LIDAR system

Abstract

A light detection and ranging (LIDAR) 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 comprising a glass material. At least one aspect relates to an autonomous vehicle control system. The autonomous vehicle control system includes the laser source, the polygon scanner, and one or more processors.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of and priority to U.S. Patent Application No. 17 / 592,286, filed February 3, 2022. The entire disclosure of U.S. Patent Application No. 17 / 592,286 is incorporated herein by reference. Background Art

[0003] Optical detection of range using lasers, often referred to by the mnemonic LIDAR (for "light detection and ranging") and sometimes also called "laser RADAR," is used for a variety of applications, including imaging and collision avoidance. Compared to conventional microwave ranging systems, such as radio wave detection and ranging (RADAR), LIDAR provides finer-scale range resolution with smaller beam sizes. Summary of the Invention

[0004] At least one aspect relates to a light detection and ranging (LIDAR) system. The LIDAR system includes a laser source configured to generate a beam and a polygon scanner. The polygon scanner includes a frame and a plurality of mirrors coupled to the frame, each mirror comprising a glass material.

[0005] 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 comprising a glass material. The polygon scanner is configured to reflect the first beam into a second beam. The one or more processors are configured to use a third beam received from at least one of reflection or scattering of the second beam by the object to determine at least one of a range to an object or a velocity of the object, and to control operation of the autonomous vehicle in response to at least one of the range or the velocity.

[0006] At least one aspect relates to an autonomous vehicle. The autonomous vehicle includes a LIDAR system comprising a laser source configured to generate a first beam and a polygon scanner comprising a frame and a plurality of mirrors coupled to the frame, each mirror comprising a glass material. The autonomous vehicle includes a steering system, a braking system, and a vehicle controller comprising one or more processors configured to determine at least one of a range to an object or a velocity of the object using a third beam received from at least one of a reflection or scattering of a second beam by the object, and to control operation of at least one of the steering system and the braking system in response to at least one of the range or velocity.

[0007] Those skilled in the art will appreciate that this summary is illustrative only and is not intended to be limiting in any way. Any feature described herein may be used in conjunction with any other feature, and any subset of these features may be used in combination according to various embodiments. Other aspects, inventive features, and advantages of the apparatus and / or process described herein, which are limited only by the claims, will become apparent from the detailed description set forth herein and taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings in which like reference numerals refer to similar elements and in which:

[0009] Figure 1A is a block diagram of an example of a system environment for an autonomous vehicle;

[0010] Figure 1B is a block diagram of an example of a system environment for an autonomous commercial trucking vehicle;

[0011] Figure 1C is a block diagram of an example of a system environment for an autonomous commercial trucking vehicle;

[0012] Figure 1D is a block diagram of an example of a system environment for an autonomous commercial trucking vehicle;

[0013] Figure 2 is a block diagram of an example of a LIDAR system;

[0014] Figure 3 is a perspective view of an example of a polygon scanner used in a LIDAR system.

[0015] Figure 4 yes Figure 3 Exploded view of a polygon scanner.

[0016] Figure 5 yes Figure 3 Exploded view of a polygon scanner from above.

[0017] Figure 6 This is a diagram showing an example of a heat load test of a polygon scanner.

[0018] Figure 7 This is a diagram showing an example of a polygon scanner combination test.

[0019] Figure 8 This is a diagram showing an example of a mirror displacement test of a polygon scanner. DETAILED DESCRIPTION

[0020] The LIDAR system can generate and transmit a light beam that can be reflected or otherwise scattered by an object into a return beam corresponding to the transmitted beam. The LIDAR system can receive the return beam and process the return beam or its characteristics to determine parameters about the object, such as range and velocity. The LIDAR system can apply various frequency or phase modulations to the transmitted beam, which can facilitate correlating the return beam with the transmitted beam to determine parameters about the object.

[0021] A LIDAR system may 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 comprising a glass material. The mirrors may reflect the first beam to output a second beam, which may be scanned across a field of view to be reflected or otherwise scattered by an object into a third beam. The third beam may be used to determine range, velocity, and Doppler information about the object, such as for controlling the operation of an autonomous vehicle.

[0022] Systems and methods according to the present disclosure can implement a LIDAR system in which, in contrast to polygon scanners that are formed by machining (e.g., computer numerical control (CNC) processes) (such as by diamond-turning aluminum), the polygon scanner in the LIDAR system is assembled using multiple facets of a polished glass mirror attached to a frame. By using a polished glass mirror for the facets, the surface of the facets can be made flatter and less rough, which can achieve optical improvements such as higher reflectivity, lower scattering, and / or a more specific beam shape desirable for autonomous vehicles (e.g., a beam shape with less variation from an ideal Gaussian beam). For example, making the facets flatter and / or less rough can reduce the likelihood of reflections or scattering occurring within the surface of the facets themselves (such reflections or scattering can have a Doppler shift or otherwise contribute noise to signal processing). Additionally, compared to polygon scanners made from a solid block of metal, assembled polygon scanners can have reduced weight and / or inertia, which can improve the reliability of the motor that rotates the polygon scanner and allow for greater flexibility in the form factor of the facet (e.g., allowing for larger facets or facets of various shapes, such as concave or convex facets). Assembled polygon scanners can also be manufactured using less complex, more scalable processes. However, the advantages of assembled polygon scanners described above are not limited to autonomous vehicles. They are advantageous for any type of vehicle equipped with a LIDAR sensor.

[0023] 1. System environment for autonomous vehicles

[0024] Figure 1A is a block diagram illustrating an example of a system environment for an autonomous vehicle according to some implementations. Figure 1AAn example autonomous vehicle 100 is depicted in which the various techniques disclosed herein may be implemented. Vehicle 100 may include, for example, a powertrain 102 including a prime mover 104 powered by an energy source 106 and capable of providing power to a drivetrain 108, and a control system 110 including a steering control 112, a powertrain control 114, and a braking control 116. Vehicle 100 may be implemented as any number of different types of vehicles, including vehicles capable of transporting people and / or cargo and operating in a variety of environments. The aforementioned components 102-116 may vary widely based on the type of vehicle in which they are utilized, such as a wheeled land vehicle such as a car, van, truck, or bus. Prime mover 104 may include one or more electric motors and / or an internal combustion engine (among others). The energy source may include, for example, a fuel system (e.g., providing gasoline, diesel, hydrogen, etc.), a battery system, solar panels or other renewable energy sources, and / or a fuel cell system. The drivetrain 108 may include wheels and / or tires and a transmission and / or any other mechanical drive components to convert the output of the prime mover 104 into vehicle motion, as well as one or more brakes configured to controllably stop or slow the vehicle 100 and steering or steering components suitable for controlling the trajectory of the vehicle 100 (e.g., a rack and pinion steering linkage that enables one or more wheels of the vehicle 100 to pivot about a generally vertical axis to change the angle of the wheel's plane of rotation relative to the longitudinal axis of the vehicle). In some embodiments, a combination of powertrains and energy sources may be used (e.g., in the case of an electric / gas hybrid vehicle), and in some cases, multiple electric machines (e.g., dedicated to individual wheels or axles) may be used as prime movers.

[0025] The directional control 112 may include one or more actuators and / or sensors for controlling and receiving feedback from directional or steering components to enable the vehicle 100 to follow a desired trajectory. The powertrain control 114 may be configured to control the output of the powertrain 102, for example, controlling the output power of the prime mover 104, controlling the gear of the transmission in the transmission 108, etc., thereby controlling the speed and / or direction of the vehicle 100. The brake control 116 may be configured to control one or more brakes that slow or stop the vehicle 100, for example, disc or drum brakes coupled to the vehicle's wheels.

[0026] Other vehicle types, including but not limited to off-road vehicles, all-terrain or tracked vehicles, and construction equipment, may utilize different powertrains, drivetrains, energy sources, directional controls, powertrain controls, and braking controls. Furthermore, in some embodiments, some components may be combined, for example, where directional control of the vehicle is primarily handled by varying the output of one or more prime movers.

[0027] Various levels of autonomous control of the vehicle 100 may be implemented in a vehicle control system 120, which may include one or more processors 122 and one or more memories 124, where each processor 122 is configured to execute program code instructions 126 stored in the memories 124. The processors may include, for example, a graphics processing unit (“GPU”) and / or a central processing unit (“CPU”).

[0028] Sensors 130 may include various sensors suitable for collecting information from the vehicle's surroundings for use in controlling vehicle operation. For example, sensors 130 may include a radar sensor 134, a LIDAR (Light Detection and Ranging) sensor 136, and a 3D positioning sensor 138, such as an accelerometer, gyroscope, magnetometer, or any of a variety of satellite navigation systems (such as GPS (Global Positioning System), GLONASS (Global Navigation Satellite System), BeiDou Navigation Satellite System (BDS), Galileo, Compass, etc.). 3D positioning sensor 138 can be used to determine the vehicle's position on Earth using satellite signals. Sensors 130 may include a camera 140 and / or an IMU (Inertial Measurement Unit) 142. Camera 140 may be monoscopic or stereoscopic and can record still and / or video images. IMU 142 may include multiple gyroscopes and accelerometers capable of detecting linear and rotational motion of the vehicle in three directions. One or more encoders (not shown), such as wheel encoders, may be used to monitor the rotation of one or more wheels of vehicle 100. Each sensor 130 may output sensor data at various data rates, which may be different from the data rates of other sensors 130 .

[0029] The output of the sensors 130 may be provided to a set of control subsystems 150, including a positioning subsystem 152, a planning subsystem 156, a perception subsystem 154, and a control subsystem 158. The positioning subsystem 152 may perform functions such as accurately determining the position and orientation (sometimes referred to as "pose") of the vehicle 100 within its surrounding environment, typically within a reference frame. The position of the autonomous vehicle may be compared with the positions of additional vehicles in the same environment as part of generating labeled autonomous vehicle data. The perception subsystem 154 may perform functions such as detecting, tracking, identifying, and / or recognizing objects within the environment surrounding the vehicle 100. Machine learning models according to some embodiments may be used to track objects. The planning subsystem 156 may perform functions such as planning a trajectory for the vehicle 100 within a certain timeframe, given a desired destination and static and moving objects within the environment. Machine learning models according to some embodiments may be used to plan the vehicle trajectory. The control subsystem 158 may perform functions such as generating appropriate control signals for controlling various controls in the vehicle control system 120 to achieve the planned trajectory of the vehicle 100. A machine learning model can be utilized to generate one or more signals to control the autonomous vehicle to achieve the planned trajectory.

[0030] Figure 1A The multiple sensors of various types shown can be used for redundancy and / or to cover different areas around the vehicle, and other types of sensors may be used. Various types and / or combinations of control subsystems may be used. Some or all of the functionality of the subsystems 152-158 may be implemented using program code instructions 126 residing in one or more memories 124 and executed by one or more processors 122, and these subsystems 152-158 may, in some cases, be implemented using the same processor and / or memory. The subsystems may be implemented, at least in part, using various dedicated circuit logic, various processors, various field programmable gate arrays ("FPGAs"), various application specific integrated circuits ("ASICs"), various real-time controllers, etc. As described above, multiple subsystems may utilize circuits, processors, sensors, and / or other components. In addition, the various components in the vehicle control system 120 may be networked in various ways.

[0031] In some embodiments, the vehicle 100 may also include a secondary vehicle control system (not shown), which may serve as a redundant or backup control system for the vehicle 100. In some embodiments, the secondary vehicle control system may be capable of fully operating the autonomous vehicle 100 in the event of an adverse event in the vehicle control system 120, while in other embodiments, the secondary vehicle control system may have only limited functionality, such as performing a controlled stop of the vehicle 100 in response to detecting an adverse event in the primary vehicle control system 120. In other embodiments, the secondary vehicle control system may be omitted.

[0032] Various architectures including various combinations of software, hardware, circuit logic, sensors, and networks can be used to implement Figure 1A . Each processor may be implemented as, for example, a microprocessor, and each memory may represent a random access memory ("RAM") device that includes primary storage, as well as any supplementary levels of memory, such as cache memory, non-volatile or backup memory (e.g., programmable or flash memory), read-only memory, etc. Additionally, each memory may be considered to include memory storage physically located elsewhere in the vehicle 100, such as any cache memory in a processor, as well as any storage capacity used as virtual memory, such as stored on a mass storage device or another computer controller. Figure 1A One or more of the processors shown, or an entirely separate processor, may be used to implement additional functionality in the vehicle 100 beyond the purpose of autonomous control, for example, to control entertainment systems, operate doors, lights, convenience features, etc.

[0033] Additionally, for additional storage, the vehicle 100 may include one or more mass storage devices, such as, for example, a removable disk drive, a hard drive, a direct access storage device (“DASD”), an optical disk drive (e.g., a CD drive, a DVD drive, etc.), a solid-state storage drive (“SSD”), a network attached storage, a storage area network, and / or a tape drive, among others.

[0034] Additionally, the vehicle 100 may include a user interface 164 to enable the vehicle 100 to receive various inputs from and generate outputs for a user or operator, such as one or more displays, touch screens, voice and / or gesture interfaces, buttons and other tactile controls, etc. Otherwise, user input may be received via another computer or electronic device (e.g., via an application on a mobile device or via a web interface).

[0035] In addition, the vehicle 100 may include one or more network interfaces, such as network interface 162, which is adapted to 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, etc.) to allow information communication with other computers and electronic devices (including, for example, a central server, such as a cloud server), from which the vehicle 100 receives environmental and other data for its autonomous control. Data collected by one or more sensors 130 may be uploaded to a computing system 172 via network 170 for additional processing. In some embodiments, a timestamp may be added to each instance of vehicle data prior to upload.

[0036] Figure 1AEach of the processors illustrated in FIG100 , as well as the various additional controllers and subsystems disclosed herein, typically operates under the control of an operating system and executes or otherwise relies on various computer software applications, components, programs, objects, modules, data structures, etc., as will be described in greater detail below. In addition, the various applications, components, programs, objects, modules, etc. may also be executed on one or more processors in another computer coupled to the vehicle 100 via the network 170, such as in a distributed, cloud-based, or client-server computing environment, whereby the processing required to implement the functionality of the computer program may be distributed across the network to multiple computers and / or servers.

[0037] In general, the routines executed to implement the various embodiments described herein, whether implemented as part of an operating system or as a specific application, component, program, object, module, or sequence of instructions, or even a subset thereof, will be referred to herein as "program code." The program code may include 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, performs the steps necessary to perform the steps or elements embodying various aspects of the present disclosure. Furthermore, while the embodiments have been and will be described hereinafter in the context of fully functional computers and systems, it should be understood that the various embodiments described herein are capable of being distributed as a program product in a variety of forms, and that the embodiments may be implemented regardless of the particular type of computer-readable medium used to actually carry out the distribution.

[0038] 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 drives, magnetic tapes, and optical disks (e.g., CD-ROMs, DVDs, etc.), etc.

[0039] In addition, the various program codes described below may be identified based on the application within which they are implemented in a particular embodiment. Any specific program nomenclature below is used for convenience only, and thus the present disclosure should not be limited to use solely in any specific application identified and / or implied by such nomenclature. Furthermore, given the countless ways in which computer programs can generally be organized into routines, procedures, methods, modules, objects, and the like, and the various ways in which program functionality can be distributed among the various software layers (e.g., operating systems, libraries, APIs, applications, applets, etc.) residing within a typical computer, the present disclosure is not limited to the specific organization and distribution of program functionality described herein.

[0040] 2. LIDAR for automotive applications

[0041] Trucks can include LIDAR systems (e.g. Figure 1A The vehicle control system 120 in Figure 2LIDAR system 200 in

[15] , etc.). In some embodiments, a LIDAR system may use frequency modulation to encode a light signal and use optics to scatter the coded light signal into free space. By detecting the frequency difference between the coded light signal and the return signal reflected from an object, a frequency modulated (FM) LIDAR system can use the Doppler effect to determine the object's position and / or accurately measure the object's velocity. In some embodiments, an FM LIDAR system may use continuous wave (referred to as "FMCW LIDAR") or quasi-continuous wave (referred to as "FMQW LIDAR"). In some embodiments, a LIDAR system may use phase modulation (PM) to encode a light signal and use optics to scatter the coded light signal into free space.

[0042] In some cases, an object (e.g., a pedestrian wearing dark clothing) may have low reflectivity because it reflects only a small amount (e.g., 10% or less) of the light that strikes the object back to the sensor of the FM or PM LIDAR system (e.g., Figure 1A In other cases, an object (e.g., a lighted road sign) may have a high reflectivity (e.g., greater than 10%) because it reflects a significant amount of light striking the object back toward the sensor of the FM LIDAR system.

[0043] Regardless of the reflectivity of the object, the FM LIDAR system may be able to detect (e.g., classify, identify, find, etc.) objects at a greater distance (e.g., 2x) than a conventional LIDAR system. For example, the FM LIDAR system may detect low-reflectivity objects at over 300 meters and high-reflectivity objects at over 400 meters.

[0044] To achieve this improvement in detection capabilities, FM LIDAR systems can use sensors such as Figure 1A Sensors 130 in FIG. In some embodiments, these sensors can be single-photon sensitive, meaning they can detect the smallest possible amount of light. While FM LIDAR systems can use infrared wavelengths (e.g., 950 nm, 1550 nm, etc.) in some applications, they are not limited to the infrared wavelength range (e.g., near infrared: 800 nm-1500 nm; mid-infrared: 1500 nm-5600 nm; and far infrared: 5600 nm-1,000,000 nm). By operating an FM or PM LIDAR system at infrared wavelengths, the system can broadcast more intense light pulses or beams than conventional LIDAR systems.

[0045] Therefore, by detecting objects at greater distances, FM LIDAR systems can have more time to react to unexpected obstacles. In fact, even a few milliseconds of additional time can improve response time and comfort, especially for heavy vehicles (such as commercial trucking vehicles) traveling at highway speeds.

[0046] FM LIDAR systems can instantly provide accurate velocity for each data point. In some implementations, velocity measurement is achieved using the Doppler effect, which shifts the frequency of light received from an object based on at least one of the velocity in a radial direction (e.g., the direction vector between the detected object and the sensor) or the frequency of the laser signal. For example, for speeds encountered in road conditions less than 100 meters per second (m / s), this shift corresponds to a frequency shift of less than 130 megahertz (MHz) at a wavelength of 1550 nanometers (nm). This frequency shift is so small that it is difficult to detect directly in the optical domain. However, by using coherent detection in FMCW, PMCW, or FMQW LIDAR systems, the signal can be converted to the RF domain, allowing the frequency shift to be calculated using various signal processing techniques. This enables the autonomous vehicle control system to process incoming data more quickly.

[0047] Instantaneous velocity calculations also make it easier for FM LIDAR systems to identify distant or sparse data points as objects and / or to track how these objects move over time. For example, FM LIDAR sensors (e.g., Figure 1A A sensor 130 in FIG. 1 may receive only a few returns on an object 300 m away (e.g., a collision), but if those returns give velocity values ​​of interest (e.g., moving toward the vehicle at >70 mph), the FM LIDAR system and / or autonomous vehicle control system can determine a corresponding weight for the probability of being associated with the object.

[0048] Faster identification and / or tracking by the FM LIDAR system gives the autonomous vehicle control system more time to maneuver the vehicle. A better understanding of how fast an object is moving also allows the autonomous vehicle control system to plan better responses.

[0049] Compared to conventional LIDAR systems, FM LIDAR systems can be less static. That is, conventional LIDAR systems, designed to be more light-sensitive, often perform poorly in bright sunlight. These systems also tend to suffer from crosstalk (e.g., when sensors are confused by each other's light pulses or beams) and self-interference (e.g., when a sensor is confused by its own previous light pulses or beams). To overcome these shortcomings, vehicles using conventional LIDAR systems often require additional hardware, complex software, and / or more computing power to manage this "noise."

[0050] In contrast, FM LIDAR systems don't suffer from these types of issues because each sensor is specifically designed to respond only to its own light characteristics (e.g., light beam, light wave, light pulse). If the returning light doesn't match the timing, frequency, and / or wavelength of the originally transmitted light, the FM sensor can filter (e.g., remove, ignore, etc.) that data point. Consequently, FM LIDAR systems produce (e.g., generate, derive, etc.) more accurate data with less hardware or software requirements, leading to smoother driving.

[0051] FM LIDAR systems can be more easily scaled than conventional LIDAR systems. As more autonomous vehicles (e.g., cars, commercial trucks, etc.) appear on the road, those powered by FM LIDAR systems may not have to contend with interference issues from sensor crosstalk. Furthermore, FM LIDAR systems use less optical peak power than conventional LIDAR sensors. This allows some or all optical components for FM LIDAR to be produced on a single chip, which has its own benefits, as discussed in this article.

[0052] 2.1 Commercial Trucking

[0053] Figure 1B is a block diagram illustrating an example system environment for an autonomous commercial trucking vehicle, according to some embodiments. Environment 100B includes a commercial truck 102B configured to haul freight 106B. In some embodiments, commercial truck 102B may include a vehicle configured for long-haul freight, regional freight, intermodal freight (i.e., where a road-based vehicle is used as one of multiple modes of transportation to move freight), and / or any other road-based freight application. In some embodiments, commercial truck 102B may be a flatbed truck, a refrigerated truck (e.g., a refrigerator truck), a ventilated van (e.g., a dry van), a moving truck, etc. In some embodiments, freight 106B may be freight and / or agricultural products. In some embodiments, commercial truck 102B may include a trailer for carrying freight 106B, such as a flatbed, a small box trailer, a step trailer, an extendable flatbed, a side-loader, etc.

[0054] Environment 100B includes objects 110B within a distance range of 30 meters or less from the truck (in Figure 1B Another vehicle is shown).

[0055] The commercial truck 102B may include a LIDAR system 104B (eg, an FM LIDAR system, a Figure 1A The vehicle control system 120 in Figure 2LIDAR system 200 in FIG. 2 ). Although Figure 1B While one LIDAR system 104B is shown mounted on the front of the commercial truck 102B, the number of LIDAR systems and the areas where the LIDAR systems are mounted on the commercial truck are not limited to a specific number or area. The commercial truck 102B may include any number of LIDAR systems 104B (or components thereof, such as sensors, modulators, coherent signal generators, etc.) mounted to any area (e.g., the front, rear, sides, top, bottom, lower, and / or floor) of the commercial truck 102B to facilitate detecting objects in any free space relative to the commercial truck 102B.

[0056] As shown, LIDAR system 104B in environment 100B may be configured to detect objects (eg, another vehicle, a bicycle, a tree, a street sign, a pothole, etc.) at a short distance (eg, 30 meters or less) from commercial truck 102B.

[0057] Figure 1C 1 is a block diagram illustrating an example of a system environment for an autonomous commercial trucking vehicle, according to some embodiments. Environment 100C includes the same components included in environment 100B (eg, commercial truck 102B, cargo 106B, LIDAR system 104B, etc.).

[0058] Environment 100C includes objects 110C within a distance range of (i) greater than 30 meters and (ii) equal to or less than 150 meters from commercial truck 102B. Figure 1C As shown, LIDAR system 104B in environment 100C may be configured to detect objects (e.g., another vehicle, a bicycle, a tree, a street sign, a pothole, etc.) at a distance (e.g., 100 meters) from commercial truck 102B.

[0059] Figure 1D 1 is a block diagram illustrating an example of a system environment for an autonomous commercial trucking vehicle, according to some embodiments. Environment 100D includes the same components included in environment 100B (eg, commercial truck 102B, cargo 106B, LIDAR system 104B, etc.).

[0060] Environment 100D includes object 110D within a distance greater than 150 meters from commercial truck 102B ( Figure 1D As shown, LIDAR system 104B in environment 100D may be configured to detect objects (e.g., another vehicle, a bicycle, a tree, a street sign, a pothole, etc.) at a distance (e.g., 300 meters) from commercial truck 102B.

[0061] In commercial trucking applications, it is important to effectively detect objects at all ranges due to the increased weight and, consequently, the longer stopping distances required for such vehicles. FM LIDAR systems (e.g., FMCW and / or FMQW systems) or PM LIDAR systems are well-suited for commercial trucking applications due to the advantages described above. As a result, commercial trucks equipped with such systems can have enhanced capabilities for moving people and cargo over short or long distances. In various embodiments, such FM or PM LIDAR systems can be used in semi-autonomous applications, where the commercial truck has a driver and some functions of the commercial truck use the FM or PM LIDAR system, or in fully autonomous applications, where the commercial truck is operated entirely autonomously by the FM or PM LIDAR system, either alone or in combination with other vehicle systems.

[0062] 3. LIDAR system

[0063] Figure 2 An example of a LIDAR system 200 is depicted. The LIDAR system 200 can be used to determine parameters about an object, such as range 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 the vehicle in response to the received parameters, or a display that can present a representation of the parameters. The LIDAR system 200 can be a coherent detection system. The LIDAR system 200 can be used to implement a reference Figures 1A to 1D

[0046] The various features and components of the system described herein are described herein. The LIDAR system 200 may include components for performing various detection methods, such as operating as an amplitude modular LIDAR system or a coherent LIDAR system. The LIDAR system 200 may be used to perform time-of-flight range determination. In some embodiments, various components or combinations of components of the LIDAR system 200 (such as the laser source 204 and the modulator 214) may be housed in the same housing, disposed in the same circuit board or other electronic component, or otherwise integrated. In some embodiments, various components or combinations of components of the LIDAR system 200 may be provided as separate components, such as by using optical coupling (e.g., optical fiber) for components that generate and / or receive optical signals (such as light beams), or using wired or wireless electronic connections for components that generate and / or receive electrical (e.g., data) signals.

[0064] LIDAR system 200 may include a laser source 204 that generates and emits a beam 206, such as a carrier beam. A beam splitter 208 may split beam 206 into a beam 210 and a reference beam 212 (e.g., a reference signal). In some embodiments, any suitable optical, electronic, or optoelectronic components may be used to provide beam 210 and reference beam 212 from laser 204 to other components.

[0065] The modulator 214 can modulate one or more characteristics 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., an optical frequency corresponding to a wavelength of light, where c = λv, where c is the speed of light, λ is the wavelength, and v is the frequency). For example, the modulator 214 can linearly modulate the frequency of the input beam 210 so that the frequency of the beam 216 increases or decreases linearly over time. As another example, the modulator 214 can nonlinearly (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 characteristics of the beam. Return Figure 2 , modulator 214 can modulate beam 210 after beam splitter 208 separates beam 206 so that reference beam 212 is not modulated, or modulator 214 can modulate beam 206 and provide the modulated beam to beam splitter 208 so that beam splitter 208 separates it into a target beam and a reference beam.

[0066] The beam 216 used to output the transmitted signal may have most of the energy of the beam 206 output by the laser source 204, while the reference beam 212 may have significantly less energy, but has sufficient energy to enable mixing with the return beam 248 (e.g., return light) scattered from the object. The reference beam 212 may serve as a local oscillator (LO) signal. The reference beam 212 passes through a reference path and may be provided to the mixer 260. The amplifier 220 may amplify the beam 216 to output a beam 222, and the collimator 224 may collimate the beam 222 to output a beam 226.

[0067] like Figure 2 As shown, a circulator 228 can be positioned between the collimator 224 and the optics 232 to receive the beam 226 and output the beam 230 to the optics 232. The circulator 228 can be between the laser source 204 and the collimator 224. The circulator 228 can receive a return beam 248 from the optics 232 and provide the return beam 248 to the mixer 260. The optics 232 can be a scanning optic, such as one or more polygonal reflectors or deflectors, to adjust the angle of the received beam relative to the output beam based on the orientation of an outer surface (e.g., facets) of the optic relative to the received beam, or a solid-state component (e.g., a phased array, an electro-optic crystal) configured to modify the direction of the received light.

[0068] Optics 232 can define a field of view 244 corresponding to the angle scanned (e.g., swept) by beam 242 (e.g., a transmitted beam). For example, beam 242 can be scanned in a particular plane (e.g., an azimuth plane or an elevation plane) (e.g., relative to an object to which LIDAR system 200 is coupled, such as an autonomous vehicle). Optics 232 can be oriented such that field of view 244 sweeps the azimuth plane relative to optics 232.

[0069] At least one motor 240 can be coupled to the optical device 232 to control at least one of a position or orientation of the optical device 232 relative to the beam 230. For example, where the optical device 232 includes a reflector or a deflector, the motor 240 can rotate the optical device 232 such that a surface of the optical device 232 where the beam 230 is received changes in angle or orientation relative to the beam 230, causing the beam 242 to change in angle or direction as the beam 242 is output from the optical device 232.

[0070] Beam 242 may be output from optics 232 and reflected or otherwise scattered by an object (not shown) as return beam 248 (eg, return signal). Return beam 248 may be received on a receive path, which may include circulator 228, and provided to mixer 260.

[0071] The hybrid 260 may be an optical hybrid, such as a 90-degree optical hybrid. The hybrid 260 may receive the reference beam 212 and the return beam 248, and output a signal 264 in response to the reference beam 212 and the return beam 248 by mixing the reference beam 212 and the return beam 248. The signal 264 may include an in-phase (I) component 268 and a quadrature (Q) component 272.

[0072] LIDAR system 200 may include a receiver 276 that receives signal 264 from mixer 260. Receiver 276 may generate signal 280, which may be an electronic (e.g., radio frequency) signal, in response to signal 264. Receiver 276 may include one or more photodetectors that output signal 280 in response to signal 264.

[0073] The LIDAR system 200 may include a processing system 290 that may use a reference Figure 1AThe features of the vehicle control system 120 described above can be implemented. The processing system 290 can process the data received about the return beam 248, such as signal 280, to determine parameters about the object, such as range and velocity. The processing system 290 can include a scanner controller 292 that can provide scanning signals to control the operation of the optical device 232, such as controlling the motor 240 to rotate the optical device 232 to achieve a target scanning pattern, such as a sawtooth scanning pattern or a step function scanning pattern. The processing system 290 can include a Doppler compensator 294 that can determine the sign and magnitude of the Doppler shift associated with the processing return beam 248 and the correction range based thereon and any other corrections. The processing system 290 can include a modulator controller 296 that can send one or more electrical signals to drive the modulator 214.

[0074] Processing system 290 may include or be communicatively coupled to a vehicle controller 298 to control the operation of a vehicle on which LIDAR system 200 is installed (e.g., to provide full or semi-autonomous control of the vehicle). For example, vehicle controller 298 may be implemented by at least one of LIDAR system 200 or the vehicle's control circuitry. Vehicle controller 298 may control the operation of the vehicle in response to at least one of the range to an object or the object's speed determined by processing system 290. For example, vehicle controller 298 may transmit a control signal to at least one of the vehicle's steering system or braking system to control at least one of the vehicle's speed or direction.

[0075] Figures 3 to 5 An example of an optical device 300 for a scanner is depicted. The scanner includes a Figure 2 Optics 232 and motor 240 are depicted. For example, LIDAR system 200 may include one or more scanners to transmit beams to and / or receive beams from an object in order to determine information such as range, velocity, or Doppler effect associated with the object.

[0076] In some embodiments, the optical device 300 can be an assembled polygon that includes a plurality of mirrors 304 coupled to a frame 308. By assembling the optical device 300 from separate components, rather than forming the scanner by machining a block of metal, the optical device 300 can have improved optical and mechanical properties, including mirror form factor flexibility, low weight / inertia for a given mirror size, optical surface quality (e.g., lack of roughness), lower volumetric cost, and robustness with respect to stresses such as thermal, shock, and vibration stresses. For example, by forming the optical device 300 as an assembled device, the scanner can have approximately half the mass and inertia about axis 402 relative to a solid metal scanner with similar or equal mirror size (e.g., a mass of 0.2 kg and inertia of 1.05e-5 kg ​​m). 2 Compared to the inertia of a solid metal scanner, the scanner of the present disclosure has a mass of 0.09 kg and an inertia of 5.2e-5 kg ​​m about axis 402. 2 inertia).

[0077] The reflector 304 can be faceted and can have an outward-facing surface 312 through which an incident beam is received and then reflected by the reflector 304 to be output from the surface 312. The reflector 304 can reflect light for LIDAR applications (e.g., via a laser beam formed on a laser beam). Figure 2 One or more components shown between laser source 204 and optics 232 may reflect light received from laser 204. For example, mirror 304 may reflect light having a wavelength greater than or equal to 1100 nm and less than or equal to 1800 nm, including light at approximately 1550 nm.

[0078] The optical device 300 can include various numbers of reflectors 304. For example, the optical device 300 can include greater than or equal to three and less than or equal to twelve reflectors 304. The reflectors 304 can be arranged around the perimeter 306 of the frame 308, such as to define a polygonal shape. Each reflector 304 can have the same shape as at least one other reflector 304, such as a rectangular shape having the same length and width, a circular or elliptical shape having the same perimeter, a convex or concave polygonal shape having the same number and length of sides, and various other similar or identical shapes.

[0079] The reflectors 304 can be sized to extend outward from the frame 308; for example, the plane of the surface 414 of the frame 308 can intersect the at least one reflector 304 inward from the outer edge 310 of the at least one reflector 304. For example, the reflectors 304 can extend further than the extent of the frame 308 defined by the surface 414. The reflectors 304 can extend further above and below the frame 308 in a reference frame in which at least one of the axis 402 is parallel to gravity or the surface 414 is parallel to the ground. The reflectors 304 can extend further along the axis 402 than the surface 414 (for example, the projection of the reflectors 304 onto the axis 402 or the plane of the axis 402 can be outward from the frame 308). This can increase the total optical surface area of ​​the reflectors 304 available for reflecting an incident beam without increasing the size or weight of the frame 308 due to the assembled configuration of the reflectors 304 and their attachment to the frame 308. In this way, greater flexibility may be achieved for arranging the various components of LIDAR system 200 relative to each other and relative to optics 300, which may enable the overall form factor to be reduced in size.

[0080] Reflector 304 may comprise a glass material. For example, reflector 304 may comprise optical glass, such as crown glass or flint glass. For example, reflector 304 may comprise K9 glass or BK7 glass, which may have improved thermal properties. As another example, reflector 304 may comprise fused silica, which operates efficiently under UV and near-infrared (NIR) light conditions and has a low coefficient of thermal expansion. Reflector 304 may be formed by cutting from a larger glass panel, which may allow for more scalable production of reflector 304.

[0081] In some embodiments, the reflector 304 (e.g., surface 312) can be polished. By using glass for the reflector 304 (e.g., rather than a metal material such as CNC-machined and diamond-turned aluminum), the reflector 304 can be polished with greater flatness and less roughness, and thus have improved optical properties, such as by reducing scattering of incident light by the surface 312 (which can then be reflected by the backing of the reflector 304 and then output from the surface 312, also with reduced scattering). For example, in an example test of scattering of a glass reflector 304 compared to diamond-turned aluminum (the diamond-turned aluminum and glass reflector were each coated with unprotected gold), the polished glass of the reflector 304 was found to have a relative scattering of 0.80 dB, while the metal (diamond-turned aluminum) was found to have a relative scattering of 6.14 dB. Thus, the glass reflector 304 can reduce the likelihood of light beams being scattered within the structure defining the roughness of the surface 312, which can address issues such as Doppler contributions to the beam signal due to scattering. Furthermore, signal processing computational requirements can be reduced because the signal processing required to remove the Doppler component can be reduced or eliminated. In some embodiments, the reflector 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. Rather, any suitable reflective material can be used as the coating material.

[0082] like Figures 3 to 5 As shown, reflector 304 can have a rectangular shape. Depending on the shape of the glass panel from which reflector 304 is fabricated and how reflector 304 is cut or otherwise extracted from the glass panel, reflector 304 can have a variety of shapes or form factors, including concave or convex shapes. For example, the glass panel can be curved, such that reflector 304 is formed into a curved shape (e.g., concave or convex). The shape of reflector 304 extracted from the glass panel can also be controlled to select the shape of reflector 304, such as providing reflector 304 with a rounded edge 310. This allows reflector 304 to direct the received beam in various directions or angles depending on the shape of reflector 304. Reflector 304 can be fabricated so that surface 312 has a relatively larger surface area than when a denser metal is used for reflector 304, without increasing the weight / inertia of reflector 304 (or, alternatively, the weight / inertia can be reduced while maintaining similar dimensions). Furthermore, by using glass to form the reflector 304, the shape or form factor of the reflector 304 may be more easily selected and implemented for a particular application compared to a solid metal scanner.

[0083] In some embodiments, each reflector 304 can extend from a first edge 316 to a second edge 320 and can be arranged such that a gap 324 exists between the respective edges 316, 320 of adjacent reflectors 304. The gap 324 can allow for expansion or other movement or shape changes of the reflectors 304, such as 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 still remains where the edges 316, 320 intersect the surface 312). In some other embodiments, the reflectors 304 can be arranged such that there is no gap between the respective edges 320 of adjacent reflectors 304.

[0084] Frame 308 can be made of a metallic material, such as formed into a metal block. For example, frame 308 can be made of aluminum. Using aluminum for frame 308 can make frame 308 relatively lightweight and easy to manufacture. Frame 308 or portions thereof can be made of various materials, such as plastic or composite materials, that have sufficient rigidity or other material or structural properties at the operating temperature of the LIDAR system to allow efficient force transfer from frame 308 to mirror 304.

[0085] Each reflector 304 can be bonded at a corresponding bonding surface 404 of the frame 308. The bonding surface 404 can be positioned on or define the perimeter 306 of the frame 308. For example, the frame 308 can include a wall 408 (e.g., a perimeter wall) oriented transverse to the axis 402 of the frame 308. The bonding surface 404 can be defined on the wall 408. Figure 3 As shown, bonding surface 404 can extend over corresponding portions of wall 408 such that a portion 412 of wall 408 exists between bonding surface 404 on either side of bonding surface 404. Portion 412 can be spaced apart from inner surface 416 of mirror 304 (in contrast to a solid-form scanner, where no space or gap exists between the reflective surface and the interior portion of the scanner), with the spacing defined in a plane extending through wall 408 and perpendicular to axis 402. Bonding surface 404 can be flat, while portion 412 can be curved or otherwise shaped to extend inwardly from inner surface 416. A central portion of inner surface 416 can couple with bonding surface 404 (e.g., bonding surface 404 can be centrally located on inner surface 416), which can minimize radial effects on mirror 304 or other components due to temperature changes during thermal expansion and contraction.

[0086] An adhesive (e.g., a bonding material) may be provided on bonding surface 404 (e.g., placed on inner surface 416 and / or a central portion of bonding surface 404) to attach mirror 304 to bonding surface 404, which may enable symmetrical thermal expansion (e.g., with relatively low thermally induced expansion stress). For example, an epoxy (such as an applied epoxy) may be used to attach mirror 304 to bonding surface 404. At least one of the material properties of the adhesive and the surface area of ​​bonding surface 404 may be selected such that the attachment force between bonding surface 404 and mirror 304 is greater than an apparent force (e.g., a centrifugal force) generated by rotation of optical device 300 (e.g., rotation of a scanner of optical device 300) that would drive mirror 304 away from bonding surface 404 during operation of optical device 300 due to rotation of optical device 300 about axis 402. For example, the attachment force may be greater than the centrifugal force at the maximum expected rotation rate of the scanner by at least a certain threshold. The adhesive may be selected to have a coefficient of thermal expansion that is similar or approximately equal to that of the reflector 304 , which may improve the performance of the optical device 300 with respect to thermal expansion or contraction.

[0087] The frame 308 may include an axle receiver 420 inwardly from the wall 408. The axle receiver 420 may be a channel or other opening to allow an axle (e.g., Figure 2 4. The shaft or shaft portion (as depicted) coupled to the motor 240 as described above engages the frame 308 so that the motor 240 can cause the shaft to rotate the frame 308 about the axis 402. The motor 240 can be coupled to the frame 308 using various shafts, gears, or other couplings to rotate the frame 308 about the axis 402. The axis 402 can be defined as at least one of extending through the shaft receiver 420, coinciding with the axis of rotation of the motor 240, or coinciding with the axis of rotation of the shaft (e.g., the shaft can rotate about an axis that is offset from the motor 240 due to the use of gears or other components).

[0088] Figures 6 to 8 Depicted are graphs of a study of the performance of the mirror 304 during operation and with respect to various environmental conditions, such as thermal, shock, and vibration conditions. Figures 6 to 8 As shown, the optical device 300 can be designed as described herein to have minimal impact on optical surface quality over a wide temperature range and have low weight / inertia for robustness advantages under shock / vibration (eg, due to operation of the motor 240 ).

[0089] Figure 6A graph 600 depicts the distortion of a mirror 304 under thermal stress relative to thermal load that may be expected for operation of a LIDAR system for automotive applications. For example, at least one mirror 304 may have a distortion of no greater than about 200 nm out of the plane of the mirror 304, such as from 0 nm to about 200 nm. Figure 6 As depicted in FIG, the mirror 304 was found to have distortion (e.g., translation out of the plane of the surface 312) ranging from 101 nm at a temperature of -20 degrees Celsius to 67 nanometers at a temperature of 50 degrees Celsius. Various features of the optical device 300 described herein, such as a centrally located coupling between the mirror 304 and the bonding surface 404 to reduce or minimize stress and distortion affected by the bonding, can achieve this distortion performance.

[0090] Figure 7 Graph 700 depicts a bond peel load. The bond peel load may correspond to a vertical load caused by an impact stress on the optical device 300, such as a shock transmitted from a vehicle to the optical device 300 (e.g., via the motor 240). The optical device 300 may be configured as described herein, such as based on the weight of the mirror 304 and the bond between the mirror 304 and the frame 308, such that, in response to a 50G vertical load, the mirror 304 experiences a bond peel stress of 0.16 MPa (which may correspond to a stress of 16 N / m given the size of the mirror 304).

[0091] Figure 8 Graph 800 depicts the angular displacement of the mirror 304 relative to vibration conditions. Figure 8 As shown, in response to 3G RMS (Root mean square acceleration associated with random vibration), the mirror 304 can have a rigid body tilt of 1.3 nm or an angular displacement of 37.1e-9 radians under vibration of 667 Hz.

[0092] Now that some illustrative embodiments have been described, it will be apparent that the foregoing is illustrative rather than restrictive and has been presented by way of example. In particular, although many of the examples presented herein involve specific combinations of method actions or system elements, those actions and those elements can be combined in other ways to achieve the same objectives. Actions, elements, and features discussed in conjunction with one embodiment are not intended to be excluded from similar roles in other embodiments or implementations.

[0093] The phraseology and terminology used herein are for descriptive purposes and should not be construed as limiting. "Including," "comprising," "having," "containing," "involving," "characterized by," "characterized by," and variations thereof are intended to encompass the items listed thereafter, their equivalents and additional items, and alternative embodiments consisting solely of the items listed thereafter. In one embodiment, the systems and methods described herein consist of each of one of the described elements, actions, or components, a combination of more than one of the described elements, actions, or components, or all of the described elements, actions, or components.

[0094] Any reference to an embodiment or element or action of a system or method referenced herein in the singular may also include embodiments comprising a plurality of such elements, and any reference to any embodiment or element or action in the plural may also include embodiments comprising only a single element. Reference in the singular or plural form is not intended to limit the presently disclosed systems or methods, their components, actions, or elements to a single or multiple configuration. Reference to any action or element based on any information, action, or element may include implementations in which the action or element is based, at least in part, on any information, action, or element.

[0095] Any embodiment disclosed herein may be combined with any other embodiment or example, and references to "an embodiment," "some embodiments," "one embodiment," etc. are not necessarily mutually exclusive and are intended to indicate that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or example. Such terms as used herein do not necessarily all refer to the same embodiment. Any embodiment may be combined with any other embodiment (inclusive or exclusive) in any manner consistent with the aspects and embodiments disclosed herein.

[0096] Where a technical feature in the drawings, detailed description or any claims is followed by a reference numeral, the reference numeral is included to enhance the intelligibility of the drawings, detailed description and claims. Therefore, neither the reference numerals nor their absence shall have any limiting effect on the scope of any claim element.

[0097] The systems and methods described herein may be embodied in other specific forms without departing from their characteristics. Further descriptions of relative parallel, perpendicular, vertical or other positioning or orientation include variations within + / - 10% or + / - 10 degrees of pure vertical, parallel or perpendicular positioning. Unless otherwise expressly indicated, references to "approximately," "about," "substantially," or other terms of degree include variations within + / - 10% from a given measurement, unit, or range. The coupled elements may be electrically, mechanically, or physically coupled to each other directly or with intervening elements. The scope of the systems and methods described herein is therefore indicated by the appended claims, rather than the foregoing description, and variations that come within the meaning and range of equivalents of the claims are embraced therein.

[0098] The term "coupled" and variations thereof include two components joining together, directly or indirectly. Such joining may be static (e.g., permanent or fixed) or movable (e.g., removable or releasable). Such joining may be achieved by the two components being directly coupled to or coupled to one another, by the two components being coupled to one another using a separate intervening component and any additional intermediate components that are coupled to one another, or by the two components being coupled to one another using an intervening component that is integrally formed with one of the two components as a single, unitary body. If "coupled" or variations thereof are modified by an additional term (e.g., directly coupled), the general definition of "coupled" provided above is modified by the ordinary language meaning of the additional term (e.g., "directly coupled" means joining two components without any separate intervening components), resulting in a narrower definition than the general definition of "coupled" provided above. Such coupling may be mechanical, electrical, or fluidic.

[0099] References to "or" may be interpreted as inclusive, such that any term described using "or" may refer to any of a single, more than one, and all of the described terms. References to "at least one of 'A' and 'B'" may include only 'A', only 'B', and both 'A' and 'B'. Such references used in conjunction with "including" or other open terminology may include additional items.

[0100] Modifications to the described elements and actions may be made without materially departing from the teachings and advantages of the subject matter disclosed herein, such as variations in the dimensions, size, structure, shape, and proportions of the various elements, variations in parameter values, mounting arrangements, use of materials, colors, and orientations. For example, an element shown as integrally formed may be constructed from multiple parts or elements, the positions of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. Other substitutions, modifications, changes, and omissions may also be made in the design, operating conditions, and arrangement of the disclosed elements and actions without departing from the scope of this disclosure.

[0101] References herein to the positions of elements (e.g., "top," "bottom," "upper," "lower") are intended only to describe the orientation of the various elements in the drawings. It should be noted that the orientation of the various elements may differ according to other exemplary embodiments, and such variations are intended to be encompassed by the present disclosure.

Claims

1. A light detection and ranging (LIDAR) system comprising: a laser source configured to generate a beam; as well as A polygon scanner, the polygon scanner comprising: a frame having a first planar frame surface and a second planar frame surface about an axis, and at least one frame portion between the first planar frame surface and the second planar frame surface; and a plurality of reflectors coupled to the frame, each reflector comprising a glass material, a central portion of an inner surface of a first reflector of the plurality of reflectors coupled to the first planar frame surface, and a central portion of an inner surface of a second reflector of the plurality of reflectors coupled to the second planar frame surface, at least one frame portion being spaced apart from the inner surface of the first reflector and bent away from the first planar frame surface, the central portion of the first reflector being coupled to the first planar frame surface by an adhesive having a coefficient of thermal expansion equal to a coefficient of thermal expansion of the first reflector, the first reflector extending further than the first planar frame surface in a direction along the axis, wherein a first edge of the first reflector is adjacent to a second edge of the second reflector, and a gap exists between the first edge and the second edge.

2. The LIDAR system according to claim 1, wherein: Each reflector comprises a polished glass material. 3 . The LIDAR system of claim 1 , further comprising a modulator configured to receive the beam and modulate at least one of a phase or a frequency of the beam to output the modulated beam to the polygon scanner.

4. The LIDAR system according to claim 1, wherein: At least one of the plurality of mirrors has a distortion from 0 nanometers to less than 200 nanometers relative to a plane of the at least one mirror within a temperature range from negative 20 degrees Celsius to 50 degrees Celsius.

5. The LIDAR system according to claim 1, wherein: The frame is configured to rotate about the axis, and the direction is parallel to the axis.

6. The LIDAR system according to claim 1, wherein: The first edge is at a distance from the frame.

7. The LIDAR system according to claim 1, wherein: The first edge and the second edge are angled such that a size of the gap decreases in a direction away from the axis.

8. An autonomous vehicle control system comprising: a laser source configured to generate a first beam; a polygon scanner comprising a frame and a plurality of reflectors coupled to the frame, the frame having a first planar frame surface and a second planar frame surface surrounding an axis, the frame including at least one frame portion between the first planar frame surface and the second planar frame surface, each reflector comprising a glass material, a central portion of an inner surface of a first reflector of the plurality of reflectors being coupled to the first planar frame surface, and a central portion of an inner surface of a second reflector of the plurality of reflectors being coupled to the second planar frame surface, the at least one frame portion being spaced apart from the inner surface of the first reflector and bent away from the first planar frame surface, the central portion of the first reflector being coupled to the first planar frame surface by an adhesive having a thermal expansion coefficient equal to that of the first reflector, the first reflector extending further in a direction along the axis than the first planar frame surface, the polygon scanner being configured to reflect the first beam into a second beam, wherein a first edge of the first reflector is adjacent to a second edge of the second reflector, and a gap is present between the first edge and the second edge; One or more processors configured to: determining at least one of a range to the object or a velocity of the object using a third beam received from at least one of reflection or scattering of the second beam by the object; and Operation of the autonomous vehicle is controlled responsive to the at least one of the range or the speed.

9. The autonomous vehicle control system of claim 8, further comprising a motor configured to rotate the polygon scanner.

10. The autonomous vehicle control system of claim 8, wherein: The one or more processors are configured to determine the range to the object based on times of flight associated with the second beam and the third beam.

11. The autonomous vehicle control system of claim 8, wherein: Each reflector comprises a polished glass material.

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

13. The autonomous vehicle control system of claim 8, wherein: The first reflector is made of a material such that a distortion of the first reflector relative to a plane of the first reflector is from 0 nanometers to less than 200 nanometers within a temperature range from negative twenty degrees Celsius to 50 degrees Celsius.

14. An autonomous vehicle comprising: A LIDAR system, comprising: a laser source configured to generate a first beam; and a polygon scanner comprising a frame and a plurality of reflectors coupled to the frame, the frame having a first planar frame surface surrounding an axis and a second planar frame surface surrounding the axis, the frame including at least one frame portion between the first planar frame surface and the second planar frame surface, each reflector comprising a glass material, a central portion of an inner surface of a first reflector of the plurality of reflectors being coupled to the first planar frame surface, and a central portion of a second reflector of the plurality of reflectors being coupled to the second planar frame surface, the at least one frame portion being spaced apart from the inner surface of the first reflector and bent away from the first planar frame surface, the central portion of the first reflector being coupled to the first planar frame surface by an adhesive having a thermal expansion coefficient equal to that of the first reflector, the first reflector extending further in a direction along the axis than the first planar frame surface, the polygon scanner being configured to reflect the first beam to output a second beam, wherein a first edge of the first reflector is adjacent to a second edge of the second reflector, and a gap is present between the first edge and the second edge; Steering system; braking system; and A vehicle controller comprising one or more processors configured to: determining at least one of a range to the object or a velocity of the object using a third beam received from at least one of reflection or scattering of the second beam by the object; and Operation of the at least one of the steering system and the braking system is controlled responsive to the at least one of the range or the speed.

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