A zoom lens and a monitoring device

Abstract

The present invention discloses a zoom lens and a monitoring device, which comprise a first lens group, a second lens group, a third lens group and a fourth lens group; the first lens group includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens; the second lens group sequentially includes a sixth lens, a seventh lens, an eighth lens, a ninth lens and a tenth lens from the object side to the image side; the third lens group includes an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens and a fifteenth lens; the fourth lens group includes a sixteenth lens, a seventeenth lens, an eighteenth lens, a nineteenth lens, a twentieth lens, a twenty-first lens, a twenty-second lens, a twenty-third lens, a twenty-fourth lens, a twenty-fifth lens and a twenty-sixth lens; the second lens group and the third lens group can move along the optical axis direction respectively; the present invention has a large zoom ratio, and each lens is a spherical lens, reducing the processing difficulty and processing cost.

Description

Technical Field

[0001] The present invention relates to the technical field of optical lenses, and particularly to a zoom lens and a monitoring device. Background Art

[0002] With the rapid development of science and technology, people have a higher understanding of security, and monitoring lenses have emerged accordingly. In recent years, monitoring lenses have become a major force in the security industry, driving the continuous progress and rapid development of the security industry. The types of monitoring lenses have become increasingly rich as the security market continues to expand. However, with the widespread use of monitoring lenses, people have paid more and more attention to performance issues such as the quality of their imaging effects and the size of the field of view angles. There is a need to meet the search in a wide area under a large field of view and also to meet the precise observation under a small field of view. Therefore, the demand for zoom lenses with a relatively large zoom ratio has become increasingly large. Currently, the existing security monitoring lenses generally have a relatively low zoom ratio and cannot meet the requirements. Summary of the Invention

[0003] The main objective of the present invention is to provide a zoom lens, aiming to improve the technical problem that the existing security monitoring lenses generally have a relatively low zoom ratio and cannot meet the requirements.

[0004] To achieve the above objective, the present invention provides a zoom lens, which includes a first lens group, a second lens group, a third lens group, and a fourth lens group sequentially arranged from the object side to the image side along the optical axis direction:

[0005] The first lens group sequentially includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens from the object side to the image side;

[0006] The second lens group sequentially includes a sixth lens, a seventh lens, an eighth lens, a ninth lens, and a tenth lens from the object side to the image side;

[0007] The third lens group sequentially includes an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens, and a fifteenth lens from the object side to the image side; and,

[0008] The fourth lens group sequentially includes a sixteenth lens, a seventeenth lens, an eighteenth lens, a nineteenth lens, a twentieth lens, a twenty - first lens, a twenty - second lens, a twenty - third lens, a twenty - fourth lens, a twenty - fifth lens, and a twenty - sixth lens from the object side to the image side;

[0009] Among them, the second lens group and the third lens group can be respectively moved along the optical axis direction, and the lenses of each lens group are all spherical lenses;

[0010] The zoom lens satisfies the following condition:

[0011] Ft / Fw = 100;

[0012] L2 ≤ 301.2079 mm;

[0013] L3 ≤ 301.2079 mm;

[0014] Wherein, Ft is the maximum focal length of the zoom lens, Fw is the minimum focal length of the zoom lens, L2 is the distance that the second lens group moves along the optical axis, and L3 is the distance that the third lens group moves along the optical axis.

[0015] Optionally, the first lens has a negative optical power, the second lens has a positive optical power, the third lens has a positive optical power, the fourth lens has a positive optical power, and the fifth lens has a positive optical power.

[0016] Optionally, the optical power of the first lens is φG101, wherein, -0.0022 ≤ φG101 ≤ -0.0020.

[0017] Optionally, the sixth lens has a negative optical power, the seventh lens has a negative optical power, the eighth lens has a negative optical power, the ninth lens has a positive optical power, and the tenth lens has a negative optical power.

[0018] Optionally, the optical power of the sixth lens is φG201, wherein, -0.012 ≤ φG201 ≤ -0.0101.

[0019] Optionally, the eleventh lens has a positive optical power, the twelfth lens has a negative optical power, the thirteenth lens has a positive optical power, the fourteenth lens has a positive optical power, and the fifteenth lens has a positive optical power.

[0020] Optionally, the optical power of the eleventh lens is φG301, wherein, 0.004 ≤ φG301 ≤ 0.006.

[0021] Optionally, the sixteenth lens has a negative optical power, the seventeenth lens has a positive optical power, the eighteenth lens has a negative optical power, the nineteenth lens has a positive optical power, the twentieth lens has a positive optical power, the twenty-first lens has a negative optical power, the twenty-second lens has a positive optical power, the twenty-third lens has a negative optical power, the twenty-fourth lens has a positive optical power, the twenty-fifth lens has a positive optical power, and the twenty-sixth lens has a negative optical power.

[0022] Optionally, the optical power of the sixteenth lens is φG401, wherein, -0.067 ≤ φG401 ≤ -0.064.

[0023] The present invention also provides a monitoring device, and the monitoring device includes the zoom lens described in the above technical solution.

[0024] In the technical solution provided by the present invention, the zoom lens includes a first lens group, a second lens group, a third lens group, and a fourth lens group that are sequentially arranged from the object side to the image side. The first lens group sequentially includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens from the object side to the image side; the second lens group sequentially includes a sixth lens, a seventh lens, an eighth lens, a ninth lens, and a tenth lens from the object side to the image side; the third lens group sequentially includes an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens, and a fifteenth lens from the object side to the image side; the fourth lens group includes a sixteenth lens, a seventeenth lens, an eighteenth lens, a nineteenth lens, a twentieth lens, a twenty-first lens, a twenty-second lens, a twenty-third lens, a twenty-fourth lens, a twenty-fifth lens, and a twenty-sixth lens. And the second lens group and the third lens group can be respectively movably arranged along the optical axis direction. The second lens group is used for zooming, and the third lens group is used for focusing. The present invention has a large zoom ratio, and the lenses of each lens group are spherical lenses, which reduces the processing difficulty and processing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0026] Figure 1 It is a schematic structural diagram of an embodiment of the zoom lens provided by the present invention;

[0027] Explanation of the reference numerals in the drawings:

[0028]

[0029]

[0030] The realization of the object, functional features, and advantages of the present invention will be further described with reference to the embodiments and the drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0032] It should be noted that if there are directional indications involved in the embodiments of the present invention, the directional indications are only used to explain the relative positional relationship, movement conditions, etc. between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0033] In addition, if there are descriptions such as "first", "second", etc. involved in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or a solution that satisfies both A and B simultaneously. Moreover, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0034] With the rapid development of science and technology, people have a higher-level understanding of security, and surveillance cameras have emerged accordingly. In recent years, surveillance cameras have become a major force in the security industry, driving the continuous progress and rapid development of the security industry. The types of surveillance cameras have become increasingly rich with the continuous expansion of the security market. However, with the widespread use of surveillance cameras, people are paying more and more attention to performance issues such as the quality of their imaging effects and the size of the field of view angles. It is necessary to meet both the search in a wide area under a large field of view and the precise observation under a small field of view. Therefore, the demand for zoom lenses with a large zoom ratio is increasing. Currently, the existing security surveillance cameras generally have a low zoom ratio and cannot meet the demand.

[0035] In view of this, the main object of the present invention is to provide a zoom lens, aiming to improve the technical problem that the existing security surveillance cameras generally have a low zoom ratio and cannot meet the demand. Please refer to Figure 1 for an embodiment of the zoom lens.

[0036] First of all, it should be noted that the statement "the lens has a positive optical power (or negative optical power)" hereinafter refers to the paraxial optical power calculated by the lens using Gaussian optical theory being positive (or negative). The greater the absolute value of the optical power, the stronger the bending ability of the light rays; the smaller the absolute value of the optical power, the weaker the bending ability of the light rays. When the optical power is positive, the refraction of the light rays is convergent; when the optical power is negative, the refraction of the light rays is divergent. The optical power can be used to characterize a certain refracting surface of a lens (i.e., a surface of the lens), can be used to characterize a certain lens, or can be used to characterize a system formed by multiple lenses together (i.e., a lens group). The "object side (or image side) of the lens" is defined as a specific range through which the imaging light rays pass through the lens surface. The judgment of the convexity and concavity of the lens surface can be based on the judgment method of those with ordinary knowledge in this field, that is, by the positive and negative signs of the radius of curvature (abbreviated as the R value) to judge the convexity and concavity of the lens surface. The R value is commonly used in optical design software, such as Zemax or CodeV. The R value is also commonly found in the lens data sheet of optical design software. Taking the object side as an example, when the R value is positive, it is determined that the object side is a convex surface; when the R value is negative, it is determined that the object side is a concave surface. Conversely, taking the image side as an example, when the R value is positive, it is determined that the image side is a concave surface; when the R value is negative, it is determined that the image side is a convex surface.

[0037] The zoom lens has an object side and an image side that are relatively arranged along the optical axis direction. It can be understood that the object side faces the object to be photographed, and the light transmission direction is from the object side to the image side.

[0038] The zoom lens includes a first lens group 100, a second lens group 200, a third lens group 300, and a fourth lens group 400 that are sequentially arranged from the object side to the image side along the optical axis direction: Among them, the first lens group 100 sequentially includes a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, and a fifth lens 105 from the object side to the image side; the second lens group 200 sequentially includes a sixth lens 201, a seventh lens 202, an eighth lens 203, a ninth lens 204, and a tenth lens 205 from the object side to the image side; the third lens group 300 sequentially includes an eleventh lens 301, a twelfth lens 302, a thirteenth lens 303, a fourteenth lens 304, and a fifteenth lens 305 from the object side to the image side; the fourth lens group 400 includes a sixteenth lens 401, a seventeenth lens 402, an eighteenth lens 403, a nineteenth lens 404, a twentieth lens 405, a twenty-first lens 406, a twenty-second lens 407, a twenty-third lens 408, a twenty-fourth lens 409, a twenty-fifth lens 410, and a twenty-sixth lens 411; and the second lens group 200 and the third lens group 300 can be respectively moved along the optical axis direction, and the lenses of each lens group are all spherical lenses;

[0039] The zoom lens satisfies the following conditions:

[0040] Ft / Fw = 100;

[0041] L2 ≤ 301.2079 mm;

[0042] L3 ≤ 301.2079 mm;

[0043] Wherein, Ft is the maximum focal length of the zoom lens, i.e., the focal length when the zoom lens is at the telephoto end, Fw is the minimum focal length of the zoom lens, i.e., the focal length when the zoom lens is at the wide-angle end, L2 is the distance that the second lens group 200 moves along the optical axis direction, and L3 is the distance that the third lens group 300 moves along the optical axis direction.

[0044] The zoom lens satisfies the following conditions:

[0045] 0.046 < Fw / F100 < 0.068;

[0046] 0.022 < Ft / F100 < 0.026;

[0047] -0.238 < Fw / F200 < -0.233;

[0048] -23.742 < Ft / F200 < -23.710;

[0049] 0.102 < Fw / F300 < 0.123;

[0050] 11.723 < Ft / F300 < 11.763;

[0051] 0.146 < Fw / F400 < 0.169;

[0052] 16.000 < Ft / F400 < 16.122;

[0053] Wherein, Ft is the maximum focal length of the zoom lens, i.e., the focal length when the zoom lens is at the telephoto end, Fw is the minimum focal length of the zoom lens, i.e., the focal length when the zoom lens is at the wide-angle end, F100 is the focal length of the first lens group, F200 is the focal length of the second lens group, F300 is the focal length of the third lens group, and F400 is the focal length of the fourth lens group.

[0054] In the technical solution provided by the present invention, the zoom lens includes a first lens group 100, a second lens group 200, a third lens group 300, and a fourth lens group 400 arranged in sequence from the object side to the image side. The second lens group 200 and the third lens group 300 are movably arranged along the optical axis direction respectively. The second lens group 200 is used for zooming, and the third lens group 300 is used for focusing. By matching and combining lenses of different materials, and reasonably distributing the optical power and air gap, the zoom lens of the present invention has a large zoom ratio, and the lenses of each lens group are all spherical lenses, which reduces the processing difficulty and processing cost.

[0055] It can be understood that the zoom lens further includes a lens barrel. The first lens group 100, the second lens group 200, the third lens group 300, and the fourth lens group 400 are all installed in the lens barrel. Moreover, the second lens group 200 and the third lens group 300 are movably installed in the lens barrel to realize the zoom of the zoom lens through the movement of the second lens group 200 and the third lens group 300 along the optical axis direction.

[0056] Furthermore, the zoom lens further includes a first driving component and a second driving component. The first driving component is connected to the second lens group 200 to drive the second lens group 200 to move, and the second lens group 200 is connected to the third lens group 300 to drive the third lens group 300 to move.

[0057] The specific limitations of the first driving component and the second driving component are not limited here. In this embodiment, the first driving component includes a first mounting cylinder and a first driving motor. The lenses of the second lens group 200 are all fixedly installed in the first mounting cylinder. The first mounting cylinder is movably installed in the lens barrel along the optical axis direction. The first driving motor is drivingly connected to the first mounting cylinder to drive the first mounting cylinder to move through the first driving motor. The second driving component includes a second mounting cylinder and a second driving motor. The lenses of the third lens group 300 are all fixedly installed in the second mounting cylinder. The second mounting cylinder is movably installed in the lens barrel along the optical axis direction. The second driving motor is drivingly connected to the second mounting cylinder to drive the second mounting cylinder to move through the second driving motor.

[0058] Specifically, in this embodiment, the first lens 101 has a negative optical power, the second lens 102 has a positive optical power, the third lens 103 has a positive optical power, the fourth lens 104 has a positive optical power, and the fifth lens 105 has a positive optical power.

[0059] More specifically, the first lens 101 is a biconcave lens, the second lens 102 is a biconvex lens, the third lens 103 is a biconvex lens, and the fourth lens 104 is a convex lens. Among them, the object side of the fourth lens 104 is convex, and the image side is flat. The fifth lens 105 is a meniscus lens, where the object side of the fifth lens 105 is convex and the image side is concave.

[0060] Specifically, the zoom lens satisfies the following conditions:

[0061] -0.791 < f100 / f101 < -0.788. Among them, f101 is the focal length of the first lens.

[0062] Specifically, the optical power of the first lens 101 is φG101, where -0.0020 ≤ φG101 ≤ -0.0019.

[0063] Specifically, in this embodiment, the sixth lens 201 has a negative optical power, the seventh lens 202 has a negative optical power, the eighth lens 203 has a negative optical power, the ninth lens 204 has a positive optical power, and the tenth lens 205 has a negative optical power.

[0064] More specifically, the sixth lens 201 is a meniscus lens, where the object side of the sixth lens 201 is convex and the image side is concave. The seventh lens 202 is a meniscus lens, where the object side of the seventh lens 202 is convex and the image side is concave. The eighth lens 203 is a biconcave lens, the ninth lens 204 is a biconvex lens, and the tenth lens 205 is a biconcave lens.

[0065] Specifically, the zoom lens satisfies the following conditions:

[0066] 0.400 < f200 / f201 < 0.412; where f201 is the focal length of the sixth lens.

[0067] Specifically, the optical power of the sixth lens 201 is φG201, where -0.012 ≤ φG201 ≤ -0.011.

[0068] Specifically, the ninth lens 204 and the tenth lens 205 form a first cemented lens. The first cemented lens has a positive optical power, and the first cemented lens satisfies the following conditions: -0.152 < f200 / f210 < -0.148; where F210 is the focal length of the first cemented lens.

[0069] It can be understood that the cemented lens can effectively reduce the assembly difficulty and manufacturing cost. At the same time, the cemented lens can well correct the chromatic aberration in the optical system, making the color restoration degree higher. White light is composed of many monochromatic lights, and the refractive index of the lens for different monochromatic lights is different. The shorter the wavelength, the larger the refractive index, and the longer the wavelength, the smaller the refractive index. When a beam of white light passes through the lens refraction, due to the different refractive indices of light with different wavelengths, the white light is dispersed into various wavelengths of light in the ultraviolet band, visible band, and infrared band ranges, resulting in the image formed when passing through the lens having a colored edge. Specifically, at a point on the object side, a color spot may be formed on the image side, forming chromatic aberration, making the imaging blurred. Therefore, chromatic aberration has become a serious defect in lens imaging. The cemented lens is formed by gluing multiple lenses together. When light passes through one of the lenses of the cemented lens and refracts, chromatic aberration will occur. When the refracted light continues to pass through another lens, the generated chromatic aberration is exactly the opposite and can cancel out the previously appeared chromatic aberration, thus achieving the purpose of eliminating chromatic aberration.

[0070] Specifically, in this embodiment, the eleventh lens 301 has a positive optical power, the twelfth lens 302 has a negative optical power, the thirteenth lens 303 has a positive optical power, the fourteenth lens 304 has a positive optical power, and the fifteenth lens 305 has a positive optical power.

[0071] More specifically, the eleventh lens 301 is a biconvex lens, the twelfth lens 302 is a meniscus lens. Among them, the object side surface of the twelfth lens 302 is convex, and the image side surface is concave. The thirteenth lens 303 is a meniscus lens. Among them, the object side surface of the thirteenth lens 303 is convex, and the image side surface is concave. The fourteenth lens is a biconvex lens, and the fifteenth lens 305 is a biconvex lens.

[0072] Specifically, the zoom lens satisfies the following conditions:

[0073] 0.400 < f300 / f301 < 0.412; where F301 is the focal length of the eleventh lens.

[0074] Specifically, the optical power of the eleventh lens 301 is φG301, where 0.0045 ≤ φG301 ≤ 0.0055.

[0075] Specifically, the twelfth lens 302 and the thirteenth lens 303 form a second cemented lens. The second cemented lens has a negative optical power, and the second cemented lens satisfies the following conditions: -0.142 < f300 / f310 < -0.1390; where F310 is the focal length of the second cemented lens.

[0076] Specifically, in this embodiment, the sixteenth lens 401 has a negative optical power, the seventeenth lens 402 has a positive optical power, the eighteenth lens 403 has a negative optical power, the nineteenth lens 404 has a positive optical power, the twentieth lens 405 has a positive optical power, the twenty - first lens 406 has a negative optical power, the twenty - second lens 407 has a positive optical power, the twenty - third lens 408 has a negative optical power, the twenty - fourth lens 409 has a positive optical power, the twenty - fifth lens 410 has a positive optical power, and the twenty - sixth lens 411 has a negative optical power.

[0077] More specifically, the sixteenth lens 401 is a biconcave lens, the seventeenth lens 402 is a convex lens, where the object side surface of the seventeenth lens 402 is convex and the image side surface is flat, the eighteenth lens 403 is a meniscus lens, where the object side surface of the eighteenth lens 403 is convex and the image side surface is concave, the nineteenth lens 404 is a biconvex lens, the twentieth lens 405 is a biconvex lens, the twenty - first lens 406 is a meniscus lens, where the object side surface of the twenty - third lens 408 is convex and the image side surface is concave, the twenty - second lens 407 is a biconvex lens, the twenty - third lens 408 is a meniscus lens, where the object side surface of the twenty - third lens 408 is convex and the image side surface is concave, the twenty - fourth lens 409 is a meniscus lens, where the object side surface of the twenty - fourth lens 409 is convex and the image side surface is concave, the twenty - fifth lens 410 is a meniscus lens, where the object side surface of the twenty - fifth lens 410 is convex and the image side surface is concave, and the twenty - sixth lens 411 is a meniscus lens, where the object side surface of the twenty - sixth lens 411 is convex and the image side surface is concave.

[0078] Specifically, the zoom lens satisfies the following conditions:

[0079] -0.451 < f400 / f401 < -0.441; where F401 is the focal length of the sixteenth lens.

[0080] Specifically, the optical power of the sixteenth lens 401 is φG401, where -0.060 ≤ φG401 ≤ -0.0068.

[0081] Specifically, the sixteenth lens 401 and the seventeenth lens 402 form the third cemented lens. Specifically, the eighteenth lens 403 and the nineteenth lens 404 form the fourth cemented lens. Specifically, the twenty - first lens 406 and the twenty - second lens 407 form the fifth cemented lens.

[0082] Specifically, the twenty - third lens 408 and the twenty - fourth lens 409 form the sixth cemented lens.

[0083] Specifically, the twenty-fifth lens 410 and the twenty-sixth lens 411 form a seventh cemented lens.

[0084] Specifically, the zoom lens further includes a diaphragm, which is located between the third lens group 300 and the fourth lens group 400. The diaphragm can be made of light-shielding paper, and its function is to accurately adjust the light passing amount. In order to capture clear pictures in low-light scenes, a lens with a larger light flux is required. Therefore, by setting the diaphragm, it is beneficial to control the incident angle (CRA) of the chief ray reaching the imaging element to meet the incident requirements of the chip. Using light-shielding paper to make the diaphragm can ensure the machining accuracy to the greatest extent, reduce machining errors, and facilitate adjustment. A through-hole is provided in the middle of the diaphragm for facilitating the adjustment of light by the diaphragm, and the through-hole adopts a circular through-hole structure.

[0085] Specifically, in this embodiment, the operating temperature of the zoom lens is -30°C to 70°C. The temperature range is wide, which can meet people's needs for using the lens.

[0086] Specifically, the zoom lens further includes an imaging element, which is located on the image side of the fourth lens group 400 and is used to receive the light passing through the above lenses from the object side.

[0087] Specifically, the zoom lens further includes a filter, which is located between the fifth lens 105 and the imaging element. The filter can be an infrared filter. By setting the infrared filter, the zoom lens can filter out infrared light to prevent infrared light from reaching the imaging element and interfering with the normal visible light imaging, thereby improving the imaging quality.

[0088] Specifically, in this embodiment, the parameters of the zoom lens are shown in the following table.

[0089] Table 1 Parameters of each lens of the zoom lens

[0090]

[0091]

[0092]

[0093] Among them, S1 to S46 represent the surface numbers of each lens and the diaphragm. And in the cemented lens, the parameters of the image side surface of the previous lens and the object side surface of the next lens are the same, sharing the same surface number.

[0094] Table 2 Distances between each lens group of the zoom lens

[0095] Wide MID TELE D10 6.8336 193.698 308.0415 D19 408.4376 205.3031 4.9701 D28 1.9022 18.1722 104.1618

[0096] Among them, D10 represents the distance between the first lens group and the second lens group along the optical axis direction, D19 represents the distance between the second lens group and the third lens group along the optical axis direction, D28 represents the distance between the third lens group and the fourth lens group along the optical axis direction, the WIDE column represents the distance between each lens group when the zoom lens is at the minimum focal length, the TELE column represents the distance between each lens group when the zoom lens is at the maximum focal length, and the MID column represents the distance between each lens group when the zoom lens is at a certain focal length between the maximum focal length and the minimum focal length.

[0097] Specifically, in this embodiment, the parameters of the zoom lens are as follows:

[0098] The focal length at the wide-angle end fw = 10 mm, and the focal length at the telephoto end ft = 1003 mm; the aperture number at the wide-angle end Fnow = 2.2, and the aperture number at the telephoto end Fno T = 8.

[0099] The present invention also provides a monitoring device, and the monitoring device includes the zoom lens in the above technical solution. It should be noted that the detailed structure of the zoom lens of the monitoring device can refer to the embodiment of the above zoom lens, which will not be elaborated here; since the above zoom lens is used in the monitoring device of the present invention, therefore, the embodiment of the monitoring device of the present invention includes all the technical solutions of all the embodiments of the above zoom lens, and the achieved technical effects are also exactly the same, which will not be elaborated here.

[0100] The above are only optional embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made under the inventive concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A zoom lens, characterized in that, The zoom lens includes a first lens group, a second lens group, a third lens group, and a fourth lens group arranged in sequence from the object side to the image side along the optical axis direction: The first lens group includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens in sequence from the object side to the image side; The second lens group includes a sixth lens, a seventh lens, an eighth lens, a ninth lens, and a tenth lens in sequence from the object side to the image side; The third lens group includes an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens, and a fifteenth lens in sequence from the object side to the image side; The fourth lens group includes a sixteenth lens, a seventeenth lens, an eighteenth lens, a nineteenth lens, a twentieth lens, a twenty-first lens, a twenty-second lens, a twenty-third lens, a twenty-fourth lens, a twenty-fifth lens, and a twenty-sixth lens in sequence from the object side to the image side; Wherein, the second lens group and the third lens group can move respectively along the optical axis direction, and the lenses of each lens group are all spherical lenses; The zoom lens satisfies the following conditions: Ft / Fw = 100; L2 ≤ 301.2079 mm; L3 ≤ 301.2079 mm; Wherein, Ft is the maximum focal length of the zoom lens, Fw is the minimum focal length of the zoom lens, L2 is the distance that the second lens group moves along the optical axis direction, and L3 is the distance that the third lens group moves along the optical axis direction.

2. The zoom lens according to claim 1, wherein The first lens has a negative optical power, the second lens has a positive optical power, the third lens has a positive optical power, the fourth lens has a positive optical power, and the fifth lens has a positive optical power.

3. The zoom lens according to claim 2, characterized in that, The optical power of the first lens is φG101, wherein, -0.0022 ≤ φG101 ≤ -0.0020.

4. The zoom lens according to claim 1, wherein The sixth lens has a negative optical power, the seventh lens has a negative optical power, the eighth lens has a negative optical power, the ninth lens has a positive optical power, and the tenth lens has a negative optical power.

5. The zoom lens according to claim 4, wherein, The optical power of the sixth lens is φG201, wherein, -0.012 ≤ φG201 ≤ -0.0101.

6. The zoom lens according to claim 1, characterized in that, The eleventh lens has a positive optical power, the twelfth lens has a negative optical power, the thirteenth lens has a positive optical power, the fourteenth lens has a positive optical power, and the fifteenth lens has a positive optical power.

7. The zoom lens according to claim 6, characterized in that, The optical power of the eleventh lens is φG301, wherein, 0.004 ≤ φG301 ≤ 0.

006.

8. The zoom lens according to claim 1, characterized in that, The sixteenth lens has a negative optical power, the seventeenth lens has a positive optical power, the eighteenth lens has a negative optical power, the nineteenth lens has a positive optical power, the twentieth lens has a positive optical power, the twenty-first lens has a negative optical power, the twenty-second lens has a positive optical power, the twenty-third lens has a negative optical power, the twenty-fourth lens has a positive optical power, the twenty-fifth lens has a positive optical power, and the twenty-sixth lens has a negative optical power.

9. The zoom lens according to claim 8, characterized in that, The optical power of the sixteenth lens is φG401, wherein, -0.067 ≤ φG401 ≤ -0.

064.

10. A monitoring device, characterized in that, The monitoring device includes the zoom lens according to any one of claims 1-9.

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