Laser radar equipment and vehicle

Abstract

The laser radar equipment provided by the invention can be applied to multiple scenes such as unmanned driving, artificial intelligence, 3D printing, AR, VR and MR, and has the excellent performance of being small in size, high in sensitivity, fast in response and capable of achieving long-distance detection. The laser radar device provided by the invention comprises a PCSEL, a beam splitting element, a scanning mirror and a receiver. Wherein the PCSEL is used for emitting a first light beam to the beam splitting element, then the beam splitting element transmits the first light beam to the scanning mirror, and the first light beam is scanned by the scanning mirror and emitted to an external target object. After receiving the first light beam, an external object reflects a second light beam, and the second light beam is reflected to the beam splitting element after being received by the scanning mirror and is reflected to the receiver through the beam splitting element again.

Description

Technical Field

[0001] The present application relates to the field of laser radar technology, and more specifically, to a laser radar device and a vehicle. Background Art

[0002] Laser radar equipment is a high-precision, high-resolution measuring device that uses laser beams to scan and measure targets. It can obtain information such as the target's distance, speed, and direction. It plays an important role in autonomous driving systems, robot navigation, security monitoring, and smart homes.

[0003] In the autonomous driving system, direct time of flight (dToF) radar equipment has many problems such as large size (usually located on the top of the vehicle), high assembly cost, expensive light source (such as equipment using fiber lasers) and low two-dimensional scanning frame rate, which cannot meet the performance requirements of vehicle-mounted LiDAR equipment. Therefore, how to achieve a smaller and better-performing vehicle-mounted LiDAR device is a problem that needs to be solved. Summary of the invention

[0004] The present application provides a laser radar device that can be used in vehicles and has the excellent performance of being small in size, high in sensitivity, fast in response and capable of achieving long-distance detection.

[0005] In the first aspect, the embodiment of the present application provides a laser radar device. The laser radar device includes: a photonic crystal surface emitting laser PCSEL, a beam splitter, a scanning mirror and a receiver, wherein the PCSEL is used to emit a first light beam to the beam splitter; the beam splitter is used to transmit the first light beam to the scanning mirror and reflect the second light beam from the scanning mirror to the receiver; the scanning mirror is used to reflect the first light beam to the target object and reflect the second light beam reflected from the target object to the beam splitter; the receiver is used to receive the second light beam from the beam splitter.

[0006] The laser radar device provided by the present application uses PCSEL as a laser source. When PCSEL is used as a laser source, the diffraction-limited light beam emitted (i.e., the divergence angle of the emitted light beam is small) enables the laser radar device provided by the present application to have a higher resolution. In addition, the laser device provided by the present application uses a scanning mirror to realize the scanning switching of the light beam, which can reduce the volume of the laser radar device while improving the response speed of the device. In addition, the scanning mirror can make the angle of the emitted laser smaller, so it can also reduce the receiving angle of the receiver, thereby realizing long-distance measurement.

[0007] In combination with the first aspect, in some implementations of the first aspect, the beam splitting element is a semi-transparent and semi-reflective mirror.

[0008] In combination with the first aspect, in certain implementations of the first aspect, the beam splitting element is a polarization beam splitter PBS, and the device also includes a 1 / 4 wave plate, which is located on the optical path between the beam splitting element and the scanning mirror, wherein the first light beam is linearly polarized light, and the 1 / 4 wave plate is used to change the polarization direction of the first light beam transmitted from the PBS and the polarization direction of the second light beam from the scanning mirror.

[0009] Since PCSEL can emit polarized light beams, the energy loss of light passing through PBS can be reduced by designing the beam splitter as PBS. At the same time, since the reflected light from external objects received by the system is also polarized, the polarization state of the reflected light from the object is converted by the λ / 4 wave plate, and then it can be reflected to the receiver through the PBS, and then received by the receiver, ensuring the performance of the system.

[0010] It is understandable that the polarized light output by the PCSEL depends on the 2D photonic crystal structure design of the PCSEL itself. In the present application, the polarized light output by the PCSEL can be P light or S light, which is not limited in the present application.

[0011] In combination with the first aspect, in certain implementations of the first aspect, the device also includes at least two reflecting elements, which are located on the optical path between the beam splitting element and the receiver, and the at least two reflecting elements are used to reflect the second light beam emitted from the beam splitting element to form a Z-shaped optical path between the beam splitting element and the receiver.

[0012] Based on the above solution, the design of the Z-shaped optical path can further reduce the receiving viewing angle of the receiver, thereby achieving ranging at a wider distance.

[0013] In combination with the first aspect, in certain implementations of the first aspect, the device also includes a beam expansion element, which is located on the optical path between the beam splitting element and the receiver, and the beam expansion element is used to reduce the diameter of the second light beam reflected by the beam splitting element.

[0014] Based on the above scheme, by reducing the diameter of the light beam received by the receiver through the beam expansion element, it is possible to ensure that the energy of the received light beam is more concentrated and reduce the noise of the receiver, thereby achieving the purpose of optimizing the performance of the lidar equipment.

[0015] In combination with the first aspect, in some implementations of the first aspect, a diameter of the scanning mirror is the same as a diameter of an emitting surface of the PCSEL.

[0016] It is understandable that when the diameter of the scanning mirror is smaller than the diameter of the PCSEL emitting surface, the light cannot be fully received by the scanning mirror, resulting in a reduction in the effective output power of the light, thereby shortening the ranging capability of the device. When the diameter of the scanning mirror is larger than the diameter of the PCSEL emitting surface, the scanning mirror will respond more slowly. Therefore, setting the diameter of the scanning mirror to be the same as the diameter of the PCSEL emitting surface can not only ensure the response speed of the scanning mirror and enable the system to have a higher switching response, but also ensure the power of the system and improve the signal-to-noise ratio of the system.

[0017] In combination with the first aspect, in some implementations of the first aspect, the scanning mirror is a micro-electromechanical system (MEMS) scanning mirror.

[0018] Compared with traditional scanning mirrors, MEMS scanning mirrors have the advantages of small size, low cost, high scanning frequency, fast response speed and low power consumption, which can significantly improve the performance of lidar equipment.

[0019] In combination with the first aspect, in some implementations of the first aspect, the receiver is a one-dimensional SiPM array.

[0020] The SiPM array can increase the pulse repetition rate of the laser radar device, thereby achieving the effect of improving the system response time or frame rate, so that the laser radar device provided in this application can meet the needs of high-quality vehicle applications.

[0021] In combination with the first aspect, in certain implementations of the first aspect, the direction of the one-dimensional SiPM array is perpendicular to the fast axis of the scanning mirror.

[0022] Based on the above solution, the system frame rate can be improved by aligning the direction of the one-dimensional SiPM array perpendicular to the fast axis of the scanning mirror.

[0023] In combination with the first aspect, in certain implementations of the first aspect, a viewing angle of the receiver is the same as a divergence angle of a beam emitted by the PCSEL.

[0024] It should be noted that when the viewing angle of the receiver is smaller than the beam divergence angle of the PCSEL, the receiving power of the receiver will be lost. However, the larger the viewing angle of the receiver, the greater the optical power of the signal that can be detected, but the noise level of the receiver will increase. Therefore, in the present application scheme, the viewing angle of the receiver is set to be equal to the beam divergence angle of the PCSEL, which can balance the detected optical power and the signal-to-noise ratio of the system, and ensure the optimal performance of the lidar equipment.

[0025] In combination with the first aspect, in certain implementations of the first aspect, the width of the laser radar device is less than or equal to 50 mm, the length of the laser radar device is less than or equal to 60 mm, and the height of the laser radar device is less than or equal to 22 mm.

[0026] In a second aspect, an embodiment of the present application provides a vehicle, which includes a vehicle body and the laser radar device described in the first aspect or any possible implementation thereof, wherein the laser radar device is disposed on the vehicle body.

[0027] In combination with the second aspect, in certain implementations of the second aspect, the vehicle further includes a rearview mirror, and the laser radar device is disposed in a space of the vehicle next to the rearview mirror.

[0028] In a third aspect, an embodiment of the present application provides a vehicle-mounted system, which includes the laser radar device described in the first aspect or any possible implementation thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the working principle of the laser radar system applicable to the embodiment of the present application.

[0030] Figure 2 A schematic structural diagram of the first laser radar device 200 provided in an embodiment of the present application.

[0031] Figure 3 A schematic diagram of the corresponding relationship between the divergence angle of the laser beam emitted by the PCSEL provided in an embodiment of the present application and the diameter of the PCSEL emission surface.

[0032] Figure 4 Schematic diagram of a one-dimensional SiPM array receiving pulses when a two-dimensional scanning mirror provided in an embodiment of the present application is rotated to different angles.

[0033] Figure 5 A schematic diagram comparing the beam diameters of the laser radar device 200 provided in an embodiment of the present application and a mechanical laser radar device.

[0034] Figure 6 A top view and a front view of the laser radar device 200 provided in an embodiment of the present application.

[0035] Figure 7 A schematic structural diagram of a second laser radar device 700 provided in an embodiment of the present application.

[0036] Figure 8 A schematic structural diagram of a third laser radar device 800 provided in an embodiment of the present application.

[0037] Fig. 9 A schematic structural diagram of the fourth laser radar device 900 provided in an embodiment of the present application.

[0038] Fig.10 A schematic structural diagram of the fifth laser radar device 1000 provided in an embodiment of the present application.

[0039] Fig.11 A schematic diagram of a usage scenario of a vehicle 1100 provided in an embodiment of the present application. DETAILED DESCRIPTION

[0040] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0041] In order to facilitate understanding of the embodiments of the present application, the following explanation is made.

[0042] First, the terms "first", "second", etc. and various numbers in the text descriptions or drawings of the embodiments of the present application shown below are only used for the convenience of description, and are not necessarily used to describe a specific order or sequence, and are not used to limit the scope of the embodiments of the present application. For example, to distinguish different light beams, etc.

[0043] Second, the terms "including" and "having" and any variations thereof in the embodiments of the present application shown below are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or apparatuses.

[0044] Third, in the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions, and the embodiments or designs described as "exemplary" or "for example" should not be interpreted as being more preferred or more advantageous than other embodiments or designs. The use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way for easy understanding.

[0045] Fourth, in the drawings of this application, for the convenience of explanation, the drawings are only examples and are not drawn strictly according to scale.

[0046] For ease of understanding, the technical terms involved in this application are first briefly explained and illustrated.

[0047] 1. Lidar is a radar system that emits laser beams to detect the position, speed and other characteristic quantities of a target. Figure 1As shown in the figure, its working principle is to calculate the relative distance to the target object by emitting and receiving laser beams, analyzing the return time after the laser encounters the target object, that is, half of the round-trip time (elapsed time, Et), and using the three-dimensional coordinates, reflectivity, texture and other information of a large number of dense points on the surface of the target object collected in this process to quickly obtain the three-dimensional model of the measured target and various related data such as lines, surfaces, and bodies, establish a three-dimensional point cloud (point cloud) map, and draw an environmental map to achieve the purpose of environmental perception. Since the speed of light is very fast and the flight time may be very short, the measurement equipment is required to have very high accuracy. In terms of effect, the more dimensions (beams) of the laser radar, the higher the measurement accuracy and the higher the safety.

[0048] 2. Field of view (FOV), also known as azimuth, includes horizontal field of view and vertical field of view, which refers to the detection angle of the lidar device in the horizontal and vertical directions.

[0049] 3. Photonic crystal surface emitting laser (PCSEL), also known as photonic crystal laser, has attracted much attention due to its excellent laser properties. The main feature of this laser is that it has both high-power output and high-quality beams, and provides functions that are not easy to achieve with other types of lasers, such as polarization and beam mode control, as well as on-chip beam direction control, thereby eliminating the need for bulky external optical devices. For LiDAR devices based on PCSEL, the divergence angle is smaller, the beam diameter is smaller, and the collimation is higher than that of LiDAR devices with general laser light sources, so that it also has the characteristics of small divergence angle and small beam diameter at a distance away from the PCSEL laser. Therefore, when PCSEL is used in a LiDAR system, it does not require an external lens system and its related complex adjustment process, which can reduce the cost, weight and size of the LiDAR system.

[0050] 4. Silicon photo multiplier (SiPM), composed of multiple single photon avalanche diodes (SPAD) with quenching resistors, also known as superpixels or microcells. SiPM is a compact solid-state optical sensing device with high gain and the ability to detect light down to the photon level, generating an output current pulse after absorbing a photon. It is suitable for sensing, quantifying and timing all light levels down to a single photon.

[0051] 5. The micro electro mechanical system (MEMS) scanning mirror is a miniaturized optical device. Its principle is to use micro electro mechanical system technology to manufacture tiny movable mirrors, and to scan and position the light beam by controlling the movement of the mirrors. The MEMS scanning mirror consists of two parts: a tiny mirror and a control drive system. The mirror has a high reflectivity and a small inertial mass. The control drive system includes a micro motor and a control circuit for the movement of the aerial mirror. The micro motor usually uses electromagnetic drive or piezoelectric drive to generate torque by applying an electric field or current to cause the mirror to rotate or tilt slightly. The working principle of the MEMS scanning mirror is based on the reflection and interference of light. When the incident light beam hits the mirror, the light beam will be reflected according to the law of reflection. By controlling the rotation or tilt of the mirror, the direction of the reflected light beam can be changed. When the mirror rotates or tilts at a certain frequency, the scanning of the light beam can be achieved.

[0052] 6. Polarization beam splitter (PBS), a prism formed by gluing the bottom edges of two 45-degree isosceles right-angle prisms. When nonlinear polarized light is incident on PBS, PBS will reflect the S polarized light (perpendicular to the plane of the incident light) and allow the P polarized light (parallel to the plane of the incident light) to pass. Alternatively, when nonlinear polarized light is incident on PBS, PBS will reflect the P polarized light and allow the S polarized light to pass.

[0053] The system provided in this application can be applied to all optical fields that require laser radar equipment, such as unmanned driving, artificial intelligence, 3D printing, augmented reality (AR), virtual reality (VR), and mixed reality (MR).

[0054] As a key component of autonomous driving, LiDAR can provide timely feedback on complex road conditions, and the car's central processor can then make the right decision and drive along the right route, thereby avoiding various vehicles and pedestrians and ensuring driving safety. Compared with high-resolution cameras, LiDAR can not only accurately identify objects at a distance, but also accurately detect objects during the day with strong sunlight, at night with dark light, and even in rainy and foggy weather with low visibility, to ensure driving safety. Therefore, LiDAR equipment has become an indispensable sensing device for autonomous driving.

[0055] At present, the size of vehicle-mounted laser radar equipment is generally large. For example, in a disclosed mechanical laser radar equipment scheme (patent US7969558B2), the lasers of 64 end-emitting lasers are converted into parallel light by using 8 giant lenses. However, the 64 end emitters in this scheme must adjust the optical axis one by one according to the photodetector during manufacturing, which is not only complicated to assemble, but also leads to expensive assembly costs. At the same time, since the laser beam is scanned by a mechanical rotating mirror, even if a complex lens system is used to reshape the beam, the laser radar device still has a large distorted light spot, resulting in overlapping beam points during beam scanning, reducing the spatial resolution of the system, and long-term use will also cause large motor losses. In addition, the light intensity width of the end-emitting laser used in this scheme is 20μm, the beam divergence angle is 50°, and when a lens with a focal length of 5.4mm is used, the angular resolution of the laser radar is 0.21°. If the angular resolution is to be increased to 0.05°, a lens with a focal length of 23mm is required. At this time, the diameter of the laser beam emitted by the laser radar device is 21mm, which makes the volume of the laser radar device under the 64-beam laser structure very large and can only be installed on the top of the car. In order to reduce the volume of the laser radar device, in another solution (patent US9874635B1), a fiber laser with a wavelength of 1.55μm is used as the light source. Although compared with the first solution, this solution can reduce the volume of the laser radar device to a certain extent, because the light source includes many components such as pump lasers, wavelength division multiplexers (WDM), gain fibers, isolators and collimators, the ability to reduce the volume of the laser radar device is very limited, and this solution also has the disadvantage of expensive laser light sources. In addition, there are also laser radar devices that use PCSEL two-dimensional arrays as light sources. However, since the diameter of each PCSEL light-emitting surface is very small, the diffusion angle of the light beam is very small. Therefore, when used as the light source of the laser radar device, the measurement distance is short and objects at a distant position cannot be measured, which cannot meet the use requirements of vehicle-mounted laser radar equipment. In addition, the viewing angle of the receiver used in the device cannot be adjusted, so when the light source's emission angle is reduced due to the control of the current, the receiver may not be able to receive.

[0056] Based on the above problems, the present application proposes a laser radar device with a small size and high sensitivity. While achieving longer distance ranging, it can also improve the response time or frame rate of the laser radar device, which can greatly meet the needs of vehicle-mounted applications.

[0057] Figure 2 This is a schematic structural diagram of the first laser radar device 200 provided in the embodiment of the present application. Figure 2As shown, the laser radar device 200 includes a PCSEL 210, a half mirror 220, a scanning mirror 230, and a receiver 240. Among them, the PCSEL 210 is used to generate a first light beam and emit the first light beam to the half mirror 220. The half mirror 220 is used to transmit the first light beam from the PCSEL 210 to the scanning mirror 230, and reflect the second light beam from the scanning mirror 230 to the receiver 240. The scanning mirror 230 is used to reflect the first light beam from the half mirror 220 to the target object, and reflect the second light beam reflected from the target object to the half mirror 220. The receiver 240 is used to receive the second light beam reflected from the half mirror 220.

[0058] Specifically, when the laser radar device 200 starts working, the PCSEL 210 generates a first light beam and emits the first light beam to the semi-transparent and semi-reflective mirror 220. The semi-transparent and semi-reflective mirror 220 transmits the first light beam to the scanning mirror 230, and the scanning mirror 230 reflects the first light beam out of the laser radar device 200. Subsequently, after the first light beam emitted from the laser radar device 200 encounters an external object, it reflects a second light beam to the laser radar device 200. The second light beam is received by the scanning mirror 230 and reflected by the scanning mirror 230 to the semi-transparent and semi-reflective mirror 220. The semi-transparent and semi-reflective mirror 220 reflects the second light beam from the scanning mirror 230 to the receiver 240 to be received. At this time, the laser radar device 200 can calculate the distance to the target object based on the time from the PCSEL 210 emitting the first light beam to the receiver 240 receiving the second light beam.

[0059] Optionally, the scanning mirror 230 is a micro-electro-mechanical system (MEMS) two-dimensional scanning mirror. Compared with traditional scanning mirrors, MEMS scanning mirrors have the advantages of small size, fast response speed and low power consumption, thereby achieving the purpose of reducing the size of the laser radar equipment, improving the response speed of the laser radar equipment and reducing the power consumption of the equipment.

[0060] It should be noted that when the scanning mirror 230 is a MEMS two-dimensional scanning mirror, the present application does not limit the driving mode of the MEMS, and any one of the four driving modes of electrostatic drive, electromagnetic drive, piezoelectric drive and electrothermal drive can be selected according to the application scenario and application requirements of the laser radar device 200.

[0061] For PCSEL, the laser beam it emits is almost a collimated beam, that is, the laser beam has the same beam diameter anywhere in the laser radar system. At the same time, the divergence angle of the laser beam emitted by PCSEL is inversely proportional to the diameter of the PCSEL emitting surface, such as Figure 3 As shown, where λ is the wavelength of the laser beam, ω 0is the divergence angle of the laser beam. Figure 3 It can be seen that if the wavelength λ of the laser beam emitted by PCSEL 210 is 940nm and the diameter φ of the PCSEL emission surface is 0.5mm, the divergence angle of the laser beam emitted by the PCSEL is 0.2°. When the diameter φ of the PCSEL emission surface is 2mm, the divergence angle of the laser beam emitted by the PCSEL is 0.05°. Generally speaking, when the divergence angle of the laser beam is 0.05°, the resolution of the laser radar device is sufficient. Therefore, a PCSEL with an emission surface diameter φ of 2mm can be selected as the laser light source of the laser radar device 200, that is, the diameter φ of the emission surface of PCSEL 210 is 2mm.

[0062] It should be noted that the diameter φ of the emitting surface of the laser light source PCSEL 210 also determines the diameter of the scanning mirror 230. If the diameter of the scanning mirror 230 is smaller than the diameter of the emitting surface of the PCSEL 210, the light emitted by the PCSEL 210 will be shielded at the scanning mirror 230, thereby reducing the effective output power of the laser radar device and shortening the ranging capability. On the contrary, if the diameter of the scanning mirror 230 is larger than the diameter of the emitting surface of the PCSEL 210, although the sensitivity is improved, the response speed of the larger-sized reflector is slower, and some noise will be introduced, reducing the signal-to-noise ratio. Therefore, in order to improve the sensitivity and response speed of the laser radar device while taking into account the output power of the device, in some embodiments, the diameter of the scanning mirror 230 is set to be the same as the diameter φ of the emitting surface of the PCSEL 210, or the diameter of the scanning mirror 230 is set to be within a preset range with the difference between the diameter φ of the emitting surface of the PCSEL 210, thereby ensuring the optimal performance of the laser radar device 200.

[0063] In some embodiments, the viewing angle ω of the receiver 240 can be set to be the same as the divergence angle of the laser beam emitted by the laser light source PCSEL 210, wherein in the embodiment of the present application, the viewing angle ω of the receiver is defined as the angle at which the receiver can receive light. The viewing angle of the receiver 240 is set to the divergence angle of the laser beam emitted by the laser light source PCSEL 210 because, when the viewing angle of the receiver 240 is less than the divergence angle of the beam emitted by the PCSEL 210, the optical power received by the receiver 240 will be insufficient, resulting in insufficient output power of the laser radar device 200. However, when the viewing angle of the receiver 240 is greater than the divergence angle of the beam emitted by the PCSEL 210, as the viewing angle of the receiver 240 increases, although the detected optical power increases, the signal intensity is saturated, and as the viewing angle increases, the noise level of the receiver 240 will also increase at the same time, resulting in a decrease in the signal-to-noise ratio of the laser radar device 200. Therefore, in a preferred case, the viewing angle of the receiver 240 can be set equal to the beam divergence angle of the PCSEL 210, or the viewing angle of the receiver 240 can be set to be approximately equal to the beam divergence angle of the PCSEL 210, for example, the difference between the viewing angle of the receiver 240 and the beam divergence angle of the PCSEL 210 can be within an acceptable range. For example, when a PCSEL 210 with a diameter φ of 2 mm of the emitting surface is used as a light source, the divergence angle of the laser beam emitted by the PCSEL 210 is 0.05°, and at this time, the viewing angle of the receiver 240 can be set to 0.05° or approximately equal to 0.05°.

[0064] In order to improve the pulse repetition rate of the laser radar device 200, the receiver 240 is optionally a one-dimensional SiPM array, such as Figure 4 Alternatively, the receiver 240 is a high-gain receiver or a receiver array that is equivalent to a one-dimensional SiPM array.

[0065] It should be noted that if the second light beam (also referred to as the second laser beam or the second laser pulse) received by the laser radar device 200 is reflected from a target object 300m away, according to Figure 1It can be obtained that at this time, the round-trip time of the laser pulse (i.e., the first light beam, also referred to as the first laser beam) emitted by the laser radar device 200 is 2μs. Therefore, in order to avoid pulse collisions, the minimum period of the laser pulse emitted by the laser radar device 200 is 2μs. Generally speaking, in the application of the vehicle field, in order to avoid traffic accidents, the duration of the frame per second needs to be greater than 10fps. Therefore, when the laser radar device 200 is applied to a car, the total pulse emitted in one frame of the laser radar device is 0.1s / 2μs=50000, for example, it can be a combination of 200 pulses in the vertical direction and 250 pulses in the horizontal direction. At this time, combined with the divergence angle of the laser beam emitted by the PCSEL, the size of the field of view Fovh in the horizontal direction is Fovh=250pixel×0.05°=12.5°, which is far from enough for the laser radar device. Therefore, in the present application scheme, a one-dimensional SiPM array can be used to expand the field of view. For example, assuming that the period of the first light beam emitted by the laser radar device 200 is 0.4 μs, then 5 pulses reflected from the object can be received within 2 μs, but these 5 pulses may collide. In this case, the two-dimensional scanning mirror can be combined with the two-dimensional scanning mirror at different rotation angles (such as Figure 4 (a) in the figure corresponds to different SiPM elements, so that the two-dimensional scanning mirror at different rotation angles reflects the second light beams at different distances returned from the object to different SiPMs for reception, thereby expanding the field of view of the structured light radar device 200 while achieving measurement.

[0066] In order to detect the timing of individual pulses respectively through the SiPM array, in some embodiments, the direction of the one-dimensional SiPM array can be set to be perpendicular to the fast axis of the scanning mirror 230.

[0067] Figure 5 A schematic diagram comparing the beam diameters of the laser radar device and the mechanical laser radar device provided in this application. Figure 5 As shown in the figure, for the same resolution of 0.05°, the laser beam diameter of the mechanical laser radar device in the prior art is 21mm or larger, which results in the size of the rotating mechanical structure of the laser radar device driven by the motor being very large, so that the laser radar device cannot be installed in the space next to the rearview mirror inside the car and can only be installed on the roof. However, in the present application, the width of the laser radar device is less than or equal to 50mm, the length is less than or equal to 60mm, and the height is less than or equal to 22mm (such as Figure 6 As shown, Figure 6 (a) is a top view of the laser radar device provided in this application, Figure 6(b) is the main view of the laser radar device provided by the present application), which can be easily installed in the space next to the rearview mirror inside the car, and can provide a scanning range with a field of view of 24° in the vertical direction and 40° in the horizontal direction. At the same time, in the laser radar device of the present application, the diameter of the laser beam at the two-dimensional scanning mirror is only 2mm, and the noise caused by sunlight is also reduced, so that the solution of the present application can obtain a distance range of 200m with a laser power of less than 20dB.

[0068] In order to reduce the energy loss of the light beam, increase the optical power received by the receiver, and improve the signal-to-noise ratio, Figure 7 A schematic structural diagram of a second laser radar device 700 according to an embodiment of the present application is provided. Figure 7 As shown, the laser radar device 700 includes a PCSEL 210, a semi-transparent and semi-reflective mirror 220, a scanning mirror 230, a third reflective element 710, a lens 720 and a receiver 240. Figure 2 Unlike the laser radar device shown in the figure, the laser radar device 700 also includes a third reflective element 710 and a lens 720. The third reflective element 710 is located on the optical path between the semi-transparent and semi-reflective mirror 220 and the receiver 240, and is used to reflect the second light beam from the semi-transparent and semi-reflective mirror 220 to the lens 720. The lens 720 is used to shape the second light beam (for example, to collimate the second light beam, etc.) to gather the energy of the second light beam. In addition, the functions and possible implementation methods of the PCSEL 210, the semi-transparent and semi-reflective mirror 220, the scanning mirror 230 and the receiver 240 can refer to the above Figure 2 The relevant instructions in will not be repeated here.

[0069] Specifically, when the laser radar device 700 starts working, the PCSEL 210 generates a first light beam and emits the first light beam to the semi-transparent and semi-reflective mirror 220. The semi-transparent and semi-reflective mirror 220 transmits the first light beam to the scanning mirror 230, and the scanning mirror 230 reflects the first light beam out of the laser radar device 700. Subsequently, after the first light beam emitted from the laser radar device 700 encounters an external object, it reflects a second light beam to the laser radar device 700. The second light beam is received by the scanning mirror 230 and reflected by the scanning mirror 230 to the semi-transparent and semi-reflective mirror 220. The semi-transparent and semi-reflective mirror 220 reflects the second light beam from the scanning mirror 230 to the third reflective element 710. The third reflective element 710 continues to reflect the second light beam to the lens 720, and the lens 720 transmits the second light beam to the receiver 240 to be received. Similarly, the laser radar device 700 can calculate the distance to the target object based on the time from the PCSEL 210 emitting the first light beam to the receiver 240 receiving the second light beam.

[0070] Optionally, in order to further reduce the energy loss of the system, in some other embodiments, a beam expansion element may be used instead of the lens 720 (eg Fig.10 The beam expansion element 1010 shown in the figure can reduce the diameter of the light beam from the semi-transparent and semi-reflective mirror 220 through the beam expansion element, which can also increase the received light power of the receiver and improve the signal-to-noise ratio of the laser radar device.

[0071] In order to reduce the viewing angle of the receiver, reduce the noise received by the receiver, and improve the signal-to-noise ratio, Figure 8 A schematic structural diagram of a third laser radar device 800 of an embodiment of the present application is provided. Figure 8 As shown, the laser radar device 800 includes a PCSEL 210, a semi-transparent and semi-reflective mirror 220, a scanning mirror 230, a first reflective element 810, a second reflective element 820 and a receiver 240. Figure 2 The laser radar device 800 is different from the laser radar device shown in the figure in that the laser radar device 800 further includes a first reflecting element 810 and a second reflecting element 820, and the first reflecting element 810 and the second reflecting element 820 are located on the optical path between the semi-transparent and semi-reflective mirror 220 and the receiver 240, so that a Z-shaped optical path is formed between the semi-transparent and semi-reflective mirror 220 and the receiver 240. The functions and possible implementation methods of the PCSEL 210, the semi-transparent and semi-reflective mirror 220, the scanning mirror 230 and the receiver 240 can refer to the above Figure 2 The relevant instructions in will not be repeated here.

[0072] Specifically, when the laser radar device 800 starts working, the PCSEL 210 generates a first light beam and emits the first light beam to the semi-transparent and semi-reflective mirror 220. The semi-transparent and semi-reflective mirror 220 transmits the first light beam to the scanning mirror 230, and the scanning mirror 230 reflects the first light beam out of the laser radar device 800. Subsequently, after the first light beam emitted from the laser radar device 800 encounters an external object, it reflects a second light beam to the laser radar device 800, and the second light beam is received by the scanning mirror 230 and reflected by the scanning mirror 230 to the semi-transparent and semi-reflective mirror 220. The semi-transparent and semi-reflective mirror 220 reflects the second light beam from the scanning mirror 230 to the first reflecting element 810, and at the same time, the first reflecting element 810 continues to reflect the second light beam to the second reflecting element 820, and the second reflecting element 820 continues to reflect the second light beam to the first reflecting element 810, and the second light beam is reflected by the first reflecting element again and received by the receiver 240. Similarly, the laser radar device 800 can calculate the distance to the target object based on the time from when the PCSEL 210 emits the first light beam to when the receiver 240 receives the second light beam.

[0073] Optionally, the first reflective element 810 and the second reflective element 820 are reflectors, or other reflective elements, etc., which are not limited in this application. Optionally, in order to improve the reflection efficiency of the reflective element, in some embodiments, the first reflective element 810 and the second reflective element 820 may also be coated with an anti-reflection film, etc.

[0074] It should be noted that the laser radar device 800 is described by taking the example of a device containing two reflective elements. The laser radar device 800 can be provided with multiple reflective elements according to the application scenario and application requirements, and this application does not limit this.

[0075] Since the first light beam emitted by the PCSEL is a polarized light beam, in order to reduce energy loss, Figure 2 The semi-transparent and semi-reflective mirror 230 in the embodiment is replaced by a PBS and a 1 / 4 wave plate. Specifically, Fig. 9 The schematic structure diagram of the fourth laser radar device 900 of the embodiment of the present application is provided. Among them, the laser radar device 900 includes a PCSEL 210, a PBS 910, a 1 / 4 wave plate 920, a scanning mirror 230, a third reflecting element 710, a lens 720 and a receiver 240. Specifically, the PBS 910 is used to transmit the first light beam to the 1 / 4 wave plate 920, and reflect the polarized light beam from the 1 / 4 wave plate 920 to the third reflecting element 710. The 1 / 4 wave plate is located on the optical path between the PBS 910 and the scanning mirror 230, and is used to change the polarization direction of the first light beam transmitted from the PBS 910, and change the polarization direction of the second light beam from the scanning mirror 230. The third reflecting element 710 is used to reflect the polarized light beam from the 1 / 4 wave plate 920 to the lens 720. The functions and possible implementation methods of the PCSEL 210, the semi-transparent and semi-reflective mirror 220, the scanning mirror 230 and the receiver 240 can refer to the above Figure 2 For the relevant description in the above, the functions and possible implementation methods of the third reflective element 710 and the lens 720 can refer to the above Figure 7 The relevant instructions in will not be repeated here.

[0076] Specifically, when the laser radar device 900 starts working, if the first light beam generated by the PCSEL 210 is P light, the PCSEL 210 emits the P light to the PBS 910, and the PBS 910 transmits the P light to the 1 / 4 wave plate 920, and the 1 / 4 wave plate 920 changes the polarization direction of the P light to generate elliptically polarized light, for example Fig. 9The right-handed elliptically polarized light shown in the figure is emitted to the scanning mirror 230, and the scanning mirror 230 reflects the elliptically polarized light out of the laser radar device 900. Subsequently, after the right-handed elliptically polarized light emitted from the laser radar device 900 encounters an external object, it reflects a second light beam with a polarization direction of left-handed elliptically polarized light to the laser radar device 900, and the left-handed elliptically polarized light is received by the scanning mirror 230, and is reflected by the scanning mirror 230 to the 1 / 4 wave plate 920, and the 1 / 4 wave plate 920 processes the left-handed elliptically polarized light to generate S light, and emits the S light to the PBS 910, and then the PBS 910 reflects the S light to the third reflecting element 710, and after being reflected by the third reflecting element 710, it is emitted to the lens 720, and is transmitted by the lens 720 to the receiver 240 to be received. Similarly, the laser radar device 900 can calculate the distance to the target object according to the time from the PCSEL 210 emitting the first light beam to the receiver 240 receiving the second light beam.

[0077] Alternatively, in the present application, the quarter wave plate can be made by fine processing of a uniaxial birefringent crystal (e.g., quartz) or a biaxial crystal (e.g., mica) that is easy to peel with a certain thickness. In some embodiments, the quarter wave plate 920 can also be attached to the surface of the PBS 910 using optical adhesive.

[0078] Optionally, the 1 / 4 wave plate 920 is a thin film 1 / 4 wave plate, which may be a polymer organic thin film 1 / 4 wave plate, such as a polyester film, a polypropylene film, etc., which is not limited in the present application.

[0079] It should be noted that Fig. 9 The laser radar device 900 shown is explained by taking the PCSEL 210 generating P light as an example. In some embodiments, the PCSEL 210 can also output S light, depending on the needs of the photonic crystal design and application scenarios.

[0080] exist Fig. 9 Based on the fourth laser radar device 900 shown, Fig.10 Schematic diagram of the structure of the fifth laser radar device 1000 of the embodiment of the present application. The laser radar device 1000 includes a PCSEL 210, a PBS 910, a quarter wave plate 920, a scanning mirror 230, a beam expansion element 1010, a first reflecting element 810, a second reflecting element 820 and a receiver 240. Specifically, the beam expansion element 1010 is located on the optical path between the PBS 910 and the first reflecting element 810, and is used to reduce the diameter of the second light beam from the PBS 910. It can be understood that the functions and possible implementation methods of the PCSEL 210, the scanning mirror 230 and the receiver 240 can refer to the above Figure 2For the relevant description in the above, the functions and possible implementation methods of the first reflective element 810 and the second reflective element 820 can refer to the above Figure 8 The relevant instructions in will not be repeated here.

[0081] Specifically, still taking the first light beam generated by PCSEL 210 as P light as an example, when laser radar device 1000 starts working, PCSEL 210 emits P light to PBS 910, PBS 910 transmits P light to 1 / 4 wave plate 920, 1 / 4 wave plate 920 changes the polarization direction of P light to generate elliptically polarized light, and emits elliptically polarized light to scanning mirror 230, scanning mirror 230 reflects elliptically polarized light out of laser radar device 1000. Subsequently, after the elliptically polarized light emitted from laser radar device 1000 encounters an external object, the external object reflects the elliptically polarized light with the changed polarization direction to laser radar device 1000, and is reflected to 1 / 4 wave plate 920 by scanning mirror 230, and then, S light is generated through 1 / 4 wave plate 920 and emitted to PBS 910. The PBS 910 emits the S light to the beam expansion element 1010. The S light is beam-contracted by the beam expansion element 1010 and then emitted to the first reflection element 810. After multiple reflections by the first reflection element 810 and the second reflection element 820, the S light is received by the receiver 240. Similarly, the laser radar device 1000 can calculate the distance to the target object based on the time from the PCSEL 210 emitting the first light beam to the receiver 240 receiving the second light beam.

[0082] It should be noted that for the above Figure 2 , Figures 7 to 10 The embodiments may be implemented independently or in combination with each other. For example, Figure 8 The laser radar device 800 shown can also be used with Figure 7 The laser radar device 700 shown is used in combination with Figure 8 The laser radar device 800 shown has a lens 720 added thereto. Alternatively, Figure 8 The embodiment shown can also be used with Fig.10 The embodiments shown are combined with each other, for example Figure 8 A beam expansion element 1010 is added to the laser radar device 800 to further improve the performance of the device.

[0083] In addition, the present application also provides a means of transportation, such as Fig.11 The automobile 1100 shown, Fig.11 As shown, the car 1100 includes a vehicle body 1110 and various laser radar devices provided in the embodiments of the present application, such as the above-mentioned Figure 2 , Figures 7 to 10The laser radar device 200, laser radar device 700, laser radar device 800, laser radar device 900 and laser radar device 1000 shown in the figure and other embodiments not shown in the figure within the protection scope of the present application. Among them, the laser radar device provided in the embodiment of the present application is installed on the vehicle body 1110, for example, it can be installed at the rearview mirror of the vehicle.

[0084] It should be noted that the means of transportation provided by the present application are not limited to the above-mentioned automobiles. The means of transportation provided by the present application can be cars, trucks, motorcycles, buses, ships, airplanes, helicopters, lawn mowers, recreational vehicles, amusement park vehicles, construction equipment, trams, golf carts, trains, and carts, etc., and the embodiments of the present application do not make special limitations.

[0085] In addition, the embodiment of the present application also provides a vehicle-mounted system, which includes various laser radar devices provided in the embodiment of the present application, such as the above-mentioned Figure 2 , Figures 7 to 10 The laser radar device 200, the laser radar device 700, the laser radar device 800, the laser radar device 900 and the laser radar device 1000 shown, as well as other not shown embodiments, are within the scope of protection of the present application.

[0086] An embodiment of the present application also provides a controller, which includes an input / output interface, a processor and a memory, wherein the processor is used to control the input / output interface to send and receive signals or information, the memory is used to store a computer program, and the processor is used to call and run the computer program from the memory, so that the controller performs operations such as calculating the round-trip time of a laser radar device, thereby calculating the distance between the target object and the laser radar device.

[0087] An embodiment of the present application further provides a chip, which includes a processor and a data interface. The processor reads instructions stored in a memory through the data interface to execute the method executed by the above-mentioned controller.

[0088] Optionally, as an implementation manner, the chip may further include a memory, in which instructions are stored, and the processor is used to execute the instructions stored in the memory. When the instructions are executed, the processor is used to execute the above method.

[0089] It will be understood that, unless otherwise defined, technical or scientific terms used herein shall have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs.

[0090] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A laser radar device, characterized in that: include: Photonic crystal surface emitting laser PCSEL, beam splitter, scanning mirror and receiver, The PCSEL is used to emit a first light beam toward the beam splitting element; The beam splitting element is used to transmit the first light beam to the scanning mirror and reflect the second light beam from the scanning mirror to the receiver; The scanning mirror is used to reflect the first light beam to a target object, and reflect the second light beam reflected from the target object to the beam splitting element; The receiver is used to receive the second light beam from the beam splitting element.

2. The laser radar device according to claim 1, characterized in that: The beam splitting element is a semi-transparent and semi-reflective mirror.

3. The laser radar device according to claim 1, characterized in that: The beam splitting element is a polarized beam splitter PBS, and the device further comprises a quarter wave plate, which is located on the optical path between the beam splitting element and the scanning mirror, wherein the first light beam is linearly polarized light, The 1 / 4 wave plate is used to change the polarization direction of the first light beam transmitted from the PBS and the polarization direction of the second light beam from the scanning mirror.

4. The laser radar device according to any one of claims 1 to 3, characterized in that: The device further comprises at least two reflective elements, wherein the at least two reflective elements are located on an optical path between the beam splitting element and the receiver. The at least two reflecting elements are used to reflect the second light beam emitted from the beam splitting element, so that a Z-shaped light path is formed between the beam splitting element and the receiver.

5. The laser radar device according to any one of claims 1 to 4, characterized in that: The device further comprises a beam expansion element, the beam expansion element being located in the optical path between the beam splitting element and the receiver, The beam expansion element is used to reduce the diameter of the second light beam reflected by the beam splitting element.

6. The laser radar device according to any one of claims 1 to 5, characterized in that: The diameter of the scanning mirror is the same as the diameter of the emitting surface of the PCSEL.

7. The laser radar device according to any one of claims 1 to 6, characterized in that: The scanning mirror is a micro-electromechanical system (MEMS) scanning mirror.

8. The laser radar device according to any one of claims 1 to 7, characterized in that: The receiver is a one-dimensional SiPM array.

9. The laser radar device according to claim 8, characterized in that: The one-dimensional SiPM array is oriented perpendicular to the fast axis of the scanning mirror.

10. The laser radar device according to any one of claims 1 to 9, characterized in that: The viewing angle of the receiver is the same as the divergence angle of the beam transmitted by the PCSEL.

11. The laser radar device according to any one of claims 1 to 10, characterized in that: The width of the laser radar device is less than or equal to 50 mm, the length of the laser radar device is less than or equal to 60 mm, and the height of the laser radar device is less than or equal to 22 mm.

12. A means of transport, characterized in that: It comprises a vehicle body and a laser radar device as described in any one of claims 1 to 11, wherein the laser radar device is arranged on the vehicle body.

13. The vehicle according to claim 12, characterized in that: The vehicle also includes a rearview mirror, and the laser radar device is arranged in a space of the vehicle next to the rearview mirror.

14. A vehicle-mounted system, characterized in that: Comprising a laser radar device as described in any one of claims 1 to 11.

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