Membrane electromagnetic mirror

Abstract

An electromagnetic movable scanner device (900) for performing an optical scan is provided for use in an optical ranging and detection (LiDAR) system. The apparatus (900) includes a stage (920) including a film substrate. The platform (920) is pivotable about an axis. The apparatus (900) also includes a reflector (950) disposed on the platform (920), a plurality of magnets (941-946) disposed proximate to and separate from one or more edges of the film substrate, and one or more electrical windings (930) mounted on the platform (920). At least a portion of the electrical winding (930) is disposed below the reflector (950). When the one or more electrical windings (930) carry an electrical current, interaction between magnetic fields formed by the plurality of magnets (941-946) and the electrical windings (930) is operable to electromagnetically move the reflector (950) to scan a field of view in at least one direction.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Patent Application Serial No. 18 / 237,359, filed on August 23, 2023, entitled “Film Electromagnetic Mirror” and U.S. Provisional Patent Application Serial No. 63 / 401,988, filed on August 29, 2022, entitled “Film Electromagnetic Mirror”. The contents of both applications are hereby incorporated by reference in their entirety for all purposes. Technical Field

[0003] The present disclosure relates generally to optical scanning, and more particularly to an electromagnetic movable scanner device for performing optical scanning for use in a light ranging and detection (LiDAR) system. Background Art

[0004] Light detection and ranging (LiDAR) systems use light pulses to create images or point clouds of the external environment. LiDAR systems can be scanning or non-scanning systems. Some typical scanning LiDAR systems include a light source, a light emitter, a light steering system, and a light detector. The light source generates a light beam, which is guided in a specific direction by the light steering system when emitted from the LiDAR system. When the emitted light beam is scattered or reflected by an object, a portion of the scattered light or reflected light returns to the LiDAR system to form a return light pulse. The light detector detects the return light pulse. Using the difference between the time when the return light pulse is detected and the time when the corresponding light pulse in the light beam is emitted, the LiDAR system can determine the distance to the object based on the speed of light. This technique for determining distance is called time of flight (ToF) technology. The light steering system can guide the light beam along different paths to allow the LiDAR system to scan the surrounding environment and generate an image or point cloud. A typical non-scanning LiDAR system illuminates the entire field of view (FOV) instead of scanning the entire FOV. An example of a non-scanning LiDAR system is a flash LiDAR, which can also use ToF technology to measure the distance to an object. LiDAR systems can also use techniques other than time-of-flight and scanning to measure their surroundings. Summary of the invention

[0005] Microelectromechanical system (MEMS) mirrors have been used in LiDAR systems to steer laser beams. There are different kinds of MEMS mirrors. Electromagnetic MEMS mirrors use the Lorentz force generated by current in a magnetic field to control the movement of the mirror. Electrostatic MEMS mirrors use electrostatic forces to control the movement of the mirror. There are also piezoelectric MEMS mirrors and various other kinds of MEMS mirrors.

[0006] In traditional MEMS mirrors, silicon wafers are typically used as substrates. However, there are two significant problems with this approach. The first problem relates to the reliability of silicon-based MEMS mirrors. As a solid material, silicon wafers are fragile. Long-term rotation and vibration of the silicon substrate, especially at high intensity and high frequency, may cause fatigue and eventually damage the mirror. The second problem is related to the size limitations of silicon-based MEMS mirrors. These mirrors are typically designed to be smaller in size because larger rotating mirrors become more susceptible to damage due to reliability issues. In addition, cost considerations exacerbate size limitations. Due to the high cost characteristics of silicon wafers, manufacturing silicon-based MEMS mirrors on silicon wafers requires high yields. Therefore, silicon-based MEMS chips are typically designed to be smaller in size to achieve higher yields. For example, a typical silicon-based MEMS mirror has a diameter of no more than 7 mm.

[0007] However, in LiDAR systems, larger scanning mirrors are often preferred. One reason for this preference is that larger scanning mirrors provide larger optical apertures and improved light guiding and collection capabilities. With larger scanning mirrors, LiDAR systems can have extended scanning distances, and LiDAR receivers can detect weaker light signals from farther distances.

[0008] The above two issues have caused a contradiction regarding the use of MEMS mirrors in LiDAR systems. From the perspective of cost and reliability, it is advantageous to maintain a smaller size of MEMS mirrors. However, from the perspective of LiDAR functionality, a larger MEMS mirror is beneficial to enhance the scanning capability of the system. To resolve this contradiction, one solution may be to employ a reinforced MEMS mirror substrate that can achieve functions and features comparable to those of silicon-based MEMS mirrors.

[0009] Embodiments of the present invention disclose a novel membrane electromagnetic mirror solution. In one example, the mirror does not use a silicon-based substrate, but a metal-based substrate. This solution allows the size of the mirror to be scaled up to one inch or even larger, providing substantial advantages over the limitations of smaller silicon-based MEMS mirrors. It should be noted that while the present disclosure focuses on electromagnetic MEMS mirrors, the solution can be extended to other types of MEMS mirrors.

[0010] In one embodiment, an electromagnetically movable scanner device for performing optical scanning used in a LiDAR system is provided. The device includes a platform, which includes a film substrate. The platform can pivot around an axis. The device also includes a reflector disposed on the platform, a plurality of magnets disposed near and separated from one or more edges of the film substrate, and one or more electrical windings mounted on the platform. At least a portion of the electrical winding is disposed below the reflector. When the one or more electrical windings carry current, the interaction between the magnetic field formed by the plurality of magnets and the electrical winding can operate to electromagnetically move the reflector, thereby scanning a field of view along at least one direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present application may be best understood by referring to the embodiments described below in conjunction with the accompanying drawings, in which like components may be represented by like reference numerals.

[0012] Figure 1 One or more exemplary LiDAR systems disposed or included in a motor vehicle are illustrated.

[0013] Figure 2 is a block diagram illustrating the interaction between an exemplary LiDAR system and a number of other systems including a vehicle perception and planning system.

[0014] Figure 3 is a block diagram illustrating an exemplary LiDAR system.

[0015] Figure 4 is a block diagram illustrating an exemplary fiber-based laser source.

[0016] FIG. 5A to FIG. 5C An exemplary LiDAR system that uses pulse signals to measure the distance to objects disposed in a field of view (FOV) is illustrated.

[0017] Figure 6 is a block diagram illustrating an exemplary apparatus for implementing the systems, apparatus, and methods in various embodiments.

[0018] Figure 7 The diagram shows the Lorentz force on a current-carrying conductor in a magnetic field.

[0019] Fig. 8A An exemplary MEMS mirror device is illustrated according to one embodiment.

[0020] Figure 8B An exemplary two-dimensional MEMS mirror device is illustrated according to one embodiment.

[0021] Fig.9AIllustrated is a top view of an exemplary MEMS mirror device according to one embodiment.

[0022] Fig. 9B Illustrated is a cross-sectional view of an exemplary MEMS mirror device according to one embodiment.

[0023] Fig. 10A is a block diagram illustrating an exemplary arrangement of components in a steering mechanism of a LiDAR system according to one embodiment.

[0024] Fig. 10B is a block diagram illustrating an exemplary arrangement of components in another steering mechanism of a LiDAR system according to one embodiment. DETAILED DESCRIPTION

[0025] In order to provide a more thorough understanding of various embodiments of the present invention, the following description sets forth many specific details, such as specific configurations, parameters, examples, etc. However, it should be appreciated that this description is not intended to limit the scope of the present invention, but is intended to provide a better description of exemplary embodiments.

[0026] Throughout the specification and claims, unless the context clearly dictates otherwise, the following terms have the meanings explicitly associated herein:

[0027] As used herein, the phrase "in one embodiment" does not necessarily refer to the same embodiment, even though it may. Thus, as described below, the various embodiments of the present disclosure can be easily combined without departing from the scope or spirit of the invention.

[0028] As used herein, the term "or" is an inclusive "or" operator and is equivalent to the term "and / or" unless the context clearly dictates otherwise.

[0029] Unless the context clearly dictates otherwise, the term "based on" is not exclusive and allows for being based on additional factors not described.

[0030] As used herein, and unless the context dictates otherwise, the term "coupled to . . .

[0031] "Coupled to" is intended to include both direct coupling (where two elements coupled to each other are in contact with each other) and indirect coupling (where at least one additional element is located between the two elements). Therefore, the terms "coupled to..." and "coupled with..." are used synonymously. In the context of a networked environment where two or more components or devices are able to exchange data, the terms "coupled to..." and "coupled with..." are also used to mean "communicatively coupled with...", possibly via one or more intermediate devices. The components or devices can be optical, mechanical and / or electrical devices.

[0032] Although the following description uses the terms "first", "second", etc. to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the various described examples, a first sensor may be referred to as a second sensor, and similarly, a second sensor may be referred to as a first sensor. The first sensor and the second sensor may both be sensors, and in some cases, may be separate and different sensors.

[0033] In addition, throughout the specification, the meanings of “a,” “an,” and “the” include plural forms, and the meaning of “in” may include “in” and “on.”

[0034] Although some of the various embodiments provided herein constitute a single combination of inventive elements, it should be understood that the inventive subject matter is considered to include all possible combinations of disclosed elements. Thus, if one embodiment includes elements A, B, and C, and another embodiment includes elements B and D, the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if this paper does not explicitly discuss. In addition, the transition term "comprising" means having parts or components, or those parts or components. As used herein, the transition term "comprising" is inclusive or open-ended, and does not exclude additional, unlisted elements or method steps.

[0035] As used in the description herein and throughout the claims that follow, when a system, engine, server, device, module, or other computing element is described as being configured to perform or execute functions on data in a memory, the meaning of "configured to" or "programmed to" is defined as one or more processors or cores of the computing element being programmed by a set of software instructions stored in the memory of the computing element to perform the set of functions on target data or data objects stored in the memory.

[0036] It should be noted that any language for computers should be understood to include any suitable combination of computing devices or network platforms (including servers, interfaces, systems, databases, agents, peers, engines, controllers, modules, or other types of computing devices operating alone or together). It should be understood that the computing device includes a processor configured to execute software instructions stored on a tangible, non-transitory computer-readable storage medium (e.g., a hard drive, FPGA, PLA, solid-state drive, RAM, flash memory, ROM, or any other volatile or non-volatile storage device). The software instructions configure or program the computing device to provide roles, responsibilities, or other functions, as discussed below with respect to the disclosed apparatus. In addition, the disclosed technology can be embodied as a computer program product, which includes a non-transitory computer-readable medium storing software instructions that cause the processor to perform the disclosed steps associated with the implementation of a computer-based algorithm, process, method, or other instructions. In some embodiments, various servers, systems, databases or interfaces exchange data using standardized protocols or algorithms, which may be based on HTTP, HTTPS, AES, public-private key exchange, web service API, known financial transaction protocols or other electronic information exchange methods. Data exchange between devices can be carried out through the following: packet switching networks, the Internet, LAN, WAN, VPN or other types of packet switching networks; circuit switching networks; cell switching networks; or other types of networks.

[0037] MEMS mirrors are used for scanning in LiDAR systems. However, traditional silicon-based MEMS substrates present challenges related to reliability and size limitations. The pursuit of larger MEMS mirrors has been hampered by cost and reliability considerations. To address these issues, a novel membrane electromagnetic mirror is proposed that provides high mechanical strength and enables larger mirror sizes and extended scanning distances. This makes the MEMS mirror more robust, durable, and cost-effective, which will enhance LiDAR performance.

[0038] Embodiments of the present invention are described below. In various embodiments of the present invention, an electromagnetically movable scanner device for performing optical scanning used in a LiDAR system is provided. The device includes a platform, which includes a film substrate. The platform can pivot around an axis. The device also includes a reflector disposed on the platform, a plurality of magnets disposed near one or more edges of the film substrate and separated from the one or more edges, and one or more electrical windings mounted on the platform. At least a portion of the electrical winding is disposed under the reflector. When the one or more electrical windings carry current, the interaction between the magnetic field formed by the plurality of magnets and the electrical winding can operate to electromagnetically move the reflector, thereby scanning the field of view along at least one direction.

[0039] Figure 1 One or more exemplary LiDAR systems 110 are illustrated as being arranged or included in a motor vehicle 100. The vehicle 100 may be a car, a sport utility vehicle (SUV), a truck, a train, a van, a bicycle, a motorcycle, a tricycle, a bus, a motor scooter, a tram, a ship, a boat, an underwater vehicle, an airplane, a helicopter, an unmanned aerial vehicle (UAV), a spacecraft, and the like. The motor vehicle 100 may be a vehicle having any level of automation. For example, the motor vehicle 100 may be a partially automated vehicle, a highly automated vehicle, a fully automated vehicle, or an unmanned vehicle. A partially automated vehicle may perform some driving functions without human driver intervention. For example, a partially automated vehicle may perform blind spot monitoring, lane keeping and / or lane change operations, automatic emergency braking, smart cruise control, and / or traffic following, and the like. Certain operations of a partially automated vehicle may be limited to specific applications or driving scenarios (e.g., limited to highway driving). A highly automated vehicle may generally perform all operations of a partially automated vehicle, but with fewer restrictions. Highly automated vehicles can also detect their own limits when operating the vehicle and request the driver to take over control of the vehicle when necessary. Fully automated vehicles can perform all vehicle operations without driver intervention, but can also detect their own limits and request the driver to take over when necessary. Driverless vehicles can operate autonomously without any driver intervention.

[0040] In a typical configuration, the motor vehicle 100 includes one or more LiDAR systems 110 and 120A-120I. Each of the LiDAR systems 110 and 120A-120I can be a scanning-based LiDAR system and / or a non-scanning LiDAR system (e.g., flash LiDAR). A scanning-based LiDAR system scans one or more light beams in one or more directions (e.g., horizontal and vertical directions) to detect objects in a field of view (FOV). A non-scanning-based LiDAR system emits a laser to illuminate the FOV without scanning. For example, a flash LiDAR is a type of non-scanning-based LiDAR system. A flash LiDAR can emit a laser to illuminate the FOV simultaneously using a single light pulse or light beams.

[0041] LiDAR systems are common sensors used in at least partially automated vehicles. Figure 1As shown, the motor vehicle 100 may include a single LiDAR system 110 (e.g., without LiDAR systems 120A-120I) disposed at the highest position of the vehicle (e.g., on top of the vehicle). Placing the LiDAR system 110 on top of the vehicle facilitates 360-degree scanning around the vehicle 100. In some other embodiments, the motor vehicle 100 may include multiple LiDAR systems, including two or more of the systems 110 and / or 120A-120I. Figure 1 As shown, in one embodiment, multiple LiDAR systems 110 and / or 120A-120I are attached to the vehicle 100 at different locations of the vehicle. For example, LiDAR system 120A is attached to the vehicle 100 at the right front corner; LiDAR system 120B is attached to the vehicle 100 at the front center location; LiDAR system 120C is attached to the vehicle 100 at the left front corner; LiDAR system 120D is attached to the vehicle 100 at the right side mirror; LiDAR system 120E is attached to the vehicle 100 at the left side mirror; LiDAR system 120F is attached to the vehicle 100 at the rear center location; LiDAR system 120G is attached to the vehicle 100 at the right rear corner; LiDAR system 120H is attached to the vehicle 100 at the left rear corner; and / or LiDAR system 120I is attached to the vehicle 100 at the center toward the rear end (e.g., the rear end of the top of the vehicle). It should be understood that one or more LiDAR systems may be distributed and attached to a vehicle in any desired manner, and Figure 1 Only one embodiment is illustrated. As another example, LiDAR systems 120D and 120E can be attached to the B-pillars of vehicle 100 instead of rearview mirrors. As another example, LiDAR system 120B can be attached to the windshield of vehicle 100 instead of the front bumper.

[0042] In some embodiments, LiDAR systems 110 and 120A-120I are independent LiDAR systems with their respective laser sources, control electronics, transmitters, receivers and / or steering mechanisms. In other embodiments, some of LiDAR systems 110 and 120A-120I can share one or more components to form a distributed sensor system. In one example, optical fiber is used to deliver lasers from a centralized laser source to all LiDAR systems. For example, system 110 (or another system positioned in the center or any position of vehicle 100) includes a light source, a transmitter and a light detector, but no steering mechanism. System 110 can distribute transmitted light to each of systems 120A-120I. Transmitted light can be distributed via optical fiber. Optical connectors can be used to couple optical fibers to each of systems 110 and 120A-120I. In some examples, one or more systems in systems 120A-120I include a steering mechanism, but no light source, transmitter or light detector. The steering mechanism may include one or more movable mirrors, such as one or more polygonal mirrors, one or more single plane mirrors, one or more multi-plane mirrors, etc. The embodiments of the light source, the transmitter, the steering mechanism and the light detector will be described in more detail below. Via the steering mechanism, one or more systems in the system 120A-120I scan the light into one or more corresponding FOVs and receive the corresponding return light. The return light is formed by scattering or reflecting the transmitted light by one or more objects in the FOV. The system 120A-120I may also include a collecting lens and / or other optical devices to focus and / or guide the return light into an optical fiber, and the optical fiber delivers the received return light to the system 110. The system 110 includes one or more light detectors for detecting the received return light. In some examples, the system 110 is arranged inside the vehicle so that it is in a temperature-controlled environment, and one or more systems 120A-120I may be at least partially exposed to the external environment.

[0043] Figure 2 2 is a block diagram 200 illustrating the interaction between an onboard LiDAR system 210 and a plurality of other systems including a vehicle perception and planning system 220. The LiDAR system 210 may be mounted on or integrated into a vehicle. The LiDAR system 210 includes a sensor that scans laser light into the surrounding environment to measure the distance, angle, and / or velocity of objects. Based on the scattered light returned to the LiDAR system 210, it may generate sensor data (e.g., image data or 3D point cloud data) representing the perceived external environment.

[0044] The LiDAR system 210 may include one or more of a short-range LiDAR sensor, a mid-range LiDAR sensor, and a long-range LiDAR sensor. The short-range LiDAR sensor measures objects up to about 20-50 meters from the LiDAR sensor. The short-range LiDAR sensor can be used, for example, to monitor nearby moving objects (e.g., pedestrians crossing the road in a school zone), parking assistance applications, etc. The medium-range LiDAR sensor measures objects up to about 70-200 meters from the LiDAR sensor. The medium-range LiDAR sensor can be used, for example, to monitor road intersections, assist in merging into or exiting a highway, etc. The long-range LiDAR sensor can measure objects located 200 meters and above. Long-range LiDAR sensors are typically used when the vehicle is traveling at high speeds (e.g., on a highway), so that the vehicle's control system may only have a few seconds (e.g., 6-8 seconds) to respond to any situation detected by the LiDAR sensor. Figure 2 As shown, in one embodiment, LiDAR sensor data can be provided to vehicle perception and planning system 220 via communication path 213 for further processing and control of vehicle operation. Communication path 213 can be any wired or wireless communication link capable of transmitting data.

[0045] Still reference Figure 2 In some embodiments, other onboard sensors 230 are configured to provide additional sensor data alone or in conjunction with the LiDAR system 210. Other onboard sensors 230 may include, for example, one or more cameras 232, one or more radars 234, one or more ultrasonic sensors 236, and / or other sensors 238. Camera 232 may capture images and / or videos of the external environment of the vehicle. Camera 232 may capture, for example, high-definition (HD) video with millions of pixels per frame. The camera includes an image sensor that facilitates the generation of monochrome or color images and videos. Color information may be important when interpreting data in certain situations (e.g., interpreting images of traffic lights). Color information may not be available from other sensors (such as LiDAR or radar sensors). Camera 232 may include one or more of a narrow focal length camera, a wide focal length camera, a side camera, an infrared camera, a fisheye camera, and the like. The image and / or video data generated by camera 232 may also be provided to the vehicle perception and planning system 220 via a communication path 233 for further processing and control of vehicle operation. Communication path 233 may be any wired or wireless communication link capable of transmitting data. The camera 232 may be mounted or integrated into the vehicle at any location (eg, rearview mirror, pillar, front grille and / or rear bumper, etc.).

[0046] Other on-board sensors 230 may also include radar sensors 234. Radar sensors 234 use radio waves to determine the distance, angle, and speed of an object. Radar sensors 234 generate electromagnetic waves in the radio or microwave spectrum. Electromagnetic waves are reflected by objects, and some of the reflected waves return to the radar sensor, thereby providing information about the position and speed of the object. Radar sensors 234 may include one or more of short-range radars, medium-range radars, and long-range radars. Short-range radars measure objects about 0.1-30 meters from the radar. Short-range radars are useful in detecting objects near vehicles (such as other vehicles, buildings, walls, pedestrians, cyclists, etc.). Short-range radars can be used to detect blind spots, assist in lane changes, provide rear-end collision alerts, assist in parking, provide emergency braking, etc. Medium-range radars measure objects about 30-80 meters from the radar. Long-range radars measure objects located at about 80-200 meters. Medium-range and / or long-range radars can be used, for example, for traffic tracking, adaptive cruise control, and / or highway automatic braking. Sensor data generated by radar sensor 234 may also be provided to vehicle perception and planning system 220 via communication path 233 for further processing and control of vehicle operation. Radar sensor 234 may be mounted or integrated into the vehicle at any location (e.g., rearview mirror, pillar, front grille and / or rear bumper, etc.).

[0047] Other on-board sensors 230 may also include ultrasonic sensors 236. Ultrasonic sensors 236 use sound waves or pulses to measure objects located outside the vehicle. The sound waves generated by ultrasonic sensors 236 are emitted to the surrounding environment. At least some of the emitted waves are reflected by the object and returned to the ultrasonic sensor 236. Based on the return signal, the distance of the object can be calculated. Ultrasonic sensors 236 can be used, for example, to check blind spots, identify parking spaces, provide lane change assistance in traffic, etc. The sensor data generated by ultrasonic sensors 236 can also be provided to the vehicle perception and planning system 220 via the communication path 233 for further processing and control of vehicle operation. Ultrasonic sensors 236 can be installed or integrated into the vehicle at any location (e.g., rearview mirrors, pillars, front grilles and / or rear bumpers, etc.).

[0048] In some embodiments, one or more other sensors 238 may be attached to the vehicle and may also generate sensor data. Other sensors 238 may include, for example, a global positioning system (GPS), an inertial measurement unit (IMU), etc. The sensor data generated by other sensors 238 may also be provided to the vehicle perception and planning system 220 via the communication path 233 for further processing and control of vehicle operation. It should be understood that the communication path 233 may include one or more communication links to transmit data between various sensors 230 and the vehicle perception and planning system 220.

[0049] In some embodiments, such as Figure 2 As shown, sensor data from other onboard sensors 230 can be provided to the onboard LiDAR system 210 via communication path 231. The LiDAR system 210 can process the sensor data from the other onboard sensors 230. For example, sensor data from a camera 232, a radar sensor 234, an ultrasonic sensor 236, and / or other sensors 238 can be correlated or fused with the sensor data LiDAR system 210, thereby at least partially offloading the sensor fusion process performed by the vehicle perception and planning system 220. It should be understood that other configurations can also be implemented to transmit and process sensor data from various sensors (e.g., data can be transmitted to a cloud or edge computing service provider for processing, and then the processing results can be transmitted back to the vehicle perception and planning system 220 and / or the LiDAR system 210).

[0050] Still reference Figure 2 In some embodiments, sensors on other vehicles 250 are used to provide additional sensor data alone or in conjunction with the LiDAR system 210. For example, two or more nearby vehicles may have their own LiDAR sensors, cameras, radar sensors, ultrasonic sensors, etc. Nearby vehicles can communicate and share sensor data with each other. Communication between vehicles is also known as V2V (vehicle-to-vehicle) communication. For example, Figure 2 As shown, sensor data generated by other vehicles 250 can be transmitted to vehicle perception and planning system 220 and / or onboard LiDAR system 210 via communication path 253 and / or communication path 251, respectively. Communication paths 253 and 251 can be any wired or wireless communication links capable of transmitting data.

[0051] Sharing sensor data facilitates better perception of the environment outside the vehicle. For example, the first vehicle may not sense a pedestrian that is behind the second vehicle but is approaching the first vehicle. The second vehicle can share sensor data related to the pedestrian with the first vehicle, so that the first vehicle can have additional reaction time to avoid colliding with the pedestrian. In some embodiments, similar to the data generated by sensor 230, the data generated by sensors on other vehicles 250 can be correlated or fused with sensor data generated by LiDAR system 210 (or other LiDAR systems located in other vehicles), thereby at least partially offloading the sensor fusion process performed by the vehicle perception and planning system 220.

[0052] In some embodiments, the smart infrastructure system 240 is used to provide sensor data alone or in conjunction with the LiDAR system 210. Certain infrastructures may be configured to communicate with vehicles to transfer information, and vice versa. Communication between vehicles and infrastructure is generally referred to as V2I (vehicle to infrastructure) communication. For example, the smart infrastructure system 240 may include a smart traffic light that can communicate its status to approaching vehicles with messages such as "turn yellow in 5 seconds". The smart infrastructure system 240 may also include its own LiDAR system installed near the intersection so that it can transmit traffic monitoring information to the vehicle. For example, a vehicle turning left at an intersection may not have sufficient sensing capabilities because some of its own sensors may be blocked by traffic in the opposite direction. In this case, the sensors of the smart infrastructure system 240 can provide useful data to the vehicle turning left. Such data may include, for example, traffic conditions, object information in the direction of vehicle turning, traffic light status and predictions, etc. These sensor data generated by the smart infrastructure system 240 can be provided to the vehicle perception and planning system 220 and / or the onboard LiDAR system 210 via communication paths 243 and / or 241, respectively. Communication paths 243 and / or 241 may include any wired or wireless communication links capable of transmitting data. For example, sensor data from the smart infrastructure system 240 can be transmitted to the LiDAR system 210 and correlated or fused with sensor data generated by the LiDAR system 210, thereby at least partially offloading the sensor fusion process performed by the vehicle perception and planning system 220. The above-mentioned V2V and V2I communications are examples of vehicle-to-X (V2X) communications, where "X" represents any other device, system, sensor, infrastructure, etc. that can share data with the vehicle.

[0053] Still reference Figure 2, via various communication paths, the vehicle perception and planning system 220 receives sensor data from one or more of the LiDAR system 210, other vehicle onboard sensors 230, other vehicles 250, and / or the smart infrastructure system 240. In some embodiments, different types of sensor data are related and / or fused by the sensor fusion subsystem 222. For example, the sensor fusion subsystem 222 can generate a 360-degree model using multiple images or videos captured by multiple cameras set at different locations of the vehicle. The sensor fusion subsystem 222 obtains sensor data from different types of sensors and uses the combined data to more accurately perceive the environment. For example, the onboard camera 232 may not capture a clear image because it is directly facing the sun or a light source (e.g., the headlights of another vehicle at night). The LiDAR system 210 may not be affected too much, and therefore the sensor fusion subsystem 222 can combine the sensor data provided by the camera 232 and the LiDAR system 210, and use the sensor data provided by the LiDAR system 210 to compensate for the unclear image captured by the camera 232. As another example, in rainy or foggy weather, radar sensor 234 may work better than camera 232 or LiDAR system 210. Accordingly, sensor fusion subsystem 222 may use sensor data provided by radar sensor 234 to compensate for sensor data provided by camera 232 or LiDAR system 210.

[0054] In other examples, sensor data generated by other onboard sensors 230 may have a lower resolution (e.g., radar sensor data) and, therefore, may need to be correlated and confirmed by the LiDAR system 210, which typically has a higher resolution. For example, the radar sensor 234 may detect a manhole cover (also known as a manhole cover) as an object that the vehicle is approaching. Due to the low resolution nature of the radar sensor 234, the vehicle perception and planning system 220 may not be able to determine whether the object is an obstacle that the vehicle needs to avoid. Therefore, the high resolution sensor data generated by the LiDAR system 210 can be used to correlate and confirm that the object is a manhole cover and will not cause damage to the vehicle.

[0055] The vehicle perception and planning system 220 further includes an object classifier 223. Using the raw sensor data and / or the associated / fused data provided by the sensor fusion subsystem 222, the object classifier 223 can use any computer vision technology to detect and classify objects and estimate the location of the objects. In some embodiments, the object classifier 223 can use machine learning-based techniques to detect and classify objects. Examples of machine learning-based techniques include using algorithms such as region-based convolutional neural networks (R-CNN), fast R-CNN, faster R-CNN, histogram of oriented gradients (HOG), region-based fully convolutional networks (R-FCN), single shot detectors (SSD), spatial pyramid pooling (SPP-net) and / or "You Only Look Once" (Yolo).

[0056] The vehicle perception and planning system 220 further includes a road detection subsystem 224. The road detection subsystem 224 locates the road and identifies objects and / or markings on the road. For example, based on the raw or fused sensor data provided by the radar sensor 234, the camera 232, and / or the LiDAR system 210, the road detection subsystem 224 can build a 3D model of the road based on machine learning techniques (e.g., a pattern recognition algorithm for identifying lanes). Using the 3D model of the road, the road detection subsystem 224 can identify objects (e.g., obstacles or debris on the road) and / or markings (e.g., lane lines, turn signs, crosswalk signs, etc.) on the road.

[0057] The vehicle perception and planning system 220 further includes a positioning and vehicle attitude subsystem 225. Based on the original or fused sensor data, the positioning and vehicle attitude subsystem 225 can determine the position of the vehicle and the attitude of the vehicle. For example, using sensor data from the LiDAR system 210, the camera 232 and / or GPS data, the positioning and vehicle attitude subsystem 225 can determine the precise position of the vehicle on the road and the six degrees of freedom of the vehicle (e.g., whether the vehicle is moving forward or backward, up or down, left or right). In some embodiments, a high-definition (HD) map is used for vehicle positioning. The HD map can provide a very detailed three-dimensional computer map to accurately locate the position of the vehicle. For example, using the HD map, the positioning and vehicle attitude subsystem 225 can accurately determine the current position of the vehicle (e.g., which lane of the road the vehicle is currently in, how close it is to the roadside or sidewalk) and predict the future position of the vehicle.

[0058] The vehicle perception and planning system 220 further includes an obstacle predictor 226. The objects identified by the object classifier 223 can be stationary (e.g., light poles, road signs) or dynamic (e.g., moving pedestrians, bicycles, another car). For moving objects, predicting their moving paths or future positions is important for avoiding collisions. The obstacle predictor 226 can predict obstacle trajectories and / or warn the driver or the vehicle planning subsystem 228 of potential collisions. For example, if the probability of the obstacle's trajectory intersecting the current moving path of the vehicle is high, the obstacle predictor 226 can generate such a warning. The obstacle predictor 226 can use various techniques to make such predictions. Such techniques include, for example, constant speed or acceleration models, constant rotation rate and speed / acceleration models, models based on Kalman filters and extended Kalman filters, models based on recursive neural networks (RNNs), models based on long short-term memory (LSTM) neural networks, encoder-decoder RNN models, etc.

[0059] Still reference Figure 2 In some embodiments, the vehicle perception and planning system 220 further includes a vehicle planning subsystem 228. The vehicle planning subsystem 228 may include one or more planners, such as a route planner, a driving behavior planner, and a motion planner. The route planner may plan the route of the vehicle based on the vehicle's current position data, target position data, traffic information, etc. The driving behavior planner uses the obstacle prediction results provided by the obstacle predictor 226 to adjust the timing and planned movements based on how other objects may move. The motion planner determines the specific operations that the vehicle needs to follow. The planning results are then transmitted to the vehicle control system 280 via the vehicle interface 270. Communication can be performed through communication paths 223 and 271, which include any wired or wireless communication links that can transmit data.

[0060] The vehicle control system 280 controls the vehicle's steering mechanism, throttle, brakes, etc. to operate the vehicle according to the planned route and movement. In some examples, the vehicle perception and planning system 220 may further include a user interface 260 that provides the user (e.g., the driver) with access to the vehicle control system 280, for example, to override or take over control of the vehicle when necessary. The user interface 260 may also be separate from the vehicle perception and planning system 220. The user interface 260 may communicate with the vehicle perception and planning system 220, for example to obtain and display raw or fused sensor data, identified targets, the position / attitude of the vehicle, etc. These displayed data can help the user better operate the vehicle. The user interface 260 may communicate with the vehicle perception and planning system 220 and / or the vehicle control system 280 via communication paths 221 and 261, respectively, and such communication paths include any wired or wireless communication links that can transmit data. It should be understood that Figure 2 The various systems, sensors, communication links and interfaces in the can be configured in any desired manner and are not limited to Figure 2 Configuration shown.

[0061] Figure 3 is a block diagram illustrating an exemplary LiDAR system 300. The LiDAR system 300 may be used to implement Figure 1 and Figure 2 The LiDAR systems 110, 120A-120I and / or 2101 and Figure 2. In one embodiment, the LiDAR system 300 includes a light source 310, a transmitter 320, an optical receiver and light detector 330, a steering system 340, and a control circuit system 350. These components are coupled together using communication paths 312, 314, 322, 332, 342, 352, and 362. These communication paths include communication links (wired or wireless, bidirectional or unidirectional) between various LiDAR system components, but do not have to be physical components themselves. Although the communication path can be implemented by one or more wires, buses, or optical fibers, the communication path can also be a wireless channel or a free space optical path, so that there is no physical communication medium. For example, in one embodiment of the LiDAR system 300, the communication path 314 between the light source 310 and the transmitter 320 can be implemented using one or more optical fibers. Communication paths 332 and 352 can represent optical paths implemented using free space optical components and / or optical fibers. And the communication paths 312, 322, 342 and 362 can be implemented using one or more wires carrying electrical signals. The communication paths can also include one or more of the above-mentioned types of communication media (for example, they can include optical fibers and free space optical components, or include one or more optical fibers and one or more wires).

[0062] In some embodiments, LiDAR system 300 may be a coherent LiDAR system. Frequency modulated continuous wave (FMCW) LiDAR is one example. Coherent LiDAR detects objects by mixing the return light from the object with the light from a coherent laser emitter. Thus, Figure 3 As shown, if the LiDAR system 300 is a coherent LiDAR, it can include a route 372 that provides a portion of the transmitted light from the transmitter 320 to the optical receiver and light detector 330. The transmitted light provided by the transmitter 320 can be modulated light and can be divided into two parts. One part is emitted to the FOV, and the second part is sent to the optical receiver and light detector of the LiDAR system. The second part is also referred to as the light kept local (LO) to the LiDAR system. The transmitted light is scattered or reflected by various objects in the FOV, and at least a portion of it forms return light. The return light is then detected and recombined by interference with the second part of the transmitted light that remains local. Coherent LiDAR provides a mechanism for optically sensing the range of objects and their relative speed along the line of sight (LOS).

[0063] The LiDAR system 300 may also include Figure 3Other components not shown in the diagram may include a power bus, power supplies, LED indicators, switches, etc. Additionally, there may be other communication connections between components, such as a direct connection between the light source 310 and the optical receiver and light detector 330 to provide a reference signal so that the time from the emission of a light pulse to the detection until the return light pulse can be accurately measured.

[0064] The light source 310 outputs a laser for irradiating an object in the field of view (FOV). The laser can be an infrared light having a wavelength in the range of 700nm to 1mm. The light source 310 can be, for example, a semiconductor-based laser (e.g., a diode laser) and / or an optical fiber-based laser. The semiconductor-based laser can be, for example, an edge-emitting laser (EEL), a vertical cavity surface-emitting laser (VCSEL), an external cavity diode laser, a vertical external cavity surface-emitting laser, a distributed feedback (DFB) laser, a distributed Bragg reflector (DBR) laser, an interband cascade laser, a quantum cascade laser, a quantum well laser, a double heterostructure laser, etc. An optical fiber-based laser is a laser in which the activation gain medium is an optical fiber doped with rare earth elements such as erbium, ytterbium, neodymium, dysprosium, praseodymium, thulium, and / or holmium. In some embodiments, the optical fiber laser is based on a double-clad optical fiber, in which the gain medium forms the core of an optical fiber surrounded by two layers of cladding. Double-clad fibers allow a high-power beam to be pumped into the core, enabling the laser source to become a high-power fiber laser source.

[0065] In some embodiments, the light source 310 includes a master oscillator (also called a seed laser) and a power amplifier (MOPA). The power amplifier amplifies the output power of the seed laser. The power amplifier can be a fiber amplifier, a bulk amplifier, or a semiconductor optical amplifier. The seed laser can be a diode laser (e.g., a Fabry-Perot cavity laser, a distributed feedback laser), a solid-state bulk laser, or an external cavity tunable diode laser. In some embodiments, the light source 310 can be an optically pumped microchip laser. A microchip laser is an alignment-free monolithic solid-state laser in which the laser crystal is directly in contact with the end mirror of the laser resonator. Microchip lasers are typically pumped by a laser diode (directly or using an optical fiber) to obtain the desired output power. Microchip lasers can be based on neodymium-doped yttrium aluminum garnet (Y3Al5O 12 ) laser crystal (i.e., Nd:YAG) or neodymium-doped vanadate (i.e., ND:YVO4) laser crystal. In some examples, light source 310 can have multiple amplification stages to achieve high power gain so that the laser output can have high power, thereby enabling the LiDAR system to have a long scanning range. In some examples, the power amplifier of light source 310 can be controlled so that the power gain can be changed to achieve any desired laser output power.

[0066] Figure 44 is a block diagram illustrating an exemplary fiber-based laser source 400 having a seed laser and one or more pumps (eg, laser diodes) for pumping a desired output power. Figure 3 An example of a light source 310 is shown. In some embodiments, the fiber-based laser source 400 includes a seed laser 402 to generate initial light pulses of one or more wavelengths (e.g., an infrared wavelength such as 1550 nm), which are provided to a wavelength division multiplexer (WDM) 404 via an optical fiber 403. The fiber-based laser source 400 further includes a pump 406 for providing laser power (e.g., a different wavelength, such as 980 nm) to the WDM 404 via an optical fiber 405. The WDM 404 multiplexes the light pulses provided by the seed laser 402 and the laser power provided by the pump 406 onto a single optical fiber 407. The output of the WDM 404 can then be provided to one or more preamplifiers 408 via the optical fiber 407. The preamplifier 408 can be an optical amplifier (e.g., having a gain of about 10-30 dB) that amplifies the optical signal. In some embodiments, the preamplifier 408 is a low noise amplifier. The preamplifier 408 outputs to the optical combiner 410 via an optical fiber 409. Combiner 410 combines the output laser of preamplifier 408 with the laser power provided by pump 412 via optical fiber 411. Combiner 410 can combine optical signals having the same wavelength or different wavelengths. An example of a combiner is a WDM. Combiner 410 provides the combined optical signal to boost amplifier 414, which produces output optical pulses via optical fiber 410. Boost amplifier 414 provides further amplification of the optical signal (e.g., another 20-40 dB). The output optical pulses can then be transmitted to transmitter 320 and / or steering mechanism 340 (e.g., Figure 3 It should be understood that Figure 4 An exemplary configuration of a fiber-based laser source 400 is shown. The laser source 400 may have a Figure 4 One or more components shown in and / or Figure 4 Many other configurations of different combinations of other components not shown (e.g., other components such as power supplies, lenses, filters, splitters, combiners, etc.).

[0067] In some variations, the fiber-based laser source 400 can be controlled (e.g., by control circuitry 350) to generate pulses of varying amplitudes based on the fiber gain profile of the optical fiber used in the fiber-based laser source 400. The communication path 312 couples the fiber-based laser source 400 to the control circuitry 350 (e.g., Figure 3350) so that the components of the fiber-based laser source 400 can be controlled by or otherwise communicate with the control circuit system. Alternatively, the fiber-based laser source 400 can include its own dedicated controller. Instead of the control circuit system 350 communicating directly with the components of the fiber-based laser source 400, the dedicated controller of the fiber-based laser source 400 communicates with the control circuit system 350 and controls and / or communicates with the components of the fiber-based laser source 400. The fiber-based laser source 400 may also include other components not shown, such as one or more power connectors, power sources, and / or power lines.

[0068] refer to Figure 3 , typical operating wavelengths of the light source 310 include, for example, about 850nm, about 905nm, about 940nm, about 1064nm, and about 1550nm. For laser safety, the upper limit of the maximum available laser power is set by the U.S. Food and Drug Administration (FDA) regulations. The optical power limit of the 1550nm wavelength is much higher than the optical power limits of the other wavelengths mentioned above. In addition, at 1550nm, the optical power loss in the optical fiber is very low. These characteristics of the 1550nm wavelength make it more conducive to long-distance LiDAR applications. The amount of optical power output from the light source 310 can be characterized by its peak power, average power, pulse energy, and / or pulse energy density. Peak power is the ratio of pulse energy to pulse width (e.g., full width at half maximum or FWHM). Therefore, for a fixed amount of pulse energy, a smaller pulse width can provide a larger peak power. The pulse width can be in the range of nanoseconds or picoseconds. The average power is the product of the pulse energy and the pulse repetition rate (PRR). As described in more detail below, PRR represents the frequency of the pulsed laser. In general, the smaller the time interval between pulses, the higher the PRR. The PRR generally corresponds to the maximum range that the LiDAR system can measure. The light source 310 can be configured to generate pulses with a high PRR to meet the desired number of data points in the point cloud generated by the LiDAR system. The light source 310 can also be configured to generate pulses with a medium or low PRR to meet the desired maximum detection distance. Wall plug efficiency (WPE) is another factor in evaluating the total power consumption, which can be a useful metric for evaluating the efficiency of the laser. For example, if Figure 1 As shown, multiple LiDAR systems can be attached to a vehicle, which can be an electric vehicle or a vehicle with limited fuel or battery power. Therefore, high WPE and intelligent ways of using laser power are often important considerations when selecting and configuring light sources 310 and / or designing laser delivery systems for vehicle-mounted LiDAR applications.

[0069] It should be understood that the above description provides non-limiting examples of light sources 310. Light source 310 can be configured to include many other types of light sources (e.g., laser diodes, short cavity fiber lasers, solid-state lasers, and / or external cavity tunable diode lasers) that are configured to generate one or more optical signals of various wavelengths. In some examples, light source 310 includes an amplifier (e.g., a preamplifier and / or a boost amplifier), which can be a doped fiber amplifier, a solid-state bulk amplifier, and / or a semiconductor optical amplifier. The amplifier is configured to receive and amplify the optical signal at a desired gain.

[0070] Return to reference Figure 3 , the LiDAR system 300 further includes a transmitter 320. The light source 310 provides laser light (e.g., in the form of a laser beam) to the transmitter 320. The laser light provided by the light source 310 can be an amplified laser with a predetermined or controlled wavelength, pulse repetition rate, and / or power level. The transmitter 320 receives the laser light from the light source 310 and emits the laser light to the steering mechanism 340 with a low divergence. In some embodiments, the transmitter 320 may include, for example, optical components (e.g., lenses, optical fibers, mirrors, etc.) for emitting one or more laser beams into the field of view (FOV) directly or via the steering mechanism 340. Although Figure 3 The transmitter 320 and the steering mechanism 340 are illustrated as separate components, but in some embodiments, they may be combined or integrated into a system. The steering mechanism 340 will be described in more detail below.

[0071] The laser beam provided by the light source 310 may diverge when it propagates to the emitter 320. Therefore, the emitter 320 generally includes a collimating lens, which is configured to collect the divergent laser beam and produce a more parallel beam with reduced or minimal divergence. The collimated beam can then be further directed through various optical devices, such as mirrors and lenses. The collimating lens can be, for example, a single plano-convex lens or a lens array. The collimating lens can be configured to achieve any desired characteristics, such as beam diameter, divergence, numerical aperture, focal length, etc. The beam propagation ratio or beam quality factor (also known as M 2 The M factor is used to measure the laser beam quality. In many LiDAR applications, it is important to have good laser beam quality in the generated transmitted laser beam. 2 The factor represents the degree of change of the beam relative to the ideal Gaussian beam. 2 The factor reflects how well a collimated laser beam can be focused on a small spot, or how well a divergent laser beam can be collimated. Thus, the light source 310 and / or the emitter 320 can be configured to meet, for example, scanning resolution requirements while maintaining a desired M 2 factor.

[0072] One or more of the light beams provided by the transmitter 320 are scanned to the FOV by the steering mechanism 340. The steering mechanism 340 scans the light beams in multiple dimensions (e.g., in the horizontal dimension and the vertical dimension) so that the LiDAR system 300 can map the environment by generating a 3D point cloud. The horizontal dimension can be a dimension parallel to the horizon or a surface associated with the LiDAR system or vehicle (e.g., a road surface). The vertical dimension is perpendicular to the horizontal dimension (i.e., the vertical dimension forms a 90-degree angle with the horizontal dimension). The steering mechanism 340 will be described in more detail below. The laser light scanned to the FOV may be scattered or reflected by objects in the FOV. At least a portion of the scattered light or reflected light forms the return light returned to the LiDAR system 300. Figure 3 An optical receiver and light detector 330 configured to receive the return light is further illustrated. The optical receiver and light detector 330 include an optical receiver configured to collect the return light from the FOV. The optical receiver may include optics (e.g., lenses, optical fibers, mirrors, etc.) for receiving, redirecting, focusing, amplifying, and / or filtering the return light from the FOV. For example, the optical receiver typically includes a collection lens (e.g., a single plano-convex lens or a lens group) to collect the return light and / or focus the collected return light onto the light detector.

[0073] The photodetector detects the return light focused by the optical receiver and generates a current and / or voltage signal proportional to the incident intensity of the return light. Based on such current and / or voltage signals, the depth information of the object in the FOV can be derived. An exemplary method for deriving such depth information is based on direct TOF (time of flight), which will be described in more detail below. The photodetector can be characterized by its detection sensitivity, quantum efficiency, detector bandwidth, linearity, signal-to-noise ratio (SNR), overload resistance, interference resistance, etc. Based on the application, the photodetector can be configured or customized to have any desired characteristics. For example, the optical receiver and the photodetector 330 can be configured so that the photodetector has a large dynamic range while having good linearity. The linearity of the photodetector indicates the ability of the detector to maintain a linear relationship between the input optical signal power and the detector output. A detector with good linearity can maintain a linear relationship within a large dynamic input optical signal range.

[0074] In order to achieve the desired detector characteristics, the structure of the photodetector and / or the material system of the detector can be configured or customized. Various detector structures can be used for the photodetector. For example, the photodetector structure can be a PIN-based structure having an undoped intrinsic semiconductor region (i.e., an "I" region) between the p-type semiconductor and the n-type semiconductor regions. Other photodetector structures include, for example, APD (avalanche photodiode)-based structures, PMT (photomultiplier tube)-based structures, SiPM (silicon photomultiplier tube)-based structures, SPAD (single photon avalanche diode)-based structures and / or quantum wires. For the material system used in the photodetector, Si, InGaAs and / or Si / Ge-based materials can be used. It should be understood that many other detector structures and / or material systems can be used in the optical receiver and the photodetector 330.

[0075] The photodetector (e.g., an APD-based detector) may have an internal gain so that the input signal is amplified when the output signal is generated. However, due to the internal gain of the photodetector, noise may also be amplified. Common types of noise include signal shot noise, dark current shot noise, thermal noise, and amplifier noise. In some embodiments, the optical receiver and photodetector 330 may include a preamplifier of a low noise amplifier (LNA). In some embodiments, the preamplifier may also include a transimpedance amplifier (TIA) that converts the current signal into a voltage signal. For linear detector systems, the input equivalent noise or noise equivalent power (NEP) measures the sensitivity of the photodetector to weak signals. Therefore, they can be used as an indicator of overall system performance. For example, the NEP of the photodetector specifies the power of the weakest signal that can be detected, and therefore it in turn specifies the maximum range of the LiDAR system. It should be understood that various photodetector optimization techniques can be used to meet the requirements of the LiDAR system 300. Such optimization techniques may include selecting different detector structures, materials, and / or implementing signal processing techniques (e.g., filtering, noise reduction, amplification, etc.). For example, in addition to or instead of direct detection using a return signal (e.g., by using ToF), coherent detection can also be used for a light detector. Coherent detection allows the amplitude and phase information of the received light to be detected by interfering the received light with a local oscillator. Coherent detection can improve detection sensitivity and noise immunity.

[0076] Figure 3The LiDAR system 300 is further illustrated to include a steering mechanism 340. As described above, the steering mechanism 340 guides the light beam from the transmitter 320 to scan the FOV in multiple dimensions. The steering mechanism is called a grating mechanism, a scanning mechanism, or simply a light scanner. Scanning the light beam in multiple directions (e.g., in the horizontal direction and the vertical direction) helps the LiDAR system to draw the environment by generating an image or a 3D point cloud. The steering mechanism can be based on mechanical scanning and / or solid-state scanning. Mechanical scanning uses a rotating mirror to steer the laser beam or physically rotate the LiDAR transmitter and receiver (collectively referred to as a transceiver) to scan the laser beam. Solid-state scanning guides the laser beam to various positions through the FOV without mechanically moving any macroscopic components, such as a transceiver. The solid-state scanning mechanism includes, for example, steering based on an optical phased array and steering based on a flash LiDAR. In some embodiments, because the solid-state scanning mechanism does not physically move the macroscopic components, the steering performed by the solid-state scanning mechanism can be referred to as effective steering. A LiDAR system using solid-state scanning may also be referred to as a non-mechanical scanning or simply a non-scanning LiDAR system (a flash LiDAR system is an exemplary non-scanning LiDAR system).

[0077] The steering mechanism 340 can be used with a transceiver (e.g., a transmitter 320 and an optical receiver and a light detector 330) to scan the FOV for generating an image or a 3D point cloud. As an example, to implement the steering mechanism 340, a two-dimensional mechanical scanner can be used with a single point or several single point transceivers. The single point transceiver transmits a single beam or a small number of beams (e.g., 2-8 beams) to the steering mechanism. The two-dimensional mechanical steering mechanism includes, for example, a polygon mirror, an oscillating mirror, a rotating prism, a rotating tilt mirror, a single plane or a multi-plane mirror, or a combination thereof. In some embodiments, the steering mechanism 340 may include a non-mechanical steering mechanism, such as a solid-state steering mechanism. For example, the steering mechanism 340 can be based on the tuned wavelength of a laser combined with a refraction effect, and / or based on a reconfigurable grating / phase array. In some embodiments, the steering mechanism 340 can use a single scanning device to achieve two-dimensional scanning, or use a combination of multiple scanning devices to achieve two-dimensional scanning.

[0078] As another example, to implement the steering mechanism 340, a one-dimensional mechanical scanner can be used with an array or a large number of single-point transceivers. Specifically, the transceiver array can be mounted on a rotating platform to achieve a 360-degree horizontal field of view. Alternatively, a static transceiver array can be combined with a one-dimensional mechanical scanner. The one-dimensional mechanical scanner includes a polygon mirror, an oscillating mirror, a rotating prism, a rotating tilt mirror, or a combination thereof to obtain a forward horizontal field of view. A steering mechanism using a mechanical scanner can provide robustness and reliability in mass production for automotive applications.

[0079] As another example, to implement the steering mechanism 340, a two-dimensional transceiver can be used to directly generate a scanned image or a 3D point cloud. In some embodiments, a stitching or micro-displacement method can be used to increase the resolution of the scanned image or the scanned field of view. For example, using a two-dimensional transceiver, a signal generated in one direction (e.g., horizontally) and a signal generated in another direction (e.g., vertically) can be integrated, interleaved, and / or matched to generate a higher or full resolution image or 3D point cloud representing the scanned FOV.

[0080] Some embodiments of the steering mechanism 340 include one or more optical redirecting elements (e.g., mirrors or lenses) that redirect the return light signal along the receive path (e.g., by rotation, vibration, or guidance) to direct the return light signal to the optical receiver and light detector 330. The optical redirecting elements that direct the light signal along the transmit path and the receive path can be the same component (e.g., shared), separate components (e.g., dedicated), and / or a combination of shared and separate components. This means that in some cases, the transmit path and the receive path are different, although they may partially overlap (or in some cases, substantially overlap or completely overlap).

[0081] Still reference Figure 3 , the LiDAR system 300 further includes a control circuit system 350. The control circuit system 350 can be configured and / or programmed to control various parts of the LiDAR system 300 and / or perform signal processing. In a typical system, the control circuit system 350 can be configured and / or programmed to perform one or more control operations, including, for example, controlling the light source 310 to obtain the desired laser pulse timing, pulse repetition rate and power; controlling the steering mechanism 340 (e.g., controlling speed, direction and / or other parameters) to scan the FOV and maintain pixel registration and / or alignment; controlling the optical receiver and light detector 330 (e.g., controlling sensitivity, noise reduction, filtering and / or other parameters) so that it is in an optimal state; and monitoring the overall system health / functional safety status (e.g., monitoring the safety of the laser output power and / or steering mechanism operation status).

[0082] The control circuit system 350 can also be configured and / or programmed to perform signal processing on the raw data generated by the optical receiver and light detector 330 to obtain distance and reflectivity information, and to package and communicate the data with the vehicle perception and planning system 220 (e.g., Figure 2For example, control circuit system 350 determines the time taken from transmitting a light pulse to receiving a corresponding return light pulse; determines when a return light pulse is not received for an transmitted light pulse; determines the direction (e.g., horizontal and / or vertical information) of the transmitted light pulse / return light pulse; determines an estimated range in a particular direction; derives reflectivity of objects in the FOV, and / or determines any other type of data related to LiDAR system 300.

[0083] The LiDAR system 300 can be set in a vehicle that can operate in many different environments, including hot or cold weather, rough road conditions that may cause strong vibrations, high or low humidity, dusty areas, etc. Therefore, in some embodiments, the optical and / or electronic components of the LiDAR system 300 (e.g., the optical devices in the transmitter 320, the optical receiver and light detector 330, and the steering mechanism 340) are arranged and / or configured in a manner to maintain long-term mechanical and optical stability. For example, the components in the LiDAR system 300 can be fixed and sealed so that they can operate under all conditions that the vehicle may encounter. As an example, a moisture-proof coating and / or an airtight seal can be applied to the optical components of the transmitter 320, the optical receiver and light detector 330, and the steering mechanism 340 (as well as other components susceptible to moisture). As another example, a housing, a cover, a fairing, and / or a window can be used in the LiDAR system 300 to provide desired properties, such as hardness, foreign object protection level (IP), self-cleaning ability, chemical resistance, and impact resistance. Additionally, efficient and economical methods for assembling the LiDAR system 300 may be used to meet LiDAR operational requirements while keeping costs low.

[0084] Those skilled in the art should understand that Figure 3 The above description is for illustrative purposes only, and the LiDAR system may include other functional units, blocks, or segments, and may include variations or combinations of the above functional units, blocks, or segments. For example, the LiDAR system 300 may also include Figure 3 Other components not shown in the diagram may include a power bus, power supplies, LED indicators, switches, etc. Additionally, there may be other connections between components, such as a direct connection between the light source 310 and the optical receiver and light detector 330 so that the light detector 330 can accurately measure the time from when the light source 310 emits a light pulse to when the light detector 330 detects a returning light pulse.

[0085] Figure 3The components are shown coupled together using communication paths 312, 314, 322, 332, 342, 352, and 362. These communication paths represent communications (bidirectional or unidirectional) between the various LiDAR system components, but are not necessarily the physical components themselves. Although communication paths can be implemented by one or more wires, buses, or optical fibers, communication paths can also be wireless channels or open-air optical paths so that no physical communication medium is present. For example, in one exemplary LiDAR system, communication path 314 includes one or more optical fibers; communication path 352 represents an optical path; and communication paths 312, 322, 342, and 362 are all wires that carry electrical signals. Communication paths can also include more than one of the above-mentioned types of communication media (e.g., they can include optical fibers and optical paths, or one or more optical fibers and one or more wires).

[0086] As mentioned above, some LiDAR systems use the time of flight (ToF) of light signals (e.g., light pulses) to determine the distance to objects in the light path. Figure 5A , an exemplary LiDAR system 500 includes a laser light source (e.g., a fiber laser), a steering mechanism (e.g., a system of one or more moving mirrors), and a light detector (e.g., a photodetector having one or more optical devices). The LiDAR system 500 can be implemented using, for example, the LiDAR system 300 described above. The LiDAR system 500 emits light pulses 502 along an optical path 504 determined by the steering mechanism of the LiDAR system 500. In the depicted example, the light pulses 502 generated by the laser light source are short pulses of laser light. In addition, the signal manipulation mechanism of the LiDAR system 500 is a pulse signal steering mechanism. However, it should be understood that the LiDAR system can operate by generating, emitting, and detecting non-pulsed light signals, and using techniques other than time of flight to derive the distance to objects in the surrounding environment. For example, some LiDAR systems use frequency modulated continuous waves (i.e., "FMCW"). It should also be understood that any of the techniques described herein for time-of-flight-based systems using pulsed signals can also be applied to LiDAR systems that do not use one or both of these techniques.

[0087] Return to reference Figure 5A(e.g., a time-of-flight LiDAR system using light pulses is illustrated), when light pulse 502 reaches object 506, light pulse 502 is scattered or reflected to form return light pulse 508. Return light pulse 508 may return to system 500 along optical path 510. The time from when the emitted light pulse 502 leaves LiDAR system 500 to when the return light pulse 508 returns to LiDAR system 500 may be measured (e.g., by a processor or other electronics within the LiDAR system, such as control circuitry 350). This time of flight, combined with knowledge of the speed of light, may be used to determine the distance / distance from LiDAR system 500 to the portion of object 506 where light pulse 502 was scattered or reflected.

[0088] By directing many light pulses, such as Figure 5B As depicted, LiDAR system 500 scans the external environment (e.g., by directing light pulses 502, 522, 526, 530 along optical paths 504, 524, 528, 532, respectively). Figure 5C As depicted, the LiDAR system 500 receives return light pulses 508, 542, 548 (corresponding to transmitted light pulses 502, 522, 530, respectively). The return light pulses 508, 542, and 548 are formed by scattering or reflecting the transmitted light pulses by one of the objects 506 and 514. The return light pulses 508, 542, and 548 may return to the LiDAR system 500 along optical paths 510, 544, and 546, respectively. Based on the direction of the transmitted light pulses (as determined by the LiDAR system 500) and the calculated distance from the LiDAR system 500 to the portion of the object that scattered or reflected the light pulses (e.g., the portion of objects 506 and 514), the external environment within the detectable range (e.g., the field of view between the paths 504 and 532, inclusive) may be accurately mapped or mapped (e.g., by generating a 3D point cloud or image).

[0089] If a corresponding light pulse is not received for a particular emitted light pulse, the LiDAR system 500 may determine that there is no object within the detectable range of the LiDAR system 500 (e.g., the object is outside the maximum scanning distance of the LiDAR system 500). Figure 5B In the example, light pulse 526 may not have a corresponding return light pulse (e.g. Figure 5C 528 within the detectable range of the LiDAR system 500).

[0090] exist Figure 5B , light pulses 502, 522, 526, and 530 may be emitted in any order, serially, in parallel, or based on other timings relative to each other. Additionally, although Figure 5B The emitted light pulses are depicted as being directed in one dimension or plane (e.g., the plane of the paper), but the LiDAR system 500 may also direct the emitted light pulses along other dimensions or planes. For example, the LiDAR system 500 may also direct the emitted light pulses in a direction perpendicular to the plane of the paper. Figure 5B The emitted light pulses are guided in the dimension or plane of the dimension or plane shown, thereby forming a 2-dimensional transmission of the light pulses. This 2-dimensional transmission of the light pulses can be performed point by point, line by line, once or in other ways. That is, the LiDAR system 500 can be configured to perform point scanning, line scanning, single scanning without scanning, or a combination thereof. A point cloud or image (e.g., a single horizontal line) from a 1-dimensional transmission of a light pulse can generate 2-dimensional data (e.g., (1) data from the horizontal transmission direction and (2) the range or distance to the object). Similarly, a point cloud or image from a 2-dimensional transmission of a light pulse can generate 3-dimensional data (e.g., (1) data from the horizontal transmission direction, (2) data from the vertical transmission direction, and (3) the range or distance to the object). Typically, a LiDAR system that performs n-dimensional transmission of light pulses generates (n+1)-dimensional data. This is because the LiDAR system can measure the depth of an object or the distance to an object, which provides an additional data dimension. Therefore, a 2D scan performed by a LiDAR system can generate a 3D point cloud that is used to map the external environment of the LiDAR system.

[0091] The density of a point cloud refers to the number of measurements (data points) per region performed by a LiDAR system. The point cloud density is related to the LiDAR scan resolution. Typically, at least for regions of interest (ROIs), a greater point cloud density is desired, and therefore a higher resolution is required. The point density in a point cloud or image generated by a LiDAR system is equal to the number of pulses divided by the field of view. In some embodiments, the field of view may be fixed. Therefore, in order to increase the density of points generated by a set of transmit-receive optical devices (or transceiver optical devices), the LiDAR system may need to generate pulses more frequently. In other words, the light source in the LiDAR system may have a higher pulse repetition rate (PRR). On the other hand, by generating and transmitting pulses more frequently, the farthest distance that a LiDAR system can detect may be limited. For example, if a return signal from a distant object is received after the system transmits the next pulse, the return signal may be detected in a different order from the order in which the corresponding signal was transmitted, resulting in ambiguity if the system cannot correctly associate the return signal with the transmitted signal.

[0092] To illustrate, consider an exemplary LiDAR system that can emit laser pulses with a pulse repetition rate between 500kHz and 1MHz. Based on the time it takes for the pulses to return to the LiDAR system, and to avoid confusion of return pulses from consecutive pulses in typical LiDAR designs, the maximum distance that the LiDAR system can detect can be 300 meters and 150 meters for 500kHz and 1MHz, respectively. The point density of a LiDAR system with a repetition rate of 500kHz is half that of 1MHz. Therefore, this example shows that if the system cannot correctly associate return signals that arrive out of order, increasing the repetition rate from 500kHz to 1MHz (and thus increasing the point density of the system) may reduce the detection range of the system. Various techniques are used to mitigate the tradeoff between higher PRR and limited detection range. For example, multiple wavelengths can be used to detect objects within different ranges. Optical and / or signal processing techniques (e.g., pulse coding techniques) are also used to associate between the emitted light signal and the returned light signal.

[0093] The various systems, devices, and methods described herein may be implemented using digital circuits or using one or more computers utilizing well-known computer processors, memory units, storage devices, computer software, and other components. Typically, a computer includes a processor for executing instructions and one or more memories for storing instructions and data. A computer may also include or be coupled to one or more mass storage devices, such as one or more magnetic disks, internal hard disks and removable disks, magneto-optical disks, optical disks, and the like.

[0094] The various systems, devices, and methods described herein can be implemented using computers operating in a client-server relationship. Typically, in such a system, a client computer is located remotely from a server computer and interacts via a network. The client-server relationship can be defined and controlled by computer programs running on the respective client and server computers. Examples of client computers may include desktop computers, workstations, portable computers, cellular smartphones, tablet computers, or other types of computing devices.

[0095] The various systems, apparatus, and methods described herein may be implemented using a computer program product tangibly embodied in an information carrier, such as in a non-transitory machine-readable storage device, for execution by a programmable processor; and the method procedures and steps may be implemented using one or more computer programs executable by such a processor. A computer program is a set of computer program instructions that can be used directly or indirectly in a computer to perform a specific activity or produce a specific result. A computer program may be written in any form of programming language, including compiled or interpreted languages, and it may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.

[0096] Figure 6 A simplified block diagram of an exemplary apparatus that can be used to implement the systems, apparatus, and methods described herein is illustrated. Apparatus 600 includes a processor 610 that is operably coupled to a persistent storage device 620 and a main memory device 630. Processor 610 controls the overall operation of apparatus 600 by executing computer program instructions that define these operations. The computer program instructions may be stored in persistent storage device 620 or other computer-readable medium and loaded into main memory device 630 when execution of the computer program instructions is desired. For example, processor 610 may be used to implement one or more components and systems described herein, such as control circuit system 350 ( Figure 3 As shown), vehicle perception and planning system 220 ( Figure 2 shown) and the vehicle control system 280 ( Figure 2 ). Therefore, the method steps discussed herein may be defined by computer program instructions stored in the main memory device 630 and / or the persistent storage device 620, and controlled by the processor 610 executing the computer program instructions. For example, the computer program instructions may be implemented as a computer executable code programmed by a person skilled in the art to execute the algorithm defined by the method steps discussed herein. Therefore, by executing the computer program instructions, the processor 610 executes the algorithm defined by the method steps discussed herein. The device 600 also includes one or more network interfaces 680 for communicating with other devices via a network. The device 600 may also include one or more input / output devices 690 that enable a user to interact with the device 600 (e.g., a display, keyboard, mouse, speaker, buttons, etc.).

[0097] The processor 610 may include general and special purpose microprocessors and may be the sole processor of the device 600 or one of multiple processors. The processor 610 may include one or more central processing units (CPUs) and one or more graphics processing units (GPUs), which may, for example, work separately from the one or more CPUs and / or perform multitasking with the one or more CPUs to accelerate processing, for example, for various image processing applications described herein. The processor 610, the persistent storage device 620, and / or the main memory device 630 may include one or more application specific integrated circuits (ASICs) and / or one or more field programmable gate arrays (FPGAs), or may be supplemented by one or more ASICs and / or one or more FPGAs, or may be incorporated into one or more ASICs and / or one or more FPGAs.

[0098] The persistent storage device 620 and the main memory device 630 each include a tangible, non-transitory computer-readable storage medium. The persistent storage device 620 and the main memory device 630 may each include a high-speed random access memory, such as a dynamic random access memory (DRAM), a static random access memory (SRAM), a double data rate synchronous dynamic random access memory (DDR RAM), or other random access solid-state memory devices, and may include non-volatile memory, for example, one or more disk storage devices, such as internal hard disks and removable disks, magneto-optical disk storage devices, optical disk storage devices, flash memory devices, semiconductor storage devices (such as erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)), compact disk read-only memory (CD-ROM), digital versatile disk read-only memory (DVD-ROM) disks, or other non-volatile solid-state storage devices.

[0099] Input / output devices 690 may include peripheral devices such as printers, scanners, display screens, etc. For example, input / output devices 690 may include a display device (such as a cathode ray tube (CRT), plasma or liquid crystal display (LCD) monitor, keyboard) for displaying information to a user, and a pointing device (such as a mouse or trackball) that a user may use to provide input to apparatus 600.

[0100] Any or all of the functionality of the systems and devices discussed herein may be performed by the processor 610, and / or incorporated into a device or system such as the LiDAR system 300. Additionally, the LiDAR system 300 and / or device 600 may utilize one or more neural networks or other deep learning techniques performed by the processor 610 or other systems or devices discussed herein.

[0101] Those skilled in the art will recognize that the actual computer or computer system implementation may have other structures and may also include other components, and Figure 6 is a simplified representation of some of the components of such a computer for purposes of illustration.

[0102] Micro-electromechanical system (MEMS) mirrors are used in LiDAR systems for laser beam steering. Compared to steering mechanisms involving rotating mirrors and polygonal structures, MEMS mirrors offer advantages such as reduced size and increased scanning speed. In addition, in a MEMS device, while the mirror plate moves to steer the light, the rest of the components of the MEMS device remain stationary. This enhances the reliability and stability of the MEMS device.

[0103] Electromagnetic MEMS mirrors operate on the principle of the Lorentz force, which is the force that charged particles experience when moving in a magnetic field. Figure 7 The diagram shows the Lorentz force on a current-carrying conductor in a magnetic field. "N" (711) depicts the north pole of a permanent magnet. "S" (712) depicts the south pole of a permanent magnet. "B"

[0104] (730) depicts a magnetic field flowing from the North Pole to the South Pole. Conductor 720 is located between the North Pole and the South Pole. When a current "I" (721) flows through conductor 720 in the direction shown, a Lorentz force "F" (740) is applied to conductor 720. The Lorentz force is the result of the interaction between the electric force exerted by the electric field and the magnetic force exerted by the magnetic field on the moving electrons in conductor 720. The direction of the Lorentz force "F" follows Fleming's left-hand rule, as indicated by symbol 701. Using the left hand according to Fleming's left-hand rule, if the index finger points in the direction of the magnetic field "B", and if the middle finger points in the direction of the current "I", the thumb will point in the direction of the Lorentz force "F" acting on the conductor. Therefore, in Figure 7 , based on the left-hand rule, the Lorentz force "F" (740) applied on the conductor 720 points in an upward direction.

[0105] The magnitude of the Lorentz force acting on the current-carrying conductor 720 can be obtained by the following formula (1):

[0106] |F| = |I · L · B · sin(θ)| (1)

[0107] In the above formula (1), "F" represents the Lorentz force acting on the current-carrying conductor, "I" represents the current flowing through the conductor, "L" represents the length of the conductor segment in the magnetic field, "B" represents the magnitude of the magnetic field, in Tesla, and "θ" represents the angle between the direction of the current and the direction of the magnetic field. Formula (1) indicates that the magnitude of the Lorentz force applied to the current-carrying conductor is proportional to the magnitude of the current and proportional to the magnitude of the magnetic field. This means that increasing the current or magnetic field strength will result in a larger Lorentz force acting on the conductor. Additionally, the angle between the direction of the current and the direction of the magnetic field affects the Lorentz force because the force is maximum when the current and the magnetic field are perpendicular to each other (θ = 90 degrees). When the current is parallel to the magnetic field (θ = 0 or 180 degrees), the Lorentz force becomes zero, so that no Lorentz force acts on the conductor.

[0108] Fig. 8A An exemplary MEMS mirror device 800 is illustrated according to one embodiment. The MEMS mirror device 800 is a movable scanner device and can be used to implement Figure 3 At least a portion of the steering mechanism 340 shown. For example, a MEMS mirror device 800 can be used instead of using a macroscopic movable mirror, such as a polygon mirror and a galvanometer mirror. In other examples, the MEMS mirror device 800 can be used to replace a portion of the steering mechanism 340, such as a galvanometer mirror. In one embodiment, the MEMS mirror device 800 includes a support frame 810, a first arm 860, a second arm 861, a MEMS mirror 850, and a platform 851. The support frame 810 can be made of metal, plastic, rubber, carbon fiber, or a composite material, etc. In some embodiments, the support frame 810 includes one or more permanent magnets that form a north pole (841) and a south pole (842). In Fig. 8A In some embodiments, one or more permanent magnets form part of the support frame 810. In some embodiments, the permanent magnets are partially or completely independent of or separate from the support frame 810. For example, the permanent magnets can be physically attached to the support frame 810 but not part of the support frame 810. In other examples, the permanent magnets can be physically separated from the support frame 810.

[0109] In one embodiment, the MEMS mirror 850 is circular in shape and is positioned at the center of the square-shaped platform 851. In other embodiments, the MEMS mirror 850 may have an elliptical shape, a polygonal shape, or any other shape; and the platform 851 may have a circular shape, an elliptical shape, a polygonal shape, or any other shape. The MEMS mirror 850 and the platform 851 may have similar shapes (e.g., both have circular shapes) or different shapes (e.g., one has a circular shape and one has an elliptical shape). The centers of the MEMS mirror 850 and the platform 851 may be the same or different. In one example, the MEMS mirror 850 and the platform 851 may be concentric or eccentric.

[0110] The MEMS mirror 850 includes a reflective surface that can reflect light. The platform 851 may include a metal-based substrate to provide mechanical support for the MEMS mirror 850. The MEMS mirror 850 and the platform 851 may be mechanically, adhesively, magnetically coupled together (e.g., using screws, fasteners, grooves, clips, brackets, etc.), or they may form an integral piece.

[0111] In some embodiments, at least a portion of the platform 851 includes a film substrate. The film substrate can be made of glass, ceramic, plastic, polyester, crystal, metal or composite materials, etc. The film substrate includes or is physically coupled to a first arm 860 and a second arm 861. The first arm 860 and the second arm 861 are also referred to as the left arm and the right arm because they are shown as being positioned on the left and right sides of the platform 851, respectively. In some examples, the first arm 860 and the second arm 861 are integrated with the platform 851 so that they form a single piece. In other examples, the first arm 860 and the second arm 861 are detachable from the platform 851. In one embodiment, a conductive coil 830 is positioned around the left arm 860 and the platform 851. The conductive coil 830 is electrically coupled to a power source, such as a current source or a voltage source ( Fig. 8A ) to receive a current or voltage input. The power supply can be Figure 3 It is shown as part of the control circuitry 350 or as a separate power supply.

[0112] When current "I" (823 and 820) flows through conductive coil 830, opposing Lorentz forces are applied to the upper and lower portions of platform 851, causing platform 851 to rotate. Fig. 8A As shown, the magnetic field B (821) flows from the north pole 841 to the south pole 842. When the current "I" (823) flows toward the right direction in the upper portion of the platform 851, based on Fleming's left-hand rule, the upward-directed Lorentz force "F" (824) is applied to the upper portion of the platform 851. On the other hand, when the current "I"

[0113] When current (820) flows in the left direction in the lower portion of the platform 851, a downwardly directed Lorentz force "F" (822) is applied to the lower portion of the platform 851. The combined forces of 824 and 822 produce a torque, thereby causing the platform 851 to rotate along the rotation axis 801 in the direction of 802. Similarly, when current flows in the opposite direction in the conductive coil 830, the platform 851 rotates in the opposite direction. By changing the direction and / or magnitude of the current, the platform 851 can swing between two positions.

[0114] In some embodiments, the left arm 860 and the right arm 861 are rotatably coupled to the support frame 810 via, for example, bearings (not shown), so that the support frame 810 does not move when the platform 851 rotates or swings. In other embodiments, the left arm 860 and the right arm 861 are fixedly coupled to the support frame 810 so that when the platform 851 moves, the support frame 810 also moves. In other embodiments, the left arm 860 and the right arm 861 are rotatably coupled to the platform 851 so that the platform 851 can move relative to the arms 860 and 861.

[0115] Arms 860 and 861 support platform 851 to maintain its position and enable platform 851 to rotate or swing along axis 801. Arms 860 and 861 overlap axis 801. In some embodiments, arms 860 and 861 do not overlap axis 801. In some embodiments, arms 860 and 861 are parallel to each other. In one embodiment, there is only one arm for supporting platform 851. In some embodiments, arms 860 and 861 are implemented as torsion bars. Arms 860 and 861 are not only used as rotation axes, but also as torsion springs to inhibit the rotation of the mirror. As previously described, when current flows through conductive coil 830 in a specific direction, the current generates torque, thereby starting the rotation of platform 851. At the same time, the torsion bar spring applies elastic force in the opposite direction, thereby resisting the rotation force. When the two forces reach a state of equilibrium, the rotation of platform 851 stops. The stop position corresponds to the angular position of MEMS mirror 850. The MEMS mirror 850 can be controlled to stop at various angular positions by adjusting the direction and magnitude of the current flowing through the conductive coil 830. The maximum angular range that a MEMS mirror platform can achieve is referred to as the field of view of the MEMS mirror device.

[0116] Fig. 8A The illustrated MEMS mirror device 800 can rotate or tilt in only one dimension along axis 801. In other embodiments, the MEMS mirror device can have the ability to move or tilt in more than one axis and in more than one dimension. Figure 8BAn exemplary two-dimensional MEMS mirror device 811 according to one embodiment is illustrated. Device 811 is similar to device 800, but differs in several aspects. Compared to device 800, device 811 includes a separate conductive coil 831 located on a support platform 810. Device 811 also includes two additional arms 862 and 863, which enable the support frame 810 to rotate or tilt along axis 803 in the direction of 804 or the opposite direction. Magnetic field B (825) flows diagonally toward support frame 810. In other embodiments, magnetic field 825 can flow toward support frame 810 from other directions. Since magnetic field 825 produces different angles "θ" in different sections of coils 830 and 831, based on formula (1), the diagonally positioned magnetic field 825 enables the Lorentz force to act on both coils 830 and 831. In some embodiments, the current flowing in each section of coils 830 and 831 can be controlled separately. When the support frame 810 rotates along the axis 803, the platform 851 may also rotate along the axis 801, thus producing a two-dimensional movement of the mirror 850. By controlling the degree of rotation or tilt of the mirror 850 along two axes, the FOV of the LiDAR system can be extended to cover a wider angular range in two or more dimensions, for example, in both the vertical and horizontal directions.

[0117] Return to reference Fig. 8A In some embodiments, the coil 830 can be electrically coupled to a controller configured to regulate the current flowing through the coil 830. The controller can be Figure 3The controller 851 may be a part of the control circuit system 350 shown or may be an independent circuit. The controller may be configured to control various aspects of the current flowing through the coil 830, such as amplitude, intensity or direction. The controller may manage the voltage, power or resistance of the coil 830. In the case where the current is an alternating current (AC), the controller may control the frequency, phase or impedance of the current, etc. By controlling these parameters, the controller may control the angular position and / or movement speed of the platform 851. Therefore, the controller may manage the frame rate, scanning speed, scan line density or region of interest (ROI) of the frame. For example, the controller may control the current flowing through the coil 830 so that the platform 851 may rotate continuously or incrementally. When performing incremental rotation, the platform 851 stops for a short period of time at each specific stoppable position. The resolution of the angular movement may be fine-tuned by the controller. When the platform 851 moves in the vertical dimension of the FOV, the controller may increase the frame rate or scanning speed by increasing the vertical movement speed of the platform 851. In order to increase the vertical scan line density within the entire frame or ROI, the controller may reduce the vertical movement speed of the platform 851. When the platform 851 moves in the horizontal dimension of the FOV, the controller can increase the horizontal scan resolution within the entire frame or ROI by reducing the horizontal movement speed of the platform 851. The controller can also increase the frame rate by increasing the horizontal movement speed of the platform 851. For a two-dimensional MEMS mirror device, the controller can control the movement speed of the platform 851 in both the horizontal direction and the vertical direction at the same time. For example, the controller can increase the horizontal movement speed to increase the frame rate while reducing the vertical movement speed to increase the scan line density. In some cases, this can enable the controller to maintain the frame rate while increasing the scan line density in one or more ROIs within the frame.

[0118] Fig.9A and Fig. 9B Illustrated are top and cross-sectional views of an exemplary MEMS mirror device 900 according to one embodiment. Fig.9A A top view of a MEMS mirror device 900 is shown. Fig. 9B The MEMS mirror device 900 is shown along Fig.9A The MEMS mirror device 900 is a movable scanner device and can be used to implement Figure 3 At least a portion of the steering mechanism 340 is shown. The MEMS mirror device 900 includes a mirror 950, a platform or substrate 920, a left arm 960, a right arm 961, magnets 941-946, and a coil 930.

[0119] Platform 920 is similar to Fig. 8AThe platform 920 is square in shape and serves as a substrate for the MEMS mirror 950. The platform 920 is sometimes interchangeably referred to as a substrate 920 or a membrane substrate 920. In some embodiments, the platform 920 includes a support material, such as a plastic material, to provide additional structural support to the substrate. In some embodiments, the MEMS mirror device 900 includes a substrate similar to Fig. 8A The support frame 810 of the support frame 950 is not shown in FIG. 9 . The mirror 950 may be a partial reflective mirror or a total reflective mirror and is attached to the top of the substrate 920 . As the substrate 920 , a relatively thin film material is used.

[0120] An electrical winding or toroidal coil 930 is mounted in the substrate 920. In one embodiment, the toroidal coil 930 is wound on a flat surface. In one embodiment, the coil 930 is disposed around the periphery of the mirror 950, and no portion of the coil 930 is disposed under the mirror 950. In other embodiments, at least a portion of the coil 930 is disposed under the mirror 950 (not shown in FIG. 9 ). The coil 930 is coupled to a power source via an arm 960. In some embodiments, the coil 930 is coupled to a power source via an arm 961 or via both arms 960 and 961. In some embodiments, the coil 930 is coupled to a power source via an electrical node located on one or both arms. In some embodiments, the electrical node is located on a support frame of the MEMS mirror device 900 (not shown in FIG. 9 ). In some embodiments, the coil 930 is a toroidal coil and is formed along the edge of the membrane substrate 920.

[0121] In some embodiments, arms 960 and 961 are implemented as torsion bars. As previously described, the angular position of mirror 950 or platform 920 corresponds to the stop position where the torque and elastic force of the torsion bar spring reach a balance. The platform 920 can be controlled to stop at different angular positions in its field of view by adjusting the direction and magnitude of the current in coil 930. Various movement requirements can be arranged for platform 920. For example, platform 920 may be required to rotate continuously from one angular position to the next angular position without interruption. Platform 920 may also need to rotate incrementally, thereby stopping at a specific stoppable position for a short period of time. The resolution of angular movement may vary, such as 1 degree, 0.1 degree, 0.01 degree, 0.001 degree or any other incremental value. Platform 920 may also need to rotate at a certain angular velocity, such as 70 degrees per second or 120 degrees in 0.1 seconds, etc. Platform 920 may also need to maintain an average angular velocity or limit its rotation to a maximum angular velocity.

[0122] Specific features of the coils and / or magnets, such as the number of windings in coil 930, their size, and the size of the magnets (e.g., magnets 941-946) can be configured to meet the movement requirements of platform 920. For example, equation (1) describes the Lorentz force acting on a segment of the coil based on the length of the conductor within the magnetic field. Therefore, increasing the number of windings in coil 930 will cause the Lorentz force applied to platform 920 to increase proportionally. This therefore increases the maximum angular velocity of mirror 950 and / or expands the maximum angular range (thereby expanding the field of view). In addition, because the Lorentz force is proportional to the magnetic field strength, increasing the size of the magnet or the magnet grade will also increase the maximum angular velocity of mirror 950 and / or allow a wider field of view. The movement requirements of platform 920 can also be determined by Figure 3 The control circuit system 350 shown controls For example, the control circuit system 350 can adjust the magnitude and incremental value of the current flowing in the coil 930 so that continuous or incremental rotation of the platform 920 can be precisely controlled.

[0123] exist Fig.9A In the embodiment shown, six permanent magnets 941-946 are located near the four edges of the platform 920. The distance between the permanent magnets and the edge of the platform 920 can be configured based on the desired magnetic field and force. The shorter the distance between the opposite magnetic poles, the stronger the magnetic field between the magnetic poles. The permanent magnets are not physically attached to the platform 920, the substrate 920 or the mirror 950. In the discussion herein, the "upper" half or "lower" half of the platform 920 refers to the half divided relative to line 9B. The four edges of the platform 920 include the upper edge (the edge closer to the magnet 941), the lower edge (the edge closer to the magnet 942), the left edge (the edge closer to the magnet 943 and 945) and the right edge (the edge closer to the magnet 944 and 946). Arm 960 is attached to the left edge of the platform 920 at a substantially central position. Arm 961 is attached to the right edge of the platform at a substantially central position. The total number of permanent magnets used in the MEMS mirror device 900 can vary and can exist in any number. In addition, the number of magnets located on each side of platform 920 may also be different. In addition, the polarity of each magnet may be different from the polarity currently shown in Figure 9. Platform 920 is square in shape. In some embodiments, platform 920 may adopt alternative shapes, such as triangle, rectangle, parallelogram, hexagon or any other polygonal form. Additionally, platform 920 may also present a circular shape or an elliptical shape. In some embodiments, platform 920 and mirror 950 may have the same shape. In other embodiments, they may have different shapes.

[0124] Permanent magnets 941 and 942 are respectively disposed near the upper and lower edges of the platform 920. Fig. 8A9B. The north pole of magnet 941 is closer to the upper edge of platform 920 than its south pole. The south pole of magnet 942 is closer to the lower edge of platform 920 than its north pole. In this configuration, the north pole of magnet 941 faces the south pole of magnet 942, thereby generating a magnetic field that flows from 941 to 942 and passes through the horizontal coils located on the upper and lower halves of platform 920. Based on Fleming's left-hand rule, the Lorentz force acts on the upper half of platform 920, pointing inward perpendicular to the paper (away from the reader and into the paper). In contrast, the Lorentz force acting on the lower half of platform 920 points outward to the reader. These combined forces cause platform 920 to rotate around the axis defined by line 9B. In some embodiments, arms 960 and 961 are aligned with the axis of line 9B. When the current flows in the reverse direction, platform 920 can rotate or swing in the reverse direction.

[0125] Four side magnets 943-946 are positioned adjacent to the left and right edges of the platform 920, with magnets 943 and 945 located near the left edge, and magnets 944 and 946 located near the right edge. These side magnets are used to enhance the Lorentz force applied to the upper and lower halves of the platform 920, thereby achieving faster rotation and / or a wider angular range. Taking a pair of side magnets 943 and 944 in the upper half of the platform 920 as an example, the north pole of magnet 943 is closer to the left edge of the platform 920 than its south pole. The north pole of magnet 944 is closer to the right edge of the platform 920 than its north pole. In this configuration, the north pole of magnet 943 faces the north pole of permanent magnet 944 on the opposite side. Since their polarities are opposite to each other, there is no direct magnetic field flowing from magnet 943 to magnet 944. However, in the local area around magnet 943, the magnetic field flows through the coil 930 on the left. Although the magnetic field may not be perpendicular to the direction of the current (θ in equation (1) is not 90 degrees), it still produces a weaker Lorentz force acting on the nearby coil. The same applies to the magnetic field in the area near magnet 944. Applying Fleming's left-hand rule, the two magnetic fields cause two Lorentz forces to point inward perpendicular to the paper.

[0126] Conversely, the south pole of magnet 945 faces the south pole of magnet 946 on the opposite side. Similarly, the opposite polarity of magnets 945 and 946 generates two magnetic fields, which causes the Lorentz force on the nearby coils to point outward toward the reader. Since the Lorentz forces exerted by the side magnets 943-946 are in approximately the same direction as the Lorentz forces exerted by the two main magnets 941 and 942, the side magnets serve to enhance the Lorentz forces exerted by magnets 941 and 942. In some embodiments, some or all of magnets 941-946 are electromagnets.

[0127] Substrate 920 can be made of metal-based materials. In order to prevent interference with the magnetic field generated by the surrounding magnets, the film substrate material should be non-magnetic, excluding iron, cobalt and nickel. In order to insulate the coil 930 from the metal-based substrate, the coil can be coated. Various materials such as polyimide, polyvinyl chloride or polyester film can be used for the sheath of the coil 930 in the substrate 920. For the part of the coil 930 located outside the substrate 920 (for example, located in the arm 960), the sheath may not be necessary. In some embodiments, the entire part of the coil 930 can be coated.

[0128] Metal-based MEMS substrates offer several advantages over silicon-based substrates. Metal-based MEMS substrates offer higher mechanical strength, resulting in more robust and durable MEMS mirrors. Metals have higher flexibility compared to silicon, which is a brittle material. Flexibility allows metal-based MEMS substrates to bend or deform without breaking, making them more resilient to mechanical stress. In contrast, silicon-based substrates are prone to cracking or breaking under such conditions.

[0129] Metal-based MEMS substrates enable larger mirror sizes and longer scanning distances. In some LiDAR systems, larger scanning mirrors help extend the scanning distance. When the scanning mirror has a larger surface area, the mirror has a larger optical aperture. The larger optical aperture, in turn, allows the LiDAR receiver to detect weaker return light signals from objects located at a greater distance. Using silicon as a MEMS substrate limits the size of the mirror because larger rotating mirrors made of silicon may be more easily damaged. On the other hand, using metal as a MEMS substrate facilitates the manufacture of larger-sized MEMS mirrors because metal-based substrates have better resistance to mechanical stress, vibration, and shock.

[0130] Metal-based MEMS mirrors also offer advantages that facilitate larger mirror sizes for cost considerations. When silicon-based MEMS mirrors are manufactured on silicon wafers, it is important to achieve high yields due to the expensive nature of silicon wafers. Therefore, silicon-based MEMS chips are typically designed to be smaller in size, aiming to achieve higher yields. For example, a typical silicon-based MEMS mirror has a diameter of no more than 7 mm. On the other hand, the use of metal as a MEMS substrate allows the production of larger-sized MEMS chips. In some embodiments, the mirror size of a metal-based MEMS mirror can be one inch or larger. Compared to the limitations imposed by expensive silicon-based substrates, the cost-effectiveness of metal-based substrates makes it affordable to manufacture larger chips, even at lower yields.

[0131] In some embodiments, the film substrate 920 can be flexible or elastic. The film substrate 920 can also be made of a polymer-based material. In some embodiments, the metal-based film substrate 920 has a thickness of about 1 nanometer to 100 centimeters.

[0132] Mirror 950 requires a rigid structure to effectively withstand mechanical stress. Using a rigid material for mirror 950 provides the necessary structural stability, which is important for a robust MEMS mirror. The continuous rotation or swinging experienced by MEMS mirrors may subject them to mechanical stress. By using a rigid material for mirror 950, the MEMS mirror can maintain its shape, resist deformation, and thereby maintain the performance and life of the mirror. Silicon or glass can be used as the material for mirror 950.

[0133] In some embodiments, to enhance the rigidity of the mirror 950, a rigid metal sheet may be attached to the side of the mirror 950 and mounted on top of the coil 930. Likewise, to prevent the sheet metal from interfering with the magnetic field, a non-magnetic metal (excluding iron, cobalt, and nickel) may be used as the material of the sheet metal. In addition, the surface of the mirror 950 does not necessarily require coating or special treatment.

[0134] Fig. 10A 1 is a block diagram illustrating an exemplary arrangement of components in a steering mechanism 1000 of a LiDAR system according to one embodiment. Figure 3 The steering mechanism 1000, similar to the steering mechanism 340 illustrated in FIG. 1 , directs a beam from the transceiver 1030 to scan the FOV in multiple dimensions (e.g., in the horizontal and vertical dimensions). The steering mechanism 1000 includes a movable scanner device 1001. In some embodiments, the movable scanner device 1011 may be Fig. 8A The MEMS mirror device 800 shown in Figure 9 or the MEMS mirror device 900 shown in Figure 9. In some embodiments, the movable scanner device 1011 is a two-dimensional MEMS mirror device.

[0135] The transceiver 1030 is Figure 3 The transmitter 320 is shown in combination with an optical receiver and a light detector 330. Figure 3 As shown, the transmitter 320 receives laser light from the light source 310 and transmits the laser light to the steering mechanism 340 via the communication path 332. Fig. 10A , laser light from emitter 320 via communication path 332 is depicted as outgoing beam 1021. Outgoing beam 1021 is directed to movable scanner device 1011, and then directed by movable scanner device 1011 to illuminate object 1050 in FOV. As a two-dimensional MEMS mirror, movable scanner device 1011 can scan in both horizontal and vertical directions.

[0136] The mobile scanner device 1011 is used to emit a light beam to illuminate an object in the FOV and to receive return light and redirect the return light to the transceiver 1030. When the outgoing light beam 1021 travels to illuminate the object 1050 in the FOV, at least a portion of the light beam is reflected or scattered by the object 1050 to form return light 1031. The return light 1031 is received by the mobile scanner device 1011 and then transmitted by the mobile scanner device 1011 via the communication path 352 (e.g., Figure 3 As shown) is redirected (e.g., reflected) to transceiver 1030.

[0137] The function of the control circuit system 1040 is similar to Figure 3 The control circuit system 1040 shown. In this regard, the control circuit system 350 establishes communication with the steering mechanism 340 via the communication path 342. Similarly, the control circuit system 1040 is designed to manage the movable scanner device 1011 via the communication path 1042. For example, it adjusts the current flowing in the coils of the movable scanner device 1011 (e.g., the coils 830 of the MEMS mirror device 800 or the coils 930 of the MEMS mirror device 900) to manage the speed and angular position of the MEMS mirror. Additionally, the control circuit system 1040 receives feedback from the movable scanner device 1011 regarding the actual mirror speed and position. Based on the feedback, it adjusts the magnitude and incremental value of the current flowing in the coils to fine-tune the movement and / or position of the mirror.

[0138] The power supply 1020 is coupled to the coil of the movable scanner device 1011 to provide power for the current flowing in the coil. The power supply 1020 can be a stand-alone power supply or a part of the control circuit system 1040. In some embodiments, the power supply 1040 is controlled by the control circuit system 1040.

[0139] Fig. 10B 1 is a block diagram illustrating an exemplary arrangement of components in a steering mechanism 1001 of a LiDAR system according to one embodiment. The steering mechanism 1001 is identical to the steering mechanism 1000, except that the steering mechanism 1001 includes an additional second mirror 1012. The second mirror 1012 may be another MEMS mirror, a polygonal mirror, an oscillating mirror, a galvanometer mirror, a rotating prism, a rotating tilt mirror surface, or a single or multi-plane mirror, etc. The second mirror 1012 may include a plurality of the foregoing mirrors or a combination thereof.

[0140] In the steering mechanism 1001, the movable scanner device 1011 can scan in only one direction, and the second mirror 1012 can scan in another direction. For example, the movable scanner device 1011 can scan in the vertical direction of the FOV, and the second mirror 1012 can scan in the horizontal direction of the FOV. In other embodiments, the movable scanner device 1011 can scan in the horizontal direction, and the second mirror 1012 can scan in the vertical direction of the FOV. Fig. 10A The steering mechanism 1000 is different in Fig. 10A In the embodiment of the steering mechanism 1001, only the movable scanner device scans and receives light, and in the steering mechanism 1001, the outgoing light beam 1021 is directed to the movable scanner device 1011. From the movable scanner device, the outgoing light beam is reflected by the movable scanner device 1011 toward the second mirror 1012, and then the second mirror 1012 directs the light to illuminate the object 1050 in the FOV. In other embodiments of the steering mechanism 1001, the positions of the movable scanner device 1011 and the second mirror 1012 can be interchanged.

[0141] The movable scanner device 1011 and the second mirror 1012 are both used to emit a light beam to illuminate an object in the FOV, and to receive return light and redirect the return light to the transceiver 1030. When the outgoing light beam 1021 travels to illuminate the object 1050 in the FOV, at least a portion of the light beam is reflected or scattered by the object 1050 to form return light 1031. The return light 1031 is received by the second mirror 1012 and redirected (e.g., reflected) by the second mirror 1012 to the movable scanner device 1011. The return light 1031 is then transmitted by the movable scanner device 1011 via the communication path 352 (e.g., Figure 3 ) to the transceiver 1030. In some embodiments, the control circuit system 1040 also controls the second mirror 1012 and / or the power supply 1020 ( Fig. 10B not shown).

[0142] The foregoing description should be understood to be illustrative and exemplary in every respect, rather than restrictive, and the scope of the invention disclosed herein is not determined by the description, but by the claims interpreted in accordance with the full breadth allowed by the patent law. It should be understood that the embodiments shown and described herein are merely illustrative of the principles of the invention, and that various modifications may be made by those skilled in the art without departing from the scope and spirit of the invention. Various other feature combinations may be implemented by those skilled in the art without departing from the scope and spirit of the invention.

Claims

1. An electromagnetic movable scanner device for performing optical scanning for use in a light ranging and detection (LiDAR) system, the device comprising: a platform comprising a membrane substrate, the platform being pivotable about an axis; a reflector, the reflector being disposed on the platform; a plurality of magnets disposed proximate to and spaced apart from one or more edges of the film substrate; and one or more electrical windings mounted on the platform, at least a portion of the electrical windings being disposed below the reflector, wherein when the one or more electrical windings carry an electric current, the interaction between the magnetic fields formed by the plurality of magnets and the electrical windings is operable to electromagnetically move the reflector to: Scanning the transmitted light into the field of view of the LiDAR system along at least one direction; as well as Return light is received from the field of view, the return light being formed based on the transmitted light. 2 . The apparatus of claim 1 , wherein the film substrate of the platform is made of a metal-based material. 3 . The apparatus of claim 2 , wherein the metal-based material of the substrate comprises a non-magnetic metal material. 4 . The apparatus of claim 3 , wherein the non-magnetic metal material comprises a metal material other than iron, nickel or cobalt.

5. The apparatus of any one of claims 1 to 4, wherein the film substrate of the platform has a thickness of approximately 1 nm to 100 cm.

6. The apparatus according to any one of claims 1 to 5, wherein the film substrate of the platform is made of a polymer-based material.

7. The apparatus according to any one of claims 1 to 6, wherein the film substrate of the platform is a rigid substrate.

8. The apparatus according to any one of claims 1 to 7, wherein the film substrate of the platform is a flexible substrate.

9. The apparatus of any one of claims 1 to 8, wherein the reflector has substantially the same shape as the film substrate.

10. The apparatus of any one of claims 1 to 9, wherein the reflector has a different shape than the film substrate.

11. The apparatus according to any one of claims 1 to 10, wherein at least one of the reflector and the film substrate has a rectangular shape, a square shape, a circular shape, a parallelogram shape, an elliptical shape, or a polygonal shape.

12. Apparatus according to any one of claims 1 to 11, wherein the reflector comprises an at least partially reflecting mirror.

13. Apparatus according to any one of claims 1 to 12, wherein the electrical winding comprises a toroidal coil arranged on the film substrate.

14. The apparatus of claim 13, wherein the annular coil is electrically connected to a power source via one or more arms attached to the platform.

15. The apparatus of any one of claims 1 to 14, wherein the one or more edges of the film substrate include a first edge, a second edge, a third edge, and a fourth edge.

16. The apparatus of claim 15, wherein one or more of the plurality of magnets are disposed proximate at least one of the first edge and the third edge.

17. An apparatus according to claim 16, wherein a first magnet among the one or more magnets is arranged so that the north pole of the first magnet is closer to the first edge than the south pole of the first magnet; and a second magnet among the one or more magnets is arranged so that the south pole of the second magnet is closer to the second edge than the north pole of the second magnet.

18. An apparatus according to any one of claims 15 to 17, wherein one or more of the plurality of magnets are disposed proximate each of the second edge and the fourth edge, wherein at least one of the second edge and the fourth edge is attached to an arm extending away from the film substrate.

19. An apparatus according to claim 18, wherein a first magnet among the one or more magnets is arranged so that the north pole of the first magnet is closer to the second edge than the south pole of the first magnet; and a second magnet among the one or more magnets is arranged so that the north pole of the second magnet is closer to the fourth edge than the south pole of the second magnet; and wherein the first magnet is aligned with the second magnet on one side of the axis.

20. An apparatus according to claim 19, wherein a third magnet among the one or more magnets is arranged so that the south pole of the third magnet is closer to the second edge than the north pole of the third magnet; and a fourth magnet among the one or more magnets is arranged so that the south pole of the fourth magnet is closer to the fourth edge than the north pole of the fourth magnet; and wherein the third magnet is aligned with the fourth magnet on the second side of the axis.

21. The apparatus according to any one of claims 1 to 20, wherein the reflector is made of silicon or glass material.

22. The apparatus according to any one of claims 1 to 21, further comprising: A rigid sheet metal is attached below the reflector and mounted on top of the coil.

23. The apparatus of claim 22, wherein the rigid sheet metal is made of a metallic material other than iron, nickel or cobalt.

24. The apparatus according to any one of claims 1 to 23, further comprising: A first arm is attached to the platform and extends away from the platform, wherein the first arm is aligned with the axis of the platform, and wherein the platform is configured to rotate or swing about the axis using the first arm.

25. The device according to claim 24, further comprising: A second arm is attached to the platform and extends away from the platform in a direction opposite to the first arm, wherein the second arm is aligned with the axis of the platform, and wherein the platform is configured to rotate or swing about the axis using the first arm and the second arm.

26. The apparatus of claim 25, wherein both the first arm and the second arm overlap the axis.

27. The apparatus of claim 26, wherein the first arm is attached to the platform at a substantially central location of a first edge of the platform, and the second arm is attached to the platform at a substantially central location of a second edge of the platform.

28. The apparatus of any one of claims 1 to 27, wherein one or more characteristics of the plurality of magnets and one or more characteristics of the electrical windings are configured based on one or more movement requirements of the reflector.

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