LIDAR system

Abstract

The LIDAR (Light Detection and Ranging) system includes a laser source and a polygon scanner. The laser source is configured to generate a first beam. The polygon scanner includes a frame and a plurality of mirrors coupled to the frame, each mirror being constructed of a glass material. At least one aspect relates to an autonomous vehicle control system. The autonomous vehicle control system includes a laser source, a polygon scanner, and one or more processors.

Description

Technical Field

[0001] Cross - reference to related applications This application claims the benefit of priority of and to U.S. Patent Application No. 17 / 592,286, filed Feb. 3, 2022. The entire disclosure of U.S. Patent Application No. 17 / 592,286 is incorporated herein by reference.

Background Art

[0002] Optical detection of distance using a laser, often referred to as a Mnemonic, and LIDAR (Light Detection and Ranging), often referred to as "laser RADAR", are used in various application fields including imaging and collision avoidance. LIDAR provides a finer scale range resolution with a smaller beam size than conventional microwave ranging systems such as RADAR (Radio Detection and Ranging).

Summary of the Invention

Means for Solving the Problems

[0003] At least one aspect relates to a Light Detection and Ranging (LIDAR) system. The LIDAR system includes a laser source and a polygon scanner configured to generate a beam. The polygon scanner includes a frame and a plurality of mirrors coupled to the frame, each mirror including a glass material.

[0004] At least one aspect relates to an autonomous vehicle control system. The autonomous vehicle control system includes a laser source, a polygon scanner, and one or more processors. The laser source is configured to generate a first beam. The polygon scanner includes a frame and a plurality of mirrors coupled to the frame, each mirror including a glass material, and the polygon scanner is configured to reflect the first beam into a second beam. The one or more processors are configured to determine at least one of a distance to an object or a speed of the object using a third beam received from at least one of a reflection or a scatter of the second beam by the object, and to control an operation of the autonomous vehicle in response to at least one of the distance or the speed.

[0005] At least one aspect relates to an autonomous vehicle. The autonomous vehicle includes a LIDAR system including a laser source configured to generate a first beam and a polygon scanner including a frame and a plurality of mirrors coupled to the frame, each mirror including a glass material. The autonomous vehicle includes a steering system, a braking system, and a vehicle controller including one or more processors, the one or more processors being configured to determine at least one of a distance to an object or a speed of the object using a third beam received from at least one of a reflection or a scatter of the second beam by the object, and to control an operation of at least one of the steering system and the braking system in response to at least one of the distance or the speed.

[0006] Those skilled in the art will understand that this summary is merely illustrative and is not intended to be limiting in any way. The features described herein can be used in conjunction with any other features, and any subset of these features can be used in combination according to various embodiments. Other aspects, features, and advantages of the apparatus and / or process described herein, which are defined only by the claims, will become apparent from the detailed description disclosed herein and will be considered in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0007] In the accompanying drawings, embodiments are shown in an illustrative rather than a limiting sense, and like reference numerals refer to like elements, where

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Best Mode for Carrying Out the Invention

[0019] A LIDAR system can generate an optical beam to which an object can reflect or scatter as a return beam corresponding to the transmitted beam, and can transmit the optical beam. The LIDAR system can receive the return beam and process the return beam or its characteristics to determine parameters regarding the object such as distance and velocity. The LIDAR system can apply various frequency or phase modulations to the transmitted beam, which can facilitate associating the return beam with the transmitted beam to determine parameters regarding the object.

[0020] The LIDAR system can include a laser source and a polygon scanner. The laser source is configured to generate a first beam. The polygon scanner includes a frame and a plurality of mirrors coupled to the frame, each mirror including a glass material. The mirror can reflect the first beam to output a second beam, which is scanned across a Field of View and can be reflected or scattered by an object as a third beam and used to determine distance, velocity, and Doppler information regarding the object to control the operation of an autonomous vehicle.

[0021] The systems and methods according to the present disclosure can embody a LIDAR system assembled such that a polygon scanner has multiple facets of polished glass mirrors attached to a frame, as compared to a polygon scanner formed by machining (e.g., a computer numerical control (CNC) process), e.g., manufactured from diamond-turned aluminum. By using polished glass mirrors for the facets, the surface of the facets can be made flatter and the roughness can be reduced, thereby improving reflectivity, reducing scattering, and / or enabling optical improvements such as a more special beam shape (e.g., a beam shape with a lesser degree of variation from an ideal Gaussian beam) that is preferable for autonomous vehicles. For example, by making the facets flatter and / or reducing the roughness, the possibility of reflection or scattering occurring within the surface of the facets themselves can be reduced (such reflections or scatterings can have a Doppler shift or add noise to signal processing). Also, the assembled polygon scanner can reduce weight and / or inertia compared to a polygon scanner manufactured from a solid metal block, improve the reliability of the motor that rotates the polygon scanner, and enable greater flexibility in the form factor of the facets (e.g., enabling larger facets or facets of various shapes, e.g., concave or convex facets). The assembled polygon scanner can be manufactured by a less complex and more scalable process. However, the advantages of the assembled polygon scanner described above are not limited to autonomous vehicles only. These can be advantageous for any type of vehicle equipped with a LIDAR sensor. 1. System environment for autonomous vehicles

[0022] Figure 1a is a block diagram showing an example of a system environment for an autonomous vehicle according to some embodiments. Figure 1a shows an exemplary autonomous vehicle 100 in which various technologies disclosed herein can be implemented. For example, vehicle 100 includes a prime mover 104 that receives power from an energy source 106, a powertrain 102 that can supply power to a drivetrain 108, and a control system 110 that includes a direction control 112, a powertrain control 114, and a brake control 116. Vehicle 100 can transport people and / or cargo and can be implemented in various types including vehicles that can travel in various environments. The aforementioned components 102-116 can vary widely based on the type of vehicle in which they are used, such as a wheeled land vehicle like a passenger car, van, truck, and bus. Prime mover 104 can include one or more electric motors and / or internal combustion engines (among other things). Energy source 106 can include, for example, a fuel system (e.g., providing gasoline, diesel, hydrogen, etc.), a battery system, a solar panel or other renewable energy source, and / or a fuel cell system. Drivetrain 108 includes a transmission suitable for converting the output of prime mover 104 into vehicle motion and / or any other mechanical drive component, one or more brakes configured to controllably stop or decelerate vehicle 100 together with wheels and / or tires, and a direction or steering component suitable for controlling the trajectory of vehicle 100 (e.g., a rack and pinion steering linkage that allows one or more wheels of vehicle 100 to pivot generally about a vertical axis to change the angle of the rotation plane of the wheel with respect to the longitudinal axis of the vehicle). In some embodiments, a combination of a powertrain and an energy source can be used (e.g., in the case of an electric / gas hybrid vehicle), and in some embodiments, multiple electric motors (e.g., dedicated to individual wheels or axles) can be used as the prime mover.

[0023] The direction control 112 may include one or more actuators and / or sensors for controlling and receiving feedback from the direction or steering components to enable the vehicle 100 to follow a desired trajectory. The power train control 114 is configured to control the speed and / or direction of the vehicle 100 by controlling the output of the power train 102, for example, by controlling the output power of the prime mover 104 and controlling the gears of the transmission of the drive train 108. The brake control 116 may be configured to control one or more brakes that decelerate or stop the vehicle 100, such as disk or drum brakes coupled to the wheels of the vehicle.

[0024] Other vehicle types, including but not limited to off-road vehicles, all-terrain vehicles or track-type vehicles, construction equipment, etc., can use various power trains, drive trains, energy sources, direction controls, power train controls and brake controls. Further, in some embodiments, some components may be coupled. For example, the direction control of the vehicle is mainly processed by changing the output of one or more prime movers.

[0025] Various levels of autonomous control for the vehicle 100 are implemented in the vehicle control system 120, which may include one or more processors 122 and one or more memories 124, and each processor 122 is configured to execute program code instructions 126 stored in the memory 124. The processor may include, for example, graphics processing units (GPUs) and / or central processing units (CPUs).

[0026] Sensor 130 may include various sensors suitable for collecting information from the vehicle's surrounding environment for use in controlling the operation of the vehicle. For example, sensor 130 may include a RADAR sensor 134, a LIDAR sensor 136, a 3D positioning sensor 138, such as an accelerometer, a gyroscope, a magnetometer, or a satellite navigation system such as GPS (Global Positioning System), GLONASS (Globalnaya Navigazionnaya Sputnikovaya Sistema, or Global Navigation Satellite System), BeiDou Navigation Satellite System (BDS), Galileo, Compass, etc. The 3D positioning sensor 138 can be used to determine the vehicle's position on the earth using satellite signals. Sensor 130 may include a camera 140 and / or an inertial measurement unit (IMU) 142. The camera 140 can be a monographic or stereographic camera and can record still images and / or videos. The IMU 142 may include multiple gyroscopes and accelerometers that can detect the linear and rotational motion of the vehicle in three directions. One or more encoders 144, such as wheel encoders, can be used to monitor the rotation of one or more wheels of the vehicle 100. Each sensor 130 can output sensor data at various data rates that are different from the data rates of other sensors 130.

[0027] The output of sensor 130 can be provided to a series of control subsystems 150 including a localization subsystem 152, a perception subsystem 154, a planning subsystem 156, and a control subsystem 158. The localization subsystem 152 is mainly responsible for accurately determining the position and orientation (sometimes also called "pose" or "pose estimation") of the vehicle 100 within the surrounding environment and generally within a partial reference frame. The perception subsystem 154 is mainly responsible for detecting, tracking, and / or identifying objects within the surrounding environment of the vehicle 100. Machine learning models according to some embodiments can be utilized to track objects. The planning subsystem 156 is mainly responsible for planning the trajectory or movement path of the vehicle 100 over a given time frame with respect to not only stationary and moving objects in the environment but also a desired destination. The position of the autonomous vehicle can be compared with the position of additional vehicles in the same environment as part of the labeled autonomous vehicle data generation. The perception subsystem 154 can perform functions such as detecting, tracking, determining, and / or identifying objects within the environment surrounding the vehicle 100. Machine learning models according to some embodiments can be utilized to track objects. The planning subsystem 156 can perform functions such as planning the trajectory of the vehicle 100 over a given time frame with respect to not only the desired destination but also stationary and moving objects in the environment. Machine learning models according to some embodiments can be utilized to plan the vehicle trajectory. The control subsystem 158 can perform functions such as generating appropriate control signals for controlling various control devices of the vehicle control system 120 to embody the planned trajectory of the vehicle 100. Machine learning models can be utilized to generate one or more signals for controlling the autonomous vehicle to embody the planned trajectory.

[0028] Multiple sensors of the type shown in FIG. 1a can be used to provide redundancy and / or cover various areas around the vehicle, and other types of sensors can be used. Various types and / or combinations of control subsystems can be used. Some or all of the functions of subsystems 152-158 can reside in one or more memories 124 and be embodied by program code instructions 126 executed by one or more processors 122, and these subsystems 152-158 can, in some cases, be embodied using the same processor and / or memory. The subsystems can be embodied using at least in part various dedicated circuit logics, various processors, various field programmable gate arrays (FPGAs), various application specific integrated circuits (ASICs), various real-time controllers, etc., and as described above, many subsystems can use circuits, processors, sensors, and / or other components. Also, the various components of vehicle control system 120 can be networked in various ways.

[0029] In some embodiments, vehicle 100 can further include a secondary vehicle control system (not shown) that can be used as a redundant or backup control system for vehicle 100. In some embodiments, the secondary vehicle control system can fully operate the autonomous vehicle 100 if an adverse event occurs in vehicle control system 120, but in other embodiments, the secondary vehicle control system can have only limited functionality such as performing a controlled stop of vehicle 100 in response to an adverse event detected by the primary vehicle control system 120. In still other embodiments, the secondary vehicle control system may be omitted.

[0030] The various components shown in FIG. 1 can be implemented using a variety of architectures including various combinations such as software, hardware, circuit logic, sensors, and networks. Each processor can be implemented, for example, as a microprocessor, and each memory can include not only a random access memory (RAM) device including a main memory, but also any auxiliary level of memory such as cache memory, non-volatile or backup memory (e.g., programmable or flash memory), read-only memory, and the like. Also, each memory can be considered to include not only a memory storage device physically located elsewhere in vehicle 100, such as any cache memory within the processor, but also any storage capacity used as virtual memory, such as stored in a mass storage device or other computer controller. One or more of the processors shown in FIG. 1a or a completely different processor can be used to implement additional functions within vehicle 100 other than for autonomous control purposes, such as controlling an entertainment system, operating doors, lighting, convenience functions, and the like.

[0031] Also, for additional storage, vehicle 100 can include one or more mass storage devices such as removable disk drives, hard disk drives, direct access storage devices (DASD), optical drives (e.g., CD drives, DVD drives, etc.), solid state storage drives (SSD), network attached storage, storage area networks, and / or tape drives, and the like.

[0032] Furthermore, vehicle 100 can include a user interface 164 such as one or more displays, touchscreens, voice and / or gesture interfaces, buttons, and tactile control devices to enable vehicle 100 to receive a number of inputs from a user or operator and generate outputs therefor. Otherwise, user input can be received via another computer or electronic device such as an app or web interface of a mobile device.

[0033] Furthermore, vehicle 100 can communicate with one or more networks 170 (e.g., a local area network (LAN), a wide area network (WAN), a wireless network, and / or the Internet) through one or more network interfaces suitable for such communication, such as network interface 162, enabling information communication with other computers and electronic devices, including central services such as cloud services. As a result, vehicle 100 can receive environments and other data that can be used for autonomous control. Data collected by one or more sensors 130 can be uploaded to computing system 172 via network 170 for additional processing. In some embodiments, a timestamp can be added to each instance of vehicle data before uploading.

[0034] Not only each processor shown in FIG. 1a, but also various additional controllers and subsystems disclosed herein generally operate under the control of an operating system and perform or rely on various computer software applications, components, programs, objects, modules, data structures, etc., as will be described in detail below. Also, various applications, components, programs, objects, modules, etc. can be performed by one or more processors of other computers connected to vehicle 100 via network 170, for example, in a distributed, cloud-based, or client-server computing environment, and the processing required to implement the functions of the computer program can be allocated to multiple computers and / or services via the network.

[0035] Generally, the routines performed to implement the various embodiments described herein may be embodied as part of an operating system or as a particular application, component, program, object, module, or sequence of instructions, or as a subset thereof, and are referred to herein as "program code." Program code is generally composed of one or more instructions that reside at various times in various memories and storage devices and, when read and executed by one or more processors, perform the steps necessary to execute the steps or elements that implement the various aspects of the present disclosure. Also, while the embodiments are described in the context of fully functional computers and systems, it should be understood that the various embodiments described herein can be distributed as a variety of forms of program products and that such embodiments can be implemented regardless of the particular type of computer-readable media used to actually effect the distribution.

[0036] Examples of computer-readable media include tangible non-transitory media such as volatile and non-volatile memory devices, floppy disks and other removable disks, solid state drives, hard disk drives, magnetic tape, and optical disks (e.g., CD-ROM, DVD, etc.).

[0037] Moreover, the various program codes described below can be identified based on the applications implemented in specific embodiments. However, any of the following specific program nomenclatures are used merely for convenience, and thus, the present disclosure should not be limited to use only in any specific application identified and / or implied by such nomenclature. Further, the ways in which a computer program can be composed of routines, procedures, methods, modules, objects, etc. are generally endless, and when considering the various ways in which program functions are allocated to various software layers resident within ordinary computers (e.g., operating systems, libraries, APIs, applications, applets, etc.), the present disclosure is not limited to the specific structures and allocations of the program functions described herein. 2. LIDAR for automotive applications

[0038] The track may include a LIDAR system (e.g., among others described herein, the vehicle control system 120 of FIG. 1a and the LIDAR system 200 of FIG. 2). In some embodiments, the LIDAR system can encode an optical signal using frequency modulation and scatter the encoded optical signal into free space using an optical device. By detecting the frequency difference between the encoded optical signal and the return signal reflected back from an object, a frequency modulation (FM) LIDAR system can determine the position of the object and / or accurately measure the speed of the object using the Doppler effect. In some embodiments, the FM LIDAR system can use continuous wave (referred to as "FMCW LIDAR") or quasi-continuous wave (referred to as "FMQW LIDAR"). In some embodiments, the LIDAR system can encode an optical signal using phase modulation (PM) and scatter the encoded optical signal into free space using an Optics.

[0039] In some cases, an object (e.g., a pedestrian wearing dark clothing) may have a low reflectivity in that only a small amount of the light hitting the object (e.g., 10% or less) is reflected back to the sensor (e.g., sensor 130 in FIG. 1a) of the FM or PM LIDAR system. In other cases, an object (e.g., a shiny road sign) may have a high reflectivity (e.g., 10% or more) in that a large amount of the light hitting the object is reflected back to the sensor of the FM LIDAR system.

[0040] Regardless of the reflectivity of the object, the FM LIDAR system can detect (e.g., classify, recognize, discover, etc.) the object at a greater distance (e.g., twice) than a conventional LIDAR system. For example, the FM LIDAR system can detect a low-reflectivity object beyond 300 meters and a high-reflectivity object beyond 400 meters.

[0041] To achieve such an improvement in detection capabilities, the FM LIDAR system can use sensors (e.g., sensor 130 in FIG. 1a). In some embodiments, these sensors may be sensitive to single photons, which means that the sensors can detect the minimum amount of light possible. In some applications, the FM LIDAR system can use infrared wavelengths (e.g., 950 nm, 1550 nm, etc.), but is not limited to the infrared wavelength range (e.g., near infrared: 800 nm to 1500 nm, mid-infrared: 1500 nm to 5600 nm, and far-infrared: 5600 nm to 1000000 nm). By operating the FM or PM LIDAR system at infrared wavelengths, the FM or PM LIDAR system can broadcast a stronger light pulse or light beam than a conventional LIDAR system.

[0042] That is, by detecting objects at a greater distance, the FM LIDAR system may have more time to react to unforeseen obstacles. In fact, even a few milliseconds of extra time can improve response time and comfort, especially in the case of large vehicles (e.g., commercial truck transports) traveling at highway speeds.

[0043] The FM LIDAR system can immediately provide the exact velocity for each data point. In some embodiments, velocity measurement is achieved by utilizing the Doppler effect that shifts the frequency of the light received from the object based on at least one of the velocity in the radial direction (e.g., the direction vector between the detected object and the sensor) or the frequency of the laser signal. For example, for velocities occurring in road situations where the velocity is less than 100 m / s, this shift at a wavelength of 1550 nanometers (nm) corresponds to a frequency shift of less than 130 MHz. This frequency shift is so small that it is difficult to directly detect in the optical domain. However, by using coherent detection in an FMCW, PMCW, or FMQW LIDAR system, the signal can be converted to the RF domain and the frequency shift can be calculated using various signal processing techniques. This enables an autonomous vehicle control system to process the received data more quickly.

[0044] Also, instantaneous velocity calculation becomes easier when the FM LIDAR system is detecting distant or sparse data points as objects and / or tracking how these objects are moving over time. For example, an FM LIDAR sensor (e.g., sensor 130 of FIG. 1a) may only receive a few returns (e.g., hits) for an object that is 300 m away, but if these returns provide a velocity value of interest (e.g., moving towards the vehicle at a speed >70 mph), the FM LIDAR system and / or the autonomous vehicle control system can determine individual weights for the probabilities associated with the object.

[0045] Faster identification and / or tracking of the FM LIDAR system provides more time for the autonomous vehicle control system to maneuver the vehicle. By better understanding how fast an object is moving, the autonomous vehicle control system can also plan more appropriate responses.

[0046] The FM LIDAR system may have less noise compared to conventional LIDAR systems. That is, conventional LIDAR systems designed to have more light sensitivity generally do not operate correctly in bright sunlight. Such systems tend to suffer from crosstalk (e.g., when sensors are cross-wired by each other's light pulses or light beams) and self-interference (e.g., when sensors are cross-wired by previous light pulses or light beams). To overcome this drawback, vehicles using conventional LIDAR systems often require additional hardware, complex software, and / or more computing power to manage these "noises".

[0047] In contrast, the FM LIDAR system is specially designed so that each sensor responds only to its own light characteristics (e.g., light beam, light wave, light pulse), and thus does not experience this kind of problem. If the returned light does not match the timing, frequency, and / or wavelength of the light initially transmitted, the FM sensor can filter (e.g., remove, ignore, etc.) the data point. This allows the FM LIDAR system to produce (e.g., generate, derive, etc.) more accurate data with fewer hardware or software requirements, enabling smoother operation.

[0048] The FM LIDAR system may be easier to expand than conventional LIDAR systems. As more autonomous vehicles (e.g., cars, commercial trucks, etc.) appear on the road, vehicles driven by the FM LIDAR system will not need to face interference problems due to sensor crosstalk. Also, the FM LIDAR system uses less optical peak power than conventional LIDAR sensors. As a result, some or all of the optical components for FM LIDAR can be produced on a single chip, which provides unique advantages as discussed herein. 2.1 Commercial Truck Transportation

[0049] FIG. 1b is a block diagram showing an example of a system environment for an autonomous commercial truck according to some embodiments. Environment 100B includes a commercial truck 102B for carrying cargo 106B. In some embodiments, commercial truck 102B can include vehicles configured for long-haul cargo transportation, regional cargo transportation, intermodal cargo transportation (i.e., used as one of several transportation modes for a vehicle on a road infrastructure to transport cargo) and / or any other road infrastructure cargo transportation applications. In some embodiments, commercial truck 102B can be a flatbed truck, a refrigerated truck (e.g., a reefer truck), a vented van (e.g., a dry van), a moving truck, etc. In some embodiments, cargo 106B can be goods and / or products. In some embodiments, commercial truck 102B can include a trailer for carrying cargo 106B such as a flatbed trailer, a lowboy trailer, a step deck trailer, an expandable flatbed trailer, a sidekit trailer, etc.

[0050] Environment 100B includes an object 110B (shown as another vehicle in FIG. 1b) within a distance range of 30 meters or less from the truck.

[0051] The commercial truck 102B may include a LIDAR system 104B (e.g., an FM LIDAR system, the vehicle control system 120 of FIG. 1a or the LIDAR system 200 of FIG. 2a) for determining the distance to an object 110B and / or measuring the speed of the object 110B. FIG. 1b shows one LIDAR system 104B mounted on the front of the commercial truck 102B, but the number of LIDAR systems of the commercial truck and the mounting area of the LIDAR system are not limited to a specific number and a specific area. The commercial truck 102B can include any number of LIDAR systems 104B (or its components such as sensors, modulators, coherent signal generators, etc.) mounted in any area (e.g., front, rear, side, upper, lower, bottom, and / or underneath), facilitating the detection of any object in free space with respect to the commercial truck 102B.

[0052] As shown, the LIDAR system 104B of the environment 100B can be configured to detect objects (e.g., other vehicles, bicycles, trees, road signs, potholes, etc.) at a short distance (e.g., 30 meters or less) from the commercial truck 102B.

[0053] FIG. 1c is a block diagram showing an example of a system environment for an autonomous commercial truck according to some embodiments. The environment 100C includes the same components (e.g., the commercial truck 102B, the cargo 106B, the LIDAR system 104B, etc.) included in the environment 100B.

[0054] The environment 100C includes an object 110C (shown as another vehicle in FIG. 1c) within a distance range of (i) 30 meters or more and (ii) 150 meters or less from the commercial truck 102B. As shown, the LIDAR system 104B of the environment 100C can be configured to detect objects (e.g., other vehicles, bicycles, trees, road signs, potholes, etc.) at a certain distance (e.g., 100 meters) away from the commercial truck 102B.

[0055] FIG. 1d is a block diagram illustrating an example of a system environment for an autonomous commercial truck according to some embodiments. Environment 100D includes the same components (e.g., commercial truck 102B, cargo 106B, LIDAR system 104B, etc.) included in environment 100B.

[0056] Environment 100D includes an object 110D (shown as another vehicle in FIG. 1d) within a distance range of 150 meters or more away from commercial truck 102B. As shown, the LIDAR system 104B of environment 100D can be configured to detect objects (e.g., other vehicles, bicycles, trees, road signs, potholes, etc.) at a certain distance (e.g., 300 meters) away from commercial truck 102B.

[0057] In the commercial truck transportation application field, it is important to effectively detect objects in all ranges due to the increased weight and thus longer stopping distance. FM LIDAR systems (e.g., FMCW and / or FMQW systems) or PM LIDAR systems are optimal for commercial truck transportation applications due to the aforementioned advantages. Ultimately, a commercial truck equipped with such a system can improve its ability to safely move both people and goods over short or long distances. In various embodiments, these FM or PM LIDAR systems can be used in semi-autonomous application fields where a driver is on board the commercial truck and some functions of the commercial truck operate autonomously using the FM or PM LIDAR system, or in fully autonomous application fields where the commercial truck operates alone or in combination with other vehicle systems solely by the FM or LIDAR system. 3. LIDAR system

[0058] FIG. 2 shows an example of a LIDAR system 200. The LIDAR system 200 can be used to determine parameters regarding an object such as distance and velocity, and output the parameters to a remote system. For example, the LIDAR system 200 can output the parameters for use by a vehicle controller (e.g., vehicle controller 298) that can control the operation of a vehicle in response to the received parameters or by a display that can provide a representation of the parameters. The LIDAR system 200 can be a coherent detection system. The LIDAR system 200 can be used to embody various features and components of the systems described with reference to FIGS. 1a - 1d. The LIDAR system 200 can include components for performing various detection approaches such as operating as an amplitude modulated LIDAR system or a coherent LIDAR system. The LIDAR system 200 can be used to perform time of flight distance determination. In some embodiments, various components of the LIDAR system 200, such as the laser source 204 and the modulator 214, or combinations of components, can be within the same housing, provided on the same circuit board or other electronic component, or otherwise integrated. In some embodiments, various components of the LIDAR system 200, or combinations of components, can be provided as other components such as components that generate and / or receive optical signals such as optical beams using optical coupling (e.g., optical fiber), or components that generate and receive electrical (e.g., data) signals using wired or wireless electronic connections.

[0059] The LIDAR system 200 can include a laser source 204 that generates and emits a beam 206, such as a carrier light beam. The splitter 208 can split the beam 206 into a beam 210 and a reference beam 212 (e.g., reference signal). In some embodiments, any suitable optical, electronic, or optoelectronic elements can be used to provide the beam 210 and the reference beam 212 from the laser 204 to other elements.

[0060] The modulator 214 can modulate one or more attributes of the input beam 210 to generate a beam 216 (e.g., a target beam). In some embodiments, the modulator 214 can modulate the frequency of the input beam 210 (e.g., the optical frequency corresponding to the optical wavelength, where c = λν, where c is the speed of light, λ is the wavelength, and ν is the frequency). For example, the modulator 214 can linearly modulate the frequency of the input beam 210 such that the frequency of the beam 216 increases or decreases linearly over time. As another example, the modulator 214 can non-linearly (e.g., exponentially) modulate the frequency of the input beam 210. In some embodiments, the modulator 214 can modulate the phase of the input beam 210 to generate the beam 216. However, the modulation techniques are not limited to frequency modulation and phase modulation. Any suitable modulation technique can be used to modulate one or more attributes of the beam. Returning to FIG. 2, the modulator 214 can modulate the beam 210 after the beam 206 is split by the splitter 208 so that the reference beam 212 is not modulated, or the modulator 214 can modulate the beam 206 and provide the modulated beam to the splitter 208, thereby splitting it into a target beam and a reference beam via the splitter 208.

[0061] The beam 216 used to output the transmitted signal can have most of the energy of the beam 206 output by the laser source 204, while the reference beam 212 can have relatively little energy but can have sufficient energy to enable mixing with the return beam 248 (e.g., the returned light) scattered from the object. The reference beam 212 can be used as a Local Oscillator (LO) signal. The reference beam 212 can pass through the reference path and be provided to the mixer 260. The amplifier 220 can amplify the beam 216 to output a beam 222, and the collimator 224 can collimate it to output a beam 226.

[0062] As shown in FIG. 2, the circulator 228 can be positioned between the collimator 224 and the optical system 232 to receive the beam 226 and output the beam 230 to the optical system 232. The circulator 228 can be positioned between the laser source 204 and the collimator 224. The circulator 228 can receive the return beam 248 from the optical system 232 and provide the return beam 248 to the mixer 260. The optical system 232 can be a scanning optics, such as one or more polygon reflector deflectors, and can adjust the angle of the received beam with respect to the beam output based on the outer surface of the optical system (e.g., facet) for the received beam, or the direction of a solid-state component (e.g., phase array, electro-optic crystal) configured to modify the direction of the received light.

[0063] The optical system 232 can define a field of view 244 corresponding to the angle scanned (e.g., swept) by the beam 242 (e.g., the transmitted beam). For example, the beam 242 can be scanned in a specific plane, such as an azimuth plane or an altitude plane (e.g., with respect to an object to which the LIDAR system 200, such as an autonomous vehicle, is coupled). The optical system 232 can be oriented such that the field of view 244 sweeps the azimuth plane with respect to the optical system 232.

[0064] At least one motor 240 can be coupled to the optical system 232 to control at least one of the position or orientation of the optical system 232 with respect to the beam 230. For example, if the optical system 232 includes a reflector or deflector, the motor 240 can rotate the optical system 232 such that the surface of the optical system 232 where the beam 230 is received changes in angle or direction with respect to the beam 230, and can change the angle or direction when the beam 242 is output from the optical system 232.

[0065] The beam 242 can be output from the optical system 232 and can be reflected or scattered by an object (not shown) as a return beam 248 (e.g., a return signal). The return beam 248 can be received in a reception path that can include a circulator 228 and can be provided to a mixer 260.

[0066] The mixer 260 can be an optical hybrid such as a 90-degree optical hybrid. The mixer 260 can receive the reference beam 212 and the return beam 248 and mix the reference beam 212 and the return beam 248 to output a signal 264 that responds to the reference beam 212 and the return beam 248. The signal 264 can include an in-phase (I) component 268 and a quadrature (Q) component 272.

[0067] The LIDAR system 200 can include a receiver 276 that receives the signal 264 from the mixer 260. The receiver 276 can generate a signal 280 that responds to the signal 264, which can be an electronic (e.g., radio frequency) signal. The receiver 276 can include one or more photodetectors that output the signal 280 in response to the signal 264.

[0068] The LIDAR system 200 may include a processing system 290, which can be implemented using the features of the vehicle control system 120 described with reference to FIG. 1a. The processing system 290 can process data received in relation to a return beam 248 such as a signal 280 and determine parameters regarding an object such as distance and speed. The processing system 290 may include a scanner controller 292 that can provide a scan signal to control the operation of the optical system 232 to rotate the optical system 232 so that the motor 240 achieves a target scan pattern such as a sawtooth scan pattern or a step function scan pattern. The processing system 290 may include a Doppler compensator 294 that can determine the sign and magnitude of the Doppler shift associated with the processing of the return beam 248, as well as a correction range based thereon, along with other corrections. The processing system 290 may include a modulator controller 296 that can transmit one or more electrical signals to drive the modulator 214.

[0069] The processing system 290 may include or be communicatively coupled to a vehicle controller 298 to control the operation of the vehicle in which the LIDAR system 200 is installed (e.g., to provide full or semi-autonomous control of the vehicle). For example, the vehicle controller 298 can be implemented by at least one of the LIDAR system 200 or the control circuitry of the vehicle. The vehicle controller 298 can control the operation of the vehicle in response to at least one of the distance to an object or the speed of the object determined by the processing system 290. For example, the vehicle controller 298 can transmit a control signal to at least one of the steering system or the braking system of the vehicle to control at least one of the speed or direction of the vehicle.

[0070] Figures 3 to 5 show an embodiment of the optical system 300 for a scanner. The scanner includes an optical system 232 and a motor 240 as described with reference to FIG. 2. For example, the LIDAR system 200 may include one or more scanners for transmitting a beam to an object and / or receiving a beam from the object to determine information such as distance, velocity, or Doppler effect related to the object.

[0071] In some embodiments, the optical system 300 can be an assembled polygon including a plurality of mirrors 304 coupled to a frame 308. Instead of machining a metal block to form the scanner, by assembling the optical system 300 from separate components, the optical system 300 can be manufactured to have improved optical and mechanical performance including flexibility in mirror form factor, low weight / inertia for a given mirror size, optical surface quality (e.g., reduction in roughness), low volume cost, and robustness to stresses such as heat, shock, and vibration stress. For example, by forming the optical system 300 with an assembled device, the scanner can have a mass and inertia about half that of a solid metal scanner with a similar or identical mirror size with respect to axis 402 (e.g., a mass of 0.09 kg and an axis 402 inertia of 5.2e-5 kg m 2 of axis 402 inertia, 0.2 kg and 1.05e-5 kg m 2 inertia when compared to a solid metal scanner).

[0072] The mirror 304 can be a facet and can have an outer surface 312 from which the received beam is reflected and output after being received by the mirror 304. The mirror 304 can be reflected for light used in LIDAR applications (e.g., light received from the laser 204 through one or more components as shown in FIG. 2 between the laser source 204 and the optical system 232). For example, the mirror 304 can include light of about 1550 nm and can be reflected for light having a wavelength between 1100 nm and 1800 nm.

[0073] The optical system 300 can include various numbers of mirrors 304. For example, the optical system 300 can include from 3 to 12 mirrors 304. The mirrors 304 can be arranged around the periphery 306 of the frame 308 and can define, for example, a polygonal shape. Each mirror 304 can have the same shape as at least one other mirror 304, such as a rectangular shape with the same length and width, a circular or elliptical shape with the same perimeter, a convex or concave polygonal shape with the same number and length of sides, and various other similar or identical shapes.

[0074] The mirrors 304 can be sized to extend outward from the frame 308. For example, the plane on which the surface 414 of the frame 308 lies can intersect at least one mirror 304 inward from the outer edge 310 of at least one mirror 304. For example, the mirrors 304 can extend beyond the extent of the frame 308 defined by the surface 414. The mirrors 304 can extend further in the vertical direction of the frame 308 in a reference frame where at least one of the axes 402 is parallel to gravity or the surface 414 is parallel to the ground. Thus, the overall form factor size can be reduced because the various components of the LIDAR system 200 can be arranged more flexibly with respect to each other and with respect to the optical system 300.

[0075] The mirrors 304 can include a glass material. For example, the mirrors 304 can include optical glass such as crown glass or flint glass. For example, the mirrors 304 can include K9 glass or BK7 glass, which can have improved thermal performance. As another example, the mirrors 304 can include fused silica glass, which can operate effectively under ultraviolet and near-infrared (NIR) light conditions with a low coefficient of thermal expansion. The mirrors 304 can be formed by cutting from a larger glass panel, which enables more extensible manufacturing of the mirrors 304.

[0076] In some embodiments, a mirror (e.g., surface 312) can be polished. Since glass is used for the mirror 304 (e.g., instead of metal materials such as CNC machining and diamond machining aluminum), the mirror 304 can be polished to a flatter and less rough state, and as a result, by reducing the scattering of light incident by the surface 312 (and then, after being reflected from the back of the mirror 304, reducing the scattering again and outputting from the surface 312), it can have improved optical properties. For example, in an example of a scattering test of the glass mirror 304 compared with diamond machined aluminum (each coated with unprotected gold), it was found that the polished glass of the mirror 304 has a relative scattering of 0.80 dB, while the metal (diamond machined aluminum) has a relative scattering of 6.14 dB. Therefore, the glass mirror 304 can reduce the possibility of light ray scattering within the structure defining the roughness of the surface 312, which can solve problems such as the Doppler component that contributes to the beam signal by scattering. As a result, the signal processing required to remove the Doppler component can be reduced or removed, so the computational requirements of the signal processing can be reduced. In some embodiments, the mirror 304 can be coated. For example, gold (e.g., unprotected gold) can be used as the coating material. However, the coating material is not limited to gold. Instead, a suitable reflective material can be used as the coating material.

[0077] As shown in FIGS. 3 to 5, the mirror 304 may have a rectangular shape. The mirror 304 may have various shapes or form factors including concave or convex shapes depending not only on the shape of the glass panel on which the mirror 304 is made, but also on whether the mirror 304 is cut from the glass panel or extracted by other means. For example, since the glass panel can be curved, the mirror 304 can be formed to be curved (e.g., concave or convex), and the shape of the mirror 304 extracted from the glass panel can also be controlled to select the shape of the mirror 304 such as providing the mirror 304 with a rounded edge 310. Therefore, the mirror 304 can be fabricated to direct beams received at various directions or angles depending on the shape of the mirror 304. The mirror 304 can be made to have a relatively large surface area of the surface 312 compared to using a high-density metal for the mirror 304 without increasing the weight / inertia of the mirror 304 (or while maintaining the size while reducing the weight / inertia). Also, by forming the mirror 304 using glass, the shape or form factor of the mirror 304 can be more easily selected and implemented according to a specific application compared to a solid metal scanner.

[0078] In some embodiments, each mirror 304 may extend from a first edge 316 to a second edge 320 and may be arranged such that there is a gap 324 between each edge 316, 320 of adjacent mirrors 304. The gap 324 allows for expansion or other movement or shape changes of the mirror 304 due to thermal or vibration effects. The edges 316, 320 can be angled such that the size of the gap 324 decreases in a direction away from the axis 402 (while some gap 324 remains even where the edges 316, 320 contact the surface 312). In some other embodiments, the mirrors 304 may be arranged without a gap between each edge 320 of adjacent mirrors 304.

[0079] The frame 308 can be made of a metallic material such as formed as a metal block. For example, the frame 308 can be made of aluminum. Using aluminum for the frame 308 can make the frame 308 relatively lightweight and facilitate manufacturing. The frame 308 or a part thereof can be made from various materials such as plastics or composite materials that have sufficient rigidity or other material or structural properties over the operating temperature of the LIDAR system, enabling efficient force transmission from the frame 308 to the mirror 304.

[0080] Each mirror 304 can be coupled to a respective coupling surface 404 of the frame 308. The coupling surface 404 can be located on or defined on the periphery 306 of the frame 308. For example, the frame 308 can include a wall 408 (e.g., a peripheral wall) that is oriented to cross the axis 402 of the frame 308. The coupling surface 404 can be defined on the wall 408. As shown in FIG. 3, the coupling surface 404 can extend over each portion of the wall 408, with a portion 412 of the wall 408 existing between the coupling surfaces 404 on both sides of the coupling surface 404. The portion 412 can be spaced from the inner surface 416 of the mirror 304 (compared to a solid-shaped scanner where there is no space or gap between the reflective surface and the inner portion of the scanner), and the spacing can pass through the wall 408 and be defined in a plane perpendicular to the axis 402. The coupling surface 404 can be flat, but the portion 412 can be formed in a curved or other shape so as to extend inwardly from the inner surface 416. The central portion of the inner surface 416 can be coupled to the coupling surface 404 (e.g., the coupling surface 404 can be located at the center of the inner surface 416), which can minimize the radial effect on the mirror 304 or other components during thermal expansion and contraction due to temperature changes.

[0081] An adhesive (e.g., a bonding material) can be provided on the bonding surface 404 to attach the mirror 304 to the bonding surface 404 (e.g., disposed at the inner surface 416 and / or the central portion of the bonding surface 404), which allows for symmetric thermal expansion (e.g., relatively low thermally generated expansion stress). For example, an epoxy such as dispensing epoxy can be used to attach the mirror 304 to the bonding surface 404. At least one of the material properties of the adhesive and the surface area of the bonding surface 404 can be selected such that the adhesion force between the bonding surface 404 and the mirror 304 is greater than the apparent (e.g., centrifugal) force that can push the mirror 304 out of the bonding surface 404 during the operation of the optical system 300 by the rotation of the optical system 300 (e.g., the rotation of the scanner of the optical system 300) about the axis 402. For example, the adhesion force can be at least a threshold value greater than the centrifugal force at the maximum expected rotation speed of the scanner. The adhesive can be selected to be similar to the mirror 304 or have a substantially the same coefficient of thermal expansion, which can improve the performance of the optical system 300 with respect to thermal expansion or contraction.

[0082] The frame 308 can include a shaft receiver 420 inwardly from the wall 408. The shaft receiver 420 can be a channel or other opening for allowing a shaft (e.g., a shaft or axle coupled to the motor 240 described with reference to FIG. 2) to be coupled to the frame 308, and the motor 240 rotates the shaft to rotate the frame 308 about the axis 402. The motor 240 is coupled to the frame 308 using various shafts, gears, or other couplings and can rotate the frame 308 about the axis 402. The axis 402 can be defined as at least one of being extended through the shaft receiver 420, or coinciding with the rotation axis of the motor 240, or coinciding with the rotation axis of the shaft (e.g., the shaft can be rotated about an axis offset from the motor 240 by the use of gears or other assemblies).

[0083] Figures 6 to 8 show diagrams studying the performance of mirror 304 during operation and under various environmental conditions such as thermal, shock, and vibration conditions. As shown in Figures 6 to 8, the optical system 300 can be designed as described herein to have a low weight / inertia so as to minimize the impact on the quality of the optical surface over a wide temperature range and to have the advantage of robustness in shock / vibration (e.g., due to the operation of motor 240).

[0084] Figure 6 shows a chart 600 regarding the distortion of mirror 304 with respect to the thermal load under the thermal stress expected for the operation of a LIDAR system for automotive applications. For example, at least one mirror 304 can have a distortion of about 200 nm or less from the plane of the mirror 304, e.g., a distortion between 0 nm and about 200 nm. As shown in Figure 6, it has been found that mirror 304 has a distortion (e.g., movement from the plane of surface 312) in the range from 101 nanometers at a temperature of minus 20 degrees Celsius to 67 nanometers at a temperature of 50 degrees Celsius. The coupling located centrally between mirror 304 and coupling surface 404 can enable such distortion performance in order to reduce or minimize various characteristics of optical system 300 described herein, such as the stress and distortion affecting the bond.

[0085] Figure 7 shows a chart 700 of the bond patch peel load. The bond patch peel load can correspond to the vertical load caused by the impact stress on the optical system 300, such as the impact transmitted from the vehicle to the optical system 300 (e.g., via motor 240). The optical system 300 can be configured as described herein such that, based on the weight of mirror 304 and the bond between mirror 304 and frame 308, mirror 304 can withstand a bond peel stress of 0.16 MPa (which can correspond to a stress of 16 N / m considering the size of mirror 304) corresponding to a vertical load of, for example, 50G.

[0086] Figure 8 shows a chart 800 of the angular displacement of mirror 304 with respect to the vibration condition. As shown in Figure 8, 3G RMSIn response to vibrations of (root mean square acceleration related to random vibrations), mirror 304 can have a rigid body tilt of 1.3 nm or an angular displacement of 37.1e-9 radians at a vibration of 667 Hz.

[0087] As described above, some exemplary embodiments have been described. It is clear that the foregoing embodiments are exemplary and are not limited to those presented by way of example. In particular, although many of the examples presented herein include specific combinations of method operations or system elements, these operations and elements can be combined in different ways to achieve the same purpose. The operations, elements, and functions described with respect to one embodiment are not intended to exclude similar roles in other embodiments or embodiments.

[0088] The expressions and terms used herein are for the purpose of explanation and should not be regarded as limiting. In this specification, the use of "comprising", "configured", "having", "containing", "accompanying", "characteristic", "having a feature", "characterized by" and variations thereof is intended to include not only the items listed thereafter, corresponding items and additional items, but also alternative embodiments consisting only of the items listed thereafter. In one embodiment, the systems and methods described herein are composed of one, one or more combinations, or all of the elements, operations, or components described.

[0089] All references to embodiments or elements or operations of systems and methods referred to in the singular herein may include embodiments that include these plural elements, and all references to embodiments or elements or operations referred to in the plural herein may include embodiments that include only a single element. References in the singular or plural are not intended to limit the presently disclosed systems or methods, their components, operations or elements to a singular or plural configuration. References to operations or elements based on any information, operation, or element may include embodiments in which the operation or element is at least partially based on any information, operation, or element.

[0090] Any embodiment disclosed in this specification may be combined with any other embodiment or embodiments, and references to "embodiment", "some embodiments", "one embodiment", etc. are not necessarily mutually exclusive, and are understood to be for the purpose of indicating that the particular features, structures, or characteristics described in connection with the embodiments may be included in at least one embodiment or embodiments. These terms as used herein do not necessarily all refer to the same embodiment. Any embodiment may be combined inclusively or exclusively with other embodiments in a manner consistent with the aspects and embodiments disclosed herein.

[0091] When reference signs are attached after the technical features in the drawings, the detailed description, or any claims, the reference signs are included to enhance the clarity of the drawings, the detailed description, and the claims. Therefore, the presence or absence of reference signs has no limiting effect on the scope of the elements of the claims.

[0092] The systems and methods described herein can be embodied in other specific forms without departing from their characteristics. Additional descriptions of relative parallel, perpendicular, vertical, or other positions or directions include variations within + / - 10% or + / - 10 degrees of a purely vertical, parallel, or perpendicular position. References to "approximately", "about", "substantially", or other terms of degree include variations of + / - 10% from the given measurement, unit, or range, unless explicitly indicated otherwise. The combined elements may be electrically, mechanically, or physically coupled to each other directly or through intervening elements. Therefore, the scope of the systems and methods described herein is represented by the appended claims rather than the foregoing description, and changes within the meaning and scope of equivalence of the claims are included therein.

[0093] The term "coupled" and its variations include coupling two members directly or indirectly to each other. Such coupling may be fixed (e.g., permanent or stationary) or movable (e.g., removable or separable). This coupling can consist of ways in which the two members are directly or indirectly coupled to each other, the two members are coupled to each other using another intervening member, the two members are coupled to each other using an additional intermediate member, or the two members are coupled to each other using an intervening member formed as a single unitary body with one of the two members. When "coupled" or its variations are modified by additional terms (e.g., directly coupled), the general definition of "coupled" provided above is modified to be a narrower meaning than the general definition of "coupled" provided above by the plain language meaning of the additional term (e.g., "directly coupled" means the coupling of two members without a separate intervening member). Such coupling can be mechanical, electrical, or fluidic coupling.

[0094] References to "or" can be interpreted inclusively, so all terms described using "or" can represent one, more than one, and all of the terms described. References to "at least one of 'A' or 'B'" can include only 'A', only 'B', and both 'A' and 'B'. Such references used with "comprising" or other open-ended terms can include additional items.

[0095] Modifications of the described elements and operations such as the size, dimensions, structure, shape and ratio of various elements, values of parameters, mounting arrangements, use of materials, color, change of direction may occur without substantially departing from the teachings and advantages of the content disclosed herein. For example, elements shown as integrally formed can be composed of a number of parts or elements, the position of the elements can be reversed or changed, and the characteristics or number of individual elements or positions can be varied or changed. Also, other alternatives, modifications, changes and omissions in the design, operating conditions and arrangements of the disclosed elements and operations can be made without departing from the scope of the present disclosure.

[0096] References in this specification to the position of elements (e.g., "upper", "lower", "above", "below") are used merely to describe the orientation of various elements in the drawings. Note that the orientation of the various elements may vary according to other exemplary embodiments, and such variations are intended to be encompassed by the present disclosure.

Claims

1. A laser source configured to generate a beam, and a polygon scanner rotatable about an axis, wherein the polygon scanner, has a first frame surface and a second frame surface centered on the axis, and has at least one frame portion between the first frame surface and the second frame surface, and the first frame surface and the second frame surface are flat, and the frame, and a plurality of mirrors coupled to the frame, each mirror being made of a glass material, and including a central portion of the inner surface of a first mirror among the plurality of mirrors coupled to the first frame surface, and a central portion of the inner surface of a second mirror among the plurality of mirrors coupled to the second frame surface, the at least one frame portion is spaced from the inner surface of the first mirror, forms a curve from the first frame surface, and the central portion of the first mirror is coupled to the first frame surface by an adhesive, the adhesive has a coefficient of thermal expansion substantially the same as that of the first mirror, the first mirror extends further than the first frame surface in a direction along the axis, the first mirror has a first edge adjacent to a second edge of the second mirror, and there is a gap between the first edge and the second edge, a LIDAR system.

2. The LIDAR system according to claim 1, wherein each mirror comprises a polished glass material.

3. The LIDAR system according to claim 1, further comprising a modulator configured to receive the beam, modulate at least one of a phase or a frequency of the beam, and output the modulated beam to the polygon scanner.

4. The distortion of at least one of the plurality of mirrors with respect to the plane of the at least one mirror is from 0 nanometers (nm) to less than about 200 nanometers in a temperature range of about minus 20 degrees Celsius to about 50 degrees Celsius for the LIDAR system according to claim 1.

5. The frame rotates about the axis, and the direction is parallel to the axis for the LIDAR system according to claim 1.

6. The first edge is located at a predetermined distance from the frame for the LIDAR system according to claim 1.

7. The first edge and the second edge form an angle such that the size of the gap decreases in a direction away from the axis for the LIDAR system according to claim 1.

8. An autonomous vehicle control system, The system is, A laser source configured to generate a first beam, A polygon scanner rotatable about an axis - the polygon scanner includes a frame and a plurality of mirrors coupled to the frame, the frame has a first frame surface and a second frame surface about the axis, and the first frame surface and the second frame surface are flat, The frame includes at least one frame portion between the first frame surface and the second frame surface, Each mirror is made of a glass material and includes a central portion of the inner surface of a first mirror among the plurality of mirrors coupled to the first frame surface and a central portion of the inner surface of a second mirror among the plurality of mirrors coupled to the second frame surface, The at least one frame portion is separated from the inner surface of the first mirror, forms a curve from the first frame surface, and the central portion of the first mirror is coupled to the first frame surface by an adhesive, The adhesive has a coefficient of thermal expansion substantially the same as that of the first mirror. The first mirror extends further than the surface of the first frame in the direction along the axis. The polygon scanner is configured to reflect the first beam as a second beam. The first mirror has a first edge adjacent to a second edge of the second mirror, and there is a gap between the first edge and the second edge. including one or more processors. The one or more processors use a third beam received from at least one of reflection or scattering of the second beam by an object to determine at least one of the distance of the object or the speed of the object. An autonomous driving vehicle control system that controls the operation of an autonomous driving vehicle in response to at least one of the distance or the speed.

9. The autonomous driving vehicle control system according to claim 8, further including a motor configured to rotate the polygon scanner.

10. The autonomous driving vehicle control system according to claim 8, wherein the one or more processors are configured to determine the distance of the object based on the time of flight related to the second beam and the third beam.

11. Each mirror includes a polished glass material. The autonomous driving vehicle control system according to claim 8.

12. The autonomous driving vehicle control system according to claim 8, further including a modulator configured to receive the first beam, modulate at least one of the phase or frequency of the first beam, and output the modulated first beam to the polygon scanner.

13. The autonomous driving vehicle control system according to claim 8, wherein the first mirror is made of a material in which the distortion of the first mirror with respect to the plane of the first mirror is from 0 nanometers (nm) to less than about 200 nanometers in a temperature range of about minus 20 degrees Celsius to about 50 degrees Celsius.

14. An autonomous driving vehicle, wherein the vehicle comprises a LiDAR system, and the LiDAR system a laser source configured to generate a first beam, and a polygon scanner rotatable about an axis - the polygon scanner includes a frame and a plurality of mirrors coupled to the frame, the frame has a first frame surface centered on the axis and a second frame surface centered on the axis, the first frame surface and the second frame surface are flat, the frame includes at least one frame portion between the first frame surface and the second frame surface, each mirror is made of a glass material, and includes a central portion of the inner surface of the first mirror among the plurality of mirrors coupled to the first frame surface and a central portion of the second mirror among the plurality of mirrors coupled to the second frame surface, the at least one frame portion is spaced from the inner surface of the first mirror and forms a curve from the first frame surface, and the central portion of the first mirror is coupled to the first frame surface by an adhesive, the adhesive has a thermal expansion coefficient substantially the same as that of the first mirror, and the first mirror extends further than the first frame surface in a direction along the axis, the polygon scanner is configured to reflect the first beam to output a second beam, the first mirror has a first edge adjacent to a second edge of the second mirror, and there is a gap between the first edge and the second edge - and, a steering system, and a brake system, and a vehicle controller including one or more processors. The vehicle controller is, using a third beam received from at least one of reflection or scattering of the second beam by an object to determine at least one of the distance to the object or the speed of the object, an autonomous vehicle that controls the operation of at least one of the steering system and the braking system in response to at least one of the distance or the speed.

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