Zoom lens

Abstract

The present invention discloses a zoom lens, comprising a first fixed lens group, a first zoom lens group, a second zoom lens group, a focus lens group and a second fixed lens group arranged in sequence from an object plane to an image plane along an optical axis; the first fixed lens group has a positive focal length, the first zoom lens group has a negative focal length, the second zoom lens group has a positive focal length, the focus lens group has a positive focal length, and the second fixed lens group has a negative focal length. The zoom lens provided by an embodiment of the present invention adopts a five-element structure and uses 14 lenses. By setting the number of lenses in each lens group and further limiting the collocation of the focal lengths of each lens group and each lens, a zoom lens with a large target surface, a large magnification, a large aperture, a small distortion and a small volume is realized, which can meet a wider range of usage requirements.

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 the security field, zoom lenses have been widely used due to their advantages such as long shooting distance, continuous and rapid magnification change, and the ability to achieve good shooting effects in different usage scenarios. With the development of technology, cameras are gradually moving towards miniaturization and refinement, which also puts more stringent requirements on mainstream zoom lenses.

[0003] At present, in order to achieve a wider range of applications, 1 / 1.8” photosensitive chips have gradually become the mainstream chips on the market, but traditional zoom lenses usually 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, small magnification, and large distortion. Summary of the invention

[0004] The invention provides a zoom lens to realize a zoom lens with a large target surface, a large magnification, a large aperture and small distortion.

[0005] The present invention provides a zoom lens, comprising a first fixed lens group, a first magnification lens group, a second magnification lens group, a focus lens group and a second fixed lens group, which are arranged in sequence from an object plane to an image plane along an optical axis;

[0006] The first fixed lens group and the second fixed lens group are fixedly arranged, and the first variable magnification lens group, the second variable magnification lens group and the focus lens group are movably arranged along the optical axis direction;

[0007] The first fixed lens group has positive optical power, the first zoom lens group has negative optical power, the second zoom lens group has positive optical power, the focus lens group has positive optical power, and the second fixed lens group has negative optical power;

[0008] The first fixed lens group includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence from the object plane to the image plane; the first lens has a negative optical power, the second lens has a positive optical power, the third lens has a positive optical power, and the fourth lens has a positive optical power;

[0009] The first zoom lens group includes a fifth lens, a sixth lens and a seventh lens arranged in sequence from the object plane to the image plane; the fifth lens has a negative optical power, the sixth lens has a negative optical power, and the seventh lens has a positive optical power;

[0010] The second zoom lens group includes an eighth lens, a ninth lens, a tenth lens and an eleventh lens arranged in sequence from the object plane to the image plane; the eighth lens has a positive optical power, the ninth lens has a positive optical power, the tenth lens has a negative optical power, and the eleventh lens has a positive optical power;

[0011] The focusing lens group includes a twelfth lens and a thirteenth lens arranged in sequence from the object plane to the image plane; the twelfth lens has a positive optical power, and the thirteenth lens has a negative optical power;

[0012] The second fixed lens group includes a fourteenth lens; the fourteenth lens has negative optical power.

[0013] Optionally, the first lens and the second lens form a first cemented lens group;

[0014] The ninth lens and the tenth lens form a second cemented lens group.

[0015] Optionally, the focal length of the first fixed lens group is FG1, the focal length of the first variator group is FG2, the focal length of the second variator group is FG3, the focal length of the focus lens group is FG4, the focal length of the second fixed lens group is FG5, and the focal length of the zoom lens at the wide-angle end is FW;

[0016] 5.365≤FG1 / FW≤6.339;

[0017] -1.289≤FG2 / FW≤-0.878;

[0018] 2.949≤FG3 / FW≤3.769;

[0019] 2.405≤FG4 / FW≤2.897;

[0020] -14.214≤FG5 / FW≤-6.978.

[0021] Optionally, the first lens and the second lens form a first cemented lens group;

[0022] The focal length of the first lens is F1, the focal length of the first cemented lens group is F101, 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;

[0023] -0.536≤F1 / F101≤0.478;

[0024] 23.654≤|F101 / (FT / FW)|≤34.249.

[0025] 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;

[0026] 6.354≤(FT-FW) / (FT / FW)≤7.421.

[0027] Optionally, the sixth lens, the eleventh lens, the twelfth lens and the fourteenth lens are all glass aspherical lenses;

[0028] The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens and the thirteenth lens are all glass spherical lenses.

[0029] Optionally, the refractive index of the sixth lens is Nd1, and the Abbe number is Vd1; the refractive index of the eleventh lens is Nd2, and the Abbe number is Vd2; the refractive index of the twelfth lens is Nd3, and the Abbe number is Vd3; the refractive index of the fourteenth lens is Nd4, and the Abbe number is Vd4;

[0030] 1.45≤Nd1≤1.51; 20.00≤Vd1≤95.00;

[0031] 1.45≤Nd2≤1.51; 20.00≤Vd2≤95.00;

[0032] 1.45≤Nd3≤1.50; 20.00≤Vd3≤95.00;

[0033] 1.54≤Nd4≤1.66;20.00≤Vd4≤95.00.

[0034] 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; the optical distortion of the zoom lens at the wide-angle end is DIS1, and the optical distortion of the zoom lens at the telephoto end is DIS2;

[0035] 14.600≤FT / FW≤19.954;

[0036] 2.428≤|FW / DIS1|≤4.189;

[0037] 26.667≤|FT / DIS2|≤55.922.

[0038] Optionally, the maximum movable distance of the first variator group is D2, the maximum movable distance of the second variator group is D3, the maximum movable distance of the focus lens group is D4, and the total optical length of the zoom lens is TTL;

[0039] 0.245≤D2 / TTL≤0.376;

[0040] 0.068≤D3 / TTL≤0.087;

[0041] 0.058≤D4 / TTL≤0.096.

[0042] Optionally, the image plane size of the zoom lens is HI, and the total optical length of the zoom lens is TTL;

[0043] 0.045≤HI / TTL≤0.106.

[0044] The zoom lens provided in the embodiment of the present invention adopts a five-element structure and uses 14 lenses. By setting the number of lenses in five lens groups and further limiting the focal power matching of the five lens groups and the 14 lenses, the zoom lens has an optical total length TTL of TTL≤100mm and a focal length F of 7mm≤F≤130mm under a 1 / 1.8″ target surface, and a magnification of nearly 20 times, an aperture number F / # of 1.63, and a distortion of less than 10% under a wavelength band of 436nm~656nm, thereby realizing a zoom lens with a large target surface, a large magnification, a large aperture, a small distortion, and a small size, which can meet a wider range of usage requirements.

[0045] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] 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.

[0047] Figure 1 A schematic diagram of the structure of a zoom lens at the wide-angle end provided by an embodiment of the present invention;

[0048] Figure 2 A schematic diagram of the structure of a zoom lens at the telephoto end provided by an embodiment of the present invention;

[0049] Figure 3 A schematic diagram of the structure of another zoom lens at the wide-angle end provided by an embodiment of the present invention;

[0050] Figure 4 A schematic diagram of the structure of another zoom lens at the telephoto end provided by an embodiment of the present invention;

[0051] Figure 5 A schematic diagram of the structure of another zoom lens at the wide-angle end provided by an embodiment of the present invention;

[0052] Figure 6 A schematic diagram of the structure of another zoom lens at the telephoto end provided by an embodiment of the present invention;

[0053] Figure 7 A field curvature distortion diagram of the zoom lens provided in the first embodiment of the present invention at the wide-angle end;

[0054] Figure 8 A field curvature distortion diagram of the zoom lens provided in the first embodiment of the present invention at the telephoto end;

[0055] Figure 9-14 Light fan diagrams of the zoom lens provided in Embodiment 1 of the present invention at different field angles at the wide-angle end;

[0056] Figure 15-Figure 20 Light fan diagrams of the zoom lens provided in the first embodiment of the present invention at different field angles at the telephoto end;

[0057] Fig.21 A vertical axis chromatic aberration diagram of the zoom lens provided in the first embodiment of the present invention at the wide-angle end;

[0058] Fig. 22 A vertical axis chromatic aberration diagram of the zoom lens provided in the first embodiment of the present invention at the telephoto end;

[0059] Fig.23 A field curvature distortion diagram of the zoom lens provided in the second embodiment of the present invention at the wide-angle end;

[0060] Fig.24 A field curvature distortion diagram of the zoom lens at the telephoto end provided by the second embodiment of the present invention;

[0061] Figure 25-Figure 30 Light fan diagrams of the zoom lens provided in the second embodiment of the present invention at different field angles at the wide-angle end;

[0062] Figure 31-Figure 36 Light fan diagrams of the zoom lens provided in the second embodiment of the present invention at different field angles at the telephoto end;

[0063] Fig.37 A vertical axis chromatic aberration diagram of the zoom lens provided in the second embodiment of the present invention at the wide-angle end;

[0064] Fig.38 A vertical axis chromatic aberration diagram of the zoom lens provided in the second embodiment of the present invention at the telephoto end;

[0065] Fig.39 A field curvature distortion diagram of the zoom lens provided in Embodiment 3 of the present invention at the wide-angle end;

[0066] Fig.40 A field curvature distortion diagram of the zoom lens at the telephoto end provided by the third embodiment of the present invention;

[0067] Figure 41-46 Light fan diagrams of the zoom lens provided in Embodiment 3 of the present invention at different field angles at the wide-angle end;

[0068] Figure 47-Figure 52 Light fan diagrams of the zoom lens provided in Embodiment 3 of the present invention at different field angles at the telephoto end;

[0069] Fig.53 A vertical axis chromatic aberration diagram of the zoom lens provided in Embodiment 3 of the present invention at the wide-angle end;

[0070] Fig.54 This is a diagram of vertical axis chromatic aberration of the zoom lens provided in Embodiment 3 of the present invention at the telephoto end. DETAILED DESCRIPTION

[0071] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0072] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations 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 that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0073] Figure 1 A schematic diagram of the structure of a zoom lens at the wide-angle end provided by an embodiment of the present invention, Figure 2 A schematic diagram of the structure of a zoom lens at the telephoto end provided by an embodiment of the present invention; Figure 3 A schematic diagram of the structure of another zoom lens at the wide-angle end provided by an embodiment of the present invention, Figure 4 A schematic diagram of the structure of another zoom lens at the telephoto end provided by an embodiment of the present invention; Figure 5A schematic diagram of the structure of another zoom lens at the wide-angle end provided by an embodiment of the present invention, Figure 6 A schematic diagram of the structure of another zoom lens at the telephoto end provided by an embodiment of the present invention; Figure 1-Figure 6 As shown, the zoom lens provided by the embodiment of the present invention includes a first fixed lens group G1, a first magnification lens group G2, a second magnification lens group G3, a focus lens group G4 and a second fixed lens group G5 which are arranged in sequence from the object plane to the image plane along the optical axis.

[0074] The first fixed lens group G1 and the second fixed lens group G5 are fixedly arranged, and the first variator group G2, the second variator group G3 and the focus lens group G4 are movable along the optical axis direction.

[0075] The first fixed lens group G1 has positive power, the first variator group G2 has negative power, the second variator group G3 has positive power, the focus lens group G4 has positive power, and the second fixed lens group G5 has negative power.

[0076] The first fixed lens group G1 includes a first lens L1, a second lens L2, a third lens L3 and a fourth lens L4 arranged in sequence from the object plane to the image plane; the first lens L1 has negative refractive power, the second lens L2 has positive refractive power, the third lens L3 has positive refractive power, and the fourth lens L4 has positive refractive power.

[0077] The first zoom lens group G2 includes a fifth lens L5, a sixth lens L6 and a seventh lens L7 which are arranged in sequence from the object plane to the image plane; the fifth lens L5 has negative refractive power, the sixth lens L6 has negative refractive power, and the seventh lens L7 has positive refractive power.

[0078] The second variator group G3 includes an eighth lens L8, a ninth lens L9, a tenth lens L10 and an eleventh lens L11 arranged in sequence from the object plane to the image plane; the eighth lens L8 has positive refractive power, the ninth lens L9 has positive refractive power, the tenth lens L10 has negative refractive power, and the eleventh lens L11 has positive refractive power.

[0079] The focusing lens group G4 includes a twelfth lens L12 and a thirteenth lens L13 which are sequentially arranged from the object plane to the image plane. The twelfth lens L12 has positive refractive power, and the thirteenth lens L13 has negative refractive power.

[0080] The second fixed lens group G5 includes a fourteenth lens L14; the fourteenth lens L14 has negative refractive power.

[0081] Specifically, Figure 1-Figure 6As shown, the zoom lens provided by the embodiment of the present invention is arranged in sequence along the optical axis from the object side to the image side: a first fixed lens group G1 with positive optical focal length, a first zoom lens group G2 with negative optical focal length, a second zoom lens group G3 with positive optical focal length, a focus lens group G4 with positive optical focal length, and a second fixed lens group G5 with negative optical focal length.

[0082] The first fixed lens group G1 , the first variator lens group G2 , the second variator lens group G3 , the focus lens group G4 and the second fixed lens group G5 may be arranged in one lens barrel (not shown in the figure), but the present invention is not limited thereto.

[0083] Furthermore, the first fixed lens group G1 and the second fixed lens group G5 may be fixed in position in the lens barrel, so that the first fixed lens group G1 and the second fixed lens group G5 are immovable relative to the image plane.

[0084] The first magnification lens group G2, the second magnification lens group G3 and the focus lens group G4 can move back and forth along the optical axis in the lens barrel, wherein moving the first magnification lens group G2 and the second magnification lens group G3 can achieve a zooming effect, and moving the focus lens group G4 can achieve a focusing effect, and by changing the positions of the first magnification lens group G2, the second magnification lens group G3 and the focus lens group G4 on the optical axis, the zoom lens can be switched between the wide-angle end and the telephoto end.

[0085] Among them, in the process of achieving zooming by changing the positions of the first magnification lens group G2, the second magnification lens group G3 and the focus lens group G4 on the optical axis, the zoom lens is at the wide-angle end when the focal length is the shortest, and is at the telephoto end when the focal length is the longest. At the wide-angle end and the telephoto end, the zoom lens has different focal lengths and optical focal powers.

[0086] Specifically, the focal length 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 the optical system to deflect light. The larger the absolute value of the focal length, the stronger the ability to bend light, and the smaller the absolute value of the focal length, the weaker the ability to bend light. When the focal length is a positive number, the refraction of light is convergent; when the focal length is a negative number, the refraction of light is divergent. The focal length can be used to characterize a refractive surface of a lens (i.e., a surface of a lens), can be used to characterize a lens, or can be used to characterize a system formed by multiple lenses (i.e., a lens group).

[0087] In the embodiment of the present invention, the optical focal length of the first fixed lens group G1 is positive, and the light can be converged to a certain extent; the optical focal length of the first zoom lens group G2 is negative, so that after the light is initially converged by the first fixed lens group G1, it is appropriately diverged by the first zoom lens group G2 to adjust the light path, ensure that the light can enter the subsequent structure, and better control the degree of contraction of the light in the subsequent structure to adapt to different focal length requirements.

[0088] Furthermore, the first fixed lens group G1, the first zoom lens group G2, the second zoom lens group G3, the focusing lens group G4 and the second fixed lens group G5 adopt a positive-negative-positive-positive-negative optical focal length combination, so that the light can be reasonably converged and diverged when passing through each lens group, ensuring that the light will not be deflected too much and pass smoothly through the entire lens system. Such a setting can not only achieve a longer focal length, but also maintain good imaging quality at different focal lengths.

[0089] Continue to refer Figure 1-Figure 6 The number of lenses with optical power in the first fixed lens group G1 can be 4, wherein the first fixed lens group G1 can be composed of a first lens L1 with negative optical power, a second lens L2 with positive optical power, a third lens L3 with positive optical power, and a fourth lens L4 with positive optical power.

[0090] The number of lenses with optical power in the first zoom lens group G2 may be 3, wherein the first zoom lens group G2 may be composed of a fifth lens L5 with negative optical power, a sixth lens L6 with negative optical power, and a seventh lens L7 with positive optical power.

[0091] The number of lenses with optical power in the second zoom lens group G3 can be 4, wherein the second zoom lens group G3 can be composed of an eighth lens L8 with positive optical power, a ninth lens L9 with positive optical power, a tenth lens L10 with negative optical power, and an eleventh lens L11 with positive optical power.

[0092] Among them, the second zoom lens group G3 can help correct higher-order aberrations more finely by using a larger number of lenses (4 lenses), thereby improving image quality.

[0093] The number of lenses with optical power in the focus lens group G4 may be 2, wherein the focus lens group G4 may be composed of a twelfth lens L12 with positive optical power and a thirteenth lens L13 with negative optical power.

[0094] Among them, the focus lens group G4 is beneficial to improving the focusing effect and improving the focusing sensitivity by using a smaller number of lenses (2 lenses). For example, the focus lens group G4 uses only 2 lenses, which can make the focus lens group G4 lighter, thereby reducing the moving inertia, so that the focus lens group G4 can move to the correct position quickly and accurately, which is beneficial to improving the focusing response speed, focusing sensitivity and focusing accuracy. In addition, the focus lens group G4 is also beneficial to reducing the manufacturing cost and complexity of the zoom lens by using a smaller number of lenses.

[0095] Furthermore, the focus lens group G4 uses two lenses, which is also beneficial for correcting high-order aberrations, thereby improving image quality.

[0096] The number of lenses with optical power in the second fixed lens group G5 may be one, wherein the second fixed lens group G5 may consist of a fourteenth lens L14 with negative optical power.

[0097] In the embodiment of the present invention, a five-element structure is adopted, 14 lenses are used, the number of lenses in 5 lens groups is set, and the optical power matching of the 5 lens groups and the 14 lenses is further limited, so that the zoom lens has a total optical length TTL of TTL≤100mm under a 1 / 1.8″ target surface, a focal length F satisfies 7mm≤F≤130mm, and a magnification of nearly 20 times, an aperture number F / # of 1.63, and a distortion of less than 10% under a wavelength band of 436nm~656nm, thereby realizing a zoom lens with a large target surface, a large magnification, a large aperture, a small distortion, and a small size, which can meet a wider range of usage requirements.

[0098] As a feasible implementation method, continue to refer to Figure 1-Figure 6 In the first fixed lens group G1, the object-side surface of the first lens L1 is convex; the object-side surface of the second lens L2 is convex, and the image-side surface is convex; the object-side surface of the third lens L3 is convex, and the image-side surface is concave; the object-side surface of the fourth lens L4 is convex, and the image-side surface is concave.

[0099] In the first zoom lens group G2, the object-side surface of the fifth lens L5 is convex, and the image-side surface is concave; the object-side surface of the sixth lens L6 is concave, and the image-side surface is concave; the object-side surface of the seventh lens L7 is convex, and the image-side surface is convex.

[0100] In the second variator group G3, the object-side surface of the eighth lens L8 is convex, and the image-side surface is concave; the object-side surface of the ninth lens L9 is convex; the object-side surface of the tenth lens L10 is concave, and the image-side surface is concave; the object-side surface of the eleventh lens L11 is convex, and the image-side surface is concave.

[0101] In the focusing lens group G4, the object-side surface of the twelfth lens L12 is convex; the object-side surface of the thirteenth lens L13 is concave, and the image-side surface is convex.

[0102] In the second fixed lens group G5, the object-side surface of the fourteenth lens L14 is concave, and the image-side surface is convex.

[0103] Among them, the surface shape of the lens affects the propagation direction of light and determines how the light bends when passing through the lens, which in turn affects the maximum aperture and light transmittance of the lens, as well as the quality and characteristics of the imaging.

[0104] In this embodiment, by reasonably matching the surface shapes of each lens, while meeting the requirements of the optical power of each lens and achieving the required optical performance indicators (such as large target surface, large magnification, large aperture, small distortion, and small volume), it is beneficial to further reduce the total optical length of the entire zoom lens, thereby realizing a miniaturized lens design. In addition, while ensuring a large aperture, the path of light passing through the entire zoom lens is made smoother, and unnecessary reflections and absorption are reduced, thereby achieving a long focal length and improving the light throughput and imaging quality.

[0105] Continue to refer Figure 1-Figure 6 As a feasible implementation, the zoom lens further includes a stop STO, and the stop STO is located in the optical path between the seventh lens L7 and the eighth lens L8.

[0106] Among them, the aperture STO is set in the optical path between the seventh lens L7 and the eighth lens L8, so that the aperture STO can be closer to the front end of the zoom lens, so as to control the distribution of light entering the subsequent lenses through the aperture STO to optimize aberrations such as astigmatism and coma, so that high-order aberrations are well controlled at the front end of the zoom lens, ensuring that the image height is increased and the target surface is expanded at the rear end of the zoom lens while also having good imaging quality, thereby meeting the usage requirements in more situations.

[0107] Continue to refer Figure 1-Figure 5 As a feasible implementation, the zoom lens may further include a flat glass P, which is located on the image side of the fourteenth lens L14. The flat glass P can protect the photosensitive chip, thereby ensuring the imaging effect of the zoom lens. The photosensitive chip is used to convert the light signal collected by the zoom lens into an electrical signal, which can then generate a digital image or video from the electrical signal through a series of processing steps.

[0108] Continue to refer Figure 1-Figure 6 As a feasible implementation manner, the first lens L1 and the second lens L2 form a first cemented lens group g1; the ninth lens L9 and the tenth lens L10 form a second cemented lens group g2.

[0109] Among them, Figure 1-Figure 6 As shown, by gluing the first lens L1 and the second lens L2, and gluing the ninth lens L9 and the tenth lens L10, chromatic aberration can be minimized or eliminated, so that the chromatic aberration of the zoom lens is fully corrected. At the same time, the air interval between the first lens L1 and the second lens L2, and the ninth lens L9 and the tenth lens L10 can be effectively reduced, thereby further reducing the total optical length of the lens.

[0110] In addition, the first lens L1 and the second lens L2 are cemented together, and the ninth lens L9 and the tenth lens L10 are cemented together, which can also reduce the air interface, thereby reducing the reflection loss, and can also reduce the assembly components between the first lens L1 and the second lens L2, and between the ninth lens L9 and the tenth lens L10, simplifying the assembly procedure in the lens manufacturing process, reducing costs, and reducing the influence of lens tolerances such as tilt / eccentricity generated during the assembly process on the zoom lens, thereby improving the stability of the zoom lens.

[0111] Continue to refer Figure 1-Figure 6 As a feasible implementation, the focal length of the first fixed lens group G1 is FG1, the focal length of the first variator group G2 is FG2, the focal length of the second variator group G3 is FG3, the focal length of the focus lens group G4 is FG4, the focal length of the second fixed lens group G5 is FG5, and the focal length of the zoom lens at the wide-angle end is FW, wherein 5.365≤FG1 / FW≤6.339; -1.289≤FG2 / FW≤-0.878; 2.949≤FG3 / FW≤3.769; 2.405≤FG4 / FW≤2.897; -14.214≤FG5 / FW≤-6.978.

[0112] Among them, by further limiting the focal length of each lens group, it is possible to achieve a reasonable combination of the optical power of each lens, so that light can pass through the zoom lens more smoothly, thereby being able to correct the high-order aberrations of the zoom lens to a greater extent, while achieving a longer focal length, it can also maintain good imaging quality at different focal lengths.

[0113] Continue to refer Figure 1-Figure 6 As a feasible implementation, the first lens L1 and the second lens L2 form a first cemented lens group g1; the focal length of the first lens L1 is F1, the focal length of the first cemented lens group g1 is F101, 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, -0.536≤F1 / F101≤0.478; 23.654≤|F101 / (FT / FW)|≤34.249.

[0114] Specifically, the first lens L1 and the second lens L2 are cemented together to form a first cemented lens group g1 with positive refractive power, which can better correct chromatic aberration while ensuring that light can enter the subsequent structure.

[0115] Furthermore, by setting the focal length F101 of the first cemented lens group g1 and the focal length F1 of the first lens L1 to satisfy -0.536≤F1 / F101≤0.478, the focal length of the first lens L1 is ensured to be moderate, which can make the object side light enter the imaging system more smoothly and reduce the rapid change of light in the subsequent lens groups, so that high-order aberrations can be corrected to a greater extent.

[0116] Furthermore, the focal length F101 of the first cemented lens group g1, the focal length FW of the zoom lens at the wide-angle end, and the focal length FT of the zoom lens at the telephoto end satisfy 23.654≤|F101 / (FT / FW)|≤34.249, wherein FT / FW can be understood as the zoom ratio. By limiting the ratio range between the focal length F101 of the first cemented lens group g1 and the zoom ratio FT / FW, it can be ensured that the zoom lens can achieve a higher magnification between the wide-angle end and the telephoto end (for example, the magnification can reach 20 times or more). At the same time, it can also make the light distributed more widely when reaching the photosensitive chip (target surface), which is beneficial to expand the target surface size of the zoom lens.

[0117] As a feasible implementation, 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 6.354≤(FT-FW) / (FT / FW)≤7.421.

[0118] Among them, if the ratio (FT-FW) / (FT / FW) is less than 6.354, the focal length of the zoom lens at the telephoto end is short and the required magnification (for example, the magnification reaches 20 times) cannot be achieved; if the ratio (FT-FW) / (FT / FW) is greater than 7.421, the high-order chromatic aberration of the zoom lens at the full focal length is difficult to correct, the resolution of the zoom lens is reduced, and the total optical length of the zoom lens is difficult to compress.

[0119] Therefore, in this embodiment, the focal length FW of the zoom lens at the wide-angle end and the focal length FT at the telephoto end are set to satisfy 6.354≤(FT-FW) / (FT / FW)≤7.421, so that when the zoom lens moves from the wide-angle end to the telephoto end, the focal length changes within a certain range, ensuring that the zoom lens can provide sufficient magnification at the telephoto end (for example, a magnification of 20 times), while also maintaining good chromatic aberration correction capability and resolution throughout the entire zoom range, and helping to control the overall length of the zoom lens.

[0120] As a feasible implementation manner, the sixth lens L6, the eleventh lens L11, the twelfth lens L12 and the fourteenth lens L14 are all glass aspherical lenses.

[0121] The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the seventh lens L7, the eighth lens L8, the ninth lens L9, the tenth lens L10 and the thirteenth lens L13 are all glass spherical lenses.

[0122] Specifically, the zoom lens provided by the embodiment of the present invention includes at least four glass aspherical lenses, which can correct the geometric aberrations of the zoom lens, such as spherical aberration, coma and astigmatism, so as to improve the imaging quality of the entire zoom lens.

[0123] Among them, at least one glass aspherical lens can be set in the first zoom lens group G2, the second zoom lens group G3, the focusing lens group G4 and the second fixed lens group G5, so that the spherical aberration and higher-order aberration of the above lens groups can be better corrected, thereby improving the clarity of the image under high magnification conditions.

[0124] In the embodiment of the present invention, the sixth lens L6, the eleventh lens L11, the twelfth lens L12 and the fourteenth lens L14 are set as glass aspherical lenses, so that the distribution of glass aspherical lenses in the zoom lens can be more uniform, so that aberrations can be effectively corrected in the entire zoom range, ensuring that good imaging quality can be maintained at different focal lengths. At the same time, the uniformly distributed aspherical lenses can better coordinate the optical performance of the entire lens system, reduce local aberration accumulation, and improve the overall imaging quality.

[0125] Meanwhile, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the seventh lens L7, the eighth lens L8, the ninth lens L9, the tenth lens L10 and the thirteenth lens L13 are all glass spherical lenses, which helps to reduce costs and is easy to manufacture.

[0126] Furthermore, all lenses in the zoom lens are made of glass lenses, wherein glass lenses have higher transmittance, which can reduce the loss of light energy, so that the light energy received by the photosensitive chip is higher, which is conducive to better imaging effects in dark light environments.

[0127] At the same time, glass lenses have the advantages of high hardness, strong wear resistance, long service life and not easily deformed by temperature, which can make the performance of the zoom lens more stable.

[0128] As a feasible implementation manner, the refractive index of the sixth lens L6 is Nd1, and the Abbe number is Vd1; the refractive index of the eleventh lens L11 is Nd2, and the Abbe number is Vd2; the refractive index of the twelfth lens L12 is Nd3, and the Abbe number is Vd3; the refractive index of the fourteenth lens L14 is Nd4, and the Abbe number is Vd4; wherein:

[0129] 1.45≤Nd1≤1.51; 20.00≤Vd1≤95.00;

[0130] 1.45≤Nd2≤1.51; 20.00≤Vd2≤95.00;

[0131] 1.45≤Nd3≤1.50; 20.00≤Vd3≤95.00;

[0132] 1.54≤Nd4≤1.66;20.00≤Vd4≤95.00.

[0133] Among them, the refractive index is the ratio of the speed of light in a vacuum to the speed of light in the medium. It is mainly used to describe the material's ability to refract light. Different materials have different refractive indices.

[0134] The Abbe number is an index used to indicate the dispersion ability of a transparent medium. The more severe the dispersion of the medium, the smaller the Abbe number; conversely, the less severe the dispersion of the medium, the larger the Abbe number.

[0135] In this embodiment, by reasonably limiting the refractive index and Abbe number of the sixth lens L6, the eleventh lens L11, the twelfth lens L12 and the fourteenth lens L14, spherical aberration and higher-order aberrations can be corrected to a greater extent, which is beneficial to eliminating distortion in the telephoto end image.

[0136] At the same time, since the above-mentioned aspherical lens has good aberration correction capability, it is also beneficial to reduce the total number of lenses required in the zoom lens, thereby simplifying the lens design, reducing the weight, and compressing the size of the lens.

[0137] As a feasible implementation, 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; the optical distortion of the zoom lens at the wide-angle end is DIS1, and the optical distortion of the zoom lens at the telephoto end is DIS2; wherein:

[0138] 14.600≤FT / FW≤19.954;

[0139] 2.428≤|FW / DIS1|≤4.189;

[0140] 26.667≤|FT / DIS2|≤55.922.

[0141] In this embodiment, by reasonably limiting the ratio between the focal length FW of the zoom lens at the wide-angle end and the focal length FT at the telephoto end, and reasonably limiting the ratio between the focal length of the zoom lens at the wide-angle end and the telephoto end and the corresponding distortion, the zoom lens can achieve a magnification ratio of nearly 20 times, and while ensuring a large magnification ratio and a large target surface, the distortion can be controlled within a reasonable range, so that the details of the desired imaging picture can be better magnified and a good imaging effect can be maintained.

[0142] As a feasible implementation, the maximum movable distance of the first zoom lens group G2 is D2, the maximum movable distance of the second zoom lens group G3 is D3, the maximum movable distance of the focus lens group G4 is D4, and the total optical length of the zoom lens is TTL; wherein:

[0143] 0.245≤D2 / TTL≤0.376;

[0144] 0.068≤D3 / TTL≤0.087;

[0145] 0.058≤D4 / TTL≤0.096.

[0146] The total length TTL of the zoom lens refers to the distance from the center of the optical axis of the object-side surface of the first lens L1 to the image plane.

[0147] In this embodiment, the maximum movable distance D2 of the first zoom lens group G2 and the total optical length TTL of the zoom lens satisfy 0.245≤D2 / TTL≤0.376, ensuring that the first zoom lens group G2 can move effectively during the zooming process to achieve the zoom function from wide angle to telephoto. At the same time, the movement of the first zoom lens group G2 will not occupy too much of the total length of the lens, thereby helping to reduce the size of the lens.

[0148] The maximum movable distance D3 of the second zoom lens group G3 and the total optical length TTL of the zoom lens satisfy 0.068≤D3 / TTL≤0.087, ensuring that the second zoom lens group G3 can be effectively moved during the zooming process to further adjust the light path and achieve a high magnification ratio. At the same time, the movement of the second zoom lens group G3 will not occupy too much of the total length of the lens, thereby helping to reduce the size of the lens.

[0149] The maximum movable distance D4 of the focus lens group G4 and the total optical length TTL of the zoom lens satisfy 0.058≤D4 / TTL≤0.096, ensuring that the focus lens group G4 can move effectively during the focusing process to achieve fast and accurate focusing. At the same time, the movement of the focus lens group G4 does not occupy too much of the total length of the lens, thereby helping to reduce the size of the lens.

[0150] Among them, by reasonably setting the maximum movable distance of the first zoom lens group G2 and the second zoom lens group G3, the rapid response of the zoom lens during the zooming process can be ensured, so that the zoom lens can quickly adjust the focal length during the zooming process and achieve rapid switching from wide angle to telephoto.

[0151] At the same time, by reasonably setting the maximum movable distance of the focus lens group G4, the rapid response of the zoom lens during the focusing process can be ensured, so that the zoom lens can quickly adjust the focus during the focusing process, thereby achieving fast and accurate focusing.

[0152] In summary, in this embodiment, by limiting the maximum movable distances of the first zoom lens group G2, the second zoom lens group G3 and the focus lens group G4, the zoom lens can achieve a fast response zoom-focus function, ensuring that rapid adjustment can be achieved during the zooming and focusing process. At the same time, the zoom lens can be made more compact and the total volume of the zoom lens can be reduced.

[0153] As a feasible implementation, the image plane size of the zoom lens is HI, and the total optical length of the zoom lens is TTL; wherein, 0.045≤HI / TTL≤0.106.

[0154] The image plane size can be understood as the image plane diagonal length or the image plane diameter.

[0155] In this embodiment, the image plane size HI of the zoom lens and the total optical length TTL of the zoom lens are set to satisfy 0.045≤HI / TTL≤0.106, which can control the volume of the zoom lens to a greater extent and realize a miniaturized design. At the same time, the image plane size can also be enlarged, thereby achieving the effect of compressing the volume and expanding the target surface.

[0156] Specific embodiments of the zoom lens applicable to the above-mentioned embodiments will be further described below with reference to the accompanying drawings.

[0157] Embodiment 1

[0158] like Figure 1 and Figure 2 As shown, the zoom lens provided by the first embodiment of the present invention includes a first fixed lens group G1, a first zoom lens group G2, a second zoom lens group G3, a focus lens group G4 and a second fixed lens group G5 which are arranged in sequence from the object plane to the image plane along the optical axis.

[0159] The first fixed lens group G1 includes a first lens L1, a second lens L2, a third lens L3 and a fourth lens L4 arranged in sequence from the object plane to the image plane. The first zoom lens group G2 includes a fifth lens L5, a sixth lens L6 and a seventh lens L7 arranged in sequence from the object plane to the image plane. The second zoom lens group G3 includes an eighth lens L8, a ninth lens L9, a tenth lens L10 and an eleventh lens L11 arranged in sequence from the object plane to the image plane. The focus lens group G4 includes a twelfth lens L12 and a thirteenth lens L13 arranged in sequence from the object plane to the image plane. The second fixed lens group G5 includes a fourteenth lens L14.

[0160] The first lens L1 and the second lens L2 form a first cemented lens group g1; the ninth lens L9 and the tenth lens L10 form a second cemented lens group g2.

[0161] The aperture STO is located in the optical path between the seventh lens L7 and the eighth lens L8, and the filter P is located on the image side of the fourteenth lens L14.

[0162] 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.

[0163] Table 1 Design values ​​of optical physical parameters of zoom lens

[0164]

[0165] The surface numbers in Table 1 are numbered according to the order of the surfaces of each lens, where "1" represents the object side of the first lens, "2" represents the image side of the first lens, and so on; "STO" represents the aperture of the zoom lens; the radius of curvature represents the degree of curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side, "INF" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface; the refractive index (Nd) represents the ability of the material between the current surface and the next surface to deflect light, and a blank space represents that the current position is air and the refractive index is 1; the Abbe number (Vd) represents the dispersion characteristics of the material between the current surface and the next surface to the light, and a blank space represents that the current position is air; the semi-aperture represents the corresponding half-height of the light on the surface of each lens, and "IMA" represents the image surface of the zoom lens.

[0166] Table 2 shows the values ​​of zoom intervals of the zoom lens in Table 1 at the wide-angle end and the telephoto end.

[0167] Table 2 Design values ​​of zoom intervals of zoom lenses

[0168]

[0169] The zoom intervals in Table 2 are different interval values ​​of the zoom lens at the wide-angle end and the telephoto end.

[0170] In this embodiment, the aspheric cone coefficient of the aspheric lens in the zoom lens can be defined by the following aspheric formula, but is not limited to the following expression method:

[0171] ;

[0172] Among them, z is the axial vector height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the inverse of the radius of curvature; k is the fitted cone coefficient; AI is the coefficient of the 4th, 6th, 8th, 10th, 12th, 14th, 16th, 18th, and 20th order terms of the aspheric polynomial.

[0173] Exemplarily, Table 3 describes in detail the aspheric cone coefficients of each lens in the first embodiment in a feasible implementation manner.

[0174] Table 3 Design values ​​of aspheric cone coefficients of each lens in the zoom lens

[0175]

[0176] The K value in Table 3 represents the numerical value of the best fitting cone coefficient of the aspheric surface.

[0177] The zoom lens of the first embodiment can achieve the following technical indicators:

[0178] Table 4 Technical specifications of zoom lenses

[0179]

[0180] Figure 7 This is a field curvature distortion diagram of the zoom lens provided in Embodiment 1 of the present invention at the wide-angle end. Figure 8 This is a field curvature distortion diagram of the zoom lens provided in the first embodiment of the present invention at the telephoto end. In the left coordinate system of the figure, the horizontal coordinate represents the magnitude of the field curvature, in units of mm; the vertical coordinate represents the normalized image height, without units. In the right coordinate system of the figure, the horizontal coordinate represents the magnitude of the distortion (F-Tan (Theta)), in units of %; the vertical coordinate represents the normalized image height, without units. Figure 7 and Figure 8It can be seen that the field curvature of the zoom lens provided in this embodiment at the wide-angle end and the telephoto end is effectively controlled, that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small. At the same time, the distortion of the zoom lens at the wide-angle end and the telephoto end is within the range of ±10%. Therefore, the distortion of the zoom lens provided in this embodiment at the wide-angle end and the telephoto end is well corrected, and the imaging distortion is small.

[0181] Figure 9-14 This is a light fan diagram of the zoom lens provided in the first embodiment of the present invention at different field angles at the wide-angle end. Figure 15-Figure 20 The light fan diagram of the zoom lens at different field angles at the telephoto end provided in Example 1 of the present invention, wherein the light fan diagram is one of the most commonly used evaluation methods in modern optical design. In the figure, the horizontal axis is the beam aperture, and the vertical axis is the vertical axis aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all light rays converge at the same point on the image plane, and the corresponding interval on the vertical axis of the curve is the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberrations of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. By Figure 9-Figure 20 It can be seen that each wavelength of the zoom lens in each field of view is well close to the horizontal axis, indicating that the vertical axis aberration of each wavelength is well corrected. At the same time, the curves of each wavelength do not have obvious dispersion, indicating that the chromatic aberration of the zoom lens at the wide-angle end and the telephoto end is also well corrected, thereby ensuring that the zoom lens can meet the high-resolution imaging requirements.

[0182] Fig.21 The vertical axis chromatic aberration diagram of the zoom lens provided in the first embodiment of the present invention at the wide-angle end is shown in FIG. Fig. 22 This is a vertical axis chromatic aberration diagram of the zoom lens provided in Embodiment 1 of the present invention at the telephoto end, wherein the vertical direction represents the normalization of the field of view, and 0 represents the optical axis; the main wavelength uses 546nm, and the horizontal direction represents the offset relative to the main wavelength, in micrometers (μm). Fig.21 and Fig. 22 The maximum field of view is 4.65 mm. Fig.21 and Fig. 22 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within a good range, indicating that the vertical chromatic aberration of the zoom lens at the wide-angle end and the telephoto end is well controlled and can meet the needs of wide-spectrum applications.

[0183] Embodiment 2

[0184] like Figure 3 and Figure 4 As shown, the zoom lens provided by the second embodiment of the present invention includes a first fixed lens group G1, a first variator group G2, a second variator group G3, a focus lens group G4 and a second fixed lens group G5 which are arranged in sequence from the object plane to the image plane along the optical axis.

[0185] The first fixed lens group G1 includes a first lens L1, a second lens L2, a third lens L3 and a fourth lens L4 arranged in sequence from the object plane to the image plane. The first zoom lens group G2 includes a fifth lens L5, a sixth lens L6 and a seventh lens L7 arranged in sequence from the object plane to the image plane. The second zoom lens group G3 includes an eighth lens L8, a ninth lens L9, a tenth lens L10 and an eleventh lens L11 arranged in sequence from the object plane to the image plane. The focus lens group G4 includes a twelfth lens L12 and a thirteenth lens L13 arranged in sequence from the object plane to the image plane. The second fixed lens group G5 includes a fourteenth lens L14.

[0186] The first lens L1 and the second lens L2 form a first cemented lens group g1; the ninth lens L9 and the tenth lens L10 form a second cemented lens group g2.

[0187] The aperture STO is located in the optical path between the seventh lens L7 and the eighth lens L8, and the filter P is located on the image side of the fourteenth lens L14.

[0188] 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 3 and Figure 4 Zoom lens shown.

[0189] Table 5 Design values ​​of optical physical parameters of zoom lens

[0190]

[0191] The surface numbers in Table 5 are numbered according to the order of the surfaces of each lens, where "1" represents the object side of the first lens, "2" represents the image side of the first lens, and so on; "STO" represents the aperture of the zoom lens; the radius of curvature represents the degree of curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side, "INF" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface; the refractive index (Nd) represents the ability of the material between the current surface and the next surface to deflect light, and a blank space represents that the current position is air and the refractive index is 1; the Abbe number (Vd) represents the dispersion characteristics of the material between the current surface and the next surface to the light, and a blank space represents that the current position is air; the semi-aperture represents the corresponding half-height of the light on the surface of each lens, and "IMA" represents the image surface of the zoom lens.

[0192] Table 6 shows the values ​​of the zoom intervals of the zoom lens in Table 5 at the wide-angle end and the telephoto end.

[0193] Table 6 Design values ​​of zoom intervals of zoom lenses

[0194]

[0195] The zoom intervals in Table 6 are different interval values ​​of the zoom lens at the wide-angle end and the telephoto end.

[0196] In this embodiment, the aspheric cone coefficient of the aspheric lens in the zoom lens can be defined by the following aspheric formula, but is not limited to the following expression method:

[0197] ;

[0198] Among them, z is the axial vector height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the inverse of the radius of curvature; k is the fitted cone coefficient; AI is the coefficient of the 4th, 6th, 8th, 10th, 12th, 14th, 16th, 18th, and 20th order terms of the aspheric polynomial.

[0199] Exemplarily, Table 7 describes in detail the aspheric cone coefficient of each lens in the second embodiment in a feasible implementation manner.

[0200] Table 7 Design values ​​of aspheric cone coefficients of each lens in the zoom lens

[0201]

[0202] The K value in Table 7 represents the numerical value of the best fitting cone coefficient of the aspheric surface.

[0203] The zoom lens of the second embodiment can achieve the following technical indicators:

[0204] Table 8 Technical specifications of zoom lenses

[0205]

[0206] Fig.23 This is a field curvature distortion diagram of the zoom lens provided in the second embodiment of the present invention at the wide-angle end. Fig.24 This is a field curvature distortion diagram of the zoom lens provided in the second embodiment of the present invention at the telephoto end. In the left coordinate system of the figure, the horizontal coordinate represents the magnitude of the field curvature, in units of mm; the vertical coordinate represents the normalized image height, without units. In the right coordinate system of the figure, the horizontal coordinate represents the magnitude of the distortion (F-Tan (Theta)), in units of %; the vertical coordinate represents the normalized image height, without units. Fig.23 and Fig.24It can be seen that the field curvature of the zoom lens provided in this embodiment at the wide-angle end and the telephoto end is effectively controlled, that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small. At the same time, the distortion of the zoom lens at the wide-angle end and the telephoto end is within the range of ±10%. Therefore, the distortion of the zoom lens provided in this embodiment at the wide-angle end and the telephoto end is well corrected, and the imaging distortion is small.

[0207] Figure 25-Figure 30 This is a light fan diagram of the zoom lens provided in the second embodiment of the present invention at different field angles at the wide-angle end. Figure 31-Figure 36 The light fan diagram of the zoom lens at different field angles at the telephoto end provided in Example 2 of the present invention, wherein the light fan diagram is one of the most commonly used evaluation methods in modern optical design. In the diagram, the horizontal axis is the beam aperture, and the vertical axis is the vertical axis aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all light rays converge at the same point on the image plane, and the corresponding interval on the vertical axis of the curve is the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberrations of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. By Figure 25-Figure 36 It can be seen that each wavelength of the zoom lens in each field of view is well close to the horizontal axis, indicating that the vertical axis aberration of each wavelength is well corrected. At the same time, the curves of each wavelength do not have obvious dispersion, indicating that the chromatic aberration of the zoom lens at the wide-angle end and the telephoto end is also well corrected, thereby ensuring that the zoom lens can meet the high-resolution imaging requirements.

[0208] Fig.37 The vertical axis chromatic aberration diagram of the zoom lens provided in the second embodiment of the present invention at the wide-angle end is shown in FIG. Fig.38 This is a vertical axis chromatic aberration diagram of the zoom lens provided in the second embodiment of the present invention at the telephoto end, wherein the vertical direction represents the normalization of the field of view, and 0 represents the optical axis; the main wavelength uses 546nm, and the horizontal direction represents the offset relative to the main wavelength, in micrometers (μm). Fig.37 and Fig.38 The maximum field of view is 4.60 mm. Fig.37 and Fig.38 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within a good range, indicating that the vertical chromatic aberration of the zoom lens at the wide-angle end and the telephoto end is well controlled and can meet the needs of wide-spectrum applications.

[0209] Embodiment 3

[0210] like Figure 5 and Figure 6 As shown, the zoom lens provided by the third embodiment of the present invention includes a first fixed lens group G1, a first variator group G2, a second variator group G3, a focus lens group G4 and a second fixed lens group G5 which are arranged in sequence from the object plane to the image plane along the optical axis.

[0211] The first fixed lens group G1 includes a first lens L1, a second lens L2, a third lens L3 and a fourth lens L4 arranged in sequence from the object plane to the image plane. The first zoom lens group G2 includes a fifth lens L5, a sixth lens L6 and a seventh lens L7 arranged in sequence from the object plane to the image plane. The second zoom lens group G3 includes an eighth lens L8, a ninth lens L9, a tenth lens L10 and an eleventh lens L11 arranged in sequence from the object plane to the image plane. The focus lens group G4 includes a twelfth lens L12 and a thirteenth lens L13 arranged in sequence from the object plane to the image plane. The second fixed lens group G5 includes a fourteenth lens L14.

[0212] The first lens L1 and the second lens L2 form a first cemented lens group g1; the ninth lens L9 and the tenth lens L10 form a second cemented lens group g2.

[0213] The aperture STO is located in the optical path between the seventh lens L7 and the eighth lens L8, and the filter P is located on the image side of the fourteenth lens L14.

[0214] 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 5 and Figure 6 Zoom lens shown.

[0215] Table 9 Design values ​​of optical physical parameters of zoom lens

[0216]

[0217] The surface numbers in Table 9 are numbered according to the order of the surfaces of each lens, where "1" represents the object side of the first lens, "2" represents the image side of the first lens, and so on; "STO" represents the aperture of the zoom lens; the radius of curvature represents the degree of curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side, "INF" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface; the refractive index (Nd) represents the ability of the material between the current surface and the next surface to deflect light, and a blank space represents that the current position is air and the refractive index is 1; the Abbe number (Vd) represents the dispersion characteristics of the material between the current surface and the next surface to the light, and a blank space represents that the current position is air; the semi-aperture represents the corresponding half-height of the light on the surface of each lens, and "IMA" represents the image surface of the zoom lens.

[0218] Table 10 shows the values ​​of the zoom intervals of the zoom lens in Table 9 at the wide-angle end and the telephoto end.

[0219] Table 10 Design values ​​of zoom intervals of zoom lenses

[0220]

[0221] The zoom intervals in Table 10 are different interval values ​​of the zoom lens at the wide-angle end and the telephoto end.

[0222] In this embodiment, the aspheric cone coefficient of the aspheric lens in the zoom lens can be defined by the following aspheric formula, but is not limited to the following expression method:

[0223] ;

[0224] Among them, z is the axial vector height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the inverse of the radius of curvature; k is the fitted cone coefficient; AI is the coefficient of the 4th, 6th, 8th, 10th, 12th, 14th, 16th, 18th, and 20th order terms of the aspheric polynomial.

[0225] Exemplarily, Table 11 describes in detail the aspheric cone coefficients of each lens in the third embodiment in a feasible implementation manner.

[0226] Table 11 Design values ​​of aspheric cone coefficients of each lens in the zoom lens

[0227]

[0228] The K value in Table 11 represents the numerical value of the best fitting cone coefficient of the aspheric surface.

[0229] The zoom lens of the third embodiment can achieve the following technical indicators:

[0230] Table 12 Technical specifications of zoom lenses

[0231]

[0232] Fig.39 This is a field curvature distortion diagram of the zoom lens provided in Embodiment 3 of the present invention at the wide-angle end. Fig.40 This is a field curvature distortion diagram of the zoom lens provided in the third embodiment of the present invention at the telephoto end. In the left coordinate system of the figure, the horizontal coordinate represents the magnitude of the field curvature, in units of mm; the vertical coordinate represents the normalized image height, without units. In the right coordinate system of the figure, the horizontal coordinate represents the magnitude of the distortion (F-Tan (Theta)), in units of %; the vertical coordinate represents the normalized image height, without units. Fig.39 and Fig.40It can be seen that the field curvature of the zoom lens provided in this embodiment at the wide-angle end and the telephoto end is effectively controlled, that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small. At the same time, the distortion of the zoom lens at the wide-angle end and the telephoto end is within the range of ±10%. Therefore, the distortion of the zoom lens provided in this embodiment at the wide-angle end and the telephoto end is well corrected, and the imaging distortion is small.

[0233] Figure 41-46 This is a light fan diagram of the zoom lens provided in the third embodiment of the present invention at different field angles at the wide-angle end. Figure 47-Figure 52 The light fan diagram of the zoom lens at different field angles at the telephoto end provided in Example 3 of the present invention, wherein the light fan diagram is one of the most commonly used evaluation methods in modern optical design. In the diagram, the horizontal axis is the beam aperture, and the vertical axis is the vertical axis aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all light rays converge at the same point on the image plane, and the corresponding interval on the vertical axis of the curve is the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberrations of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. By Figure 41-Figure 52 It can be seen that each wavelength of the zoom lens in each field of view is well close to the horizontal axis, indicating that the vertical axis aberration of each wavelength is well corrected. At the same time, the curves of each wavelength do not have obvious dispersion, indicating that the chromatic aberration of the zoom lens at the wide-angle end and the telephoto end is also well corrected, thereby ensuring that the zoom lens can meet the high-resolution imaging requirements.

[0234] Fig.53 This is a vertical axis chromatic aberration diagram of the zoom lens provided in the third embodiment of the present invention at the wide-angle end, Fig.54 This is a vertical axis chromatic aberration diagram of the zoom lens provided in Embodiment 3 of the present invention at the telephoto end, wherein the vertical direction represents the normalization of the field of view, and 0 represents the optical axis; the main wavelength uses 546nm, and the horizontal direction represents the offset relative to the main wavelength, in micrometers (μm). Fig.53 and Fig.54 The maximum field of view is 4.60 mm. Fig.53 and Fig.54 It can be seen that the vertical chromatic aberration of different wavelengths is controlled within a good range, indicating that the vertical chromatic aberration of the zoom lens at the wide-angle end and the telephoto end is well controlled and can meet the needs of wide-spectrum applications.

[0235] In order to explain the above embodiments more clearly, Table 13 details the specific optical and physical parameters of each lens in the zoom lens provided in Embodiments 1 to 3 of the present invention.

[0236] Table 13 Design values ​​of optical physical parameters of zoom lens

[0237]

[0238] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A zoom lens, characterized in that: The zoom lens comprises a first fixed lens group, a first zoom lens group, a second zoom lens group, a focus lens group and a second fixed lens group, which are arranged in sequence from the object plane to the image plane along the optical axis, and the number of lens groups with optical power in the zoom lens is five; The first fixed lens group and the second fixed lens group are fixedly arranged, and the first variable magnification lens group, the second variable magnification lens group and the focus lens group are movably arranged along the optical axis direction; The first fixed lens group has positive optical power, the first zoom lens group has negative optical power, the second zoom lens group has positive optical power, the focus lens group has positive optical power, and the second fixed lens group has negative optical power; The first fixed lens group is composed of a first lens, a second lens, a third lens and a fourth lens arranged in sequence from the object plane to the image plane; the first lens has a negative optical power, the second lens has a positive optical power, the third lens has a positive optical power, and the fourth lens has a positive optical power; The first zoom lens group is composed of a fifth lens, a sixth lens and a seventh lens arranged in sequence from the object plane to the image plane; the fifth lens has a negative optical power, the sixth lens has a negative optical power, and the seventh lens has a positive optical power; The second zoom lens group is composed of an eighth lens, a ninth lens, a tenth lens and an eleventh lens arranged in sequence from the object plane to the image plane; the eighth lens has a positive optical power, the ninth lens has a positive optical power, the tenth lens has a negative optical power, and the eleventh lens has a positive optical power; The focusing lens group is composed of a twelfth lens and a thirteenth lens arranged in sequence from the object plane to the image plane; the twelfth lens has a positive optical power, and the thirteenth lens has a negative optical power; The second fixed lens group is composed of a fourteenth lens; the fourteenth lens has a negative optical power; The focal length of the first fixed lens group is FG1, the focal length of the first variator group is FG2, the focal length of the second variator group is FG3, the focal length of the focus lens group is FG4, the focal length of the second fixed lens group is FG5, and the focal length of the zoom lens at the wide-angle end is FW; 5.365≤FG1 / FW≤6.339; -1.289≤FG2 / FW≤-0.878; 2.949≤FG3 / FW≤3.769; 2.405≤FG4 / FW≤2.897; -14.214≤FG5 / FW≤-6.

978.

2. The zoom lens according to claim 1, wherein: The first lens and the second lens form a first cemented lens group; The ninth lens and the tenth lens form a second cemented lens group.

3. The zoom lens according to claim 1, wherein: The first lens and the second lens form a first cemented lens group; The focal length of the first lens is F1, the focal length of the first cemented lens group is F101, 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; -0.536≤F1 / F101≤0.478; 23.654mm≤|F101 / (FT / FW)|≤34.249mm.

4. 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; 6.354mm≤(FT-FW) / (FT / FW)≤7.421mm.

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

6. The zoom lens according to claim 5, characterized in that: The refractive index of the sixth lens is Nd1, and the Abbe number is Vd1; the refractive index of the eleventh lens is Nd2, and the Abbe number is Vd2; the refractive index of the twelfth lens is Nd3, and the Abbe number is Vd3; the refractive index of the fourteenth lens is Nd4, and the Abbe number is Vd4; 1.45≤Nd1≤1.51; 20.00≤Vd1≤95.00; 1.45≤Nd2≤1.51; 20.00≤Vd2≤95.00; 1.45≤Nd3≤1.50; 20.00≤Vd3≤95.00; 1.54≤Nd4≤1.66;20.00≤Vd4≤95.

00.

7. 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; the optical distortion of the zoom lens at the wide-angle end is DIS1, and the optical distortion of the zoom lens at the telephoto end is DIS2; 14.600≤FT / FW≤19.954; 2.428≤|FW / DIS1|≤4.189; 26.667≤|FT / DIS2|≤55.

922.

8. The zoom lens according to claim 1, wherein: The maximum movable distance of the first variator group is D2, the maximum movable distance of the second variator group is D3, the maximum movable distance of the focus lens group is D4, and the total optical length of the zoom lens is TTL; 0.245≤D2 / TTL≤0.376; 0.068≤D3 / TTL≤0.087; 0.058≤D4 / TTL≤0.

096.

9. The zoom lens according to claim 1, wherein: The image plane size of the zoom lens is HI, and the total optical length of the zoom lens is TTL; 0.045≤HI / TTL≤0.106.

Images