zoom lens

Abstract

The present invention relates to a zoom lens, comprising: a first lens group having positive focal power, a second lens group having negative focal power, an aperture, a third lens group having positive focal power, a fourth lens group having positive focal power, and a fifth lens group having positive focal power, wherein the first lens group, the third lens group, and the fifth lens group are fixed lens groups, the second lens group is a zoom group, and the fourth lens group is a focusing group; when the second lens group moves along the optical axis, a zoom magnification change from a wide-angle end to a telephoto end is achieved; when the fourth lens group moves along the optical axis, a zoom magnification change from a wide-angle end to a telephoto end is achieved , achieving correction and focusing of image plane changes accompanying magnification change; the ratios of the focal length f1 of the first lens group, the focal length f2 of the second lens group, the focal length f3 of the third lens group, the focal length f4 of the fourth lens group, and the focal length f5 of the fifth lens group to the focal length fw of the zoom lens at the wide-angle end satisfy the following ranges: f1:fw=1.5~10, f2:fw=-3~-0.7, f3:fw=1~6, f4:fw=1.5~5.5, f5:fw=2~8.

Description

Technical Field

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

[0002] In the security surveillance industry, the pursuit of clarity is a key driver of its development. From standard definition to HD, full HD, and even ultra-high definition, video security surveillance has evolved from "visibility" to "clear vision" to "accurate vision" and finally to "AI recognition." The entire surveillance process relies on information acquisition through optical lenses, transmission of massive data streams, and back-end image processing.

[0003] With the commercialization of 5G technology and the rapid development of image processing technology, 4K surveillance is certain to become widespread in the near future. Zoom lenses with 4K resolution, due to their unique operating mode, can collect surveillance information several times higher than conventional fixed-focus lenses, and are poised to shine in the future security surveillance field. However, while currently offering 4K ultra-high resolution, zoom lenses often suffer from issues such as infrared non-convexity, small aperture values, poor 4K performance across the entire focal length range, and poor temperature adaptability. Summary of the Invention

[0004] The present invention aims to solve the above-mentioned problem and provide a zoom lens.

[0005] To achieve the above objectives, the present invention provides a zoom lens, comprising: a first lens group with positive focal power, a second lens group with negative focal power, an aperture stop, a third lens group with positive focal power, a fourth lens group with positive focal power, and a fifth lens group with positive focal power, arranged in sequence along the optical axis from the object side to the image side, wherein the first lens group, the third lens group, and the fifth lens group are fixed lens groups, the second lens group is a zoom group, and the fourth lens group is a focusing group.

[0006] When the second lens group moves along the optical axis, it realizes zooming from the wide-angle end to the telephoto end;

[0007] When the fourth lens group moves along the optical axis, correction and focusing of image plane changes accompanying magnification change are achieved;

[0008] The ratios of the focal length f1 of the first lens group, the focal length f2 of the second lens group, the focal length f3 of the third lens group, the focal length f4 of the fourth lens group, and the focal length f5 of the fifth lens group to the focal length fw at the wide-angle end of the zoom lens satisfy the following ranges, respectively:

[0009] f1:fw=1.5~10, f2:fw=-3~-0.7, f3:fw=1~6, f4:fw=1.5~5.5, f5:fw=2~8.

[0010] According to one aspect of the present invention, the first lens group includes a first lens having negative refractive power, a second lens having positive refractive power, and a third lens having positive refractive power;

[0011] The first lens is a convex-concave lens.

[0012] According to one aspect of the present invention, the second lens group includes a fourth lens having negative power, a fifth lens having negative power, a sixth lens having positive power, and a seventh lens having negative power;

[0013] The fifth lens is a biconcave lens.

[0014] According to one aspect of the present invention, the third lens group includes an eighth lens having positive power, a ninth lens having negative power, a tenth lens having positive power, an eleventh lens having negative power, a twelfth lens having positive power, and a thirteenth lens having negative power;

[0015] The eighth lens and the twelfth lens are biconvex lenses;

[0016] The thirteenth lens is a biconcave lens.

[0017] According to one aspect of the present invention, the fourth lens group includes a fourteenth lens having positive refractive power, a fifteenth lens having positive refractive power, and a sixteenth lens having negative refractive power;

[0018] The fourteenth lens and the fifteenth lens are biconvex lenses;

[0019] The sixteenth lens is a biconcave lens.

[0020] According to one aspect of the present invention, the fifth lens group includes a seventeenth lens having positive refractive power and an eighteenth lens having negative refractive power;

[0021] The seventeenth lens is a biconvex lens.

[0022] According to one aspect of the present invention, an optical length BFL of the eighteenth lens from the image plane of the zoom lens satisfies: 2<BFL<13.

[0023] According to one aspect of the present invention, the refractive index of the material of the seventh lens is in the range of 1.35 to 1.65.

[0024] According to one aspect of the present invention, the refractive index of the material of the eighth lens and the ninth lens is both in the range of 1.35 to 1.65.

[0025] According to one aspect of the present invention, the first lens and the second lens form a doublet lens.

[0026] According to one aspect of the present invention, the ninth lens, the tenth lens, and the eleventh lens form a triplet lens, and the twelfth lens and the thirteenth lens form a doublet lens.

[0027] According to one aspect of the present invention, the fifteenth lens and the sixteenth lens form a doublet lens.

[0028] According to one aspect of the present invention, the absolute value A of the difference in Abbe numbers between two adjacent lenses in each cemented lens satisfies: 15<A<80.

[0029] According to one aspect of the present invention, the second lens group, the third lens group, and the fourth lens group include at least one aspherical lens.

[0030] According to one aspect of the present invention, the distance D of the second lens group from the wide-angle end to the telephoto end of the zoom lens and the total length TTL of the zoom lens satisfy the following relationship: 0.15<D / TTL<0.536.

[0031] According to one aspect of the present invention, the diameter d of the largest lens in the first lens group and the total length TTL of the zoom lens satisfy the following relationship: 0.3<d / TTL<2.

[0032] The zoom lens of the present invention significantly reduces the tolerance sensitivity of optical components through reasonable lens group optical power matching, and can be mass-produced by meeting common process requirements.

[0033] The zoom lens of the present invention has a constant aperture, which can reach a maximum FNO 1.2, and has a black light-level night vision effect through matching image processing;

[0034] The zoom lens of the present invention corrects the position chromatic aberration and magnification chromatic aberration between 420 and 940 nm through the selection of specific materials, meeting 4K resolution and infrared confocality in the full focal length range. At the same time, the lens can achieve no out-of-focus in the full focal length range under an environment of -40°C to 80°C, greatly broadening the application scenarios of the lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a diagram schematically showing the structure of a zoom lens according to a first embodiment of the present invention;

[0036] Figure 2 This figure shows the MTF graph of the zoom lens according to the first embodiment of the present invention at the wide-angle end at room temperature of 20°C under visible light.

[0037] Figure 3This figure shows the MTF graph of the zoom lens according to the first embodiment of the present invention at room temperature of 20°C and at night with infrared wavelength of 850nm at long and wide angles.

[0038] Figure 4 This figure shows the MTF diagram of the zoom lens according to the first embodiment of the present invention at the telephoto end at room temperature of 20°C under visible light.

[0039] Figure 5 This figure shows the MTF graph of the zoom lens according to the first embodiment of the present invention at the telephoto end at room temperature of 20°C and at night with infrared light of 850nm.

[0040] Figure 6 This figure shows the MTF graph of the zoom lens according to the first embodiment of the present invention at the wide-angle end at a low temperature of -40 degrees Celsius and under visible light.

[0041] Figure 7 This figure shows the MTF graph of the zoom lens according to the first embodiment of the present invention at the wide-angle end at a high temperature of 80°C under visible light.

[0042] Figure 8 This figure shows the MTF graph of the zoom lens according to the first embodiment of the present invention at the telephoto end at a low temperature of -40 degrees Celsius and under visible light.

[0043] Figure 9 This figure shows the MTF graph of the zoom lens according to the first embodiment of the present invention at the telephoto end at a high temperature of 80 degrees Celsius under visible light.

[0044] Figure 10 is a diagram schematically showing the structure of a zoom lens according to a second embodiment of the present invention;

[0045] Figure 11 This figure shows the MTF graph of the zoom lens according to the second embodiment of the present invention at the wide-angle end at room temperature of 20°C under visible light.

[0046] Figure 12 This figure shows the MTF graph of the zoom lens according to the second embodiment of the present invention at room temperature of 20°C and at night with infrared wavelengths of 850nm at wide and long angles.

[0047] Figure 13 This figure shows the MTF graph of the zoom lens according to the second embodiment of the present invention at the telephoto end at room temperature of 20°C under visible light.

[0048] Figure 14 This figure shows the MTF graph of the zoom lens according to the second embodiment of the present invention at the telephoto end at room temperature of 20°C and at night with infrared light of 850nm.

[0049] Figure 15 This figure shows the MTF graph of the zoom lens according to the second embodiment of the present invention at the wide-angle end at a low temperature of -40 degrees Celsius and under visible light.

[0050] Figure 16This figure shows the MTF graph of the zoom lens according to the second embodiment of the present invention at the wide-angle end at a high temperature of 80°C under visible light.

[0051] Figure 17 This figure shows the MTF graph of the zoom lens according to the second embodiment of the present invention at the telephoto end at a low temperature of -40 degrees Celsius and under visible light.

[0052] Figure 18 This figure shows the MTF graph of the zoom lens according to the second embodiment of the present invention at the telephoto end at a high temperature of 80°C under visible light.

[0053] Figure 19 FIG2 is a diagram schematically showing the structure of a zoom lens according to a third embodiment of the present invention;

[0054] Figure 20 This figure shows the MTF graph of the zoom lens according to the third embodiment of the present invention at the wide-angle end at room temperature of 20°C under visible light.

[0055] Figure 21 This figure shows the MTF graph of the zoom lens according to the third embodiment of the present invention at room temperature of 20°C and at night with infrared light at 850nm and wide angle.

[0056] Figure 22 This figure shows the MTF graph of the zoom lens according to the third embodiment of the present invention at the telephoto end at room temperature of 20°C under visible light.

[0057] Figure 23 This figure shows the MTF graph of the zoom lens according to the third embodiment of the present invention at the telephoto end at room temperature of 20°C and at night with infrared light of 850nm.

[0058] Figure 24 This is an MTF graph of the zoom lens according to the third embodiment of the present invention at the wide-angle end at a low temperature of -40°C and under visible light.

[0059] Figure 25 This is an MTF graph of the zoom lens according to the third embodiment of the present invention at the wide-angle end at a high temperature of 80°C under visible light.

[0060] Figure 26 This figure shows the MTF graph of the zoom lens according to the third embodiment of the present invention at the telephoto end at a low temperature of -40 degrees Celsius and under visible light.

[0061] Figure 27 This figure shows the MTF graph of the zoom lens according to the third embodiment of the present invention at the telephoto end at a high temperature of 80°C under visible light. DETAILED DESCRIPTION

[0062] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0063] When describing the embodiments of the present invention, the orientation or positional relationship expressed by the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or positional relationship shown in the relevant drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0064] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments cannot be described one by one here, but the embodiments of the present invention are not limited to the following embodiments.

[0065] Figure 1 Schematically shows the structure of a zoom lens according to an embodiment of the present invention. Figure 1 As shown, the zoom lens of the present invention includes, arranged in order from the object side to the image side along the optical axis, a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, an aperture stop S, a third lens group G3 with positive refractive power, a fourth lens group G4 with positive refractive power, a fifth lens group G5 with positive refractive power, and a cover glass CG. In the present invention, the first lens group G1, the third lens group G3, and the fifth lens group G5 are fixed lens groups, the second lens group G2 is a zoom lens group, and the fourth lens group G4 is a focusing lens group.

[0066] In the present invention, the second lens group G2 moves along the optical axis to achieve zooming from the wide-angle end to the telephoto end, while the fourth lens group G4 moves along the optical axis to correct image plane fluctuations and adjust focus associated with zooming.

[0067] In the present invention, the ratios of the focal length f1 of the first lens group G1, the focal length f2 of the second lens group G2, the focal length f3 of the third lens group G3, the focal length f4 of the fourth lens group G4, and the focal length f5 of the fifth lens group G5 to the focal length fw of the zoom lens at the wide-angle end satisfy the following ranges, respectively:

[0068] f1:fw=1.5~10, f2:fw=-3~-0.7, f3:fw=1~6, f4:fw=1.5~5.5, f5:fw=2~8.

[0069] In the present invention, the first lens group G1 includes a first lens L1 having negative refractive power, a second lens L2 having positive refractive power, and a third lens L3 having positive refractive power. The first lens L1 is a convex-concave lens.

[0070] The second lens group G2 includes a fourth lens L4 with negative refractive power, a fifth lens L5 with negative refractive power, a sixth lens L6 with positive refractive power, and a seventh lens L7 with negative refractive power. The fifth lens L5 is a biconcave lens.

[0071] The third lens group G3 includes an eighth lens L8 with positive refractive power, a ninth lens L9 with negative refractive power, a tenth lens L10 with positive refractive power, an eleventh lens L11 with negative refractive power, a twelfth lens L12 with positive refractive power, and a thirteenth lens L13 with negative refractive power. The eighth lens L8 and the twelfth lens L12 are biconvex lenses, and the thirteenth lens L13 is biconcave.

[0072] The fourth lens group G4 includes a fourteenth lens L14 having positive refractive power, a fifteenth lens L15 having positive refractive power, and a sixteenth lens L16 having negative refractive power. The fourteenth lens L14 and the fifteenth lens L15 are biconvex lenses, and the sixteenth lens L16 is a biconcave lens.

[0073] The fifth lens group L5 includes a seventeenth lens L17 having positive refractive power and an eighteenth lens L18 having negative refractive power. The seventeenth lens L17 is a biconvex lens, and the optical length BFL of the eighteenth lens L18 from the image plane of the zoom lens satisfies 2<BFL<13.

[0074] In the present invention, the refractive index of the materials of the seventh lens L7, the eighth lens L8 and the ninth lens L9 are all within a range of 1.35 to 1.65.

[0075] Preferably, the first lens L1 and the second lens L2 form a doublet, the ninth lens L9, the tenth lens L10, and the eleventh lens L11 form a triplet, the twelfth lens L12 and the thirteenth lens L13 form a doublet, and the fifteenth lens L15 and the sixteenth lens L16 form a doublet. Furthermore, the absolute value A of the difference in Abbe number between two adjacent lenses in each of the above-mentioned cemented lenses satisfies the following: 15<A<80.

[0076] Furthermore, in the present invention, the second lens group G2, the third lens group G3, and the fourth lens group G4 include at least one aspheric lens, preferably a glass aspheric lens. The aspheric surface satisfies the following formula:

[0077]

[0078] Wherein, z is the axial distance from the surface to the vertex at a height h perpendicular to the optical axis along the optical axis; c represents the curvature at the vertex of the aspheric surface; k is the cone coefficient; A4, A6, A8, A10, and A12 represent the fourth-order, sixth-order, eighth-order, and twelfth-order aspheric coefficients, respectively.

[0079] The distance D of the second lens group G2 from the wide-angle end to the telephoto end of the zoom lens satisfies the following relationship with the total length TTL of the zoom lens: 0.15 < D / TTL < 0.536. The diameter d of the largest lens in the first lens group G1 satisfies the following relationship with the total length TTL of the zoom lens: 0.3 < d / TTL < 2.

[0080] The above configuration of the zoom lens according to the present invention significantly reduces the tolerance sensitivity of optical elements through reasonable lens group power matching, and can be mass-produced by meeting common processes.

[0081] The zoom lens of the present invention has a constant aperture, which can reach a maximum FNO 1.2, and has a black light-level night vision effect through matching image processing;

[0082] The zoom lens of the present invention corrects the position chromatic aberration and magnification chromatic aberration between 420 and 940 nm through the selection of specific materials, meeting 4K resolution and infrared confocality in the full focal length range. At the same time, the lens can achieve no out-of-focus in the full focal length range under an environment of -40°C to 80°C, greatly broadening the application scenarios of the lens.

[0083] The following describes three specific embodiments of the zoom lens according to the present invention, based on the above-described configuration. Because the zoom lens according to the present invention comprises a total of 18 lenses, in Embodiments 1 through 3, the first lens L1 and the second lens L2 form a doublet, the ninth lens L9, the tenth lens L10, and the eleventh lens L11 form a triplet, the twelfth lens L12 and the thirteenth lens L13 form a doublet, and the fifteenth lens L15 and the sixteenth lens L16 form a doublet. Together with the aperture stop S and the imaging surface IMA, the total number of surfaces is 35. For ease of description, the surfaces are numbered S1 through S35.

[0084] Implementation method one:

[0085] Figure 1 FIG. 1 is a diagram schematically showing the structure of a zoom lens according to a first embodiment of the present invention.

[0086] The aperture FNO in the first embodiment is 1.38.

[0087] Table 1 below lists the relevant parameters of each lens of this embodiment, including surface type, curvature radius, thickness, refractive index of the material, and Abbe number:

[0088]

[0089]

[0090] Table 1

[0091] In this embodiment, the aspheric surface data is shown in Table 2 below, where K is the quadratic surface constant of the surface, and A, B, C, D, and E are the aspheric coefficients of the fourth, sixth, eighth, tenth, and twelfth orders, respectively:

[0092] Surface number K A B C D E S15 0.354 -3.87E-06 3.34E-08 -9.75E-10 1.58E-11 -1.87E-13 S16 -1 1.20E-05 1.54E-08 -7.02E-10 1.18E-11 -1.73E-13

[0093] Table 2

[0094] In this embodiment, the zoom lens's wide-angle and telephoto magnification data are shown in Table 3 below:

[0095] Wide-angle end Telephoto end T1 1.1508 24.0511 T2 24.145 2.092 T3 8.20135 7.5503 T4 1.82 2.446

[0096] Table 3

[0097] In this embodiment, the ratios of the focal length f1 of the first lens group G1, the focal length f2 of the second lens group G2, the focal length f3 of the third lens group G3, the focal length f4 of the fourth lens group G4 and the focal length f5 of the fifth lens group G5 to the focal length fw at the wide-angle end of the zoom lens are: 3.83, -0.96, 2.937, 2.153 and 5.404, respectively.

[0098] The eighth lens L8 in the third lens group G3 is an aspherical lens;

[0099] The distance D of the second lens group G2 from the wide-angle end to the telephoto end of the zoom lens and the total length TTL of the zoom lens satisfy D / TTL=0.245;

[0100] The diameter d of the largest lens in the first lens group G1 and the total length TTL of the zoom lens satisfy the following relationship: d / TTL=0.425;

[0101] The refractive index of the seventh lens L7 is 1.52, the refractive index of the eighth lens L8 is 1.62, and the refractive index of the ninth lens L9 is 1.62.

[0102] The optical length BFL of the eighteenth lens L18 from the image plane is 6 mm.

[0103] Figures 2 to 9The figures respectively show the MTF graphs of the zoom lens according to the first embodiment of the present invention at the wide-angle end at a normal temperature of 20 degrees and visible light; the MTF graph at the wide-angle end at a normal temperature of 20 degrees and infrared light at night with a wavelength of 850 nm; the MTF graph at the telephoto end at a normal temperature of 20 degrees and visible light; the MTF graph at the telephoto end at a normal temperature of 20 degrees and infrared light at night with a wavelength of 850 nm; the MTF graph at the wide-angle end at a low temperature of -40 degrees and visible light; the MTF graph at the wide-angle end at a high temperature of 80 degrees and visible light; the MTF graph at the telephoto end at a low temperature of -40 degrees and visible light; and the MTF graph at the telephoto end at a high temperature of 80 degrees and visible light.

[0104] Depend on Figures 2 to 9 It can be seen that according to the setting of the zoom lens in this embodiment, the position chromatic aberration and magnification chromatic aberration between 420 and 940 nm are corrected, meeting the 4K resolution in the full focal length range and infrared confocality in the full focal length range. At the same time, the lens can achieve the characteristics of no defocus in the full focal length range under the environment of -40℃ to 80℃ and low sensitivity of optical components.

[0105] Implementation method 2:

[0106] Figure 10 FIG. 1 is a diagram schematically showing the structure of a zoom lens according to a second embodiment of the present invention.

[0107] In the second embodiment, the aperture FNO=1.2.

[0108] Table 4 below lists the relevant parameters of each lens of this embodiment, including surface type, radius of curvature, thickness, refractive index of the material, and Abbe number:

[0109]

[0110]

[0111] Table 4

[0112] In this embodiment, the aspheric surface data is shown in Table 5 below, where K is the quadratic constant of the surface, and A, B, C, D, and E are the aspheric coefficients of the fourth, sixth, eighth, tenth, and twelfth orders, respectively:

[0113] Surface number K A B C D E S12 1.000 -8.51E-06 7.35E-08 -2.15E-09 3.48E-11 -4.12E-13 S13 -1.00 2.65E-05 3.38E-08 -1.54E-09 2.59E-11 -3.80E-13 S15 0.389 -4.25E-06 3.67E-08 -1.07E-09 1.74E-11 -2.06E-13 S16 -1.15 1.32E-05 1.69E-08 -7.72E-10 1.29E-11 -1.90E-13

[0114] Table 5

[0115] In this embodiment, the zoom lens's wide-angle and telephoto magnification data are shown in Table 6 below:

[0116] Wide-angle end Telephoto end T1 2 17.5 T2 18 2.5 T3 8.20135 5.0453 T4 1.82 4.951

[0117] Table 6

[0118] In this embodiment, the ratios of the focal length f1 of the first lens group G1, the focal length f2 of the second lens group G2, the focal length f3 of the third lens group G3, the focal length f4 of the fourth lens group G4 and the focal length f5 of the fifth lens group G5 to the focal length fw at the wide-angle end of the zoom lens are: 3.74, -0.808, 3.415, 1.778 and 2.483, respectively.

[0119] The distance D of the second lens group G2 from the wide-angle end to the telephoto end of the zoom lens and the total length TTL of the zoom lens satisfy D / TTL=0.171;

[0120] The diameter d of the largest lens in the first lens group G1 and the total length TTL of the zoom lens satisfy the following relationship: d / TTL=0.383;

[0121] The refractive index of the seventh lens L7 is 1.53, the refractive index of the eighth lens L8 is 1.62, and the refractive index of the ninth lens L9 is 1.62.

[0122] The optical length BFL of the eighteenth lens L18 from the image plane is 10.3 mm.

[0123] Figures 11 to 18 1 and 2 represent the MTF graphs of the zoom lens according to the second embodiment of the present invention at the wide-angle end at a normal temperature of 20 degrees Celsius and under visible light; the MTF graph at the wide-angle end at a normal temperature of 20 degrees Celsius and under infrared light of 850 nm at night; the MTF graph at the telephoto end at a normal temperature of 20 degrees Celsius and under visible light; the MTF graph at the telephoto end at a normal temperature of 20 degrees Celsius and under infrared light of 850 nm at night; the MTF graph at the wide-angle end at a low temperature of -40 degrees Celsius and under visible light; the MTF graph at the wide-angle end at a high temperature of 80 degrees Celsius and under visible light; the MTF graph at the telephoto end at a low temperature of -40 degrees Celsius and under visible light; and the MTF graph at the telephoto end at a high temperature of 80 degrees Celsius and under visible light.

[0124] Depend on Figures 11 to 18 It can be seen that according to the setting of the zoom lens in this embodiment, the position chromatic aberration and magnification chromatic aberration between 420 and 940 nm are corrected, meeting the 4K resolution in the full focal length range and infrared confocality in the full focal length range. At the same time, the lens can achieve the characteristics of no defocus in the full focal length range under the environment of -40℃ to 80℃ and low sensitivity of optical components.

[0125] Implementation method three:

[0126] Figure 19 FIG. 1 is a diagram schematically showing the structure of a zoom lens according to a third embodiment of the present invention.

[0127] The aperture FNO in the second embodiment is 1.62.

[0128] Table 7 below lists the relevant parameters of each lens of this embodiment, including surface type, radius of curvature, thickness, refractive index of the material, and Abbe number:

[0129]

[0130]

[0131] Table 7

[0132] In this embodiment, the aspheric surface data is shown in Table 8 below, where K is the quadratic surface constant of the surface, and A, B, C, D, and E are the aspheric coefficients of the fourth, sixth, eighth, tenth, and twelfth orders, respectively:

[0133]

[0134]

[0135] Table 8

[0136] In this embodiment, the zoom lens's wide-angle and telephoto magnification data are shown in Table 9 below:

[0137] Wide-angle end Telephoto end T1 3.15 20.925 T2 19 1.225 T3 8 6.7993 T4 2.022 3.197

[0138] Table 9

[0139] In this embodiment, the ratios of the focal length f1 of the first lens group G1, the focal length f2 of the second lens group G2, the focal length f3 of the third lens group G3, the focal length f4 of the fourth lens group G4 and the focal length f5 of the fifth lens group G5 to the focal length fw at the wide-angle end of the zoom lens are: 2.11, -0.53, 3.133, 1.192 and 7.9, respectively.

[0140] The distance D of the second lens group G2 from the wide-angle end to the telephoto end of the zoom lens and the total length TTL of the zoom lens satisfy D / TTL=0.203;

[0141] The diameter d of the largest lens in the first lens group G1 and the total length TTL of the zoom lens satisfy the following relationship: d / TTL=0.335;

[0142] The refractive index of the seventh lens L7 is 1.53, the refractive index of the eighth lens L8 is 1.66, and the refractive index of the ninth lens L9 is 1.66.

[0143] The optical length BFL of the eighteenth lens L18 from the image plane is 5 mm.

[0144] Figures 20 to 271 and 2 represent the MTF graphs of the zoom lens according to the third embodiment of the present invention at the wide-angle end at a normal temperature of 20 degrees Celsius and under visible light; the MTF graph at the wide-angle end at a normal temperature of 20 degrees Celsius and under infrared light of 850 nm at night; the MTF graph at the telephoto end at a normal temperature of 20 degrees Celsius and under visible light; the MTF graph at the telephoto end at a normal temperature of 20 degrees Celsius and under infrared light of 850 nm at night; the MTF graph at the wide-angle end at a low temperature of -40 degrees Celsius and under visible light; the MTF graph at the wide-angle end at a high temperature of 80 degrees Celsius and under visible light; the MTF graph at the telephoto end at a low temperature of -40 degrees Celsius and under visible light; and the MTF graph at the telephoto end at a high temperature of 80 degrees Celsius and under visible light.

[0145] Depend on Figures 20 to 27 It can be seen that according to the setting of the zoom lens in this embodiment, the position chromatic aberration and magnification chromatic aberration between 420 and 940 nm are corrected, meeting the 4K resolution in the full focal length range and infrared confocality in the full focal length range. At the same time, the lens can achieve the characteristics of no defocus in the full focal length range under the environment of -40℃ to 80℃ and low sensitivity of optical components.

[0146] The above description is merely one embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A zoom lens comprising: Five lens groups are arranged in sequence along the optical axis from the object side to the image side: a first lens group (G1) with positive focal power, a second lens group (G2) with negative focal power, an aperture (S), a third lens group (G3) with positive focal power, a fourth lens group (G4) with positive focal power, and a fifth lens group (G5) with positive focal power, the first lens group (G1), the third lens group (G3), and the fifth lens group (G5) being fixed lens groups, the second lens group (G2) being a zoom group, and the fourth lens group (G4) being a focusing group; When the second lens group (G2) moves along the optical axis, zooming from the wide-angle end to the telephoto end is achieved; When the fourth lens group (G4) moves along the optical axis, correction and focusing of image plane changes accompanying magnification change are achieved; The invention is characterized in that the ratios of the focal length f1 of the first lens group (G1), the focal length f2 of the second lens group (G2), the focal length f3 of the third lens group (G3), the focal length f4 of the fourth lens group (G4) and the focal length f5 of the fifth lens group (G5) to the focal length fw of the zoom lens at the wide-angle end satisfy the following ranges in sequence: f1:fw=3.74~3.83, f2:fw=-0.96~-0.808, f3:fw=2.937~3.415, f4:fw=1.778~2.153, f5:fw=2~5.404; Or, when f3:fw=3.133, f1:fw=2.11, f2:fw=-0.53, f4:fw=1.192, f5:fw=7.9; The first lens group (G1) comprises a first lens (L1) with negative optical power, a second lens (L2) with positive optical power, and a third lens (L3) with positive optical power, a total of three lenses; The second lens group (G2) includes a fourth lens (L4) with negative optical power, a fifth lens (L5) with negative optical power, a sixth lens (L6) with positive optical power, and a seventh lens (L7) with negative optical power, a total of four lenses; The third lens group (G3) includes an eighth lens (L8) with positive focal power, a ninth lens (L9) with negative focal power, a tenth lens (L10) with positive focal power, an eleventh lens (L11) with negative focal power, a twelfth lens (L12) with positive focal power, and a thirteenth lens (L13) with negative focal power, for a total of six lenses; The fourth lens group (G4) includes a fourteenth lens (L14) with positive refractive power, a fifteenth lens (L15) with positive refractive power, and a sixteenth lens (L16) with negative refractive power, a total of three lenses; The fifth lens group (L5) includes a seventeenth lens (L17) with positive optical power and an eighteenth lens (L18) with negative optical power, a total of two lenses.

2. The zoom lens according to claim 1, wherein: The first lens (L1) is a convex-concave lens.

3. The zoom lens according to claim 1, wherein: The fifth lens (L5) is a biconcave lens.

4. The zoom lens according to claim 1, wherein: The eighth lens (L8) and the twelfth lens (L12) are biconvex lenses; The thirteenth lens (L13) is a biconcave lens.

5. The zoom lens according to claim 1, wherein: The fourteenth lens (L14) and the fifteenth lens (L15) are biconvex lenses; The sixteenth lens (L16) is a biconcave lens.

6. The zoom lens according to claim 1, wherein: The seventeenth lens (L17) is a biconvex lens.

7. The zoom lens according to claim 6, wherein: An optical length BFL between the eighteenth lens (L18) and the image plane of the zoom lens satisfies the following: 5 mm < BFL < 10.3 mm.

8. The zoom lens according to claim 3, wherein: The refractive index of the material of the seventh lens (L7) is in the range of 1.35 to 1.

65.

9. The zoom lens according to claim 4, wherein: The refractive index range of the materials of the eighth lens (L8) and the ninth lens (L9) is 1.35 to 1.

65.

10. The zoom lens according to claim 2, wherein: The first lens (L1) and the second lens (L2) form a doublet lens.

11. The zoom lens according to claim 4, wherein: The ninth lens (L9), the tenth lens (L10) and the eleventh lens (L11) form a triplet lens, and the twelfth lens (L12) and the thirteenth lens (L13) form a doublet lens.

12. The zoom lens according to claim 5, wherein: The fifteenth lens (L15) and the sixteenth lens (L16) form a doublet lens.

13. The zoom lens according to any one of claims 10 to 12, wherein: The absolute value A of the difference in Abbe numbers between two adjacent lenses in each cemented lens satisfies: 15<A<80.

14. The zoom lens according to any one of claims 1 to 12, wherein: The second lens group (G2), the third lens group (G3) and the fourth lens group (G4) include at least one aspherical lens.

15. The zoom lens according to any one of claims 1 to 12, wherein: The distance D of the second lens group (G2) from the wide-angle end to the telephoto end of the zoom lens and the total length TTL of the zoom lens satisfy the following relationship: 0.171 <D / TTL <0.

245.

16. The zoom lens according to any one of claims 1 to 12, wherein: The diameter d of the largest lens in the first lens group (G1) and the total length TTL of the zoom lens satisfy the following relationship: 0.335<d / TTL<0.425.

Images