Optical system, transceiver and lidar

Abstract

This invention relates to the field of lidar detection technology, providing an optical system, a transceiver, and a lidar. The optical system includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the optical axis from the object plane to the image plane. The first lens has negative refractive power, while the second, third, and fourth lenses all have positive refractive power. The first lens has a concave object-side surface and a convex image-side surface; the second lens has a concave object-side surface and a convex image-side surface; the third lens is a biconvex lens; and the fourth lens is a plano-convex lens with a convex object-side surface and a flat image-side surface. This invention also provides a transceiver and a lidar comprising the above-described optical system. The optical system, transceiver, and lidar provided by this invention have an increased field of view, enabling wide-angle detection.

Description

Technical Field

[0001] This invention belongs to the field of lidar detection technology, and particularly relates to an optical system, a transceiver device, and a lidar. Background Technology

[0002] LiDAR is a radar system that uses laser beams to detect the position, velocity, and other characteristics of a target. Its working principle is as follows: it emits a detection signal (laser beam) towards the target, and then compares the received signal reflected back from the target (target echo) with the emitted signal. After appropriate processing, it can obtain relevant information about the target, such as the target's distance, azimuth, altitude, speed, attitude, shape, and other parameters, thereby detecting, tracking, and identifying targets such as vehicles, aircraft, and missiles.

[0003] A typical lidar system consists of a transmitting module and a receiving module. The transmitting module includes a laser source and a transmitting optical system, while the receiving module includes a detector and a receiving optical system. However, current transmitting and / or receiving optical systems use optical systems with relatively small field of view, resulting in a small transmitting and / or receiving field of view for the lidar, which affects detection accuracy. Summary of the Invention

[0004] The purpose of this invention is to provide an optical system, transceiver, and lidar, which aims to solve the technical problem of small field of view of the optical systems used in the prior art for transmitting and / or receiving optical systems.

[0005] The present invention is implemented as follows: In a first aspect, an optical system is provided, the optical system comprising a first lens, a second lens, a third lens and a fourth lens arranged sequentially along the optical axis from the object plane to the image plane, wherein the first lens has negative refractive power, and the second lens, the third lens and the fourth lens all have positive refractive power;

[0006] The first lens has a concave object side and a convex image side; the second lens has a concave object side and a convex image side; the third lens is a biconvex lens; and the fourth lens is a plano-convex lens with a convex object side and a planar image side.

[0007] In an optional embodiment, the diameters of the first lens, the second lens, the third lens, and the fourth lens increase sequentially.

[0008] In an optional embodiment, the optical system satisfies the following relationship:

[0009] 1.5 <n1<1.6;2.0<n2<2.1;1.5<n3<1.6;1.8<n4<1.9;

[0010] Wherein, n1 is the refractive index of the first lens at a wavelength of 950nm, n2 is the refractive index of the second lens at a wavelength of 950nm, n3 is the refractive index of the third lens at a wavelength of 950nm, and n4 is the refractive index of the fourth lens at a wavelength of 950nm.

[0011] In an optional embodiment, the optical system has an optical path of 55-70mm, an effective focal length of 20-35mm, a field of view of 80-105°, and a back focal length of 0-4mm.

[0012] In a second aspect, a transceiver device is provided, the transceiver device including a transmitting module and a receiving module, the transmitting module including a laser light source and a transmitting optical system located on the light-emitting side of the laser light source, and the receiving module including a detector and a receiving optical system located on the light-incident side of the detector;

[0013] Wherein, at least one of the optical systems in the transmitting optical system and the receiving optical system is the optical system provided in the above embodiments.

[0014] In an optional embodiment, the transmitting module and the receiving module are arranged side by side with their optical axes parallel. The transceiver also includes a light-blocking plate located between the transmitting module and the receiving module, which is used to separate the light transmitted by the transmitting module and the receiving module respectively.

[0015] In an optional embodiment, the transceiver further includes a lens barrel, wherein the transmitting optical system, the receiving optical system, and the light-blocking plate are all disposed within the lens barrel.

[0016] In an optional embodiment, both the transmitting optical system and the receiving optical system have a light-transmitting region and a light-blocking region, wherein the light-blocking region is located at the edge of the optical system;

[0017] At least a portion of the non-light-transmitting area of ​​at least one optical system in the transmitting optical system and the receiving optical system is removed to form a planar structure on the outer wall of the optical system.

[0018] In an optional embodiment, the planar structure includes a first plane located between the optical axis of the transmitting optical system and the optical axis of the receiving optical system, and the first plane is set at a preset angle to the connecting line between the optical axis of the transmitting optical system and the optical axis of the receiving optical system.

[0019] In an optional embodiment, the planar structure further includes a second plane that corresponds one-to-one with the first plane, with the corresponding second plane and the first plane disposed on opposite sides of the same optical system.

[0020] In an optional embodiment, both the transmitting optical system and the receiving optical system employ the optical system described above, and the lens structures of the transmitting optical system and the receiving optical system are identical.

[0021] In an optional embodiment, the receiving optical system further includes a first aperture stop located between the third lens and the fourth lens;

[0022] And / or, the receiving optical system further includes a second aperture located between the fourth lens and the image plane.

[0023] In an optional embodiment, the transceiver further includes a filter located between the receiving optical system and the detector.

[0024] In an optional embodiment, the laser source and the detector are integrated on the same circuit board.

[0025] Thirdly, a lidar is provided, including the transceiver device provided in the above embodiments.

[0026] The technical advantages of this invention compared to existing technologies are as follows: The optical system provided in this embodiment includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the optical axis from the object plane to the image plane. The first lens has negative refractive power and is a meniscus lens; the second lens has positive refractive power and is also a meniscus lens; the third and fourth lenses both have positive refractive power and are respectively biconvex lenses and plano lenses. Through this structure, the overall optical path length, effective focal length, and back focal length of the optical system can be reduced compared to traditional lidar optical systems. This effectively reduces the size of the optical system and the lidar using the optical system provided in this embodiment. Simultaneously, it increases the field of view, enabling wide-angle light emission or reception, and simplifies the structural design of the optical system.

[0027] It is understood that the beneficial effects of the second and third aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the optical system provided in an embodiment of the present invention;

[0030] Figure 2 yes Figure 1 The diagram shows the optical system in use. Each lens in the diagram is a cross-sectional view, and the cross-sectional lines are not shown.

[0031] Figure 3 yes Figure 2 A schematic diagram of the back focal length of the optical system shown.

[0032] Figure 4 This is a schematic diagram of the transceiver device provided in an embodiment of the present invention, where the detector is not shown;

[0033] Figure 5 This is a schematic diagram of the transceiver device provided in another embodiment of the present invention, in which the laser source and detector are not shown;

[0034] Figure 6 yes Figure 4 or Figure 5 A schematic diagram of the optical path of the receiving optical system.

[0035] Explanation of reference numerals in the attached figures:

[0036] 100. Optical system; 110. First lens; 120. Second lens; 130. Third lens; 140. Fourth lens; 200. Transceiver; 210. Transmitting module; 211. Laser source; 212. Transmitting optical system; 220. Receiving module; 221. Detector; 222. Receiving optical system; 230. Light blocking plate; 240. Lens barrel; 260. Second plane; 270. First aperture; 271. Second aperture; 280. Filter; 290. Circuit board. Detailed Implementation

[0037] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0038] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0039] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0040] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0042] A lidar system consists of a transmitting module and a receiving module. The transmitting module includes a laser source and a transmitting optical system, while the receiving module includes a detector and a receiving optical system. The structures of the transmitting and receiving optical systems can be the same or different, depending on the desired light output and reception performance.

[0043] To address the problems existing in the aforementioned transmitting and / or receiving optical systems, an embodiment of the present invention provides an optical system. This optical system can be used as a transmitting optical system, a receiving optical system, or a shared optical system for both transmitting and receiving optical paths in a coaxial lidar, allowing for flexible selection based on specific application needs. When used as a transmitting optical system, the transmitting field of view can be increased; when used as a receiving optical system, the receiving field of view can be increased.

[0044] Please refer to Figure 1 and Figure 2 As shown, the optical system 100 includes a first lens 110, a second lens 120, a third lens 130, and a fourth lens 140 arranged sequentially along the optical axis from the object plane to the image plane. The first lens 110 has negative refractive power, with its object-side surface concave and its image-side surface convex. The second lens 120, third lens 130, and fourth lens 140 all have positive refractive power. The second lens 120 has a concave object-side surface and a convex image-side surface; the third lens 130 is a biconvex lens; and the fourth lens 140 is a plano-convex lens with a convex object-side surface and a planar image-side surface.

[0045] In this embodiment, the object-side surface and image-side surface of the first lens 110, the second lens 120, the third lens 130, and the fourth lens 140 can be spherical or aspherical, depending on the light output effect. Furthermore, the materials of the first lens 110, the second lens 120, the third lens 130, and the fourth lens 140 can be glass, plastic, or a glass-plastic composite material.

[0046] For ease of description, the following text will use optical system 100 as an example of a transmitting optical system to explain the structure and effects of optical system 100. It should be understood that when optical system 100 is used as a receiving optical system or as an optical system 100 shared by the transmitting and receiving optical paths in a coaxial lidar, its principle and effects are similar to those when optical system 100 is used as a transmitting optical system.

[0047] The working principle of the transmitting module of the optical system 100 provided in this embodiment of the invention is as follows:

[0048] like Figure 3 As shown, the distance from the outermost laser source 211 to the central optical axis of the optical system is y. The distance from the laser source 211 to the last lens (i.e., the fourth lens 140) is the back focal length (BFL) of the optical system 100. Assuming the divergence angle of the laser source 211 is θ and the aperture of the fourth lens 140 is D, in order to ensure the collimation efficiency of the optical system while also considering the lens aperture, according to the formula D = y + BFL * tan(θ / 2), the back focal length of the optical system should be minimized as much as possible.

[0049] In this embodiment, the fourth lens 140 is a plano-convex lens, which reduces the back focal length of the optical system 100 while ensuring that the entire beam emitted by the laser source 211 can pass through the optical system 100, thereby improving the collimation efficiency of the optical system 100.

[0050] In addition, the optical system 100 provided in this embodiment of the invention, besides the fourth lens 140 which is a plano-convex lens, also includes a first lens 110 and a second lens 120 which are meniscus lenses, and a third lens 130 which is a biconvex lens. These four lenses work together to reduce both the optical path length (EFL) and effective focal length (EFL) of the optical system 100 when the optical path length is 55-70 mm and the effective focal length is 20-35 mm. Simultaneously, the field of view can be increased to 80-105°, and the back focal length can be reduced from 60-80 mm to 0-4 mm. In the prior art, the optical path length of the optical system 100 is 120-150 mm, the effective focal length is 80-100 mm, and the field of view is 25°.

[0051] The optical system 100 provided in this embodiment of the invention includes a first lens 110, a second lens 120, a third lens 130, and a fourth lens 140 arranged sequentially along the optical axis from the object plane to the image plane. The first lens 110 has negative refractive power and is a meniscus lens; the second lens 120 has positive refractive power and is also a meniscus lens; the third lens 130 and the fourth lens 140 both have positive refractive power and are respectively biconvex lenses and plano lenses. Through this structure, the overall optical path of the optical system 100 can be reduced compared to the optical path, effective focal length, and back focal length of a conventional lidar optical system 100. This effectively reduces the size of the optical system 100 and the lidar using the optical system 100 provided in this embodiment, while increasing the field of view to achieve wide-angle light emission or reception, and simplifying the structural design of the optical system.

[0052] In use, the optical system is generally installed inside the lens barrel. For ease of installation, such as... Figure 1 and Figure 2 As shown, in an optional embodiment, the diameters of the first lens 110, the second lens 120, the third lens 130, and the fourth lens 140 increase sequentially.

[0053] Using the structure provided in this embodiment, each lens can be installed from one direction during installation, so as to ensure that the relative eccentricity of the optical axis and mechanical axis (i.e. the extension line of the center line of each lens) of the optical system 100 is small after installation. It also facilitates lens barrel processing and makes it easier to ensure the concentricity of the lens barrel.

[0054] To reduce the aberrations of the optical systems provided in the above embodiments, in an optional embodiment, the optical system satisfies the following relationship:

[0055] 1.5 <n1<1.6;2.0<n2<2.1;1.5<n3<1.6;1.8<n4<1.9;

[0056] Wherein, n1 is the refractive index of the first lens at a wavelength of 950nm, n2 is the refractive index of the second lens at a wavelength of 950nm, n3 is the refractive index of the third lens at a wavelength of 950nm, and n4 is the refractive index of the fourth lens at a wavelength of 950nm.

[0057] During the design process, by rationally designing the surface shape and refractive power of each lens, the optical system can satisfy the above-mentioned relationship, resulting in a smaller light spot size emitted by the optical system and satisfying a 45° field of view. When the above-mentioned lenses do not meet the above-mentioned refractive index range, the light focusing effect will be poor, which will lead to a larger light spot size emitted by the optical system or failure to satisfy a 45° field of view.

[0058] In addition, the optical systems provided in the various embodiments of the present invention do not include cylindrical mirrors. However, when in use, the optical system is generally installed inside the lens barrel, and a filter is set at the front end of the lens barrel. The laser light passing through the filter will be reflected. In order to reduce the adverse effects of the reflected light on the optical system, the influence of the cylindrical filter on the optical system can be corrected by optimizing the curvature radius and thickness of each lens in the optical system.

[0059] Please refer to Figure 4 As shown, in another embodiment of the present invention, a transceiver 200 is provided for use in lidar. The transceiver 200 includes a transmitting module 210 and a receiving module 220. The transmitting module 210 includes a laser source 211 and a transmitting optical system 212 located on the light-emitting side of the laser source 211. The receiving module 220 includes a detector and a receiving optical system 222 located on the light-incident side of the detector.

[0060] In this embodiment, at least one of the transmitting optical system 212 and the receiving optical system 222 is the optical system provided in the above embodiments. Specifically, in this embodiment, only the transmitting optical system 212 may use the optical system provided in the above embodiments, only the receiving optical system 222 may use the optical system provided in the above embodiments, or both the transmitting optical system 212 and the receiving optical system 222 may use the optical systems provided in the above embodiments. The specific choice can be made flexibly according to the usage requirements.

[0061] In this embodiment, the laser source 211 can be an array of light sources or a single light source, which can be flexibly selected according to the application requirements. When the laser source 211 is an array of light sources, the emitting module 210 is used to emit array lasers, which, in conjunction with the emitting optical system 212, can achieve wide-angle emission. In this case, the detectors are generally also multiple detectors arranged in an array to receive laser energy. In this embodiment, the receiving optical system 222 is used to converge laser energy from different fields of view.

[0062] The working principle of the transceiver 200 provided in this embodiment of the invention is as follows:

[0063] The laser source 211 emits laser light, which is collimated by the emitting optical system 212 and emitted onto the detection target. The target then reflects the laser light to form an echo signal. The echo signal is received by the receiving optical system 222 and focused onto the detector. The detector analyzes the echo signal and outputs corresponding data signals to an external data processing device. Finally, the data processing device outputs relevant detection data of the target, such as distance, speed, and shape.

[0064] At least one of the transmitting optical system 212 and the receiving optical system 222 in the transceiver device 200 provided in this embodiment of the invention is an optical system provided in the above embodiments. When the transmitting optical system 212 adopts the optical system provided in the above embodiments, the transmitting field of view can be increased and the collimation output efficiency of the laser light can be improved. When the receiving optical system 222 adopts the optical system provided in the above embodiments, the receiving field of view can be increased and the convergence energy of the echo light signal can be improved, ultimately achieving wide-angle detection and improving the detection accuracy of the transceiver device 200.

[0065] In existing technologies, to prevent light from entering the optical path of the receiving module and affecting the detection effect, a reflective structure is typically incorporated into the transceiver to increase the distance between the optical paths of the transmitting and receiving modules. This results in a longer light propagation time within the transceiver, a longer transmitting or receiving optical system, and consequently, a larger overall size of the transceiver. To avoid these problems, such as... Figure 5 As shown, in an optional embodiment, the transmitting module 210 and the receiving module 220 are arranged side by side with their optical axes parallel. The transceiver also includes a light-blocking plate 230. The light-blocking plate 230 is located between the transmitting module 210 and the receiving module 220 and is used to separate the light transmitted by the transmitting module 210 and the receiving module 220 respectively.

[0066] In this embodiment, the light-blocking sheet 230 can be an opaque sheet such as a metal sheet, plastic sheet, or rubber sheet. In use, the light-blocking sheet 230 can isolate the optical paths of the transmitting module 210 and the receiving module 220. Furthermore, since the optical paths of the transmitting module 210 and the receiving module 220 are parallel in this embodiment, after installing the light-blocking sheet 230, the two optical paths can transmit directly without the need for a reflection structure, thus avoiding mutual interference between the two optical paths, reducing the amount of interference signal received by the detector, and improving detection accuracy.

[0067] In addition, since no reflection structure is required, the laser beam and the echo signal can travel through the entire transmitting optical system 212 or receiving optical system 222 without turning back, which effectively reduces the total length and volume of the transmitting optical system 212 or receiving optical system 222.

[0068] like Figure 5 As shown, in an optional embodiment, the transceiver 200 further includes a lens barrel 240, within which the transmitting optical system 212, the receiving optical system 222, and the light-blocking plate 230 are all disposed. The lens barrel 240 allows the transmitting optical system 212, the receiving optical system 222, and the light-blocking plate 230 to be integrated into a single unit, facilitating their overall movement and assembly, and improving the assembly efficiency of the transceiver.

[0069] like Figure 4 As shown, in an optional embodiment, both the transmitting optical system 212 and the receiving optical system 222 have light-transmitting regions and light-blocking regions, with the light-blocking regions located at the edges of the optical systems. Specifically, the transmitting optical system 212 and the receiving optical system 222 are generally composed of multiple lenses arranged sequentially along the optical axis. All lenses located in the same optical system form a lens, which can be considered as a whole, and the aperture of this lens is generally larger than the aperture of the light propagating within it. Thus, when light propagates in the transmitting optical system 212 and the receiving optical system 222, only a portion of the optical system is used, generally the central region, which we call the light-transmitting region. The portion through which no light passes during use, generally the edge region, is called the light-blocking region. It should be noted that the ranges of the aforementioned light-transmitting and light-blocking regions are determined after the transmitting field of view of the transmitting module and the receiving field of view of the receiving module are determined.

[0070] At least a portion of the non-light-transmitting area of ​​at least one of the optical systems, the transmitting optical system 212 and the receiving optical system 222, is removed to form a planar structure on the outer wall of the optical system.

[0071] Since both the transmitting optical system 212 and the receiving optical system 222 have multiple lenses, the planar structure mentioned here can be formed by cutting off a portion of the edge region of at least one lens in the corresponding optical system, or by cutting off a portion of the edge region of all lenses in the corresponding optical system, depending on the range of the area and the aperture size of each lens.

[0072] To facilitate understanding, the above description will be explained using the example of forming a planar structure on the emitting optical system 212. If, according to the design, the width of the emitting optical system 212 after forming the planar structure needs to be x, and the diameter of all lenses within the emitting optical system 212 is greater than x, then at least a portion of the edge of each lens (generally the non-light-transmitting part) will be cut off to form one or more planes. All these planes are then combined to form the aforementioned planar structure. If only some lenses (which can be one, two, etc.) within the emitting optical system 212 have a diameter greater than x, and the diameter of other lenses is less than or equal to x, then only the edges of the lenses with a diameter greater than x need to be cut off to form the planar structure.

[0073] In this embodiment, the planar structure can be formed not only by cutting off the non-light-transmitting parts of the edges of the corresponding lenses in the transmitting optical system 212 and / or receiving optical system 222, but also by integrally molding it onto each lens. The specific choice can be made flexibly according to the manufacturing process and design requirements.

[0074] By adopting the structure provided in this embodiment, the volume of the transmitting optical system 212 and / or the receiving optical system 222 can be effectively reduced, the space occupied by the corresponding optical system and the overall size of the lidar can be reduced, and the lidar can be miniaturized.

[0075] The aforementioned planar structure can be formed in various ways, such as Figure 4 As shown, in an optional embodiment, the planar structure includes a first plane. The first plane is located between the optical axis of the transmitting optical system 212 and the optical axis of the receiving optical system 222, and the first plane forms a preset angle with the connecting line between the optical axes of the transmitting optical system 212 and the receiving optical system 222. This angle is not 0° and can be 90°, 10°, 45°, etc., depending on the design requirements. When the angle is 90°, the distance between the optical axis of the transmitting optical system 212 and the optical axis of the receiving optical system 222 is minimized.

[0076] Similarly, in this embodiment, the first plane can be formed not only by cutting off the non-light-transmitting portion of the edge of at least one lens in the transmitting optical system 212 and / or the receiving optical system 222 located near the other optical system, but also integrally formed on each lens. The specific choice can be flexibly made according to the manufacturing process and design requirements.

[0077] By adopting the structure provided in this embodiment, while effectively reducing the volume of the transmitting optical system 212 and / or the receiving optical system 222, the center distance between the optical axes of the transmitting module 210 and the receiving module 220 can also be reduced, thereby reducing the blind zone of the lidar.

[0078] like Figure 4 As shown, to further reduce the volume of the transmitting optical system 212 and / or the receiving optical system 222, in another optional embodiment, the planar structure includes not only the first plane described above, but also a second plane 260 corresponding to the first plane. The corresponding second plane 260 and the first plane are respectively disposed on both sides of the same optical system.

[0079] The positions of the first and second planes 260 mentioned above are generally determined according to the light-transmitting area of ​​the lens. That is, after a portion of both sides of the lens is removed, it does not affect its ability to receive and emit laser light or receive and emit echo light signals. Typically, the projected area of ​​the optical system with the first and second planes 260 on the plane where the laser source is located is generally slightly larger than the projected area of ​​the laser source. At the same time, the projected area of ​​the optical system on the plane where the laser source is located is also positively correlated with the entrance pupil diameter.

[0080] like Figure 4As shown, in a specific embodiment, both the transmitting optical system 212 and the receiving optical system 222 have a first plane and a second plane 260 formed therein, and both the first plane and the second plane 260 are perpendicular to the connecting line between the optical axes of the transmitting optical system 212 and the receiving optical system 222. This structure ensures a small distance between the optical axes of the transmitting optical system 212 and the receiving optical system 222, and also makes both the optical axes of the transmitting optical system 212 and the receiving optical system 222 smaller in size, thereby reducing the size of the transceiver device and facilitating the miniaturization design of the lidar.

[0081] Of course, in other embodiments, the planar structure can be configured in other ways, which is not the only one here.

[0082] In an optional embodiment, both the transmitting optical system 212 and the receiving optical system 222 employ the optical systems provided in the above embodiments, and the lens structures of the transmitting optical system 212 and the receiving optical system 222 are identical. This structure allows the transmitting optical system 212 and the receiving optical system 222 to be inspected using the same inspection device, which helps to improve the inspection rate.

[0083] To reduce the impact of ambient light and filter echo on the receiving optical systems provided in the above embodiments, such as Figure 5 As shown, in one optional embodiment, the receiving optical system 222 further includes a first aperture 270 located between the third lens 130 and the fourth lens 140. In another optional embodiment, the receiving optical system 222 further includes a second aperture 271 located between the fourth lens 140 and the image plane. In yet another optional embodiment, the receiving optical system 222 further includes a first aperture 270 located between the third lens 130 and the fourth lens 140, and a second aperture 271 located between the fourth lens 140 and the image plane.

[0084] like Figure 4 As shown, in an optional embodiment, the transceiver 200 further includes a filter 280 located between the receiving optical system 222 and the detector 221. The filter 280 can reduce the probability of stray light entering the detector 221, thereby improving detection accuracy.

[0085] Furthermore, since the receiving optical system 222 adopts the optical system 100 provided in the above embodiments, its chief ray angle (CRA) is small, which has little impact on the transmittance of the filter 280, ensuring that the filter 280 has high transmittance. At the same time, when considering the bandwidth of the filter 280, the influence of the incident angle does not need to be considered, reducing the bandwidth of the filter 280 and reducing the impact of stray light on the lidar.

[0086] The optical path principle of the receiving optical system 222 provided in this embodiment is as follows: Figure 6 As shown:

[0087] In the diagram, d represents the central field of view principal ray, c represents the 0.2 field of view principal ray, b represents the 0.6 field of view principal ray, and a represents the 1 field of view principal ray. All principal rays entering filter 280 are parallel to the optical axis and incident perpendicularly to filter 280, thus ensuring the high transmittance of filter 280. However, when the incident angle increases, the transmittance of filter 280 decreases, and the transmitted light band shifts towards shorter wavelengths.

[0088] Therefore, although the transceiver 200 provided in this embodiment is equipped with a filter 280, it has little impact on the transmittance of the echo light signal. That is, the transceiver 200 provided in this embodiment has both low transmittance of ambient light and high transmittance of echo light signal, which meets the usage requirements.

[0089] like Figure 4 As shown, in an optional embodiment, the laser source 211 and the detector are integrated on the same circuit board 290. Compared with the traditional lidar transceiver 200, the transceiver 200 provided in this embodiment adopts an integrated modular design, with the transmitting device (laser source 211) and the receiving device (detector) integrated on a single circuit board 290. This reduces the spacing between devices, enables dense arrangement of devices, and ensures high-resolution lidar detection.

[0090] In another embodiment of the present invention, a lidar is provided, including the transceiver provided in the above embodiments. In addition, the lidar generally includes a housing, within which the transceiver is mounted.

[0091] The lidar provided in this embodiment of the invention employs the transceiver devices provided in the above embodiments, which can effectively improve the field of view and detection accuracy.

[0092] The above description is merely a preferred embodiment of the present invention and only specifically describes the technical principles of the present invention. These descriptions are only for explaining the principles of the present invention and should not be construed as limiting the scope of protection of the present invention in any way. Based on this explanation, any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention, as well as other specific embodiments of the present invention that can be conceived by those skilled in the art without creative effort, should be included within the scope of protection of the present invention.

Claims

1. An optical system for use in lidar, characterized in that, The optical system includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially from the object plane to the image plane along the optical axis. The first lens has negative refractive power, while the second lens, the third lens, and the fourth lens all have positive refractive power. Wherein, the object-side surface of the first lens is concave and the image-side surface is convex; the object-side surface of the second lens is concave and the image-side surface is convex; the third lens is a biconvex lens; and the fourth lens is a plano-convex lens with a convex object-side surface and a planar image-side surface. The optical system has an optical path of 55-70mm, an effective focal length of 20-35mm, a field of view of 80-105°, and a back focal length of 0-4mm.

2. The optical system as described in claim 1, characterized in that, The diameters of the first lens, the second lens, the third lens, and the fourth lens increase sequentially.

3. The optical system as described in claim 1, characterized in that, The optical system satisfies the following relationship: 1.5 <n1<1.6;2.0<n2<2.1;1.5<n3<1.6;1.8<n4<1.9; Wherein, n1 is the refractive index of the first lens at a wavelength of 950nm, n2 is the refractive index of the second lens at a wavelength of 950nm, n3 is the refractive index of the third lens at a wavelength of 950nm, and n4 is the refractive index of the fourth lens at a wavelength of 950nm.

4. A transceiver device, characterized in that, The transceiver includes a transmitting module and a receiving module. The transmitting module includes a laser source and a transmitting optical system located on the light-emitting side of the laser source. The receiving module includes a detector and a receiving optical system located on the light-incident side of the detector. Wherein, at least one of the optical systems in the transmitting optical system and the receiving optical system is the optical system according to any one of claims 1-3.

5. The transceiver as described in claim 4, characterized in that, The transmitting module and the receiving module are arranged side by side with their optical axes parallel. The transceiver also includes a light-blocking plate located between the transmitting module and the receiving module. The light-blocking plate is used to separate the light transmitted by the transmitting module and the receiving module respectively.

6. The transceiver as described in claim 5, characterized in that, The transceiver also includes a lens barrel, and the transmitting optical system, the receiving optical system and the light-blocking plate are all disposed inside the lens barrel.

7. The transceiver as described in claim 4, characterized in that, Both the transmitting optical system and the receiving optical system have a light-transmitting area and a light-blocking area, wherein the light-blocking area is located at the edge of the optical system; At least a portion of the non-light-transmitting area of ​​at least one optical system in the transmitting optical system and the receiving optical system is removed to form a planar structure on the outer wall of the optical system.

8. The transceiver as described in claim 7, characterized in that, The planar structure includes a first plane, which is located between the optical axis of the transmitting optical system and the optical axis of the receiving optical system, and the first plane is set at a preset angle to the connecting line between the optical axis of the transmitting optical system and the optical axis of the receiving optical system.

9. The transceiver as described in claim 8, characterized in that, The planar structure also includes a second plane that corresponds one-to-one with the first plane, and the corresponding second plane and the first plane are respectively disposed on both sides of the same optical system.

10. The transceiver as described in claim 4, characterized in that, Both the transmitting optical system and the receiving optical system employ the aforementioned optical system, and the lens structures of the transmitting optical system and the receiving optical system are identical.

11. The transceiver as described in claim 10, characterized in that, The receiving optical system further includes a first aperture located between the third lens and the fourth lens; And / or, the receiving optical system further includes a second aperture located between the fourth lens and the image plane.

12. The transceiver as described in claim 11, characterized in that, The transceiver also includes a filter located between the receiving optical system and the detector.

13. The transceiver apparatus according to any one of claims 4-12, characterized in that, The laser source and the detector are integrated on the same circuit board.

14. A lidar, characterized in that, Includes the transceiver device according to any one of claims 4-13.

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