Zoom lens

Abstract

The utility model discloses a zoom lens, which comprises a first fixed lens group, a zoom lens group, a diaphragm, a second fixed lens group, a focusing lens group and a third fixed lens group which are sequentially arranged from an object plane to an image plane along an optical axis, and the focal powers are respectively positive, negative, positive, negative and positive; the first fixed lens group consists of three lenses, and the focal powers of the three lenses are respectively negative, positive and positive; the zoom lens group is composed of four lenses, and the focal power of the four lenses is negative, negative, positive and negative. The second fixed lens group consists of four lenses, and the focal powers of the four lenses are respectively positive, positive, negative and positive; the focusing lens group is composed of a lens, and the focal power is negative. The third fixed lens group consists of four lenses, and the focal powers of the four lenses are respectively positive, negative, positive and negative; the seventh lens, the eighth lens and the thirteenth lens are aspheric lenses. The zoom lens can meet the use requirements of small distortion, large aperture and clear imaging on a 1 / 1.2 ''target surface and at the wave band of 405nm-656nm.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of optical devices, and particularly to a zoom lens. Background Art

[0002] The ITS (Intelligent Traffic System) lens is a lens specially designed for an image sensor. Among them, most of the commonly used ITS lenses on the market at present are fixed-focus lenses, and have low imaging quality and poor tolerance in harsh environments; in the face of a more complex use environment, zoom lenses have gradually become the new favorites in the ITS field. However, the types of zoom lenses for the ITS field on the market are extremely limited, and there are problems such as low image quality, too small focal length range, and small temperature application range, which are difficult in actual applications. Therefore, it is particularly necessary to develop a zoom lens with a large aperture, high definition, wide temperature application range, and long focal length to meet the ITS requirements. Summary of the Utility Model

[0003] The present application provides a zoom lens, which can meet the usage requirements of small distortion, large aperture, and clear imaging on a 1 / 1.2″ target surface and in the wavelength range of 405 nm - 656 nm.

[0004] The embodiments of the present application provide a zoom lens, which includes a first fixed lens group with positive optical power, a variable magnification lens group with negative optical power, a diaphragm, a second fixed lens group with positive optical power, a focusing lens group with negative optical power, and a third fixed lens group with positive optical power, which are arranged in sequence along the optical axis from the object plane to the image plane; the first fixed lens group and the second fixed lens group are fixed, and the variable magnification lens group and the focusing lens group move along the optical axis direction during zooming;

[0005] Along the optical axis from the object plane to the image plane direction:

[0006] The first fixed 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;

[0007] The variable magnification lens group includes a fourth lens with negative optical power, a fifth lens with negative optical power, a sixth lens with positive optical power, and a seventh lens with negative optical power; the seventh lens is an aspherical lens;

[0008] The second fixed lens group includes an eighth lens with positive optical power, a ninth lens with positive optical power, a tenth lens with negative optical power, and an eleventh lens with positive optical power; the eighth lens is an aspherical lens;

[0009] The focusing lens group includes a twelfth lens with negative optical power;

[0010] The third fixed lens group includes a thirteenth lens with a positive optical power, a fourteenth lens with a negative optical power, a fifteenth lens with a positive optical power, and a sixteenth lens with a negative optical power; the thirteenth lens is an aspherical lens;

[0011] For the zoom lens, the position of the aperture relative to the image plane remains the same at different focal lengths, and the aperture diameter is the same at different focal lengths. At the same time, it satisfies: F / EPD ≤ 1.50;

[0012] Wherein, F is the focal length of the zoom lens, and EPD is the entrance pupil diameter of the zoom lens in the state of focal length F.

[0013] Optionally, along the direction of the optical axis from the object side to the image side, the surface of the lens close to the object surface is the object side surface, and the surface of the lens close to the image surface is the image side surface;

[0014] In the first fixed lens group, the surface type of the first lens is convex-concave; the surface type of the second lens is convex-convex; the surface type of the third lens is convex-concave or convex-flat;

[0015] In the varifocal lens group, the image side surface of the fourth lens is concave, the surface type of the fifth lens is concave-concave, the object side surface of the sixth lens is convex, and the object side surface of the seventh lens is concave;

[0016] In the second fixed lens group, the surface type of the eighth lens is convex-concave, the surface type of the ninth lens is convex-convex, the surface type of the tenth lens is convex-concave; the surface type of the eleventh lens is convex-convex;

[0017] In the focusing lens group, the surface type of the twelfth lens is convex-concave;

[0018] In the third fixed lens group, the image side surface of the thirteenth lens is convex at the center, the image side surface of the fourteenth lens is concave; the image side surface of the fifteenth lens is convex-convex, and the surface type of the sixteenth lens is concave-concave.

[0019] Optionally, 5.44 ≤ F1 / FW ≤ 5.49; -1.70 ≤ F2 / FW ≤ -1.68;

[0020] 1.78 ≤ F3 / FW ≤ 1.89; -8.64 ≤ F4 / FW ≤ -6.45; 3.62 ≤ F5 / FW ≤ 6.55;

[0021] Wherein, F1, F2, F3, F4, and F5 are the focal lengths of the first fixed lens group, the varifocal lens group, the second fixed lens group, the focusing lens group, and the third fixed lens group respectively; FW is the focal length of the wide-angle end of the zoom lens.

[0022] Optionally, 5.30 ≤ S2 / S4 ≤ 6.22; 0.43 ≤ S4 / TTL ≤ 0.52;

[0023] wherein, S2 is the maximum distance that the variable magnification lens group moves along the optical axis, S4 is the maximum distance that the focusing lens group moves along the optical axis; TTL represents the total length of the zoom lens.

[0024] Optionally, Vd7 ≥ 63.9; Vd8 ≥ 63.9;

[0025] wherein, Vd7 is the Abbe number of the seventh lens, and Vd8 is the Abbe number of the eighth lens.

[0026] Optionally, -25.44 ≤ F8 / F3 ≤ -25.24;

[0027] wherein, F8 represents the focal length of the eighth lens, and F3 represents the focal length of the second fixed lens group.

[0028] Optionally, the first lens and the second lens are combined into a doublet lens group.

[0029] Optionally, the fifth lens and the sixth lens of the variable magnification lens group are combined into a doublet lens group.

[0030] Optionally, the tenth lens and the eleventh lens of the second fixed lens group are combined into a doublet lens group.

[0031] Optionally, the thirteenth lens and the fourteenth lens of the third fixed lens group are combined into a doublet lens group.

[0032] The zoom lens provided by the embodiment of the present application includes a first fixed lens group, a variable magnification lens group, a diaphragm, a second fixed lens group, a focusing lens group, and a third fixed lens group arranged in sequence along the optical axis from the object plane to the image plane, and the optical powers are positive, negative, positive, negative, and positive respectively; the first fixed lens group is composed of three lenses, and the optical powers are negative, positive, and positive respectively; the variable magnification lens group is composed of four lenses, and the optical powers are negative, negative, positive, and negative respectively; the second fixed lens group is composed of four lenses, and the optical powers are positive, positive, negative, and positive respectively; the focusing lens group is composed of one lens, and the optical power is negative; the third fixed lens group is composed of four lenses, and the optical powers are positive, negative, positive, and negative respectively; the seventh lens, the eighth lens, and the thirteenth lens are aspherical lenses. This zoom lens can meet the usage requirements of small distortion, large aperture, and clear imaging on a 1 / 1.2" target surface and in the 405nm - 656nm wavelength band. Brief Description of the Drawings

[0033] Figure 1 It is a schematic structural diagram of the zoom lens provided by Embodiment 1 of the present application at the wide-angle end;

[0034] Figure 2 Schematic diagram of the structure of the zoom lens provided in the first embodiment of the present application at the telephoto end;

[0035] Figure 3 Light fan diagram of the zoom lens provided in the first embodiment of the present application at the wide-angle end;

[0036] Figure 4 Field curvature and distortion diagram of the zoom lens provided in the first embodiment of the present application at the wide-angle end;

[0037] Figure 5 Axial aberration curve of the zoom lens provided in the first embodiment of the present application at the wide-angle end;

[0038] Figure 6 Light fan diagram of the zoom lens provided in the first embodiment of the present application at the telephoto end;

[0039] Figure 7 Field curvature and distortion diagram of the zoom lens provided in the first embodiment of the present application at the telephoto end;

[0040] Figure 8 Axial aberration curve of the zoom lens provided in the first embodiment of the present application at the telephoto end;

[0041] Figure 9 Schematic diagram of the structure of the zoom lens provided in the second embodiment of the present application at the wide-angle end;

[0042] Figure 10 Schematic diagram of the structure of the zoom lens provided in the second embodiment of the present application at the telephoto end;

[0043] Figure 11 Light fan diagram of the zoom lens provided in the second embodiment of the present application at the wide-angle end;

[0044] Figure 12 Field curvature and distortion diagram of the zoom lens provided in the second embodiment of the present application at the wide-angle end;

[0045] Figure 13 Axial aberration curve of the zoom lens provided in the second embodiment of the present application at the wide-angle end;

[0046] Figure 14 Light fan diagram of the zoom lens provided in the second embodiment of the present application at the telephoto end;

[0047] Figure 15 Field curvature and distortion diagram of the zoom lens provided in the second embodiment of the present application at the telephoto end;

[0048] Figure 16 Axial aberration curve of the zoom lens provided in the second embodiment of the present application at the telephoto end;

[0049] Figure 17 Schematic diagram of the structure of the zoom lens provided in the third embodiment of the present application at the wide-angle end;

[0050] Figure 18 Schematic diagram of the structure of the zoom lens provided in the third embodiment of the present application at the telephoto end;

[0051] Figure 19 Ray fan diagram of the zoom lens provided in the third embodiment of the present application at the wide-angle end;

[0052] Figure 20 Field curvature and distortion diagram of the zoom lens provided in the third embodiment of the present application at the wide-angle end;

[0053] Figure 21 Axial aberration curve of the zoom lens provided in the third embodiment of the present application at the wide-angle end;

[0054] Figure 22 Ray fan diagram of the zoom lens provided in the third embodiment of the present application at the telephoto end;

[0055] Figure 23 Field curvature and distortion diagram of the zoom lens provided in the third embodiment of the present application at the telephoto end;

[0056] Figure 24 Axial aberration curve of the zoom lens provided in the third embodiment of the present application at the telephoto end. Detailed implementation manners

[0057] The present application will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present application, rather than limiting the present application. In addition, it should be noted that for the sake of description, only parts related to the present invention are shown in the drawings, rather than all the structures.

[0058] Figure 1 Schematic diagram of the structure of the zoom lens provided in the first embodiment of the present application at the wide-angle end, Figure 2 Schematic diagram of the structure of the zoom lens provided in the first embodiment of the present application at the telephoto end. Refer to Figure 1 and Figure 2 , a zoom lens provided in an embodiment of the present application includes a first fixed lens group G1 with a positive optical power, a variable magnification lens group G2 with a negative optical power, a stop STO, a second fixed lens group G3 with a positive optical power, a focusing lens group G4 with a negative optical power, and a third fixed lens group G5 with a positive optical power, which are arranged in sequence along the optical axis from the object plane to the image plane; the first fixed lens group G1 and the second fixed lens group G3 are fixed, and the variable magnification lens group G2 and the focusing lens group move along the optical axis direction during zooming.

[0059] Along the optical axis from the object plane to the image plane direction:

[0060] The first fixed lens group G1 includes a first lens L1 with a negative focal power, a second lens L2 with a positive focal power, and a third lens L3 with a positive focal power.

[0061] The variable magnification lens group G2 includes a fourth lens L4 with a negative focal power, a fifth lens L5 with a negative focal power, a sixth lens L6 with a positive focal power, and a seventh lens L7 with a negative focal power; the seventh lens L7 is an aspherical lens.

[0062] The second fixed lens group G3 includes an eighth lens L8 with a positive focal power, a ninth lens L9 with a positive focal power, a tenth lens L10 with a negative focal power, and an eleventh lens L11 with a positive focal power; the eighth lens L8 is an aspherical lens.

[0063] The focusing lens group G4 includes a twelfth lens L12 with a negative focal power.

[0064] The third fixed lens group G5 includes a thirteenth lens L13 with a positive focal power, a fourteenth lens L14 with a negative focal power, a fifteenth lens L15 with a positive focal power, and a sixteenth lens L16 with a negative focal power; the thirteenth lens L13 is an aspherical lens.

[0065] In the zoom lens, the position of the diaphragm relative to the image plane remains consistent at different focal lengths, and the aperture of the diaphragm is the same at different focal lengths, and at the same time satisfies: F / EPD ≤ 1.50.

[0066] Wherein, F is the focal length of the zoom lens, and EPD is the entrance pupil diameter of the zoom lens in the state of focal length F.

[0067] Specifically, referring to Figure 1 and Figure 2 , in the zoom lens provided in the embodiment of the present application, the first fixed lens group G1, the variable magnification lens group G2, the second fixed lens group G3, the focusing lens group G4, and the third fixed lens group G5 can be arranged in a lens barrel ( Figure 1 and Figure 2Inside (not shown in the figure). The first fixed lens group G1, the second fixed lens group G3, and the third fixed lens group G5 are fixed in position in the lens barrel. At this time, the first fixed lens group G1, the second fixed lens group G3, and the third fixed lens group G5 are stationary relative to the image plane IMA. The variable magnification lens group G2 and the focusing lens group G4 can reciprocate along the optical axis direction in the lens barrel. Moving the variable magnification lens group G2 can achieve variable magnification, and moving the focusing lens group G4 focuses the imaging. On the one hand, it can compensate for the aberration caused during the zoom movement of the variable magnification lens group G2, effectively achieving aberration balance at each focal length. On the other hand, it adjusts the distance between the lens and the object or the imaging plane to ensure clear imaging of the object at different focal lengths. Through the common movement of the variable magnification lens group G2 and the focusing lens group G4, the focal length of the zoom lens can be continuously changed from wide-angle to telephoto.

[0068] It can be understood that during the zooming process of the zoom lens by moving the variable magnification lens group G2 and the focusing lens group G4, when the focal length is the shortest, the zoom lens is at the wide-angle end, and when the focal length is the longest, the zoom lens is at the telephoto end. At the wide-angle end and the telephoto end, the zoom lens has different focal lengths and optical powers, and also has different shapes.

[0069] It should be noted that Figure 1 , Figure 2 and the corresponding structural schematic diagrams of subsequent embodiments are only for structural illustration, and shapes such as aspheres are not shown according to the actual situation.

[0070] Furthermore, the optical power is equal to the difference between the image-side beam convergence and the object-side beam convergence, and its value is the reciprocal of the focal length. It characterizes the ability of the zoom lens to deflect light rays. The larger the absolute value of the optical power, the stronger the bending ability of the light rays; the smaller the absolute value of the optical power, the weaker the bending ability of the light rays. When the optical power is positive, the refraction of the light rays is convergent; when the optical power is negative, the refraction of the light rays is divergent. The optical power can be applied to characterize a certain refracting surface of a lens (i.e., a surface of the lens), can be applied to characterize a certain lens, and can also be applied to characterize a system formed by multiple lenses together (i.e., a lens group).

[0071] Among them, along the direction of the optical axis from the object plane to the image plane, the surface of the lens adjacent to the object plane is the object side surface, and the surface of the lens adjacent to the image plane is the image side surface.

[0072] In the first fixed lens group G1, the surface shape of the first lens L1 is convex-concave, the surface shape of the second lens L2 is convex-convex, and the surface shape of the third lens L3 is convex-concave or convex-flat.

[0073] In the variable magnification lens group G2, the image side surface of the fourth lens L4 is concave, the surface shape of the fifth lens L5 is concave-concave, the object side surface of the sixth lens L6 is convex, and the object side surface of the seventh lens L7 is concave.

[0074] In the second fixed lens group G3, the surface shape of the eighth lens L8 is convex-concave, the surface shape of the ninth lens L9 is convex-convex, the surface shape of the tenth lens L10 is convex-concave, and the surface shape of the eleventh lens L11 is convex-convex.

[0075] In the focusing lens group G4, the surface shape of the twelfth lens L12 is convex-concave.

[0076] In the third fixed lens group G5, the image side surface of the thirteenth lens L13 is convex at the center, the image side surface of the fourteenth lens L14 is concave, the image side surface of the fifteenth lens L15 is convex-convex, and the surface shape of the sixteenth lens L16 is concave-concave.

[0077] Among them, the concave lens has a diverging effect on the transmitted light, and the convex lens has a converging effect on the transmitted light. By reasonably setting the surface shapes of the first lens L1 to the sixteenth lens L16, clear imaging of the zoom lens at various focal lengths can be achieved.

[0078] The seventh lens L7, the eighth lens L8, and the thirteenth lens L13 are all aspherical lenses. When light passes through the aperture stop STO, the use of aspherical lenses can well correct aberration, avoid the situation where aberration is superimposed at the rear end of the lens, making it difficult to pull back the rear end, and can effectively improve the image quality.

[0079] In the embodiment of the present application, the aspherical lenses of the zoom lens satisfy the following formula:

[0080]

[0081] Among them, Z is the axial distance from the surface at a position perpendicular to the optical axis with a height of r along the optical axis direction to the vertex of this surface; c represents the curvature at the vertex of the aspherical surface; a4, a6, a8, a10, a12, a14 are the high-order aspherical coefficients of the fourth, sixth, eighth, tenth, twelfth, and fourteenth orders of the corresponding aspherical surfaces, a i r i Combined into the high-order terms of the corresponding aspherical surface, i = 4, 6, 8, 10, 12, 14.

[0082] Among them, the aperture stop STO includes an aperture diaphragm and a field stop. The aperture diaphragm refers to the diaphragm that limits the most light beams, and the field stop refers to the diaphragm that limits the most field of view (size).

[0083] Among them, the cost of the plastic lens is much lower than that of the glass lens. One or more of the seventh lens L7, the eighth lens L8, and the thirteenth lens L13 can adopt a plastic aspherical lens, which can greatly reduce the cost of the zoom lens; or, one of the seventh lens L7, the eighth lens L8, and the thirteenth lens L13 adopts a glass spherical lens, or a combination of a glass aspherical lens and a plastic aspherical lens. These two types of materials, glass and plastic, can also compensate for each other, balance high and low temperatures, and enable the zoom lens to have stable high and low temperature performance, which helps to improve the environmental adaptability of the zoom lens.

[0084] It should be noted that the materials of other lenses can be glass or plastic, which are not restricted here. The material of the plastic aspherical lens can be various plastics known to those skilled in the art, and the material of the glass spherical lens can be various types of glass known to those skilled in the art. The embodiments of the present application will not elaborate or limit this.

[0085] Referring to Figure 1 and Figure 2 , a first fixed lens group G1 with positive optical power and a variable magnification lens group G2 with negative optical power are used at the front end of the aperture STO, which can ensure that a larger light beam diameter is generated after the light passes through, increase the aperture number of the zoom lens, and meet the usage requirements under different conditions. A second fixed lens group G3 with positive optical power, a focusing lens group G4 with negative optical power, and a third fixed lens group G5 with positive optical power used at the rear end of the aperture STO can correct the aberration at the rear end of the lens, and cooperate with the lens group at the front end of the aperture STO to stabilize the imaging quality of the zoom lens.

[0086] Specifically, setting the aperture STO between the seventh lens L7 with negative optical power and the eighth lens L8 with positive optical power can adjust the propagation direction of the light beam emitted by the seventh lens L7 to the incident surface of the eighth lens L8, and then limit the light beam or the field of view range in the zoom lens, thereby improving the imaging quality of the zoom lens. In this way, by changing the positions of the variable magnification lens group G2 and the focusing lens group G4 on the optical axis, the zoom lens can be switched between the wide-angle end and the telephoto end at any time.

[0087] Furthermore, by controlling the aperture diameter of the aperture STO to be the same at different focal lengths, the aperture range can be reduced structurally, ensuring that the movable group of the lens has a longer moving distance, reducing the volume of the zoom lens, and simultaneously achieving a higher imaging magnification to meet the usage requirements under different conditions.

[0088] In the embodiment of the present application, by reasonably allocating the number of lenses of the first fixed lens group G1, the zoom lens group G2, the second fixed lens group G3, the focusing lens group G4, and the third fixed lens group G5, as well as the optical power of each lens, the optical powers of each lens group and each lens cooperate with each other to compensate for the aberration caused during the zoom movement of the zoom lens group G2, effectively achieving aberration balance in each focal segment and ensuring the clarity of the image at different focal lengths.

[0089] It should be noted that the materials of other lenses can be glass or plastic, which are not limited here. The material of the plastic aspherical lens can be various plastics known to those skilled in the art, and the material of the glass spherical lens can be various types of glass known to those skilled in the art. The embodiments of the present application do not elaborate or limit this.

[0090] Based on the above embodiments, referring to Figure 1 - Figure 2 , at least one cemented lens is included in the first fixed lens group G1. The first lens L1 and the second lens L2 can be combined into a doublet lens group or used as two single lenses. For example, when the first lens L1 and the second lens L2 are combined into a doublet lens group, it can effectively reduce the air gap between the first lens L1 and the second lens L2 and reduce the total length of the zoom lens. The doublet lens group formed by cementing the first lens L1 and the second lens L2 is of the convex-convex type. This cemented lens group is beneficial for the object-side light to enter the imaging system smoothly, can correct high-order aberrations to a great extent, and at the same time, this shape can better collect light with a large field of view angle, ensuring the imaging requirements of a wide-angle large field of view.

[0091] Among them, the cemented lens group in the embodiment of the present application can also be referred to as a cemented lens.

[0092] Based on the above embodiments, referring to Figure 1 - Figure 2 , at least one cemented lens is included in the zoom lens group G2. For example, the fifth lens L5 and the sixth lens L6 are combined into a doublet lens group.

[0093] Among them, the fifth lens L5 and the sixth lens L6 can be combined into a doublet lens group or used as two single lenses.

[0094] Specifically, by forming a cemented lens group composed of the fifth lens L5 and the sixth lens L6 in the varifocal lens group G2 into a front concave lens, the air gap between the fifth lens L5 and the sixth lens L6 can be effectively reduced, and the overall length of the zoom lens can be reduced. When light diverges through the fifth lens L5 with a negative optical power and then enters the sixth lens L6 with a positive optical power for convergence, then diverges through the seventh lens L7 with a negative optical power and enters the eighth lens L8 with a positive optical power in the eighth lens L8 with a positive optical power for convergence, the light can be diffusely and focusedly transmitted multiple times, enabling the light to pass through the middle of the lens smoothly. And before the light enters the second fixed lens group G3, using cemented lenses can reduce the chromatic aberration and spherical aberration generated at the front end, further improving the imaging quality.

[0095] Meanwhile, the combination of the cemented lens group composed of the first lens L1 and the second lens L2 used in the first fixed lens group G1 and the cemented lens group composed of the fifth lens L5 and the sixth lens L6 used in the varifocal lens group G2, the combined matching of the two cemented lens groups can also correct the high-order chromatic aberration and spherical aberration of the lens, control the aberration balance of each group, and avoid serious spherical aberration when light enters the second fixed lens group G3 behind the diaphragm STO, thereby improving the imaging quality of the zoom lens.

[0096] Based on the above embodiments, referring to Figure 1 - Figure 2 , the tenth lens L10 and the eleventh lens L11 of the second fixed lens group G3 are combined into a cemented lens group.

[0097] Among them, the tenth lens L10 and the eleventh lens L11 can be combined into a cemented lens group or used as two single lenses.

[0098] Specifically, the cemented lens group composed of the tenth lens L10 and the eleventh lens L11 in the second fixed lens group G3 is a convex-convex lens. After the light is continuously focused by the eighth lens L8 with a positive optical power and the ninth lens L9 with a positive optical power, it is diffused by the tenth lens L10 with a negative optical power and then converges through the eleventh lens L11 with a positive optical power, which is beneficial for the light to pass through the middle of the lens smoothly. Before entering the third fixed lens group G5 at the back end, using cemented lenses can reduce the air gap between the tenth lens L10 and the eleventh lens L11, reduce the overall length of the zoom lens, and at the same time reduce the chromatic aberration and spherical aberration generated at the front end, further improving the imaging quality.

[0099] Based on the above embodiments, referring to Figure 1 - Figure 2 , the thirteenth lens L13 and the fourteenth lens L14 in the third fixed lens group G5 are combined into a cemented lens group.

[0100] Among them, the thirteenth lens L13 and the fourteenth lens L14 can be combined into a cemented lens group or used as two single lenses.

[0101] Specifically, the thirteenth lens L13 and the fourteenth lens L14 can be combined into a doublet lens group, which is a convex-concave lens. After the light converges on the thirteenth lens L13 with a positive focal power, it diffuses through the fourteenth lens L14 with a negative focal power, and then converges through the fifteenth lens L15 with a positive focal power and diffuses through the sixteenth lens L16 with a negative focal power to form an image on the image plane IMA. The doublet lens group formed by combining the thirteenth lens L13 and the fourteenth lens L14 can correct the chromatic aberration and high-order aberrations generated in the focusing lens group G4, reduce the aberration pressure of other groups in the lens at different focal lengths before imaging, so as to achieve focusing of the zoom lens at the full focal range.

[0102] At the same time, the cemented setting can minimize or eliminate chromatic aberration to fully correct various aberrations of the zoom lens. On the premise of a compact structure, it can improve the resolution, optimize optical performance such as distortion, reduce the light loss caused by reflection between lenses, enhance the illuminance, thereby improving the image quality and enhancing the clarity of the lens imaging. In addition, the cemented lens group can also reduce the assembly components between lenses, simplify the assembly procedure in the lens manufacturing process, reduce costs, and reduce the tolerance sensitivity problems such as tilt / eccentricity generated during the assembly of the lens unit.

[0103] Based on the above embodiments, referring to Figure 1 - Figure 2 , the focal lengths of each lens group of the zoom lens and the focal length of the wide-angle end of the zoom lens satisfy the following relationship:

[0104] 5.44 ≤ F1 / FW ≤ 5.49; -1.70 ≤ F2 / FW ≤ -1.68;

[0105] 1.78 ≤ F3 / FW ≤ 1.89; -8.64 ≤ F4 / FW ≤ -6.45; 3.62 ≤ F5 / FW ≤ 6.55;

[0106] Among them, F1, F2, F3, F4, and F5 are the focal lengths of the first fixed lens group G1, the variable magnification lens group G2, the second fixed lens group G3, the focusing lens group G4, and the third fixed lens group G5 respectively; FW is the focal length of the wide-angle end of the zoom lens.

[0107] Specifically, adopting the above matching method for the focal lengths of each lens group and the focal length of the wide-angle end of the zoom lens is conducive to achieving a reasonable matching of the focal power, enabling the light to pass through the lens more smoothly, correcting the influence of high-order aberrations on the imaging quality to a great extent, expanding the field of view angle of the optical system, and expanding the usage range of the optical system.

[0108] Based on the above embodiments, referring to Figure 1 - Figure 2, the moving distances of the variable magnification lens group G2 and the focusing lens group G4 along the optical axis direction satisfy the following relationships: 5.30 ≤ S2 / S4 ≤ 6.22; 0.43 ≤ S4 / TTL ≤ 0.52.

[0109] Among them, S2 is the maximum moving distance of the variable magnification lens group G2 along the optical axis direction, S4 is the maximum moving distance of the focusing lens group G4 along the optical axis direction; TTL represents the total length of the zoom lens.

[0110] Specifically, by controlling the moving distances of the variable magnification lens group G2 and the focusing lens group G4, the volume of the focusing lens group G4 can be minimized to the greatest extent, the lens space can be compressed, and stable imaging can be achieved within a small moving range for the entire focal length range. At the same time, the overall volume of the zoom lens can be reduced to meet the requirements of lens miniaturization.

[0111] Based on the above embodiments, referring to Figure 1 - Figure 2 , the materials of the seventh lens L7 and the eighth lens L8 in the zoom lens meet the following requirements: Vd7 ≥ 63.9. Among them, Vd7 is the Abbe number of the seventh lens L7.

[0112] Specifically, the position of the variable magnification lens group G2 in the optical system is different at different focal lengths, and the aberration balance of the entire system is an important factor to ensure the imaging quality of the optical system. The seventh lens L7 uses an aspherical lens, which has a good correction effect on the high-order aberrations of the optical system. Cooperating with a material with a large Abbe number can synchronously correct the chromatic aberration within the group and balance the aberrations of the optical system across the entire focal length range.

[0113] Based on the above embodiments, referring to Figure 1 - Figure 2 , the material of the eighth lens L8 in the zoom lens meets the following requirements: Vd8 ≥ 63.9. Vd8 is the Abbe number of the eighth lens L8.

[0114] Specifically, if there are high-order aberrations and chromatic aberrations in the light rays entering the end of the optical system, it will seriously affect the actual imaging quality. In this application, the eighth lens L8 uses an aspherical lens and a material with a large Abbe number. Adding an aspherical lens directly after the aperture stop STO can more effectively control the high-order aberrations generated by the front-end light rays after passing through the aperture stop STO, and can weaken or even eliminate the aberrations to the greatest extent near the aperture stop STO. In this way, the eighth lens L8 cooperates with the seventh lens L7 (aspherical lens) at the front end to ensure the imaging quality of the optical system.

[0115] Based on the above embodiments, referring to Figure 1 - Figure 2 , the focal length of the eighth lens L8 and the focal length of the second fixed lens group G3 in the zoom lens satisfy: -25.44 ≤ F8 / F3 ≤ -25.24.

[0116] Wherein, F8 represents the focal length of the eighth lens L8, and F3 represents the focal length of the second fixed lens group G3.

[0117] Specifically, by matching the focal length of the eighth lens L8 with the focal length of the second fixed lens group G3 as described above, and at the same time reasonably matching the optical powers of the various lenses in the second fixed lens group G3, it can ensure that light passes smoothly through the second fixed lens group G3 and enters the focusing lens group G4, and at the same time can achieve certain purposes of chromatic aberration correction, distortion correction, and resolution improvement.

[0118] Reference Figure 1 - Figure 2 , a plane glass CG with a certain thickness is provided between the sixteenth lens L16 and the image plane IMA, which can not only play a protective role but also filter out unnecessary stray light, thereby improving the imaging quality of the zoom lens. For example, the imaging quality of the zoom lens can be improved by filtering out infrared light through the plane glass CG during the day.

[0119] In summary, for the zoom lens provided by the embodiment of the present application, through the reasonable matching of the optical powers, refractive indices, materials, etc. of the 5 lens groups, the aberration balance of each focal segment can be effectively achieved, ensuring the clarity of the image under different focal length states, and realizing the use requirements of small distortion, large aperture, and clear imaging on a 1 / 1.2″ target surface and in the wavelength band of 405nm - 656nm.

[0120] When the zoom lens provided by the embodiment of the present application is applied to an ITS lens, it has characteristics such as high resolution, low distortion, and high contrast, and can provide clear, accurate, and high-quality images. Its design takes into account aspects such as optical characteristics, mechanical structure, and electronic interface, and can effectively adapt to various complex environments.

[0121] The following further describes specific embodiments of the zoom lens applicable to the above embodiments with reference to the accompanying drawings.

[0122] Embodiment 1

[0123] Continue to refer to Figure 1 - Figure 2 As shown, a zoom lens provided in Embodiment 1 of the present application includes a first fixed lens group G1 with a positive optical power, a variable magnification lens group G2 with a negative optical power, a diaphragm STO, a second fixed lens group G3 with a positive optical power, a focusing lens group G4 with a negative optical power, a third fixed lens group G5 with a positive optical power, and a plane glass CG arranged in sequence along the optical axis from the object plane to the image plane; the first fixed lens group G1 and the second fixed lens group G3 are fixed, and the variable magnification lens group G2 and the focusing lens group move along the optical axis direction during zooming.

[0124] Along the optical axis from the object plane to the image plane direction:

[0125] The first fixed lens group G1 includes a first lens L1 with a negative optical power, a second lens L2 with a positive optical power, and a third lens L3 with a positive optical power.

[0126] The variable magnification lens group G2 includes a fourth lens L4 with a negative optical power, a fifth lens L5 with a negative optical power, a sixth lens L6 with a positive optical power, and a seventh lens L7 with a negative optical power; the seventh lens L7 is an aspherical lens.

[0127] The second fixed lens group G3 includes an eighth lens L8 with a positive optical power, a ninth lens L9 with a positive optical power, a tenth lens L10 with a negative optical power, and an eleventh lens L11 with a positive optical power; the eighth lens L8 is an aspherical lens.

[0128] The focusing lens group G4 includes a twelfth lens L12 with a negative optical power.

[0129] The third fixed lens group G5 includes a thirteenth lens L13 with a positive optical power, a fourteenth lens L14 with a negative optical power, a fifteenth lens L15 with a positive optical power, and a sixteenth lens L16 with a negative optical power; the thirteenth lens L13 is an aspherical lens.

[0130] The diaphragm position of the zoom lens remains consistent relative to the image plane position at different focal lengths, and the diaphragm aperture is the same at different focal lengths, and at the same time satisfies: F / EPD ≤ 1.50.

[0131] Wherein, F is the focal length of the zoom lens, and EPD is the entrance pupil diameter of the zoom lens in the state of focal length F.

[0132] Exemplarily, Table 1 details the specific optical physical parameters of each lens in the zoom lens provided in the first embodiment of the present application, and the zoom lens in Table 1 corresponds to Figure 1 and Figure 2 the zoom lens shown.

[0133] Table 1 Design values of the optical physical parameters of the zoom lens

[0134]

[0135]

[0136] Among them, the surface number S in Table 1 is numbered according to the surface order of each lens; "STO" represents the aperture of the zoom lens; IMA represents the image plane; the radius of curvature R represents the degree of curvature of the lens surface, a positive value indicates that the surface bends towards the image plane side, and a negative value indicates that the surface bends towards the object plane side; among them, "INF" indicates 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 refractive ability of the material between the current surface and the next surface to light, and a space represents that the current position is air with a refractive index of 1. The Abbe number vd represents the dispersion characteristic of the material between the current surface and the next surface to light; the semi-aperture represents half of the lens aperture. Among them, the more severe the medium dispersion, the smaller the Abbe number; conversely, the milder the medium dispersion, the larger the Abbe number.

[0137] Furthermore, Table 2 shows the numerical values of the zoom intervals of the zoom lens in Table 1 at the wide-angle end and the telephoto end, with the unit of millimeters (mm).

[0138] Design values of the variable spacing of the zoom lens in Table 2

[0139]

[0140]

[0141] Among them, the zoom intervals in Table 2 are different interval values of the zoom lens at the wide-angle end and the telephoto end.

[0142] Combined Figure 1 、 Figure 2 、as shown in Table 1 and Table 2, by adjusting the distances of the lens zoom intervals 1, 2, 3, and 4 at the wide-angle end and the telephoto end respectively, the zoom ratio of the zoom lens can be changed to make it have a larger zoom ratio.

[0143] In this embodiment, the aspherical lens of the zoom lens can satisfy the following formula:

[0144]

[0145] Among them, Z is the axial distance from the vertex of the surface at the position perpendicular to the optical axis with a height of r along the optical axis direction to the vertex of this surface; c represents the curvature at the vertex of the aspherical surface; a4, a6, a8, a10, a12, a14, a16 are the high-order aspherical coefficients of the fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth orders of the corresponding aspherical surface, and the combination of a_i r^i forms the high-order term of the corresponding aspherical surface, where i = 4, 6, 8, 10, 12, 14, 16.

[0146] Exemplarily, Table 3 details the aspherical coefficients of each lens in Embodiment 1 in a feasible implementation manner.

[0147] Table 3 Design values of aspherical coefficients of each lens in the zoom lens

[0148]

[0149]

[0150] Among them, -7.557695629923E-05 indicates that the coefficient a4 of the surface serial number S11 is -7.557695629923 * 10 -5 , and so on.

[0151] As shown in Table 4, the zoom lens of the first embodiment achieves the following technical indicators:

[0152] Table 4 Parameter indicators of the zoom lens of the first embodiment

[0153] Wide - angle end Tele - photo end Image plane size (mm) Φ13.10 Φ13.10 Focal length (mm) 14.99 50.00 Band (nm) 436-656 436-656 Overall optical length (mm) 120.00 120.00

[0154] Furthermore, the performance parameters of the zoom lens provided in the first embodiment are tested, and the test results are as follows:

[0155] The ray fan diagram is one of the commonly used evaluation methods for current optical designers. Figure 3 is the ray fan diagram of the wide-angle end of the optical system. Refer to Figure 3 . In a single figure, the abscissa is the normalized beam aperture, and the ordinate is the vertical aberration. Ideally, each curve should completely coincide with the horizontal axis. At this time, all rays in this field of view focus on the same point on the image plane; the ordinate in a single image can also be expressed as the maximum dispersion range of the beam on the ideal image plane. The ray fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also represent the magnitude of chromatic aberration. As can be seen from Figure 3 , at each field of view of the wide-angle end of this zoom lens, each wavelength is well close to the abscissa, indicating that the vertical aberration of each wavelength is well corrected. In addition, the curves of each color do not show obvious dispersion, indicating that this zoom lens also has good correction for chromatic aberration and meets the usage requirements of this zoom lens. Among them, Z17 in the attached drawings of the embodiments of the present application refers to the zoom lens, which will not be elaborated hereinafter.

[0156] Figure 4 is the field curvature and distortion curve diagram of the wide-angle end of the optical system. Refer to Figure 4 . In the left coordinate system, the horizontal coordinate represents the magnitude of the field curvature of the zoom lens, with the unit of mm; the vertical coordinate represents the normalized image height, without unit; where T represents meridional and S represents sagittal; during imaging, the image quality at the center and the image quality at the periphery have a small difference. In the right coordinate system, the horizontal coordinate represents the magnitude of distortion, with the unit of %; the vertical coordinate represents the normalized image height, without unit. As can be seen from Figure 4It can be seen that the distortion of the optical system provided in this embodiment is well corrected, with small imaging distortion, meeting the usage requirements of this zoom lens.

[0157] Figure 5 is the axial aberration curve at the wide-angle end of the optical system. Refer to Figure 5 , the vertical direction represents the normalization of the aperture, 0 represents on the optical axis, and the vertex in the sagittal direction represents the maximum pupil radius. The main wavelength is 546.074 nm, and the horizontal direction represents the offset relative to the main wavelength, with the unit of millimeter (mm). From Figure 5 it can be seen that the axial aberrations of the normalized apertures with different wavelengths from 0.3 to 1.0 are all controlled within a reasonable range, indicating that the axial aberration of this zoom lens at the wide-angle end is well controlled, meeting the usage requirements.

[0158] Figure 6 is the ray fan diagram at the telephoto end of the optical system. Refer to Figure 6 , in a single figure, the abscissa is the normalized beam aperture, and the ordinate is the lateral aberration. Ideally, each curve should completely coincide with the horizontal axis. At this time, all rays in this field of view focus on the same point on the image plane; the ordinate in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. The ray fan diagram can not only reflect the monochromatic aberrations of different wavelengths but also represent the magnitude of chromatic aberration. From Figure 6 it can be known that at the telephoto end of this zoom lens, each wavelength in each field of view is well close to the horizontal axis, indicating that the lateral aberrations of each wavelength are well corrected. In addition, the curves of each color do not show obvious dispersion, indicating that this zoom lens also has good correction for chromatic aberration, meeting the usage requirements of this zoom lens.

[0159] Figure 7 is the field curvature and distortion curve graph at the telephoto end of the optical system. Refer to Figure 7 , in the left coordinate system, the horizontal coordinate represents the magnitude of the field curvature of the zoom lens, with the unit of mm; the vertical coordinate represents the normalized image height, without unit; where T represents meridional and S represents sagittal. For the optical system provided in this embodiment, the light from a wavelength of 436 nm to 656 nm is effectively controlled in terms of field curvature, that is, when imaging, the image quality difference between the center and the periphery is small. In the right coordinate system, the horizontal coordinate represents the magnitude of distortion, with the unit of %; the vertical coordinate represents the normalized image height, without unit. From Figure 7 it can be seen that the distortion of the optical system provided in this embodiment is well corrected, with small imaging distortion, meeting the usage requirements of this zoom lens.

[0160] Figure 8 is the axial aberration curve at the telephoto end of the optical system. Refer to Figure 8, the vertical direction represents the normalization of the aperture, 0 represents on the optical axis, and the vertex in the vertical direction represents the maximum pupil radius; the main wavelength is 546.074 nm, and the horizontal direction represents the offset relative to the main wavelength, with the unit of millimeter (mm). From [[ID=7 it can be seen that the axial aberrations of the normalized apertures with different wavelengths from 0.3 to 1.0 are all controlled within a reasonable range, indicating that the axial aberrations of the zoom lens at the telephoto end are well controlled and meet the usage requirements.

[0161] Embodiment 2

[0162] ​ FIG. is a schematic structural diagram of the zoom lens provided in Embodiment 2 of the present application at the wide-angle end, ​ FIG. is a schematic structural diagram of the zoom lens provided in Embodiment 2 of the present application at the telephoto end. Referring to ​ and ​ , a zoom lens provided in Embodiment 2 of the present application includes a first fixed lens group G1 with a positive optical power, a variable magnification lens group G2 with a negative optical power, a stop STO, a second fixed lens group G3 with a positive optical power, a focusing lens group G4 with a negative optical power, a third fixed lens group G5 with a positive optical power, and a plane glass CG, which are arranged in sequence along the optical axis from the object plane to the image plane; the first fixed lens group G1 and the second fixed lens group G3 are fixed, and the variable magnification lens group G2 and the focusing lens group move along the optical axis direction during zooming.

[0163] Along the optical axis from the object plane to the image plane direction:

[0164] The first fixed lens group G1 includes a first lens L1 with a negative optical power, a second lens L2 with a positive optical power, and a third lens L3 with a positive optical power.

[0165] The variable magnification lens group G2 includes a fourth lens L4 with a negative optical power, a fifth lens L5 with a negative optical power, a sixth lens L6 with a positive optical power, and a seventh lens L7 with a negative optical power; the seventh lens L7 is an aspherical lens.

[0166] The second fixed lens group G3 includes an eighth lens L8 with a positive optical power, a ninth lens L9 with a positive optical power, a tenth lens L10 with a negative optical power, and an eleventh lens L11 with a positive optical power; the eighth lens L8 is an aspherical lens.

[0167] The focusing lens group G4 includes a twelfth lens L12 with a negative optical power.

[0168] The third fixed lens group G5 includes a thirteenth lens L13 with a positive optical power, a fourteenth lens L14 with a negative optical power, a fifteenth lens L15 with a positive optical power, and a sixteenth lens L16 with a negative optical power; the thirteenth lens L13 is an aspherical lens.

[0169] The diaphragm position of the zoom lens remains consistent with respect to the image plane position at different focal lengths, and the diaphragm aperture is the same at different focal lengths, while satisfying: F / EPD ≤ 1.50.

[0170] Wherein, F is the focal length of the zoom lens, and EPD is the entrance pupil diameter of the zoom lens in the state of focal length F.

[0171] Exemplarily, Table 5, in a feasible implementation manner, details the specific optical physical parameters of each lens in the zoom lens provided in the second embodiment of the present application. The zoom lens in Table 5 corresponds to ​ and ​ the zoom lens shown.

[0172] Table 5 Design values of the optical physical parameters of the zoom lens

[0173]

[0174]

[0175] Wherein, the surface number S in Table 5 is numbered according to the surface order of each lens; "STO" represents the diaphragm STO of the zoom lens; IMA represents the image plane; the radius of curvature R represents the degree of curvature of the lens surface, a positive value represents that the surface bends towards the image plane side, and a negative value represents that the surface bends towards the object plane side; wherein "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 space represents that the current position is air and the refractive index is 1. The Abbe number vd represents the dispersion characteristic of the material between the current surface and the next surface to light; the semi-aperture represents half of the lens aperture. Among them, the more severe the medium dispersion, the smaller the Abbe number; conversely, the milder the medium dispersion, the larger the Abbe number.

[0176] Table 6 shows the numerical values of the zoom intervals of the zoom lens in Table 5 at the wide-angle end and the telephoto end, with the unit of millimeters (mm).

[0177] Table 6 Design values of the variable spacing of the zoom lens

[0178] ​ ​ ​ 0.1632 32.6943 ​ 32.9734 0.4423 ​ 0.4999 1.4974 ​ 8.0662 7.0689

[0179] Wherein, the zoom interval in Table 6 is the different interval values of the zoom lens at the wide-angle end and the telephoto end.

[0180] Combined with ​ and ​ as shown in Table 5 and Table 6, by adjusting the distances of the lens zoom intervals 1, 2, 3, and 4 at the wide-angle end and the telephoto end respectively, the zoom ratio of the zoom lens can be changed to make it have a larger zoom ratio.

[0181] In this embodiment, the aspherical lens of the zoom lens can satisfy the following formula:

[0182]

[0183] Where Z is the axial distance from the vertex of the surface to the vertex of the surface at a position perpendicular to the optical axis with a height of r along the optical axis direction; c represents the curvature at the vertex of the aspherical surface; a4, a6, a8, a10, a12, a14, a16 are the high-order aspherical coefficients of the fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth orders of the corresponding aspherical surface, and the combination of a_i r^i forms the high-order term of the corresponding aspherical surface, where i = 4, 6, 8, 10, 12, 14, 16.

[0184] Exemplarily, Table 7 details the aspherical coefficients of each lens in Embodiment 2 of the present application in a feasible implementation manner.

[0185] Table 7 Design values of aspherical coefficients of each lens in the zoom lens

[0186]

[0187]

[0188]

[0189] Among them, -6.583487059829E-05 means that the coefficient a4 of the surface serial number S12 is -6.583487059829 * 10^-5, and so on.

[0190] As shown in Table 8, the zoom lens of Embodiment 2 achieves the following technical indicators:

[0191] Table 8 Technical indicators of the zoom lens

[0192] ​ ​ ​ ​ ​ ​ 15.00 50.00 ​ 436-656 436-656 ​ 120.00 120.00

[0193] Furthermore, the performance parameters of the zoom lens provided in Embodiment 2 are tested, and the test results are as follows:

[0194] The ray fan diagram is one of the commonly used evaluation methods by optical designers at present. ​ is the ray fan diagram of the wide-angle end of the optical system. Refer to ​ , in a single figure, the abscissa is the normalized beam aperture, and the ordinate is the vertical aberration. Ideally, each curve should coincide exactly with the horizontal axis. At this time, all rays in this field of view are focused at the same point on the image plane; the ordinate in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. The ray fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also represent the magnitude of chromatic aberration. From ​It can be seen that in the wide-angle end of this zoom lens, at each field of view and each wavelength, it is better close to the abscissa, indicating that the vertical aberration of each wavelength is well corrected. In addition, the curves of each color do not have obvious dispersion, indicating that this zoom lens also has good correction for chromatic aberration, meeting the usage requirements of this zoom lens.

[0195] ​ It is the field curvature and distortion curve graph of the wide-angle end of the optical system. Refer to ​ , in the coordinate system on the left side of the two figures, the horizontal coordinate represents the magnitude of the field curvature of the zoom lens, with the unit of mm; the vertical coordinate represents the normalized image height, without unit; where T represents meridian and S represents sagittal. The optical system provided in this embodiment effectively controls the light from a wavelength of 436nm to 656nm in terms of field curvature, that is, when imaging, the image quality difference between the center and the periphery is small. In the coordinate system on the right side, the horizontal coordinate represents the magnitude of distortion, with the unit of %; the vertical coordinate represents the normalized image height, without unit. From ​ it can be seen that the distortion of the optical system provided in this embodiment is well corrected, and the imaging distortion is small, meeting the usage requirements of this zoom lens.

[0196] ​ The axial aberration curve of the wide-angle end of the optical system. Refer to ​ as shown, the vertical direction represents the normalization of the aperture, 0 represents on the optical axis, and the vertex in the vertical direction represents the maximum pupil radius; the main wavelength uses 546.074nm, and the horizontal direction represents the offset relative to the main wavelength, with the unit of millimeter (mm). From ​ it can be seen that the axial aberrations of the normalized apertures of different wavelengths from 0.3 to 1.0 are all controlled within a reasonable range, indicating that the axial aberration of this zoom lens at the wide-angle end is well controlled, meeting the usage requirements.

[0197] ​ The ray fan diagram of the telephoto end of the optical system. Refer to ​ , in a single figure, the abscissa is the normalized beam aperture, and the ordinate is the vertical aberration. Ideally, each curve should completely coincide with the horizontal axis, and at this time, all rays in this field of view focus on the same point on the image plane; the ordinate in a single image can also be expressed as the maximum dispersion range of the beam on the ideal image plane. The ray fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also represent the magnitude of chromatic aberration. From ​ it can be seen that in the telephoto end of this zoom lens, at each field of view and each wavelength, it is better close to the abscissa, indicating that the vertical aberration of each wavelength is well corrected. In addition, the curves of each color do not have obvious dispersion, indicating that this zoom lens also has good correction for chromatic aberration, meeting the usage requirements of this zoom lens.

[0198] ​ It is the field curvature and distortion curve graph of the telephoto end of the optical system. Refer to​ In the left coordinate system, the horizontal coordinate represents the magnitude of the field curvature of the zoom lens, with the unit of mm; the vertical coordinate represents the normalized image height, without unit; where T represents the meridian and S represents the sagittal. The optical system provided in this embodiment effectively controls the light from a wavelength of 436 nm to 656 nm in terms of field curvature, that is, when imaging, the difference in image quality between the center and the periphery is small; in the right coordinate system, the horizontal coordinate represents the magnitude of distortion, with the unit of %; the vertical coordinate represents the normalized image height, without unit. From ​ it can be seen that the distortion of the optical system provided in this embodiment is well corrected, and the imaging distortion is small, meeting the usage requirements of the zoom lens.

[0199] ​ The axial aberration curve at the telephoto end of the optical system. Refer to ​ , the vertical direction represents the normalization of the aperture, 0 represents on the optical axis, and the vertex in the vertical direction represents the maximum pupil radius; the principal wavelength uses 546.074 nm, and the horizontal direction represents the offset relative to the principal wavelength, with the unit of millimeters (mm). From ​ it can be seen that the axial aberrations of the normalized apertures with different wavelengths from 0.3 to 1.0 are all controlled within a reasonable range, indicating that the axial aberration of the zoom lens at the telephoto end is well controlled and meets the usage requirements.

[0200] Embodiment III

[0201] ​ is a schematic structural diagram of the zoom lens provided in Embodiment III of the present application at the wide-angle end, ​ is a schematic structural diagram of the zoom lens provided in Embodiment III of the present application at the telephoto end. Refer to ​ and ​ , a zoom lens provided in Embodiment III of the present application includes a first fixed lens group G1 with a positive optical power, a variable magnification lens group G2 with a negative optical power, a stop STO, a second fixed lens group G3 with a positive optical power, a focusing lens group G4 with a negative optical power, a third fixed lens group G5 with a positive optical power, and a plane glass CG arranged in sequence along the optical axis from the object plane to the image plane; the first fixed lens group G1 and the second fixed lens group G3 are fixed, and the variable magnification lens group G2 and the focusing lens group move along the optical axis direction during zooming.

[0202] Along the optical axis from the object plane to the image plane direction:

[0203] The first fixed lens group G1 includes a first lens L1 with a negative optical power, a second lens L2 with a positive optical power, and a third lens L3 with a positive optical power.

[0204] The variable magnification lens group G2 includes a fourth lens L4 with a negative optical power, a fifth lens L5 with a negative optical power, a sixth lens L6 with a positive optical power, and a seventh lens L7 with a negative optical power; the seventh lens L7 is an aspherical lens.

[0205] The second fixed lens group G3 includes an eighth lens L8 with a positive optical power, a ninth lens L9 with a positive optical power, a tenth lens L10 with a negative optical power, and an eleventh lens L11 with a positive optical power; the eighth lens L8 is an aspherical lens.

[0206] The focusing lens group G4 includes a twelfth lens L12 with a negative optical power.

[0207] The third fixed lens group G5 includes a thirteenth lens L13 with a positive optical power, a fourteenth lens L14 with a negative optical power, a fifteenth lens L15 with a positive optical power, and a sixteenth lens L16 with a negative optical power; the thirteenth lens L13 is an aspherical lens.

[0208] The diaphragm position of the zoom lens remains consistent relative to the image plane position at different focal lengths, and the diaphragm aperture is the same at different focal lengths, and at the same time satisfies: F / EPD ≤ 1.50.

[0209] Wherein, F is the focal length of the zoom lens, and EPD is the entrance pupil diameter of the zoom lens in the state of F focal length.

[0210] Exemplarily, Table 9 details the specific optical physical parameters of each lens in the zoom lens provided in the third embodiment of the present application in a feasible implementation manner. The zoom lens in Table 9 corresponds to ​ and ​ the zoom lens shown.

[0211] Table 9 Design values of the optical physical parameters of the zoom lens

[0212]

[0213]

[0214] Among them, the surface number S in Table 9 is numbered according to the surface order of each lens; "STO" represents the aperture STO of the zoom lens; IMA represents the image plane; the radius of curvature R represents the degree of curvature of the lens surface, a positive value represents that the surface bends towards the image plane side, and a negative value represents that the surface bends towards the object plane side; among them, "INF" indicates 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 the 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 light; the semi-aperture represents half of the lens aperture. Among them, the more severe the medium dispersion, the smaller the Abbe number; conversely, the milder the medium dispersion, the larger the Abbe number.

[0215] Table 10 shows the numerical values of the zoom intervals of the zoom lens in Table 9 at the wide-angle end and the telephoto end, with the unit of millimeters (mm).

[0216] Table 10 Design values of the variable spacing of the zoom lens

[0217] ​ ​ ​ 0.1632 32.6943 ​ 32.9734 0.4423 ​ 0.5155 0.5 ​ 8.0506 8.1663

[0218] Among them, the zoom interval in Table 10 is the different interval values of the zoom lens at the wide-angle end and the telephoto end.

[0219] Combined ​ and ​ As shown in Table 9 and Table 10, by adjusting the distances of the lens zoom intervals 1, 2, 3, and 4 at the wide-angle end and the telephoto end respectively, the zoom ratio of the zoom lens is changed to make it have a larger zoom ratio.

[0220] In this embodiment, the aspherical lens of the zoom lens can satisfy the following formula:

[0221]

[0222] Among them, Z is the axial distance from the surface at the position perpendicular to the optical axis with a height of r along the optical axis direction to the vertex of this surface; c represents the curvature at the vertex of the aspherical surface; a4, a6, a8, a10, a12, a14, a16 are the high-order aspherical coefficients of the fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth orders of the corresponding aspherical surface, and the combination of a_i r^i becomes the high-order term of the corresponding aspherical surface, where i = 4, 6, 8, 10, 12, 14, 16.

[0223] Exemplarily, Table 11 details the aspherical coefficients of each lens in Embodiment 3 of the present application in a feasible implementation manner.

[0224] Table 11 Design values of the aspherical coefficients of each lens in the zoom lens

[0225]

[0226]

[0227]

[0228] Among them, -1.127436117376E-04 indicates that the coefficient a4 of the surface serial number S11 is -1.127436117376×10 -4 , and so on.

[0229] As shown in Table 12, the zoom lens of the third embodiment has achieved the following technical indicators:

[0230] Table 12 Technical indicators of the zoom lens

[0231] ​ ​ ​ ​ ​ ​ 14.99 50.00 ​ 436-656 436-656 ​ 120.00 120.00

[0232] Furthermore, the performance parameters of the zoom lens provided in the third embodiment are tested, and the test results are as follows:

[0233] ​ The light fan diagram of the wide-angle end of the optical system. Refer to ​ , in a single figure, the abscissa is the normalized beam aperture, and the ordinate is the vertical aberration. Ideally, each curve should completely coincide with the horizontal axis. At this time, all the light rays in this field of view are focused on the same point on the image plane; the ordinate in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also represent the magnitude of chromatic aberration. From ​ it can be seen that in each field of view at the wide-angle end of this zoom lens, each wavelength is well close to the abscissa, indicating that the vertical aberration of each wavelength is well corrected. In addition, the curves of each color do not have obvious dispersion, indicating that this zoom lens also has good correction for chromatic aberration and meets the usage requirements of this zoom lens.

[0234] ​ The field curvature and distortion curve diagram of the wide-angle end of the optical system. Refer to ​ , in the left coordinate system of the two figures, the horizontal coordinate represents the magnitude of the field curvature of the zoom lens, and the unit is mm; the vertical coordinate represents the normalized image height, without unit; where T represents meridian and S represents sagittal. The optical system provided in this embodiment effectively controls the light from 436 nm to 656 nm in terms of field curvature, that is, when imaging, the image quality at the center and the image quality at the periphery have a small difference; in the right coordinate system, the horizontal coordinate represents the magnitude of distortion, and the unit is %; the vertical coordinate represents the normalized image height, without unit. From ​It can be seen that the distortion of the optical system provided in this embodiment is well corrected, with small imaging distortion, meeting the usage requirements of this zoom lens.

[0235] ​ The axial aberration curve at the wide-angle end of the optical system. Refer to ​ , the vertical direction represents the normalization of the aperture, 0 represents on the optical axis, and the vertex in the sagittal direction represents the maximum pupil radius; the principal wavelength is 546.074 nm, and the horizontal direction represents the offset relative to the principal wavelength, with the unit of millimeter (mm). From ​ it can be seen that the axial aberrations of the normalized apertures with different wavelengths from 0.3 to 1.0 are all controlled within a reasonable range, indicating that the axial aberration of this zoom lens at the wide-angle end is well controlled, meeting the usage requirements.

[0236] ​ The ray fan diagram at the telephoto end of the optical system. Refer to ​ , in a single figure, the abscissa is the normalized beam aperture, and the ordinate is the lateral aberration. Ideally, each curve should completely coincide with the horizontal axis, and at this time, all rays in this field of view focus on the same point on the image plane; the ordinate in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. The ray fan diagram can not only reflect the monochromatic aberration of different wavelengths but also represent the magnitude of chromatic aberration. From ​ it can be known that at the telephoto end of this zoom lens, each wavelength at each field of view is well close to the horizontal axis, indicating that the lateral aberration of each wavelength is well corrected. In addition, the curves of each color do not show obvious dispersion, indicating that this zoom lens also has good correction for chromatic aberration, meeting the usage requirements of this zoom lens.

[0237] ​ The field curvature and distortion curve diagram at the telephoto end of the optical system. Refer to ​ , in the coordinate system on the left side of the two figures, the horizontal coordinate represents the magnitude of the field curvature of the zoom lens, with the unit of mm; the vertical coordinate represents the normalized image height, without a unit; where T represents meridional and S represents sagittal. For the optical system provided in this embodiment, the light from a wavelength of 436 nm to 656 nm is effectively controlled in terms of field curvature, that is, when imaging, the image quality at the center and the periphery has a small difference; in the coordinate system on the right side, the horizontal coordinate represents the magnitude of distortion, with the unit of %; the vertical coordinate represents the normalized image height, without a unit. From ​ it can be seen that the distortion of the optical system provided in this embodiment is well corrected, with small imaging distortion, meeting the usage requirements of this zoom lens.

[0238] ​ The axial aberration curve at the telephoto end of the optical system. Refer to ​, the vertical direction represents the normalization of the aperture, 0 represents on the optical axis, and the vertex in the vertical direction represents the maximum pupil radius; the main wavelength is 546.074 nm, and the horizontal direction represents the offset relative to the main wavelength, with the unit of millimeter (mm). From ​ It can be seen that the axial aberrations of the normalized apertures with different wavelengths from 0.3 to 1.0 are all controlled within a reasonable range, indicating that the axial aberrations of this zoom lens at the telephoto end are well controlled and meet the usage requirements.

[0239] In summary, in the first embodiment, the second embodiment, and the third embodiment of the present application, the optical physical parameters of the first lens to the sixteenth lens are shown in Table 13.

[0240] Table 13 Design values of the optical physical parameters of the zoom lens

[0241]

[0242] Note that the above is only the preferred embodiment of the present utility model and the applied technical principle. Those skilled in the art will understand that the present application is not limited to the specific embodiments described here. Various obvious changes, re-adjustments, mutual combinations, and substitutions can be made by those skilled in the art without departing from the protection scope of the present application. Therefore, although the present application has been described in detail through the above embodiments, the present application is not limited to the above embodiments. Without departing from the concept of the present application, more other equivalent embodiments can be included, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A zoom lens, characterized in that, It includes a first fixed lens group with a positive optical power, a variable magnification lens group with a negative optical power, a diaphragm, a second fixed lens group with a positive optical power, a focusing lens group with a negative optical power, and a third fixed lens group with a positive optical power, which are arranged in sequence along the optical axis from the object plane to the image plane; the first fixed lens group and the second fixed lens group are fixed, and the variable magnification lens group and the focusing lens group move along the optical axis direction during zooming; Along the optical axis from the object plane to the image plane direction: The first fixed lens group includes a first lens with a negative optical power, a second lens with a positive optical power, and a third lens with a positive optical power; The variable magnification lens group includes a fourth lens with a negative optical power, a fifth lens with a negative optical power, a sixth lens with a positive optical power, and a seventh lens with a negative optical power; the seventh lens is an aspherical lens; The second fixed lens group includes an eighth lens with a positive optical power, a ninth lens with a positive optical power, a tenth lens with a negative optical power, and an eleventh lens with a positive optical power; the eighth lens is an aspherical lens; The focusing lens group includes a twelfth lens with a negative optical power; The third fixed lens group includes a thirteenth lens with a positive optical power, a fourteenth lens with a negative optical power, a fifteenth lens with a positive optical power, and a sixteenth lens with a negative optical power; the thirteenth lens is an aspherical lens; The diaphragm position of the zoom lens remains consistent with respect to the image plane position at different focal lengths, and the diaphragm aperture is the same at different focal lengths, and at the same time satisfies: F / EPD ≤ 1.50; Wherein, F is the focal length of the zoom lens, and EPD is the entrance pupil diameter of the zoom lens in the state of F focal length.

2. The zoom lens according to claim 1, characterized in that, Along the direction of the optical axis from the object side to the image side, the surface of the lens close to the object plane side is the object side surface, and the surface of the lens close to the image plane side is the image side surface; In the first fixed lens group, the surface type of the first lens is convex-concave; the surface type of the second lens is convex-convex; the surface type of the third lens is convex-concave or convex-flat; In the variable magnification lens group, the image side surface of the fourth lens is concave, the surface type of the fifth lens is concave-concave, the object side surface of the sixth lens is convex, and the object side surface of the seventh lens is concave; In the second fixed lens group, the surface type of the eighth lens is convex-concave, the surface type of the ninth lens is convex-convex, the surface type of the tenth lens is convex-concave; the surface type of the eleventh lens is convex-convex; In the focusing lens group, the surface type of the twelfth lens is convex-concave; In the third fixed lens group, the image side surface of the thirteenth lens is convex at the center, the image side surface of the fourteenth lens is concave; the image side surface of the fifteenth lens is convex-convex, and the surface type of the sixteenth lens is concave-concave.

3. The zoom lens according to claim 1, wherein 5.44 ≤ F1 / FW ≤ 5.49; -1.70 ≤ F2 / FW ≤ -1.68; 1.78 ≤ F3 / FW ≤ 1.89; -8.64 ≤ F4 / FW ≤ -6.45; 3.62 ≤ F5 / FW ≤ 6.55; Wherein, F1, F2, F3, F4, and F5 are the focal lengths of the first fixed lens group, the zoom lens group, the second fixed lens group, the focusing lens group, and the third fixed lens group, respectively; FW is the focal length of the wide-angle end of the zoom lens.

4. The zoom lens according to claim 1, wherein 5.30 ≤ S2 / S4 ≤ 6.22; 0.43 ≤ S4 / TTL ≤ 0.52; Wherein, S2 is the maximum distance that the zoom lens group moves along the optical axis direction, S4 is the maximum distance that the focusing lens group moves along the optical axis direction; TTL represents the total length of the zoom lens.

5. The zoom lens according to claim 1, wherein Vd7 ≥ 63.9; Vd8 ≥ 63.9; Wherein, Vd7 is the Abbe number of the seventh lens, and Vd8 is the Abbe number of the eighth lens.

6. The zoom lens according to claim 1, wherein -25.44 ≤ F8 / F3 ≤ -25.24; Wherein, F8 represents the focal length of the eighth lens, and F3 represents the focal length of the second fixed lens group.

7. The zoom lens according to claim 1, wherein The first lens and the second lens are combined into a doublet lens group.

8. The zoom lens according to claim 1, wherein The fifth lens and the sixth lens of the zoom lens group are combined into a doublet lens group.

9. The zoom lens according to claim 1, characterized in that, The tenth lens and the eleventh lens of the second fixed lens group are combined into a doublet lens group.

10. The zoom lens according to claim 1, characterized in that, The thirteenth lens and the fourteenth lens of the third fixed lens group are combined into a doublet lens group.

Images