Lens
阅读说明：本技术 一种镜头 (Lens ) 是由 邢圆圆 刘凯 郭安峰 于 2021-08-25 设计创作，主要内容包括：本发明公开了一种镜头,由物侧至像侧依次排列第一透镜组、第二透镜组、孔径光阑、第三透镜组、第四透镜组、第五透镜组和分光装置构成；所述分光装置的每个出光侧依次包括滤光片和像面；透镜组满足以下条件：其中,f-(2)为第二透镜组的焦距,f-(4)为第四透镜组的焦距,f-(w)为镜头在短焦状态下的焦距,f-(T)为镜头在长焦状态下的焦距,FOV-(w)为镜头在短焦状态下的视场角,FOV-(T)为镜头在长焦状态下的视场角。实现大靶面、大光圈、低成本的高分辨率镜头。(The invention discloses a lens, which consists of a first lens group, a second lens group, an aperture diaphragm, a third lens group, a fourth lens group, a fifth lens group and a light splitting device which are sequentially arranged from an object side to an image side; each light emitting side of the light splitting device sequentially comprises an optical filter and an image plane; the lens group satisfies the following conditions: wherein f is 2 Is the focal length of the second lens group, f 4 Is the focal length of the fourth lens group, f w Is the focal length of the lens in the short focus state, f T For the focal length, FOV, of the lens in tele state w For the lens in short focusAngle of view, FOV T The angle of view of the lens in the telephoto state. The high-resolution lens with large target surface, large aperture and low cost is realized.)
1. A lens is characterized in that the lens is composed of a first lens group, a second lens group, an aperture diaphragm, a third lens group, a fourth lens group, a fifth lens group and a light splitting device which are sequentially arranged from an object side to an image side; each light emitting side of the light splitting device sequentially comprises an optical filter and an image plane;
the positions of the first lens group, the third lens group and the fifth 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:
wherein f is2Is the focal length of the second lens group, f4Is the focal length of the fourth lens group, fwIs the focal length of the lens in the short focus state, fTFor the focal length, FOV, of the lens in tele statewFor the field angle, FOV, of the lens in short focusTThe field angle of the lens in a long-focus state is defined;
the first lens group consists of a first negative focal power lens, a first positive focal power lens and a second positive focal power lens which are arranged in sequence from the object side to the image side;
the second lens group consists of a second negative focal power lens, a third negative focal power lens and a third positive focal power lens which are arranged in sequence from the object side to the image side;
the third lens group consists of a fourth positive focal power lens, a fifth positive focal power lens, a fourth negative focal power lens, a sixth positive focal power lens, a seventh positive focal power lens and a fifth negative focal power lens which are sequentially arranged from the object side to the image side;
the fourth lens group consists of an eighth positive focal power lens, a sixth negative focal power lens and a ninth positive focal power lens which are arranged in sequence from the object side to the image side;
the fifth lens group is composed of a seventh negative power lens and a tenth positive power lens which are arranged in order from the object side to the image side.
2. The lens barrel as claimed in claim 1, wherein the first negative power lens is a meniscus lens, and a surface thereof facing the object side is a convex surface;
the first positive focal power lens is a biconvex lens;
the second positive focal power lens is a meniscus lens, and one surface of the second positive focal power lens facing the object side is a convex surface;
the second negative focal power lens is a biconcave lens;
the third negative focal power lens is a biconcave lens;
the third positive focal power lens is a meniscus lens, and one surface of the third positive focal power lens facing the object side is a convex surface;
the fourth positive focal power lens is a meniscus lens, and one surface of the fourth positive focal power lens facing the object side is a convex surface;
the fifth positive focal power lens is a biconvex lens;
the fourth negative focal power lens is a biconcave lens;
the sixth positive focal power lens is a biconvex lens;
the seventh positive focal power lens is a meniscus lens, and one surface of the seventh positive focal power lens facing the image side is a convex surface;
the fifth negative focal power lens is a biconcave lens;
the eighth positive focal power lens is a biconvex lens;
the sixth negative focal power lens is a biconcave lens;
the ninth positive focal power lens is a biconvex lens;
the seventh negative power lens is a meniscus lens, and one surface of the seventh negative power lens facing the object side is a convex surface;
the tenth positive power lens is a meniscus lens, and one surface of the tenth positive power lens facing the object side is a convex surface.
3. The lens barrel as claimed in claim 1, wherein the eighth positive power lens is an aspherical double convex lens.
4. The lens barrel according to claim 1, wherein the first negative power lens and the first positive power lens constitute a cemented lens group;
the fourth negative focal power lens and the sixth positive focal power lens form a cemented lens group;
the seventh positive focal power lens and the fifth negative focal power lens form a cemented lens group;
and the sixth negative focal power lens and the ninth positive focal power lens form a cemented lens group.
5. The lens barrel as claimed in claim 1, wherein a center radius of curvature R8 of the image side surface of the second negative power lens and a center radius of curvature R9 of the object side surface of the third negative power lens satisfy:
6. the lens barrel according to claim 1, wherein a distance BFL from an image plane surface of the tenth positive power lens to the image plane and a distance TL from an object plane side of the first negative power lens to an image plane surface of the tenth positive power lens satisfy: TL/BFL is less than or equal to 4.5.
7. The lens barrel according to claim 1, wherein f23 of the focal length of the third positive power lens, f34 of the focal length of the sixth positive power lens, and f41 of the focal length of the eighth positive power lens satisfy: f23 is less than or equal to 46; f34 is less than or equal to 34; f41 is less than or equal to 51.
8. The lens barrel according to claim 1, wherein an abbe number Vd11 of a glass material of the first negative power lens, an abbe number Vd22 of a glass material of the third negative power lens, and an abbe number Vd51 of a glass material of the seventh negative power lens satisfy: vd11 is less than or equal to 33; vd22 is less than or equal to 75; vd51 is less than or equal to 53.
9. The lens barrel according to claim 1, wherein a refractive index Nd31 of a glass material of the fourth positive power lens, a refractive index Nd33 of a glass material of the fourth negative power lens, a refractive index Nd43 of a glass material of the ninth positive power lens, and a refractive index Nd52 of a glass material of the tenth positive power lens satisfy: nd31 is less than or equal to 1.73; nd33 is more than or equal to 1.62; nd43 is more than or equal to 1.85; nd52 is more than or equal to 1.68.
10. The lens barrel according to claim 1, wherein the light splitting means includes two prisms, and a joining surface of the two prisms is provided with a film layer having a light splitting function.
Technical Field
The invention relates to the technical field of optical imaging, in particular to a lens.
Background
Owing to the rapid development of the security monitoring field in recent years, the optical lens is increasingly applied to the security field, and particularly in the fields of intelligent buildings, intelligent transportation and the like, the pixel requirement of the optical imaging lens is higher and higher. More and more enterprises are beginning to invest more research in ultra high definition, and are expecting to develop products with higher pixels and smaller sizes. With the rapid development of the security field, the usage amount of the zoom lens rises year by year, and the requirements on the optical performance and the product stability of the zoom lens are higher and higher. However, the following problems still exist in the existing optical imaging lens: 1. the existing zoom lens has small imaging target surface size and low resolution of acquired images. 2. The aperture of the zoom lens is small, and under the condition of low illumination, the image of a camera is dark, so that the adaptability of the product is reduced. 3. The number of lenses is used more, and the lens size is great for whole camera can't realize miniaturized design. 4. The lens resolution is not high, and the imaging quality is general. 5. Most lenses do not have infrared confocal function.
Therefore, there is a need for an optical zoom lens with high resolution and high target surface, large aperture, small size and low cost.
Disclosure of Invention
The embodiment of the invention provides a lens, which is used for providing a high-resolution lens with a large target surface, a large aperture and low cost.
The embodiment of the invention provides a lens, which is composed of a first lens group, a second lens group, an aperture diaphragm, a third lens group, a fourth lens group, a fifth lens group and a light splitting device which are sequentially arranged from an object side to an image side; each light emitting side of the light splitting device sequentially comprises an optical filter and an image plane;
the positions of the first lens group, the third lens group and the fifth 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:
wherein f is2Is the focal length of the second lens group, f4Is the focal length of the fourth lens group, fwIs the focal length of the lens in the short focus state, fTFor the focal length, FOV, of the lens in tele statewFor the field angle, FOV, of the lens in short focusTThe field angle of the lens in a long-focus state is defined;
the first lens group consists of a first negative focal power lens, a first positive focal power lens and a second positive focal power lens which are arranged in sequence from the object side to the image side;
the second lens group consists of a second negative focal power lens, a third negative focal power lens and a third positive focal power lens which are arranged in sequence from the object side to the image side;
the third lens group consists of a fourth positive focal power lens, a fifth positive focal power lens, a fourth negative focal power lens, a sixth positive focal power lens, a seventh positive focal power lens and a fifth negative focal power lens which are sequentially arranged from the object side to the image side;
the fourth lens group consists of an eighth positive focal power lens, a sixth negative focal power lens and a ninth positive focal power lens which are arranged in sequence from the object side to the image side;
the fifth lens group is composed of a seventh negative power lens and a tenth positive power lens which are arranged in order from the object side to the image side.
Further, the first negative power lens is a meniscus lens, and one surface of the meniscus lens facing the object side is a convex surface;
the first positive focal power lens is a biconvex lens;
the second positive focal power lens is a meniscus lens, and one surface of the second positive focal power lens facing the object side is a convex surface;
the second negative focal power lens is a biconcave lens;
the third negative focal power lens is a biconcave lens;
the third positive focal power lens is a meniscus lens, and one surface of the third positive focal power lens facing the object side is a convex surface;
the fourth positive focal power lens is a meniscus lens, and one surface of the fourth positive focal power lens facing the object side is a convex surface;
the fifth positive focal power lens is a biconvex lens;
the fourth negative focal power lens is a biconcave lens;
the sixth positive focal power lens is a biconvex lens;
the seventh positive focal power lens is a meniscus lens, and one surface of the seventh positive focal power lens facing the image side is a convex surface;
the fifth negative focal power lens is a biconcave lens;
the eighth positive focal power lens is a biconvex lens;
the sixth negative focal power lens is a biconcave lens;
the ninth positive focal power lens is a biconvex lens;
the seventh negative power lens is a meniscus lens, and one surface of the seventh negative power lens facing the object side is a convex surface;
the tenth positive power lens is a meniscus lens, and one surface of the tenth positive power lens facing the object side is a convex surface.
Further, the eighth positive power lens is an aspherical double convex lens.
Further, the first negative power lens and the first positive power lens constitute a cemented lens group;
the fourth negative focal power lens and the sixth positive focal power lens form a cemented lens group;
the seventh positive focal power lens and the fifth negative focal power lens form a cemented lens group;
and the sixth negative focal power lens and the ninth positive focal power lens form a cemented lens group.
Further, the central curvature radius R8 of the image side surface of the second negative power lens and the central curvature radius R9 of the object side surface of the third negative power lens satisfy:
further, a distance BFL from an image side surface of the tenth positive power lens to an image surface and a distance TL from an object surface side of the first negative power lens to the image side surface of the tenth positive power lens satisfy: TL/BFL is less than or equal to 4.5.
Further, f23 of the focal length of the third positive power lens, f34 of the focal length of the sixth positive power lens, and f41 of the focal length of the eighth positive power lens satisfy: f23 is less than or equal to 46; f34 is less than or equal to 34; f41 is less than or equal to 51.
Further, the abbe number Vd11 of the glass material of the first negative power lens, the abbe number Vd22 of the glass material of the third negative power lens, and the abbe number Vd51 of the glass material of the seventh negative power lens satisfy: vd11 is less than or equal to 33; vd22 is less than or equal to 75; vd51 is less than or equal to 53.
Further, a refractive index Nd31 of a glass material of the fourth positive power lens, a refractive index Nd33 of a glass material of the fourth negative power lens, a refractive index Nd43 of a glass material of the ninth positive power lens, and a refractive index Nd52 of a glass material of the tenth positive power lens satisfy: nd31 is less than or equal to 1.73; nd33 is more than or equal to 1.62; nd43 is more than or equal to 1.85; nd52 is more than or equal to 1.68.
Further, the light splitting device comprises two prisms, and the joint surfaces of the two prisms are provided with film layers with light splitting functions.
The embodiment of the invention provides a lens, which is composed of a first lens group, a second lens group, an aperture diaphragm, a third lens group, a fourth lens group, a fifth lens group and a light splitting device which are sequentially arranged from an object side to an image side; each light emitting side of the light splitting device sequentially comprises an optical filter and an image plane; the positions of the first lens group, the third lens group and the fifth 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: wherein f is2Is the focal length of the second lens group, f4Is the focal length of the fourth lens group, fwIs the lens atFocal length in short focal state, fTFor the focal length, FOV, of the lens in tele statewFor the field angle, FOV, of the lens in short focusTThe angle of view of the lens in the telephoto state. Since in the embodiment of the present invention, five lens groups are arranged in the lens in order from the object side to the image side in a specific order, the five lens groups include 17 lenses of specific power, the positions of the first lens group, the third lens group and the fifth 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 satisfy: the high-resolution lens with the large target surface, the large aperture and the low cost is realized.
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 in a short focus state according to an embodiment of the present invention;
fig. 2 is a schematic view of a lens in a telephoto state according to an embodiment of the present invention;
fig. 3 is a graph of an optical transfer function (MTF) in a normal temperature state of a visible light band in a short focus state of the lens according to the embodiment of the present invention;
fig. 4 is a field curvature and distortion diagram of the lens in the short focus state in the visible light band according to the embodiment of the present invention;
fig. 5 is a transverse light fan diagram of the lens in the short focus state in the visible light band according to the embodiment of the present invention;
fig. 6 is a dot-column diagram of a visible light band in a short-focus state of the lens according to the embodiment of the present invention;
fig. 7 is a graph of an optical transfer function (MTF) in a normal temperature state of a visible light band in a telephoto state according to an embodiment of the present invention;
FIG. 8 is a diagram illustrating curvature of field and distortion in the visible light band for a long focus lens according to an embodiment of the present invention;
FIG. 9 is a diagram of the lateral light fan in the visible band in the telephoto state of the lens according to the embodiment of the present invention;
fig. 10 is a dot-column diagram of the lens in the telephoto state in the visible light band according to the embodiment of the present invention.
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, which includes, in order from an object side to an image side, a first lens group G1, a second lens group G2, an aperture stop P, a third lens group G3, a fourth lens group G4, a fifth lens group G5, and a light splitting device Q; each light emitting side of the light splitting device Q sequentially comprises an optical filter M and an image plane N;
the positions of the first lens group G1, the third lens group G3 and the fifth lens group G5 are fixed, and the second lens group G2 and the fourth lens group G4 can move along the optical axis;
the lens group satisfies the following conditions:
wherein f2 isFocal length of the second lens group, f4 is focal length of the fourth lens group, fwIs the focal length of the lens in the short focus state, fTFor the focal length, FOV, of the lens in tele statewFor the field angle, FOV, of the lens in short focusTThe field angle of the lens in a long-focus state is defined;
the first lens group G1 is composed of a first negative power lens L11, a first positive power lens L12 and a second positive power lens L13 which are arranged in order from the object side to the image side;
the second lens group G2 is composed of a second negative power lens L21, a third negative power lens L22 and a third positive power lens L23 which are arranged in order from the object side to the image side;
the third lens group G3 is composed of a fourth positive power lens L31, a fifth positive power lens L32, a fourth negative power lens L33, a sixth positive power lens L34, a seventh positive power lens L35 and a fifth negative power lens L36 which are arranged in order from the object side to the image side;
the fourth lens group G4 is composed of an eighth positive power lens L41, a sixth negative power lens L42, and a ninth positive power lens L43 arranged in this order from the object side to the image side;
the fifth lens group G5 is composed of a seventh negative power lens L51 and a tenth positive power lens L52 arranged in this order from the object side to the image side.
The lens barrel can realize zooming by changing the positions of lens groups, wherein the positions of the first lens group, the third lens group and the fifth lens group are fixed, and the second lens group and the fourth lens group can move along the optical axis to realize zooming. I.e. the second lens group can be moved in a position between the first lens group and the stop. The second lens group may be close to the first lens group, far from the stop; or 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 fifth lens group. The fourth lens group may be close to the third lens group, distant from the fifth lens group; it may be further from the third lens group and closer to the fifth lens group. The second lens group moves in the optical axis direction to perform zooming, and is called a zoom group or a magnification-varying group. In addition, compensation is performed by moving the fourth lens group in the direction of the optical axis so that the image point variation caused by the second lens group at the image plane is zero, thereby realizing zooming without moving the image plane, 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.
The light splitting device comprises two prisms, and film layers with light splitting functions are arranged on the joint surfaces of the two prisms.
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.
Since in the embodiment of the present invention, five lens groups are arranged in the lens in order from the object side to the image side in a specific order, the five lens groups include 17 lenses of specific power, the positions of the first lens group, the third lens group and the fifth 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 satisfy: the high-resolution lens with the large target surface, the large aperture and the low cost is realized.
In order to further improve the imaging quality of the lens barrel, in the embodiment of the invention, the first negative power lens is a meniscus lens, and one surface of the first negative power lens facing the object side is a convex surface;
the first positive focal power lens is a biconvex lens;
the second positive focal power lens is a meniscus lens, and one surface of the second positive focal power lens facing the object side is a convex surface;
the second negative focal power lens is a biconcave lens;
the third negative focal power lens is a biconcave lens;
the third positive focal power lens is a meniscus lens, and one surface of the third positive focal power lens facing the object side is a convex surface;
the fourth positive focal power lens is a meniscus lens, and one surface of the fourth positive focal power lens facing the object side is a convex surface;
the fifth positive focal power lens is a biconvex lens;
the fourth negative focal power lens is a biconcave lens;
the sixth positive focal power lens is a biconvex lens;
the seventh positive focal power lens is a meniscus lens, and one surface of the seventh positive focal power lens facing the image side is a convex surface;
the fifth negative focal power lens is a biconcave lens;
the eighth positive focal power lens is a biconvex lens;
the sixth negative focal power lens is a biconcave lens;
the ninth positive focal power lens is a biconvex lens;
the seventh negative power lens is a meniscus lens, and one surface of the seventh negative power lens facing the object side is a convex surface;
the tenth positive power lens is a meniscus lens, and one surface of the tenth positive power lens facing the object side is a convex surface.
In order to make the lens processing performance better, the eighth positive power lens in the embodiment of the present invention is an aspheric double convex lens.
In order to further enable the system to be compact, in the embodiment of the present invention, the first negative power lens and the first positive power lens constitute a cemented lens group;
the fourth negative focal power lens and the sixth positive focal power lens form a cemented lens group;
the seventh positive focal power lens and the fifth negative focal power lens form a cemented lens group;
and the sixth negative focal power lens and the ninth positive focal power lens form a cemented lens group.
To further improve the lensIn the embodiment of the present invention, the central curvature radius R8 of the image-side surface of the second negative power lens and the central curvature radius R9 of the object-side surface of the third negative power lens satisfy:
in order to further enable the system to be compact, in the embodiment of the present invention, a distance BFL from the image-side surface of the tenth positive power lens to the image plane and a distance TL from the object-side surface of the first negative power lens to the image-side surface of the tenth positive power lens satisfy: TL/BFL is less than or equal to 4.5.
In order to further improve the imaging quality of the lens, in the embodiment of the present invention, f23 of the focal length of the third positive power lens, f34 of the focal length of the sixth positive power lens, and f41 of the focal length of the eighth positive power lens satisfy: f23 is less than or equal to 46; f34 is less than or equal to 34; f41 is less than or equal to 51.
In the embodiment of the present invention, in order to form an image clearly in a wide temperature range of the lens, in the embodiment of the present invention, the abbe number Vd11 of the glass material of the first negative power lens, the abbe number Vd22 of the glass material of the third negative power lens, and the abbe number Vd51 of the glass material of the seventh negative power lens satisfy: vd11 is less than or equal to 33; vd22 is less than or equal to 75; vd51 is less than or equal to 53. In addition, the following are satisfied: vd11 is less than or equal to 33; vd22 is less than or equal to 75; vd51 ≦ 53 may also reduce the color difference of the image, thereby improving the imaging quality.
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 Nd31 of the glass material of the fourth positive power lens, the refractive index Nd33 of the glass material of the fourth negative power lens, the refractive index Nd43 of the glass material of the ninth positive power lens and the refractive index Nd52 of the glass material of the tenth positive power lens satisfy the following conditions: nd31 is less than or equal to 1.73; nd33 is more than or equal to 1.62; nd43 is more than or equal to 1.85; nd52 is more than or equal to 1.68. And, satisfies: nd31 is less than or equal to 1.73; nd33 is more than or equal to 1.62; nd43 is more than or equal to 1.85; the Nd52 is more than or equal to 1.68, so that the spherical aberration can be reduced, and the imaging quality is improved.
The optical performance of the lens provided by the embodiment of the invention is as follows: the imaging maximum supports the sensor of 1/1.2 inch of the target surface, and the total mechanical length of the lens does not exceed 113 mm; the MTF value of the whole field of view reaches more than 0.6 under the condition of 100 lp/mm; the lens has fewer lenses, adopts aspheric lenses, and has good processability and lower cost control; the aperture is large, the F number is 1.6, and the device is particularly suitable for monitoring requirements under low illumination conditions.
The following exemplifies the lens parameters provided by the embodiment of the present invention.
Example 1:
in a specific implementation process, the curvature radius R, the center thickness Tc, the refractive index Nd, the Abbe constant Vd and the conic coefficient k of each lens of the lens meet the conditions listed in Table 1:
TABLE 1
Note that, the mirror numbers in table 1 are the numbers of the left to right lenses in the schematic view of the lens structure shown in fig. 1;
the eighth positive power lens L41 in the embodiment of the present invention is an aspheric lens.
The aspheric conic coefficients can be defined by the following aspheric equation, but are not limited to the following representation:
wherein Z is the axial rise of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitting sphere, and the numerical value is the reciprocal of the curvature radius; k is a fitting cone coefficient; A-F are coefficients of 4 th, 6 th, 8 th, 10 th, 12 th and 14 th order terms of the aspheric polynomial.
TABLE 2
Wherein, the variable thickness data is as shown in the parameter table 3:
focal length
D5
D11
D22
D27
15.6mm
1.87
31.10
4.97
0.10
56mm
29.81
3.16
4.59
0.48
TABLE 3
The lens provided by the embodiment has the following optical technical indexes:
the total optical length TTL is less than or equal to 113 mm;
focal length f of the lens: 15.6(W) mm-56(T) mm;
angle of view of lens: 48.4 ° (W) -12.8 ° (T);
optical distortion of the lens: -8.0% (W) to 2% (T);
aperture fno of lens system: 1.6(W) -1.9 (T);
size of a lens image plane: 1/1.2';
note: w represents short focus, and T represents long focus.
Example 2:
in a specific implementation process, the curvature radius R, the center thickness Tc, the refractive index Nd, the abbe constant Vd and the conic coefficient k of each lens of the lens barrel satisfy the conditions listed in table 4:
TABLE 4
Note that, the mirror numbers in table 4 are the numbers of the left to right lenses in the schematic view of the lens structure shown in fig. 1;
the eighth positive power lens L41 in the embodiment of the present invention is an aspheric lens.
The aspheric conic coefficients can be defined by the following aspheric equation, but are not limited to the following representation:
wherein Z is the axial rise of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitting sphere, and the numerical value is the reciprocal of the curvature radius; k is a fitting cone coefficient; A-F are coefficients of 4 th, 6 th, 8 th, 10 th, 12 th and 14 th order terms of the aspheric polynomial.
TABLE 5
Wherein, the variable thickness data is as shown in the parameter table 6:
TABLE 6
The lens provided by the embodiment has the following optical technical indexes:
the total optical length TTL is less than or equal to 113 mm;
focal length f of the lens: 14.5(W) mm-60(T) mm;
angle of view of lens: 52.2 ° (W) -11.5 ° (T);
optical distortion of the lens: -8.2% (W) to 2.2% (T);
aperture fno of lens system: 1.6(W) -1.9 (T);
size of a lens image plane: 1/1.2';
note: w represents short focus, and T represents long focus.
The lens provided by the embodiment is further described below by performing a detailed optical system analysis on the embodiment.
The optical transfer function is used for evaluating the imaging quality of an optical system in a more accurate, visual and common mode, and the higher and smoother curve of the optical transfer function indicates that the imaging quality of the system is better, and aberration is well corrected.
As shown in fig. 1, it is a schematic view of a lens in a short focus state;
as shown in fig. 2, the lens is in a long focus state;
as shown in fig. 3, it is a graph of optical transfer function (MTF) in a short focus state of the lens at a normal temperature state of the visible light band;
as shown in fig. 4, the field curvature and distortion diagram in the visible light band in the short focus state of the lens;
as shown in fig. 5, it is a transverse light fan diagram in the visible light band in the short focus state of the lens;
as shown in fig. 6, it is a dot-sequence diagram of the visible light band in the short focus state of the lens;
as shown in fig. 7, it is a graph of optical transfer function (MTF) in a state of a long focus lens at a normal temperature in a visible light band;
FIG. 8 shows the field curvature and distortion in the visible light band in the telephoto state of the lens;
FIG. 9 is a diagram of the lateral light fan in the visible band in the telephoto state of the lens;
as shown in fig. 10, the diagram is a dot-column diagram of the visible light band in the telephoto state of the lens.
As can be seen from fig. 3, the optical transfer function (MTF) curve in the short focus state of the lens is smooth and concentrated in the visible light portion at normal temperature state, and the average MTF value of the full field of view (half-image height Y' is 6.4mm) is more than 0.6; therefore, the lens provided by the embodiment can meet higher imaging requirements in a short-focus state.
As can be seen from fig. 7, the optical transfer function (MTF) curve in the normal temperature state in the visible light portion in the telephoto state is relatively smooth and concentrated, and the average MTF value in the full field of view (half-image height Y' is 6.4mm) is 0.6 or more; therefore, the lens provided by the embodiment can meet higher imaging requirements in a long-focus state.
As can be seen from fig. 4 and 8, the curvature of field in the short focus state of the lens is controlled within ± 0.05mm, and the curvature of field in the long focus state is controlled within ± 0.1 mm. The inner curvature of field is also called as "curvature of field". When the lens has field curvature, the intersection point of the whole light beam is not overlapped with an ideal image point, and although a clear image point can be obtained at each specific point, the whole image plane is a curved surface. T represents the meridional field curvature, and S represents the sagittal field curvature. The field curvature curve shows the distance of the current focal plane or image plane to the paraxial focal plane as a function of field coordinates, and the meridional field curvature data is the distance from the currently determined focal plane to the paraxial focal plane measured along the Z axis and measured in the meridional (YZ plane). Sagittal curvature of field data measures distances measured in a plane perpendicular to the meridian plane, the base line in the schematic is on the optical axis, the top of the curve represents the maximum field of view (angle or height), and no units are set on the vertical axis, since the curve is always normalized by the maximum radial field of view.
As can be seen from fig. 4 and 8, the distortion control is good in the short focus state of the lens, and is within-8.0%, and the distortion control is good in the long focus state, and is within + 2.0%. Fig. 2 coincides in fig. 2 with reference to curves of a plurality of wavelengths (0.436mm, 0.486mm, 0.546mm, 0.587mm, and 0.656 mm). Generally, lens distortion is a general term of intrinsic perspective distortion of an optical lens, that is, distortion caused by perspective, which is very unfavorable for the imaging quality of a photograph, and after all, the purpose of photography is to reproduce rather than exaggerate, but because the distortion is intrinsic characteristics of the lens (converging light rays of a convex lens and diverging light rays of a concave lens), the distortion cannot be eliminated, and only can be improved. As can be seen from fig. 8, the distortion of the zoom lens provided by the embodiment of the present invention is-8.0% in the short focus state and is only + 2.0% in the long focus state; the distortion is set to balance the focal length, the field angle and the size of the target surface of the corresponding camera, and the deformation caused by the distortion can be corrected through post image processing.
As can be seen from fig. 5 and 9, the curves in the sector diagrams are more concentrated, and the spherical aberration and the chromatic dispersion of the lens are better controlled.
As can be seen from fig. 6 and 10, the lens has a small and relatively concentrated light spot radius, and the corresponding aberration and coma are also good.
In summary, the embodiment of the invention provides an optical zoom lens which has a large target surface, a large aperture, low cost and infrared confocal imaging high definition. The 17 optical lenses with specific structural shapes are adopted and arranged in sequence from the object side to the image side according to a specific sequence, and the lens can realize better distortion control and excellent imaging characteristics through distribution and combination of specific optical powers of the optical lenses.
The embodiment of the invention provides a lens, which is composed of a first lens group, a second lens group, an aperture diaphragm, a third lens group, a fourth lens group, a fifth lens group and a light splitting device which are sequentially arranged from an object side to an image side; the light splittingEach light emergent side of the device sequentially comprises an optical filter and an image plane; the positions of the first lens group, the third lens group and the fifth 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: wherein f is2Is the focal length of the second lens group, f4Is the focal length of the fourth lens group, fwIs the focal length of the lens in the short focus state, fTFor the focal length, FOV, of the lens in tele statewFor the field angle, FOV, of the lens in short focusTThe angle of view of the lens in the telephoto state. Since in the embodiment of the present invention, five lens groups are arranged in the lens in order from the object side to the image side in a specific order, the five lens groups include 17 lenses of specific power, the positions of the first lens group, the third lens group and the fifth 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 satisfy: the high-resolution lens with the large target surface, the large aperture and the low cost is realized.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.