Zoom lens

Abstract

The invention discloses a zoom lens, which belongs to the technical field of optical lenses and comprises a first lens group with positive focal power, a second lens group with negative focal power, a diaphragm, a third lens group with positive focal power and a fourth lens group with positive focal power which are sequentially arranged from an object plane to an image plane along an optical axis direction, wherein the first lens group and the third lens group are fixed groups, the second lens group is a zooming group so as to realize zooming from a wide-angle end to a long-focus end by moving from an object plane to an image plane along an optical axis direction, and the fourth lens group is a focusing group so as to move along the optical axis direction for zooming; and the ratio of the total optical length of the zoom lens to the axial distance from the mirror surface closest to the object surface when the second lens group is at the wide-angle end to the mirror surface closest to the image surface when the second lens group is at the long-focus end is reasonably set. The chromatic aberration, aberration, distortion, infrared performance and high and low temperature performance of the zoom lens can be effectively balanced, good imaging quality can be achieved under different focal lengths, and miniaturization of the zoom lens is facilitated.

Description

Technical Field

[0001] This invention belongs to the field of optical lens technology, and specifically relates to a zoom lens. Background Technology

[0002] In the security industry, zoom lenses are widely used due to their variable focal length. With the development of the security industry, the requirements for zoom lenses in terms of resolution, aperture, distortion, infrared performance, and high / low temperature performance are becoming increasingly stringent. High resolution allows for clearer resolution of image details, which is essential in security monitoring; a large aperture increases the overall brightness of the image, ensuring clear viewing even in low-light environments; a constant aperture ensures consistent brightness during zooming, meeting the brightness requirements of various scenarios; low distortion minimizes image distortion during use, capturing more image details; confocal infrared and visible light bands adapt to various monitoring environments, including daytime, dusk, and nighttime; and a well-designed high / low temperature compensation system ensures consistent resolution regardless of whether the lens needs refocusing in extremely hot or cold environments. However, currently available zoom lenses generally have low resolution, small aperture, and significant distortion, making them unsuitable for practical applications and limiting their applicability. Summary of the Invention

[0003] The purpose of this invention is to address the above-mentioned problems by proposing a zoom lens that can effectively balance chromatic aberration, aberration, distortion, infrared performance, and high and low temperature performance, achieving good image quality at different focal lengths, and is also more compact.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] The present invention proposes a zoom lens comprising, sequentially arranged along the optical axis from the object plane to the image plane, a first lens group with positive optical power, a second lens group with negative optical power, an aperture stop, a third lens group with positive optical power, and a fourth lens group with positive optical power, wherein:

[0006] The first and third lens groups are fixed groups, the second lens group is a zoom group to achieve zoom from wide-angle to telephoto by moving along the optical axis from the object plane to the image plane, and the fourth lens group is a focusing group to move along the optical axis for zoom.

[0007] Zoom lenses also meet the following conditions:

[0008] 2.5≤ ≤5;

[0009] in, The total optical length of the zoom lens is in mm. The distance on the axis is from the mirror closest to the object plane when the second lens group is at the wide-angle end to the mirror closest to the image plane when the second lens group is at the telephoto end, in mm.

[0010] Preferably, the first lens group includes a first lens with negative optical power, a second lens with positive optical power, and a third lens with positive optical power arranged sequentially from the object plane to the image plane along the optical axis, and the first lens and the second lens form a first cemented doublet lens group.

[0011] The second lens group includes a fourth lens with negative optical power, a fifth lens with negative optical power, and a sixth lens with positive optical power, arranged sequentially from the object plane to the image plane along the optical axis.

[0012] The third lens group includes a seventh lens with positive optical power, an eighth lens with negative optical power, a ninth lens with positive optical power, a tenth lens with negative optical power, an eleventh lens with positive optical power, and a twelfth lens with negative optical power, arranged sequentially from the object plane to the image plane along the optical axis. The eighth and ninth lenses form the second cemented doublet lens group, and the tenth, eleventh, and twelfth lenses form the first cemented triplet lens group.

[0013] The fourth lens group includes a thirteenth lens with positive optical power, a fourteenth lens with negative optical power, a fifteenth lens with positive optical power, and a sixteenth lens with negative optical power arranged sequentially from the object plane to the image plane along the optical axis, and the thirteenth lens and the fourteenth lens form the third cemented doublet lens group.

[0014] Preferably, the image-side mirror of the fourth lens is concave, the object-side mirror of the fifth lens is concave, the object-side mirror of the sixth lens is convex, the object-side mirror of the seventh lens is convex, the object-side mirror of the eighth lens is concave, the image-side mirror of the twelfth lens is convex, the object-side mirror of the thirteenth lens is convex, the image-side mirror of the fourteenth lens is concave, and the object-side mirror of the sixteenth lens is concave.

[0015] Preferably, the zoom lens also meets the following conditions:

[0016] 5.5≤ ≤9;

[0017] in, The diameter of the maximum imaging surface of the zoom lens, in mm.

[0018] Preferably, the zoom lens also meets the following conditions:

[0019] 4.5≤ ≤7;

[0020] in, The focal length of the zoom lens at its telephoto end, in mm; This is the focal length of the zoom lens at its wide-angle end, in mm.

[0021] Preferably, the zoom lens also meets the following conditions:

[0022] 1.5≤ ≤2.2;

[0023] in, The focal length of the zoom lens at its telephoto end, in mm; This is the focal length of the zoom lens at its wide-angle end, in mm.

[0024] Preferably, the zoom lens also meets the following conditions:

[0025] 2≤ ≤4.5;

[0026] in, The focal length of the third lens group is in mm. This is the focal length of the zoom lens at its wide-angle end, in mm.

[0027] Preferably, the zoom lens also meets the following conditions:

[0028] 0.4≤ ≤0.9;

[0029] in, The focal length of the second lens group is in mm. This refers to the focal length of the zoom lens at its telephoto end, in mm.

[0030] Preferably, the zoom lens also meets the following conditions:

[0031] 0.6≤ ≤1.5;

[0032] in, The focal length of the zoom lens at its telephoto end, in mm; The object-side aperture of the first lens in the first lens group closest to the object plane is half the diameter, in mm.

[0033] Preferably, the Abbe number of one lens in the first lens group is 50 to 95; the refractive index of the first lens closest to the object surface in the third lens group is 1.8 to 2.2, and the Abbe number of at least one lens in the third lens group is 60 to 95.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] 1) By rationally allocating the focal length, number of lenses and parameter relationships of each lens group, this zoom lens ensures a balanced quality across the entire focal length range, giving it superior performance such as high resolution, large aperture, and constant aperture, while also making it more compact.

[0036] 2) The reasonable allocation of low-dispersion glass and high-refractive-index glass achieves excellent confocal imaging capability for visible and infrared light. At the same time, it has a temperature compensation function, which solves the focus drift problem in high and low temperature environments. It does not have defocus in the temperature range of -40℃ to +80℃, and still has good resolution in the large aperture state, achieving a clear imaging effect. It has a wide range of applications.

[0037] 3) Reasonable allocation of focal length and shape of each lens group and lens within each lens group helps to reduce assembly tolerances between lens groups and between lenses within each lens group, which facilitates assembly and improves assembly yield.

[0038] 4) It can correct chromatic aberration and secondary spectrum in the 380nm~940nm band, and can ensure high resolution without refocusing when switching between day and night.

[0039] 5) It can focus on a wide range of object distances, and can ensure clear imaging from 0.1m to infinity across the entire focal length range. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the zoom lens at the wide-angle end of Embodiment 1 of the present invention;

[0041] Figure 2 This is a schematic diagram of the zoom lens at the telephoto end in Embodiment 1 of the present invention;

[0042] Figure 3 This is a magnification chromatic aberration diagram of the zoom lens at the wide-angle end in Embodiment 1 of the present invention;

[0043] Figure 4 This is a chromatic aberration diagram of the zoom lens at the wide-angle end in Embodiment 1 of the present invention;

[0044] Figure 5 This is a distortion image of the zoom lens at the wide-angle end in Embodiment 1 of the present invention;

[0045] Figure 6 This is a magnification chromatic aberration diagram of the zoom lens at the telephoto end in Embodiment 1 of the present invention.

[0046] Figure 7 This is a chromatic aberration diagram of the zoom lens at the telephoto end in Embodiment 1 of the present invention;

[0047] Figure 8 This is a distortion image of the zoom lens at the telephoto end in Embodiment 1 of the present invention;

[0048] Figure 9 This is a schematic diagram of the zoom lens at the wide-angle end in Embodiment 2 of the present invention;

[0049] Figure 10 This is a schematic diagram of the zoom lens at the telephoto end in Embodiment 2 of the present invention;

[0050] Figure 11 This is a magnification chromatic aberration diagram of the zoom lens at the wide-angle end in Embodiment 2 of the present invention;

[0051] Figure 12 This is a chromatic aberration diagram of the zoom lens at the wide-angle end in Embodiment 2 of the present invention;

[0052] Figure 13 This is a distortion image of the zoom lens at the wide-angle end in Embodiment 2 of the present invention;

[0053] Figure 14 This is a magnification chromatic aberration diagram of the zoom lens at the telephoto end in Embodiment 2 of the present invention;

[0054] Figure 15 This is a chromatic aberration diagram of the zoom lens at the telephoto end in Embodiment 2 of the present invention;

[0055] Figure 16 This is a distortion image of the zoom lens at the telephoto end in Embodiment 2 of the present invention;

[0056] Figure 17 This is a schematic diagram of the zoom lens at the wide-angle end of Embodiment 3 of the present invention;

[0057] Figure 18 This is a schematic diagram of the zoom lens at the telephoto end in Embodiment 3 of the present invention;

[0058] Figure 19 This is a magnification chromatic aberration diagram of the zoom lens at the wide-angle end in Embodiment 3 of the present invention;

[0059] Figure 20 This is a chromatic aberration diagram of the zoom lens at the wide-angle end in Embodiment 3 of the present invention;

[0060] Figure 21 This is a distortion image of the zoom lens at the wide-angle end in Embodiment 3 of the present invention;

[0061] Figure 22 This is a magnification chromatic aberration diagram of the zoom lens at the telephoto end in Embodiment 3 of the present invention;

[0062] Figure 23 This is a chromatic aberration diagram of the zoom lens at the telephoto end in Embodiment 3 of the present invention;

[0063] Figure 24 This is a distortion diagram of the zoom lens at the telephoto end in Embodiment 3 of the present invention.

[0064] Explanation of reference numerals in the attached diagram: G1, first lens group; G2, second lens group; Stop, aperture stop; G3, third lens group; G4, fourth lens group; Image, image plane; L1, first lens; L2, second lens; L3, third lens; L4, fourth lens; L5, fifth lens; L6, sixth lens; L7, seventh lens; L8, eighth lens; L9, ninth lens; L10, tenth lens; L11, eleventh lens; L12, twelfth lens; L13, thirteenth lens; L14, fourteenth lens; L15, fifteenth lens; L16, sixteenth lens. Detailed Implementation

[0065] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0066] It should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application.

[0067] like Figures 1-24 As shown, a zoom lens includes a first lens group with positive optical power, a second lens group with negative optical power, an aperture stop, a third lens group with positive optical power, and a fourth lens group with positive optical power, arranged sequentially from the object plane to the image plane along the optical axis, wherein:

[0068] The first and third lens groups are fixed groups, the second lens group is a zoom group to achieve zoom from wide-angle to telephoto by moving along the optical axis from the object plane to the image plane, and the fourth lens group is a focusing group to move along the optical axis for zoom.

[0069] Zoom lenses also meet the following conditions:

[0070] 2.5≤ ≤5;

[0071] in, The total optical length of the zoom lens is in mm. The distance on the axis is from the mirror closest to the object plane when the second lens group is at the wide-angle end to the mirror closest to the image plane when the second lens group is at the telephoto end, in mm.

[0072] The zoom lens consists of three groups: the first and third lens groups are fixed; the second lens group is a zoom group used for continuous zooming from wide-angle to telephoto by moving along the optical axis from the object plane to the image plane; and the fourth lens group is a focusing group used to compensate for changes in the image plane position during zooming by moving along the optical axis, thus maintaining image plane stability. This is achieved by appropriately setting the total optical length (TTL) of the zoom lens and the axial distance between the mirror closest to the object plane when the second lens group is at the wide-angle end and the mirror closest to the image plane when the second lens group is at the telephoto end. The ratio between these two values ​​can effectively ensure that the zoom lens has good resolution. If the above relationship is less than the lower limit, it is difficult to achieve high resolution of the zoom lens. If the above relationship is greater than the upper limit, it is not conducive to achieving a large field of view at the wide-angle end of the zoom lens, and the overall volume is large, which is not conducive to the miniaturization of the zoom lens.

[0073] In one embodiment, the first lens group includes a first lens with negative optical power, a second lens with positive optical power, and a third lens with positive optical power arranged sequentially from the object plane to the image plane along the optical axis, and the first lens and the second lens form a first cemented doublet lens group.

[0074] The second lens group includes a fourth lens with negative optical power, a fifth lens with negative optical power, and a sixth lens with positive optical power, arranged sequentially from the object plane to the image plane along the optical axis.

[0075] The third lens group includes a seventh lens with positive optical power, an eighth lens with negative optical power, a ninth lens with positive optical power, a tenth lens with negative optical power, an eleventh lens with positive optical power, and a twelfth lens with negative optical power, arranged sequentially from the object plane to the image plane along the optical axis. The eighth and ninth lenses form the second cemented doublet lens group, and the tenth, eleventh, and twelfth lenses form the first cemented triplet lens group.

[0076] The fourth lens group includes a thirteenth lens with positive optical power, a fourteenth lens with negative optical power, a fifteenth lens with positive optical power, and a sixteenth lens with negative optical power arranged sequentially from the object plane to the image plane along the optical axis, and the thirteenth lens and the fourteenth lens form the third cemented doublet lens group.

[0077] The zoom lens achieves a constant large aperture thanks to the first cemented doublet lens group, composed of the first and second lenses in the first lens group. The combination of lenses within this first group enables the zoom lens to achieve high resolution and infrared confocal performance at the telephoto end. By rationally configuring the optical power of the lenses in the second lens group, the zoom lens maintains uniform high resolution across the entire focal length during zooming and facilitates temperature compensation across the entire focal length. This allows the zoom lens to maintain high resolution even in high or low temperature environments, from wide-angle to telephoto. Furthermore, the rational configuration of the optical power of the lenses in the third lens group, the positions of the cemented doublet and triplet lenses, and the combination of these lenses effectively corrects chromatic aberration and spherical aberration, ensuring high resolution and facilitating large aperture performance. This also plays a crucial role in achieving visible and infrared confocal performance and is beneficial for lens assembly tolerances within the third lens group. By properly configuring the optical power of each lens in the fourth lens group, the field curvature and astigmatism of the zoom lens can be effectively corrected, achieving high resolution for the zoom lens and facilitating the achievement of the principal ray incident angle of the zoom lens.

[0078] In one embodiment, the image-side mirror of the fourth lens is concave, the object-side mirror of the fifth lens is concave, the object-side mirror of the sixth lens is convex, the object-side mirror of the seventh lens is convex, the object-side mirror of the eighth lens is concave, the image-side mirror of the twelfth lens is convex, the object-side mirror of the thirteenth lens is convex, the image-side mirror of the fourteenth lens is concave, and the object-side mirror of the sixteenth lens is concave.

[0079] Among them, the fourth, fifth, and sixth lenses belonging to the second lens group meet the above shape requirements, which is beneficial for achieving high resolution across the entire focal length of the lens. The seventh, eighth, and twelfth lenses belonging to the third lens group meet the above shape requirements and are reasonably matched with optical power, which is beneficial for improving the overall chromatic aberration and aberration levels of the zoom lens, and for achieving high resolution. The thirteenth, fourteenth, and sixteenth lenses belonging to the fourth lens group meet the above shape requirements, which is beneficial for correcting astigmatism in the zoom lens and reducing the angle of incidence of the principal ray, while also helping to avoid focused high-energy ghosting.

[0080] In one embodiment, the zoom lens also satisfies the following condition:

[0081] 5.5≤ ≤9;

[0082] in, The diameter of the maximum imaging surface of the zoom lens, in mm.

[0083] Using this relationship to constrain zoom lens parameters is beneficial for achieving a large zoom lens surface and minimizing its size. If the above relationship exceeds the upper limit, the zoom lens will be longer and larger, hindering miniaturization. If the above relationship is less than the lower limit, it will be difficult to achieve high resolution for the zoom lens.

[0084] In one embodiment, the zoom lens also satisfies the following condition:

[0085] 4.5≤ ≤7;

[0086] in, The focal length of the zoom lens at its telephoto end, in mm; This is the focal length of the zoom lens at its wide-angle end, in mm.

[0087] If the above relationship is less than the lower limit, it will be difficult to achieve high resolution for zoom lenses; if the above relationship is greater than the upper limit, it will be detrimental to the miniaturization of zoom lenses.

[0088] In one embodiment, the zoom lens also satisfies the following condition:

[0089] 1.5≤ ≤2.2;

[0090] in, The focal length of the zoom lens at its telephoto end, in mm; This is the focal length of the zoom lens at its wide-angle end, in mm.

[0091] If the above relationship exceeds the upper limit, it will hinder the achievement of a constant aperture in zoom lenses and result in a larger second lens group, increasing costs. If the above relationship is less than the lower limit, it will hinder the achievement of high resolution across the entire focal length range of zoom lenses.

[0092] In one embodiment, the zoom lens also satisfies the following condition:

[0093] 2≤ ≤4.5;

[0094] in, The focal length of the third lens group is in mm. This is the focal length of the zoom lens at its wide-angle end, in mm.

[0095] Using this formula to constrain the ratio of the focal length of the third lens group to the focal length of the zoom lens at the wide-angle end is beneficial to further improve the uniform high resolution of the zoom lens across the entire focal length range while ensuring large aperture performance.

[0096] In one embodiment, the zoom lens also satisfies the following condition:

[0097] 0.4≤ ≤0.9;

[0098] in, The focal length of the second lens group is in mm. This refers to the focal length of the zoom lens at its telephoto end, in mm.

[0099] Using this formula to constrain the ratio of the focal length of the second lens group to the focal length of the zoom lens at the telephoto end helps to balance the contradiction between the high resolution and size of the zoom lens, and also helps to achieve a large field of view at the wide-angle end of the zoom lens.

[0100] In one embodiment, the zoom lens also satisfies the following condition:

[0101] 0.6≤ ≤1.5;

[0102] in, The focal length of the zoom lens at its telephoto end, in mm; The object-side aperture of the first lens in the first lens group closest to the object plane is half the diameter, in mm.

[0103] Using this relationship to constrain the ratio of the focal length of the zoom lens at the telephoto end to the half-aperture of the object-side mirror surface of the first lens in the first lens group of the zoom lens, which is close to the object surface, is beneficial to achieving sufficient and uniform relative illumination performance across the entire focal length while ensuring that the zoom lens is relatively small in size.

[0104] In one embodiment, the first lens group has an Abbe number of 50 to 95; the first lens in the third lens group near the object surface has a refractive index of 1.8 to 2.2, and at least one lens in the third lens group has an Abbe number of 60 to 95.

[0105] The zoom lens incorporates a low-dispersion lens in its first element, ensuring both large aperture performance at the telephoto end and good chromatic aberration correction. The third element effectively balances the chromatic aberration of the first and second elements, achieving correction for chromatic aberration and secondary spectrum in the 380nm-940nm wavelength range. This ensures high-resolution imaging without refocusing during day / night transitions.

[0106] Specifically, the zoom lens includes a first lens group, a second lens group, an aperture stop, a third lens group, and a fourth lens group arranged sequentially along the optical axis from the object plane to the image plane. The first lens group has positive optical power and contains three lenses, the second lens group has negative optical power and contains three lenses, the third lens group has positive optical power and contains six lenses, and the fourth lens group has positive optical power and contains four lenses. It also includes a protective chip glass located on the image side of the fourth lens group. Continuous zoom from the wide-angle end to the telephoto end is achieved by moving the second lens group along the optical axis from the object plane to the image plane, and compensation for changes in the image plane position during zooming is achieved by moving the fourth lens group along the optical axis.

[0107] The material and shape of each lens can be adjusted according to actual needs, and the following embodiments are given to illustrate the changes in the material and related parameters of each lens in the zoom lens of this application.

[0108] Example 1:

[0109] The following is for reference Figures 1-8 This embodiment describes the zoom lens. Figure 1 This is a schematic diagram of the zoom lens at the wide-angle end in this embodiment. Figure 2 This is a schematic diagram of the zoom lens at the telephoto end in this embodiment. Figures 3-5 The images shown in sequence are chromatic aberration at magnification, positional chromatic aberration, and distortion at the wide-angle end of the zoom lens in this embodiment. Figures 6-8 The images shown are, in order, the chromatic aberration at magnification, the chromatic aberration at position, and the distortion at the telephoto end of the zoom lens in this embodiment.

[0110] In this embodiment, a first lens group G1, a second lens group G2, an aperture stop, a third lens group G3, a fourth lens group G4, and an image plane Image are arranged sequentially from the object plane to the image plane along the optical axis. The first lens group G1 has positive optical power, the second lens group G2 has negative optical power, the third lens group G3 has positive optical power, and the fourth lens group G4 has positive optical power.

[0111] The first lens group G1 includes three lenses arranged sequentially along the optical axis from the object plane to the image plane: 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. Among them, the first lens L1 and the second lens L2 form a cemented lens.

[0112] The second lens group G2 includes three lenses arranged sequentially along the optical axis from the object plane to the image plane: a fourth lens L4 with negative optical power, a fifth lens L5 with negative optical power, and a sixth lens L6 with positive optical power. The object-side mirror surface of the fourth lens L4 is concave, the object-side mirror surface of the fifth lens L5 is concave, and the object-side mirror surface of the sixth lens L6 is convex.

[0113] The third lens group G3 comprises six lenses arranged sequentially along the optical axis from the object plane to the image plane: a seventh lens L7 with positive optical power, an eighth lens L8 with negative optical power, a ninth lens L9 with positive optical power, a tenth lens L10 with negative optical power, an eleventh lens L11 with positive optical power, and a twelfth lens L12 with negative optical power. The object-side surface of the seventh lens L7 is convex. The eighth and ninth lenses L8 and L9 form a cemented doublet, and the tenth, eleventh, and twelfth lenses L10, L11, and L12 form a cemented triplicate lens.

[0114] The fourth lens group G4 includes a thirteenth lens L13 with positive optical power, a fourteenth lens L14 with negative optical power, a fifteenth lens L15 with positive optical power, and a sixteenth lens L16 with negative optical power, arranged sequentially from the object plane to the image plane along the optical axis. The thirteenth lens L13 and the fourteenth lens L14 form a cemented doublet. The object-side mirror surface of the thirteenth lens L13 is convex, the image-side mirror surface of the fourteenth lens L14 is concave, and the object-side mirror surface of the sixteenth lens L16 is concave.

[0115] This embodiment meets the following requirements: total optical length (TTL): 124.3 mm; aperture value (Fno): 1.85; wide-angle focal length. 13.8mm; focal length at the telephoto end 35.1mm. The relevant parameters of each lens, including surface type, radius of curvature, thickness, refractive index of the material and Abbe number, are shown in Table 1. The units for radius of curvature and thickness are millimeters (mm).

[0116] Table 1

[0117]

[0118] In Table 1, each lens is considered to have two optical surfaces (object-side mirror and image-side mirror). For cemented lenses, two closely fitting surfaces with the same curvature are considered as one optical surface. The aperture stop is considered to have one optical surface (Stop), and the image plane is considered to have one optical surface (Image). Therefore, the zoom lens in this embodiment has a total of 29 optical surfaces. For ease of description, these 29 optical surfaces are arranged sequentially along the optical axis from the object surface to the image surface, according to the structural order of this application, and are numbered S1-S29.

[0119] In this embodiment, following the order from the object plane to the image plane along the optical axis, the seventh lens L7 is the first lens of the third lens group, and its refractive index is... The Abbe number is 1.91. The eleventh lens, L11, is the fifth lens in the third lens group, and its Abbe number is... The Abbe number is 95.10. The second lens L2 is the second lens in the first lens group, and its Abbe number is... It is 68.60.

[0120] In this embodiment, by changing the position of the second lens group G2 on the optical axis, moving it from the object plane to the image plane, the zoom lens can achieve continuous zoom from the wide-angle end to the telephoto end. At the same time, by cooperating with the adjustment of the position of the fourth lens group G4 on the optical axis, the zoom lens can focus clearly throughout the zoom process, with the image plane position remaining unchanged and maintaining high resolution.

[0121] Table 2 shows the air gaps on the optical axis of the first lens group G1 and the second lens group G2, the air gap on the optical axis of the second lens group G2 and the stop, the air gap on the optical axis of the third lens group G3 and the fourth lens group G4, and the air gap on the optical axis of the fourth lens group G4 and the image plane, D28, when the zoom lens is at the wide-angle end and the telephoto end, in millimeters (mm).

[0122] Table 2

[0123]

[0124] Based on the data in Tables 1 and 2 above, it can be seen that in this embodiment, the settings of the relevant parameters of each lens meet the requirements of the zoom lens of this application. And in conjunction with... Figures 1-8 In this embodiment, the zoom lens, through reasonable setting of lens position, material combination, and related parameters, effectively balances chromatic aberration, aberration, distortion, infrared performance, and high and low temperature performance, achieving excellent image quality at different focal lengths. Distortion is less than 5% throughout the zoom process, ensuring stable and reliable imaging in high and low temperature environments. It remains in focus in environments ranging from -40℃ to 80℃, while maintaining high-quality resolution at infrared wavelengths and clear imaging in low-light conditions at night.

[0125] Example 2:

[0126] The following is for reference Figures 9-16 This embodiment describes the zoom lens. Figure 9 This is a schematic diagram of the zoom lens at the wide-angle end in this embodiment. Figure 10 This is a schematic diagram of the zoom lens at the telephoto end in this embodiment. Figures 11-13 The images shown in sequence are chromatic aberration at magnification, positional chromatic aberration, and distortion at the wide-angle end of the zoom lens in this embodiment. Figures 14-16 The images shown are, in order, the chromatic aberration at magnification, the chromatic aberration at position, and the distortion at the telephoto end of the zoom lens in this embodiment.

[0127] In this embodiment, a first lens group G1, a second lens group G2, an aperture stop, a third lens group G3, a fourth lens group G4, and an image plane Image are arranged sequentially from the object plane to the image plane along the optical axis. The first lens group G1 has positive optical power, the second lens group G2 has negative optical power, the third lens group G3 has positive optical power, and the fourth lens group G4 has positive optical power.

[0128] The first lens group G1 includes three lenses arranged sequentially along the optical axis from the object plane to the image plane: 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. Among them, the first lens L1 and the second lens L2 form a cemented lens.

[0129] The second lens group G2 includes three lenses arranged sequentially along the optical axis from the object plane to the image plane: a fourth lens L4 with negative optical power, a fifth lens L5 with negative optical power, and a sixth lens L6 with positive optical power. The object-side mirror surface of the fourth lens L4 is concave, the object-side mirror surface of the fifth lens L5 is concave, and the object-side mirror surface of the sixth lens L6 is convex.

[0130] The third lens group G3 comprises six lenses arranged sequentially along the optical axis from the object plane to the image plane: a seventh lens L7 with positive optical power, an eighth lens L8 with negative optical power, a ninth lens L9 with positive optical power, a tenth lens L10 with negative optical power, an eleventh lens L11 with positive optical power, and a twelfth lens L12 with negative optical power. The object-side surface of the seventh lens L7 is convex. The eighth and ninth lenses L8 and L9 form a cemented doublet, and the tenth, eleventh, and twelfth lenses L10, L11, and L12 form a cemented triplicate lens.

[0131] The fourth lens group G4 includes a thirteenth lens L13 with positive optical power, a fourteenth lens L14 with negative optical power, a fifteenth lens L15 with positive optical power, and a sixteenth lens L16 with negative optical power, arranged sequentially from the object plane to the image plane along the optical axis. The thirteenth lens L13 and the fourteenth lens L14 form a cemented doublet. The object-side mirror surface of the thirteenth lens L13 is convex, the image-side mirror surface of the fourteenth lens L14 is concave, and the object-side mirror surface of the sixteenth lens L16 is concave.

[0132] This embodiment meets the following requirements: total optical length (TTL): 110mm; aperture value (Fno): 1.88; wide-angle focal length. 11mm; focal length at the telephoto end 30.8mm. The relevant parameters of each lens, including surface type, radius of curvature, thickness, refractive index of the material and Abbe number, are shown in Table 3. The units for radius of curvature and thickness are millimeters (mm).

[0133] Table 3

[0134]

[0135] In Table 3, each lens is considered to have two optical surfaces (object-side mirror and image-side mirror). For cemented lenses, two closely fitting surfaces with the same curvature are considered one optical surface. The aperture stop is considered to have one optical surface (Stop), and the image plane is considered to have one optical surface (Image). Therefore, the zoom lens in this embodiment has a total of 29 optical surfaces. For ease of description, these 29 optical surfaces are arranged sequentially along the optical axis from the object surface to the image surface, according to the structural order of this application, and are numbered S1-S29.

[0136] In this embodiment, following the order from the object plane to the image plane along the optical axis, the seventh lens L7 is the first lens of the third lens group, and its refractive index is... The Abbe number is 1.99. The eleventh lens, L11, is the fifth lens in the third lens group, and its Abbe number is... The Abbe number is 95.10. The second lens L2 is the second lens in the first lens group, and its Abbe number is... It is 54.50.

[0137] In this embodiment, by changing the position of the second lens group G2 on the optical axis, moving it from the object plane to the image plane, the zoom lens can achieve continuous zoom from the wide-angle end to the telephoto end. At the same time, by cooperating with the adjustment of the position of the fourth lens group G4 on the optical axis, the zoom lens can focus clearly throughout the zoom process, with the image plane position remaining unchanged and maintaining high resolution.

[0138] Table 4 shows the air gaps on the optical axis of the first lens group G1 and the second lens group G2, the air gap on the optical axis of the second lens group G2 and the stop, the air gap on the optical axis of the third lens group G3 and the fourth lens group G4, and the air gap on the optical axis of the fourth lens group G4 and the image plane, D28, when the zoom lens is at the wide-angle end and the telephoto end, in millimeters (mm).

[0139] Table 4

[0140]

[0141] According to the data in Tables 3 and 4 above, in this embodiment, the settings of the relevant parameters of each lens meet the requirements of the zoom lens of this application. And in conjunction with... Figures 9-16In this embodiment, the zoom lens, through reasonable settings of lens position, material combination, and related parameters, effectively balances chromatic aberration, aberration, distortion, infrared performance, and high and low temperature performance. Distortion is less than 5% throughout the zoom process, and excellent image quality is achieved at different focal lengths. It ensures stable and reliable imaging in high and low temperature environments, maintaining focus even in temperatures ranging from -40℃ to 80℃, while still providing high-quality resolution at infrared wavelengths and clear imaging in low-light conditions at night.

[0142] Example 3:

[0143] The following is for reference Figures 17-24 This embodiment describes the zoom lens. Figure 17 This is a schematic diagram of the zoom lens at the wide-angle end in this embodiment. Figure 18 This is a schematic diagram of the zoom lens at the telephoto end in this embodiment. Figures 19-21 The images shown in sequence are chromatic aberration at magnification, positional chromatic aberration, and distortion at the wide-angle end of the zoom lens in this embodiment. Figures 22-24 The images shown are, in order, the chromatic aberration at magnification, the chromatic aberration at position, and the distortion at the telephoto end of the zoom lens in this embodiment.

[0144] In this embodiment, a first lens group G1, a second lens group G2, an aperture stop, a third lens group G3, a fourth lens group G4, and an image plane Image are arranged sequentially from the object plane to the image plane along the optical axis. The first lens group G1 has positive optical power, the second lens group G2 has negative optical power, the third lens group G3 has positive optical power, and the fourth lens group G4 has positive optical power.

[0145] The first lens group G1 includes three lenses arranged sequentially along the optical axis from the object plane to the image plane: 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. Among them, the first lens L1 and the second lens L2 form a cemented lens.

[0146] The second lens group G2 includes three lenses arranged sequentially along the optical axis from the object plane to the image plane: a fourth lens L4 with negative optical power, a fifth lens L5 with negative optical power, and a sixth lens L6 with positive optical power. The object-side mirror surface of the fourth lens L4 is concave, the object-side mirror surface of the fifth lens L5 is concave, and the object-side mirror surface of the sixth lens L6 is convex.

[0147] The third lens group G3 comprises six lenses arranged sequentially along the optical axis from the object plane to the image plane: a seventh lens L7 with positive optical power, an eighth lens L8 with negative optical power, a ninth lens L9 with positive optical power, a tenth lens L10 with negative optical power, an eleventh lens L11 with positive optical power, and a twelfth lens L12 with negative optical power. The object-side surface of the seventh lens L7 is convex. The eighth and ninth lenses L8 and L9 form a cemented doublet, and the tenth, eleventh, and twelfth lenses L10, L11, and L12 form a cemented triplicate lens.

[0148] The fourth lens group G4 includes a thirteenth lens L13 with positive optical power, a fourteenth lens L14 with negative optical power, a fifteenth lens L15 with positive optical power, and a sixteenth lens L16 with negative optical power, arranged sequentially from the object plane to the image plane along the optical axis. The thirteenth lens L13 and the fourteenth lens L14 form a cemented doublet. The object-side mirror surface of the thirteenth lens L13 is convex, the image-side mirror surface of the fourteenth lens L14 is concave, and the object-side mirror surface of the sixteenth lens L16 is concave.

[0149] This embodiment meets the following requirements: total optical length (TTL): 120mm; aperture value (Fno): 1.81; wide-angle focal length. 14mm; focal length at the telephoto end 35.4mm. The relevant parameters of each lens, including surface type, radius of curvature, thickness, refractive index of the material and Abbe number, are shown in Table 5. The units for radius of curvature and thickness are millimeters (mm).

[0150] Table 5

[0151]

[0152] In Table 5, each lens is considered to have two optical surfaces (object-side mirror and image-side mirror). For cemented lenses, two closely fitting surfaces with the same curvature are considered as one optical surface. The aperture stop is considered to have one optical surface (Stop), and the image plane is considered to have one optical surface (Image). Therefore, the zoom lens in this embodiment has a total of 29 optical surfaces. For ease of description, these 29 optical surfaces are arranged sequentially along the optical axis from the object surface to the image surface, according to the structural order of this application, and are numbered S1-S29.

[0153] In this embodiment, following the order from the object plane to the image plane along the optical axis, the seventh lens L7 is the first lens of the third lens group, and its refractive index is... The Abbe number is 1.91. The eleventh lens, L11, is the fifth lens in the third lens group, and its Abbe number is... The Abbe number is 95.10. The second lens L2 is the second lens in the first lens group, and its Abbe number is... It is 68.60.

[0154] In this embodiment, by changing the position of the second lens group G2 on the optical axis, moving it from the object plane to the image plane, the zoom lens can achieve continuous zoom from the wide-angle end to the telephoto end. At the same time, by cooperating with the adjustment of the position of the fourth lens group G4 on the optical axis, the zoom lens can focus clearly throughout the zoom process, with the image plane position remaining unchanged and maintaining high resolution.

[0155] Table 6 shows the air gaps on the optical axis of the first lens group G1 and the second lens group G2, the air gap on the optical axis of the second lens group G2 and the stop, the air gap on the optical axis of the third lens group G3 and the fourth lens group G4, and the air gap on the optical axis of the fourth lens group G4 and the image plane, D28, when the zoom lens is at the wide-angle end and the telephoto end, in millimeters (mm).

[0156] Table 6

[0157]

[0158] According to the data in Tables 5 and 6 above, in this embodiment, the settings of the relevant parameters of each lens meet the requirements of the zoom lens of this application. And in conjunction with... Figures 17-24 In this embodiment, the zoom lens, through reasonable setting of lens position, material combination, and related parameters, effectively balances chromatic aberration, aberration, distortion, infrared performance, and high and low temperature performance, achieving excellent image quality at different focal lengths. Distortion is less than 5% throughout the zoom process, ensuring stable and reliable imaging in high and low temperature environments. It remains in focus in environments ranging from -40℃ to 80℃, while maintaining high-quality resolution at infrared wavelengths and clear imaging in low-light conditions at night.

[0159] The conditional expressions of the above Examples 1, 2, and 3 satisfy the following Table 7.

[0160] Table 7

[0161]

[0162] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0163] The embodiments described above are merely specific and detailed examples of the embodiments described in this application, and should not be construed as limiting the scope of the application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the appended claims.

Claims

1. A zoom lens, characterized in that: It includes a first lens group with positive optical power, a second lens group with negative optical power, an aperture stop, a third lens group with positive optical power, and a fourth lens group with positive optical power, arranged sequentially from the object plane to the image plane along the optical axis, wherein: The first and third lens groups are fixed groups, the second lens group is a zoom group to achieve zoom from wide-angle end to telephoto end by moving from the object plane to the image plane along the optical axis, and the fourth lens group is a focusing group to move and zoom along the optical axis. The zoom lens also meets the following conditions: 2.5≤ ≤5； in, The total optical length of the zoom lens is in mm. The distance on the axis is from the mirror closest to the object plane when the second lens group is at the wide-angle end to the mirror closest to the image plane when the second lens group is at the telephoto end, in mm.

2. The zoom lens as described in claim 1, characterized in that: The first lens group includes a first lens with negative optical power, a second lens with positive optical power, and a third lens with positive optical power arranged sequentially from the object plane to the image plane along the optical axis, and the first lens and the second lens form a first cemented doublet lens group. The second lens group includes a fourth lens with negative optical power, a fifth lens with negative optical power, and a sixth lens with positive optical power, arranged sequentially from the object plane to the image plane along the optical axis. The third lens group includes a seventh lens with positive optical power, an eighth lens with negative optical power, a ninth lens with positive optical power, a tenth lens with negative optical power, an eleventh lens with positive optical power, and a twelfth lens with negative optical power, arranged sequentially from the object plane to the image plane along the optical axis. The eighth and ninth lenses form a second cemented doublet lens group, and the tenth, eleventh, and twelfth lenses form a first cemented triplet lens group. The fourth lens group includes a thirteenth lens with positive optical power, a fourteenth lens with negative optical power, a fifteenth lens with positive optical power, and a sixteenth lens with negative optical power arranged sequentially from the object plane to the image plane along the optical axis, and the thirteenth lens and the fourteenth lens form a third cemented doublet lens group.

3. The zoom lens as described in claim 2, characterized in that: The image-side mirror of the fourth lens is concave, the object-side mirror of the fifth lens is concave, the object-side mirror of the sixth lens is convex, the object-side mirror of the seventh lens is convex, the object-side mirror of the eighth lens is concave, the image-side mirror of the twelfth lens is convex, the object-side mirror of the thirteenth lens is convex, the image-side mirror of the fourteenth lens is concave, and the object-side mirror of the sixteenth lens is concave.

4. The zoom lens as described in claim 1, characterized in that: The zoom lens also meets the following conditions: 5.5≤ ≤9； in, The diameter of the maximum imaging surface of the zoom lens is in mm.

5. The zoom lens as described in claim 1, characterized in that: The zoom lens also meets the following conditions: 4.5≤ ≤7； in, The focal length of the zoom lens when it is at the telephoto end, in mm; The focal length of the zoom lens at its wide-angle end is in mm.

6. The zoom lens as described in claim 1, characterized in that: The zoom lens also meets the following conditions: 1.5≤ ≤2.2； in, The focal length of the zoom lens when it is at the telephoto end, in mm; The focal length of the zoom lens at its wide-angle end is in mm.

7. The zoom lens as described in claim 1, characterized in that: The zoom lens also meets the following conditions: 2≤ ≤4.5； in, The focal length of the third lens group is in mm; The focal length of the zoom lens at its wide-angle end is in mm.

8. The zoom lens as described in claim 1, characterized in that: The zoom lens also meets the following conditions: 0.4≤ ≤0.9； in, The focal length of the second lens group is in mm; The focal length of the zoom lens at its telephoto end is expressed in mm.

9. The zoom lens as described in claim 1, characterized in that: The zoom lens also meets the following conditions: 0.6≤ ≤1.5； in, The focal length of the zoom lens when it is at the telephoto end, in mm; The object-side aperture of the first lens closest to the object plane in the first lens group is half the diameter, in mm.

10. The zoom lens as described in claim 1, characterized in that: The first lens group has one lens with an Abbe number of 50 to 95; the first lens in the third lens group closest to the object surface has a refractive index of 1.8 to 2.2, and at least one lens in the third lens group has an Abbe number of 60 to 95.

Images