Zoom lens

Abstract

The zoom lens comprises a focusing lens group, a zoom lens group and a fixed lens group which are sequentially arranged from an object plane to an image plane along an optical axis, the focusing lens group has negative focal power, the zoom lens group has positive focal power, and the fixed lens group has positive focal power; the first lens has negative focal power, the second lens has negative focal power or positive focal power, and the third lens has negative focal power; the fourth lens has positive focal power; the fifth lens has negative focal power, the sixth lens has positive focal power, the seventh lens has negative focal power, the eighth lens has positive focal power, the ninth lens has negative focal power or positive focal power, the tenth lens has negative focal power, and the eleventh lens has positive focal power. The zoom lens can meet the imaging requirement under the full wave band, has the advantages of being small in size and small in distortion, and meets the use requirements of security and protection.

Description

Technical Field

[0001] The present invention relates to the technical field of optical devices, and in particular to a zoom lens. Background Art

[0002] In recent years, in the field of security, zoom lenses have been widely used due to their advantages such as long shooting distance and large shooting angle. With the development of technology, cameras are gradually moving towards miniaturization and refinement, which also puts forward more stringent requirements for mainstream zoom lenses. At present, 1 / 1.8" chips have gradually become the mainstream chips on the market and have been more widely used, but traditional zoom lenses usually use 1 / 2.7" chips, which are difficult to use in a wide range of environments, and traditional zoom lenses have problems such as small aperture and infrared non-confocality. Therefore, it is necessary to develop a high-quality zoom lens with a small size, large aperture, infrared high and low temperature confocality, and the ability to work with a 1 / 1.8" chip. Summary of the invention

[0003] The invention provides a zoom lens which can realize full-band imaging and has a small size.

[0004] According to one aspect of the present invention, there is provided a zoom lens, comprising a focus lens group, a magnification lens group and a fixed lens group arranged in sequence from an object plane to an image plane along an optical axis; the fixed lens group is fixedly arranged, and the focus lens group and the magnification lens group are movably arranged along the optical axis direction;

[0005] The focusing lens group has a negative optical power, the variable power lens group has a positive optical power, and the fixed lens group has a positive optical power;

[0006] The focusing lens group includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence from the object plane to the image plane along the optical axis;

[0007] The variable power lens group includes a sixth lens, a seventh lens, an eighth lens, a ninth lens and a tenth lens arranged in sequence from the object plane to the image plane along the optical axis;

[0008] The fixed lens group includes an eleventh lens;

[0009] The first lens has negative optical power, the second lens has negative optical power or positive optical power, the third lens has negative optical power; the fourth lens has positive optical power; the fifth lens has negative optical power, the sixth lens has positive optical power, the seventh lens has negative optical power, the eighth lens has positive optical power, the ninth lens has negative optical power or positive optical power, the tenth lens has negative optical power and the eleventh lens has positive optical power.

[0010] Optionally, the first lens is a convexoconcave lens, the second lens is a convexoconcave lens, the fourth lens is a biconcave lens, the sixth lens is a biconvex lens, the seventh lens is a convexoconcave lens, the eighth lens is a biconvex lens, the ninth lens is a convexoconcave lens, the tenth lens is a convexoconcave lens, and the eleventh lens is a convexoconvex lens.

[0011] Optionally, the second lens, the fifth lens, the sixth lens, the ninth lens, the tenth lens and the eleventh lens are all aspherical lenses; and the first lens, the third lens, the fourth lens, the seventh lens and the eighth lens are all glass spherical lenses.

[0012] Optionally, the refractive index of the first lens is nd1, and the Abbe number is vd1; the refractive index of the third lens is nd3, and the Abbe number is vd3; the refractive index of the fifth lens is nd5, and the Abbe number is vd5; the refractive index of the sixth lens is nd6, and the Abbe number is vd6; the refractive index of the tenth lens is nd10, and the Abbe number is vd10, wherein:

[0013] 1.55≤nd1≤1.59;56.13≤vd1≤75.50;

[0014] 1.68≤nd3≤1.74;52.68≤vd3≤55.52;

[0015] 1.54≤nd5≤1.63; 24.64≤vd5≤55.99;

[0016] 1.50≤nd6≤1.61;57.97≤vd6≤81.61;

[0017] 1.54≤nd10≤1.66;20.38≤vd10≤53.81.

[0018] Optionally, the focal length of the focusing lens group is F1, the focal length of the variable magnification lens group is F2, the focal length of the fixed lens group is F3, and the focal length of the zoom lens at the wide-angle end is FW, wherein:

[0019] -2.906≤F1 / FW≤-2.662;

[0020] 2.272≤F2 / FW≤2.576;

[0021] 4.048≤F3 / FW≤7.581.

[0022] Optionally, the focal length of the zoom lens at the wide-angle end is FW, and the focal length of the zoom lens at the telephoto end is FT, wherein:

[0023] FT / FW≥5.

[0024] Optionally, the maximum movable distance of the focus lens group is S1, and the maximum movable distance of the variable magnification lens group is S2, wherein:

[0025] 0.888≤S1 / S2≤1.136.

[0026] Optionally, the third lens and the fourth lens are cemented to form a first cemented lens group, the focal length of the first cemented lens group is F34, the seventh lens and the eighth lens are cemented to form a second cemented lens group, the focal length of the second cemented lens group is F78, the focal length of the focusing lens group is F1, and the focal length of the variable magnification lens group is F2, wherein:

[0027] -70.754≤F34 / F1≤57.563;-5.537≤F78 / F2≤-2.379.

[0028] Optionally, the total optical length of the zoom lens is TTL, and the maximum movable distance of the zoom lens group is S2, wherein:

[0029] 2.700≤TTL / S2≤2.986.

[0030] Optionally, the zoom lens further includes an aperture;

[0031] The aperture stop is located in the optical path between the sixth lens and the seventh lens; or, the aperture stop is located in the optical path between the eighth lens and the ninth lens.

[0032] The technical solution of the embodiment of the present invention provides a three-component zoom lens, including a focus lens group, a variable magnification lens group and a fixed lens group arranged in sequence along the optical axis from the object plane to the image plane, and specifically uses 11 lenses, which is a small number of lenses, thereby helping to reduce the length of the lens. By reasonably matching the focus lens group, the variable magnification lens group, the fixed lens group and the focal length of each lens therein, the aberration can be well corrected to ensure the imaging effect. At the same time, the zoom lens has the advantages of small size and small distortion, meeting the needs of security use.

[0033] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. 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 these drawings without creative work.

[0035] Figure 1 A schematic diagram of the structure of a zoom lens at the wide-angle end provided in Embodiment 1 of the present invention;

[0036] Figure 2 A schematic diagram of the structure of the zoom lens at the telephoto end provided by the first embodiment of the present invention;

[0037] Figure 3 A vertical axis chromatic aberration curve of the zoom lens provided in the first embodiment of the present invention at the wide-angle end;

[0038] Figure 4 A light fan diagram of the zoom lens at the wide-angle end provided in the first embodiment of the present invention;

[0039] Figure 5 A modulation transfer function curve of the zoom lens provided in the first embodiment of the present invention at the wide-angle end in the visible light band;

[0040] Figure 6 A modulation transfer function curve of the zoom lens provided in the first embodiment of the present invention at the wide-angle end in the near-infrared band;

[0041] Figure 7 A vertical axis chromatic aberration curve of the zoom lens provided in the first embodiment of the present invention at the telephoto end;

[0042] Figure 8 A light fan diagram of the zoom lens at the telephoto end provided by the first embodiment of the present invention;

[0043] Fig. 9 A modulation transfer function curve of the zoom lens provided in the first embodiment of the present invention at the telephoto end in the visible light band;

[0044] Fig.10 A modulation transfer function curve of the zoom lens provided in the first embodiment of the present invention at the telephoto end in the near-infrared band;

[0045] Fig.11 A schematic diagram of the structure of a zoom lens at the wide-angle end provided in Embodiment 2 of the present invention;

[0046] Fig.12 A schematic diagram of the structure of a zoom lens at the telephoto end provided by Embodiment 2 of the present invention;

[0047] Fig.13A vertical axis chromatic aberration curve of the zoom lens provided in the second embodiment of the present invention at the wide-angle end;

[0048] Fig.14 A light fan diagram of the zoom lens at the wide-angle end provided in the second embodiment of the present invention;

[0049] Fig.15 A modulation transfer function curve of the zoom lens provided in the second embodiment of the present invention at the wide-angle end in the visible light band;

[0050] Fig.16 A modulation transfer function curve of the zoom lens provided in the second embodiment of the present invention at the wide-angle end in the near-infrared band;

[0051] Fig.17 A vertical axis chromatic aberration curve of the zoom lens provided in the second embodiment of the present invention at the telephoto end;

[0052] Fig.18 A light fan diagram of the zoom lens at the telephoto end provided by the second embodiment of the present invention;

[0053] Fig.19 A modulation transfer function curve of the zoom lens provided in the second embodiment of the present invention at the telephoto end in the visible light band;

[0054] Fig. 20 A modulation transfer function curve of the zoom lens provided in the second embodiment of the present invention at the telephoto end in the near-infrared band;

[0055] Fig.21 A schematic diagram of the structure of a zoom lens at the wide-angle end provided in Embodiment 3 of the present invention;

[0056] Fig. 22 A schematic diagram of the structure of a zoom lens at the telephoto end provided by Embodiment 3 of the present invention;

[0057] Fig.23 A vertical axis chromatic aberration curve of the zoom lens provided in Embodiment 3 of the present invention at the wide-angle end;

[0058] Fig.24 A light fan diagram of the zoom lens at the wide-angle end provided in the third embodiment of the present invention;

[0059] Fig.25 A modulation transfer function curve of the zoom lens provided in the third embodiment of the present invention at the wide-angle end in the visible light band;

[0060] Fig.26 A modulation transfer function curve of the zoom lens provided in the third embodiment of the present invention at the wide-angle end in the near-infrared band;

[0061] Fig. 27 A vertical axis chromatic aberration curve of the zoom lens at the telephoto end provided by the third embodiment of the present invention;

[0062] Fig.28 A light fan diagram of the zoom lens at the telephoto end provided by the third embodiment of the present invention;

[0063] Fig.29 A modulation transfer function curve of the zoom lens provided in the third embodiment of the present invention at the telephoto end in the visible light band;

[0064] Fig.30 This is a modulation transfer function curve of the zoom lens provided in the third embodiment of the present invention at the telephoto end in the near-infrared band. DETAILED DESCRIPTION

[0065] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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 should fall within the scope of protection of the present invention.

[0066] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0067] Embodiment 1

[0068] Figure 1 This is a schematic structural diagram of a zoom lens at a wide-angle end provided in Embodiment 1 of the present invention. Figure 2 The structure diagram of the zoom lens at the telephoto end provided by the first embodiment of the present invention is as follows: Figure 1 and 2As shown, the zoom lens comprises a focus lens group 10, a variable magnification lens group 11 and a fixed lens group 12 which are arranged in sequence from the object plane to the image plane along the optical axis; the fixed lens group 12 is fixedly arranged, and the focus lens group 10 and the variable magnification lens group 11 are movable along the optical axis; the focus lens group 10 has a negative optical focal length, the variable magnification lens group 11 has a positive optical focal length, and the fixed lens group 12 has a positive optical focal length; the focus lens group 10 comprises a first lens 101, a second lens 102, a third lens 103, a fourth lens 104 and a fifth lens 105 which are arranged in sequence from the object plane to the image plane along the optical axis; the variable magnification lens group 11 comprises a sixth lens which is arranged in sequence from the object plane to the image plane along the optical axis 106, a seventh lens 107, an eighth lens 108, a ninth lens 109 and a tenth lens 110; the fixed lens group 12 includes an eleventh lens 111; the first lens 101 has a negative optical focal power, the second lens 102 has a negative optical focal power or a positive optical focal power, the third lens 103 has a negative optical focal power; the fourth lens 104 has a positive optical focal power; the fifth lens 105 has a negative optical focal power, the sixth lens 106 has a positive optical focal power, the seventh lens 107 has a negative optical focal power, the eighth lens 108 has a positive optical focal power, the ninth lens 109 has a negative optical focal power or a positive optical focal power, the tenth lens 110 has a negative optical focal power and the eleventh lens 111 has a positive optical focal power.

[0069] In the zoom lens provided in this embodiment, the focus lens group 10, the variable magnification lens group 11 and the fixed lens group 12 can be arranged in a lens barrel ( Figure 1 The fixed lens group 12 is fixed in the lens barrel, and the focus lens group 10 and the variable magnification lens group 11 can move back and forth along the optical axis in the lens barrel. Through the joint movement of the focus lens group 10 and the variable magnification lens group 11, the focal length of the zoom lens can be continuously changed from wide angle to telephoto, ensuring that the zoom lens has high image quality at each focus position while ensuring the miniaturization of the zoom lens.

[0070] It can be understood that in the process of zooming by moving the focusing lens group 10 and the variable magnification lens group 11, the zoom lens is located at the wide-angle end when the focal length is shortest, and is located at the telephoto end when the focal length is longest. At the wide-angle end and the telephoto end, the zoom lens has different focal lengths and optical focal powers, and also has different lengths or shapes.

[0071] Furthermore, the 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 optical system to deflect light. The larger the absolute value of the focal length, the stronger the ability to bend light, and the smaller the absolute value of the focal length, the weaker the ability to bend light. When the focal length is a positive number, the refraction of light is convergent; when the focal length is a negative number, the refraction of light is divergent. The 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).

[0072] In this embodiment, by setting the focusing lens group 10 to have a negative optical focal length, the variable magnification lens group 11 to have a positive optical focal length, and the fixed lens group 12 to have a positive optical focal length, the optical focal lengths of the focusing lens group 10, the variable magnification lens group 11 and the fixed lens group 12 cooperate with each other, which can compensate for the aberrations caused by the zooming movement of the focusing lens group 10 and the variable magnification lens group 11, thereby ensuring the clarity of the image under different focal length states.

[0073] Further, such as Figure 1 and Figure 2 As shown, the focusing lens group 10 includes a first lens 101 with negative focal power, a second lens 102 with negative or positive focal power, a third lens 103 with negative focal power, a fourth lens 104 with positive focal power, and a fifth lens 105 with negative focal power, which are arranged in sequence from the object plane to the image plane along the optical axis; the variable power lens group 11 includes a sixth lens 106 with positive focal power, a seventh lens 107 with negative focal power, an eighth lens 108 with positive focal power, a ninth lens 109 with negative or positive focal power, and a tenth lens 110 with negative focal power, which are arranged in sequence from the object plane to the image plane along the optical axis; and the fixed lens group 12 includes an eleventh lens 111 with positive focal power. The use of the focusing lens group 10 with negative focal power and the sixth lens 106 with positive focal power at the front end of the aperture can ensure that a larger light aperture is generated after the light passes through, increase the aperture number of the optical system, and meet the use requirements under different conditions. By rationally allocating the optical power of each lens, it is beneficial to better correct aberrations and ensure the clarity of images at different focal lengths.

[0074] The zoom lens provided in the embodiment of the present invention uses only 11 lenses, which is a small number of lenses, thus helping to reduce the length of the lens. At the same time, by reasonably matching the focal lengths of the 11 lenses, aberrations can be well corrected, and a zoom lens with full focal length confocality can be realized, which can be applied to 1 / 1.8" large-surface photosensitive chips, thereby meeting a wide range of security monitoring needs.

[0075] Furthermore, the third lens 103 and the fourth lens 104 in the zoom lens form a double-cemented lens group, and the seventh lens 107 and the eighth lens 108 form a double-cemented lens group, which can reduce the air gap between the third lens 103 and the fourth lens 104 and the air gap between the seventh lens 107 and the eighth lens 108, thereby further reducing the total length of the lens. In addition, the cemented lens can be used to minimize or eliminate chromatic aberration, so that various aberrations of the zoom lens can be fully corrected, and the resolution can be improved, and the optical performance such as distortion and CRA can be optimized under the premise of compact structure; and the light loss caused by reflection between lenses can be reduced, and the illumination can be increased, thereby improving the image quality and the clarity of the lens imaging. In addition, the use of the cemented lens can also reduce the assembly parts between the two lenses, simplify the assembly procedures in the lens manufacturing process, reduce costs, and reduce the tolerance sensitivity problems such as tilt / eccentricity caused by the lens unit during the assembly process.

[0076] In addition, the cemented lens used in the focusing lens group 10 can also correct the high-level chromatic aberration and aberration of the lens, control the aberration balance of each group, ensure that no serious aberration will be generated when the light enters the structure behind the aperture, and improve the imaging quality of the optical system.

[0077] The aspherical lenses, cemented lenses, etc. of the variable-power lens group 11 and the fixed lens group 12 can correct the aberration at the rear end of the lens, and cooperate with the lens group at the front end of the aperture to stabilize the imaging quality of the optical system.

[0078] Furthermore, a plane glass 112 is provided along the object plane to the image plane; the plane glass 112 is located on the image side of the eleventh lens 111, and the plane glass 112 can protect the photosensitive chip in the imaging sensor, wherein the imaging chip is used to convert the light signal collected by the zoom lens into an electrical signal, thereby ensuring the imaging effect of the zoom lens.

[0079] In summary, the embodiment of the present invention provides a three-component zoom lens, including a focus lens group, a variable magnification lens group and a fixed lens group arranged in sequence from the object plane to the image plane along the optical axis, and specifically uses 11 lenses, which is a small number of lenses, thereby helping to reduce the length of the lens. By reasonably matching the focus lens group, the variable magnification lens group and the fixed lens group and the focal length of each lens therein, aberrations can be well corrected to ensure the clarity of the image under different focal lengths. At the same time, the zoom lens has the advantages of small size, ultra-wide angle and large aperture, meeting the needs of security monitoring.

[0080] Optionally, the first lens 101 is a convexo-concave lens, the second lens 102 is a convexo-concave lens, the fourth lens 104 is a biconcave lens, the sixth lens 106 is a biconvex lens, the seventh lens 107 is a convexo-concave lens, the eighth lens 108 is a biconvex lens, the ninth lens 109 is a convexo-concave lens, the tenth lens 110 is a convexo-concave lens, and the eleventh lens 111 is a concave-convex lens. By reasonably setting the surface shape of each lens, it is ensured that the optical power of each lens meets the optical power requirements in the above embodiment, and the entire zoom lens structure can be compact and the zoom lens has a high degree of integration.

[0081] Optionally, the second lens 102 , the fifth lens 105 , the sixth lens 106 , the ninth lens 109 , the tenth lens 110 and the eleventh lens 111 are all aspherical lenses; and the first lens 101 , the third lens 103 , the fourth lens 104 , the seventh lens 107 and the eighth lens 108 are all glass spherical lenses.

[0082] In this embodiment, the second lens 102, the fifth lens 105, the sixth lens 106, the ninth lens 109, the tenth lens 110 and the eleventh lens 111 are aspherical lenses, which can correct off-axis aberrations, including field curvature, coma, astigmatism, etc. The second lens 102, the fifth lens 105, the sixth lens 106, the ninth lens 109, the tenth lens 110 and the eleventh lens 111 can adopt glass aspherical lenses to better correct chromatic aberration and aberration and improve image quality. In addition, the eleventh lens 111 in the fixed lens group 12 adopts an aspherical lens. Before the light reaches the image plane, the use of aspherical lenses can well correct aberrations and reduce CRA (chief ray angle), which can effectively improve image quality and can match most 1 / 1.8" chips on the market.

[0083] Furthermore, the second lens 102, the fifth lens 105, the sixth lens 106, the ninth lens 109, the tenth lens 110 and the eleventh lens 111 may also be plastic aspheric lenses, but are not limited thereto. Since the cost of lenses made of plastic is much lower than that of lenses made of glass, the cost of the zoom lens can be reduced. At the same time, the two types of materials, glass and plastic, can compensate for each other, balance high and low temperatures and reduce the total length of the lens, so that the zoom lens has the characteristics of stable high and low temperature performance, improves the environmental adaptability of the zoom lens, and can meet the use conditions of -40°C-80°C.

[0084] The material of the plastic aspheric lens can be various plastics known to those skilled in the art, and the material of the glass spherical lens and the glass aspheric lens can be various types of glass known to those skilled in the art, which will not be elaborated or limited in the embodiments of the present invention.

[0085] Optionally, the refractive index of the first lens 101 is nd1, and the Abbe number is vd1; the refractive index of the third lens 103 is nd3, and the Abbe number is vd3; the refractive index of the fifth lens 105 is nd5, and the Abbe number is vd5; the refractive index of the sixth lens 106 is nd6, and the Abbe number is vd6; the refractive index of the tenth lens 110 is nd10, and the Abbe number is vd10, wherein: 1.55≤nd1≤1. 59; 56.13≤vd1≤75.50; 1.68≤nd3≤1.74; 52.68≤vd3≤55.52; 1.54≤nd5≤1.63; 24.64≤vd5≤55.99; 1.50≤nd6≤1.61; 57.97≤vd6≤81.61; 1.54≤nd10≤1.66; 20.38≤vd10≤53.81.

[0086] The refractive index is the ratio of the speed of light in a vacuum to the speed of light in the medium. It is mainly used to describe the material's ability to refract light. Different materials have different refractive indices. The Abbe number is an index used to represent the dispersion ability of a transparent medium. The more severe the dispersion of the medium, the smaller the Abbe number; conversely, the less dispersion of the medium, the larger the Abbe number.

[0087] In order to ensure that the zoom optical system can image stably at the full focal length, it is usually necessary to separately eliminate chromatic aberration and control aberration of the fixed lens group 12 to prevent chromatic aberration and aberration from accumulating too much and being difficult to control after entering the moving lens group, thereby affecting the image quality. The first lens 101 and the third lens 103 use the materials of the above-mentioned lenses to control the chromatic aberration and aberration entering the focusing lens group 10 within a reasonable range, and prevent them from being over-magnified during the movement of the focusing lens group 10, which makes it difficult to correct them later. The fifth lens 105 and the sixth lens 106 use the materials of the above-mentioned lenses to correct the chromatic aberration and aberration generated by the entire lens, and control them within a reasonable range before the light enters the image plane. In addition, the aspherical lens has a good ability to control the high-level aberration of the optical system. The fifth lens 105, the sixth lens 106 and the tenth lens 110 use aspherical lenses to further reduce the high-level aberration when the light enters the image plane, so that the image quality can be further improved to meet the needs of 4K imaging.

[0088] In addition, the properties of glass lenses are not sensitive to temperature. Lenses using all-glass lenses have more uniform performance under different temperature conditions, and have the characteristics of stable high and low temperature performance, which improves the environmental adaptability of zoom optical systems; the introduction of glass aspherical lenses also corrects the chromatic aberration and high-order aberrations of lenses to a large extent, and has a wider range of options than plastic aspherical lenses, and can use more diverse results in structural selection, thereby improving the market competitiveness of lenses. In addition, the material of the glass spherical lens is various types of glass known to those skilled in the art, and the embodiments of the present invention will not be described in detail.

[0089] Optionally, the focal length of the focusing lens group 10 is F1, the focal length of the variable magnification lens group 11 is F2, the focal length of the fixed lens group 12 is F3, and the focal length of the zoom lens at the wide-angle end is FW, wherein: -2.906≤F1 / FW≤-2.662; 2.272≤F2 / FW≤2.576; 4.048≤F3 / FW≤7.581. Among them, the focal powers of the focusing lens group 10, the variable magnification lens group 11 and the fixed lens group 12 are matched in a negative-positive-positive manner to achieve a reasonable match of the focal powers, and at the same time, the ratio of the focal lengths of the focusing lens group 10, the variable magnification lens group 11 and the fixed lens group 12 to the focal length of the zoom lens at the wide-angle end is reasonably set, so that when the light passes smoothly through the lens, the high-order aberrations can be corrected to a great extent, and the imaging quality is improved. At the same time, it is ensured that the zoom lens has a high resolution.

[0090] Optionally, the focal length of the zoom lens at the wide-angle end is FW, and the focal length of the zoom lens at the telephoto end is FT, where: FT / FW ≥ 5. The diaphragm position of the zoom lens at different focal lengths remains consistent relative to the image plane position, and the diaphragm diameter is the same at different focal lengths. By controlling the focal length ratio of the zoom lens at the wide-angle end and at the telephoto end, the distortion can be controlled within a reasonable small range while ensuring the zoom range and a large target surface, thereby meeting the small distortion requirement of the zoom lens.

[0091] Optionally, the maximum movable distance of the focus lens group 10 is S1, and the maximum movable distance of the zoom lens group 11 is S2, wherein: 0.888≤S1 / S2≤1.136. By controlling the moving distances of the focus lens group 10 and the zoom lens group 11, the lens volume is minimized.

[0092] Optionally, the third lens 103 and the fourth lens 104 are glued together to form a first glued lens group, the focal length of the first glued lens group is F34, the seventh lens 107 and the eighth lens 108 are glued together to form a second glued lens group, the focal length of the second glued lens group is F78, the focal length of the focus lens group 10 is F1, and the focal length of the zoom lens group 11 is F2, wherein: -70.754≤F34 / F1≤57.563; -5.537≤F78 / F2≤-2.379. By using the above focal length combination in the focus lens group 10 of the zoom lens, the light can pass through the front end of the lens smoothly, and before the light enters the zoom lens group 11, the chromatic aberration and aberration generated by the front end are reduced, further improving the image quality. During the zooming process of the zoom lens, the zoom lens group 11 is responsible for zooming the optical system with a changed focal length. The use of aspherical lenses and cemented lenses can correct the chromatic aberration and higher-order aberrations generated in the zoom lens group 11, greatly reducing the aberration pressure of other lens groups at different focal lengths, thereby achieving focusing of the optical system at the full focal length.

[0093] Optionally, the total optical length of the zoom lens is TTL, and the maximum movable distance of the zoom lens group 11 is S2, wherein: 2.700≤TTL / S2≤2.986. The limitation of the zoom lens group 11 and the total length of the lens can compress the lens space, ensuring that the required imaging quality and zoom degree are met under the condition of small lens volume.

[0094] Optionally, the zoom lens further includes an aperture STO; the aperture STO is located in the optical path between the sixth lens 106 and the seventh lens 107; or, the aperture STO is located in the optical path between the eighth lens 108 and the ninth lens 109.

[0095] Among them, by adding an aperture STO, the propagation direction of the light beam can be adjusted, which is beneficial to improving the imaging quality. The aperture STO can be located in the optical path between the sixth lens 106 and the seventh lens 107, or the aperture STO can be located between the eighth lens 108 and the ninth lens 109, but the embodiment of the present invention does not limit the specific setting position of the aperture. The zoom lens is confocal in the full band of 436nm-850nm and has high image quality, which meets the use requirements in more situations. Controlling the zoom lens to keep the aperture position consistent relative to the image plane position at different focal lengths and the aperture diameter at different focal lengths The same can reduce the aperture range from the structure, ensure that the movable group of the lens has a longer travel distance, achieve a higher imaging magnification or reduce the volume, and meet the use requirements under different conditions.

[0096] In summary, the zoom lens provided by the present invention, by reasonably allocating the optical focal length, can meet the imaging requirements in the full band of 436nm-850nm with a 1 / 1.8" large target surface photosensitive chip, and realize a zoom lens with a large aperture and infrared high and low temperature confocal.

[0097] For example, Table 1 describes in detail the specific optical and physical parameters of each lens in the zoom lens provided in Example 1 of the present invention in a feasible implementation manner. The zoom lens in Table 1 corresponds to Figure 1 and Figure 2 Zoom lens shown.

[0098] Table 1 Design values ​​of optical physical parameters of zoom lens

[0099]

[0100]

[0101] Among them, the surface numbers are numbered according to the surface order of each lens, for example, surface number 1 represents the object side surface of the first lens 101, surface number 2 represents the image side surface of the first lens 101, and so on; the radius of curvature represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side, INF represents that the radius of curvature is infinite, and PL represents that the surface is a plane; the thickness represents the central axial distance from the current surface to the next surface, and the units of the radius of curvature and thickness are both millimeters (mm); material (nd) is the refractive index, which represents the ability of the material between the current surface and the next surface to deflect light, and a space represents that the current position is air, and the refractive index is 1; material (vd) is the dispersion coefficient, which represents the dispersion characteristics of the material between the current surface and the next surface to light, and a space represents that the current position is air; STO represents the aperture.

[0102] Table 2 shows the values ​​of the zoom intervals in Table 1.

[0103] Table 2 Zoom intervals at the wide-angle and telephoto ends of zoom lenses

[0104] Wide-angle end Telephoto end Zoom interval 1 24.019 0.414 Zoom interval 2 0.310 21.090

[0105] The shape equation Z of its aspherical surface satisfies:

[0106]

[0107] Where Z is the axial distance from the surface at a height r perpendicular to the optical axis to the vertex of the surface along the optical axis; c represents the curvature at the vertex of the aspheric surface; a4, a6, a8, a 10 、a 12 、a 14 , corresponding to the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, and fourteenth-order high-order aspheric coefficients of the aspheric surface, a i r i The combination becomes the high-order terms corresponding to the aspherical surface.

[0108] Exemplarily, Table 3 describes in detail the aspheric coefficients of each lens in the first embodiment in a feasible implementation manner.

[0109] Table 3 Design values ​​of aspheric coefficients of each lens in zoom lens

[0110]

[0111]

[0112] Among them, -1.5670729949802E-05 means that the coefficient a4 of face number 3 is -1.5670729949802*10 -4 , and so on.

[0113] The zoom lens provided in this embodiment achieves the following specific parameters:

[0114] Table 4 Specific parameters of zoom lens

[0115]

[0116] Furthermore, Figure 3 The vertical axis chromatic aberration curve of the zoom lens provided in the first embodiment of the present invention at the wide-angle end is as follows: Figure 3 As shown. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertex in the vertical axis represents the maximum pupil radius; the main wavelength uses 546.074nm, and the horizontal direction represents the offset relative to the main wavelength in micrometers (um). Figure 3 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within a small range, indicating that the vertical chromatic aberration of the zoom lens at the wide-angle end is well controlled and can meet the application requirements under normal conditions.

[0117] Figure 4 This is a light fan diagram of the zoom lens provided in the first embodiment of the present invention at the wide-angle end, such as Figure 4 As shown. In a single figure, the horizontal axis is the normalized beam aperture, and the vertical axis is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis, and all light rays in the field of view are focused on the same point on the image plane; the vertical axis in a single image can also be expressed as the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. Figure 4 It can be seen that in this zoom lens, each wavelength is well close to the horizontal axis in each field of view, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, the curves of each color are not obviously scattered, indicating that this zoom lens also has good correction for chromatic aberration, meeting the use requirements of this zoom lens.

[0118] Figure 5 The modulation transfer function curve of the zoom lens provided in the first embodiment of the present invention at the wide-angle end in the visible light band is as follows: Figure 5 The vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 435.8nm to 656.3nm, and the main wavelength is 546.074nm. Figure 5 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. When the value is 125 line pairs / mm, the transfer function is basically above 0.3, indicating that the image quality of the zoom lens at the wide-angle end is well controlled and meets the use requirements of 4k cameras.

[0119] Figure 6The modulation transfer function curve of the zoom lens provided in the first embodiment of the present invention at the wide-angle end in the near-infrared band is as follows: Figure 6 The vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated infrared band range is 830nm~870nm, and the main wavelength is 850nm. Figure 6 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. When the value is 125 line pairs / mm, the transfer function is basically above 0.3, indicating that the image quality of the zoom lens at the wide-angle end is well controlled and meets the use requirements of 4k cameras.

[0120] Figure 7 The vertical axis chromatic aberration curve of the zoom lens provided in the first embodiment of the present invention at the telephoto end is as follows: Figure 7 As shown. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertex in the vertical axis represents the maximum pupil radius; the main wavelength uses 546.074nm, and the horizontal direction represents the offset relative to the main wavelength in micrometers (um). Figure 7 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within a small range, indicating that the vertical chromatic aberration of the zoom lens at the telephoto end is well controlled and can meet the application requirements under normal conditions.

[0121] Figure 8 This is a light fan diagram of the zoom lens provided in the first embodiment of the present invention at the telephoto end, such as Figure 8 As shown. In a single figure, the horizontal axis is the normalized beam aperture, and the vertical axis is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis, and all light rays in the field of view are focused on the same point on the image plane; the vertical axis in a single image can also be expressed as the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. Figure 8 It can be seen that the zoom lens is close to the horizontal axis at each wavelength in each field of view, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, the curves of each color are not obviously scattered, indicating that the zoom lens also has good correction for chromatic aberration, meeting the use requirements of the zoom lens.

[0122] Fig. 9 The modulation transfer function curve of the zoom lens provided in the first embodiment of the present invention at the telephoto end in the visible light band is as follows: Fig. 9 The vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 435.8nm to 656.3nm, and the main wavelength is 546.074nm. Fig. 9It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. When the value is 125 line pairs / mm, the transfer function is basically above 0.4, indicating that the image quality of the zoom lens at the telephoto end is well controlled and meets the use requirements of 4k cameras.

[0123] Fig.10 The modulation transfer function curve of the zoom lens provided in the first embodiment of the present invention at the telephoto end in the near infrared band is as follows: Fig.10 The vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated infrared band range is 830nm~870nm, and the main wavelength is 850nm. Fig.10 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range, among which the transfer function at 125 line pairs / mm is basically above 0.3, and the MTF of each field of view is close to the diffraction limit. This shows that the image quality of this zoom lens at the telephoto end is well controlled and meets the use requirements of 4k cameras.

[0124] Embodiment 2

[0125] Fig.11 This is a schematic diagram of the structure of the zoom lens at the wide-angle end provided in the second embodiment of the present invention. Fig.12 This is a schematic diagram of the structure of the zoom lens at the telephoto end provided by the second embodiment of the present invention, as shown in FIG. Fig.11 and Fig.12As shown, the zoom lens comprises a focus lens group 10, a variable magnification lens group 11 and a fixed lens group 12 which are arranged in sequence from the object plane to the image plane along the optical axis; the fixed lens group 12 is fixedly arranged, and the focus lens group 10 and the variable magnification lens group 11 are movable along the optical axis; the focus lens group 10 has a negative optical focal length, the variable magnification lens group 11 has a positive optical focal length, and the fixed lens group 12 has a positive optical focal length; the focus lens group 10 comprises a first lens 201, a second lens 202, a third lens 203, a fourth lens 204 and a fifth lens 205 which are arranged in sequence from the object plane to the image plane along the optical axis; the variable magnification lens group 11 comprises a sixth lens which is arranged in sequence from the object plane to the image plane along the optical axis 206, the seventh lens 207, the eighth lens 208, the ninth lens 209 and the tenth lens 210; the fixed lens group 12 includes the eleventh lens 211; the first lens 201 has a negative focal power, the second lens 202 has a negative focal power or a positive focal power, and the third lens 203 has a negative focal power; the fourth lens 204 has a positive focal power; the fifth lens 205 has a negative focal power, the sixth lens 206 has a positive focal power, the seventh lens 207 has a negative focal power, the eighth lens 208 has a positive focal power, the ninth lens 209 has a negative focal power or a positive focal power, the tenth lens 210 has a negative focal power and the eleventh lens 211 has a positive focal power. The aperture STO is located in the optical path between the eighth lens and the ninth lens 209. The zoom lens includes a doublet lens group consisting of the second lens 202 and the third lens 203, and a doublet lens group consisting of the sixth lens 206 and the seventh lens 207.

[0126] For example, Table 5 describes in detail the specific optical and physical parameters of each lens in the zoom lens provided in Example 2 of the present invention in a feasible implementation manner. The zoom lens in Table 5 corresponds to Fig.11 and Fig.12 Zoom lens shown.

[0127] Table 5 Design values ​​of optical physical parameters of zoom lens

[0128]

[0129]

[0130] Among them, the surface numbers are numbered according to the surface order of each lens, for example, surface number 1 represents the object side surface of the first lens 201, surface number 2 represents the image side surface of the first lens 201, and so on; the radius of curvature represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side, INF represents that the radius of curvature is infinite, and PL represents that the surface is a plane; the thickness represents the central axial distance from the current surface to the next surface, and the units of the radius of curvature and thickness are both millimeters (mm); material (nd) is the refractive index, which represents the ability of the material between the current surface and the next surface to deflect light, and a space represents that the current position is air, and the refractive index is 1; material (vd) is the dispersion coefficient, which represents the dispersion characteristics of the material between the current surface and the next surface to light, and a space represents that the current position is air; STO represents the aperture.

[0131] Table 6 shows the numerical values ​​of the zoom intervals in Table 5.

[0132] Table 6 Zoom intervals at the wide-angle and telephoto ends of zoom lenses

[0133] Wide-angle end Telephoto end Zoom interval 1 20.602 0.200 Zoom interval 2 0.304 23.268

[0134] Its aspherical surface shape equation Z satisfies:

[0135]

[0136] Where Z is the axial distance from the surface at a height r perpendicular to the optical axis to the vertex of the surface along the optical axis; c represents the curvature at the vertex of the aspheric surface; a4, a6, a8, a 10 、a 12 、a 14 , corresponding to the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, and fourteenth-order high-order aspheric coefficients of the aspheric surface, a i r i The combination becomes the high-order terms corresponding to the aspherical surface.

[0137] Exemplarily, Table 7 describes in detail the aspheric coefficients of each lens in the second embodiment in a feasible implementation manner.

[0138] Table 7 Design values ​​of aspheric coefficients of each lens in zoom lens

[0139]

[0140]

[0141] Among them, -1.0842089226360E-05 means that the coefficient a4 of face number 12 is -1.0842089226360*10 -5 , and so on.

[0142] The zoom lens provided in this embodiment achieves the following specific parameters:

[0143] Table 8 Specific parameters of zoom lens

[0144]

[0145] Furthermore, Fig.13 The vertical axis chromatic aberration curve of the zoom lens provided in the second embodiment of the present invention at the wide-angle end is as follows: Fig.13 As shown. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertex in the vertical axis represents the maximum pupil radius; the main wavelength uses 546.074nm, and the horizontal direction represents the offset relative to the main wavelength in micrometers (um). Fig.13 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within a small range, indicating that the vertical chromatic aberration of the zoom lens at the wide-angle end is well controlled and can meet the application requirements under normal conditions.

[0146] Fig.14 This is a light fan diagram of the zoom lens at the wide-angle end provided by the second embodiment of the present invention, such as Fig.14 As shown. In a single figure, the horizontal axis is the normalized beam aperture, and the vertical axis is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis, and all light rays in the field of view are focused on the same point on the image plane; the vertical axis in a single image can also be expressed as the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. Fig.14 It can be seen that in this zoom lens, each wavelength is well close to the horizontal axis in each field of view, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, the curves of each color are not obviously scattered, indicating that this zoom lens also has good correction for chromatic aberration, meeting the use requirements of this zoom lens.

[0147] Fig.15 The modulation transfer function curve of the zoom lens provided in the second embodiment of the present invention at the wide-angle end in the visible light band is as follows: Fig.15 The vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 435.8nm to 656.3nm, and the main wavelength is 546.074nm. Fig.15 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. When the value is 125 line pairs / mm, the transfer function is basically above 0.3, indicating that the image quality of the zoom lens at the wide-angle end is well controlled and meets the use requirements of 4k cameras.

[0148] Fig.16The modulation transfer function curve of the zoom lens provided in the second embodiment of the present invention at the wide-angle end in the near-infrared band is as follows: Fig.16 The vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated infrared band range is 830nm~870nm, and the main wavelength is 850nm. Fig.16 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. When the value is 125 line pairs / mm, the transfer function is basically above 0.3, indicating that the image quality of the zoom lens at the wide-angle end is well controlled and meets the use requirements of 4k cameras.

[0149] Fig.17 The vertical axis chromatic aberration curve of the zoom lens provided in the second embodiment of the present invention at the telephoto end is as follows: Fig.17 As shown. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertex in the vertical axis represents the maximum pupil radius; the main wavelength uses 546.074nm, and the horizontal direction represents the offset relative to the main wavelength in micrometers (um). Fig.17 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within a small range, indicating that the vertical chromatic aberration of the zoom lens at the telephoto end is well controlled and can meet the application requirements under normal conditions.

[0150] Fig.18 This is a light fan diagram of the zoom lens at the telephoto end provided by the second embodiment of the present invention, such as Fig.18 As shown. In a single figure, the horizontal axis is the normalized beam aperture, and the vertical axis is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis, and all light rays in the field of view are focused on the same point on the image plane; the vertical axis in a single image can also be expressed as the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. Fig.18 It can be seen that the zoom lens is close to the horizontal axis at each wavelength in each field of view, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, the curves of each color are not obviously scattered, indicating that the zoom lens also has good correction for chromatic aberration, meeting the use requirements of the zoom lens.

[0151] Fig.19 The modulation transfer function curve of the zoom lens provided in the second embodiment of the present invention at the telephoto end in the visible light band is as follows: Fig.19 The vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 435.8nm to 656.3nm, and the main wavelength is 546.074nm. Fig.19It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. When the value is 125 line pairs / mm, the transfer function is basically above 0.4, indicating that the image quality of the zoom lens at the telephoto end is well controlled and meets the use requirements of 4k cameras.

[0152] Fig. 20 The modulation transfer function curve of the zoom lens provided in the second embodiment of the present invention at the telephoto end in the near infrared band is as follows: Fig. 20 The vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated infrared band range is 830nm~870nm, and the main wavelength is 850nm. Fig. 20 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. When the line pair is 125 / mm, the transfer function is basically above 0.25, and the MTF of each field of view is close to the diffraction limit. This shows that the image quality of the zoom lens at the telephoto end is well controlled and meets the use requirements of 4k cameras.

[0153] Embodiment 3

[0154] Fig.21 This is a schematic diagram of the structure of the zoom lens at the wide-angle end provided in Embodiment 3 of the present invention. Fig. 22 This is a schematic diagram of the structure of the zoom lens at the telephoto end provided by the third embodiment of the present invention, as shown in FIG. Fig.21 and Fig. 22As shown, the zoom lens comprises a focus lens group 10, a variable magnification lens group 11 and a fixed lens group 12 which are arranged in sequence from the object plane to the image plane along the optical axis; the fixed lens group 12 is fixedly arranged, and the focus lens group 10 and the variable magnification lens group 11 are movable along the optical axis; the focus lens group 10 has a negative optical focal length, the variable magnification lens group 11 has a positive optical focal length, and the fixed lens group 12 has a positive optical focal length; the focus lens group 10 comprises a first lens 301, a second lens 2, a third lens 303, a fourth lens 304 and a fifth lens 305 which are arranged in sequence from the object plane to the image plane along the optical axis; the variable magnification lens group 11 comprises a sixth lens which is arranged in sequence from the object plane to the image plane along the optical axis The first lens 301 has a negative focal power, the second lens 302 has a negative focal power or a positive focal power, and the third lens 303 has a negative focal power; the fourth lens 304 has a positive focal power; the fifth lens 305 has a negative focal power, the sixth lens 306 has a positive focal power, the seventh lens 307 has a negative focal power, the eighth lens 308 has a positive focal power, the ninth lens 309 has a negative focal power or a positive focal power, the tenth lens 310 has a negative focal power, and the eleventh lens 311 has a positive focal power. The stop STO is located in the optical path between the eighth lens 308 and the ninth lens 309. The zoom lens includes a doublet lens group consisting of the second lens 302 and the third lens 303, and a doublet lens group consisting of the sixth lens 306 and the seventh lens 307.

[0155] For example, Table 9 describes in detail the specific optical and physical parameters of each lens in the zoom lens provided in Example 3 of the present invention in a feasible implementation manner. The zoom lens in Table 9 corresponds to Fig.17 and Fig.18 Zoom lens shown.

[0156] Table 9 Design values ​​of optical physical parameters of zoom lens

[0157]

[0158]

[0159] Among them, the surface numbers are numbered according to the surface order of each lens, for example, surface number 1 represents the object side surface of the third lens 301, surface number 2 represents the image side surface of the third lens 301, and so on; the radius of curvature represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side, INF represents that the radius of curvature is infinite, and PL represents that the surface is a plane; the thickness represents the central axial distance from the current surface to the next surface, and the units of the radius of curvature and thickness are both millimeters (mm); material (nd) is the refractive index, which represents the ability of the material between the current surface and the next surface to deflect light, and a space represents that the current position is air, and the refractive index is 1; material (vd) is the dispersion coefficient, which represents the dispersion characteristics of the material between the current surface and the next surface to light, and a space represents that the current position is air; STO represents the aperture.

[0160] Table 10 shows the numerical values ​​of the zoom intervals in Table 9.

[0161] Table 10 Zoom intervals at the wide-angle and telephoto ends of zoom lenses

[0162] Wide-angle end Telephoto end Zoom interval 1 22.280 0.204 Zoom interval 2 0.536 22.625

[0163] Its aspherical surface shape equation Z satisfies:

[0164]

[0165] Where Z is the axial distance from the surface at a height r perpendicular to the optical axis to the vertex of the surface along the optical axis; c represents the curvature at the vertex of the aspheric surface; a4, a6, a8, a 10 、a 12 、a 14 , corresponding to the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, and fourteenth-order high-order aspheric coefficients of the aspheric surface, a i r i The combination becomes the high-order terms corresponding to the aspherical surface.

[0166] Exemplarily, Table 11 describes in detail the aspheric coefficients of each lens in the third embodiment in a feasible implementation manner.

[0167] Table 11 Design values ​​of aspheric coefficients of each lens in zoom lens

[0168]

[0169]

[0170] Among them, 2.0175518444731E-04 means that the coefficient a4 of face number 13 is 2.0175518444731*10 -4 , and so on.

[0171] The zoom lens provided in this embodiment achieves the following specific parameters:

[0172] Table 12 Specific parameters of zoom lens

[0173]

[0174] Furthermore, Fig.23 The vertical axis chromatic aberration curve of the zoom lens provided in the third embodiment of the present invention at the wide-angle end is as follows: Fig.23 As shown. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertex in the vertical axis represents the maximum pupil radius; the main wavelength uses 546.074nm, and the horizontal direction represents the offset relative to the main wavelength in micrometers (um). Fig.23 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within a small range, indicating that the vertical chromatic aberration of the zoom lens at the wide-angle end is well controlled and can meet the application requirements under normal conditions.

[0175] Fig.24 This is a light fan diagram of the zoom lens at the wide-angle end provided by the third embodiment of the present invention, such as Fig.24 As shown. In a single figure, the horizontal axis is the normalized beam aperture, and the vertical axis is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis, and all light rays in the field of view are focused on the same point on the image plane; the vertical axis in a single image can also be expressed as the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. Fig.24 It can be seen that in this zoom lens, each wavelength is well close to the horizontal axis in each field of view, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, the curves of each color are not obviously scattered, indicating that this zoom lens also has good correction for chromatic aberration, meeting the use requirements of this zoom lens.

[0176] Fig.25 The modulation transfer function curve of the zoom lens provided in the third embodiment of the present invention at the wide-angle end in the visible light band is as follows: Fig.25 The vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 435.8nm to 656.3nm, and the main wavelength is 546.074nm. Fig.25 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. When the value is 125 line pairs / mm, the transfer function is basically above 0.45, indicating that the image quality of the zoom lens at the wide-angle end is well controlled and meets the use requirements of 4k cameras.

[0177] Fig.26The modulation transfer function curve of the zoom lens provided in the third embodiment of the present invention at the wide-angle end in the near-infrared band is as follows: Fig.26 The vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated infrared band range is 830nm~870nm, and the main wavelength is 850nm. Fig.26 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. When the value is 125 line pairs / mm, the transfer function is basically above 0.3, indicating that the image quality of the zoom lens at the wide-angle end is well controlled and meets the use requirements of 4k cameras.

[0178] Fig. 27 The vertical axis chromatic aberration curve of the zoom lens provided in the third embodiment of the present invention at the telephoto end is as follows: Fig. 27 As shown. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertex in the vertical axis represents the maximum pupil radius; the main wavelength uses 546.074nm, and the horizontal direction represents the offset relative to the main wavelength in micrometers (um). Fig. 27 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within a small range, indicating that the vertical chromatic aberration of the zoom lens at the telephoto end is well controlled and can meet the application requirements under normal conditions.

[0179] Fig.28 This is a light fan diagram of the zoom lens at the telephoto end provided by the third embodiment of the present invention, such as Fig.28 As shown. In a single figure, the horizontal axis is the normalized beam aperture, and the vertical axis is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis, and all light rays in the field of view are focused on the same point on the image plane; the vertical axis in a single image can also be expressed as the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. Fig.28 It can be seen that the zoom lens is close to the horizontal axis at each wavelength in each field of view, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, the curves of each color are not obviously scattered, indicating that the zoom lens also has good correction for chromatic aberration, meeting the use requirements of the zoom lens.

[0180] Fig.29 The modulation transfer function curve of the zoom lens provided in the third embodiment of the present invention at the telephoto end in the visible light band is as follows: Fig.29 The vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated visible light band ranges from 435.8nm to 656.3nm, and the main wavelength is 546.074nm. Fig.29It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range. When the value is 125 line pairs / mm, the transfer function is basically above 0.3, indicating that the image quality of the zoom lens at the telephoto end is well controlled and meets the use requirements of 4k cameras.

[0181] Fig.30 The modulation transfer function curve of the zoom lens provided in the third embodiment of the present invention at the telephoto end in the near-infrared band is as follows: Fig.30 The vertical axis represents the modulation transfer function value, unit: none; the horizontal axis represents the spatial frequency, unit: cyc / mm. The simulated infrared band range is 830nm~870nm, and the main wavelength is 850nm. Fig.30 It can be seen that the modulation transfer function values ​​of each frequency under different fields of view are all controlled within a reasonable range, among which the transfer function at 125 line pairs / mm is basically above 0.3, and the MTF of each field of view is close to the diffraction limit. This shows that the image quality of this zoom lens at the telephoto end is well controlled and meets the use requirements of 4k cameras.

[0182] In order to explain the above embodiments more clearly, Table 13 details the specific optical and physical parameters of each lens in the zoom lens provided in Embodiments 1 to 3 of the present invention and other feasible optical and physical parameters.

[0183] Table 13 Design values ​​of optical physical parameters of zoom lens

[0184] Scope of protection Example 1 Example 2 Example 3 Lower limit Upper limit FT / FW≥5 5.18 5.01 5.01 5.01 F1 / FW -2.759 -2.662 -2.906 -2.906 -2.662 F2 / FW 2.272 2.440 2.576 2.272 2.576 F3 / FW 7.581 4.400 4.048 4.048 7.581 S1 / S2 1.136 0.888 0.999 0.888 1.136 nd1 1.59 1.57 1.55 1.55 1.59 nd3 1.74 1.69 1.68 1.68 1.74 nd5 1.54 1.63 1.63 1.54 1.63 nd6 1.50 1.61 1.61 1.50 1.61 nd10 1.66 1.54 1.63 1.54 1.66 vd1 68.62 56.13 75.50 56.13 75.50 vd3 52.68 54.57 55.52 52.68 55.52 vd5 55.99 24.64 24.64 24.64 55.99 vd6 81.61 57.97 57.97 57.97 81.61 vd10 20.38 53.81 23.18 20.38 53.81 F78 / F2 -5.537 -3.214 -2.379 -5.537 -2.379 F34 / F1 10.184 -70.754 57.563 -70.754 57.563 TTL / S2 2.986 2.700 2.808 2.700 2.986

[0185] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A zoom lens, characterized in that: It comprises a focus lens group, a zoom lens group and a fixed lens group which are arranged in sequence from the object plane to the image plane along the optical axis; the fixed lens group is fixedly arranged, and the focus lens group and the zoom lens group are movable along the optical axis direction; The focusing lens group has a negative optical power, the variable power lens group has a positive optical power, and the fixed lens group has a positive optical power; The focusing lens group includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence from the object plane to the image plane along the optical axis; The variable power lens group includes a sixth lens, a seventh lens, an eighth lens, a ninth lens and a tenth lens arranged in sequence from the object plane to the image plane along the optical axis; The fixed lens group includes an eleventh lens; The first lens has negative optical power, the second lens has negative optical power or positive optical power, the third lens has negative optical power; the fourth lens has positive optical power; the fifth lens has negative optical power, the sixth lens has positive optical power, the seventh lens has negative optical power, the eighth lens has positive optical power, the ninth lens has negative optical power or positive optical power, the tenth lens has negative optical power and the eleventh lens has positive optical power.

2. The zoom lens according to claim 1, wherein: The first lens is a convexoconcave lens, the second lens is a convexoconcave lens, the fourth lens is a biconcave lens, the sixth lens is a biconvex lens, the seventh lens is a convexoconcave lens, the eighth lens is a biconvex lens, the ninth lens is a convexoconcave lens, the tenth lens is a convexoconcave lens, and the eleventh lens is a convexoconvex lens.

3. The zoom lens according to claim 1, wherein: The second lens, the fifth lens, the sixth lens, the ninth lens, the tenth lens and the eleventh lens are all aspherical lenses; the first lens, the third lens, the fourth lens, the seventh lens and the eighth lens are all glass spherical lenses.

4. The zoom lens according to claim 1, wherein: The refractive index of the first lens is nd1, and the Abbe number is vd1; the refractive index of the third lens is nd3, and the Abbe number is vd3; the refractive index of the fifth lens is nd5, and the Abbe number is vd5; the refractive index of the sixth lens is nd6, and the Abbe number is vd6; the refractive index of the tenth lens is nd10, and the Abbe number is vd10, wherein: 1.55≤nd1≤1.59;56.13≤vd1≤75.50; 1.68≤nd3≤1.74;52.68≤vd3≤55.52; 1.54≤nd5≤1.63; 24.64≤vd5≤55.99; 1.50≤nd6≤1.61;57.97≤vd6≤81.61; 1.54≤nd10≤1.66;20.38≤vd10≤53.

81.

5. The zoom lens according to claim 1, wherein: The focal length of the focusing lens group is F1, the focal length of the variable magnification lens group is F2, the focal length of the fixed lens group is F3, and the focal length of the zoom lens at the wide-angle end is FW, wherein: -2.906≤F1 / FW≤-2.662; 2.272≤F2 / FW≤2.576; 4.048≤F3 / FW≤7.

581.

6. The zoom lens according to claim 1, wherein: The focal length of the zoom lens at the wide-angle end is FW, and the focal length of the zoom lens at the telephoto end is FT, wherein: FT / FW≥5.

7. The zoom lens according to claim 1, wherein: The maximum distance that the focus lens group can move is S1, and the maximum distance that the zoom lens group can move is S2, wherein: 0.888≤S1 / S2≤1.

136.

8. The zoom lens according to claim 1, wherein: The third lens and the fourth lens are glued together to form a first glued lens group, the focal length of the first glued lens group is F34, the seventh lens and the eighth lens are glued together to form a second glued lens group, the focal length of the second glued lens group is F78, the focal length of the focusing lens group is F1, and the focal length of the variable magnification lens group is F2, wherein: -70.754≤F34 / F1≤57.563;-5.537≤F78 / F2≤-2.

379.

9. The zoom lens according to claim 1, wherein: The total optical length of the zoom lens is TTL, and the maximum movable distance of the zoom lens group is S2, wherein: 2.700≤TTL / S2≤2.

986.

10. The zoom lens according to claim 1, wherein: The zoom lens further includes an aperture; The aperture stop is located in the optical path between the sixth lens and the seventh lens; or, the aperture stop is located in the optical path between the eighth lens and the ninth lens.

Images