A zoom lens

Abstract

The present invention discloses a zoom lens, comprising a focusing lens group, a variator lens group, and a fixed lens group arranged in sequence along an optical axis from an object plane to an image plane; the focusing lens group has a negative optical power, the variator lens group has a positive optical power, and the fixed lens group has a positive optical power; the first lens has a negative optical power, the second lens has a negative optical power or a positive optical power, and the third lens has a negative optical power; the fourth lens has a positive optical power; the fifth lens has a negative optical power, the sixth lens has a positive optical power, the seventh lens has a negative optical power, the eighth lens has a positive optical power, the ninth lens has a negative optical power or a positive optical power, the tenth lens has a negative optical power, and the eleventh lens has a positive optical power. This allows the zoom lens to meet imaging requirements across the entire wavelength range and has the advantages of small size and low distortion, thus meeting the requirements of security applications.

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, zoom lenses have gained widespread application in the security field due to their advantages such as long shooting distance and wide shooting angles. With the development of technology, cameras are gradually moving towards miniaturization and sophistication, which has also placed more stringent requirements on mainstream zoom lenses. Currently, 1 / 1.8" chips are gradually becoming the mainstream chip on the market and have a wider range of applications. However, traditional zoom lenses generally use 1 / 2.7" chips, which are difficult to use in a wide range of environments. Traditional zoom lenses also 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 compatible with the 1 / 1.8" chip. Summary of the Invention

[0003] The present 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, a zoom lens is provided, comprising a focus lens group, a variator lens group, and a fixed lens group arranged in sequence along an optical axis from an object plane to an image plane; the fixed lens group is fixed, and the focus lens group and the variator lens group are movable along the optical axis.

[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 zoom 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 convex-concave lens, the second lens is a convex-concave lens, the fourth lens is a biconcave lens, the sixth lens is a biconvex lens, the seventh lens is a convex-concave lens, the eighth lens is a biconvex lens, the ninth lens is a convex-concave lens, the tenth lens is a convex-concave lens, and the eleventh lens is a convex-concave 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 zoom lens group is S2, wherein:

[0025] 0.888≤S1 / S2≤1.136.

[0026] Optionally, the third lens and the fourth lens are cemented together to form a first cemented lens group, and the focal length of the first cemented lens group is F34; the seventh lens and the eighth lens are cemented together to form a second cemented lens group, and 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 variator 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 is located in the optical path between the sixth lens and the seventh lens; or, the aperture is located in the optical path between the eighth lens and the ninth lens.

[0032] The technical solution of the embodiments of the present invention provides a three-element zoom lens, comprising a focus lens group, a variable magnification lens group, and a fixed lens group, arranged sequentially along the optical axis from the object plane to the image plane. Specifically, the lens comprises 11 lenses, a relatively small number of which helps to reduce the lens length. By rationally matching the focus lens group, the variable magnification lens group, the fixed lens group, and the optical power of each lens, aberrations can be effectively corrected to ensure imaging quality. Furthermore, the zoom lens has the advantages of small size and low distortion, meeting the requirements of security applications.

[0033] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily 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 This is a schematic structural diagram of a zoom lens at the wide-angle end provided by the first embodiment of the present invention;

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

[0037] 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;

[0038] Figure 4 This is a ray fan diagram of the zoom lens provided in the first embodiment of the present invention at the wide-angle end;

[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 The 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 ray fan diagram of the zoom lens at the telephoto end provided by the first embodiment of the present invention;

[0043] Figure 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] Figure 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] Figure 11 A schematic structural diagram of the zoom lens at the wide-angle end provided in the second embodiment of the present invention;

[0046] Figure 12 A schematic structural diagram of a zoom lens at the telephoto end provided by the second embodiment of the present invention;

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

[0048] Figure 14 This is a ray fan diagram of the zoom lens provided in the second embodiment of the present invention at the wide-angle end;

[0049] Figure 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] Figure 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] Figure 17 The vertical axis chromatic aberration curve of the zoom lens provided in the second embodiment of the present invention at the telephoto end;

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

[0053] Figure 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] Figure 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] Figure 21 A schematic structural diagram of the zoom lens at the wide-angle end provided in the third embodiment of the present invention;

[0056] Figure 22 A schematic diagram of the structure of the zoom lens at the telephoto end provided by the third embodiment of the present invention;

[0057] Figure 23 This is a vertical chromatic aberration curve of the zoom lens provided in the third embodiment of the present invention at the wide-angle end;

[0058] Figure 24 This is a ray fan diagram of the zoom lens at the wide-angle end provided by the third embodiment of the present invention;

[0059] Figure 25 This is 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] Figure 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] Figure 27 The vertical axis chromatic aberration curve of the zoom lens provided in the third embodiment of the present invention at the telephoto end;

[0062] Figure 28 This is a ray fan diagram of the zoom lens at the telephoto end provided by the third embodiment of the present invention;

[0063] Figure 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] Figure 30 This is 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. DETAILED DESCRIPTION

[0065] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions 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 embodiments described 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 making creative efforts should fall within the scope of protection of the present invention.

[0066] It should be noted that the terms "first", "second", etc. in the description 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 numbers 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 thereof 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] Example 1

[0068] Figure 1 This is a structural diagram of a zoom lens at the wide-angle end provided in the first embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of the zoom lens at the telephoto end provided by the first embodiment of the present invention. Figure 1 and 2As shown, the zoom lens includes a focus lens group 10, a magnification lens group 11 and a fixed lens group 12 arranged in sequence along the optical axis from the object plane to the image plane; the fixed lens group 12 is fixed, and the focus lens group 10 and the magnification lens group 11 are movable along the optical axis; the focus lens group 10 has a negative focal power, the magnification lens group 11 has a positive focal power, and the fixed lens group 12 has a positive focal power; the focus lens group 10 includes a first lens 101, a second lens 102, a third lens 103, a fourth lens 104 and a fifth lens 105 arranged in sequence along the optical axis from the object plane to the image plane; the magnification lens group 11 includes a sixth lens arranged in sequence along the optical axis from the object plane to the image plane 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 negative optical power, the second lens 102 has negative optical power or positive optical power, the third lens 103 has negative optical power; the fourth lens 104 has positive optical power; the fifth lens 105 has negative optical power, the sixth lens 106 has positive optical power, the seventh lens 107 has negative optical power, the eighth lens 108 has positive optical power, the ninth lens 109 has negative optical power or positive optical power, the tenth lens 110 has negative optical power and the eleventh lens 111 has positive optical 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 position within the lens barrel, while the focus lens group 10 and the variator lens group 11 can reciprocate along the optical axis within the lens barrel. Through the combined movement of the focus lens group 10 and the variator lens group 11, the focal length of the zoom lens can be continuously changed from wide angle to telephoto, ensuring high image quality at all focal positions while also miniaturizing the zoom lens.

[0070] It can be understood that in the process of zooming achieved 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 optical power is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam, and it characterizes the ability of an optical system to deflect light. The larger the absolute value of the optical power, the stronger the ability to bend light, and the smaller the absolute value of the optical power, the weaker the ability to bend light. When the optical power is a positive number, the refraction of light is convergent; when the optical power is a negative number, the refraction of light is divergent. The optical power 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 zoom 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 zoom lens group 11 and the fixed lens group 12 cooperate with each other, which can compensate for the aberrations caused by the zoom movement of the focusing lens group 10 and the zoom lens group 11, and ensure 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 optical power, a second lens 102 with negative or positive optical power, a third lens 103 with negative optical power, a fourth lens 104 with positive optical power, and a fifth lens 105 with negative optical power, arranged in sequence along the optical axis from the object plane to the image plane. The zoom lens group 11 includes a sixth lens 106 with positive optical power, a seventh lens 107 with negative optical power, an eighth lens 108 with positive optical power, a ninth lens 109 with negative or positive optical power, and a tenth lens 110 with negative optical power, arranged in sequence along the optical axis from the object plane to the image plane. The fixed lens group 12 includes an eleventh lens 111 with positive optical power. The use of the focusing lens group 10 with negative optical power and the sixth lens 106 with positive optical power at the front end of the aperture ensures that light passing through the lens group 10 produces a larger light aperture, increasing the aperture number of the optical system and meeting the requirements of different conditions. By rationally allocating the optical power of each lens, it is beneficial to better correct aberrations and ensure image clarity at different focal lengths.

[0074] The zoom lens provided by the present invention utilizes only 11 lenses, a relatively small number of which helps reduce lens length. Furthermore, by properly combining the focal lengths of these 11 lenses, aberrations can be effectively corrected, resulting in a zoom lens that is confocal across the entire focal range. This lens is compatible with sensors as large as 1 / 1.8" and thus meets a wide range of security surveillance needs.

[0075] Furthermore, the third and fourth lenses 103 and 104 of the zoom lens form a doublet, while the seventh and eighth lenses 107 and 108 form a doublet. This reduces the air gap between the third and fourth lenses 103 and 104, as well as the air gap between the seventh and eighth lenses 107 and 108, further reducing the overall length of the lens. Furthermore, the doublet can be used to minimize or eliminate chromatic aberration, allowing for full correction of various aberrations in the zoom lens. This improves resolution and optimizes optical properties such as distortion and CRA while maintaining a compact structure. It also reduces light loss caused by inter-lens reflections, increasing illumination, thereby improving image quality and enhancing the clarity of the lens. Furthermore, the use of doublets reduces the number of components between the two lenses, simplifying the assembly process during lens manufacturing, reducing costs, and reducing the sensitivity to tolerances such as tilt and deflection that can occur during the lens unit 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 is generated when the light enters the structure behind the aperture, and improve the imaging quality of the optical system.

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

[0078] Furthermore, a flat glass 112 is provided along the object plane to the image plane; the flat glass 112 is located on the image side of the eleventh lens 111, and the flat 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, embodiments of the present invention provide a three-element zoom lens, comprising a focus lens group, a variable magnification lens group, and a fixed lens group, arranged sequentially along the optical axis from the object plane to the image plane. Specifically, 11 lenses are employed, resulting in a relatively small number of lenses, thereby reducing lens length. By rationally combining the focus lens group, the variable magnification lens group, and the fixed lens group, as well as the focal lengths of each lens, aberrations can be effectively corrected, ensuring image clarity at different focal lengths. Furthermore, the zoom lens offers the advantages of a small size, an ultra-wide angle, and a large aperture, meeting security surveillance requirements.

[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 properly setting the surface shape of each lens, the optical power of each lens is ensured to meet the optical power requirements of the above embodiment, while also ensuring that the entire zoom lens structure is compact and highly integrated.

[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 that can correct off-axis aberrations, including field curvature, coma, and astigmatism. 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 be made of glass aspherical lenses to better correct chromatic aberration and aberration, thereby improving image quality. In addition, the eleventh lens 111 in the fixed lens group 12 is an aspherical lens. Before the light reaches the image plane, the use of aspherical lenses can effectively correct aberrations and reduce CRA (chief ray angle), effectively improving image quality, and can be compatible with 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 plastic lenses is much lower than that of glass lenses, the cost of the zoom lens can be reduced. At the same time, glass and plastic can complement each other, balancing high and low temperatures and reducing the overall length of the lens. This allows the zoom lens to have stable high and low temperature performance, improves the environmental adaptability of the zoom lens, and can meet operating conditions of -40°C to 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 first lens 101 has a refractive index of nd1 and an Abbe number of vd1; the third lens 103 has a refractive index of nd3 and an Abbe number of vd3; the fifth lens 105 has a refractive index of nd5 and an Abbe number of vd5; the sixth lens 106 has a refractive index of nd6 and an Abbe number of vd6; and the tenth lens 110 has a refractive index of nd10 and an Abbe number of 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 primarily describes a material's ability to refract light, and different materials have different refractive indices. The Abbe number is an index used to indicate the dispersion capacity of a transparent medium. The greater the dispersion of the medium, the smaller the Abbe number; conversely, the less dispersion there is, the larger the Abbe number.

[0087] In order to ensure that the zoom optical system can form stable images at all focal lengths, it is usually necessary to separately eliminate chromatic aberrations and control aberrations of the fixed lens group 12 to prevent chromatic aberrations and aberrations from accumulating too much and being difficult to control after entering the moving lens group, thereby affecting image quality. The first lens 101 and the third lens 103 use the above-mentioned lens materials to control the chromatic aberrations and aberrations 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, resulting in difficulty in correction later. The fifth lens 105 and the sixth lens 106 use the above-mentioned lens materials to correct the chromatic aberrations and aberrations generated by the entire lens, and control them within a reasonable range before the light enters the image plane. In addition, aspheric lenses have a good ability to control high-order aberrations of the optical system. The use of aspheric lenses in the fifth lens 105, the sixth lens 106 and the tenth lens 110 can further reduce the high-order aberrations when the light enters the image plane, so that the image quality can be further improved to meet the needs of 4K imaging.

[0088] Furthermore, glass lenses are insensitive to temperature. Lenses using all-glass lenses offer more consistent performance across different temperatures, offering stable performance at both high and low temperatures, improving the environmental adaptability of zoom optical systems. The introduction of glass aspherical lenses also significantly corrects chromatic aberration and higher-order aberrations, offering a wider range of structural options compared to plastic aspherical lenses, thus enhancing the market competitiveness of lenses. Furthermore, the materials used for glass spherical lenses can be various types of glass, known to those skilled in the art, and will not be further elaborated in the present embodiments.

[0089] Optionally, the focal length of the focusing lens group 10 is F1, the focal length of the variator lens group 11 is F2, and the focal length of the fixed lens group 12 is F3. The focal length of the zoom lens at the wide-angle end is FW, where: -2.906≤F1 / FW≤-2.662; 2.272≤F2 / FW≤2.576; and 4.048≤F3 / FW≤7.581. The focal powers of the focusing lens group 10, the variator lens group 11, and the fixed lens group 12 are arranged in a negative-positive-positive pattern to achieve a reasonable combination of focal powers. At the same time, the ratio of the focal lengths of the focusing lens group 10, the variator 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 light can be smoothly passed through the lens, and higher-order aberrations can be largely corrected, thereby improving image quality. This also ensures that the zoom lens has 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 position of the aperture diaphragm relative to the image plane remains consistent at different focal lengths, and the aperture diameter is the same at different focal lengths. By controlling the focal length ratio of the zoom lens at the wide-angle end and the telephoto end, distortion can be controlled within a reasonably small range while ensuring a large zoom range and a large target area, thus meeting the requirement for small distortion 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 movable 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 cemented together to form a first cemented lens group, with a focal length of F34. The seventh lens 107 and the eighth lens 108 are cemented together to form a second cemented lens group, with a focal length of F78. The focal length of the focus lens group 10 is F1, and the focal length of the zoom lens group 11 is F2, where: -70.754 ≤ F34 / F1 ≤ 57.563; -5.537 ≤ F78 / F2 ≤ -2.379. By using this focal length combination in the focus lens group 10 of the zoom lens, light can pass smoothly through the front end of the lens, and before the light enters the zoom lens group 11, chromatic aberration and aberration generated at the front end are reduced, further improving 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 assembly 11 is S2, where: 2.700≤TTL / S2≤2.986. The limitation of the zoom lens assembly 11 and the total lens length can compress the lens space, ensuring that the required imaging quality and zoom range are met while maintaining a 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, meeting the use requirements in more situations. By controlling the aperture position of the zoom lens to remain consistent relative to the image plane position at different focal lengths and the aperture diameter to be the same at different focal lengths, the aperture range can be structurally reduced, ensuring that the movable group of the lens has a longer travel distance, achieving a higher imaging magnification or reducing the volume, and meeting the use requirements under different conditions.

[0096] In summary, the zoom lens provided by the present invention, by rationally allocating optical focal length, meets imaging requirements across the entire wavelength range of 436nm-850nm using a 1 / 1.8" large-area photosensitive chip, thereby achieving a zoom lens with a large aperture and infrared high and low temperature confocality.

[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 degree of curvature of the lens surface, a positive value represents that the surface is curved toward the image side, and a negative value represents that the surface is curved toward the object side, INF represents that the radius of curvature is infinite, and PL represents that the surface is flat; 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 light deflection ability of the material between the current surface and the next surface, and a blank 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 light between the current surface and the next surface, and a blank space represents that the current position is air; STO represents the aperture.

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

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

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

[0105] The aspheric surface shape equation Z 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 high-order aspheric coefficients of the fourth, sixth, eighth, tenth, twelfth, and fourteenth order aspheric surfaces, a i r i The combination becomes the high-order terms corresponding to the aspheric surface.

[0108] For example, 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] Further, Figure 3 This is the vertical axis chromatic aberration curve of the zoom lens provided in the first embodiment of the present invention at the wide-angle end, as shown in FIG. Figure 3 As shown. The vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertical axis vertex represents the maximum pupil radius; the main wavelength is 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 this 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 ray fan diagram of the zoom lens provided in the first embodiment of the present invention at the wide-angle end, as shown in FIG. Figure 4 As shown. In a single figure, the horizontal axis is the normalized beam diameter, 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 diffusion 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 As can be seen, the curves for each wavelength in each field of view of this zoom lens are well aligned with the horizontal axis, indicating that vertical aberrations at each wavelength are well corrected. Furthermore, the curves for each color have no noticeable dispersion, indicating that this zoom lens also effectively corrects chromatic aberration, meeting the requirements of its use.

[0118] Figure 5 This is 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, as shown in FIG. Figure 5 As shown. 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 range is 435.8nm~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. At 125 line pairs / mm, the transfer function is basically above 0.3, indicating that the image quality of this zoom lens at the wide-angle end is well controlled and meets the requirements of 4K camera use.

[0119] Figure 6This is 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 near-infrared band, as shown in FIG. Figure 6 As shown. 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. Among them, the transfer function at 125 line pairs / mm is basically above 0.3, indicating that the image quality of this zoom lens at the wide-angle end is well controlled and meets the requirements of 4K camera use.

[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 normalized aperture, 0 represents the optical axis, and the vertical axis vertex represents the maximum pupil radius; the main wavelength is 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 at 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 application requirements under normal conditions.

[0121] Figure 8 This is a ray fan diagram of the zoom lens at the telephoto end provided by the first embodiment of the present invention, as shown in FIG. Figure 8 As shown. In a single figure, the horizontal axis is the normalized beam diameter, 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 diffusion 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 As can be seen, this zoom lens's curves for all wavelengths at all fields of view are very close to the horizontal axis, indicating that vertical aberrations at all wavelengths are well corrected. Furthermore, the curves for each color have no noticeable dispersion, indicating that this zoom lens also effectively corrects chromatic aberration, meeting the requirements of its use.

[0122] Figure 9 This is 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, as shown in FIG. Figure 9 As shown. 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 range is 435.8nm~656.3nm, and the main wavelength is 546.074nm. Figure 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. Among them, the transfer function at 125 line pairs / mm is basically above 0.4, indicating that the image quality of this zoom lens at the telephoto end is well controlled and meets the requirements of 4K camera use.

[0123] Figure 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 shown as follows: Figure 10 As shown. 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 10 It can be seen that the modulation transfer function values ​​for each frequency at different fields of view are all within reasonable ranges. At 125 line pairs / mm, the transfer function is generally above 0.3, and the MTF across all fields of view approaches the diffraction limit. This demonstrates that this zoom lens has excellent image quality control at the telephoto end, meeting the requirements of 4K cameras.

[0124] Example 2

[0125] Figure 11 This is a schematic structural diagram of the zoom lens at the wide-angle end provided by the second embodiment of the present invention. Figure 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. Figure 11 and Figure 12As shown, the zoom lens includes a focus lens group 10, a magnification lens group 11 and a fixed lens group 12 arranged in sequence along the optical axis from the object plane to the image plane; the fixed lens group 12 is fixed, and the focus lens group 10 and the magnification lens group 11 are movable along the optical axis; the focus lens group 10 has a negative focal power, the magnification lens group 11 has a positive focal power, and the fixed lens group 12 has a positive focal power; the focus lens group 10 includes a first lens 201, a second lens 202, a third lens 203, a fourth lens 204 and a fifth lens 205 arranged in sequence along the optical axis from the object plane to the image plane; the magnification lens group 11 includes a sixth lens arranged in sequence along the optical axis from the object plane to the image plane The fixed lens group 12 includes the eleventh lens 211. The first lens 201 has negative focal power, the second lens 202 has negative or positive focal power, and the third lens 203 has negative focal power. The fourth lens 204 has positive focal power. The fifth lens 205 has negative focal power, the sixth lens 206 has positive focal power, the seventh lens 207 has negative focal power, the eighth lens 208 has positive focal power, the ninth lens 209 has negative or positive focal power, the tenth lens 210 has negative focal power, and the eleventh lens 211 has positive focal power. The aperture stop STO is located in the optical path between the eighth and ninth lenses 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 Figure 11 and Figure 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 degree of curvature of the lens surface, a positive value represents that the surface is curved toward the image side, and a negative value represents that the surface is curved toward the object side, INF represents that the radius of curvature is infinite, and PL represents that the surface is flat; 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 light deflection ability of the material between the current surface and the next surface, and a blank 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 light between the current surface and the next surface, and a blank 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] The aspheric 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 high-order aspheric coefficients of the fourth, sixth, eighth, tenth, twelfth, and fourteenth order aspheric surfaces, a i r i The combination becomes the high-order terms corresponding to the aspheric surface.

[0137] For example, 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 the zoom lens

[0139]

[0140]

[0141] Among them, -1.0842089226360E-05 means that the coefficient a4 of the 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] Further, Figure 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: Figure 13 As shown. The vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertical axis vertex represents the maximum pupil radius; the main wavelength is 546.074nm, and the horizontal direction represents the offset relative to the main wavelength, in micrometers (um). Figure 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 this zoom lens at the wide-angle end is well controlled and can meet the application requirements under normal conditions.

[0146] Figure 14 This is a ray fan diagram of the zoom lens provided in the second embodiment of the present invention at the wide-angle end, as shown in FIG. Figure 14 As shown. In a single figure, the horizontal axis is the normalized beam diameter, 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 diffusion 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 14 As can be seen, the curves for each wavelength in each field of view of this zoom lens are well aligned with the horizontal axis, indicating that vertical aberrations at each wavelength are well corrected. Furthermore, the curves for each color have no noticeable dispersion, indicating that this zoom lens also effectively corrects chromatic aberration, meeting the requirements of its use.

[0147] Figure 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: Figure 15 As shown. 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 range is 435.8nm~656.3nm, and the main wavelength is 546.074nm. Figure 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. Among them, the transfer function at 125 line pairs / mm is basically above 0.3, indicating that the image quality of this zoom lens at the wide-angle end is well controlled and meets the requirements of 4K camera use.

[0148] Figure 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 shown as follows: Figure 16 As shown. 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 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. Among them, the transfer function at 125 line pairs / mm is basically above 0.3, indicating that the image quality of this zoom lens at the wide-angle end is well controlled and meets the requirements of 4K camera use.

[0149] Figure 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: Figure 17 As shown. The vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertical axis vertex represents the maximum pupil radius; the main wavelength is 546.074nm, and the horizontal direction represents the offset relative to the main wavelength, in micrometers (um). Figure 17 It can be seen that the vertical chromatic aberration at 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 application requirements under normal conditions.

[0150] Figure 18 This is a ray fan diagram of the zoom lens at the telephoto end provided by the second embodiment of the present invention, as shown in FIG. Figure 18 As shown. In a single figure, the horizontal axis is the normalized beam diameter, 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 diffusion 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 18 As can be seen, this zoom lens's curves for all wavelengths at all fields of view are very close to the horizontal axis, indicating that vertical aberrations at all wavelengths are well corrected. Furthermore, the curves for each color have no noticeable dispersion, indicating that this zoom lens also effectively corrects chromatic aberration, meeting the requirements of its use.

[0151] Figure 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: Figure 19 As shown. 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 range is 435.8nm~656.3nm, and the main wavelength is 546.074nm. Figure 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. Among them, the transfer function at 125 line pairs / mm is basically above 0.4, indicating that the image quality of this zoom lens at the telephoto end is well controlled and meets the requirements of 4K camera use.

[0152] Figure 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: Figure 20 As shown. 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 20 It can be seen that the modulation transfer function values ​​for each frequency at different fields of view are all within reasonable ranges. At 125 line pairs / mm, the transfer function is generally above 0.25, and the MTF across all fields of view is close to the diffraction limit. This demonstrates that this zoom lens has excellent image quality control at the telephoto end, meeting the requirements of 4K cameras.

[0153] Example 3

[0154] Figure 21 This is a schematic diagram of the structure of the zoom lens at the wide-angle end provided by the third embodiment of the present invention. Figure 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. Figure 21 and Figure 22As shown, the zoom lens includes a focus lens group 10, a magnification lens group 11 and a fixed lens group 12 arranged in sequence from the object plane to the image plane along the optical axis; the fixed lens group 12 is fixed, and the focus lens group 10 and the magnification lens group 11 are movable along the optical axis; the focus lens group 10 has a negative focal power, the magnification lens group 11 has a positive focal power, and the fixed lens group 12 has a positive focal power; the focus lens group 10 includes a first lens 301, a second lens 2, a third lens 303, a fourth lens 304 and a fifth lens 305 arranged in sequence from the object plane to the image plane along the optical axis; the magnification lens group 11 includes a sixth lens arranged in sequence from the object plane to the image plane along the optical axis The fixed lens group 12 includes the eleventh lens 311. The first lens 301 has negative focal power, the second lens 302 has negative or positive focal power, and the third lens 303 has negative focal power. The fourth lens 304 has positive focal power. The fifth lens 305 has negative focal power, the sixth lens 306 has positive focal power, the seventh lens 307 has negative focal power, the eighth lens 308 has positive focal power, the ninth lens 309 has negative or positive focal power, the tenth lens 310 has negative focal power, and the eleventh lens 311 has positive focal power. The aperture 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 Figure 17 and Figure 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 degree of curvature of the lens surface, a positive value represents that the surface is curved toward the image side, and a negative value represents that the surface is curved toward the object side, INF represents that the radius of curvature is infinite, and PL represents that the surface is flat; 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 light deflection ability of the material between the current surface and the next surface, and a blank space represents that the current position is air, with a refractive index of 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 blank 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] The aspheric 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 high-order aspheric coefficients of the fourth, sixth, eighth, tenth, twelfth, and fourteenth order aspheric surfaces, a i r i The combination becomes the high-order terms corresponding to the aspheric surface.

[0166] For example, Table 11 describes in detail the aspheric coefficients of each lens in Example 3 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] Further, Figure 23 This is the vertical axis chromatic aberration curve of the zoom lens provided in the third embodiment of the present invention at the wide-angle end, as shown in FIG. Figure 23 As shown. The vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertical axis vertex represents the maximum pupil radius; the main wavelength is 546.074nm, and the horizontal direction represents the offset relative to the main wavelength, in micrometers (um). Figure 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 this zoom lens at the wide-angle end is well controlled and can meet the application requirements under normal conditions.

[0175] Figure 24 This is a ray fan diagram of the zoom lens provided in the third embodiment of the present invention at the wide-angle end, as shown in FIG. Figure 24 As shown. In a single figure, the horizontal axis is the normalized beam diameter, 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 diffusion 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 24 As can be seen, the curves for each wavelength in each field of view of this zoom lens are well aligned with the horizontal axis, indicating that vertical aberrations at each wavelength are well corrected. Furthermore, the curves for each color have no noticeable dispersion, indicating that this zoom lens also effectively corrects chromatic aberration, meeting the requirements of its use.

[0176] Figure 25 This is 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, as shown in FIG. Figure 25 As shown. 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 range is 435.8nm~656.3nm, and the main wavelength is 546.074nm. Figure 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. Among them, the transfer function at 125 line pairs / mm is basically above 0.45, indicating that the image quality of this zoom lens at the wide-angle end is well controlled and meets the requirements of 4K camera use.

[0177] Figure 26This is 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 near-infrared band, as shown in FIG. Figure 26 As shown. 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 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. Among them, the transfer function at 125 line pairs / mm is basically above 0.3, indicating that the image quality of this zoom lens at the wide-angle end is well controlled and meets the requirements of 4K camera use.

[0178] Figure 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: Figure 27 As shown. The vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertical axis vertex represents the maximum pupil radius; the main wavelength is 546.074nm, and the horizontal direction represents the offset relative to the main wavelength, in micrometers (um). Figure 27 It can be seen that the vertical chromatic aberration at 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 application requirements under normal conditions.

[0179] Figure 28 This is a ray fan diagram of the zoom lens at the telephoto end provided by the third embodiment of the present invention, as shown in FIG. Figure 28 As shown. In a single figure, the horizontal axis is the normalized beam diameter, 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 diffusion 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 28 As can be seen, this zoom lens's curves for all wavelengths at all fields of view are very close to the horizontal axis, indicating that vertical aberrations at all wavelengths are well corrected. Furthermore, the curves for each color have no noticeable dispersion, indicating that this zoom lens also effectively corrects chromatic aberration, meeting the requirements of its use.

[0180] Figure 29 This is 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, as shown in FIG. Figure 29 As shown. 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 range is 435.8nm~656.3nm, and the main wavelength is 546.074nm. Figure 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. Among them, the transfer function at 125 line pairs / mm is basically above 0.3, indicating that the image quality of this zoom lens at the telephoto end is well controlled and meets the requirements of 4K camera use.

[0181] Figure 30 This is 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, as shown in FIG. Figure 30 As shown. 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 30 It can be seen that the modulation transfer function values ​​for each frequency at different fields of view are all within reasonable ranges. At 125 line pairs / mm, the transfer function is generally above 0.3, and the MTF across all fields of view approaches the diffraction limit. This demonstrates that this zoom lens has excellent image quality control at the telephoto end, meeting the requirements of 4K cameras.

[0182] In order to more clearly illustrate the above embodiments, 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, as well as 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 embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A zoom lens, characterized in that: The zoom lens has three lens groups, including a focus lens group, a magnification-varying 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 fixed, and the focus lens group and the magnification-varying lens group are movable along the optical axis; 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 is composed of 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 zoom lens group is composed of 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; 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.

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

6. 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, where: 0.888≤S1 / S2≤1.

136.

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

379.

8. 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, where: 2.700≤TTL / S2≤2.

986.

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

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