Zoom lens and monitoring device

Abstract

The application discloses a zoom lens and a monitoring device, which comprises a lens assembly and a driving device, the lens assembly comprises a plurality of lens groups composed of a plurality of lenses, the driving device is connected with the plurality of lens groups, the plurality of lens groups are arranged along the optical axis direction of the zoom lens, and sequentially comprise a first lens group, a second lens group, a third lens group, a fourth lens group and a fifth lens group from the object side to the image side, the first lens group has positive focal power, the second lens group has negative focal power, the third lens group has positive focal power, the fourth lens group has negative focal power, and the fifth lens group has positive focal power, and the zoom is realized by changing the interval between adjacent lens groups through the driving device. The technical scheme provided by the application can realize wide-angle wide field of view to narrow field of view target imaging in a large range, can be used for 4K high-definition imaging, and the lens volume is small.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical lens, in particular to a zoom lens and a monitoring device. BACKGROUND

[0002] Many optical instruments require the magnification of the optical system to be variable, so that the same instrument can see both the overall large field of view and low magnification, and carefully observe the small field of view and high magnification of the local part. Changing the lens is a common method, such as a microscope objective, etc. However, this method of changing the objective lens discontinuously changes the size of the image. In order to continuously change the size of the image, a zoom lens is developed.

[0003] In recent years, the zoom lens technology has developed rapidly, and great breakthroughs have been made in imaging quality, zoom ratio range, size, field of view, etc., making the application field of zoom lens more and more extensive, from imaging instruments to cameras, telescopes, microscopes, monitoring systems, machine vision, to photo mobile phones, which plays an important role in our daily life, art and work.

[0004] At present, the pixel of the high magnification lens on the market is generally low, and the existing zoom lens often cannot achieve compatibility of high magnification and size. The increase of magnification will cause the sharp change of the size of the lens, and the zoom lens cannot well realize the target imaging of a wide field of view to a narrow field of view.

[0005] With the maturity of 4K imaging and video signal processing technology in the security field, the demand for small size, compact structure and 4K imaging of high-definition lens becomes more and more intense, so the present application aims to meet the lens demand of 4K imaging in the security field. SUMMARY

[0006] The main purpose of the present application is to provide a zoom lens and a monitoring device, which can realize target imaging of a wide field of view to a narrow field of view, increase the monitoring performance of the monitoring device, and meet the demand of high image quality.

[0007] In order to achieve the above purpose, the present application provides a zoom lens, which comprises a lens assembly and a driving device, the lens assembly comprises a plurality of lens groups composed of a plurality of lenses, the driving device is connected with the plurality of lens groups, and the plurality of lens groups are arranged along the optical axis direction of the zoom lens in order from the object side to the image side, and comprise:

[0008] The first lens group has positive refractive power;

[0009] The second lens group has negative refractive power;

[0010] The third lens group has positive refractive power;

[0011] a fourth lens group having negative refractive power; and

[0012] a fifth lens group having positive refractive power;

[0013] wherein the plurality of lens groups are movably arranged along the optical axis direction, and the zooming is achieved by changing the interval between adjacent lens groups through the driving device;

[0014] the zoom lens satisfies the following conditions,

[0015] an optical total length of the zoom lens is TTL, and TTL≤140mm;

[0016] a focal length of the zoom lens is f, and 9mm≤f≤170mm;

[0017] an F number of the zoom lens is FNO, and the value range of FNO is 1.6~4.

[0018] Optionally, the length of the diagonal of the detector that can be adapted by the zoom lens, i.e. the maximum image height, is 12.78mm, which is used for 4K high-definition imaging.

[0019] Optionally, the first lens group comprises, from the object side to the image side, a first lens, a second lens, a third lens, a fourth lens, and a fifth lens, and all of them are spherical mirrors.

[0020] The first lens and the second lens are cemented lenses.

[0021] Optionally, the second lens group comprises, from the object side to the image side, a sixth lens, a seventh lens, an eighth lens, and a ninth lens.

[0022] The sixth lens and the seventh lens are aspherical mirrors, and the seventh lens, the eighth lens, and the ninth lens are spherical mirrors.

[0023] The eighth lens and the ninth lens are cemented lenses.

[0024] Optionally, the third lens group comprises a tenth lens, and the tenth lens is a spherical mirror.

[0025] Optionally, the fourth lens group comprises, from the object side to the image side, an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens, and a fifteenth lens.

[0026] The eleventh lens, the fourteenth lens, and the fifteenth lens are spherical mirrors.

[0027] The twelfth lens and the thirteenth lens are aspherical mirrors.

[0028] The fourteenth lens and the fifteenth lens are cemented lenses.

[0029] Optionally, the fifth lens group comprises, in order from the object side to the image side, a sixteenth lens, a seventeenth lens, an eighteenth lens, a nineteenth lens, a twentieth lens, and a twenty-first lens.

[0030] The sixteenth lens, the seventeenth lens, the eighteenth lens, the nineteenth lens, and the twentieth lens are spherical lenses.

[0031] The twenty-first lens is an aspherical lens.

[0032] The sixteenth lens, the seventeenth lens, and the eighteenth lens are three-cemented lenses, and the nineteenth lens and the twentieth lens are cemented lenses.

[0033] Optionally, the zoom lens satisfies the following condition: Ft / Fw=18.89, where Ft is the maximum focal length of the zoom lens, and Fw is the minimum focal length of the zoom lens.

[0034] Optionally, the zoom lens further comprises a diaphragm, which is arranged on the front side of the fourth lens group and is fixed relative to the fourth lens group so as to be driven by the fourth lens group to move along the front-rear direction.

[0035] The present application also provides a monitoring device comprising a zoom lens, wherein the zoom lens comprises a lens assembly and a driving device, the lens assembly comprises a plurality of lens groups, the driving device is connected to the plurality of lens groups, the plurality of lens groups are arranged along the optical axis direction of the zoom lens, and in order from the object side to the image side, the plurality of lens groups comprise: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having negative refractive power; and a fifth lens group having positive refractive power; wherein the plurality of lens groups are movably arranged in the direction of the optical axis, and the driving device changes the interval between adjacent lens groups to realize zooming; the zoom lens satisfies the following conditions: the total length of the zoom lens is TTL, TTL≤140mm; the focal length of the zoom lens is f, 9mm≤f≤170mm; and the F number of the zoom lens is FNO, and the value range of FNO is 1.6~4.

[0036] The zoom lens comprises a plurality of lens groups, each lens group comprises a plurality of lenses, the focal powers of different lens groups are different, and zooming is realized by changing the interval between adjacent lens groups through a driving device; the entire zoom lens has a small length and a compact structure; the technical solution can provide a zoom lens with a large zoom ratio, can realize target imaging in a wide range from a wide-angle wide field of view to a narrow field of view, increases the monitoring performance of a monitoring device, and meets the demand for high image quality. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only represent some of the embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort based on the drawings shown.

[0038] Figure 1 A plan view of an embodiment of the zoom lens provided by the present application is shown in the figure.

[0039] Figure 2 A plan view of an embodiment of the zoom lens provided by the present application is shown in the figure. Figure 1 A schematic view of the distance change between lens groups of the medium zoom lens is shown in the figure.

[0040] Figure 3 A schematic view of the distance change between lens groups of the medium zoom lens is shown in the figure. Figure 1 Another schematic view of the distance change between lens groups of the medium zoom lens is shown in the figure.

[0041] The figure number of the embodiment provided by the present application is explained as follows:

[0042]

[0043] The implementation, functional features and advantages of the present application will be further explained with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments only represent some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort belong to the protection scope of the present application.

[0045] It should be noted that if the embodiments of the present application involve directionality indication (such as up, down, left, right, front, back, etc.), the directionality indication is only used to explain the relative position relationship, movement condition, etc. between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directionality indication also changes accordingly.

[0046] In addition, if the description of "first", "second" and the like is involved in the embodiments of the present application, the description of "first", "second" and the like is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. For example, "A and / or B" includes A scheme, or B scheme, or A and B simultaneously satisfy the scheme. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of the ordinary skilled in the art. When the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope required by the present application.

[0047] In recent years, the zoom lens technology has developed rapidly, whether in imaging quality or in the range of zoom ratio, size, field of view, etc. Great breakthroughs have been made, making the application field of zoom lens more and more widely, from imaging instruments to cameras, telescopes, microscopes, monitoring systems, machine vision, to photo mobile phones, which plays an important role in our daily life, art and work. The current market high-magnification lens generally has low pixels, and the existing zoom lens often cannot achieve large magnification and volume compatibility. The increase of magnification will cause the sharp change of lens volume, and the zoom lens cannot well realize the wide-angle wide field of view to narrow field of view of large range target imaging.

[0048] In view of this, the present application provides a zoom lens 100, which can realize wide-angle wide field of view to narrow field of view of large range target imaging, increase the monitoring performance of monitoring equipment, and meet the demand of high image quality. Figures 1 to 3 An embodiment of the zoom lens 100 provided by the present application is provided.

[0049] Please refer to Figure 1The present application provides a zoom lens 100 comprising a lens assembly and a driving device (not shown in the figure), the lens assembly comprises a plurality of lens groups composed of a plurality of lenses, the driving device drives a plurality of the lens groups, a plurality of the lens groups are arranged along the optical axis direction of the zoom lens 100, and in order from the object side to the image side, the first lens group, the second lens group, the third lens group, the fourth lens group and the fifth lens group are sequentially included, the first lens group has positive refractive power, the second lens group has negative refractive power, the third lens group has positive refractive power, the fourth lens group has negative refractive power, and the fifth lens group has positive refractive power; wherein the plurality of lens groups are movably arranged in the optical axis extension direction, and the driving device changes the interval between adjacent lens groups to realize zooming; the zoom lens 100 satisfies the following conditions, the total length of the zoom lens 100 is TTL, TTL≤140mm; the focal length of the zoom lens 100 is f, 9mm≤f≤170mm; the F number of the zoom lens 100 is FNO, and the value range is 1.6~4.

[0050] In the technical scheme of the present application, first of all, it can be understood that the optical power is equal to the difference between the image beam convergence degree and the object beam convergence degree, which represents the ability of the imaging device to deflect light. The greater the absolute value of the optical power, the stronger the bending ability of the light, and the smaller the absolute value of the optical power, the weaker the bending ability of the light. When the optical power is positive, the refraction of light is convergent; when the optical power is negative, the refraction of light is divergent. The optical power can be used to represent a certain refractive surface of a lens (i.e. a surface of a lens), a certain lens, or a system formed by multiple lenses (i.e. a lens group). In the present scheme, the zoom lens 100 comprises a lens assembly and a driving device, the lens assembly comprises a plurality of lens groups composed of a plurality of lenses, a plurality of the lens groups are arranged along the optical axis direction of the zoom lens 100, and in order from the object side to the image side, the first lens group 1 with positive refractive power, the second lens group 2 with negative refractive power, the third lens group 3 with positive refractive power, the fourth lens group 4 with negative refractive power, and the fifth lens group 5 with positive refractive power are sequentially included, the first lens group 1 is a front fixed group, which makes the object to be photographed fall on the object point of the variable magnification group, the second lens group 2, the third lens group 3 and the fourth lens group 4 constitute a variable magnification group, each lens group of the variable magnification group is movably arranged in the optical axis extension direction, the driving device changes the interval between adjacent lens groups to realize zooming, the fifth lens group 5 is a compensation group, each lens group of the fifth lens group 5 is movably arranged in the optical axis extension direction, and the fifth lens group 5 moves along the optical axis under the driving of the driving device, so that the zoom lens 100 focuses.

[0051] In the embodiment, the length of the diagonal of the detector that can be adapted by the zoom lens, i.e. the maximum image height, is 12.78 mm, the imaging resolution is 3864*2160, the pixel size is 2.9 um, and the zoom lens is used for 4K high-definition imaging, which can meet the needs of high-definition imaging in the security field.

[0052] Specifically, referring to Figure 1 , the first lens group 1 comprises, in order from the object side to the image side, a first lens 11 with negative refractive power, a second lens 12 with negative refractive power, a third lens 13 with positive refractive power, a fourth lens 14 with positive refractive power, and a fifth lens 15 with positive refractive power, and each of them is a spherical lens. The first lens group 1 and the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, and the fifth lens 15 satisfy the following conditions: -0.05 < f1 / f11 < -0.04, and -0.075 < f1 / f12 < -0.065, and 0.20 < f1 / f13 < 0.30, and 0.41 < f1 / f14 < 0.45, and 0.45 < f1 / f15 < 0.52; 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, and f15 is the focal length of the fifth lens 15.

[0053] It can be understood that, generally, light propagates from left to right, so the left lens of the lens is R1 and the right lens is R2 (R is the radius of curvature of the two spherical surfaces). When the left spherical surface is concave, R1 is negative, otherwise it is positive; when the right spherical surface is concave, R2 is positive, otherwise it is negative; when the left or right surface is a plane, the radius of curvature is infinite. The first lens 11 is a convex-concave lens, i.e. R1 of the first lens 11 is positive and R2 is positive, the second lens 12 is a convex-concave lens, the third lens 13 is a convex-concave lens, the fourth lens 14 is a convex-concave lens, and the fifth lens 15 is a convex-plane lens, i.e. the left spherical surface of the fifth lens 15 is convex and the right spherical surface is a plane. Furthermore, the ratio of the focal length of the first lens group 1 to the focal length of each lens is as follows: f1 / f11 = -0.047, f1 / f12 = -0.72, f1 / f13 = 0.26, f1 / f14 = 0.44, and f1 / f15 = 0.48. The refractive power of the first lens 11 to the fifth lens 15 is -0.0007, -0.011, 0.0039, 0.0066, and 0.0073, respectively. Further, the first lens 11 and the second lens 12 form a first cemented lens with positive refractive power, and the ratio of the focal length of the first lens group 1 to the focal length of the first cemented lens is f1 / f1112 = -0.1433.

[0054] Please refer to Figure 1 , specifically, the second lens group 2 includes, in order from the object side to the image side, a sixth lens 21 with negative focal power, a seventh lens 22 with negative focal power, an eighth lens 23 with negative focal power, and a ninth lens 24 with positive focal power; the sixth lens 21 and the seventh lens 22 are both aspherical lenses, and the seventh lens 22, the eighth lens 23, and the ninth lens 24 are all spherical lenses. More specifically, the sixth lens 21 is a plano-concave lens, i.e., the left side spherical surface of the sixth lens 21 is a plane, and the right side spherical surface is a concave surface, the seventh lens 22 is a plano-concave lens, the eighth lens 23 is a double-concave lens, i.e., R1 of the eighth lens 23 is negative, and R2 is positive, the ninth lens 24 is a double-convex lens, i.e., R1 of the ninth lens 24 is positive, and R2 is negative, and the ratio of the focal length of the second lens group 2 to the focal length of each lens therein is specifically as follows: f2 / f21=0.51, f2 / f22=0.36, f2 / f23=0.15, f2 / f24=-0.25, and the focal power of the sixth lens 21 to the ninth lens 24 is in turn: -0.046, -0.034, -0.014, 0.023. Further, the eighth lens 23 and the ninth lens 24 constitute a second cemented lens with negative focal power, and satisfy the following condition: 0.050

[0055] Specifically, please refer to Figure 1 , the third lens group 3 includes a tenth lens with positive focal power, the tenth lens is a convex plane mirror, i.e., the left side spherical surface of the tenth lens is a convex surface, and the right side spherical surface is a plane, the tenth lens is a spherical lens, and the focal power of the tenth lens is: 0.014.

[0056] In this embodiment, please refer to Figure 1In particular, the fourth lens group 4 comprises, sequentially from the object side to the image side, a eleventh lens 41 with positive refractive power, a twelfth lens 42 with positive refractive power, a thirteenth lens 43 with negative refractive power, a fourteenth lens 44 with negative refractive power, and a fifteenth lens 45 with negative refractive power, wherein the eleventh lens 41, the fourteenth lens 44 and the fifteenth lens 45 are all spherical lenses; the twelfth lens 42 and the thirteenth lens 43 are aspherical lenses. The fourth lens group 4 and the eleventh lens 41, the twelfth lens 42, the thirteenth lens 43, the fourteenth lens 44 and the fifteenth lens 45 satisfy the following conditions: 0.65 < f4 / f41 < 0.68, and 0.94 < f4 / f42 < 0.97, and -0.34 < f4 / f43 < -0.30, -0.38 < f4 / f44 < -0.34, and -1.35 < f4 / f45 < -1.30; wherein f4 is the focal length of the fourth lens group 4, f41 is the focal length of the eleventh lens 41, f42 is the focal length of the twelfth lens 42, f43 is the focal length of the thirteenth lens 43, f44 is the focal length of the fourteenth lens 44, and f45 is the focal length of the fifteenth lens 45. More specifically, in the present embodiment, the eleventh lens 41 is a convex-concave lens, i.e. R1 of the eleventh lens 41 is positive and R2 is positive, the twelfth lens 42 is a biconvex lens, the thirteenth lens 43 is a biconcave lens, the fourteenth lens 44 is a convex-concave lens, and the fifteenth lens 45 is a convex-plane lens, and the ratio of the focal length of the fourth lens group 4 to the focal length of each lens is specifically as follows: f4 / f41 = 0.68, f4 / f42 = 0.96, f4 / f43 = -0.32, f4 / f44 = -0.36, and f4 / f45 = -1.32, and the refractive powers of the eleventh lens 41 to the fifteenth lens 45 are in turn: 0.027, 0.037, -0.012, -0.014, and -0.052. Further, the fourteenth lens 44 and the fifteenth lens 45 form a third cemented lens with negative refractive power, and satisfy the following condition: -0.58 < f4 / f4445 < -0.56, wherein f4 is the focal length of the fourth lens group 4, and f3334 is the focal length of the third cemented lens. In the present embodiment, the ratio of the focal length of the fourth lens group 4 to the focal length of the third cemented lens is specifically: f4 / f4445 = -0.57.

[0057] In particular, please refer to Figure 1, the fifth lens group 5 includes, sequentially from the object side to the image side, a sixteenth lens 51 with negative refractive power, a seventeenth lens 52 with negative refractive power, an eighteenth lens 53 with positive refractive power, a nineteenth lens 54 with positive refractive power, a twentieth lens 55 with positive refractive power, and a twenty-first lens 56 with positive refractive power; wherein the sixteenth lens 51, the seventeenth lens 52, the eighteenth lens 53, the nineteenth lens 54, and the twentieth lens 55 are all spherical lenses; the twenty-first lens 56 is an aspherical lens; the fifth lens group 5 and the sixteenth lens 51, the seventeenth lens 52, the eighteenth lens 53, the nineteenth lens 54, the twentieth lens 55, and the twenty-first lens 56 satisfy the following relationships: -2.10 < f5 / f51 < -2.00, and -1.08 < f5 / f52 < -1.02, and 0.080 < f5 / f53 < 0.085, and 0.92 < f5 / f54 < 0.95, and 0.18 < f5 / f55 < 0.20, and 1.28 < f5 / f56 < 1.34; wherein f5 is the focal length of the fifth lens group 5, f51 is the focal length of the sixteenth lens 51, f52 is the focal length of the seventeenth lens 52, f53 is the focal length of the eighteenth lens 53, f54 is the focal length of the nineteenth lens 54, f55 is the focal length of the twentieth lens 55, and f56 is the focal length of the twenty-first lens 56. More specifically, in the present embodiment, the sixteenth lens 51 is a double-concave lens, the seventeenth lens 52 is a convex-concave lens, the eighteenth lens 53 is a convex-flat lens, the nineteenth lens 54 is a double-convex lens, the twentieth lens 55 is a double-concave lens, the twenty-first lens 56 is a flat-convex lens, and the ratio of the focal length of the fifth lens group 5 to the focal length of each lens therein is specifically as follows: f5 / f51 = -2.05, f5 / f52 = -1.04, f5 / f53 = 0.083, f5 / f54 = 0.93, f5 / f55 = 0.196, and f5 / f56 = 1.33, and the refractive powers of the sixteenth lens 51 to the twenty-first lens 56 are, in order: -0.060, -0.031, 0.0025, 0.028, 0.0058, and 0.039.Further, the sixteenth lens 51, the seventeenth lens 52 and the eighteenth lens 53 constitute a triplet with negative refractive power, and satisfy the following condition: -1.98 < f5 / f515253 < -1.95, wherein f5 is the focal length of the fifth lens group 5, and f501 is the focal length of the triplet; the nineteenth lens 54 and the twentieth lens 55 constitute a quadlet with negative refractive power, and satisfy the following condition: 0.69 < f5 / f5455 < 0.73, wherein f5 is the focal length of the fifth lens group 5, and f502 is the focal length of the quadlet, and in the embodiment, the specific ratio of the focal length of the fifth lens group 5 and the triplet is f5 / f515253 = -1.97, and the specific ratio of the focal length of the fifth lens group 5 and the quadlet is f5 / f5455 = 0.71.

[0058] Further, the zoom lens further comprises a diaphragm, which is arranged on the front side of the fourth lens group and is fixed relative to the fourth lens group so as to be driven by the fourth lens group to move along the front-rear direction.

[0059] Based on the above, the sixth lens 21, the seventh lens 22, the twelfth lens 42, the thirteenth lens 43 and the twenty-first lens 56 are all aspherical lenses, and it can be understood that the aspherical lens has the characteristic that the curvature continuously changes from the center of the lens to the periphery of the lens, which is different from the spherical lens with constant curvature from the center of the lens to the periphery of the lens. The aspherical lens has better curvature radius characteristics, has the advantages of improving distortion aberration and improving astigmatism aberration, and after the aspherical lens is adopted, the aberration that occurs during imaging can be eliminated as much as possible, thereby improving the imaging quality of the lens.

[0060] Further, in the embodiment, the zoom lens 100 satisfies the following condition: Ft / Fw = 18.89, wherein Ft is the maximum focal length of the zoom lens 100, and Fw is the minimum focal length of the zoom lens 100.

[0061] Wherein the aspherical parameters satisfy the following conditions:

[0062]

[0063] In this formula, z is the sag of the aspherical surface at different apertures, c is the curvature of the aspherical surface, wherein K is the quadratic surface coefficient of the aspherical surface, r is the normalized radius, A, B, C, D, E, F, G and H are the coefficients of each high-order term of the aspherical surface.

[0064] Specifically, please refer to the following Table 1 to Table 3, which provides the specific data of the zoom lens 100 in an embodiment.

[0065] Wherein, S1-S39 in Table 1 represent the surface serial number of each optical element, R represents the curvature radius of the optical element, D represents the thickness or air gap of the optical element, N d represents the d light refractive index of the optical material used, V d represents the d light Abbe number of the optical material used; Table 2 shows the thickness values of each focal length of the examples shown in Table 1, wherein the WIDE column indicates the air gap between the moving groups when the lens is at the minimum focal length, the TELE column indicates the air gap between the moving groups when the lens is at the maximum focal length, and the MID column indicates the air gap between the moving groups when the lens is at a focal length between the maximum and minimum focal lengths; Table 3 gives the aspheric coefficients of all surfaces of the aspheric lens.

[0066] Table 1

[0067]

[0068] Table 2

[0069]

[0070] Table 3

[0071]

[0072] The present application also proposes a monitoring device comprising the zoom lens 100, which is specifically described with reference to the above-mentioned embodiments. Since the monitoring device adopts all the technical solutions of the above-mentioned embodiments, it also has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0073] The above-mentioned is only the preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation made under the inventive concept of the present application, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present application.

Claims

1. A zoom lens, characterized in that, The zoom lens comprises a lens assembly and a driving device, the lens assembly comprises a plurality of lens groups composed of a plurality of lenses, the driving device drives a plurality of the lens groups, a plurality of the lens groups are arranged along the optical axis direction of the zoom lens in order from the object side to the image side, and sequentially comprise: a first lens group with positive refractive power; a second lens group with negative refractive power; a third lens group with positive refractive power; a fourth lens group with negative refractive power; and a fifth lens group with positive refractive power; wherein the plurality of lens groups are movably arranged in the direction of the optical axis, and the interval between adjacent lens groups is changed by the driving device to realize zooming; the zoom lens satisfies the following conditions, the total length of the zoom lens is TTL, TTL≤140mm; the focal length of the zoom lens is f, 9mm≤f≤170mm; the F number of the zoom lens is FNO, and the value range is 1.6~4; the maximum length of the diagonal line of the detector adapted by the zoom lens, i.e. the maximum image height, is 12.78mm, which is used for 4K high-definition imaging; the zoom lens satisfies the following condition: Ft / Fw=18.89, wherein Ft is the maximum focal length of the zoom lens, and Fw is the minimum focal length of the zoom lens; the first lens group comprises, from the object side to the image side in order, a first lens with negative refractive power, a second lens with negative refractive power, a third lens with positive refractive power, a fourth lens with positive refractive power, and a fifth lens with positive refractive power; the second lens group comprises, from the object side to the image side in order, a sixth lens with negative refractive power, a seventh lens with negative refractive power, an eighth lens with negative refractive power, and a ninth lens with positive refractive power; the third lens group comprises a tenth lens with positive refractive power; the fourth lens group comprises, from the object side to the image side in order, an eleventh lens with positive refractive power, a twelfth lens with positive refractive power, a thirteenth lens with negative refractive power, a fourteenth lens with negative refractive power, and a fifteenth lens with negative refractive power; the fifth lens group comprises, from the object side to the image side in order, a sixteenth lens with negative refractive power, a seventeenth lens with negative refractive power, an eighteenth lens with positive refractive power, a nineteenth lens with positive refractive power, a twentieth lens with positive refractive power, and a twenty-first lens with positive refractive power.

2. The zoom lens according to claim 1, wherein The first lens, the second lens, the third lens, the fourth lens, and the fifth lens are all spherical lenses; The first lens and the second lens are cemented lenses.

3. The zoom lens according to claim 1, wherein The sixth lens and the seventh lens are both aspherical lenses, the seventh lens, the eighth lens, and the ninth lens are all spherical lenses; The eighth lens and the ninth lens are cemented lenses.

4. The zoom lens according to claim 1, wherein The tenth lens is a spherical lens.

5. The zoom lens according to claim 1, wherein The eleventh lens, the fourteenth lens, and the fifteenth lens are all spherical lenses; The twelfth lens and the thirteenth lens are aspherical lenses; The fourteenth lens and the fifteenth lens are cemented lenses.

6. The zoom lens according to claim 1, wherein The sixteenth lens, the seventeenth lens, the eighteenth lens, the nineteenth lens, and the twentieth lens are all spherical lenses; The twenty-first lens is an aspheric lens; The sixteenth lens, the seventeenth lens, the eighteenth lens are three cemented lenses, and the nineteenth lens and the twentieth lens are cemented lenses.

7. The zoom lens according to any one of claims 1 to 6, characterized by The zoom lens further comprises a diaphragm, which is arranged on the front side of the fourth lens group and is fixed relative to the fourth lens group so as to be driven by the fourth lens group to move along the front-back direction.

8. A monitoring device, characterized by The monitoring device comprises the zoom lens according to any one of claims 1 to 7.

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