Lens
阅读说明：本技术 一种镜头 (Lens ) 是由 林法官 刘凯 丁洪兴 于 2019-10-23 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、第二透镜组、光栏、第三透镜组、第四透镜组、滤光片和像面；所述第一透镜组和第三透镜组的位置固定,第二透镜组和第四透镜组可沿光轴进行移动；透镜组满足以下条件：0.5<f3*f4/(f2*f2)<0.7；其中,f2为第二透镜组的焦距,f3为第三透镜组的焦距,f4为第四透镜组的焦距。由于在镜头中按照特定的顺序由物侧至像侧依次排列四个透镜组,所述第一透镜组和第三透镜组的位置固定,第二透镜组和第四透镜组可沿光轴进行移动实现镜头变焦,并且镜头中的透镜组满足：0.5<f3*f4/(f2*f2)<0.7,实现了一种超星光变焦镜头。(The invention discloses a lens, which comprises a first lens group, a second lens group, a diaphragm, a third lens group, a fourth lens group, an optical filter and an image plane, wherein the first lens group, the second lens group, the diaphragm, the third lens group, the fourth lens group, the optical filter and the image plane are sequentially arranged from an object side to an image side; the positions of the first lens group and the third lens group are fixed, and the second lens group and the fourth lens group can move along the optical axis; the lens group satisfies the following conditions: 0.5< f3 f4/(f2 f2) < 0.7; where f2 is the focal length of the second lens group, f3 is the focal length of the third lens group, and f4 is the focal length of the fourth lens group. Because four lens groups are arranged in the lens in order from the object side to the image side according to a specific sequence, the positions of the first lens group and the third lens group are fixed, the second lens group and the fourth lens group can move along the optical axis to realize the zoom of the lens, and the lens groups in the lens meet the following conditions: 0.5< f3 f4/(f2 f2) <0.7, realizing a superstar zoom lens.)
1. A lens is characterized by comprising a first lens group, a second lens group, a diaphragm, a third lens group, a fourth lens group, an optical filter and an image plane which are sequentially arranged from an object side to an image side;
the positions of the first lens group and the third lens group are fixed, and the second lens group and the fourth lens group can move along the optical axis;
the lens group satisfies the following conditions:
0.5<f3*f4/(f2*f2)<0.7；
where f2 is the focal length of the second lens group, f3 is the focal length of the third lens group, and f4 is the focal length of the fourth lens group.
2. The lens barrel according to claim 1, wherein the first lens group includes a first sub-lens group and a second positive power lens arranged in order from an object side to an image side.
3. The lens barrel according to claim 2, wherein the first sub-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;
the curvature radius of one surface of the first negative focal power lens facing the image side is the same as that of one surface of the first positive focal power lens facing the object side;
the first negative-power lens comprises a meniscus concave lens, and one surface of the meniscus concave lens facing the object side is a convex surface;
the first positive power lens comprises a biconvex lens;
the second positive power lens comprises a meniscus convex lens, and one surface of the meniscus convex lens facing the object side is a convex surface.
4. The lens barrel according to claim 1, wherein the second lens group includes a second negative power lens and a second sub-lens group arranged in order from the object side to the image side.
5. The lens barrel according to claim 4, wherein the second sub-lens group includes a third negative power lens and a third positive power lens arranged in order from the object side to the image side;
the curvature radius of one surface of the third negative focal power lens facing the image side is the same as that of one surface of the third positive focal power lens facing the object side;
the second negative-power lens comprises a meniscus concave lens, and one surface of the meniscus concave lens facing the object side is a convex surface;
the third negative power lens comprises a biconcave lens;
the third positive power lens comprises a convex lens, and one surface of the convex lens facing the object side is a convex surface.
6. The lens barrel according to claim 3, wherein the third lens group includes a fourth positive power lens, a third sub-lens group, a fourth sub-lens group, and a fifth sub-lens group, which are arranged in order from the object side to the image side.
7. The lens barrel according to claim 6, wherein the third sub-lens group includes a fourth negative power lens and a fifth positive power lens arranged in order from the object side to the image side; the curvature radius of one surface of the fourth negative focal power lens facing the image side is the same as that of one surface of the fifth positive focal power lens facing the object side;
the fourth sub-lens group comprises a sixth positive focal power lens and a fifth negative focal power lens which are arranged in sequence from the object side to the image side; the curvature radius of one surface of the sixth positive focal power lens facing the image side is the same as that of one surface of the fifth negative focal power lens facing the object side;
the fifth sub-lens group comprises a seventh positive focal power lens and a sixth negative focal power lens which are arranged in sequence from the object side to the image side; the curvature radius of one surface of the seventh positive focal power lens facing the image side is the same as that of one surface of the sixth negative focal power lens facing the object side;
the fourth positive power lens comprises a convex lens, and one surface of the convex lens facing the object side is a convex surface;
the fourth negative-power lens comprises a meniscus concave lens, and one surface of the meniscus concave lens facing the object side is a convex surface;
the fifth positive power lens comprises a meniscus convex lens, and one surface of the meniscus convex lens facing the object side is a convex surface;
the sixth positive power lens comprises a convex lens, and one surface of the convex lens facing the object side is a convex surface;
the fifth negative focal power lens comprises a concave lens, and one surface of the concave lens facing the image side is a concave surface;
the seventh positive focal power lens comprises a meniscus convex lens, and one surface of the meniscus convex lens facing the image side is a convex surface;
the sixth negative power lens includes a biconcave lens.
8. The lens barrel according to claim 1, wherein the fourth lens group includes an eighth positive power lens, a ninth positive power lens, a tenth positive power lens, and a sixth sub-lens group, which are arranged in order from the object side to the image side.
9. The lens barrel according to claim 8, wherein the sixth sub-lens group includes a seventh negative power lens and an eleventh positive power lens arranged in order from the object side to the image side;
the curvature radius of one surface of the seventh negative focal power lens facing the image side is the same as that of one surface of the eleventh positive focal power lens facing the object side;
the eighth positive power lens includes a biconvex lens;
the ninth positive power lens includes a biconvex lens;
the tenth positive power lens comprises a meniscus convex lens, and one surface of the meniscus convex lens facing the object side is a convex surface;
the seventh negative-power lens comprises a concave lens, and one surface of the concave lens facing the object side is a concave surface;
the eleventh positive power lens includes a convex lens, and a surface thereof facing the image side is convex.
10. The lens barrel as recited in claim 6, wherein the fourth positive power lens has a refractive index greater than 1.85;
the abbe numbers of the first positive focal power lens, the second positive focal power lens, the fifth positive focal power lens and the sixth positive focal power lens are all larger than 65.
Technical Field
The invention relates to the technical field of optical imaging, in particular to a lens.
Background
With social progress, the requirements of people on video monitoring cameras are increasingly improved, and currently, the monitoring zoom lens is widely applied to daily life of people, but the conventional security monitoring lens has the following defects:
a typical zoom lens includes 5-group zoom lenses each including lens groups having positive, negative, positive, and negative powers, which are arranged in order from an object side to an image side. In the zoom lens, the first lens group, the third lens group and the fifth lens group are fixed, and the second lens group is moved in the optical axis direction to perform magnification change. Further, by moving the fourth lens group in the direction of the optical axis, correction of image plane variation and focusing accompanying magnification change are performed. The aperture of the zoom lens is only 1.4, the requirement of super starlight F1.0 cannot be met, and the focal length of the telephoto end is not long enough. Therefore, it becomes important to provide a superstar zoom lens.
Disclosure of Invention
The embodiment of the invention provides a lens, which is used for providing a super-star zoom lens.
The embodiment of the invention provides a lens, which comprises a first lens group, a second lens group, a diaphragm, a third lens group, a fourth lens group, an optical filter and an image plane, wherein the first lens group, the second lens group, the diaphragm, the third lens group, the fourth lens group, the optical filter and the image plane are sequentially arranged from an object side to an image side;
the positions of the first lens group and the third lens group are fixed, and the second lens group and the fourth lens group can move along the optical axis;
the lens group satisfies the following conditions:
0.5<f3*f4/(f2*f2)<0.7；
where f2 is the focal length of the second lens group, f3 is the focal length of the third lens group, and f4 is the focal length of the fourth lens group.
Further, the first lens group includes a first sub-lens group and a second positive power lens arranged in order from the object side to the image side.
Further, the first sub-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;
the curvature radius of one surface of the first negative focal power lens facing the image side is the same as that of one surface of the first positive focal power lens facing the object side;
the first negative-power lens comprises a meniscus concave lens, and one surface of the meniscus concave lens facing the object side is a convex surface;
the first positive power lens comprises a biconvex lens;
the second positive power lens comprises a meniscus convex lens, and one surface of the meniscus convex lens facing the object side is a convex surface.
Further, the second lens group includes a second negative power lens and a second sub-lens group arranged in order from the object side to the image side.
Further, the second sub-lens group includes a third negative power lens and a third positive power lens arranged in order from the object side to the image side;
the curvature radius of one surface of the third negative focal power lens facing the image side is the same as that of one surface of the third positive focal power lens facing the object side;
the second negative-power lens comprises a meniscus concave lens, and one surface of the meniscus concave lens facing the object side is a convex surface;
the third negative power lens comprises a biconcave lens;
the third positive power lens comprises a convex lens, and one surface of the convex lens facing the object side is a convex surface.
Further, the third lens group includes a fourth positive power lens, a third sub-lens group, a fourth sub-lens group, and a fifth sub-lens group, which are arranged in order from the object side to the image side.
Further, the third sub-lens group includes a fourth negative power lens and a fifth positive power lens arranged in order from the object side to the image side; the curvature radius of one surface of the fourth negative focal power lens facing the image side is the same as that of one surface of the fifth positive focal power lens facing the object side;
the fourth sub-lens group comprises a sixth positive focal power lens and a fifth negative focal power lens which are arranged in sequence from the object side to the image side; the curvature radius of one surface of the sixth positive focal power lens facing the image side is the same as that of one surface of the fifth negative focal power lens facing the object side;
the fifth sub-lens group comprises a seventh positive focal power lens and a sixth negative focal power lens which are arranged in sequence from the object side to the image side; the curvature radius of one surface of the seventh positive focal power lens facing the image side is the same as that of one surface of the sixth negative focal power lens facing the object side;
the fourth positive power lens comprises a convex lens, and one surface of the convex lens facing the object side is a convex surface;
the fourth negative-power lens comprises a meniscus concave lens, and one surface of the meniscus concave lens facing the object side is a convex surface;
the fifth positive power lens comprises a meniscus convex lens, and one surface of the meniscus convex lens facing the object side is a convex surface;
the sixth positive power lens comprises a convex lens, and one surface of the convex lens facing the object side is a convex surface;
the fifth negative focal power lens comprises a concave lens, and one surface of the concave lens facing the image side is a concave surface;
the seventh positive focal power lens comprises a meniscus convex lens, and one surface of the meniscus convex lens facing the image side is a convex surface;
the sixth negative power lens includes a biconcave lens.
Further, the fourth lens group includes an eighth positive power lens, a ninth positive power lens, a tenth positive power lens, and a sixth sub-lens group, which are arranged in order from the object side to the image side.
Further, the sixth sub-lens group includes a seventh negative power lens and an eleventh positive power lens arranged in order from the object side to the image side;
the curvature radius of one surface of the seventh negative focal power lens facing the image side is the same as that of one surface of the eleventh positive focal power lens facing the object side;
the eighth positive power lens includes a biconvex lens;
the ninth positive power lens includes a biconvex lens;
the tenth positive power lens comprises a meniscus convex lens, and one surface of the meniscus convex lens facing the object side is a convex surface;
the seventh negative-power lens comprises a concave lens, and one surface of the concave lens facing the object side is a concave surface;
the eleventh positive power lens includes a convex lens, and a surface thereof facing the image side is convex.
Further, the refractive index of the fourth positive power lens is greater than 1.85;
the abbe numbers of the first positive focal power lens, the second positive focal power lens, the fifth positive focal power lens and the sixth positive focal power lens are all larger than 65.
The embodiment of the invention provides a lens, which comprises a first lens group, a second lens group, a diaphragm, a third lens group, a fourth lens group, an optical filter and an image plane, wherein the first lens group, the second lens group, the diaphragm, the third lens group, the fourth lens group, the optical filter and the image plane are sequentially arranged from an object side to an image side; the positions of the first lens group and the third lens group are fixed, and the second lens group and the fourth lens group can move along the optical axis; the lens group satisfies the following conditions: 0.5< f3 f4/(f2 f2) < 0.7; where f2 is the focal length of the second lens group, f3 is the focal length of the third lens group, and f4 is the focal length of the fourth lens group. Since in the embodiment of the present invention, four lens groups are arranged in order from the object side to the image side in a lens barrel in a specific order, the positions of the first lens group and the third lens group are fixed, the second lens group and the fourth lens group can move along the optical axis to realize lens zooming, and the lens groups in the lens barrel satisfy: 0.5< f3 f4/(f2 f2) <0.7, realizing a superstar zoom lens.
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 structure according to an embodiment of the present invention;
fig. 2 is a schematic view of a lens structure provided in embodiment 1 of the present invention;
fig. 3 is a graph of a transfer function (MTF) of a lens provided in embodiment 1 of the present invention at a focal length end of 25 mm;
fig. 4 is a graph of a transfer function (MTF) of a lens provided in embodiment 1 of the present invention at a 65mm focal length end;
fig. 5 is a schematic view of a lens structure provided in
fig. 6 is a graph of transfer function (MTF) of a lens provided in
fig. 7 is a graph of transfer function (MTF) of the lens provided in
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 embodiment 1 of the present disclosure, where the lens barrel includes a first lens group G1, a second lens group G2, a diaphragm P, a third lens group G3, a fourth lens group G4, a filter N, and an image plane M, which are arranged in order from an object side to an image side;
the positions of the first lens group and the third lens group are fixed, and the second lens group and the fourth lens group can move along the optical axis;
the lens group satisfies the following conditions:
0.5<f3*f4/(f2*f2)<0.7；
where f2 is the focal length of the second lens group, f3 is the focal length of the third lens group, and f4 is the focal length of the fourth lens group.
The lens barrel can realize zooming by changing the positions of lens groups, wherein the positions of the first lens group and the third lens group are fixed, and the second lens group and the fourth lens group can move along the optical axis to realize zooming. That is, the second lens group can be moved in position between the first lens group and the diaphragm. The second lens group can be close to the first lens group and far away from the diaphragm; or far away from the first lens group and close to the diaphragm. The fourth lens group may be moved in a position between the third lens group and the filter. The fourth lens group may be close to the third lens group, far from the filter; or far away from the third lens group and close to the filter. The second lens group moves in the optical axis direction to zoom, and is called a zoom group or a magnification-varying group. The fourth lens group is moved in the direction of the optical axis to compensate for the image point variation of the second lens group at the image plane to be zero, so that the image plane does not move while zooming is performed, which is called a compensation group. In addition, when the object of interest moves, the image is focused sharply by finely adjusting the fourth lens group. In general, in the lens system, the fourth lens group functions as a compensation group and a focusing group. Some zoom lenses additionally use a lens group as a focusing group to achieve a focusing function, such as an electric two-variable lens and an electric three-variable lens with high magnification (30 times or 60 times).
Because four lens groups are arranged in the lens in order from the object side to the image side according to a specific sequence, the positions of the first lens group and the third lens group are fixed, the second lens group and the fourth lens group can move along the optical axis to realize the zoom of the lens, and the lens groups in the lens meet the following conditions: 0.5< f3 f4/(f2 f2) <0.7, realizing a superstar zoom lens.
In order to further improve the imaging quality of the lens barrel, in the embodiment of the present invention, the first lens group includes a first sub-lens group and a second positive power lens 3 arranged in order from the object side to the image side.
The first sub-lens group comprises a first negative focal power lens 1 and a first positive
the curvature radius of one surface of the first negative focal power lens facing the image side is the same as that of one surface of the first positive focal power lens facing the object side;
the first negative-power lens comprises a meniscus concave lens, and one surface of the meniscus concave lens facing the object side is a convex surface;
the first positive power lens comprises a biconvex lens;
the second positive power lens comprises a meniscus convex lens, and one surface of the meniscus convex lens facing the object side is a convex surface.
To further enable the system to be compact, the first negative power lens 1 and the first
In order to further improve the imaging quality of the lens barrel, in the embodiment of the invention, the second lens group comprises a second negative power lens 4 and a second sub-lens group which are arranged in sequence from the object side to the image side.
The second sub-lens group comprises a third negative power lens 5 and a third positive power lens 6 which are arranged in sequence from the object side to the image side;
the curvature radius of one surface of the third negative focal power lens facing the image side is the same as that of one surface of the third positive focal power lens facing the object side;
the second negative-power lens comprises a meniscus concave lens, and one surface of the meniscus concave lens facing the object side is a convex surface;
the third negative power lens comprises a biconcave lens;
the third positive power lens comprises a convex lens, and one surface of the convex lens facing the object side is a convex surface.
To further enable the system to be compact, the third negative power lens 5 and the third positive power lens 6 may be cemented or cemented.
In order to further improve the imaging quality of the lens barrel, in the embodiment of the invention, the third lens group comprises a fourth positive power lens 7, a third sub-lens group, a fourth sub-lens group and a fifth sub-lens group which are arranged in sequence from the object side to the image side.
The third sub-lens group comprises a fourth negative power lens 8 and a fifth positive power lens 9 which are arranged in sequence from the object side to the image side; the curvature radius of one surface of the fourth negative focal power lens facing the image side is the same as that of one surface of the fifth positive focal power lens facing the object side;
the fourth sub-lens group comprises a sixth
the fifth sub-lens group includes a seventh positive power lens 12 and a sixth negative power lens 13 arranged in order from the object side to the image side; the curvature radius of one surface of the seventh positive focal power lens facing the image side is the same as that of one surface of the sixth negative focal power lens facing the object side;
the fourth positive power lens comprises a convex lens, and one surface of the convex lens facing the object side is a convex surface;
the fourth negative-power lens comprises a meniscus concave lens, and one surface of the meniscus concave lens facing the object side is a convex surface;
the fifth positive power lens comprises a meniscus convex lens, and one surface of the meniscus convex lens facing the object side is a convex surface;
the sixth positive power lens comprises a convex lens, and one surface of the convex lens facing the object side is a convex surface;
the fifth negative focal power lens comprises a concave lens, and one surface of the concave lens facing the image side is a concave surface;
the seventh positive focal power lens comprises a meniscus convex lens, and one surface of the meniscus convex lens facing the image side is a convex surface;
the sixth negative power lens includes a biconcave lens.
To further enable the system to be compact, the fourth negative power lens and the fifth positive power lens may be cemented or otherwise snugly connected. The sixth positive power lens and the fifth negative power lens may be cemented or cemented. The seventh positive power lens and the sixth negative power lens may be cemented or adhesively connected.
In order to further improve the imaging quality of the lens barrel, in the embodiment of the invention, the fourth lens group comprises an eighth positive power lens 14, a ninth positive power lens 15, a tenth positive power lens 16 and a sixth sub-lens group which are arranged in sequence from the object side to the image side.
The sixth sub-lens group includes a seventh negative power lens 17 and an eleventh positive power lens 18 arranged in order from the object side to the image side;
the curvature radius of one surface of the seventh negative focal power lens facing the image side is the same as that of one surface of the eleventh positive focal power lens facing the object side;
the eighth positive power lens includes a biconvex lens;
the ninth positive power lens includes a biconvex lens;
the tenth positive power lens comprises a meniscus convex lens, and one surface of the meniscus convex lens facing the object side is a convex surface;
the seventh negative-power lens comprises a concave lens, and one surface of the concave lens facing the object side is a concave surface;
the eleventh positive power lens includes a convex lens, and a surface thereof facing the image side is convex.
To further enable the system to be compact, the seventh negative power lens and the eleventh positive power lens may be cemented or otherwise snugly connected.
In the embodiment of the invention, in order to realize clear imaging at the lens between-40 ℃ and 80 ℃, in the embodiment of the invention, the abbe numbers of the first positive power lens, the second positive power lens, the fifth positive power lens and the sixth positive power lens are all more than 65. In addition, the abbe numbers of the first positive focal power lens, the second positive focal power lens, the fifth positive focal power lens and the sixth positive focal power lens are all larger than 65, and the chromatic aberration of an image can be reduced, so that the imaging quality is improved. Moreover, abbe numbers of the first positive power lens, the second positive power lens, the fifth positive power lens and the sixth positive power lens may be the same or different.
In order to improve the imaging quality of the lens and reduce the total length of the lens, in the embodiment of the invention, the refractive index of the fourth positive power lens is greater than 1.85. And the refractive index of the fourth positive focal power lens is larger than 1.85, so that the spherical aberration can be reduced, and the imaging quality is improved.
In the embodiment of the invention, a diaphragm P is arranged between the second lens group and the third lens group.
The diaphragm comprises an aperture diaphragm, 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 requirements to realize the adjustment of the clear aperture, namely the purposes of changing the aperture value of the system and changing the depth of field are achieved.
And an optical filter N is arranged between the fourth lens group and the image surface, and the optical filter is an optical device for selecting a required radiation waveband.
The optical performance of the lens provided by the embodiment of the invention is as follows: the focal length is about 25-65mm, the aperture Fno is about 1.0, the
By adopting the technical scheme, the technical requirements of high resolution, super starlight, no thermalization and the like are met, and the face recognition device is suitable for the remote face recognition requirement.
The following exemplifies the lens parameters provided by the embodiment of the present invention.
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