Lens

Abstract

The lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens which are sequentially arranged from an object plane to an image plane along an optical axis, the first lens has negative focal power, the second lens has negative focal power, the third lens has positive focal power, the fourth lens has positive focal power, the fifth lens has negative focal power, the sixth lens has positive focal power, and the seventh lens has negative focal power. The fifth lens has positive focal power, the sixth lens has negative focal power, and the seventh lens has positive focal power. According to the lens provided by the embodiment of the utility model, only seven lenses are adopted, and the focal power and the surface type of each lens are reasonably matched, so that the total optical length of the lens can reach 23.4 mm and below, the field angle FOV can reach 136 degrees, the image surface diameter can reach 7.5 mm, the aperture number F can reach 1.8, aberration can be well corrected, enough good image quality is ensured, and the lens is suitable for large-scale popularization and application. The lens which is high in resolution, compact in structure, large in field angle, large in target surface and large in aperture is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of optics, in particular to a lens. Background Art

[0002] Automotive intelligence is one of the important directions for future industry development. As the eyes of automotive intelligence, on-board cameras provide content and services to drivers during driving, improving driving safety, comfort and convenience.

[0003] As an important component of vehicle lenses, vehicle rearview cameras pay great attention to optical performance and have been progressing towards high precision, high adaptability, miniaturization and intelligence.

[0004] Under the current design trend of miniaturization, the field of view angle, target surface and aperture cannot be taken into account at the same time, and the overall aberration of the lens is large, which is not conducive to achieving high-quality imaging. Utility Model Content

[0005] The utility model provides a lens, which can realize a lens having high resolution, compact structure, large field angle, large target surface and large aperture.

[0006] The utility model provides a lens, comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged in sequence along an optical axis from an object plane to an image plane;

[0007] The first lens has negative optical power, its object side surface is convex, and its image side surface is concave;

[0008] The second lens has negative optical power, its object side surface is concave, and its image side surface is convex;

[0009] The third lens has positive refractive power, its object side surface is convex, and its image side surface is flat or concave;

[0010] The fourth lens has positive refractive power, its object side surface is concave, and its image side surface is convex;

[0011] The fifth lens has positive refractive power, and its object-side surface is convex, and its image-side surface is convex;

[0012] The sixth lens has negative optical power, its object side surface is concave, and its image side surface is convex;

[0013] The seventh lens has positive refractive power, an object-side surface thereof is convex, and an image-side surface thereof is concave or convex.

[0014] Optionally, the fifth lens and the sixth lens form a first cemented lens group.

[0015] Optionally, a thickness of the fifth lens is L5, a thickness of the sixth lens is L6, and L5+L6≤3mm.

[0016] Optionally, a refractive index of the first lens is n1, and an Abbe number is v1; a refractive index of the second lens is n2, and an Abbe number is v2; a refractive index of the third lens is n3, and an Abbe number is v3; a refractive index of the fourth lens is n4, and an Abbe number is v4; a refractive index of the fifth lens is n5, and an Abbe number is v5; a refractive index of the sixth lens is n6, and an Abbe number is v6; and a refractive index of the seventh lens is n7, and an Abbe number is v7.

[0017] 1.75≤n1≤2.00; 25.89≤v1≤51.01;

[0018] 1.62≤n2≤2.10; 29.00≤v2≤71.00;

[0019] 1.80≤n3≤2.10; 25.29≤v3≤48.48;

[0020] 1.60≤n4≤1.90; 39.00≤v4≤61.00;

[0021] 1.43≤n5≤1.69; 47.51≤v5≤95.00;

[0022] 1.83≤n6≤2.10; 15.00≤v6≤25.94;

[0023] 1.61≤n7≤2.10; 22.63≤v7≤61.01.

[0024] Optionally, an optical back focal length of the lens is BFL, and an overall optical length of the lens is TTL, and BFL / TTL≥0.16.

[0025] Optionally, a maximum field of view of the lens is FOV, and an overall optical length of the lens is TTL, and FOV / TTL≥5.

[0026] Optionally, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are all glass spherical lenses.

[0027] Optionally, the lens further comprises a diaphragm.

[0028] The diaphragm is located in an optical path between the third lens and the fourth lens.

[0029] Alternatively, the diaphragm is located in an optical path between the second lens and the third lens.

[0030] Alternatively, the aperture is located in the optical path between the fourth lens and the fifth lens.

[0031] Optionally, the total optical length of the lens is TTL, and TTL≤23.4mm.

[0032] Optionally, the maximum field of view of the lens is FOV, and FOV is ≥136°.

[0033] The lens provided by the embodiment of the present invention uses only seven lenses. By reasonably matching the optical power and surface shape of each lens, the total optical length of the lens is reduced to 23.4 mm or less, the field of view (FOV) can reach 136°, the image plane diameter can reach 7.5 mm, the aperture number F reaches 1.8, and it can well correct aberrations to ensure sufficiently good image quality and stable high and low temperature resolution, thus realizing a lens that can take into account high resolution, compact structure, large field of view, large target surface, and large aperture.

[0034] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 A schematic structural diagram of a lens provided in an embodiment of the present utility model;

[0037] Figure 2 A schematic structural diagram of another lens provided in an embodiment of the present utility model;

[0038] Figure 3 A schematic structural diagram of another lens provided by an embodiment of the present utility model;

[0039] Figure 4 This is a spherical aberration curve diagram of the lens provided in Example 1 of the present utility model;

[0040] Figure 5 This is a spherical aberration curve diagram of the lens provided in Example 2 of the present utility model;

[0041] Figure 6 This is a spherical aberration curve diagram of the lens provided in Example 3 of the present utility model. DETAILED DESCRIPTION

[0042] In order to help those skilled in the art better understand the present invention, the following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0043] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0044] Figure 1 This is a structural diagram of a lens provided by an embodiment of the utility model. Figure 2 This is a schematic diagram of the structure of another lens provided by an embodiment of the utility model. Figure 3 A structural diagram of another lens provided in an embodiment of the present utility model is shown as follows: Figure 1-Figure 3 As shown, the lens provided by the embodiment of the present invention includes a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, a fifth lens 15, a sixth lens 16, and a seventh lens 17, which are arranged in sequence along the optical axis from the object plane to the image plane. The first lens 11 has negative optical power, its object side surface is convex, and its image side surface is concave; the second lens 12 has negative optical power, its object side surface is concave, and its image side surface is convex; the third lens 13 has positive optical power, its object side surface is convex, and its image side surface is flat or concave; the fourth lens 14 has positive optical power, its object side surface is concave, and its image side surface is convex; the fifth lens 15 has positive optical power, its object side surface is convex, and its image side surface is convex; the sixth lens 16 has negative optical power, its object side surface is concave, and its image side surface is convex; the seventh lens 17 has positive optical power, its object side surface is convex, and its image side surface is either concave or convex.

[0045] Specifically, the focal length is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam, and it characterizes the ability of an optical system to deflect light. The larger the absolute value of the focal length, the stronger the ability to bend light, and the smaller the absolute value of the focal length, the weaker the ability to bend light. When the focal length is a positive number, the refraction of light is convergent; when the focal length is a negative number, the refraction of light is divergent. The focal length can be used to characterize a refractive surface of a lens (i.e., a surface of a lens), a single lens, or a system formed by multiple lenses (i.e., a lens group).

[0046] In the lens provided in this embodiment, each lens can be fixed to a lens barrel ( Figure 1 (not shown), but is not limited thereto.

[0047] Among them, the first lens 11 and the second lens 12 have negative optical power, which diverges the light at the front end of the lens, allowing more light to enter the subsequent lens at a larger angle, which is conducive to achieving a large field of view (FOV) and thus capturing a wider scene. It can be suitable for panoramic photography or surveillance cameras.

[0048] Furthermore, the first lens 11 is a meniscus lens with a convex object-side surface and a concave image-side surface. The shape of the first lens 11 adopts a convex front and concave back design, which can effectively control the incident angle of light without increasing the diameter of the lens. This helps to reduce the physical size of the first lens L1, thereby reducing the effective aperture of the front end of the lens, making the entire lens more compact and lightweight.

[0049] The second lens 12 is a meniscus lens with a concave object-side surface and a convex image-side surface. Together with the first lens 11, it can better allow light to enter the lens and prevent excessive deflection of light on a certain lens surface, allowing light to propagate smoothly in the lens and reducing aberrations introduced by sharp deflections. At the same time, the design of the meniscus lens helps to optimize the light path, making the light path after entering the lens more compact, which helps to reduce the overall aperture and total optical length of the lens, meeting the requirements of miniaturization and lightweighting.

[0050] The first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, the sixth lens 16 and the seventh lens 17 adopt a negative-negative-positive-positive-positive-positive optical power combination, which can reasonably distribute the optical power of each lens to enable light to propagate smoothly in the lens, avoid excessive bending of light on any lens surface, and help ensure image quality.

[0051] At the same time, the surface shape of the lens affects the direction of light propagation and determines how the light bends when passing through the lens, which in turn affects the amount of light transmitted by the lens, the quality of the image and other characteristics.

[0052] In this embodiment, by rationally matching the surface shapes of the various lenses, while meeting the optical power requirements of each lens and achieving the required optical performance indicators (such as small size, large field of view, large target surface, large aperture, etc.), it is beneficial to further reduce the total optical length of the entire lens, thereby realizing a miniaturized lens design. In addition, it can also make the path of light smoother when passing through the entire lens, reduce unnecessary reflection and absorption, and help improve imaging quality.

[0053] The lens provided by the embodiment of the present invention uses only seven lenses. By reasonably matching the optical power and surface shape of each lens, the total optical length of the lens is reduced to 23.4 mm or less, the field of view (FOV) can reach 136°, the image plane diameter can reach 7.5 mm, the aperture number F reaches 1.8, and it can well correct aberrations to ensure sufficiently good image quality and stable high and low temperature resolution, thus realizing a lens that can take into account high resolution, compact structure, large field of view, large target surface, and large aperture.

[0054] As a feasible implementation method, Figure 1-Figure 3 As shown, the fifth lens 15 and the sixth lens 16 constitute a first cemented lens group G1.

[0055] Among them, such as Figure 1-Figure 3 As shown, gluing the fifth lens 15 and the sixth lens 16 together can minimize or eliminate chromatic aberration, thereby fully correcting the chromatic aberration of the lens. At the same time, it can also effectively reduce the air gap between the fifth lens 15 and the sixth lens 16, thereby reducing the overall optical length of the lens.

[0056] In addition, gluing the fifth lens 15 and the sixth lens 16 together can also reduce the air interface, thereby reducing reflection loss, and can reduce the number of assembly components between the fifth lens 15 and the sixth lens 16, simplifying the assembly process during the lens manufacturing process, reducing costs, and at the same time reducing the impact of lens tolerances such as tilt / eccentricity generated during the assembly process on the lens, thereby improving the stability of the lens.

[0057] It should be noted that the optical power of the first cemented lens group G1 can be positive or negative, and this embodiment of the present invention does not specifically limit this.

[0058] As a feasible implementation manner, the thickness of the fifth lens 15 is L5, the thickness of the sixth lens 16 is L6, and L5+L6≤3 mm.

[0059] Wherein, by controlling the thickness of the fifth lens 15 and the sixth lens 16 and being less than or equal to 3mm, the total length of the lens can be further compressed while ensuring the imaging quality, realizing a more compact design, so that the lens is easier to install in a narrow space, such as near the rearview mirror of a car or other restricted areas.

[0060] As a feasible implementation, the refractive index of the first lens 11 is n1, and the Abbe number is v1; the refractive index of the second lens 12 is n2, and the Abbe number is v2; the refractive index of the third lens 13 is n3, and the Abbe number is v3; the refractive index of the fourth lens 14 is n4, and the Abbe number is v4; the refractive index of the fifth lens 15 is n5, and the Abbe number is v5; the refractive index of the sixth lens 16 is n6, and the Abbe number is v6; the refractive index of the seventh lens 17 is n7, and the Abbe number is v7.

[0061] 1.75≤n1≤2.00; 25.89≤v1≤51.01;

[0062] 1.62≤n2≤2.10; 29.00≤v2≤71.00;

[0063] 1.80≤n3≤2.10; 25.29≤v3≤48.48;

[0064] 1.60≤n4≤1.90; 39.00≤v4≤61.00;

[0065] 1.43≤n5≤1.69; 47.51≤v5≤95.00;

[0066] 1.83≤n6≤2.10; 15.00≤v6≤25.94;

[0067] 1.61≤n7≤2.10; 22.63≤v7≤61.01.

[0068] Wherein, the refractive index is the ratio of the propagation speed of light in vacuum to the propagation speed of light in the medium, mainly used to describe the refractive ability of the material to light, and the refractive index of different materials is different.

[0069] The Abbe number is an index used to represent the dispersion ability of a transparent medium. The more serious the dispersion of the medium, the smaller the Abbe number; on the contrary, the lighter the dispersion of the medium, the larger the Abbe number.

[0070] In this embodiment, by reasonably limiting the refractive index and Abbe number of each lens, the aberration can be corrected to a greater extent, the imaging quality is improved, and the total length of the lens is further compressed.

[0071] As a feasible implementation, as Figure 1-Figure 3As shown, the utility model embodiment provides lens still includes flat filter CG, flat filter CG is located at the image side one side of seventh lens 17, it can play the protection effect to imaging sensor, prevent dust and pollution, and then guarantee the imaging effect of lens.

[0072] In certain cases, flat filter CG can also be used for correcting specific aberration or filtering unnecessary light, and the utility model embodiment does not make specific limitation to this.

[0073] Among them, imaging sensor is used to convert the light signal collected by lens into electrical signal, and then can generate digital image or video through a series of processing steps.

[0074] As a feasible implementation mode, the optical back focal length of lens is BFL, the optical total length of lens is TTL, and BFL / TTL is greater than or equal to 0.16.

[0075] Among them, the optical back focal length BFL of lens refers to the distance from the optical axis center of the image side of seventh lens 17 to the image plane, and the optical total length TTL of lens refers to the distance from the optical axis center of the object side of first lens 11 to the image plane.

[0076] In the embodiment, by reasonably limiting the ratio of the optical back focal length BFL and the optical total length TTL of lens, it can be ensured that the imaging sensor and flat filter and other structures have sufficient installation space, so that the lens can not interfere with the base and the shell during installation, and the lens assembly process is relatively simple.

[0077] As a feasible implementation mode, the maximum field of view angle of lens is FOV, the optical total length of lens is TTL, and FOV / TTL is greater than or equal to 5.

[0078] Among them, by reasonably limiting the ratio of the maximum field of view angle FOV and the optical total length TTL of lens, the field of view angle can be expanded while the volume is compressed, so that it can be applied to various application scenarios requiring large field of view angle and small design.

[0079] As a feasible implementation mode, the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, the sixth lens 16 and the seventh lens 14 are all glass spherical lenses.

[0080] Among them, compared with plastic lenses, the refractive index of glass lenses changes less with temperature, and setting each lens as a glass lens helps to maintain the stability of the focal length of each lens at different temperatures, so that the lens is not sensitive to high and low temperature, and the influence of high and low temperature on the whole lens can be well balanced, without obvious aberration or other optical problems due to temperature change, so as to ensure stable imaging quality under different environmental conditions.

[0081] Meanwhile, the first lens 11 , the second lens 12 , the third lens 13 , the fourth lens 14 , the fifth lens 15 , the sixth lens 16 and the seventh lens 14 are all spherical lenses, which is beneficial to reducing costs.

[0082] As a feasible implementation method, Figure 1-Figure 3 As shown, the lens also includes an aperture STO, which is located in the optical path between the third lens 13 and the fourth lens 14; or, the aperture STO is located in the optical path between the second lens 12 and the third lens 13; or, the aperture STO is located in the optical path between the fourth lens 14 and the fifth lens 15.

[0083] Among them, placing the aperture STO in the middle part of the lens is conducive to optimizing the path of light and ensuring that the light can be evenly distributed to the subsequent lens groups after passing through the aperture, thereby improving the imaging quality.

[0084] As a feasible implementation, the total optical length of the lens is TTL, and TTL≤23.4 mm.

[0085] The lens provided in this embodiment has a short overall length, a compact structure, and a small size, making it easy to install in various devices, especially in environments with limited space. At the same time, the compact design makes the lens more portable, convenient to carry and use.

[0086] As a feasible implementation method, the maximum field of view of the lens is FOV, and FOV is ≥136°.

[0087] The lens provided in this embodiment has a large field of view, can capture a wider scene, and can be suitable for applications that require panoramic coverage, such as vehicle-mounted rearview cameras, panoramic photography, monitoring systems, etc.

[0088] Specific embodiments of lenses applicable to the above-mentioned embodiments will be further described below with reference to the accompanying drawings.

[0089] Example 1

[0090] Continue to refer Figure 1 The lens provided in the first embodiment of the present invention includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a seventh lens L7 arranged in sequence along the optical axis from the object plane to the image plane.

[0091] The first lens 11 has negative optical power, the second lens 12 has negative optical power, the third lens 13 has positive optical power, the fourth lens 14 has positive optical power, the fifth lens 15 has positive optical power, the sixth lens 16 has negative optical power, and the seventh lens 17 has positive optical power.

[0092] The diaphragm STO is located in the light path between the third lens 13 and the fourth lens 14; and the flat filter CG is located on the image side of the seventh lens 17.

[0093] Table 1 details the surface shape, the radius of curvature, the thickness, the refractive index, the Abbe number and the half aperture of each lens in the lens provided by the embodiment one in a possible implementation manner, the lens in Table 1 corresponds to the lens shown in Table 1. Figure 1

[0094] Table 1: Design values of optical physical parameters of the lens

[0095]

[0096]

[0097] In Table 1, the surface number is numbered according to the surface order of each lens; “STO” represents the diaphragm of the lens; “IMA” represents the image surface of the lens; the radius of curvature represents the bending degree of the lens surface, the positive value represents that the surface is bent to the image side, and the negative value represents that the surface is bent to the object side, wherein “PL” represents that the surface is a plane, and the radius of curvature is infinite; the thickness represents the center axial distance from the current surface to the next surface, wherein, because the number of values of each parameter is different, there is an error in focusing, so the thickness of the 18th surface (S18) has a certain range, and the value can be adjusted as appropriate to achieve the purpose of clear focusing; the refractive index represents the deflection ability of the material between the current surface and the next surface to the light; the space represents that the current position is air, and the refractive index is 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to the light; the space represents that the current position is air; and the half aperture represents the corresponding light half height on the surface of each lens.

[0098] The lens of the embodiment one has a focal length f of 3.553 mm, a field of view angle of 136°, and an aperture of F1.8.

[0099] Figure 4 The lens provided by the embodiment one of the utility model has a spherical aberration curve diagram, wherein, the vertical direction in the diagram represents the normalization of the aperture, 0 represents on the optical axis, and the vertical direction top represents the maximum pupil radius; the horizontal direction represents the offset amount relative to the ideal focus point, and the unit is millimeter (mm). Different line curves in the diagram represent different wavelengths of lens imaging. Figure 4 The axial aberration of different wavelengths in the diagram is controlled within the range of (-0.02 mm, +0.05 mm), which indicates that the spherical aberration of the lens at each wavelength is well controlled.

[0100] Embodiment two

[0101] Continuing to refer to Figure 2 ​The lens provided by the second embodiment of the utility model comprises a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a seventh lens L7 which are sequentially arranged along an optical axis from an object plane to an image plane.

[0102] The first lens 11 has negative optical power, the second lens 12 has negative optical power, the third lens 13 has positive optical power, the fourth lens 14 has positive optical power, the fifth lens 15 has positive optical power, the sixth lens 16 has negative optical power, and the seventh lens 17 has positive optical power.

[0103] The diaphragm STO is located in the optical path between the third lens 13 and the fourth lens 14; and the flat filter CG is located on the image side of the seventh lens 17.

[0104] Table 2 details the surface shape, curvature radius, thickness, refractive index, Abbe number and half aperture of each lens in the lens provided by the second embodiment in a feasible implementation manner, and the lens in Table 2 corresponds to the lens shown in Table 1. Figure 2

[0105] Table 2: Design values of optical physical parameters of the lens

[0106]

[0107] In Table 2, the surface number is numbered according to the surface order of each lens; "STO" represents the diaphragm of the lens; "IMA" represents the image plane of the lens; the curvature radius represents the bending degree of the lens surface, the positive value represents that the surface is bent to the image plane side, and the negative value represents that the surface is bent to the object plane side, wherein "PL" represents that the surface is a plane, and the curvature radius is infinite; the thickness represents the center axis distance from the current surface to the next surface; wherein, because the number of parameter values is different, there is an error in focusing, so the thickness of the 18th surface (S18) has a certain range, and the value can be adjusted as needed to achieve the purpose of clear focusing; the refractive index represents the deflection ability of the material between the current surface and the next surface to the light; the space represents that the current position is air, and the refractive index is 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to the light; the space represents that the current position is air; and the half aperture represents the corresponding light half height on the surface of each lens.

[0108] The lens of the second embodiment has a focal length f of 3.529 mm, a field of view angle of 136°, and an aperture of F1.8.

[0109] Figure 5 ​This is a graph of the spherical aberration of the lens provided in Example 2 of the present invention. The vertical axis represents the normalized aperture, with 0 indicating the optical axis and the vertical vertex representing the maximum pupil radius. The horizontal axis represents the offset from the ideal focus, measured in millimeters (mm). The different linear curves in the graph represent different wavelengths imaged by the lens. Figure 5 The axial aberrations at different wavelengths are all controlled within the range of (-0.02mm, +0.05mm), indicating that the spherical aberration of the lens at each wavelength is well controlled.

[0110] Example 3

[0111] Continue to refer Figure 3 The lens provided in the third embodiment of the present invention includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a seventh lens L7 arranged in sequence along the optical axis from the object plane to the image plane.

[0112] The first lens 11 has negative optical power, the second lens 12 has negative optical power, the third lens 13 has positive optical power, the fourth lens 14 has positive optical power, the fifth lens 15 has positive optical power, the sixth lens 16 has negative optical power, and the seventh lens 17 has positive optical power.

[0113] The aperture STO is located in the optical path between the third lens 13 and the fourth lens 14 ; the flat filter CG is located on the image-side surface of the seventh lens 17 .

[0114] Table 3 details the surface shape, curvature radius, thickness, refractive index, Abbe number and half-aperture of each lens in the lens provided in Example 3 in a feasible implementation manner. The lens in Table 3 corresponds to Figure 3 The lens shown.

[0115] Table 3 Design values ​​of optical physical parameters of the lens

[0116]

[0117] In the table 3, the surface sequence number is numbered according to the surface sequence of each lens; "STO" represents the aperture of the lens; "IMA" represents the image surface of the lens; the radius of curvature represents the bending degree of the lens surface, the positive value represents that the surface is bent to the image surface side, and the negative value represents that the surface is bent to the object surface side, wherein "PL" represents that the surface is a plane, and the radius of curvature is infinite; the thickness represents the center axis distance from the current surface to the next surface, wherein, because the parameter value is different, the focusing has an error, so the thickness of the 18th surface (S18) has a certain range, and the value can be adjusted to achieve the purpose of clear focusing; the refractive index represents the deflection ability of the material between the current surface and the next surface to the light, and the space represents that the current position is air, and the refractive index is 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to the light, and the space represents that the current position is air; the half radius represents the corresponding light half height on the surface of each lens.

[0118] The lens of the third embodiment has a focal length f of 3.593 mm, a field of view angle of 136°, and an aperture of F1.8.

[0119] Figure 6 The lens provided by the third embodiment of the utility model has a spherical aberration curve diagram, wherein, the normalized aperture is represented in the vertical direction of the diagram, 0 represents on the optical axis, and the vertical direction top represents the maximum pupil radius; the horizontal direction represents the offset of the relative ideal focus point, and the unit is millimeter (mm). Different line curves in the diagram represent different wavelengths of lens imaging. Figure 6 The axial aberration of different wavelengths is controlled within the range of (-0.02 mm, +0.06 mm), which indicates that the spherical aberration of the lens at each wavelength is well controlled.

[0120] In order to more clearly illustrate the above embodiments, table 4 details the specific optical physical parameters of each lens in the lens provided by the first to third embodiments of the utility model.

[0121] Table 4: Design values of optical physical parameters of the lens

[0122] Example 1 Example 2 Example 3 n1 1.804 1.885 1.950 n2 2.055 1.674 1.900 n3 2.042 2.052 1.850 n4 1.813 1.847 1.650 n5 1.642 1.614 1.480 n6 2.045 2.074 1.883 n7 2.051 1.656 1.850 v1 50.00 26.89 50.01 v2 30.00 70.00 50.00 v3 41.37 26.29 47.48 v4 50.00 40.00 60.00 v5 95.00 48.51 95.00 v6 20.00 15.00 24.94 v7 23.63 40.00 60.01 BFL / TTL 0.163 0.188 0.192 L5+L6 2.397 2.517 2.576 FOV / TTL 5.84 5.86 5.84

[0123] The above specific embodiments do not constitute a limitation on the protection scope of the utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principles of the utility model should be included in the protection scope of the utility model.

Claims

1. A lens, characterized in that: comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged in sequence along the optical axis from the object plane to the image plane; The first lens has negative optical power, its object side surface is convex, and its image side surface is concave; The second lens has negative optical power, its object side surface is concave, and its image side surface is convex; The third lens has positive refractive power, its object side surface is convex, and its image side surface is flat or concave; The fourth lens has positive refractive power, its object side surface is concave, and its image side surface is convex; The fifth lens has positive refractive power, and its object-side surface is convex, and its image-side surface is convex; The sixth lens has negative optical power, its object side surface is concave, and its image side surface is convex; The seventh lens has positive refractive power, its object-side surface is convex, and its image-side surface is concave or convex; The fifth lens and the sixth lens form a first cemented lens group; The thickness of the fifth lens is L5, the thickness of the sixth lens is L6, and L5+L6≤3 mm.

2. The lens according to claim 1, wherein: The refractive index of the first lens is n1, and the Abbe number is v1; the refractive index of the second lens is n2, and the Abbe number is v2; the refractive index of the third lens is n3, and the Abbe number is v3; the refractive index of the fourth lens is n4, and the Abbe number is v4; the refractive index of the fifth lens is n5, and the Abbe number is v5; the refractive index of the sixth lens is n6, and the Abbe number is v6; the refractive index of the seventh lens is n7, and the Abbe number is v7; 1.75≤n1≤2.00;25.89≤v1≤51.01; 1.62≤n2≤2.10;29.00≤v2≤71.00; 1.80≤n3≤2.10;25.29≤v3≤48.48; 1.60≤n4≤1.90;39.00≤v4≤61.00; 1.43≤n5≤1.69;47.51≤v5≤95.00; 1.83≤n6≤2.10;15.00≤v6≤25.94; 1.61≤n7≤2.10;22.63≤v7≤61.

01.

3. The lens according to claim 1, wherein: The optical back focus of the lens is BFL, the total optical length of the lens is TTL, and BFL / TTL≥0.

16.

4. The lens according to claim 1, wherein: The maximum field of view of the lens is FOV, the total optical length of the lens is TTL, and FOV / TTL≥5.

5. The lens according to claim 1, wherein: The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are all glass spherical lenses.

6. The lens according to claim 1, wherein: The lens further includes an aperture; The aperture is located in the optical path between the third lens and the fourth lens; Alternatively, the aperture is located in the optical path between the second lens and the third lens; Alternatively, the aperture is located in the optical path between the fourth lens and the fifth lens.

7. The lens according to claim 1, wherein: The total optical length of the lens is TTL, TTL≤23.4mm.

8. The lens according to claim 1, wherein: The maximum field of view of the lens is FOV, and FOV is ≥ 136°.

Images