Large-target-surface wide-angle TOF lens

Abstract

The invention discloses a large-target-surface wide-angle TOF lens, and relates to the technical field of optical lenses, and the large-target-surface wide-angle TOF lens comprises a first lens group, a symmetric lens group and a second lens group. The first lens group comprises a plurality of meniscus lenses with negative focal power and convex object side surfaces, and the meniscus lenses are used for reducing incident light angles relative to the lenses; the symmetrical lens group comprises two meniscus lenses which are symmetrically arranged and have positive focal power, the object side surface of the meniscus lens close to the object plane in the symmetrical lens group is a concave surface, the image side surface of the meniscus lens close to the image plane in the symmetrical lens group is a convex surface, and the object side surface of the meniscus lens close to the image plane in the symmetrical lens group is a convex surface, and the image side surface of the meniscus lens close to the image plane in the symmetrical lens group is a concave surface; and the second lens group comprises a plurality of meniscus lenses with positive focal power and a biconvex lens with positive focal power, and is used for correcting aberration of emergent light beams of the symmetrical lens group. The lenses in the invention all adopt spherical lenses, so that high-quality imaging with large target surface and large visual angle can be realized, an aspherical mirror is not needed, and the lens cost is further greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of optical lenses, and in particular to a TOF lens with a large target surface and a wide angle. Background Art

[0002] Time of Flight (TOF) is a 3D vision sensing solution. It is rooted in depth sensor technology and uses a pixel array to obtain high-resolution depth distribution of the entire scene. It has the advantages of fast response time, high measurement accuracy, and strong anti-interference. TOF technology is used in mobile phones, automobiles, industry, face recognition, logistics, games, 3D printing, robots and other scenarios, and TOF lenses are an indispensable component. TOF lenses usually work in the near-infrared band and are composed of multiple lenses with large field of view, high illumination, and high resolution.

[0003] At present, for TOF lenses with large target surfaces, in order to achieve a small total track length (TTL), improve imaging quality, and reduce aberrations, most aspheric lenses are used. Whether it is a molded glass aspheric lens or an injection-molded plastic aspheric lens, the initial cost is high, which is not conducive to the development cost control in the trial production stage of TOF devices. Summary of the invention

[0004] In view of this, the present invention provides a large-target wide-angle TOF lens, which can overcome the technical problem in the prior art that large-target wide-angle TOF lenses require the use of aspherical lenses, resulting in high costs.

[0005] The invention provides a large-target-surface wide-angle TOF lens, comprising a first lens group, a symmetrical lens group and a second lens group which are sequentially arranged from an object plane to an image plane; the first lens group comprises a plurality of meniscus lenses with negative optical power and a convex object side surface, which are used to reduce the angle of incident light; the symmetrical lens group comprises two meniscus lenses with positive optical power which are symmetrically arranged, the object side surface of the meniscus lens close to the object plane in the symmetrical lens group is a concave surface, and the image side surface is a convex surface, and the object side surface of the meniscus lens close to the image plane in the symmetrical lens group is a convex surface, and the image side surface is a concave surface; the second lens group comprises a plurality of meniscus lenses with positive optical power and a biconvex lens with positive optical power, which are used to correct the aberration of a light beam emitted from the symmetrical lens group; wherein the lenses in the first lens group, the symmetrical lens group and the second lens group are all spherical lenses.

[0006] The invention discloses a large-target-surface wide-angle TOF lens. The first lens group reduces the angle of incident light at a large angle. The object side surface of the meniscus lens in the first lens group is a convex surface, which can reduce the incident angle of light at a large angle when it is incident on the lens, thereby effectively reducing the introduction of high-order aberrations and better controlling tolerances. The symmetrical lens group adopts two symmetrically arranged meniscus lenses with positive optical focal length. The object side surface of the meniscus lens close to the object plane is a concave surface, and the image side surface is a convex surface. The object side surface of the meniscus lens close to the image plane in the symmetrical lens group is a convex surface, and the image side surface is a concave surface. The symmetrical lens group with this symmetrical structure adopts a principle similar to a double Gaussian structure lens, which can better repair aberrations such as spherical aberration and coma. Finally, the meniscus lens with positive optical focal length in the second lens group and the double convex lens with positive optical focal length are used to approach the image plane position to further correct the aberration of the light beam to meet the image quality requirements. Through the above arrangement, the lenses in the entire lens all adopt spherical lenses to achieve high-quality imaging with a large target surface and a large viewing angle, without the need to adopt aspherical lenses, thereby greatly reducing the cost of the lens.

[0007] In an optional implementation, the first lens group includes a first lens and a second lens, and the focal lengths of the first lens and the second lens satisfy the following conditions:

[0008] -12<f1 / f<-5, -5<f2 / f<0

[0009] Among them, 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 target surface wide-angle TOF lens.

[0010] By stipulating that the focal length range of the first lens and the second lens in the first lens group is within the above range, the focus and angle of light can be precisely controlled, thereby optimizing the performance of the lens, helping to reduce the total optical length and improve imaging quality.

[0011] In an optional implementation, the symmetric lens group includes a third lens and a fourth lens, and the focal lengths of the third lens and the fourth lens satisfy the following conditions:

[0012] 8<f3 / f<15, 500<f4 / f<650

[0013] Among them, f3 is the focal length of the third lens, and f4 is the focal length of the fourth lens.

[0014] By stipulating the focal length range of the third lens and the fourth lens in the symmetrical lens group, it is helpful to further correct the light, reduce aberrations and improve the clarity of imaging.

[0015] In an optional implementation, the second lens group includes a fifth lens, a sixth lens and a seventh lens, the fifth lens and the seventh lens are both meniscus lenses with positive power, the sixth lens is a biconvex lens with positive power, and the focal lengths of the fifth lens, the sixth lens and the seventh lens satisfy the following conditions:

[0016] 3<f5 / f<8, 2<f6 / f<7, 4<f7 / f<9

[0017] Among them, 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 provision of the focal length range of the fifth lens, the sixth lens and the seventh lens in the second lens group helps to further correct aberrations and improve image quality. This design can optimize the optical performance of the lens to adapt it to different imaging requirements.

[0019] In an optional implementation, the refractive indices of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens satisfy the following conditions:

[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] Among them, 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 imaging quality of the lens.

[0023] In an optional implementation, a stop is provided between the third lens and the fourth lens.

[0024] By placing an aperture between the third and fourth lenses, you can control the amount of light entering the lens, helping to adjust the depth of field and aperture size, and optimize the exposure and contrast of the image.

[0025] In an optional embodiment, the focal length ranges of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are respectively -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.

[0026] By specifying the focal length range of each lens, the optical performance of the lens can be accurately controlled, and the imaging quality and adaptability of the lens can be improved.

[0027] In an optional 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 surface of the second lens is 58.30 mm to 58.40 mm, and the radius of curvature of the image side surface of the second lens is 7.70 mm to 7.80 mm;

[0029] The object-side surface of the third lens has a curvature radius of -30.00 mm to -30.10 mm, and the image-side surface of the third lens has a curvature radius of -20.20 mm to -20.30 mm;

[0030] The object-side surface of the fourth lens has a curvature radius of 19.50 mm to 19.60 mm, and the image-side surface of the fourth lens has a curvature radius of 16.40 mm to 16.50 mm;

[0031] The object-side surface of the fifth lens has a curvature radius of 234.40 mm to 234.50 mm, and the image-side surface of the fifth lens has a curvature radius of -19.20 mm to -19.30 mm;

[0032] The object side surface of the sixth lens has a curvature radius of 21.60 mm to 21.70 mm, and the image side surface of the sixth lens has a curvature radius of -37.80 mm to -37.90 mm;

[0033] The object-side surface of the seventh lens has a curvature radius of 13.40 mm to 13.50 mm, and the image-side surface of the seventh lens has a curvature radius of 32.40 mm to 32.50 mm.

[0034] By specifying the curvature radius of the object side and image side 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 authenticity of the image.

[0035] In an optional 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 surface of the first lens to the object side surface 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 surface of the second lens to the object side surface of the third lens is 4.10 mm to 4.20 mm;

[0039] The distance from the object side surface of the third lens to the image side surface 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 is 0.94mm to 1.04mm;

[0041] The distance from the aperture to the object side of the fourth lens is 1.16mm to 1.26mm;

[0042] The distance from the object side surface of the fourth lens to the image side surface of the fourth lens is 6.84 mm to 6.94 mm;

[0043] The distance between the image side surface of the fourth lens and the object side surface of the fifth lens is 2.24 mm to 2.34 mm;

[0044] A distance from the object side surface of the fifth lens to the image side surface of the fifth lens is 2.75 mm to 2.85 mm;

[0045] The distance between the image side surface of the fifth lens element and the object side surface of the sixth lens element is 2.70 mm to 2.80 mm;

[0046] The distance from the object side surface of the sixth lens to the image side surface of the sixth lens is 4.30 mm to 4.40 mm;

[0047] The distance between the image side surface of the sixth lens and the object side surface of the seventh lens is 2.80 mm to 2.90 mm;

[0048] The distance from the object side surface of the seventh lens to the image side surface of the seventh lens is 8.25 mm to 8.35 mm;

[0049] The distance from the image side surface of the seventh lens to the image plane 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 imaging quality of the lens.

[0051] In an optional embodiment, the lenses in the first lens group, the symmetrical 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.

[0052] By applying a broadband anti-reflection film, the transmittance of light within a specific wavelength range can be increased, and reflection and scattering can be reduced, thereby improving the optical efficiency and imaging quality of the lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0054] Figure 1 It is a schematic structural diagram of a large-target-area wide-angle TOF lens according to an embodiment of the present invention;

[0055] Figure 2 This is a point diagram of a large-target-area wide-angle TOF lens according to an embodiment of the present invention;

[0056] Figure 3 This is a relative illumination diagram of a large-target wide-angle TOF lens according to an embodiment of the present invention;

[0057] Figure 4 This is an axial aberration diagram of a large-target-area wide-angle TOF lens according to an embodiment of the present invention;

[0058] Figure 5 This is an MTF curve diagram of a large-target wide-angle TOF lens according to an embodiment of the present invention;

[0059] Figure 6 This is a 50LP / MM through-focus MTF diagram of the large-target wide-angle TOF lens according to an embodiment of the present invention.

[0060] Description of reference numerals:

[0061] L1-first lens; L2-second lens; L3-third lens; STO-aperture; L4-fourth lens; L5-fifth lens; L6-sixth lens; L7-seventh lens. DETAILED DESCRIPTION

[0062] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0063] In the description of the present invention, it should be noted that the term "several" means one or more. In addition, the terms "first", "second", "third" and the like are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0064] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0065] In the related technology, some small TOF lenses use 4G2P architecture, 1 / 4-inch sensor, and the maximum image height is φ4.5mm. Some wide-working-distance, large-aperture, wide-angle TOF lenses use 6G architecture, 1 / 3.6-inch sensor, and the maximum image height is φ5.3mm. The maximum image height of these TOF lenses cannot meet the imaging requirements of large target surfaces.

[0066] The design of a large-target wide-angle TOF lens means that the edge aberration is large, and optimizing the edge aberration is the key. At present, in order to improve the imaging quality of large-target wide-angle TOF lenses, related technologies use multiple aspherical lenses, which increases the cost of large-target wide-angle TOF lenses.

[0067] In view of this, the embodiment of the present invention proposes a large-target wide-angle TOF lens to optimize the existing TOF lens' small target surface, small field of view, and high trial production cost. In the embodiment of the present invention, multiple spherical lenses are used to correct off-axis aberrations, improve the lens MTF, and increase the field of view, thereby achieving low-cost trial production of lenses matching TOF devices.

[0068] See also Figure 1 The large-target-area wide-angle TOF lens of the embodiment of the present invention comprises a first lens group, a symmetrical lens group and a second lens group which are arranged in sequence from the object plane to the image plane; the first lens group comprises a plurality of meniscus lenses with negative optical power and a convex object side surface, which are used to reduce the angle of incident light; the symmetrical lens group comprises two meniscus lenses with positive optical power which are arranged symmetrically to each other, the object side surface of the meniscus lens close to the object plane in the symmetrical lens group is concave, and the image side surface is convex, the object side surface of the meniscus lens close to the image plane in the symmetrical lens group is convex, and the image side surface is concave; the second lens group comprises a plurality of meniscus lenses with positive optical power and a biconvex lens with positive optical power, which are used to correct the aberration of the light beam emitted through the symmetrical lens group; wherein 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, and the material of the spherical lenses is various types of glass, that is, the lenses in the embodiments 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-target-area wide-angle TOF lens of the embodiment of the present invention is 5m to infinity.

[0071] In the first lens group, the meniscus lens used has negative optical power, and the light passing through the first lens group is divergent.

[0072] In the symmetrical lens group, the meniscus lens used has positive focal power, and the light correction that occurs when the light passes through the symmetrical lens group is 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 lenses, which can better repair aberrations such as spherical aberration and coma.

[0073] The second lens group adopts a combination of a meniscus lens and a biconvex lens. Both the meniscus lens and the biconvex lens have positive optical power, which further converge the light beam to reduce the total length of the lens.

[0074] The embodiment of the present invention achieves an imaging target surface size of 9.5 mm, a lens FOV / 115° and an application band of 940 nm through the combination of the first lens group, the symmetrical lens group and the second lens group, which can ensure the imaging quality and use all glass spherical lenses with low manufacturing costs, better adapting to the requirements of large-size imaging targets for lenses.

[0075] A large-target-surface wide-angle TOF lens according to an embodiment of the present invention reduces the angle of incident light at a large angle through a first lens group. The object side surface of the meniscus lens in the first lens group is a convex surface, which can reduce the incident angle of large-angle light relative to the lens when it is incident on the lens, thereby effectively reducing the introduction of high-order aberrations and better controlling tolerances. The symmetrical lens group adopts two symmetrically arranged meniscus lenses with positive optical focal length, the object side surface of the meniscus lens close to the object plane is a concave surface, and the image side surface is a convex surface. The object side surface of the meniscus lens close to the image plane in the symmetrical lens group is a convex surface, and the image side surface is a concave surface. The symmetrical lens group of this symmetrical structure adopts a principle similar to a double Gaussian structure lens, which can better repair aberrations such as spherical aberration and coma. Finally, the meniscus lens with positive optical focal length in the second lens group and the double convex lens with positive optical focal length are close to the image plane position to further correct the aberration of the light beam to meet the image quality requirements. Through the above arrangement, the lenses in the entire lens all adopt spherical lenses to achieve high-quality imaging with a large target surface and a large viewing angle, without the need to use aspherical lenses, thereby greatly reducing the cost of the lens.

[0076] In an optional embodiment, the first lens group includes a first lens L1 and a second lens L2, and the focal lengths of the first lens L1 and the second lens L2 satisfy the following conditions: -12<f1 / f<-5, -5<f2 / f<0, wherein 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 surface wide-angle TOF lens.

[0077] The symmetric lens group includes a third lens L3 and a fourth lens L4, and the focal lengths of the third lens L3 and the fourth lens L4 satisfy the following condition: 8<f3 / f<15,500<f4 / f<650, wherein 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. The fifth lens L5 and the seventh lens L7 are both meniscus lenses with positive power. The sixth lens L6 is a biconvex lens with positive 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, wherein 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] Exemplarily, 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 having 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 within the above range, the focus and angle of the light can be precisely controlled, the light can be further corrected, the aberration can be reduced, and the imaging quality can be improved.

[0081] In an optional implementation, 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 conditions:

[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] Among them, 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] Exemplarily, 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 imaging quality of the lens.

[0086] In an optional implementation, a stop STO is provided between the third lens L3 and the fourth lens L4.

[0087] The aperture stop STO serves as the aperture stop STO of the optical system of the lens and is used to control the amount of light entering the entire lens.

[0088] An aperture stop STO is set between the third lens L3 and the fourth lens L4, which can control the amount of light entering the lens, help adjust the depth of field and aperture size, and optimize the exposure and contrast of the image.

[0089] In an optional implementation, 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 respectively -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.

[0090] In an example, 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 respectively -35.2500 mm, -14.7500 mm, 44.6200 mm, 3046.3700 mm, 26.3300 mm, 25.1900 mm and 35.4700 mm; or 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 respectively -35.2600 mm, 14.7600 mm, 44.6300 mm, 3046.3800 mm, 26.3400 mm, 25.2000 mm and 35.4800 mm.

[0091] By specifying the focal length range of each lens, the optical performance of the lens can be accurately controlled, and the imaging quality and adaptability of the lens can be improved.

[0092] In an optional embodiment, the radius of curvature of the object-side surface of the first lens L1 is 26.10 mm to 26.20 mm, and the radius of curvature of the image-side surface of the first lens L1 is 11.90 mm to 12.00 mm;

[0093] The object-side surface of the second lens L2 has a curvature radius of 58.30 mm to 58.40 mm, and the image-side surface of the second lens L2 has a curvature radius of 7.70 mm to 7.80 mm;

[0094] The object-side surface of the third lens L3 has a curvature radius of -30.00 mm to -30.10 mm, and the image-side surface of the third lens L3 has a curvature radius of -20.20 mm to -20.30 mm;

[0095] The object-side surface of the fourth lens L4 has a curvature radius of 19.50 mm to 19.60 mm, and the image-side surface of the fourth lens L4 has a curvature radius of 16.40 mm to 16.50 mm;

[0096] The object-side surface of the fifth lens L5 has a curvature radius of 234.40 mm to 234.50 mm, and the image-side surface of the fifth lens L5 has a curvature radius of -19.20 mm to -19.30 mm;

[0097] The object-side surface of the sixth lens L6 has a curvature radius of 21.60 mm to 21.70 mm, and the image-side surface of the sixth lens L6 has a curvature radius of -37.80 mm to -37.90 mm;

[0098] The radius of curvature of the object-side surface of the seventh lens L7 is 13.40 mm to 13.50 mm, and the radius of curvature of the image-side surface 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 surface of the first lens L1 is 26.10 mm, and the radius of curvature of the image-side surface of the first lens L1 is 11.90 mm;

[0100] The curvature radius of the object side surface of the second lens L2 is 58.30 mm, and the curvature radius of the image side surface of the second lens L2 is 7.70 mm;

[0101] The radius of curvature of the object side surface of the third lens L3 is -30.00 mm, and the radius of curvature of the image side surface of the third lens L3 is -20.20 mm;

[0102] The curvature radius of the object side surface of the fourth lens L4 is 19.50 mm, and the curvature radius of the image side surface of the fourth lens L4 is 16.40 mm;

[0103] The radius of curvature of the object side surface of the fifth lens L5 is 234.40 mm, and the radius of curvature of the image side surface of the fifth lens L5 is -19.20 mm;

[0104] The radius of curvature of the object side surface of the sixth lens L6 is 21.60 mm, and the radius of curvature of the image side surface of the sixth lens L6 is -37.80 mm;

[0105] The radius of curvature of the object-side surface of the seventh lens L7 is 13.40 mm, and the radius of curvature of the image-side surface of the seventh lens L7 is 32.40 mm.

[0106] In another example, the radius of curvature of the object-side surface of the first lens L1 is 26.20 mm, and the radius of curvature of the image-side surface of the first lens L1 is 12.00 mm;

[0107] The curvature radius of the object side surface of the second lens L2 is 58.40 mm, and the curvature radius of the image side surface of the second lens L2 is 7.80 mm;

[0108] The radius of curvature of the object side surface of the third lens L3 is -30.10 mm, and the radius of curvature of the image side surface of the third lens L3 is -20.30 mm;

[0109] The radius of curvature of the object side surface of the fourth lens L4 is 19.60 mm, and the radius of curvature of the image side surface of the fourth lens L4 is 16.50 mm;

[0110] The radius of curvature of the object side surface of the fifth lens L5 is 234.50 mm, and the radius of curvature of the image side surface of the fifth lens L5 is -19.30 mm;

[0111] The radius of curvature of the object side surface of the sixth lens L6 is 21.70 mm, and the radius of curvature of the image side surface of the sixth lens L6 is -37.90 mm;

[0112] The radius of curvature of the object-side surface of the seventh lens L7 is 13.50 mm, and the radius of curvature of the image-side surface of the seventh lens L7 is 32.50 mm.

[0113] By specifying the curvature radius of the object side and image side 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 authenticity of the image.

[0114] In an optional implementation, a 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 between the image side surface of the first lens L1 and the object side surface of the second lens L2 is 11.45 mm to 11.55 mm;

[0116] The distance between the object side surface of the second lens L2 and the image side surface of the second lens L2 is 9.10 mm to 9.20 mm;

[0117] The distance between the image side surface of the second lens L2 and the object side surface of the third lens L3 is 4.10 mm to 4.20 mm;

[0118] The distance between the object side surface of the third lens L3 and the image side surface of the third lens L3 is 7.96 mm to 8.06 mm;

[0119] The distance between the image side surface of the third lens L3 and the aperture stop STO is 0.94 mm to 1.04 mm;

[0120] The distance from the aperture STO to the object side surface of the fourth lens L4 is 1.16 mm to 1.26 mm;

[0121] A 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 between the image side surface of the fourth lens L4 and the object side surface of the fifth lens L5 is 2.24 mm to 2.34 mm;

[0123] A distance from the object side surface of the fifth lens L5 to the image side surface of the fifth lens L5 is 2.75 mm to 2.85 mm;

[0124] The distance between the image side surface of the fifth lens L5 and the object side surface of the sixth lens L6 is 2.70 mm to 2.80 mm;

[0125] A 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 between the image side surface of the sixth lens L6 and the object side surface of the seventh lens L7 is 2.80 mm to 2.90 mm;

[0127] The distance between the object side surface of the seventh lens L7 and the image side surface of the seventh lens L7 is 8.25 mm to 8.35 mm;

[0128] The distance from the image side surface to the image plane of the seventh lens L7 is 3.84 mm to 3.94 mm.

[0129] In one example, a 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 surface of the first lens L1 to the object side surface 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 between the image side surface of the second lens L2 and the object side surface 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 STO to the object side surface 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 between the image side surface of the fourth lens L4 and the object side surface of the fifth lens L5 is 2.24 mm;

[0138] The distance between the object side surface of the fifth lens L5 and the image side surface of the fifth lens L5 is 2.75 mm;

[0139] The distance between the image side surface of the fifth lens L5 and the object side surface of the sixth lens L6 is 2.70 mm;

[0140] The distance between the object side surface of the sixth lens L6 and the image side surface of the sixth lens L6 is 4.30 mm;

[0141] The distance between the image side surface of the sixth lens L6 and the object side surface of the seventh lens L7 is 2.80 mm;

[0142] The distance between the object side surface of the seventh lens L7 and the image side surface of the seventh lens L7 is 8.25 mm;

[0143] The distance from the image side surface to the image plane of the seventh lens L7 is 3.84 mm.

[0144] In another example, a 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 surface of the first lens L1 to the object side surface 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 between the image side surface of the second lens L2 and the object side surface 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 STO to the object side of the fourth lens L4 is 1.26 mm;

[0151] The distance between the object side surface of the fourth lens L4 and the image side surface of the fourth lens L4 is 6.94 mm;

[0152] The distance between the image side surface of the fourth lens L4 and the object side surface of the fifth lens L5 is 2.34 mm;

[0153] The distance between the object side surface of the fifth lens L5 and the image side surface of the fifth lens L5 is 2.85 mm;

[0154] The distance between the image side surface of the fifth lens L5 and 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 between the image side surface of the sixth lens L6 and the object side surface of the seventh lens L7 is 2.90 mm;

[0157] The distance between the object side surface of the seventh lens L7 and the image side surface of the seventh lens L7 is 8.35 mm;

[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 imaging quality of the lens.

[0160] In an optional embodiment, the lenses in the first lens group, the symmetrical 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.

[0161] By applying a broadband anti-reflection film, the transmittance of light within a specific wavelength range can be increased, and reflection and scattering can be reduced, thereby improving the optical efficiency and imaging quality of the lens.

[0162] Next, the beneficial effects of the large-target-area wide-angle TOF lens of the present invention are verified in combination with a preferred embodiment.

[0163] The large-target wide-angle TOF lens is fixedly provided with the first lens L1, the second lens L2, the third lens L3, the aperture STO, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7 and the target surface in sequence from the object surface to the image surface. 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 all spherical lenses, and the lens material is glass. Table 1 shows the focal length and selected materials of each lens in the large-target wide-angle TOF lens.

[0164] Table 1 Focal length and material parameters of the lens

[0165] Optical component name Focal length / mm Material First lens L1 -35.2522 D-LAF50-25 Second lens L2 -14.7519 H-LAK11 The third lens L3 44.6282 H-ZLAF92 The 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 the large-target wide-angle TOF lens are shown in Table 2.

[0167] Table 2 Lens curvature radius, thickness and surface type parameters

[0168]

[0169]

[0170] In Table 2, numbers 1, 3, 5, 8, 10, 12, and 14 are the object-side surfaces 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, respectively. In Table 2, numbers 2, 4, 6, 9, 11, 13, and 15 are the image-side surfaces 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, respectively.

[0171] According to the data in Table 1 and Table 2, the optical parameters of the large-target wide-angle TOF lens of the embodiment of the present invention are simulated by optical simulation software zemax, and it is found that it meets the following parameters:

[0172] Aperture F / 1.4, full field of view 115°, sensor size: 1 / 1.7inch, working distance: 5m~infinity.

[0173] like Figure 2 The image points of the large-target wide-angle TOF lens of the embodiment of the present invention are uniform in size in each field of view, and the average image spot RMS radius is less than 3.5mm, which can meet the demand of being smaller than the single pixel size of TOF sensors on the market.

[0174] like Figure 3 The large-target-area wide-angle TOF lens of the embodiment of the present invention has good relative illumination, and its relative illumination is greater than 48%.

[0175] like Figure 4 The large target surface wide-angle TOF lens of the embodiment of the present invention has small axial aberration, the spherical aberration is well controlled, and the size of the vertical axis aberration is within ±0.03mm, which is conducive to improving the imaging quality.

[0176] like Figure 5 The large-target wide-angle TOF lens of the embodiment of the present invention has good resolution, and the full-field resolution is 150lp / mm>0.35.

[0177] like Figure 6 The large-target wide-angle TOF lens of the embodiment of the present invention has a small field curvature corresponding to the full-frequency 50lp / mm defocus MTF, a good MTF curve concentration, and an MTF peak value greater than 89%. For most TOF sensors, the imaging quality is good.

[0178] The large-target-area wide-angle TOF lens in the embodiment of the present invention has the following advantages:

[0179] 1. A large-target-surface wide-angle TOF lens according to an embodiment of the present invention reduces the angle of incident light at a large angle through a first lens group. The object side surface of the meniscus lens in the first lens group is a convex surface, which can reduce the incident angle of large-angle light relative to the lens when it is incident on the lens, thereby effectively reducing the introduction of high-order aberrations and better controlling tolerances. The symmetrical lens group adopts two symmetrically arranged meniscus lenses with positive optical focal length, the object side surface of the meniscus lens close to the object plane is a concave surface, and the image side surface is a convex surface. The object side surface of the meniscus lens close to the image plane in the symmetrical lens group is a convex surface, and the image side surface is a concave surface. The symmetrical lens group of this symmetrical structure adopts a principle similar to a double Gaussian structure lens, which can better repair aberrations such as spherical aberration and coma. Finally, the meniscus lens with positive optical focal length and the double convex lens with positive optical focal length in the second lens group are close to the image plane position to further correct the aberration of the light beam to meet the image quality requirements. Through the above arrangement, the lenses in the entire lens all adopt spherical lenses to achieve high-quality imaging with a large target surface and a large viewing angle, without the need to use aspherical lenses, thereby greatly reducing the cost of the lens.

[0180] 2. Through the combination of 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, the position of the aperture STO and the air spacing between the optical components are reasonably set to achieve a large target surface (φ9.5mm) and a large field of view (FOV115°) effect. Detection with a large field of view is conducive to capturing more spatial information.

[0181] 3. Using low-cost spherical lenses, the lens's high and low temperature performance is more stable and is more conducive to cost control in the trial production stage.

[0182] Although the embodiments of the present invention are described above in conjunction with the drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A large-target-area wide-angle TOF lens, characterized in that: It includes a first lens group, a symmetrical lens group, and a second lens group which are sequentially arranged from the object plane to the image plane; The first lens group includes a plurality of meniscus lenses with negative optical power and a convex object side surface, which are used to reduce the angle of incident light; The symmetrical lens group comprises two symmetrically arranged meniscus lenses with positive focal power, the object side surface of the meniscus lens close to the object plane in the symmetrical lens group is concave, and the image side surface is convex, and the object side surface of the meniscus lens close to the image plane in the symmetrical lens group is convex, and the image side surface is concave; The second lens group includes a plurality of meniscus lenses with positive optical power and a biconvex lens with positive optical power, which are used to correct the aberration of the light beam emitted from the symmetrical lens group; Among them, the lenses in the first lens group, the symmetric lens group and the second lens group are all spherical lenses.

2. A TOF lens with a large target area and wide angle according to claim 1, characterized in that: The first lens group includes a first lens (L1) and a second lens (L2), and the focal lengths of the first lens (L1) and the second lens (L2) satisfy the following conditions: -12<f1 / f<-5, -5<f2 / f<0 Among them, 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 surface wide-angle TOF lens.

3. A TOF lens with a large target area and wide angle according to claim 2, characterized in that: The symmetric lens group includes a third lens (L3) and a fourth lens (L4), and 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 Wherein, f3 is the focal length of the third lens (L3), and f4 is the focal length of the fourth lens (L4).

4. The large-target-area wide-angle TOF lens according to claim 3, characterized in that: The second lens group includes a fifth lens (L5), a sixth lens (L6) and a seventh lens (L7), wherein the fifth lens (L5) and the seventh lens (L7) are both meniscus lenses with positive optical power, the sixth lens (L6) is a biconvex lens with positive optical power, and 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 Among them, 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).

5. The large-surface wide-angle TOF lens according to claim 4, characterized in that: 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 conditions: 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; 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).

6. A large-target-area wide-angle TOF lens according to claim 3, 4 or 5, characterized in that: A stop (STO) is provided between the third lens (L3) and the fourth lens (L4).

7. The large-surface wide-angle TOF lens according to claim 5, characterized in that: 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 respectively -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.

8. The large-surface 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 26.10 mm to 26.20 mm, and the radius of curvature of the image side surface of the first lens (L1) is 11.90 mm to 12.00 mm; The curvature radius of the object side surface of the second lens (L2) is 58.30 mm to 58.40 mm, and the curvature radius of the image side surface of the second lens (L2) is 7.70 mm to 7.80 mm; The radius of curvature of the object side surface of the third lens (L3) is -30.00 mm to -30.10 mm, and the radius of curvature of the image side surface of the third lens (L3) is -20.20 mm to -20.30 mm; The radius of curvature of the object side surface of the fourth lens (L4) is 19.50 mm to 19.60 mm, and the radius of curvature of the image side surface of the fourth lens (L4) is 16.40 mm to 16.50 mm; The radius of curvature of the object side surface of the fifth lens (L5) is 234.40 mm to 234.50 mm, and the radius of curvature of the image side surface of the fifth lens (L5) is -19.20 mm to -19.30 mm; The radius of curvature of the object side surface of the sixth lens (L6) is 21.60 mm to 21.70 mm, and the radius of curvature of the image side surface of the sixth lens (L6) is -37.80 mm to -37.90 mm; The radius of curvature of the object side surface of the seventh lens (L7) is 13.40 mm to 13.50 mm, and the radius of curvature of the image side surface of the seventh lens (L7) is 32.40 mm to 32.50 mm.

9. The large-surface wide-angle TOF lens according to claim 7, characterized in that: The distance between the object side surface of the first lens (L1) and the image side surface of the first lens (L1) is 5.60 mm to 5.70 mm; The distance between the image side surface of the first lens (L1) and the object side surface of the second lens (L2) is 11.45 mm to 11.55 mm; 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; The distance between the image side surface of the second lens (L2) and the object side surface of the third lens (L3) is 4.10 mm to 4.20 mm; 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; The distance between the image side surface of the third lens (L3) and the aperture stop (STO) is 0.94 mm to 1.04 mm; The distance between the aperture stop (STO) and the object side surface of the fourth lens (L4) is 1.16 mm to 1.26 mm; 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; The distance between the image side surface of the fourth lens (L4) and the object side surface of the fifth lens (L5) is 2.24 mm to 2.34 mm; The distance between the object side surface of the fifth lens (L5) and the image side surface of the fifth lens (L5) is 2.75 mm to 2.85 mm; The distance between the image side surface of the fifth lens (L5) and the object side surface of the sixth lens (L6) is 2.70 mm to 2.80 mm; 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; The distance between the image side surface of the sixth lens (L6) and the object side surface of the seventh lens (L7) is 2.80 mm to 2.90 mm; The distance from the object side surface of the seventh lens (L7) to the image side surface of the seventh lens (L7) is 8.25 mm to 8.35 mm; The distance from the image side surface to the image plane of the seventh lens (L7) is 3.84 mm to 3.94 mm.

10. The TOF lens with a large target area and wide angle according to claim 1, characterized in that: The lenses in the first lens group, the symmetrical lens group and the second lens group are all 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.

Images