A zoom lens

Abstract

The utility model discloses a zoom lens. The zoom lens comprises a focusing lens group with negative focal length, an aperture, a variable power lens group with positive focal length and a fixed lens group with negative focal length arranged in sequence along an optical axis from an object side to an image side; the focusing lens group comprises a first lens, a second lens and a third lens with negative, negative and positive focal lengths in sequence; the variable power lens group comprises a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens with positive, positive, positive, negative, positive and positive focal lengths in sequence; the fixed lens group comprises a tenth lens and an eleventh lens with negative and positive focal lengths respectively, and a three-group-element zoom optical system is realized. The zoom lens is composed of five glass spherical lenses, six plastic aspherical lenses and a flat glass with a certain thickness, and the use requirements of small volume, large aperture and clear imaging in the 436nm-850nm wave band under the 1 / 2.8" target surface are realized.

Description

Technical Field

[0001] This utility model relates to the field of optical lens technology, and in particular to a zoom lens. Background Technology

[0002] In fields such as security monitoring and drone aerial photography, zoom lenses have been widely used due to their advantages such as long shooting distance and wide shooting angle. Furthermore, with technological advancements, cameras are gradually moving towards miniaturization and higher precision, which places even stricter demands on mainstream zoom lenses.

[0003] Currently, zoom lenses used in security monitoring, drone aerial photography, and other fields still have many shortcomings, such as a large number of lenses, low imaging resolution, small imaging surface, small aperture, and large size. Utility Model Content

[0004] This invention provides a zoom lens that improves image quality and meets the needs for clear imaging while achieving performance requirements such as large aperture, small size, and large target surface.

[0005] This utility model embodiment provides a zoom lens, including a focusing lens group with negative optical power, an aperture, a zoom lens group with positive optical power, and a fixed lens group with negative optical power, arranged sequentially along the optical axis from the object side to the image side.

[0006] The focusing lens group includes a first lens with negative optical power, a second lens with negative optical power, and a third lens with positive optical power;

[0007] The zoom lens group includes a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with positive optical power, a seventh lens with negative optical power, an eighth lens with positive optical power, and a ninth lens with positive optical power.

[0008] The fixed lens group includes a tenth lens with negative optical power and an eleventh lens with positive optical power;

[0009] The fixed lens group is fixedly arranged, while the focusing lens group and the zoom lens group are movable. When the zoom lens changes between the short focal length end and the long focal length end, the focusing lens group and the zoom lens group move synchronously and cooperatively along the optical axis.

[0010] Optionally, in the focusing lens group, the first lens is a spherical lens, and the second and third lenses are aspherical lenses;

[0011] In the zoom lens group, the sixth lens, the seventh lens, and the eighth lens are all spherical lenses, while the fourth lens, the fifth lens, and the ninth lens are all aspherical lenses.

[0012] In the fixed lens group, the tenth lens is a spherical lens, and the eleventh lens is an aspherical lens.

[0013] Optionally, in the focusing lens group, the first lens is a convex-concave lens, the second lens is a concave-concave lens, and the third lens is a convex-concave lens or a convex-convex lens;

[0014] In the zoom lens group, the fourth lens is a convex-convex lens, the fifth lens is a convex-concave lens, the sixth lens is a convex-convex lens, the seventh lens is a concave-concave lens, the eighth lens is a convex-concave lens, and the ninth lens is a convex-concave lens or a convex-convex lens.

[0015] In the fixed lens group, the tenth lens is a concave-concave lens, and the eleventh lens is a convex-convex lens.

[0016] Optionally, the zoom optics satisfy the following conditions:

[0017] -3.013≤FG1 / FW≤-2.791;

[0018] 2.650≤FG2 / FW≤2.759;

[0019] -27.265≤FG3 / FW≤-13.112;

[0020] FT / FW = 3.531;

[0021] Wherein, FG1, FG2, and FG3 are the focal lengths of the focusing lens group, the zoom lens group, and the fixed lens group, respectively; FW is the focal length at the short focal length end of the zoom lens; and FT is the focal length at the long focal length end of the zoom lens.

[0022] Optionally, the zoom optics satisfy the following condition: 1.510≤F4 / FG2≤2.757;

[0023] Wherein, F4 is the focal length of the fourth lens, and FG2 is the focal length of the zoom lens group.

[0024] Optionally, the seventh lens and the eighth lens are cemented together to form a cemented doublet lens group, or the sixth lens, the seventh lens, and the eighth lens are cemented together to form a cemented triplet lens group.

[0025] Optionally, the sixth lens, the seventh lens, and the eighth lens satisfy the following conditions:

[0026] 1.437≤nd6≤1.713; 53.94≤vd6≤95.12;

[0027] 1.604≤nd7≤2.04; 24.08≤vd7≤28.24;

[0028] 1.437≤nd8≤1.713;53.94≤vd8≤95.12;

[0029] Wherein, nd6, nd7, and nd8 are the refractive indices of the sixth, seventh, and eighth lenses, respectively, and vd6, vd7, and vd8 are the Abbe numbers of the sixth, seventh, and eighth lenses, respectively.

[0030] Optionally, the zoom lens satisfies the following conditions: WFNO ≤ 1.6; TFNO ≤ 3.3;

[0031] Wherein, WFNO is the aperture number at the short focal length end of the zoom lens, and TFNO is the aperture number at the long focal length end of the zoom lens.

[0032] Optionally, the zoom optics satisfy the following condition: 2.724≤S1 / S2≤2.943;

[0033] Wherein, S1 is the maximum movable distance of the focusing lens group, and S2 is the maximum movable distance of the zoom lens group.

[0034] Optionally, the zoom lens satisfies the following condition: 3.054≤TTL / S1≤3.221;

[0035] Wherein, TTL is the total optical length of the zoom lens, and S1 is the maximum movable distance of the focusing lens group.

[0036] The technical solution of this utility model embodiment is achieved by setting up a focusing lens group with negative optical power, an aperture stop, a zoom lens group with positive optical power, and a fixed lens group with negative optical power, arranged sequentially from the object side to the image side along the optical axis. The focusing lens group includes a first lens with negative optical power, a second lens with negative optical power, and a third lens with positive optical power. The zoom lens group includes a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with positive optical power, a seventh lens with negative optical power, an eighth lens with positive optical power, and a ninth lens with positive optical power. The fixed lens group includes a tenth lens with negative optical power and an eleventh lens with positive optical power. The fixed lens group is fixedly set, while the focusing lens group and the zoom lens group are movable. When the zoom lens changes between the short focal length end and the long focal length end, the focusing lens group and the zoom lens group move synchronously and cooperatively along the optical axis, thus realizing a three-element zoom optical system. This zoom lens consists of 5 glass spherical lenses, 6 plastic aspherical lenses, and a certain thickness of flat glass. It can improve image quality while meeting performance requirements such as large aperture, small size, and large target surface. It achieves the usage requirements of small size, large aperture, and clear imaging in the 436nm-850nm band under a 1 / 2.8″ target surface. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of a zoom lens at the short focal length end provided in Embodiment 1 of this utility model;

[0038] Figure 2 This is a schematic diagram of the structure of a zoom lens at the telephoto end provided in Embodiment 1 of this utility model;

[0039] Figure 3 The vertical chromatic aberration curve of the zoom lens at the short focal length end provided in Embodiment 1 of this utility model;

[0040] Figure 4 The vertical chromatic aberration curve of the zoom lens at the telephoto end provided in Embodiment 1 of this utility model;

[0041] Figure 5 This is a ray fan pattern of the zoom lens at the short focal length end provided in Embodiment 1 of this utility model;

[0042] Figure 6 This is a ray fan diagram of the zoom lens at the telephoto end provided in Embodiment 1 of this utility model;

[0043] Figure 7 The MTF curve of the zoom lens at the short focal length end provided in Embodiment 1 of this utility model;

[0044] Figure 8 The MTF curve of the zoom lens at the telephoto end provided in Embodiment 1 of this utility model;

[0045] Figure 9 The axial aberration curve of the zoom lens at the short focal length end provided in Embodiment 1 of this utility model;

[0046] Figure 10 The axial aberration curve of the zoom lens at the telephoto end provided in Embodiment 1 of this utility model;

[0047] Figure 11 This is a schematic diagram of the structure of a zoom lens at the short focal length end according to Embodiment 2 of this utility model;

[0048] Figure 12 This is a schematic diagram of the structure of a zoom lens at the telephoto end according to Embodiment 2 of this utility model;

[0049] Figure 13 The vertical chromatic aberration curve of the zoom lens at the short focal length end provided in Embodiment 2 of this utility model;

[0050] Figure 14 The vertical chromatic aberration curve of the zoom lens at the telephoto end provided in Embodiment 2 of this utility model;

[0051] Figure 15 This is a ray fan pattern of the zoom lens at the short focal length end provided in Embodiment 2 of this utility model;

[0052] Figure 16 This is a ray fan diagram of the zoom lens at the telephoto end provided in Embodiment 2 of this utility model;

[0053] Figure 17 The MTF curve of the zoom lens at the short focal length end provided in Embodiment 2 of this utility model;

[0054] Figure 18 The MTF curve of the zoom lens at the telephoto end provided in Embodiment 2 of this utility model;

[0055] Figure 19 The axial aberration curve of the zoom lens at the short focal length end provided in Embodiment 2 of this utility model;

[0056] Figure 20 The axial aberration curve of the zoom lens at the telephoto end provided in Embodiment 2 of this utility model;

[0057] Figure 21 This is a schematic diagram of the structure of a zoom lens at the short focal length end provided in Embodiment 3 of this utility model;

[0058] Figure 22 This is a schematic diagram of the structure of a zoom lens at the telephoto end provided in Embodiment 3 of this utility model;

[0059] Figure 23 The vertical chromatic aberration curve of the zoom lens at the short focal length end provided in Embodiment 3 of this utility model;

[0060] Figure 24 The vertical chromatic aberration curve of the zoom lens at the telephoto end provided in Embodiment 3 of this utility model;

[0061] Figure 25 This is a ray fan pattern of the zoom lens at the short focal length end provided in Embodiment 3 of this utility model;

[0062] Figure 26 This is a ray fan diagram of the zoom lens at the telephoto end provided in Embodiment 3 of this utility model;

[0063] Figure 27 The MTF curve of the zoom lens at the short focal length end provided in Embodiment 3 of this utility model;

[0064] Figure 28 The MTF curve of the zoom lens at the telephoto end provided in Embodiment 3 of this utility model;

[0065] Figure 29 The axial aberration curve of the zoom lens at the short focal length end provided in Embodiment 3 of this utility model;

[0066] Figure 30 The axial aberration curve of the zoom lens at the telephoto end provided in Embodiment 3 of this utility model. Detailed Implementation

[0067] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0068] The terminology used in the embodiments of this utility model is for the purpose of describing specific embodiments only and is not intended to limit the utility model. It should be noted that directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this utility model are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this utility model. Furthermore, in the context, it should be understood that when referring to an element being formed "upper" or "lower" of another element, it can be formed not only directly "upper" or "lower" of the other element, but also indirectly "upper" or "lower" of the other element through an intermediate element. The terms "first," "second," etc., are used for descriptive purposes only and do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0069] The term "comprising" and its variations as used in this utility model are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment".

[0070] It should be noted that the concepts of "first" and "second" mentioned in this utility model are only used to distinguish the corresponding contents and are not used to limit the order or interdependence.

[0071] It should be noted that the terms "a" and "a plurality of" used in this utility model are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0072] Figure 1 This is a schematic diagram of the structure of a zoom lens at the short focal length end according to Embodiment 1 of this utility model. Figure 2 This is a schematic diagram of the structure of a zoom lens at the telephoto end according to Embodiment 1 of this utility model, for reference. Figure 1 and Figure 2 The zoom lens includes a focusing lens group 100 with negative optical power, an aperture, a zoom lens group 200 with positive optical power, and a fixed lens group 300 with negative optical power, arranged sequentially along the optical axis from the object side to the image side.

[0073] The focusing lens group 100 includes a first lens 1 with negative optical power, a second lens 2 with negative optical power, and a third lens 3 with positive optical power; the zoom lens group 200 includes a fourth lens 4 with positive optical power, a fifth lens 5 with positive optical power, a sixth lens 6 with positive optical power, a seventh lens 7 with negative optical power, an eighth lens 8 with positive optical power, and a ninth lens 9 with positive optical power; the fixed lens group 300 includes a tenth lens 10 with negative optical power and an eleventh lens with positive optical power.

[0074] The fixed lens group 300 is fixedly set, while the focusing lens group 100 and the zoom lens group 200 are movable. When the zoom lens changes between the short focal length end and the long focal length end, the focusing lens group 100 and the zoom lens group 200 move synchronously and cooperatively along the optical axis.

[0075] First, it's understandable that optical power equals the difference between the convergence of the image-side beam and the convergence of the object-side beam; it characterizes the ability of an optical system to deflect light. The larger the absolute value of optical power, the stronger the bending ability of light; the smaller the absolute value, the weaker the bending ability. When optical power is positive, the refraction of light is converging; when optical power is negative, the refraction of light is diverging. Optical power can be used to characterize a single refractive surface of a lens (i.e., one surface of the lens), a single lens or lens group, or a system composed of multiple lenses (i.e., a group or lens assembly). It's also understandable that in the process of zooming by moving the corresponding lens group, the zoom lens is at its shortest focal length (wide-angle end) and at its longest focal length (telephoto end). At the short and long focal lengths, the zoom lens has different focal lengths and optical powers, as well as different lengths or shapes.

[0076] In this embodiment of the invention, the focusing lens group 100, the aperture stop, the zoom lens group 200, and the fixed lens group 300 can be housed in a single lens barrel. The aperture stop is fixed in position within the lens barrel, meaning its position relative to the image plane remains consistent across different focal lengths, and its aperture diameter is the same across all focal lengths. The focusing lens group 100 and the zoom lens group 200 can reciprocate along the optical axis within the lens barrel to switch between the short and long focal lengths of the zoom lens. The zoom lens group 200 adjusts the focal length of the lens by moving, while the focusing lens group 100 compensates for aberrations caused during the movement of the zoom lens group 200, ensuring clear imaging. Furthermore, using a negative optical power focusing lens group 100 at the front of the entire optical system can diverge light, increasing the entrance pupil diameter and light transmission. The zoom lens group 200 behind the aperture stop and the fixed lens group 300 work in conjunction with the focusing lens group 100 in front of the aperture stop to stabilize the imaging quality of the optical system. Furthermore, the number of lenses and optical power in each lens group in this embodiment are set to optimize the imaging quality during zooming and meet the requirements for clear imaging. At the same time, by using the movable zoom lens group 200 to adapt to the fixed aperture with the same diameter, not only can the aperture diameter be reduced and the lens size be reduced, which helps to reduce the size of the lens, but also a smaller F number can be achieved in each focal length, that is, a larger aperture can be achieved, to meet the needs for a large aperture in different focal lengths.

[0077] In one specific embodiment, optionally, in the focusing lens group 100, the first lens 1 is a spherical lens, and the second lens 2 and the third lens 3 are aspherical lenses; in the zoom lens group 200, the sixth lens 6, the seventh lens 7, and the eighth lens 8 are all spherical lenses, and the fourth lens 4, the fifth lens 5, and the ninth lens 9 are all aspherical lenses; in the fixed lens group 300, the tenth lens 10 is a spherical lens, and the eleventh lens is an aspherical lens.

[0078] Specifically, during the zooming process of the entire optical system, the focusing lens group 100 is responsible for focusing the optical system as the focal length changes. The second lens 2 and the third lens 3 use aspherical lenses, which can effectively correct chromatic aberration and preliminary aberrations of the incoming light, significantly reducing the aberration pressure on other lens groups at different focal lengths. This achieves the requirement of clear focusing across the entire focal length range. Simultaneously, it can converge light, allowing it to smoothly enter the aperture, ensuring the aperture diameter of the optical system, increasing the amount of light entering the optical system, increasing the lens F-number, and improving the brightness and image quality of the image. The zoom lens group 200 is responsible for changing the focal length of the optical system. Using aspherical lenses as the fourth lens 4, fifth lens 5, and ninth lens 9, it can further correct the advanced aberrations and chromatic aberrations remaining in the focusing lens group 100, optimize the field curvature at different image heights, and allow light to enter the target surface stably and smoothly, improving the overall image quality of the optical system. The fixed lens group 300 uses one spherical lens and one aspherical lens to control the exit angle of the light rays, which is convenient for matching with large target surface chips. This ensures that the lens is confocal and has high image quality in the 436nm-850nm wavelength range, meeting the needs of use under different conditions.

[0079] In one specific embodiment, optionally, in the focusing lens group 100, the first lens 1 is a convex-concave lens, the second lens 2 is a concave-concave lens, and the third lens 3 is a convex-concave lens or a convex-convex lens; in the zoom lens group 200, the fourth lens 4 is a convex-convex lens, the fifth lens 5 is a convex-concave lens, the sixth lens 6 is a convex-convex lens, the seventh lens 7 is a concave-concave lens, the eighth lens 8 is a convex-concave lens, and the ninth lens 9 is a convex-concave lens or a convex-convex lens; in the fixed lens group 300, the tenth lens 10 is a concave-concave lens, and the eleventh lens is a convex-convex lens.

[0080] In one specific embodiment, optionally, the zoom optics satisfy the following conditions: -3.013≤FG1 / FW≤-2.791; 2.650≤FG2 / FW≤2.759; -27.265≤FG3 / FW≤-13.112; FT / FW=3.531; where FG1, FG2, and FG3 are the focal lengths of the focusing lens group 100, the zoom lens group 200, and the fixed lens group 300, respectively, FW is the focal length at the short focal length end of the zoom lens, and FT is the focal length at the long focal length end of the zoom lens.

[0081] In this embodiment, by limiting the specific ratio of the focal length of each lens to the overall system, a reasonable combination of optical power can be achieved, which can allow light to pass through the lens more smoothly and largely correct the impact of advanced aberrations on image quality.

[0082] In one specific embodiment, optionally, the zoom optics satisfies the following condition: 1.510≤F4 / FG2≤2.757; where F4 is the focal length of the fourth lens 4 and FG2 is the focal length of the zoom lens group 200.

[0083] In this embodiment, by controlling the ratio of the focal length of the fourth lens 4 to the focal length of the zoom lens group 200, the contribution of the fourth lens 4 to the entire zoom lens group 200 optical power can be increased. Simultaneously, by setting the fourth lens 4 as an aspherical lens, aspherical lenses have advantages over spherical lenses in correcting advanced aberrations and chromatic aberration. Furthermore, since the fourth lens 4 is immediately adjacent to the aperture stop, it can significantly and effectively correct aberrations in the light rays emitted from the aperture stop at different focal lengths, thereby improving the system's imaging quality.

[0084] In one specific embodiment, optionally, the seventh lens 7 and the eighth lens 8 are cemented together to form a cemented doublet lens group, or the sixth lens 6, the seventh lens 7 and the eighth lens 8 are cemented together to form a cemented triplet lens group.

[0085] In this embodiment, by setting aspherical lenses and cemented lenses in the zoom lens group 200, they can work together to correct higher aberrations and chromatic aberrations of light passing through the aperture at different focal lengths. The lens group at the front end of the aperture can stabilize the imaging quality of the optical system.

[0086] In one specific embodiment, optionally, the sixth lens 6, the seventh lens 7, and the eighth lens 8 satisfy the following conditions: 1.437≤nd6≤1.713; 53.94≤vd6≤95.12; 1.604≤nd7≤2.04; 24.08≤vd7≤28.24; 1.437≤nd8≤1.713; 53.94≤vd8≤95.12; wherein nd6, nd7, and nd8 are the refractive indices of the sixth lens 6, the seventh lens 7, and the eighth lens 8, respectively, and vd6, vd7, and vd8 are the Abbe numbers of the sixth lens 6, the seventh lens 7, and the eighth lens 8, respectively.

[0087] In this embodiment, the fourth lens 4 and the fifth lens 5 of the zoom lens group 200 are plastic aspherical lenses. Plastic lenses offer limited material options and have limited ability to correct chromatic aberration. In contrast, the sixth lens 6, the seventh lens 7, and the eighth lens 8 utilize combinations of low-refractive-index high Abbe, high-refractive-index low Abbe, and low-refractive-index high Abbe lenses, respectively, representing significant differences in material properties. This combination effectively corrects chromatic aberration and eliminates higher-order aberrations in the optical system. Furthermore, the sixth lens 6, the seventh lens 7, and the eighth lens 8 can form a cemented triplet lens group or a cemented doublet lens group plus a single lens element. The cemented lens further corrects chromatic aberration and improves the imaging quality of the optical system.

[0088] In addition, since glass lenses are not sensitive to temperature, using glass lenses for spherical lenses can ensure more consistent lens performance under different temperature conditions, with stable performance at high and low temperatures, thus improving the environmental adaptability of zoom lenses. Compared with plastic aspherical lenses, there is also a wider range of choices, allowing for more diverse structural options and enhancing the lens's market competitiveness.

[0089] In one specific embodiment, optionally, the zoom lens satisfies the following conditions: WFNO≤1.6; TFNO≤3.3; where WFNO is the aperture number at the short focal length end of the zoom lens, and TFNO is the aperture number at the long focal length end of the zoom lens.

[0090] In one specific embodiment, optionally, the zoom optics satisfies the following condition: 2.724≤S1 / S2≤2.943; where S1 is the maximum movable distance of the focusing lens group 100 and S2 is the maximum movable distance of the zoom lens group 200.

[0091] In this embodiment, by limiting the moving distance of the focusing lens group 100 and the zoom lens group 200, the volume and range of motion of the focusing lens group 100 can be minimized to the greatest extent, thereby greatly reducing the size of the lens.

[0092] In one specific embodiment, optionally, the zoom lens satisfies the following condition: 3.054≤TTL / S1≤3.221; where TTL is the total optical length of the zoom lens, and S1 is the maximum movable distance of the focusing lens group 100.

[0093] In this embodiment, by limiting the focusing lens group 100 and the total length of the lens, the space of the entire optical system can be compressed, ensuring that focusing stability and imaging quality are met under different focal length requirements while maintaining a small lens size.

[0094] Based on the same concept, this utility model provides three different specific embodiments, and their optical power relationship and related physical optical parameter design ranges are shown in Table 1:

[0095] Table 1 shows the relationship between the optical power of each lens and the design values ​​of related physical and optical parameters in the three embodiments.

[0096]

[0097] like Figure 1 and Figure 2As shown, the zoom lens of this embodiment includes a focusing lens group 100, a zoom lens group 200, and a fixed lens group 300 arranged sequentially along the optical axis from the object plane to the image plane; a planar glass CG is also provided along the object plane to the image plane; the planar glass CG is located on the image-side surface of the eleventh lens, and the planar glass CG can protect the photosensitive chip in the imaging sensor, wherein the imaging chip is used to convert the light signal collected by the zoom lens into an electrical signal, thereby ensuring the imaging effect of the zoom lens. In the zoom lens provided in this embodiment, the zoom lens group 200 and the focusing lens group 100 can reciprocate along the optical axis in the lens barrel. Through the joint movement of the zoom lens group 200 and the focusing lens group 100, the focal length of the zoom lens can achieve continuous change from short focal length to long focal length, ensuring high image quality at all focal points. Specifically, in this embodiment, the third lens 3 is a convex-convex lens, the ninth lens 9 is a convex-concave lens, and the seventh lens 7 and the eighth lens 8 are cemented together to form a cemented doublet lens group. Figure 1 and Figure 2 The parameter design values ​​of each lens in the zoom lens of Embodiment 1 are shown in Table 2:

[0098] Table 2. Design values ​​for each lens in the zoom lens in Example 1

[0099]

[0100] The surface numbers in Table 2 are assigned according to the surface sequence of each lens. "STO" represents the aperture stop of the lens. The radius of curvature represents the degree of curvature of the corresponding lens surface. A positive value indicates that the surface bends towards the image plane, and a negative value indicates that the surface bends towards the object plane. "INF" indicates that the surface is flat and the radius of curvature is infinite. The thickness represents the central axial distance between the current surface and the next surface. The refractive index represents the ability of the material between the current surface and the next surface to deflect light. A blank space indicates that the current position is air and the refractive index is 1. The zoom interval in Table 3 is the different interval values ​​of the lens at the short focal length and the long focal length.

[0101] Table 3. Zoom intervals of the zoom lens at the short focal length and long focal length ends in Example 1

[0102]

[0103] The aspherical conic coefficients can be defined using the following aspherical formulas, but are not limited to the following representations:

[0104] ;

[0105] Where Z is the axial distance from the vertex of the surface at a position perpendicular to the optical axis and at a height of r along the optical axis; c represents the curvature at the vertex of the aspherical surface; , , , , , These are the higher-order aspheric coefficients corresponding to the fourth, sixth, eighth, tenth, twelfth, and fourteenth orders of aspheric surfaces. These are combined to form higher-order terms for the corresponding aspherical surfaces. The coefficients of the even-order terms for each aspherical surface in Example 1 above are shown in Table 4:

[0106] Table 4 Aspherical parameters of each lens in the zoom lens in Example 1

[0107]

[0108] Where -3.519792821702E-03 represents the coefficient for surface number 3. -3.519792821702×10 -3 And so on.

[0109] The parameters of the zoom lens in this embodiment are shown in Table 5:

[0110] Table 5. Parameter specifications of the zoom lens in Example 1

[0111]

[0112] Figure 3 The transverse chromatic aberration curve of the zoom lens at the short focal length end provided in Embodiment 1 of this utility model. Figure 4 This is the transverse chromatic aberration curve at the telephoto end of the zoom lens provided in Embodiment 1 of this utility model. The vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, and the vertex in the transverse direction represents the maximum pupil radius. The dominant wavelength is 546nm, and the horizontal direction represents the offset relative to the dominant wavelength, in micrometers (µm). Figure 3 , Figure 4 It can be seen that the chromatic aberration along the vertical axis is controlled within a small range for different wavelengths, indicating that the chromatic aberration along the vertical axis of the zoom lens is well controlled at different focal lengths, which can meet the application requirements under normal conditions.

[0113] Figure 5 This is the ray fan pattern of the zoom lens at the short focal length end provided in Embodiment 1 of this utility model. Figure 6This invention provides a ray fan plot of a zoom lens at the telephoto end, as shown in Embodiment 1 of this utility model. The ray fan plot is a commonly used evaluation method by optical designers. In a single plot, the horizontal axis represents the normalized beam aperture, and the vertical axis represents the transverse aberration. Ideally, each curve should completely coincide with the horizontal axis, at which point all rays in the field of view are focused at the same point on the image plane. The vertical axis in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. The ray fan plot can not only reflect monochromatic aberrations at different wavelengths but also the magnitude of transverse chromatic aberration. Figure 5 , Figure 6 It can be seen that the wavelengths of this zoom lens closely approximate the horizontal axis at different focal lengths and fields of view, indicating that the transverse aberrations of each wavelength are well corrected. Furthermore, the curves for each color do not show significant dispersion, indicating that this zoom lens also has good chromatic aberration correction, meeting the usage requirements of this zoom lens.

[0114] Figure 7 The MTF curve of the zoom lens at the short focal length end provided in Embodiment 1 of this utility model. Figure 8 The MTF curve of the zoom lens at the telephoto end provided in Embodiment 1 of this utility model is shown in the coordinate system on the left side of both figures. The horizontal axis represents the magnitude of the MTF frequency, in lp / mm; the vertical axis represents the MTF value, which is unitless; where T represents meridion and S represents arc loss. Figure 7 and Figure 8 It can be seen that the lens provided in this embodiment has MTF values ​​at different frequencies, ranging from light with wavelengths of 436nm to 656nm. As shown in the figure, the zoom lens has an MTF of >0.5 at a frequency of 80lp / mm at different focal lengths, which meets the high image quality requirements at different focal lengths.

[0115] Figure 9 This is the axial aberration curve of the zoom lens at the short focal length end provided in Embodiment 1 of this utility model. Figure 10 This is the axial aberration curve at the telephoto end of the zoom lens provided in Embodiment 1 of this utility model. The vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, and the vertex in the perpendicular direction represents the maximum pupil radius. The dominant wavelength is 546nm, and the horizontal direction represents the offset relative to the dominant wavelength, in millimeters (mm). Figure 9 , Figure 10 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 transverse chromatic aberration of the zoom lens at different focal lengths is well controlled and meets the usage requirements.

[0116] Figure 11 This is a schematic diagram of the structure of a zoom lens at the short focal length end according to Embodiment 2 of this utility model. Figure 12This is a schematic diagram of the structure of a zoom lens at the telephoto end according to Embodiment 2 of this utility model, for reference. Figure 11 and Figure 12 The zoom lens of this embodiment includes a focusing lens group 100, a zoom lens group 200, and a fixed lens group 300 arranged sequentially along the optical axis from the object plane to the image plane. A planar glass CG is also disposed along the object plane to the image plane. The planar glass CG is located on the image-side surface of the eleventh lens. The planar glass CG protects the photosensitive chip in the imaging sensor, which converts the light signals collected by the zoom lens into electrical signals, thereby ensuring the imaging effect of the zoom lens. In the zoom lens provided in this embodiment, the zoom lens group 200 and the focusing lens group 100 can reciprocate along the optical axis within the lens barrel. The combined movement of the zoom lens group 200 and the focusing lens group 100 allows for continuous changes in the focal length of the zoom lens from short focal length to long focal length, ensuring high image quality at all focal points. Specifically, in this embodiment, the third lens 3 is a convex-concave lens, the ninth lens 9 is a convex-convex lens, and the seventh lens 7 and the eighth lens 8 are cemented together to form a cemented doublet lens group. Figure 11 and Figure 12 The parameter design values ​​of each lens in the zoom lens of Embodiment 2 are shown in Table 6:

[0117] Table 6. Design values ​​for each lens in the zoom lens in Example 2

[0118]

[0119] The surface numbers in Table 6 are assigned according to the surface sequence of each lens. "STO" represents the aperture stop of the lens. The radius of curvature represents the curvature of the corresponding lens surface. A positive value indicates that the surface bends towards the image plane, and a negative value indicates that the surface bends towards the object plane. "INF" indicates that the surface is flat and the radius of curvature is infinite. The thickness represents the central axial distance between the current surface and the next surface. The refractive index represents the ability of the material between the current surface and the next surface to deflect light. A blank space indicates that the current position is air and the refractive index is 1. The zoom interval in Table 7 is the different interval values ​​of the lens at the short focal length and the long focal length.

[0120] Table 7. Zoom intervals of the zoom lens at the short focal length and long focal length ends in Example 2

[0121]

[0122] The aspherical conic coefficients can be defined using the following aspherical formulas, but are not limited to the following representations:

[0123] ;

[0124] Where Z is the axial distance from the vertex of the surface at a position perpendicular to the optical axis and at a height of r along the optical axis; c represents the curvature at the vertex of the aspherical surface; , , , , , These are the higher-order aspheric coefficients corresponding to the fourth, sixth, eighth, tenth, twelfth, and fourteenth orders of aspheric surfaces. These are combined to form higher-order terms for the corresponding aspherical surfaces. The coefficients of the even-order terms for each aspherical surface in Example 2 above are shown in Table 8:

[0125] Table 8 Aspherical parameters of each lens in the zoom lens in Example 2

[0126]

[0127] Where -2.576235504069E-03 represents the coefficient for surface number 3. -2.576235504069×10 -3 And so on.

[0128] The parameters of the zoom lens in this embodiment two are shown in Table 9:

[0129] Table 9. Parameter specifications of the zoom lens in Example 2

[0130]

[0131] Figure 13 This is the transverse chromatic aberration curve of the zoom lens at the short focal length end provided in Embodiment 2 of this utility model. Figure 14 This is the transverse chromatic aberration curve at the telephoto end of the zoom lens provided in Embodiment 2 of this utility model. The vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, and the vertex in the transverse direction represents the maximum pupil radius. The dominant wavelength is 546nm, and the horizontal direction represents the offset relative to the dominant wavelength, in micrometers (µm). Figure 13 , Figure 14 It can be seen that the chromatic aberration along the vertical axis is controlled within a small range for different wavelengths, indicating that the chromatic aberration along the vertical axis of the zoom lens is well controlled at different focal lengths, which can meet the application requirements under normal conditions.

[0132] Figure 15 This is the light fan pattern of the zoom lens at the short focal length end provided in Embodiment 2 of this utility model. Figure 16This is a ray fan plot of a zoom lens at the telephoto end, provided in Embodiment 2 of this utility model. The ray fan plot is a commonly used evaluation method by optical designers. In a single plot, the horizontal axis represents the normalized beam aperture, and the vertical axis represents the transverse aberration. Ideally, each curve should completely coincide with the horizontal axis, at which point all rays in the field of view are focused at the same point on the image plane. The vertical axis in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. The ray fan plot can not only reflect monochromatic aberrations of different wavelengths but also the magnitude of transverse chromatic aberration. Figure 15 , Figure 16 It can be seen that the wavelengths of this zoom lens closely approximate the horizontal axis at different focal lengths and fields of view, indicating that the transverse aberrations of each wavelength are well corrected. Furthermore, the curves for each color do not show significant dispersion, indicating that this zoom lens also has good chromatic aberration correction, meeting the usage requirements of this zoom lens.

[0133] Figure 17 This is the MTF curve of the zoom lens at the short focal length end provided in Embodiment 2 of this utility model. Figure 18 This is the MTF curve of the zoom lens at the telephoto end provided in Embodiment 2 of this utility model. In the coordinate system on the left side of both figures, the horizontal axis represents the magnitude of the MTF frequency, in lp / mm; the vertical axis represents the MTF value, without units; where T represents meridion and S represents arc loss; from Figure 17 and Figure 18 It can be seen that the lens provided in this embodiment has MTF values ​​at different frequencies, ranging from light with wavelengths of 436nm to 656nm. As shown in the figure, the zoom lens has an MTF of >0.5 at a frequency of 80lp / mm at different focal lengths, which meets the high image quality requirements at different focal lengths.

[0134] Figure 19 This is the axial aberration curve of the zoom lens at the short focal length end provided in Embodiment 2 of this utility model. Figure 20 This is the axial aberration curve at the telephoto end of the zoom lens provided in Embodiment 2 of this utility model. The vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, and the vertex in the perpendicular direction represents the maximum pupil radius. The dominant wavelength is 546nm, and the horizontal direction represents the offset relative to the dominant wavelength, in millimeters (mm). Figure 19 , Figure 20 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 transverse chromatic aberration of the zoom lens at different focal lengths is well controlled and meets the usage requirements.

[0135] Figure 21 This is a schematic diagram of the structure of a zoom lens at the short focal length end according to Embodiment 3 of this utility model. Figure 22This is a schematic diagram of the structure of a zoom lens at the telephoto end according to Embodiment 3 of this utility model. (Refer to...) Figure 21 and Figure 22 The zoom lens of this embodiment includes a focusing lens group 100, a zoom lens group 200, and a fixed lens group 300 arranged sequentially along the optical axis from the object plane to the image plane. A planar glass CG is also provided along the object plane to the image plane. The planar glass CG is located on the image-side surface of the eleventh lens. The planar glass CG protects the photosensitive chip in the imaging sensor, which converts the light signals collected by the zoom lens into electrical signals, thereby ensuring the imaging effect of the zoom lens. In the zoom lens provided in this embodiment, the zoom lens group 200 and the focusing lens group 100 can reciprocate along the optical axis within the lens barrel. The combined movement of the zoom lens group 200 and the focusing lens group 100 allows for continuous changes in the focal length of the zoom lens from short focal length to long focal length, ensuring high image quality at all focal points. Specifically, in this embodiment, the third lens 3 is a convex-convex lens, the ninth lens 9 is a convex-convex lens, and the sixth lens 6, the seventh lens 7, and the eighth lens 8 are cemented together to form a cemented triplet lens group. Figure 21 and Figure 22 The parameter design values ​​of each lens in the zoom lens of Embodiment 3 are shown in Table 10:

[0136] Table 10. Design values ​​for each lens in the zoom lens of Example 3

[0137]

[0138] The surface numbers in Table 10 are assigned according to the surface sequence of each lens. "STO" represents the aperture stop of the lens. The radius of curvature represents the curvature of the corresponding lens surface. A positive value indicates that the surface bends towards the image plane, and a negative value indicates that the surface bends towards the object plane. "INF" indicates that the surface is flat and the radius of curvature is infinite. The thickness represents the central axial distance between the current surface and the next surface. The refractive index represents the ability of the material between the current surface and the next surface to deflect light. A blank space indicates that the current position is air and the refractive index is 1. The zoom interval in Table 11 is the different interval values ​​of the lens at the short focal length and the long focal length.

[0139] Table 11 Zoom intervals of the zoom lens at the short focal length and long focal length ends in Example 3

[0140]

[0141] The aspherical conic coefficients can be defined using the following aspherical formulas, but are not limited to the following representations:

[0142] ;

[0143] Where Z is the axial distance from the vertex of the surface at a position perpendicular to the optical axis and at a height of r along the optical axis; c represents the curvature at the vertex of the aspherical surface; , , , , , These are the higher-order aspheric coefficients corresponding to the fourth, sixth, eighth, tenth, twelfth, and fourteenth orders of aspheric surfaces. These are combined to form higher-order terms for the corresponding aspherical surfaces. The coefficients of the even-order terms for each aspherical surface in Example 3 above are shown in Table 12:

[0144] Table 12 Aspherical parameters of each lens in the zoom lens in Example 3

[0145]

[0146] Where -2.288956974890E-03 represents the coefficient for surface number 3. -2.288956974890×10 -3 And so on.

[0147] The parameters of the zoom lens in this embodiment three are shown in Table 13:

[0148] Table 13 Parameter Specifications of the Zoom Lens in Example 3

[0149]

[0150] Figure 23 This is the transverse chromatic aberration curve of the zoom lens at the short focal length end provided in Embodiment 3 of this utility model. Figure 24 This is the transverse chromatic aberration curve at the telephoto end of the zoom lens provided in Embodiment 3 of this utility model. The vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, and the vertex in the transverse direction represents the maximum pupil radius. The dominant wavelength is 546nm, and the horizontal direction represents the offset relative to the dominant wavelength, in micrometers (µm). Figure 23 , Figure 24 It can be seen that the chromatic aberration along the vertical axis is controlled within a small range for different wavelengths, indicating that the chromatic aberration along the vertical axis of the zoom lens is well controlled at different focal lengths, which can meet the application requirements under normal conditions.

[0151] Figure 25 This is the light fan pattern of the zoom lens at the short focal length end provided in Embodiment 3 of this utility model. Figure 26This is a ray fan plot of a zoom lens at the telephoto end, provided in Embodiment 3 of this utility model. The ray fan plot is a commonly used evaluation method by optical designers. In a single plot, the horizontal axis represents the normalized beam aperture, and the vertical axis represents the transverse aberration. Ideally, each curve should completely coincide with the horizontal axis, at which point all rays in the field of view are focused at the same point on the image plane. The vertical axis in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. The ray fan plot can not only reflect monochromatic aberrations of different wavelengths but also the magnitude of transverse chromatic aberration. Figure 25 , Figure 26 It can be seen that the wavelengths of this zoom lens closely approximate the horizontal axis at different focal lengths and fields of view, indicating that the transverse aberrations of each wavelength are well corrected. Furthermore, the curves for each color do not show significant dispersion, indicating that this zoom lens also has good chromatic aberration correction, meeting the usage requirements of this zoom lens.

[0152] Figure 27 This is the MTF curve of the zoom lens at the short focal length end provided in Embodiment 3 of this utility model. Figure 28 The MTF curve of the zoom lens at the telephoto end provided in Embodiment 3 of this utility model is shown in the coordinate system on the left side of both figures. The horizontal axis represents the magnitude of the MTF frequency, in lp / mm; the vertical axis represents the MTF value, without units; where T represents meridion and S represents arc loss. Figure 27 and Figure 28 It can be seen that the lens provided in this embodiment has MTF values ​​at different frequencies, ranging from light with wavelengths of 436nm to 656nm. As shown in the figure, the zoom lens has an MTF of >0.5 at a frequency of 80lp / mm at different focal lengths, which meets the high image quality requirements at different focal lengths.

[0153] Figure 29 This is the axial aberration curve of the zoom lens at the short focal length end provided in Embodiment 3 of this utility model. Figure 30 This is the axial aberration curve at the telephoto end of the zoom lens provided in Embodiment 3 of this utility model. The vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, and the vertex in the perpendicular direction represents the maximum pupil radius. The dominant wavelength is 546nm, and the horizontal direction represents the offset relative to the dominant wavelength, in millimeters (mm). Figure 29 , Figure 30 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 transverse chromatic aberration of the zoom lens at different focal lengths is well controlled and meets the usage requirements.

[0154] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A zoom lens, characterized in that, It includes a focusing lens group with negative optical power, an aperture, a zoom lens group with positive optical power, and a fixed lens group with negative optical power, arranged sequentially from the object side to the image side along the optical axis. The focusing lens group includes a first lens with negative optical power, a second lens with negative optical power, and a third lens with positive optical power; The zoom lens group includes a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with positive optical power, a seventh lens with negative optical power, an eighth lens with positive optical power, and a ninth lens with positive optical power. The fixed lens group includes a tenth lens with negative optical power and an eleventh lens with positive optical power; The fixed lens group is fixedly arranged, while the focusing lens group and the zoom lens group are movable. When the zoom lens changes between the short focal length end and the long focal length end, the focusing lens group and the zoom lens group move synchronously and cooperatively along the optical axis.

2. The zoom lens according to claim 1, characterized in that, In the focusing lens group, the first lens is a spherical lens, and the second and third lenses are aspherical lenses; In the zoom lens group, the sixth lens, the seventh lens, and the eighth lens are all spherical lenses, while the fourth lens, the fifth lens, and the ninth lens are all aspherical lenses. In the fixed lens group, the tenth lens is a spherical lens, and the eleventh lens is an aspherical lens.

3. The zoom lens according to claim 1, characterized in that, In the focusing lens group, the first lens is a convex-concave lens, the second lens is a concave-concave lens, and the third lens is a convex-concave lens or a convex-convex lens; In the zoom lens group, the fourth lens is a convex-convex lens, the fifth lens is a convex-concave lens, the sixth lens is a convex-convex lens, the seventh lens is a concave-concave lens, the eighth lens is a convex-concave lens, and the ninth lens is a convex-concave lens or a convex-convex lens. In the fixed lens group, the tenth lens is a concave-concave lens, and the eleventh lens is a convex-convex lens.

4. The zoom lens according to claim 1, characterized in that, The zoom optics satisfy the following conditions: -3.013≤FG1 / FW≤-2.791; 2.650≤FG2 / FW≤2.759; -27.265≤FG3 / FW≤-13.112; FT / FW = 3.531; Wherein, FG1, FG2, and FG3 are the focal lengths of the focusing lens group, the zoom lens group, and the fixed lens group, respectively; FW is the focal length at the short focal length end of the zoom lens; and FT is the focal length at the long focal length end of the zoom lens.

5. The zoom lens according to claim 1, characterized in that, The zoom optics satisfy the following condition: 1.510≤F4 / FG2≤2.757; Wherein, F4 is the focal length of the fourth lens, and FG2 is the focal length of the zoom lens group.

6. The zoom lens according to claim 1, characterized in that, The seventh lens and the eighth lens are cemented together to form a cemented doublet lens group, or the sixth lens, the seventh lens and the eighth lens are cemented together to form a cemented triplet lens group.

7. The zoom lens according to claim 1, characterized in that, The sixth lens, the seventh lens, and the eighth lens satisfy the following conditions: 1.437≤nd6≤1.713; 53.94≤vd6≤95.12; 1.604≤nd7≤2.04; 24.08≤vd7≤28.24; 1.437≤nd8≤1.713;53.94≤vd8≤95.12; Wherein, nd6, nd7, and nd8 are the refractive indices of the sixth, seventh, and eighth lenses, respectively, and vd6, vd7, and vd8 are the Abbe numbers of the sixth, seventh, and eighth lenses, respectively.

8. The zoom lens according to claim 1, characterized in that, The zoom lens meets the following conditions: WFNO≤1.6; TFNO≤3.3; Wherein, WFNO is the aperture number at the short focal length end of the zoom lens, and TFNO is the aperture number at the long focal length end of the zoom lens.

9. The zoom lens according to claim 1, characterized in that, The zoom optics satisfy the following condition: 2.724≤S1 / S2≤2.943; Wherein, S1 is the maximum movable distance of the focusing lens group, and S2 is the maximum movable distance of the zoom lens group.

10. The zoom lens according to claim 1, characterized in that, The zoom lens satisfies the following condition: 3.054≤TTL / S1≤3.221; Wherein, TTL is the total optical length of the zoom lens, and S1 is the maximum movable distance of the focusing lens group.

Images