal power lens is the same as the curvature radius of the surface, facing the object side, of the fourth positive focal power lens.

In the embodiment of the present invention, an aperture stop P is disposed between the first sub-lens group and the second sub-lens group.

The aperture size of the aperture diaphragm determines the aperture value of the system and the depth of field during shooting, the aperture size can be fixed, or the aperture diaphragm with adjustable aperture can be placed according to the requirement to realize the adjustment of the clear aperture, namely the purpose of changing the aperture value of the system and the depth of field is achieved.

In the embodiment of the invention, an image plane M is arranged on the image side of the second lens group, and a filter N is arranged between the second lens group and the image plane. The filter N is used to select the desired radiation band.

In order to increase the refractive index of the lens and reduce the total length of the lens, in the embodiment of the invention, the refractive index of the first positive power lens is more than 1.9. For example, the refractive index of the first positive power lens may be 2.0, 2.1, etc. And the refractive index of the first positive focal power lens is larger than 1.9, so that the spherical aberration can be reduced, and the image quality can be improved.

In the embodiment of the invention, in order to realize day and night confocal and no thermalization in the full focal section of the lens, namely, clear imaging can be realized in the range of-40 ℃ to 80 ℃, in the embodiment of the invention, the abbe numbers of the third positive power lens and the fourth positive power lens are both more than 60. For example, the abbe numbers of the third positive power lens and the fourth positive power lens may be 65, 68, 70, and the like. And, abbe numbers of the third positive power lens and the fourth positive power lens may be the same or different. In addition, the abbe numbers of the third positive focal power lens and the fourth positive focal power lens are both larger than 60, and the chromatic aberration of the image can be reduced, so that the image quality is improved.

The following exemplifies the lens parameters provided by the embodiment of the present invention.