Zoom lens and imaging device

Abstract

The invention discloses a zoom lens and an imaging device, comprising a lens body, wherein the lens body comprises a lens barrel and a first lens group with positive focal power, a second lens group with negative focal power, an aperture, a third lens group with positive focal power, a fourth lens group with positive focal power and a photosensitive chip which are sequentially arranged in the lens barrel from front to back. The second lens group and the fourth lens group are movably arranged in the front-rear direction relative to the lens barrel, respectively. The second lens group moves along the optical axis to enable the zoom lens to zoom, and the fourth lens group moves along the optical axis to enable the zoom lens to focus. Through the reasonable arrangement of the four lens groups and the conditional restriction of the focal length of the zoom lens at the wide-angle end and the focal length ratio of each lens group, the zoom lens has the effects of small size, low cost, large magnification and large aperture.

Description

Technical Field

[0001] The present invention relates to the technical field of optical system design, and in particular to a zoom lens and an imaging device. Background Art

[0002] With the development of society, people's awareness of safety precautions has been continuously improved, the security monitoring industry has also been rapidly developed, and the role of monitoring has become increasingly important. Zoom lenses were actually designed and used in the last century. With the development of lens design technology, the application occasions of zoom lenses have gradually increased. Nowadays, zoom lenses have been widely used in civilian products, security monitoring and other fields. However, since the imaging quality of zoom lenses is worse than that of ordinary fixed focal length lenses, the popularity of zoom lenses is not high. Moreover, most of the zoom lenses on the market now have a small target size, resulting in low resolution of the collected images, general shooting effects, and low value of the pictures. Moreover, most of the zoom lenses on the market now have a small aperture, resulting in less light transmission from the lens, and the images obtained in low-light scenes are darker, making it difficult to ensure image quality. As security moves towards high definition and miniaturization, lenses need to achieve higher performance and smaller size. Summary of the invention

[0003] The main purpose of the present invention is to provide a zoom lens, aiming to improve the technical problems of small zoom magnification and small aperture of zoom lenses in the prior art.

[0004] To achieve the above object, the present invention provides a zoom lens, comprising a lens body, wherein the direction from the object side to the image side along the optical axis of the lens body is from front to back;

[0005] The lens body comprises a lens barrel, and a first lens group with positive focal power, a second lens group with negative focal power, an aperture, a third lens group with positive focal power, a fourth lens group with positive focal power and a photosensitive chip which are sequentially arranged in the lens barrel from front to back, the first lens group and the third lens group are fixedly arranged, the second lens group and the fourth lens group are movably arranged in the front-rear direction relative to the lens barrel, the second lens group moves along the optical axis to enable the zoom lens to zoom, and the fourth lens group moves along the optical axis to enable the zoom lens to focus;

[0006] The zoom lens satisfies the following conditions: 0.02<fw / f1<0.2, and -1.74<fw / f2<-0.19, and 0.05<fw / f3<0.45, and 0.11<fw / f4<0.95;

[0007] Wherein, fw is the focal length of the zoom lens at the wide-angle end, f1 is the focal length of the first lens group, 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;

[0008] The first lens group includes, arranged from front to back, a first lens with positive power, a second lens with negative power, a third lens with positive power, a fourth lens with positive power, a fifth lens with positive power, and a sixth lens with negative power;

[0009] The first lens group and the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens satisfy the following conditions: 0.03<f1 / f11<0.27, and -1.89<f1 / f12<-0.21, and 0.2<f1 / f13<1.84, and 0.07<f1 / f14<0.65, and 0.09<f1 / f15<0.79, and -4.03<f1 / f16<-0.45;

[0010] Wherein, f1 is the focal length of the first lens group, f11 is the focal length of the first lens, f12 is the focal length of the second lens, f13 is the focal length of the third lens, f14 is the focal length of the fourth lens, f15 is the focal length of the fifth lens, and f16 is the focal length of the sixth lens;

[0011] The second lens group includes, arranged from front to back, a seventh lens with negative optical power, an eighth lens with negative optical power, a ninth lens with negative optical power, and a tenth lens with positive optical power, wherein the seventh lens and the eighth lens are aspherical lenses;

[0012] The second lens group and the seventh lens, the eighth lens, the ninth lens and the tenth lens satisfy the following relationship: 0.07<f2 / f21<0.64, and 0.18<f2 / f22<1.65, and 0.06<f2 / f23<0.57, and -0.11<f2 / f24<-1.03;

[0013] Wherein, f2 is the focal length of the second lens group, f21 is the focal length of the seventh lens, f22 is the focal length of the eighth lens, f23 is the focal length of the ninth lens, and f24 is the focal length of the tenth lens;

[0014] The third lens group includes, arranged from front to back, an eleventh lens with positive power, a twelfth lens with positive power, a thirteenth lens with negative power, a fourteenth lens with positive power, and a fifteenth lens with negative power, wherein the eleventh lens is an aspherical lens;

[0015] The third lens group and the eleventh lens, the twelfth lens, the thirteenth lens, the fourteenth lens and the fifteenth lens satisfy the following relationship: 0.38<f3 / f31<3.38, and 0.29<f3 / f32<2.62, and -1.18<f3 / f33<-0.13, and 0<f3 / f34<0.07, and -5.9<f3 / f35<-0.66;

[0016] Wherein, f3 is the focal length of the third lens group, f31 is the focal length of the eleventh lens, f32 is the focal length of the twelfth lens, f33 is the focal length of the thirteenth lens, f34 is the focal length of the fourteenth lens, and f35 is the focal length of the fifteenth lens;

[0017] The fourth lens group includes a sixteenth lens with positive power, a seventeenth lens with negative power and an eighteenth lens with positive power, which are arranged in sequence from front to back, wherein the eighteenth lens is an aspherical lens;

[0018] The fourth lens group and the sixteenth lens, the seventeenth lens and the eighteenth lens satisfy the following relationship: 0.13<f4 / f41<1.18, and -2.17<f4 / f42<-0.24, and 0.46<f4 / f43<4.13;

[0019] Among them, f4 is the focal length of the fourth lens group, f41 is the focal length of the sixteenth lens, f42 is the focal length of the seventeenth lens, and f43 is the focal length of the eighteenth lens.

[0020] Optionally, the first lens group includes, arranged from front to back, a first lens with positive power, a second lens with negative power, a third lens with positive power, a fourth lens with positive power, a fifth lens with positive power, and a sixth lens with negative power;

[0021] The first lens group and the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens satisfy the following conditions: 0.03<f1 / f11<0.27, and -1.89<f1 / f12<-0.21, and 0.2<f1 / f13<1.84, and 0.07<f1 / f14<0.65, and 0.09<f1 / f15<0.79, and -4.03<f1 / f16<-0.45;

[0022] Among them, f1 is the focal length of the first lens group, f11 is the focal length of the first lens, f12 is the focal length of the second lens, f13 is the focal length of the third lens, f14 is the focal length of the fourth lens, f15 is the focal length of the fifth lens, and f16 is the focal length of the sixth lens.

[0023] Optionally, the first lens and the second lens constitute a first cemented lens; the fifth lens and the sixth lens constitute a second cemented lens.

[0024] Optionally, the ninth lens and the tenth lens constitute a third cemented lens.

[0025] Optionally, the twelfth lens and the thirteenth lens constitute a fourth cemented lens; the fourteenth lens and the fifteenth lens constitute a fifth cemented lens.

[0026] Optionally, the sixteenth lens and the seventeenth lens constitute a sixth cemented lens.

[0027] The present invention also provides an imaging device, which includes the zoom lens described in the above technical solution.

[0028] In the technical solution provided by the present invention, the lens body includes a lens barrel and a first lens group with positive focal power, a second lens group with negative focal power, an aperture, a third lens group with positive focal power, a fourth lens group with positive focal power and a photosensitive chip which are sequentially arranged in the lens barrel from front to back. The second lens group and the fourth lens group are movably arranged in the front-rear direction relative to the lens barrel, respectively. The second lens group moves along the optical axis to enable the zoom lens to zoom, and the fourth lens group moves along the optical axis to enable the zoom lens to zoom. focus; when the second lens group moves along the optical axis toward the image side, so that the zoom lens is zoomed from the wide-angle end to the telephoto end, the fourth lens group moves and focuses along the optical axis corresponding to the position of the zoom lens group, the imaging wavelength, and the imaging object distance, so that the zoom lens keeps the imaging surface clear during the zooming process. Through the reasonable arrangement of the four lens groups and the conditional restrictions on the ratio of the focal length of the zoom lens at the wide-angle end and the focal length of each lens group, the zoom lens has the effects of small size, low cost, large magnification and large aperture. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0030] Figure 1 A schematic structural diagram of an embodiment of a zoom lens provided by the present invention;

[0031] Figure 2 for Figure 1 Schematic diagram of the MTF curve of a medium zoom lens at the wide-angle end;

[0032] Figure 3 for Figure 1 Schematic diagram of the MTF curve of a medium zoom lens at the telephoto end.

[0033] Description of Figure Numbers:

[0034]

[0035] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] It should be noted that if a directional indication is involved in the embodiment of the present invention, the directional indication is only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0038] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0039] With the development of society, people's awareness of safety precautions has been continuously improved, the security monitoring industry has also been rapidly developed, and the role of monitoring has become increasingly important. Zoom lenses were actually designed and used in the last century. With the development of lens design technology, the application occasions of zoom lenses have gradually increased. Nowadays, zoom lenses have been widely used in civilian products, security monitoring and other fields. However, since the imaging quality of zoom lenses is worse than that of ordinary fixed focal length lenses, the popularity of zoom lenses is not high. Moreover, most of the zoom lenses on the market now have a small target size, resulting in low resolution of the collected images, general shooting effects, and low value of the pictures. Moreover, most of the zoom lenses on the market now have a small aperture, resulting in less light transmission from the lens, and the images obtained in low-light scenes are darker, making it difficult to ensure image quality. As security moves towards high definition and miniaturization, lenses need to achieve higher performance and smaller size.

[0040] In view of this, the main purpose of the present invention is to provide a zoom lens and an imaging device, aiming to improve the technical problems of small zoom lens and small aperture in the prior art. Figures 1 to 3 This is an embodiment of the zoom lens.

[0041] First of all, it can be understood that the optical focal length is equal to the difference between the convergence of the image-side light beam and the convergence of the object-side light beam, and it characterizes the ability of the imaging device to deflect light. The larger the absolute value of the optical focal length, the stronger the ability to bend light, and the smaller the absolute value of the optical focal length, the weaker the ability to bend light. When the optical focal length is a positive number, the refraction of light is convergent; when the optical focal length is a negative number, the refraction of light is divergent. The optical focal length can be used to characterize a certain refractive surface of a lens (i.e., a surface of a lens), can be used to characterize a certain lens, and can also be used to characterize a system formed by multiple lenses (i.e., a lens group).

[0042] The direction of the optical axis of the zoom lens from the object side to the image side is from front to back. It can be understood that the object side faces the subject and the light transmission direction is from the object side to the image side.

[0043] The zoom lens comprises a lens body; the lens body comprises a lens barrel and a first lens group 1 with positive focal power, a second lens group 2 with negative focal power, an aperture 5, a third lens group 3 with positive focal power, a fourth lens group 4 with positive focal power and a photosensitive chip 6 which are sequentially arranged in the lens barrel from front to back, the second lens group 2 and the fourth lens group 4 are respectively movably arranged in the front-rear direction relative to the lens barrel, the second lens group 2 moves along the optical axis to make the zoom lens zoom, and the fourth lens group 4 moves along the optical axis to make the zoom lens zoom. The optical axis moves so that the zoom lens is focused; the zoom lens satisfies the following conditions: 0.02<fw / f1<0.2, and -1.74<fw / f2<-0.19, and 0.05<fw / f3<0.45, and 0.11<fw / f4<0.95; wherein fw is the focal length of the zoom lens at the wide-angle end, f1 is the focal length of the first lens group 1, f2 is the focal length of the second lens group 2, f3 is the focal length of the third lens group 3, and f4 is the focal length of the fourth lens group 4.

[0044] Specifically, in this embodiment, the ratios of the focal length of the zoom lens at the wide-angle end to the focal lengths of each lens group are as follows: fw / f1=1 / 15, fw / f2=-(11 / 19), fw / f3=11 / 74, fw / f4=6 / 19.

[0045] In the technical solution provided by the present invention, when the second lens group 2 moves along the optical axis toward the image side, so that the zoom lens is zoomed from the wide-angle end to the telephoto end, the fourth lens group 4 moves and focuses along the optical axis corresponding to the position of the zoom lens group, the imaging wavelength, and the imaging object distance, so that the zoom lens maintains clear imaging on the imaging surface during the zooming process. Through the reasonable arrangement of the four lens groups and the conditional restrictions on the ratio of the focal length of the zoom lens at the wide-angle end and the focal length of each lens group, the zoom lens has the effects of small size, low cost, large magnification and large aperture.

[0046] Specifically, the first lens group 1 includes, arranged from front to back in sequence, a first lens 11 with positive power, a second lens 12 with negative power, a third lens 13 with positive power, a fourth lens 14 with positive power, a fifth lens 15 with positive power, and a sixth lens 16 with negative power; the first lens group 1 and the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, and the sixth lens 16 meet the following conditions: 0.03<f1 / f11<0.27, and -1.89 <f1 / f12<-0.21, and 0.2<f1 / f13<1.84, and 0.07<f1 / f14<0.65, and 0.09<f1 / f15<0.79, and -4.03<f1 / f16<-0.45; wherein f1 is the focal length of the first lens group 1, f11 is the focal length of the first lens 11, f12 is the focal length of the second lens 12, f13 is the focal length of the third lens 13, f14 is the focal length of the fourth lens 14, f15 is the focal length of the fifth lens 15, and f16 is the focal length of the sixth lens 16.

[0047] More specifically, in this embodiment, the first lens 11 is a convex-concave lens, that is, the object side surface of the first lens 11 is convex, and the image side surface is concave, the second lens 12 is a biconvex lens, the third lens 13 is a convex-concave lens, that is, the object side surface of the third lens 13 is convex, and the image side surface is concave, the fourth lens 14 is a convex-concave lens, that is, the object side surface of the fourth lens 14 is convex, and the image side surface is concave, the fifth lens 15 is a convex-concave lens, that is, the object side surface of the fifth lens 15 is convex, and the image side surface is concave, the sixth lens 16 is a convex-concave lens, that is, the sixth lens The object side surface of 16 is convex, and the image side surface is concave, and the focal length ratios of the first lens group and the focal lengths of each lens therein are specifically as follows: f1 / f11=1 / 11, f1 / f12=-(12 / 19), f1 / f13=19 / 31, f1 / f14=11 / 51, f1 / f15=11 / 42, f1 / f16=-(47 / 35), and the optical powers of the first lens 11 to the sixth lens 16 are: 2291.68, -330.4, 340.54, 967.67, 796.67, -155.37, respectively.

[0048] Furthermore, the first lens 11 and the second lens 12 constitute a first cemented lens with positive focal power and satisfy the following condition: 0.07<f1 / f101<0.66; wherein f1 is the focal length of the first lens group 11, and f101 is the focal length of the first cemented lens; in the present embodiment, the ratio of the focal length of the first lens group and the focal length of the first cemented lens is specifically as follows: f1 / f101=11 / 50.

[0049] Further, the fifth lens 15 and the sixth lens 16 constitute a second cemented lens with negative optical power, and satisfy the following condition: -0.22<f1 / f102<-0.02; wherein f1 is the focal length of the first lens group 11, and f102 is the focal length of the second cemented lens; in the present embodiment, the ratio of the focal length of the first lens group to the focal length of the second cemented lens is specifically as follows: f1 / f102=-(6 / 83).

[0050] Specifically, the second lens group 2 includes a seventh lens 21 with negative optical power, an eighth lens 22 with negative optical power, a ninth lens 23 with negative optical power and a tenth lens 24 with positive optical power, which are arranged in sequence from front to back, wherein the seventh lens 21 and the eighth lens 22 are aspherical lenses; the second lens group 2 and the seventh lens 21, the eighth lens 22, the ninth lens 23 and the tenth lens 24 satisfy the following relationship: 0.07<f2 / f21<0.64, and 0.18<f2 / f22<1.65, and 0.06<f2 / f23<0.57, and -0.11<f2 / f24<-1.03; wherein f2 is the focal length of the second lens group 2, f21 is the focal length of the seventh lens 21, f22 is the focal length of the eighth lens 22, f23 is the focal length of the ninth lens 23, and f24 is the focal length of the tenth lens 24.

[0051] More specifically, in this embodiment, the seventh lens 21 is a convex-concave lens, that is, the object-side surface of the seventh lens 21 is convex, and the image-side surface is concave; the eighth lens 22 is a convex-concave lens, that is, the object-side surface of the seventh lens 21 is convex, and the image-side surface is concave; the ninth lens 23 is a biconcave lens; the tenth lens 24 is a convex lens, that is, the object-side surface of the tenth lens 24 is convex, and the image-side surface is flat; and the ratio of the focal length of the second lens group to the focal length of each lens therein is as follows: f2 / f21=3 / 14, f2 / f22=17 / 31, f2 / f23=4 / 21, f2 / f24=-(12 / 35); and the optical powers of the seventh lens 21 to the tenth lens 24 are: -112.94, -44.13, -127.36, 70.62, respectively.

[0052] Further, the ninth lens 23 and the tenth lens 24 constitute a third cemented lens with negative optical power, and satisfy the following condition: 0.06<f2 / f201<0.57, wherein f2 is the focal length of the second lens group 2, and f201 is the focal length of the third cemented lens; in this embodiment, the ratio of the focal length of the second lens group and the focal length of the third cemented lens is specifically as follows: f2 / f201=4 / 21.

[0053] Specifically, the third lens group 3 includes, from front to back, an eleventh lens 31 with positive power, a twelfth lens 32 with positive power, a thirteenth lens 33 with negative power, a fourteenth lens 34 with positive power, and a fifteenth lens 35 with negative power, wherein the eleventh lens is an aspherical lens; the third lens group 3 and the eleventh lens 31, the twelfth lens 32, the thirteenth lens 33, the fourteenth lens 34, and the fifteenth lens 35 satisfy the following relationship: 0.38<f3 / f31<3.38, and 0.29<f3 / f32<2.62, and -1.18<f3 / f33<-0.13, and 0<f3 / f34<0.07, and -5.9<f3 / f35<-0.66; wherein f3 is the focal length of the third lens group 3, f31 is the focal length of the eleventh lens 31, f32 is the focal length of the twelfth lens 32, f33 is the focal length of the thirteenth lens 33, f34 is the focal length of the fourteenth lens 34, and f35 is the focal length of the fifteenth lens 35.

[0054] More specifically, in this embodiment, the eleventh lens 31 is a biconvex lens, the twelfth lens 32 is a biconvex lens, the thirteenth lens 33 is a concave lens, that is, the object side surface of the thirteenth lens 33 is a concave surface, and the image side surface is a plane, the fourteenth lens 34 is a convex lens, that is, the object side surface of the fourteenth lens 34 is a plane, and the image side surface is a convex surface, the fifteenth lens 35 is a biconcave lens, and the ratio of the focal length of the third lens group to the focal length of each lens therein is as follows: f3 / f31=9 / 8, f3 / f32=62 / 71, f3 / f33=-(37 / 94), f3 / f34=2 / 85, f3 / f35=-(59 / 30), and the optical powers of the eleventh lens 31 to the fifteenth lens 35 are: 83.83, 107.89, -239.33, 3988.81, -47.91 respectively.

[0055] Furthermore, the twelfth lens 32 and the thirteenth lens 33 constitute a fourth cemented lens with positive optical power and satisfy the following condition: 0.29<f3 / 301<2.62, wherein f3 is the focal length of the third lens group 33, and f301 is the focal length of the fourth cemented lens; in the present embodiment, the ratio of the focal length of the third lens group and the focal length of the fourth cemented lens is as follows: f3 / 301=62 / 71.

[0056] Further, the fourteenth lens 34 and the fifteenth lens 35 constitute a fifth cemented lens with negative optical power and satisfy the following condition: -5.9<f3 / f302<-0.66, wherein f3 is the focal length of the third lens group 33, and f302 is the focal length of the fifth cemented lens; in this embodiment, the ratio of the focal length of the third lens group and the focal length of the fifth cemented lens is as follows: f3 / f302=-(59 / 30).

[0057] Specifically, the fourth lens group 4 includes a sixteenth lens 41 with positive power, a seventeenth lens 42 with negative power and an eighteenth lens 43 with positive power, which are arranged in sequence from front to back, wherein the eighteenth lens is an aspherical lens; the fourth lens group 4 and the sixteenth lens 41, the seventeenth lens 42 and the eighteenth lens 43 satisfy the following relationship: 0.13<f4 / f41<1.18, and -2.17<f4 / f42<-0.24, and 0.46<f4 / f43<4.13; wherein f4 is the focal length of the fourth lens group 4, f41 is the focal length of the sixteenth lens 41, f42 is the focal length of the seventeenth lens 42, and f43 is the focal length of the eighteenth lens 43.

[0058] More specifically, in this embodiment, the sixteenth lens 41 is a biconvex lens, the seventeenth lens 42 is a concave lens, that is, the object side surface of the seventeenth lens 42 is a concave surface, and the image side surface is a plane, the eighteenth lens 43 is a biconvex lens, and the ratio of the focal length of the fourth lens group to the focal length of each lens therein is specifically as follows: f4 / f41=35 / 89, f4 / f42=-(13 / 18), f4 / f43=84 / 61, and the optical powers of the sixteenth lens 41 to the eighteenth lens 43 are 112.92, -61.48, and 32.24, respectively.

[0059] Further, the sixteenth lens 41 and the seventeenth lens 42 constitute a sixth cemented lens with negative optical power, and satisfy the following condition: -1.18<f4 / f401<-0.13, wherein f4 is the focal length of the fourth lens group 44, and f401 is the focal length of the sixth cemented lens; in the present embodiment, the ratio of the focal length of the fourth lens group and the focal length of the sixth cemented lens is as follows: f4 / f401=-(35 / 89).

[0060] Specifically, the zoom lens further includes an aperture 5, which is located between the second lens group 22 and the third lens group 3. In this embodiment, the aperture 5 is an adjustable aperture 5, which can perform corresponding aperture scaling measures as the ambient light intensity changes. The aperture 5 is used to limit the light beam to further improve the imaging quality of the zoom lens. In this embodiment, the zoom lens satisfies the following conditions: 0.14<L / TTL<1.25; wherein L is the distance from the aperture 5 to the imaging surface of the zoom lens on the optical axis, and TTL is the total optical length of the zoom lens. In this embodiment, specifically L / TTL=5 / 12.

[0061] Specifically, the zoom lens further includes a filter, and the filter is located between the eighteenth lens 43 and the photosensitive chip 6. The filter is used to filter out light of unnecessary wavelengths and stray light, thereby improving imaging quality.

[0062] Furthermore, the zoom lens may further include a protective glass, which is disposed between the filter and the photosensitive chip 6 to prevent internal components (eg, chip) of the zoom lens from being damaged.

[0063] Specifically, in this embodiment, the zoom lens satisfies the following condition: 0.09<øL11 / TTL<0.83; wherein øL11 is the effective clear aperture of the first lens 11, and TTL is the total optical length of the zoom lens, which is specifically øL11 / TTL=18 / 65 in this embodiment.

[0064] Specifically, in this embodiment, the zoom lens satisfies the following condition: 0.14<ΔZW-T / TTL<1.22; wherein ΔZW-T is the relative displacement of the second lens group 2 when the zoom lens is at the wide-angle end position and when the zoom lens is at the telephoto end position, and TTL is the total optical length of the zoom lens. In this embodiment, specifically ΔZW-T / TTL=37 / 91.

[0065] Based on the above, the seventh lens 21, the eighth lens 22, the eleventh lens 31, and the eighteenth lens 43 are all aspherical lenses. It can be understood that the characteristics of aspherical lenses are: the curvature changes continuously from the center of the lens to the periphery of the lens. Unlike spherical lenses with a constant curvature from the center of the lens to the periphery of the lens, aspherical lenses have better curvature radius characteristics, and have the advantages of improving distortion aberration and improving astigmatism aberration. After using aspherical lenses, the aberrations occurring during imaging can be eliminated as much as possible, thereby improving the imaging quality of the lens.

[0066] Further, in this embodiment, the aspheric surface shape of the aspheric lens satisfies the following conditions:

[0067]

[0068] In this formula, parameter c is the curvature corresponding to the radius, r is the radial coordinate, and its unit is the same as the lens length unit, k is the coefficient of the conic quadratic curve, when the k coefficient is less than -1, the surface curve is a hyperbola, when the k coefficient is equal to -1, it is a parabola, when the k coefficient is between -1 and 0, it is an ellipse, when it is equal to 0, it is a circle, and when it is greater than 0, it is an oblate circle, α1 to α8 represent the coefficients corresponding to each radial coordinate, respectively. The above parameters can accurately set the shape and size of the front and rear aspheric surfaces of the lens. While ensuring that the lens has good picture requirements, the product weight is light, the driving burden is reduced, and it has a great contribution to reducing the volume of the driving components.

[0069] Specifically, in this embodiment, the parameters of the zoom lens are shown in the following table.

[0070] Table 1 Parameters of each lens of the zoom lens

[0071]

[0072] In this embodiment, the even-order coefficients of each aspherical surface are shown in the following table.

[0073] Table 2 Even-order coefficients of the aspherical lens of the zoom lens

[0074]

[0075] The zoom lens of the present invention has a wide-angle focal length EFL_W = 14 mm, a telephoto focal length EFL_T = 1020 mm; a wide-angle aperture number Fno_W = 3, a telephoto aperture number Fno_T = 11.5; a wide-angle horizontal field angle FOVH_W = 29.7°, a telephoto field angle FOVH_T = 0.4°; a system optical distortion ∈ (-1%, 0.1%); and a total optical length of the optical system (i.e., a distance from the central vertex of the front surface of the first lens to the image plane) TTL = 361 mm.

[0076] The zoom imaging device described in the present invention adopts a "positive, negative, positive, positive" four-group structure, and the system contains 4 glass aspherical surfaces. While achieving a large aperture, small distortion, and a large zoom ratio, the manufacturing cost is fully reduced.

[0077] Although the zoom lens uses an aspherical lens, the focal length is conditionally limited so that temperature changes have little effect on the performance of the lens, the back focus changes very little, and the performance is stable when the indoor environment changes, without the need for refocusing.

[0078] In the zoom lens, as the second lens group and the fourth lens group move forward and backward, the focal length changes. The fourth lens group is used for focusing function. (Take 1 / 1.8" 16:9 CCD as an example) the focal length can change from <14mm at the wide-angle end to >1020mm at the telephoto end. The shooting angle at the wide-angle end (WIDE) is horizontally >29.7°. The optical distortion at the wide-angle end (WIDE) and the telephoto end is within 0.1%, which has the effect of small distortion and large magnification.

[0079] The zoom lens uses an adjustable aperture, and its FNO. reaches 3 at the wide-angle end and 11.5 at the telephoto end. It has extremely high photosensitivity and can still capture clearer images in darker environments.

[0080] The zoom lens has the first lens group as the highest point, the distance between the first lens group and the image plane is fixed, and its height is less than 361 mm (taking a 1 / 1.8" CCD as an example).

[0081] The zoom lens can achieve a resolution higher than 4K (8 million pixels). Taking a 1 / 1.8" sensor as an example, the present invention can achieve a central resolution higher than 300lp / mm and a peripheral 0.7H (70% diagonal position) resolution higher than 1400TVline.

[0082] In addition, the present invention further provides an imaging device, wherein the mobile device includes the zoom lens described in the above technical solution, and the imaging device may be a monitoring lens, which is not limited here.

[0083] The above descriptions are only optional embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A zoom lens, characterized in that: It includes a lens body, and the direction from the object side to the image side along the optical axis of the lens body is from front to back; The lens body comprises a lens barrel, and a first lens group with positive focal power, a second lens group with negative focal power, an aperture, a third lens group with positive focal power, a fourth lens group with positive focal power and a photosensitive chip which are sequentially arranged in the lens barrel from front to back, the first lens group and the third lens group are fixedly arranged, the second lens group and the fourth lens group are movably arranged in the front-rear direction relative to the lens barrel, the second lens group moves along the optical axis to enable the zoom lens to zoom, and the fourth lens group moves along the optical axis to enable the zoom lens to focus; The zoom lens satisfies the following conditions: 0.02<fw / f1<0.2, and -1.74<fw / f2<-0.19, and 0.05<fw / f3<0.45, and 0.11<fw / f4<0.95; Wherein, fw is the focal length of the zoom lens at the wide-angle end, f1 is the focal length of the first lens group, 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 first lens group includes, arranged from front to back, a first lens with positive power, a second lens with negative power, a third lens with positive power, a fourth lens with positive power, a fifth lens with positive power, and a sixth lens with negative power; The first lens group and the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens satisfy the following conditions: 0.03<f1 / f11<0.27, and -1.89<f1 / f12<-0.21, and 0.2<f1 / f13<1.84, and 0.07<f1 / f14<0.65, and 0.09<f1 / f15<0.79, and -4.03<f1 / f16<-0.45; Wherein, f1 is the focal length of the first lens group, f11 is the focal length of the first lens, f12 is the focal length of the second lens, f13 is the focal length of the third lens, f14 is the focal length of the fourth lens, f15 is the focal length of the fifth lens, and f16 is the focal length of the sixth lens; The second lens group includes, arranged from front to back, a seventh lens with negative optical power, an eighth lens with negative optical power, a ninth lens with negative optical power, and a tenth lens with positive optical power, wherein the seventh lens and the eighth lens are aspherical lenses; The second lens group and the seventh lens, the eighth lens, the ninth lens and the tenth lens satisfy the following relationship: 0.07<f2 / f21<0.64, and 0.18<f2 / f22<1.65, and 0.06<f2 / f23<0.57, and -0.11<f2 / f24<-1.03; Wherein, f2 is the focal length of the second lens group, f21 is the focal length of the seventh lens, f22 is the focal length of the eighth lens, f23 is the focal length of the ninth lens, and f24 is the focal length of the tenth lens; The third lens group includes, arranged from front to back, an eleventh lens with positive power, a twelfth lens with positive power, a thirteenth lens with negative power, a fourteenth lens with positive power, and a fifteenth lens with negative power, wherein the eleventh lens is an aspherical lens; The third lens group and the eleventh lens, the twelfth lens, the thirteenth lens, the fourteenth lens and the fifteenth lens satisfy the following relationship: 0.38<f3 / f31<3.38, and 0.29<f3 / f32<2.62, and -1.18<f3 / f33<-0.13, and 0<f3 / f34<0.07, and -5.9<f3 / f35<-0.66; Wherein, f3 is the focal length of the third lens group, f31 is the focal length of the eleventh lens, f32 is the focal length of the twelfth lens, f33 is the focal length of the thirteenth lens, f34 is the focal length of the fourteenth lens, and f35 is the focal length of the fifteenth lens; The fourth lens group includes a sixteenth lens with positive power, a seventeenth lens with negative power and an eighteenth lens with positive power, which are arranged in sequence from front to back, wherein the eighteenth lens is an aspherical lens; The fourth lens group and the sixteenth lens, the seventeenth lens and the eighteenth lens satisfy the following relationship: 0.13<f4 / f41<1.18, and -2.17<f4 / f42<-0.24, and 0.46<f4 / f43<4.13; Among them, f4 is the focal length of the fourth lens group, f41 is the focal length of the sixteenth lens, f42 is the focal length of the seventeenth lens, and f43 is the focal length of the eighteenth lens.

2. The zoom lens according to claim 1, wherein: The first lens and the second lens constitute a first cemented lens; the fifth lens and the sixth lens constitute a second cemented lens.

3. The zoom lens according to claim 1, wherein: The ninth lens and the tenth lens constitute a third cemented lens.

4. The zoom lens according to claim 1, wherein: The twelfth lens and the thirteenth lens constitute a fourth cemented lens; the fourteenth lens and the fifteenth lens constitute a fifth cemented lens.

5. The zoom lens according to claim 1, wherein: The sixteenth lens and the seventeenth lens constitute a sixth cemented lens.

6. An imaging device, characterized in that: The imaging device comprises the zoom lens as claimed in any one of claims 1 to 5.

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