Laser radar transmitting lens

Abstract

This invention provides a lidar transmitting lens comprising six lenses of optical power, arranged sequentially along the optical axis from the object side to the light source emitting surface: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens has negative optical power, with a convex emitting surface and a concave emitting surface. The second lens has negative optical power. The third lens has positive optical power, with a concave emitting surface and a convex emitting surface. The fourth lens has negative optical power, with a concave emitting surface and a concave emitting surface. The fifth lens has positive optical power, with a convex emitting surface and a convex emitting surface. The sixth lens has positive optical power, with a concave emitting surface and a convex emitting surface. This invention improves the emission quality of the lens, giving it one or more advantages such as miniaturization, low CRA (Cost Reduction Amount), a wide field of view, high emission quality, and high collimation performance.

Description

Technical Field

[0001] This invention relates to the technical field of lenses, and in particular to a laser radar transmitting lens. Background Technology

[0002] Today, lidar is widely used for detecting the three-dimensional coordinates and ranging of objects. A lidar system consists of a controller, a light source, and a receiver. The controller controls the light source to emit a light beam. When the beam encounters a target object, it undergoes diffuse reflection. The receiver receives the reflected beam and uses the information from both the emitted and reflected beams to determine relevant information about the target object, such as its distance, azimuth, altitude, speed, attitude, and even shape. LiDAR is widely used in autonomous vehicles, drones, autonomous robots, satellites, and rockets.

[0003] As a key component of lidar systems, the transmitting lens processes the emitted beam and the reflected light. With the ever-increasing performance requirements of lidar applications, the parameters of lidar transmitting lenses need to evolve towards larger apertures, wider fields of view, and miniaturization to meet the growing demands for high-precision, wide-coverage detection. Current lidar transmitting lenses suffer from the problem of incompatibility between a large field of view, high emission quality, and high collimation performance, failing to meet market demands. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a laser radar transmitting lens that has the advantages of high transmission quality and high collimation performance.

[0005] The technical solution adopted in this invention is as follows: A lidar transmitting lens has six lenses with optical power, which are arranged sequentially along the optical axis from the object side to the light source emitting surface, including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens; each of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens includes an incident light surface near the light source emitting surface and an exit light surface near the object side. The first lens has negative optical power, its light-emitting surface is convex, and its light-incident surface is concave. The second lens has negative optical power; The third lens has positive optical power, its light-emitting surface is concave, and its light-incident surface is convex. The fourth lens has negative optical power, and its light-emitting surface is concave, as is its light-incident surface. The fifth lens has positive optical power, its light-emitting surface is convex, and its light-incident surface is convex. The sixth lens has positive optical power, its light-emitting surface is concave, and its light-incident surface is convex. Among them, the true image height IH corresponding to the maximum field of view angle of the lidar emission lens, the effective focal length f of the lidar emission lens, and the maximum field of view angle FOV of the lidar emission lens satisfy: 57° < f×FOV / IH < 94°; the focal length f3 of the third lens and the focal length f6 of the sixth lens satisfy: 0.7 < f3 / f6 < 2.

[0006] Further preferably, the lidar emission lens satisfies one or more of the following conditional expressions: the total optical length TTL of the lidar emission lens and the effective focal length f of the lidar emission lens satisfy: 18 < TTL / f < 29; the total optical length TTL of the lidar emission lens and the true image height IH corresponding to the maximum field of view angle of the lidar emission lens satisfy: 7.4 < TTL / IH < 9.8.

[0007] Further preferably, the lidar emission lens satisfies one or more of the following conditional expressions: the maximum field of view angle FOV of the lidar emission lens and the aperture value Fno of the lidar emission lens satisfy: 110° < FOV / Fno < 150°; the true image height IH corresponding to the maximum field of view angle of the lidar emission lens and the entrance pupil diameter EPD of the lidar emission lens satisfy: 3 < IH / EPD < 5.2; the true image height IH corresponding to the maximum field of view angle of the lidar emission lens and the effective focal length f of the lidar emission lens satisfy: 2 < IH / f < 3.3.

[0008] Further preferably, the lidar emission lens satisfies one or more of the following conditional expressions: the true image height IH corresponding to the maximum field of view angle of the lidar emission lens, the effective focal length f of the lidar emission lens, and the radian value θ of the maximum half field of view angle of the lidar emission lens satisfy: 0.67 < (IH / 2) / (f×θ) < 0.91; the true image height IH corresponding to the maximum field of view angle of the lidar emission lens and the radian value θ of the maximum half field of view angle of the lidar emission lens satisfy: 2.5mm < (IH / 2) / θ < 3.3mm.

[0009] Further preferably, the lidar emission lens satisfies one or more of the following conditional expressions: the focal length f1 of the first lens and the effective focal length f of the lidar emission lens satisfy: -7.1 < f1 / f < -4; the focal length f2 of the second lens and the effective focal length f of the lidar emission lens satisfy: -9.7 < f2 / f < -2.6; the focal length f5 of the fifth lens and the effective focal length f of the lidar emission lens satisfy: 3.6 < f5 / f < 5.1; the focal length f1 of the first lens and the focal length f6 of the sixth lens satisfy: -1.2 < f1 / f6 < -0.5; the focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy: -0.6 < f3 / f4 < -0.3.

[0010] Further preferably, the lidar emission lens satisfies one or more of the following conditional expressions: the focal length f3 of the third lens and the effective focal length f of the lidar emission lens satisfy: 6.2 < f3 / f < 12.3; the curvature radius R5 of the light-emitting surface of the third lens and the curvature radius R6 of the light-incident surface of the third lens satisfy: 9 < R5 / R6 < 27; the curvature radius R5 of the light-emitting surface of the third lens and the curvature radius R6 of the light-incident surface of the third lens satisfy: 0.7 < (R5 - R6) / (R5 + R6) < 1.

[0011] Further preferably, the lidar emission lens satisfies one or more of the following conditional expressions: the focal length f4 of the fourth lens and the effective focal length f of the lidar emission lens satisfy: -25 < f4 / f < -15; the curvature radius R7 of the light-emitting surface of the fourth lens and the curvature radius R8 of the light-incident surface of the fourth lens satisfy: -3.4 < R7 / R8 < -0.5; the curvature radius R7 of the light-emitting surface of the fourth lens and the curvature radius R8 of the light-incident surface of the fourth lens satisfy: -0.3 < (R7 + R8) / (R7 - R8) < 0.6.

[0012] Further preferably, the lidar emission lens satisfies one or more of the following conditional expressions: the focal length f6 of the sixth lens and the effective focal length f of the lidar emission lens satisfy: 3.9 < f6 / f < 12.5; the curvature radius R11 of the light-emitting surface of the sixth lens and the curvature radius R12 of the light-incident surface of the sixth lens satisfy: 1.7 < R11 / R12 < 2.8; the curvature radius R11 of the light-emitting surface of the sixth lens and the curvature radius R12 of the light-incident surface of the sixth lens satisfy: 0.2 < (R11 - R12) / (R11 + R12) < 0.5.

[0013] Further preferably, the lidar emission lens satisfies one or more of the following conditional expressions: the focal length f6 of the sixth lens and the combined focal length f456 of the fourth, fifth, and sixth lenses satisfy: 1.1 < f6 / f456 < 2.6; the focal length f3 of the third lens and the combined focal length f456 of the fourth, fifth, and sixth lenses satisfy: 1.4 < f3 / f456 < 2.6; the combined focal length f456 of the fourth, fifth, and sixth lenses and the effective focal length f of the lidar emission lens satisfy: 3.1 < f456 / f < 5.2.

[0014] Further preferably, the lidar emission lens satisfies one or more of the following conditional expressions: the true image height IH corresponding to the maximum field angle of the lidar emission lens, the effective focal length f of the lidar emission lens, and the maximum field angle FOV of the lidar emission lens satisfy: 63.93° < f×FOV / IH < 84.63°; the focal length f3 of the third lens and the focal length f6 of the sixth lens satisfy: 0.77 < f3 / f6 < 1.83.

[0015] The lidar emission lens provided by the present invention uses six lenses with specific optical powers. Through specific surface shape combinations and reasonable optical power distributions, it can improve the emission quality of the lens, reduce aberration, improve the emission quality of the lens, and make the lens have one or more advantages such as miniaturization, small CRA, large field angle, high emission quality, and high collimation performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 is a schematic structural diagram of the lidar emission lens in Embodiment 1 of the present invention.

[0017] Figure 2 is a field curvature curve diagram of the lidar emission lens in Embodiment 1 of the present invention.

[0018] Figure 3 is an axial aberration curve diagram of the lidar emission lens in Embodiment 1 of the present invention.

[0019] Figure 4 is an MTF curve diagram of the lidar emission lens in Embodiment 1 of the present invention.

[0020] Figure 5 is a schematic structural diagram of the lidar emission lens in Embodiment 2 of the present invention.

[0021] Figure 6This is a field curvature curve diagram of the laser radar transmitting lens in Embodiment 2 of the present invention.

[0022] Figure 7 This is an axial aberration curve of the laser radar transmitting lens in Embodiment 2 of the present invention.

[0023] Figure 8 This is an MTF curve of the laser radar transmitting lens in Embodiment 2 of the present invention.

[0024] Figure 9 This is a schematic diagram of the structure of the lidar transmitting lens in Embodiment 3 of the present invention.

[0025] Figure 10 This is a field curvature curve diagram of the laser radar transmitting lens in Embodiment 3 of the present invention.

[0026] Figure 11 This is an axial aberration curve of the laser radar transmitting lens in Embodiment 3 of the present invention.

[0027] Figure 12 This is an MTF curve of the laser radar transmitting lens in Embodiment 3 of the present invention.

[0028] Figure 13 This is a schematic diagram of the structure of the lidar transmitting lens in Embodiment 4 of the present invention.

[0029] Figure 14 This is a field curvature curve diagram of the laser radar transmitting lens in Embodiment 4 of the present invention.

[0030] Figure 15 This is an axial aberration curve of the laser radar transmitting lens in Embodiment 4 of the present invention.

[0031] Figure 16 This is an MTF curve of the laser radar transmitting lens in Embodiment 4 of the present invention.

[0032] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0033] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0034] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of the invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0035] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0036] In this paper, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region.

[0037] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0038] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so specified herein.

[0039] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] A lidar transmitting lens provided by an embodiment of the present invention transmits the emitted light beam to the object side. The lidar transmitting lens is disposed in the light-emitting direction of the light source, that is, the emitting surface of the light source emitting end is the light-emitting side of the optical signal. The number of lenses with optical power in the lidar transmitting lens is six. Along the optical axis from the object side to the light source emitting surface (in the reverse direction of the light transmission), it sequentially includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens; the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens each include an incident surface close to the light source emitting surface and an exit surface close to the object side. It can be understood that the surface of each lens close to the light source emitting surface is called the incident surface of the lens, and the surface of each lens close to the object side is called the exit surface of the lens.

[0041] In some embodiments, the first lens may have a negative optical power, its exit surface is convex, and its incident surface is concave. The second lens may have a negative optical power, its exit surface may be concave or convex, and its incident surface may be concave or convex. The third lens may have a positive optical power, its exit surface is concave, and its incident surface is convex. The fourth lens may have a negative optical power, its exit surface is concave, and its incident surface is concave. The fifth lens may have a positive optical power, its exit surface is convex, and its incident surface is convex. The sixth lens may have a positive optical power, its exit surface is concave, and its incident surface is convex.

[0042] In some embodiments, the lidar transmitting lens may further include an aperture stop, and the aperture stop may be located between the third lens and the fourth lens. It can be understood that the aperture stop can control the light beam transmission and correct aberrations.

[0043] In some embodiments, the lidar transmitting lens may further include a filter, and the filter is disposed between the sixth lens and the light source emitting surface. The filter is used to filter out interfering light and prevent the interfering light from affecting the emission quality.

[0044] In some embodiments, the true image height IH corresponding to the maximum field angle of the lidar transmitting lens, the effective focal length f of the lidar transmitting lens, and the maximum field angle FOV of the lidar transmitting lens satisfy: 57° < f × FOV / IH < 94°. Meeting the above range, by reasonably restricting the relationship between the focal length, field angle, and image height of the lens, the lens has good optical performance. More specifically, 63.93° < f × FOV / IH < 84.63°.

[0045] In some embodiments, the focal length f3 of the third lens and the focal length f6 of the sixth lens satisfy: 0.7 < f3 / f6 < 2. Meeting the above range can avoid excessive light deflection, is beneficial to the smooth transition of light, and reduces the difficulty of aberration correction. More specifically, 0.77 < f3 / f6 < 1.83.

[0046] In some embodiments, the total optical length TTL of the lidar emission lens and the effective focal length f of the lidar emission lens satisfy: 18 < TTL / f < 29; the total optical length TTL of the lidar emission lens and the true image height IH corresponding to the maximum field of view angle of the lidar emission lens satisfy: 7.4 < TTL / IH < 9.8. Meeting the above ranges, by reasonably controlling the total length, focal length, and image height of the lidar emission lens, it helps the lidar emission lens to achieve a balance between the total length and volume, and is conducive to improving the structural stability of the lidar emission lens. More specifically, 19.69 < TTL / f < 26.16, 8.16 < TTL / IH < 8.9.

[0047] In some embodiments, the maximum field of view angle FOV of the lidar emission lens and the aperture value Fno of the lidar emission lens satisfy: 110° < FOV / Fno < 150°. Meeting the above conditions is conducive to expanding the field of view angle of the lens and increasing the aperture of the lens, realizing the wide-angle and large-aperture characteristics of the lens. The wide-angle characteristic can meet the requirements of large-range detection. More specifically, 124.9° < FOV / Fno < 134.3°.

[0048] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the lidar emission lens and the entrance pupil diameter EPD of the lidar emission lens satisfy: 3 < IH / EPD < 5.2. Meeting the above conditions makes the field of view and light flux balanced and improves the laser emission efficiency. More specifically, 3.39 < IH / EPD < 4.76.

[0049] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the lidar emission lens and the effective focal length f of the lidar emission lens satisfy: 2 < IH / f < 3.3. Meeting the above range, by reasonably controlling the ratio of the image height and focal length of the lens, the ultra-wide-angle characteristic is realized. More specifically, 2.26 < IH / f < 2.98.

[0050] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the lidar emission lens, the effective focal length f of the lidar emission lens, and the radian value θ of the maximum half field of view angle of the lidar emission lens satisfy: 0.67 < (IH / 2) / (f×θ) < 0.91. Meeting the above conditions can better achieve small distortion and obtain more accurate ranging data.

[0051] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the lidar emission lens and the radian value θ of the maximum half field of view angle of the lidar emission lens satisfy: 2.5mm < (IH / 2) / θ < 3.3mm. Meeting the above conditions can balance the size of the field of view angle and the image height. More specifically, 2.76mm < (IH / 2) / θ < 2.99mm.

[0052] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the lidar emission lens satisfy: -7.1 < f1 / f < -4. Meeting the above range, the first lens receives light rays entering the lens at a large angle, expands the field angle range of the lens, and is also conducive to reducing the sensitivity of the lens to achieve a miniaturized design of the lens. More specifically, -6.48 < f1 / f < -4.47.

[0053] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the lidar emission lens satisfy: -9.7 < f2 / f < -2.6. Meeting the above range, the second lens has a negative focal length and can perform a second adjustment on the full-field light beam and a second emission on the large-field light beam, which is conducive to achieving a large field of view of the lens. More specifically, -8.81 < f2 / f < -2.88.

[0054] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the lidar emission lens satisfy: 3.6 < f5 / f < 5.1. Meeting the above conditions, the fifth lens is conducive to light convergence, can improve the collimation effect of the laser, and reduce the exit angle of the lens. More specifically, 4.01 < f5 / f < 4.66.

[0055] In some embodiments, the focal length f1 of the first lens and the focal length f6 of the sixth lens satisfy: -1.2 < f1 / f6 < -0.5. Meeting the above range, by reasonably setting the focal lengths of the first and last lenses, it is ensured that as much light as possible enters the system to achieve a high relative illumination of the lens. More specifically, -1.05 < f1 / f6 < -0.55.

[0056] In some embodiments, the focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy: -0.6 < f3 / f4 < -0.3. Meeting the above conditions, the aberration of the lidar emission lens can be further compensated and adjusted to achieve a high imaging performance of the lidar emission lens. More specifically, -0.5 < f3 / f4 < -0.34.

[0057] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the lidar emission lens satisfy: 6.2 < f3 / f < 12.3; the radius of curvature R5 of the light-emitting surface of the third lens and the radius of curvature R6 of the light-incident surface of the third lens satisfy: 9 < R5 / R6 < 27; the radius of curvature R5 of the light-emitting surface of the third lens and the radius of curvature R6 of the light-incident surface of the third lens satisfy: 0.7 < (R5 - R6) / (R5 + R6) < 1. Satisfying the above ranges, the third lens has a positive focal length and a suitable surface shape, which is conducive to the smooth transition of light, facilitates the correction of astigmatism and field curvature, improves the emission quality of the lidar emission lens, and ensures the stability of the optical system. More specifically, 6.86 < f3 / f < 11.16; 9.88 < R5 / R6 < 24.7; 0.81 < (R5 - R6) / (R5 + R) < 0.93.

[0058] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the lidar emission lens satisfy: -25 < f4 / f < -15; the radius of curvature R7 of the light-emitting surface of the fourth lens and the radius of curvature R8 of the light-incident surface of the fourth lens satisfy: -3.4 < R7 / R8 < -0.5; the radius of curvature R7 of the light-emitting surface of the fourth lens and the radius of curvature R8 of the light-incident surface of the fourth lens satisfy: -0.3 < (R7 + R8) / (R7 - R8) < 0.6. Satisfying the above ranges, the fourth lens has a negative focal length and a suitable surface shape, which is conducive to the smooth transition of light, facilitates the correction of astigmatism and field curvature, improves the emission quality of the lidar emission lens, and ensures the stability of the optical system. More specifically, -22.69 < f4 / f < -17.1; -3.09 < R7 / R8 < -0.57; -0.27 < (R7 + R8) / (R7 - R8) < 0.52.

[0059] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the lidar emission lens satisfy: 3.9 < f6 / f < 12.5; the radius of curvature R11 of the light-emitting surface of the sixth lens and the radius of curvature R12 of the light-incident surface of the sixth lens satisfy: 1.7 < R11 / R12 < 2.8; the radius of curvature R11 of the light-emitting surface of the sixth lens and the radius of curvature R12 of the light-incident surface of the sixth lens satisfy: 0.2 < (R11 - R12) / (R11 + R12) < 0.5. Satisfying the above conditions, the sixth lens has a positive optical power and a suitable surface shape, which is conducive to the convergence of light, can improve the collimation effect on the laser, and reduce the exit angle of the lens. More specifically, 4.3 < f6 / f < 11.14; 1.86 < R11 / R12 < 2.49; 0.29 < (R11 - R12) / (R11 + R12) < 0.44.

[0060] In some embodiments, the focal length f6 of the sixth lens and the combined focal length f456 of the fourth, fifth, and sixth lenses satisfy: 1.1 < f6 / f456 < 2.6; the focal length f3 of the third lens and the combined focal length f456 of the fourth, fifth, and sixth lenses satisfy: 1.4 < f3 / f456 < 2.6; the focal length f4 of the fourth lens and the combined focal length f456 of the fourth, fifth, and sixth lenses satisfy: -7.1 < f4 / f456 < -3.3. Meeting the above ranges increases the area of light entering the imaging surface, which is beneficial for achieving large image surface imaging of the lens. At the same time, it increases the light input and improves the relative illumination of the system. More specifically, 1.23 < f6 / f456 < 2.35; 1.58 < f3 / f456 < 2.36; -6.4 < f4 / f456 < -3.68.

[0061] In some embodiments, the combined focal length f456 of the fourth, fifth, and sixth lenses and the effective focal length f of the lidar emission lens satisfy: 3.1 < f456 / f < 5.2. Meeting the above range is beneficial for balancing the distortion and astigmatism generated by the front lens of the lidar emission lens by reasonably setting the optical power of the rear lens group of the aperture, thus improving the emission quality of the lidar emission lens. More specifically, 3.47 < f456 / f < 4.76.

[0062] In some embodiments, the distance BL on the optical axis from the light incident surface of the sixth lens to the light source emission surface and the effective focal length f of the lidar emission lens satisfy: 2 < BL / f < 3.9. Meeting the above conditions is beneficial for achieving a short back focal length of the lens, and is beneficial for miniaturizing the lens while ensuring sufficient space for the installation of optical elements. More specifically, 2.16 < BL / f < 3.67.

[0063] In some embodiments, the curvature radius R5 of the light exit surface of the third lens and the effective focal length f of the lidar emission lens satisfy: -140 < R5 / f < -60; the curvature radius R6 of the light incident surface of the third lens and the effective focal length f of the lidar emission lens satisfy: -7.6 < R6 / f < -4. Meeting the above ranges is beneficial for the smooth transition of light, facilitating the correction of astigmatism and field curvature, improving the emission quality of the lidar emission lens, and ensuring the stability of the optical system. More specifically, -124.66 < R5 / f < -68.19; -6.91 < R6 / f < -4.4.

[0064] In some embodiments, the radius of curvature R7 of the light-emitting surface of the fourth lens and the effective focal length f of the lidar emission lens satisfy: -83 < R7 / f < -20; the radius of curvature R8 of the light-incident surface of the fourth lens and the effective focal length f of the lidar emission lens satisfy: 21 < R8 / f < 44. Meeting the above ranges, the fourth lens has a suitable surface shape, which is conducive to the smooth transition of light, facilitates the correction of astigmatism and field curvature, improves the emission quality of the lidar emission lens, and ensures the stability of the optical system. More specifically, -74.28 < R7 / f < -22.24; 24.13 < R8 / f < 39.59.

[0065] In some embodiments, the radius of curvature R11 of the light-emitting surface of the sixth lens and the effective focal length f of the lidar emission lens satisfy: -15 < R11 / f < -4.5; the radius of curvature R12 of the light-incident surface of the sixth lens and the effective focal length f of the lidar emission lens satisfy: -6.5 < R12 / f < -2.2. Meeting the above conditions is conducive to the convergence of light, thereby adjusting the trend of the marginal beam and ensuring that the lens has high collimation performance. More specifically, -13.43 < R11 / f < -5.1; -5.91 < R12 / f < -2.52.

[0066] In some embodiments, the lidar emission lens satisfies the following conditional expressions: 1.4 mm < f < 2.3 mm; 0.95 mm < EPD < 1.55 mm; 37 mm < TTL < 45 mm; 1.3 < Fno < 1.7; 2.5° < CRA < 4.3°; 4.4 mm < BL < 6.2 mm; 175° < FOV < 220°; 4.6 mm < IH < 5 mm. In the above conditional expressions, f represents the effective focal length of the lidar emission lens, EPD represents the entrance pupil diameter of the lidar emission lens, TTL represents the total optical length of the lidar emission lens, Fno represents the aperture value of the lidar emission lens, CRA represents the principal ray incident angle at the maximum image height of the lidar emission lens, BL represents the distance from the light-incident surface of the sixth lens to the light source emission surface on the optical axis, FOV represents the maximum field angle of the lidar emission lens, and IH represents the true image height corresponding to the maximum field angle of the lidar emission lens. Meeting the above ranges, the lidar emission lens has at least one or more advantages such as miniaturization, large aperture, large field angle, and small CRA. More specifically, 1.62 mm < f < 2.14 mm; 1.01 mm < EPD < 1.43 mm; 39.49 mm < TTL < 43.01 mm; 1.39 < Fno < 1.61; 2.7° < CRA < 4.09°; 4.61 mm < BL < 6.02 mm; 185° < FOV < 201°; 4.83 mm < IH < 4.85 mm.

[0067] In some embodiments, the lens material of the lidar transmitting lens provided by the present invention can be glass or plastic. When the lens is made of plastic, production costs can be effectively reduced. Alternatively, when the lens is made of glass, the low dispersion characteristic of glass itself can effectively correct the geometric chromatic aberration of the optical system. The lens provided by the present invention can adopt an all-glass lens structure, which can reduce dispersion, effectively correct chromatic aberration of the lens, and improve transmission quality.

[0068] In some embodiments, the first, second, third, fourth, fifth, and sixth lenses can be spherical or aspherical lenses. Compared to spherical structures, aspherical structures can effectively reduce aberrations in the optical system, thereby reducing the number of lenses and their size, and better achieving lens miniaturization. More specifically, the first, second, third, fourth, and fifth lenses of this invention are spherical lenses, while the sixth lens can be an aspherical lens.

[0069] In various embodiments of the present invention, when an aspherical lens is used, the shapes of each aspherical surface of the lidar transmitting lens satisfy the following equations: ; Where z is the distance between the surface and the vertex of the surface in the direction of the optical axis, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, K is the quadratic surface coefficient, and B, C, D, E, and F are the fourth, sixth, eighth, tenth, and twelfth order surface coefficients, respectively.

[0070] The present invention will be further described below with reference to several embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the lens are different; for specific differences, please refer to the parameter tables of each embodiment. The following embodiments are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention.

[0071] Example 1

[0072] Please see Figure 1The diagram shows a schematic of the structure of a lidar emitting lens 100 provided in Embodiment 1 of the present invention. The lidar emitting lens 100 transmits the emitted light beam to the object side. The lidar emitting lens 100 is located in the light-emitting direction of the light source, that is, the emitting surface of the light source is the light-emitting side. The lidar emitting lens 100 includes, along the optical axis from the object side to the light source emitting surface S9 (in the opposite direction of light transmission): a first lens L1, a second lens L2, a third lens L3, an aperture ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a filter G1. Each 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 filter G1 includes an incident surface and an emitting surface, which are disposed opposite to each other on the surface of each lens. It can be understood that the surface of each lens near the light source emitting surface is called the incident surface of the lens, and the surface of each lens near the object side is called the emitting surface of the lens.

[0073] Among them, the first lens L1 has negative optical power, its light-emitting surface S1 is convex, and its light-incident surface S2 is concave. The second lens L2 has negative optical power, its light-exiting surface S3 is concave, and its light-incident surface S4 is convex. The third lens L3 has positive optical power, its light-emitting surface S5 is concave, and its light-incident surface S6 is convex. The fourth lens L4 has negative optical power, its light-exiting surface S7 is concave, and its light-incident surface S8 is concave. The fifth lens L5 has positive optical power, its light-exiting surface S9 is convex, and its light-incident surface S10 is convex. The sixth lens L6 has positive optical power, its light-exiting surface S11 is concave, and its light-incident surface S12 is convex. The light-emitting surface S13 and the light-incident surface S14 of the filter G1 are both planar.

[0074] The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are glass spherical lenses; the sixth lens L6 is a glass aspherical lens.

[0075] The relevant parameters of each lens in the lidar transmitting lens 100 in Example 1 are shown in Table 1-1.

[0076] Table 1-1

[0077] The surface parameters of the aspherical lens of the lidar transmitting lens 100 in Example 1 are shown in Table 1-2.

[0078] Table 1-2

[0079] In this embodiment, the field curvature curve, axial aberration curve, and MTF curve of the lidar emitting lens 100 are respectively as follows: Figure 2 , Figure 3 , Figure 4 As shown.

[0080] Figure 2 The field curvature curve of Example 1 is shown, which represents the degree of curvature of light in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within -0.02 mm to 0.06 mm, indicating that the lidar transmitting lens can effectively correct the field curvature.

[0081] Figure 3 The diagram shows the axial aberration curves for Example 1, representing the aberrations of each wavelength along the optical axis. The horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. The diagram shows that the axial aberration offset is controlled within -0.02 mm to 0.02 mm, indicating that the lidar transmitting lens can effectively correct axial aberrations.

[0082] Figure 4 The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the lens imaging modulation at different spatial frequencies in various fields of view. The horizontal axis represents spatial frequency (unit: lp / mm), and the vertical axis represents MTF value. As can be seen from the figure, the MTF value of this example is above 0.4 throughout the entire field of view. Within the range of 0–60 lp / mm, the MTF curve decreases smoothly and uniformly from the center to the edge of the field of view, exhibiting good imaging quality and good detail resolution at both low and high frequencies.

[0083] Example 2

[0084] Please see Figure 5 The figure shows a schematic diagram of the structure of the laser radar transmitting lens 200 provided in Embodiment 2 of the present invention. The main difference between this embodiment and Embodiment 1 is that: the light-emitting surface S3 of the second lens L2 is a convex surface; the light-incident surface S4 of the second lens L2 is a concave surface; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0085] The relevant parameters of each lens in the lidar transmitting lens 200 in Example 2 are shown in Table 2-1.

[0086] Table 2-1

[0087] The surface profile parameters of the aspherical lens of the lidar transmitting lens 200 in Example 2 are shown in Table 2-2.

[0088] Table 2-2

[0089] In this embodiment, the field curvature curve, axial aberration curve, and MTF curve of the lidar emitting lens 200 are respectively as follows: Figure 6 , Figure 7 , Figure 8 As shown.

[0090] from Figure 6 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within 0~0.06mm, indicating that the lidar transmitting lens can effectively correct the field curvature.

[0091] from Figure 7 As can be seen, the axial aberration offset is controlled within -0.01mm to 0.05mm, indicating that the lidar transmitting lens can effectively correct axial aberration.

[0092] from Figure 8 As can be seen, the MTF value of this embodiment is above 0.3 throughout the entire field of view. In the range of 0 to 60 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions.

[0093] Example 3

[0094] Please see Figure 9 The figure shown is a schematic diagram of the structure of the laser radar transmitting lens 300 provided in Embodiment 3 of the present invention. The main difference between this embodiment and Embodiment 1 is that the light incident surface S4 of the second lens L2 is concave; the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0095] The relevant parameters of each lens in the lidar transmitting lens 300 in Example 3 are shown in Table 3-1.

[0096] Table 3-1

[0097] The surface profile parameters of the aspherical lens of the lidar transmitting lens 300 in Example 3 are shown in Table 3-2.

[0098] Table 3-2

[0099] In this embodiment, the field curvature curve, axial aberration curve, and MTF curve of the lidar emitting lens 300 are respectively as follows: Figure 10 , Figure 11 , Figure 12 As shown.

[0100] from Figure 10 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.02mm to 0.04mm, indicating that the lidar transmitting lens can effectively correct the field curvature.

[0101] from Figure 11 As can be seen, the axial aberration offset is controlled within -0.01mm to 0.02mm, indicating that the lidar transmitting lens can effectively correct axial aberration.

[0102] from Figure 12 As can be seen, the MTF value of this embodiment is above 0.7 throughout the entire field of view. In the range of 0 to 60 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions.

[0103] Example 4

[0104] Please see Figure 13 The diagram shows a schematic of the structure of the laser radar transmitting lens 400 provided in Embodiment 4 of the present invention. The main difference between this embodiment and Embodiment 1 is that the light incident surface S4 of the second lens L2 is concave; the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0105] The relevant parameters of each lens in the lidar transmitting lens 400 in Example 4 are shown in Table 4-1.

[0106] Table 4-1

[0107] The surface profile parameters of the aspherical lens of the lidar transmitting lens 400 in Example 4 are shown in Table 4-2.

[0108] Table 4-2

[0109] In this embodiment, the field curvature curve, axial aberration curve, and MTF curve of the lidar emitting lens 400 are respectively as follows: Figure 14 , Figure 15 , Figure 16 As shown.

[0110] from Figure 14 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.02mm to 0.06mm, indicating that the lidar transmitting lens can effectively correct the field curvature.

[0111] from Figure 15As can be seen, the axial aberration offset is controlled within -0.01mm to 0.03mm, indicating that the lidar transmitting lens can effectively correct axial aberration.

[0112] from Figure 16 As can be seen, the MTF value of this embodiment is above 0.3 throughout the entire field of view. In the range of 0 to 60 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions.

[0113] Please refer to Table 5 for the optical characteristics corresponding to each of the above embodiments, including the effective focal length f of the lidar transmitting lens, the total optical length TTL, the aperture value Fno, the true image height IH corresponding to the maximum field of view, the maximum field of view FOV, the distance BL from the incident surface of the sixth lens to the emitting surface of the light source on the optical axis, and the values ​​corresponding to each conditional expression in each embodiment.

[0114] Table 5

[0115] In summary, the lidar transmitting lens provided by the present invention employs six lenses with specific optical power. Through specific surface shape matching and reasonable optical power distribution, it can improve the emission quality of the lens, reduce aberrations, and enhance the emission quality of the lens, giving the lens one or more advantages such as miniaturization, small CRA, large field of view, high emission quality, and high collimation performance.

[0116] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0117] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A lidar transmitting lens, comprising six lenses with optical power, characterized in that, It sequentially includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens from the object side to the light source emitting surface along the optical axis; the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens each include an incident light surface close to the light source emitting surface and an exit light surface close to the object side; The first lens has a negative optical power, its exit light surface is convex, and its incident light surface is concave; The second lens has a negative optical power; The third lens has a positive optical power, its exit light surface is concave, and its incident light surface is convex; The fourth lens has a negative optical power, its exit light surface is concave, and its incident light surface is concave; The fifth lens has a positive optical power, its exit light surface is convex, and its incident light surface is convex; The sixth lens has a positive optical power, its exit light surface is concave, and its incident light surface is convex; Wherein, the true image height IH corresponding to the maximum field angle of the lidar emission lens, the effective focal length f of the lidar emission lens, and the maximum field angle FOV of the lidar emission lens satisfy: 57° < f×FOV / IH < 94°; the focal length f3 of the third lens and the focal length f6 of the sixth lens satisfy: 0.7 < f3 / f6 < 2.

2. The lidar transmitting lens according to claim 1, characterized in that, The lidar emission lens satisfies one or more of the following conditional formulas: the total optical length TTL of the lidar emission lens and the effective focal length f of the lidar emission lens satisfy: 18 < TTL / f < 29; the total optical length TTL of the lidar emission lens and the true image height IH corresponding to the maximum field angle of the lidar emission lens satisfy: 7.4 < TTL / IH < 9.

8.

3. The lidar transmitting lens according to claim 1, characterized in that, The lidar emission lens satisfies one or more of the following conditional formulas: the maximum field angle FOV of the lidar emission lens and the aperture value Fno of the lidar emission lens satisfy: 110° < FOV / Fno < 150°; the true image height IH corresponding to the maximum field angle of the lidar emission lens and the entrance pupil diameter EPD of the lidar emission lens satisfy: 3 < IH / EPD < 5.2; the true image height IH corresponding to the maximum field angle of the lidar emission lens and the effective focal length f of the lidar emission lens satisfy: 2 < IH / f < 3.

3.

4. The lidar transmitting lens according to claim 1, characterized in that, The lidar emission lens satisfies one or more of the following conditional formulas: the true image height IH corresponding to the maximum field angle of the lidar emission lens, the effective focal length f of the lidar emission lens, and the radian value θ of the maximum half field angle of the lidar emission lens satisfy: 0.67 < (IH / 2) / (f×θ) < 0.91; the true image height IH corresponding to the maximum field angle of the lidar emission lens and the radian value θ of the maximum half field angle of the lidar emission lens satisfy: 2.5mm < (IH / 2) / θ < 3.3mm.

5. The lidar transmitting lens according to claim 1, characterized in that, The lidar emission lens satisfies one or more of the following conditional expressions: The focal length f1 of the first lens and the effective focal length f of the lidar emission lens satisfy: -7.1 < f1 / f < -4; The focal length f2 of the second lens and the effective focal length f of the lidar emission lens satisfy: -9.7 < f2 / f < -2.6; The focal length f5 of the fifth lens and the effective focal length f of the lidar emission lens satisfy: 3.6 < f5 / f < 5.1; The focal length f1 of the first lens and the focal length f6 of the sixth lens satisfy: -1.2 < f1 / f6 < -0.5; The focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy: -0.6 < f3 / f4 < -0.

3.

6. The lidar transmitting lens according to claim 1, characterized in that, The lidar emission lens satisfies one or more of the following conditional expressions: The focal length f3 of the third lens and the effective focal length f of the lidar emission lens satisfy: 6.2 < f3 / f < 12.3; The radius of curvature R5 of the light-emitting surface of the third lens and the radius of curvature R6 of the light-incident surface of the third lens satisfy: 9 < R5 / R6 < 27; The radius of curvature R5 of the light-emitting surface of the third lens and the radius of curvature R6 of the light-incident surface of the third lens satisfy: 0.� < (R5 - R6) / (R5 + R6) < 1.

7. The lidar transmitting lens according to claim 1, characterized in that, The lidar emission lens satisfies one or more of the following conditional expressions: The focal length f4 of the fourth lens and the effective focal length f of the lidar emission lens satisfy: -25 < f4 / f < -15; The radius of curvature R7 of the light-emitting surface of the fourth lens and the radius of curvature R8 of the light-incident surface of the fourth lens satisfy: -3.4 < R7 / R8 < -0.5; The radius of curvature R7 of the light-emitting surface of the fourth lens and the radius of curvature R8 of the light-incident surface of the fourth lens satisfy: -0.3 < (R7 + R৮) / (R7 - R8) < 0.

6.

8. The lidar transmitting lens according to claim 1, characterized in that, The lidar emission lens satisfies one or more of the following conditional expressions: The focal length f6 of the sixth lens and the effective focal length f of the lidar emission lens satisfy: 3.9 < f6 / f < 12.5; The radius of curvature R11 of the light-emitting surface of the sixth lens and the radius of curvature R12 of the light-incident surface of the sixth lens satisfy: 1.7 < R11 / R12 < 2.8; The radius of curvature R11 of the light-emitting surface of the sixth lens and the radius of curvature R12 of the light-incident surface of the sixth lens satisfy: 0.2 < (R11 - R12) / (R11 + R12) < 0.

5.

9. The lidar transmitting lens according to claim 1, characterized in that, The lidar emission lens satisfies one or more of the following conditional expressions: The focal length f6 of the sixth lens and the combined focal length f456 of the fourth lens, the fifth lens, and the sixth lens satisfy: 1.1 < f6 / f456 < 2.6; The focal length f3 of the third lens and the combined focal length f456 of the fourth lens, the fifth lens, and the sixth lens satisfy: 1.4 < f3 / f456 < 2.6; The combined focal length f456 of the fourth lens, the fifth lens, and the sixth lens and the effective focal length f of the lidar emission lens satisfy: 3.1 < f456 / f < 5.

2.

10. The lidar transmitting lens according to claim 1, characterized in that, The lidar emission lens satisfies one or more of the following conditional expressions: The true image height IH corresponding to the maximum field angle of view of the lidar emission lens, the effective focal length f of the lidar emission lens, and the maximum field angle FOV of the lidar emission lens satisfy: 63.93° < f×FOV / IH < 84.63°; The focal length f3 of the third lens and the focal length f6 of the sixth lens satisfy: 0.77 < f3 / f6 < 1.83.

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