Large-target-surface wide-angle TOF lens
By combining spherical lenses, the high cost of large-area wide-angle TOF lenses was solved, achieving high-quality imaging results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-06
- Publication Date
- 2026-03-13
AI Technical Summary
Existing large-area wide-angle TOF lenses are expensive due to the use of aspherical lenses, making it difficult to effectively control development costs during the prototype stage.
The system employs a first lens group, a symmetrical lens group, and a second lens group, all composed of spherical lenses. The first lens group reduces the angle of incident light, while the symmetrical and second lens groups correct aberrations, thus achieving high-quality imaging with a large target surface and a wide viewing angle.
It reduces lens costs, improves image quality, meets the imaging requirements of large target surfaces and wide viewing angles, and optimizes lens performance.
Smart Images
Figure CN223993001U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of optical lens technology, specifically to a large-area wide-angle TOF lens. Background Technology
[0002] Time-of-Flight (TOF) is a 3D vision sensing method rooted in depth sensor technology. It uses pixel arrays to acquire high-resolution depth distribution across a scene, offering advantages such as fast response time, high measurement accuracy, and strong anti-interference capabilities. TOF technology is applied in mobile phones, automobiles, industry, facial recognition, logistics, gaming, 3D printing, and robotics, with TOF lenses being an indispensable component. TOF lenses typically operate in the near-infrared band and consist of multiple lenses combined to create a lens with a large field of view, high illumination, and high resolution.
[0003] Currently, for TOF lenses with large target surfaces, aspherical lenses are mostly used to achieve a small total track length (TTL), improve image quality, and reduce aberrations. However, both molded glass aspherical lenses and injection-molded plastic aspherical lenses have high initial costs, which is not conducive to cost control during the prototype development stage of TOF devices. Utility Model Content
[0004] In view of this, the present invention provides a large-area wide-angle TOF lens, which can overcome the technical problem that the existing large-area wide-angle TOF lens requires the use of aspherical lenses, resulting in high cost.
[0005] This invention provides a large-area wide-angle TOF lens, comprising a first lens group, a symmetrical lens group, and a second lens group arranged sequentially from the object plane to the image plane. The first lens group includes several meniscus lenses with negative optical power and convex object-side surfaces to reduce the angle of incident light. The symmetrical lens group includes two symmetrically arranged meniscus lenses with positive optical power. In the symmetrical lens group, the object-side surface of the meniscus lens closer to the object plane is concave, and the image-side surface is convex. In the symmetrical lens group, the object-side surface of the meniscus lens closer to the image plane is convex, and the image-side surface is concave. The second lens group includes several meniscus lenses with positive optical power and a biconvex lens with positive optical power to correct aberrations in the beam emitted from the symmetrical lens group. All lenses in the first lens group, the symmetrical lens group, and the second lens group are spherical lenses.
[0006] This invention discloses a large-area wide-angle TOF lens. The first lens group reduces the angle of large-angle incident light. The object-side surface of the meniscus lens in the first lens group is convex, which reduces the incident angle of large-angle light entering the lens, thereby effectively reducing the introduction of higher-order aberrations and better controlling tolerances. The symmetrical lens group uses two symmetrically arranged meniscus lenses with positive optical power. The object-side surface of the meniscus lens closer to the object plane is concave, and the image-side surface is convex. The object-side surface of the meniscus lens closer to the image plane in the symmetrical lens group is convex, and the image-side surface is concave. This symmetrical lens group adopts a principle similar to a double Gaussian structure lens, which can effectively correct aberrations such as spherical aberration and coma. Finally, the second lens group uses a meniscus lens with positive optical power and a double convex lens with positive optical power near the image plane to further correct aberrations and achieve the required image quality. Through the above arrangement, high-quality imaging with a large target area and wide angle of view can be achieved by using spherical lenses throughout the lens, eliminating the need for aspherical lenses and greatly reducing lens costs.
[0007] In one optional embodiment, the first lens group includes a first lens and a second lens, the focal lengths of the first lens and the second lens satisfying the following condition:
[0008] -12<f1 / f<-5, -5<f2 / f<0
[0009] Where f1 is the focal length of the first lens, f2 is the focal length of the second lens, and f is the effective focal length of the large-area wide-angle TOF lens.
[0010] By specifying that the focal length range of the first lens and the second lens in the first lens group is within the aforementioned range, the focusing and angle of light can be precisely controlled, thereby optimizing the lens performance, helping to reduce the total optical length, and improving image quality.
[0011] In one alternative embodiment, the symmetrical lens group includes a third lens and a fourth lens, the focal lengths of which satisfy the following condition:
[0012] 8<f3 / f<15, 500<f4 / f<650
[0013] Where f3 is the focal length of the third lens and f4 is the focal length of the fourth lens.
[0014] By specifying the focal length range of the third and fourth lenses in a symmetrical lens group, it is helpful to further correct light, reduce aberrations, and improve image sharpness.
[0015] In one optional embodiment, the second lens group includes a fifth lens, a sixth lens, and a seventh lens. The fifth and seventh lenses are both meniscus lenses with positive optical power, and the sixth lens is a biconvex lens with positive optical power. The focal lengths of the fifth, sixth, and seventh lenses satisfy the following condition:
[0016] 3<f5 / f<8, 2<f6 / f<7, 4<f7 / f<9
[0017] Where f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, and f7 is the focal length of the seventh lens.
[0018] The specified focal length ranges of the fifth, sixth, and seventh lenses in the second lens group help to further correct aberrations and improve image quality. This design optimizes the lens's optical performance, making it adaptable to different imaging needs.
[0019] In one optional implementation, the refractive indices of the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, and seventh lens satisfy the following condition:
[0020] 1.7<n1<1.95; 1.4<n2<1.6; 1.8<n3<2.0; 1.8<n4<2.0; 1.8<n5<2.0; 1.7<n6<1.95; 1.7<n7<1.95;
[0021] Wherein, n1 is the refractive index of the first lens, n2 is the refractive index of the second lens, n3 is the refractive index of the third lens, n4 is the refractive index of the fourth lens, n5 is the refractive index of the fifth lens, n6 is the refractive index of the sixth lens, and n7 is the refractive index of the seventh lens L7.
[0022] By specifying the refractive index range of each lens, it can be ensured that the selection of lens materials can meet specific optical performance requirements, thereby improving the overall performance and image quality of the lens.
[0023] In one alternative implementation, an aperture stop is provided between the third lens and the fourth lens.
[0024] Setting an aperture stop between the third and fourth lenses allows control over the amount of light entering the lens, which helps adjust the depth of field and aperture size, and optimizes image exposure and contrast.
[0025] In one optional embodiment, the focal length ranges of the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, and seventh lens are -35.2500mm to -35.2600mm, -14.7500mm to 14.7600mm, 44.6200mm to 44.6300mm, 3046.3700mm to 3046.3800mm, 26.3300mm to 26.3400mm, 25.1900mm to 25.2000mm, and 35.4700mm to 35.4800mm, respectively.
[0026] By specifying the focal length range of each lens, the optical performance of the lens can be precisely controlled, thereby improving the lens's image quality and adaptability.
[0027] In one alternative embodiment, the radius of curvature of the object-side surface of the first lens is 26.10 mm to 26.20 mm, and the radius of curvature of the image-side surface of the first lens is 11.90 mm to 12.00 mm.
[0028] The radius of curvature of the object side of the second lens is 58.30 mm to 58.40 mm, and the radius of curvature of the image side of the second lens is 7.70 mm to 7.80 mm.
[0029] The radius of curvature of the object side of the third lens is -30.00 mm to -30.10 mm, and the radius of curvature of the image side of the third lens is -20.20 mm to -20.30 mm.
[0030] The radius of curvature of the object side of the fourth lens is 19.50 mm to 19.60 mm, and the radius of curvature of the image side of the fourth lens is 16.40 mm to 16.50 mm.
[0031] The radius of curvature of the object side of the fifth lens is 234.40 mm to 234.50 mm, and the radius of curvature of the image side of the fifth lens is -19.20 mm to -19.30 mm.
[0032] The radius of curvature of the object side of the sixth lens is 21.60 mm to 21.70 mm, and the radius of curvature of the image side of the sixth lens is -37.80 mm to -37.90 mm.
[0033] The radius of curvature of the object side of the seventh lens is 13.40 mm to 13.50 mm, and the radius of curvature of the image side of the seventh lens is 32.40 mm to 32.50 mm.
[0034] By specifying the radius of curvature of the object-side and image-side surfaces of each lens, the refraction and focusing of light can be precisely controlled, thereby optimizing the imaging performance of the lens, reducing optical distortion, and improving the clarity and realism of the image.
[0035] In one alternative embodiment, the distance from the object side surface of the first lens to the image side surface of the first lens is 5.60 mm to 5.70 mm.
[0036] The distance from the image side of the first lens to the object side of the second lens is 11.45 mm to 11.55 mm.
[0037] The distance from the object side surface of the second lens to the image side surface of the second lens is 9.10 mm to 9.20 mm;
[0038] The distance from the image side of the second lens to the object side of the third lens is 4.10 mm to 4.20 mm;
[0039] The distance from the object side of the third lens to the image side of the third lens is 7.96 mm to 8.06 mm;
[0040] The distance from the image side of the third lens to the aperture stop is 0.94 mm to 1.04 mm;
[0041] The distance from the aperture stop to the object side of the fourth lens is 1.16 mm to 1.26 mm;
[0042] The distance from the object side of the fourth lens to the image side of the fourth lens is 6.84 mm to 6.94 mm;
[0043] The distance from the image side of the fourth lens to the object side of the fifth lens is 2.24 mm to 2.34 mm;
[0044] The distance from the object side of the fifth lens to the image side of the fifth lens is 2.75 mm to 2.85 mm;
[0045] The distance from the image side of the fifth lens to the object side of the sixth lens is 2.70 mm to 2.80 mm;
[0046] The distance from the object side of the sixth lens to the image side of the sixth lens is 4.30 mm to 4.40 mm;
[0047] The distance from the image side of the sixth lens to the object side of the seventh lens is 2.80 mm to 2.90 mm;
[0048] The distance from the object side of the seventh lens to the image side of the seventh lens is 8.25 mm to 8.35 mm;
[0049] The distance from the image side to the image plane of the seventh lens is 3.84 mm to 3.94 mm.
[0050] By specifying the distance between each lens, the propagation path of light inside the lens can be precisely controlled, optimizing the focusing and imaging of light, which helps to improve the optical performance and image quality of the lens.
[0051] In one alternative embodiment, the lenses in the first lens group, the symmetrical lens group, and the second lens group are all coated with a broadband antireflective coating with a transmittance of 99.3% to 99.7% for light with wavelengths between 400 nm and 1100 nm.
[0052] By applying a broadband antireflective coating, the transmittance of light within a specific wavelength range can be increased, while reflection and scattering are reduced, thereby improving the light efficiency and image quality of the lens. Attached Figure Description
[0053] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0054] Figure 1 This is a schematic diagram of the structure of the large-area wide-angle TOF lens according to an embodiment of the present invention;
[0055] Figure 2 A dot diagram of the large-area wide-angle TOF lens according to an embodiment of this utility model;
[0056] Figure 3 This is a relative illumination diagram of the large-area wide-angle TOF lens according to an embodiment of the present invention;
[0057] Figure 4 This is an axial aberration diagram of the large-area wide-angle TOF lens in an embodiment of this utility model;
[0058] Figure 5 The MTF curve of the large-area wide-angle TOF lens in this embodiment of the present invention;
[0059] Figure 6 This is a 50LP / MM defocus MTF diagram of the large-area wide-angle TOF lens of this utility model embodiment.
[0060] Explanation of reference numerals in the attached figures:
[0061] L1 - First lens; L2 - Second lens; L3 - Third lens; STO - Aperture stop; L4 - Fourth lens; L5 - Fifth lens; L6 - Sixth lens; L7 - Seventh lens. Detailed Implementation
[0062] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.
[0063] In the description of this utility model, it should be noted that the term "several" refers to one or more. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0064] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.
[0065] In related technologies, some small TOF lenses use a 4G2P architecture and a 1 / 4-inch sensor, with a maximum image height of φ4.5mm. Some wide-angle TOF lenses with a wide working distance and large aperture use a 6G architecture and a 1 / 3.6-inch sensor, with a maximum image height of φ5.3mm. The maximum image height of these TOF lenses cannot meet the requirements for imaging large target surfaces.
[0066] The design of a large-aperture wide-angle TOF lens means significant edge aberrations, making edge aberration optimization a key focus. Currently, to improve the image quality of large-aperture wide-angle TOF lenses, related technologies employ multiple aspherical lenses, leading to increased costs.
[0067] In view of this, this utility model proposes a large-area wide-angle TOF lens to optimize the problems of small target area, small field of view, and high trial production cost of existing TOF lenses. In this utility model embodiment, multiple spherical lenses are used to correct off-axis aberrations, improve lens MTF, and increase the field of view, so as to achieve low-cost trial production of a lens that matches TOF devices.
[0068] Please see Figure 1The large-area wide-angle TOF lens of this utility model embodiment includes a first lens group, a symmetrical lens group, and a second lens group arranged sequentially from the object plane to the image plane. The first lens group includes several meniscus lenses with negative optical power and convex object-side surfaces to reduce the angle of incident light. The symmetrical lens group includes two symmetrically arranged meniscus lenses with positive optical power. In the symmetrical lens group, the object-side surface of the meniscus lens closer to the object plane is concave, and the image-side surface is convex. In the symmetrical lens group, the object-side surface of the meniscus lens closer to the image plane is convex, and the image-side surface is concave. The second lens group includes several meniscus lenses with positive optical power and a biconvex lens with positive optical power to correct aberrations of the beam emitted from the symmetrical lens group. The lenses in the first lens group, the symmetrical lens group, and the second lens group are all spherical lenses.
[0069] Specifically, the lenses in the first lens group, the symmetrical lens group, and the second lens group are all spherical lenses. The spherical lenses are made of various types of glass. That is, the lenses in this embodiment of the present invention are all spherical glass lenses, and different types of glass have different refractive indices.
[0070] The working distance of the large-area wide-angle TOF lens in this embodiment of the invention is 5m to infinity.
[0071] In the first lens group, the meniscus lens used has negative optical power, and the light rays passing through the first lens group are divergent.
[0072] In the symmetrical lens group, the meniscus lens used has positive optical power, and the light rays passing through the symmetrical lens group are convergent. At the same time, the two symmetrically arranged meniscus lenses in the symmetrical lens group are based on the principle of double Gaussian structure lens, which can effectively correct aberrations such as spherical aberration and coma.
[0073] The second lens group uses a combination of a meniscus lens and a biconvex lens. Both the meniscus lens and the biconvex lens have positive optical power, which further converges the light beam to reduce the overall length of the lens.
[0074] This embodiment of the invention achieves an imaging target surface size of 9.5mm, a lens FOV of 115°, and an application wavelength of 940nm through the combination of a first lens group, a symmetrical lens group, and a second lens group. This ensures imaging quality and uses low-cost glass spherical lenses throughout, better meeting the needs of large-size imaging targets for lenses.
[0075] This invention discloses a large-area wide-angle TOF lens. The first lens group reduces the angle of large-angle incident light. The object-side surface of the meniscus lens in the first lens group is convex, which reduces the angle of incidence relative to the lens when large-angle light enters it, effectively reducing the introduction of higher-order aberrations and better controlling tolerances. The symmetrical lens group uses two symmetrically arranged meniscus lenses with positive optical power. The object-side surface of the meniscus lens closer to the object plane is concave, and the image-side surface is convex. The object-side surface of the meniscus lens closer to the image plane in the symmetrical lens group is convex, and the image-side surface is concave. This symmetrical lens group, employing a principle similar to a double Gaussian structure lens, can effectively correct aberrations such as spherical aberration and coma. Finally, the second lens group uses a meniscus lens with positive optical power and a double convex lens with positive optical power near the image plane to further correct aberrations and achieve the required image quality. Through this arrangement, high-quality imaging with a large target area and wide viewing angle can be achieved by using spherical lenses throughout the lens, eliminating the need for aspherical lenses and significantly reducing lens costs.
[0076] In one optional embodiment, the first lens group includes a first lens L1 and a second lens L2, the focal lengths of the first lens L1 and the second lens L2 satisfying the following conditions: -12 < f1 / f < -5, -5 < f2 / f < 0, where f1 is the focal length of the first lens L1, f2 is the focal length of the second lens L2, and f is the effective focal length of the large target area wide-angle TOF lens.
[0077] The symmetrical lens group includes a third lens L3 and a fourth lens L4. The focal lengths of the third lens L3 and the fourth lens L4 satisfy the following conditions: 8 < f3 / f < 15, 500 < f4 / f < 650, where f3 is the focal length of the third lens L3 and f4 is the focal length of the fourth lens L4.
[0078] The second lens group includes a fifth lens L5, a sixth lens L6, and a seventh lens L7. Both the fifth lens L5 and the seventh lens L7 are meniscus lenses with positive optical power, and the sixth lens L6 is a biconvex lens with positive optical power. The focal lengths of the fifth lens L5, the sixth lens L6, and the seventh lens L7 satisfy the following conditions: 3 < f5 / f < 8, 2 < f6 / f < 7, 4 < f7 / f < 9, where f5 is the focal length of the fifth lens L5, f6 is the focal length of the sixth lens L6, and f7 is the focal length of the seventh lens L7.
[0079] For example, f1 / f = -6, f2 / f = -1, f3 / f = 14, f4 / f = 600, f5 / f = 7, f6 / f = 6, f7 / f = 8, or f1 / f = -11, f2 / f = -4, f3 / f = 9, f4 / f = 510, f5 / f = 4, f6 / f = 3, f7 / f = 3.
[0080] By ensuring that the focal lengths of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 fall within the aforementioned range, the focusing and angle of light can be precisely controlled, further correcting the light, reducing aberrations, and improving image quality.
[0081] In one optional embodiment, the refractive indices of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 satisfy the following condition:
[0082] 1.7<n1<1.95; 1.4<n2<1.6; 1.8<n3<2.0; 1.8<n4<2.0; 1.8<n5<2.0; 1.7<n6<1.95; 1.7<n7<1.95;
[0083] Wherein, n1 is the refractive index of the first lens L1, n2 is the refractive index of the second lens L2, n3 is the refractive index of the third lens L3, n4 is the refractive index of the fourth lens L4, n5 is the refractive index of the fifth lens L5, n6 is the refractive index of the sixth lens L6, and n7 is the refractive index of the seventh lens L7.
[0084] For example, n1 = 1.94; n2 = 1.5; n3 = 1.9; n4 = 1.9; n5 = 1.95; n6 = 1.90; n7 = 1.98, or n1 = 1.71; n2 = 1.45; n3 = 1.85; n4 = 1.89; n5 = 1.85; n6 = 1.80; n7 = 1.75.
[0085] By specifying the refractive index range of each lens, it can be ensured that the selection of lens materials can meet specific optical performance requirements, thereby improving the overall performance and image quality of the lens.
[0086] In one alternative embodiment, an aperture stop STO is provided between the third lens L3 and the fourth lens L4.
[0087] The aperture stop (STO) of a lens is used to control the amount of light entering the entire lens.
[0088] Setting an aperture stop STO between the third lens L3 and the fourth lens L4 can control the amount of light entering the lens, which helps to adjust the depth of field and aperture size, and optimize image exposure and contrast.
[0089] In one optional embodiment, the focal length ranges of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are -35.2500mm to -35.2600mm, -14.7500mm to 14.7600mm, 44.6200mm to 44.6300mm, 3046.3700mm to 3046.3800mm, 26.3300mm to 26.3400mm, 25.1900mm to 25.2000mm, and 35.4700mm to 35.4800mm, respectively.
[0090] In one example, the focal lengths of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are -35.2500mm, -14.7500mm, 44.6200mm, 3046.3700mm, 26.3300mm, 25.1900mm, and 35.4700mm, respectively; or, the focal lengths of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are -35.2600mm, 14.7600mm, 44.6300mm, 3046.3800mm, 26.3400mm, 25.2000mm, and 35.4800mm, respectively.
[0091] By specifying the focal length range of each lens, the optical performance of the lens can be precisely controlled, thereby improving the lens's image quality and adaptability.
[0092] In one optional embodiment, the radius of curvature of the object side of the first lens L1 is 26.10 mm to 26.20 mm, and the radius of curvature of the image side of the first lens L1 is 11.90 mm to 12.00 mm.
[0093] The radius of curvature of the object side of the second lens L2 is 58.30 mm to 58.40 mm, and the radius of curvature of the image side of the second lens L2 is 7.70 mm to 7.80 mm.
[0094] The radius of curvature of the object side of the third lens L3 is -30.00 mm to -30.10 mm, and the radius of curvature of the image side of the third lens L3 is -20.20 mm to -20.30 mm.
[0095] The radius of curvature of the object side of the fourth lens L4 is 19.50 mm to 19.60 mm, and the radius of curvature of the image side of the fourth lens L4 is 16.40 mm to 16.50 mm.
[0096] The radius of curvature of the object side of the fifth lens L5 is 234.40 mm to 234.50 mm, and the radius of curvature of the image side of the fifth lens L5 is -19.20 mm to -19.30 mm.
[0097] The radius of curvature of the object side of the sixth lens L6 is 21.60 mm to 21.70 mm, and the radius of curvature of the image side of the sixth lens L6 is -37.80 mm to -37.90 mm.
[0098] The radius of curvature of the object side of the seventh lens L7 is 13.40 mm to 13.50 mm, and the radius of curvature of the image side of the seventh lens L7 is 32.40 mm to 32.50 mm.
[0099] In one example, the radius of curvature of the object side of the first lens L1 is 26.10 mm, and the radius of curvature of the image side of the first lens L1 is 11.90 mm.
[0100] The radius of curvature of the object side of the second lens L2 is 58.30 mm, and the radius of curvature of the image side of the second lens L2 is 7.70 mm.
[0101] The radius of curvature of the object side of the third lens L3 is -30.00 mm, and the radius of curvature of the image side of the third lens L3 is -20.20 mm.
[0102] The radius of curvature of the object side of the fourth lens L4 is 19.50 mm, and the radius of curvature of the image side of the fourth lens L4 is 16.40 mm.
[0103] The radius of curvature of the object side of the fifth lens L5 is 234.40 mm, and the radius of curvature of the image side of the fifth lens L5 is -19.20 mm.
[0104] The radius of curvature of the object side of the sixth lens L6 is 21.60 mm, and the radius of curvature of the image side of the sixth lens L6 is -37.80 mm.
[0105] The radius of curvature of the object side of the seventh lens L7 is 13.40 mm, and the radius of curvature of the image side of the seventh lens L7 is 32.40 mm.
[0106] In another example, the radius of curvature of the object side of the first lens L1 is 26.20 mm, and the radius of curvature of the image side of the first lens L1 is 12.00 mm.
[0107] The radius of curvature of the object side of the second lens L2 is 58.40 mm, and the radius of curvature of the image side of the second lens L2 is 7.80 mm.
[0108] The radius of curvature of the object side of the third lens L3 is -30.10 mm, and the radius of curvature of the image side of the third lens L3 is -20.30 mm.
[0109] The radius of curvature of the object side of the fourth lens L4 is 19.60 mm, and the radius of curvature of the image side of the fourth lens L4 is 16.50 mm.
[0110] The radius of curvature of the object side of the fifth lens L5 is 234.50 mm, and the radius of curvature of the image side of the fifth lens L5 is -19.30 mm.
[0111] The radius of curvature of the object side of the sixth lens L6 is 21.70 mm, and the radius of curvature of the image side of the sixth lens L6 is -37.90 mm.
[0112] The radius of curvature of the object side of the seventh lens L7 is 13.50 mm, and the radius of curvature of the image side of the seventh lens L7 is 32.50 mm.
[0113] By specifying the radius of curvature of the object-side and image-side surfaces of each lens, the refraction and focusing of light can be precisely controlled, thereby optimizing the imaging performance of the lens, reducing optical distortion, and improving the clarity and realism of the image.
[0114] In one alternative embodiment, the distance from the object side surface of the first lens L1 to the image side surface of the first lens L1 is 5.60 mm to 5.70 mm.
[0115] The distance from the image side of the first lens L1 to the object side of the second lens L2 is 11.45 mm to 11.55 mm.
[0116] The distance from the object side surface of the second lens L2 to the image side surface of the second lens L2 is 9.10 mm to 9.20 mm;
[0117] The distance from the image side of the second lens L2 to the object side of the third lens L3 is 4.10 mm to 4.20 mm.
[0118] The distance from the object side surface of the third lens L3 to the image side surface of the third lens L3 is 7.96 mm to 8.06 mm.
[0119] The distance from the image side of the third lens L3 to the aperture STO is 0.94 mm to 1.04 mm;
[0120] The distance from the aperture stop STO to the object side of the fourth lens L4 is 1.16 mm to 1.26 mm;
[0121] The distance from the object side surface of the fourth lens L4 to the image side surface of the fourth lens L4 is 6.84 mm to 6.94 mm;
[0122] The distance from the image side of the fourth lens L4 to the object side of the fifth lens L5 is 2.24 mm to 2.34 mm;
[0123] The distance from the object side surface of the fifth lens L5 to the image side surface of the fifth lens L5 is 2.75mm to 2.85mm;
[0124] The distance from the image side of the fifth lens L5 to the object side of the sixth lens L6 is 2.70 mm to 2.80 mm;
[0125] The distance from the object side surface of the sixth lens L6 to the image side surface of the sixth lens L6 is 4.30 mm to 4.40 mm;
[0126] The distance from the image side of the sixth lens L6 to the object side of the seventh lens L7 is 2.80 mm to 2.90 mm;
[0127] The distance from the object side surface of the seventh lens L7 to the image side surface of the seventh lens L7 is 8.25mm to 8.35mm;
[0128] The distance from the image side to the image plane of the seventh lens L7 is 3.84 mm to 3.94 mm.
[0129] In one example, the distance from the object side surface of the first lens L1 to the image side surface of the first lens L1 is 5.60 mm;
[0130] The distance from the image side of the first lens L1 to the object side of the second lens L2 is 11.45 mm;
[0131] The distance from the object side surface of the second lens L2 to the image side surface of the second lens L2 is 9.10 mm;
[0132] The distance from the image side of the second lens L2 to the object side of the third lens L3 is 4.10 mm;
[0133] The distance from the object side surface of the third lens L3 to the image side surface of the third lens L3 is 7.96 mm;
[0134] The distance from the image side of the third lens L3 to the aperture STO is 0.94 mm;
[0135] The distance from the aperture stop STO to the object side of the fourth lens L4 is 1.16 mm;
[0136] The distance from the object side surface of the fourth lens L4 to the image side surface of the fourth lens L4 is 6.84 mm;
[0137] The distance from the image side of the fourth lens L4 to the object side of the fifth lens L5 is 2.24 mm;
[0138] The distance from the object side surface of the fifth lens L5 to the image side surface of the fifth lens L5 is 2.75mm;
[0139] The distance from the image-side surface of the fifth lens L5 to the object-side surface of the sixth lens L6 is 2.70 mm;
[0140] The distance from the object side surface of the sixth lens L6 to the image side surface of the sixth lens L6 is 4.30 mm;
[0141] The distance from the image-side surface of the sixth lens L6 to the object-side surface of the seventh lens L7 is 2.80 mm;
[0142] The distance from the object side surface of the seventh lens L7 to the image side surface of the seventh lens L7 is 8.25mm;
[0143] The distance from the image side to the image plane of the seventh lens L7 is 3.84 mm.
[0144] In another example, the distance from the object side surface of the first lens L1 to the image side surface of the first lens L1 is 5.70 mm;
[0145] The distance from the image side of the first lens L1 to the object side of the second lens L2 is 11.55 mm.
[0146] The distance from the object side surface of the second lens L2 to the image side surface of the second lens L2 is 9.20 mm;
[0147] The distance from the image side of the second lens L2 to the object side of the third lens L3 is 4.20 mm;
[0148] The distance from the object side surface of the third lens L3 to the image side surface of the third lens L3 is 8.06 mm;
[0149] The distance from the image side of the third lens L3 to the aperture STO is 1.04 mm;
[0150] The distance from the aperture stop STO to the object side surface of the fourth lens L4 is 1.26 mm;
[0151] The distance from the object side surface of the fourth lens L4 to the image side surface of the fourth lens L4 is 6.94 mm;
[0152] The distance from the image-side surface of the fourth lens L4 to the object-side surface of the fifth lens L5 is 2.34 mm;
[0153] The distance from the object side surface of the fifth lens L5 to the image side surface of the fifth lens L5 is 2.85mm;
[0154] The distance from the image-side surface of the fifth lens L5 to the object-side surface of the sixth lens L6 is 2.80 mm;
[0155] The distance from the object side surface of the sixth lens L6 to the image side surface of the sixth lens L6 is 4.40 mm;
[0156] The distance from the image-side surface of the sixth lens L6 to the object-side surface of the seventh lens L7 is 2.90 mm;
[0157] The distance from the object side surface of the seventh lens L7 to the image side surface of the seventh lens L7 is 8.35mm;
[0158] The distance from the image side surface to the image plane of the seventh lens L7 is 3.94 mm.
[0159] By specifying the distance between each lens, the propagation path of light inside the lens can be precisely controlled, optimizing the focusing and imaging of light, which helps to improve the optical performance and image quality of the lens.
[0160] In one alternative embodiment, the lenses in the first lens group, the symmetrical lens group, and the second lens group are all coated with a broadband antireflective coating with a transmittance of 99.3% to 99.7% for light with wavelengths between 400 nm and 1100 nm.
[0161] By applying a broadband antireflective coating, the transmittance of light within a specific wavelength range can be increased, while reflection and scattering are reduced, thereby improving the light efficiency and image quality of the lens.
[0162] The following section will verify the beneficial effects of the large-area wide-angle TOF lens of this invention with reference to a preferred embodiment.
[0163] The large-area wide-angle TOF lens consists of a first lens L1, a second lens L2, a third lens L3, an aperture stop STO, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and a target surface, fixedly arranged from the object plane to the image plane. The first lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5, sixth lens L6, and seventh lens L7 are all spherical lenses made of glass. Table 1 shows the focal length and materials used for each lens in the large-area wide-angle TOF lens.
[0164] Table 1. Focal length and material parameters of the lenses
[0165] Optical component name Focal length / mm Material First lens L1 -35.2522 D-LAF50-25 Second lens L2 -14.7519 H-LAK11 Third lens L3 44.6282 H-ZLAF92 Fourth lens L4 3046.3723 H-ZF73 Fifth lens L5 26.3314 H-LAK59A Sixth lens L6 25.1972 H-ZPK7 Seventh lens L7 35.4709 H-ZPK7
[0166] The curvature radius, thickness, and surface type of each lens in a large-area wide-angle TOF lens are shown in Table 2.
[0167] Table 2. Parameters of lens radius of curvature, thickness, and surface type.
[0168]
[0169]
[0170] In Table 2, numbers 1, 3, 5, 8, 10, 12, and 14 represent the object-side surfaces of the first lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5, sixth lens L6, and seventh lens L7, respectively. Numbers 2, 4, 6, 9, 11, 13, and 15 represent the image-side surfaces of the same lenses, respectively.
[0171] Based on the data in Tables 1 and 2, the optical parameters of the large-area wide-angle TOF lens of this embodiment were simulated using the optical simulation software Zemax, and it was found that it satisfies the following parameters:
[0172] Aperture F / 1.4, full field of view 115°, sensor size: 1 / 1.7 inch, working distance: 5m to infinity.
[0173] like Figure 2 The large-area wide-angle TOF lens of this utility model has uniform image point size in each field of view, and the average image spot RMS radius is less than 3.5mm, which can meet the requirement of a single pixel size smaller than that of TOF sensors on the market.
[0174] like Figure 3 The large-area wide-angle TOF lens of this utility model embodiment has good relative illumination, which is greater than 48%.
[0175] like Figure 4 The large-area wide-angle TOF lens of this utility model has small axial aberration and well controlled spherical aberration. The magnitude of the transverse aberration is within ±0.03mm, which is beneficial to improving the imaging quality.
[0176] like Figure 5 The large-area wide-angle TOF lens of this utility model embodiment has good resolution, with a full field-of-view resolution of 150 lp / mm > 0.35.
[0177] like Figure 6 The large-area wide-angle TOF lens of this utility model has a small MTF field curvature at 50lp / mm defocus across the entire frequency range, good MTF curve concentration, and an MTF peak value greater than 89%, resulting in good image quality for most TOF sensors.
[0178] The large-area wide-angle TOF lens in this embodiment of the invention has the following advantages:
[0179] 1. A large-area wide-angle TOF lens according to an embodiment of this utility model reduces the angle of large-angle incident light by means of a first lens group. The object-side surface of the meniscus lens in the first lens group is convex, which can reduce the angle of incidence of large-angle light relative to the lens, thereby effectively reducing the introduction of higher-order aberrations and better controlling tolerances. The symmetrical lens group uses two symmetrically arranged meniscus lenses with positive optical power. The object-side surface of the meniscus lens near the object plane is concave, and the image-side surface is convex. The meniscus lens near the image plane in the symmetrical lens group... The object side of the lens is convex, and the image side is concave. This symmetrical lens group with a symmetrical structure adopts a similar principle to a double Gaussian lens structure, which can effectively correct aberrations such as spherical aberration and coma. Finally, the aberrations of the beam are further corrected by the meniscus lens with positive optical power and the biconvex lens with positive optical power in the second lens group, which are located close to the image plane, to meet the image quality requirements. With the above arrangement, high-quality imaging with a large target surface and a wide angle of view can be achieved by using spherical lenses in the entire lens, without the need to use aspherical lenses, thereby greatly reducing the cost of the lens.
[0180] 2. By combining the optical power of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7, and by reasonably setting the position of the aperture stop STO and the air gap between each optical component, a large target surface (φ9.5mm) and a large field of view (FOV115°) effect are achieved. The large field of view detection is conducive to capturing more spatial information.
[0181] 3. Using low-cost spherical lenses results in more stable high and low temperature performance of the lens and is more conducive to cost control during the trial production stage.
[0182] While embodiments of the present invention have been described above in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and all such modifications and variations fall within the scope defined by the appended claims.
Claims
1. A large target wide-angle TOF lens, characterized in that, The lens includes a first lens group, a symmetric lens group and a second lens group arranged in order from an object plane to an image plane; The first lens group includes several meniscus lenses with negative focal length and convex object side surface, for reducing the incident light angle; The symmetric lens group includes two meniscus lenses with positive focal length arranged symmetrically, the object side surface of the meniscus lens close to the object plane is concave, and the image side surface is convex, the object side surface of the meniscus lens close to the image plane is convex, and the image side surface is concave; The second lens group includes several meniscus lenses with positive focal length and double convex lenses with positive focal length, for correcting the aberration of the light beam out of the symmetric lens group; The lens in the first lens group, the symmetric lens group and the second lens group is a spherical lens.
2. The large target wide-angle TOF lens according to claim 1, wherein, The first lens group includes a first lens (L1) and a second lens (L2), and the focal length of the first lens (L1) and the second lens (L2) satisfies the following conditions: -12 The symmetric lens group includes a third lens (L3) and a fourth lens (L4), and the focal length of the third lens (L3) and the fourth lens (L4) satisfies the following conditions:
3. A large target wide-angle TOF lens according to claim 2, characterized in that, 8 The second lens group includes a fifth lens (L5), a sixth lens (L6) and a seventh lens (L7), the fifth lens (L5) and the seventh lens (L7) are meniscus lenses with positive focal length, the sixth lens (L6) is a double convex lens with positive focal length, and the focal length of the fifth lens (L5), the sixth lens (L6) and the seventh lens (L7) satisfies the following conditions: 3 4. A large target wide-angle TOF lens according to claim 3, characterized in that, The refractive index of the first lens (L1), the second lens (L2), the third lens (L3), the fourth lens (L4), the fifth lens (L5), the sixth lens (L6) and the seventh lens (L7) satisfies the following conditions: 1.7 5. A large target wide-angle TOF lens according to claim 4, characterized in that, 6. A large target wide-angle TOF camera lens according to claim 4 or 5, characterized in that, A stop (STO) is arranged between the third lens (L3) and the fourth lens (L4).
7. A large target wide-angle TOF camera lens according to claim 6, wherein, The focal length ranges of the first lens (L1), the second lens (L2), the third lens (L3), the fourth lens (L4), the fifth lens (L5), the sixth lens (L6) and the seventh lens (L7) are-35.2500mm to-35.2600mm, -14.7500mm to 14.7600mm, 44.6200mm to 44.6300mm, 3046.3700mm to 3046.3800mm, 26.3300mm to 26.3400mm, 25.1900mm to 25.2000mm and 35.4700mm to 35.4800mm, respectively.
8. A large target wide-angle TOF lens according to claim 7, characterized in that, The radius of curvature of the object side surface of the first lens (L1) is 26.10mm to 26.20mm, and the radius of curvature of the image side surface of the first lens (L1) is 11.90mm to 12.00mm; The radius of curvature of the object side surface of the second lens (L2) is 58.30mm to 58.40mm, and the radius of curvature of the image side surface of the second lens (L2) is 7.70mm to 7.80mm; The radius of curvature of the object side surface of the third lens (L3) is-30.00mm to-30.10mm, and the radius of curvature of the image side surface of the third lens (L3) is-20.20mm to-20.30mm; The radius of curvature of the object side surface of the fourth lens (L4) is 19.50mm to 19.60mm, and the radius of curvature of the image side surface of the fourth lens (L4) is 16.40mm to 16.50mm; The radius of curvature of the object side surface of the fifth lens (L5) is 234.40mm to 234.50mm, and the radius of curvature of the image side surface of the fifth lens (L5) is-19.20mm to-19.30mm; The radius of curvature of the object side surface of the sixth lens (L6) is 21.60mm to 21.70mm, and the radius of curvature of the image side surface of the sixth lens (L6) is-37.80mm to-37.90mm; The radius of curvature of the object side surface of the seventh lens (L7) is 13.40mm to 13.50mm, and the radius of curvature of the image side surface of the seventh lens (L7) is 32.40mm to 32.50mm.
9. A large target wide-angle TOF lens according to claim 7, wherein, The distance from the object side surface of the first lens (L1) to the image side surface of the first lens (L1) is 5.60mm to 5.70mm; The distance from the image side surface of the first lens (L1) to the object side surface of the second lens (L2) is 11.45mm to 11.55mm; The distance from the object side surface of the second lens (L2) to the image side surface of the second lens (L2) is 9.10mm to 9.20mm; The distance from the image side surface of the second lens (L2) to the object side surface of the third lens (L3) is 4.10mm to 4.20mm; The distance from the image side surface of the second lens (L2) to the object side surface of the third lens (L3) is 4.10mm to 4.20mm; The distance from the object side surface of the third lens (L3) to the image side surface of the third lens (L3) is 7.96mm to 8.06mm; The distance from the image side surface of the third lens (L3) to the stop (STO) is 0.94mm to 1.04mm; The distance from the stop (STO) to the object side surface of the fourth lens (L4) is 1.16mm to 1.26mm; The distance from the object side surface of the fourth lens (L4) to the image side surface of the fourth lens (L4) is 6.84mm to 6.94mm; The distance from the image side surface of the fourth lens (L4) to the object side surface of the fifth lens (L5) is 2.24mm to 2.34mm; The distance from the object side surface of the fifth lens (L5) to the image side surface of the fifth lens (L5) is 2.75mm to 2.85mm; The distance from the image side surface of the fifth lens (L5) to the object side surface of the sixth lens (L6) is 2.70mm to 2.80mm; The distance from the object side surface of the sixth lens (L6) to the image side surface of the sixth lens (L6) is 4.30mm to 4.40mm; The distance from the image side surface of the sixth lens (L6) to the object side surface of the seventh lens (L7) is 2.80mm to 2.90mm; The distance from the object side surface of the seventh lens (L7) to the image side surface of the seventh lens (L7) is 8.25mm to 8.35mm; The distance from the image side surface of the seventh lens (L7) to the image plane is 3.84mm to 3.94mm.
10. A large target wide-angle TOF camera lens according to claim 1, wherein, The lenses in the first lens group, the symmetric lens group and the second lens group are coated with a broadband anti-reflection film with a transmittance of 99.3% to 99.7% for light with a wavelength of 400nm to 1100nm.