Rotary Compact Optical Ranging System

Abstract

A light ranging system includes: a shaft; a first circuit board assembly including a stator assembly having a plurality of stator elements disposed on a surface of the first circuit board assembly around the shaft; a second circuit board assembly rotatably coupled to the shaft, wherein the second circuit board assembly includes a rotor assembly having a plurality of rotor elements disposed on a surface of the second circuit board assembly around the shaft such that the plurality of rotor elements are aligned with and spaced from the plurality of stator elements; a stator driver circuit disposed on either the second or the first circuit board assembly and configured to provide drive signals to the plurality of stator elements, thereby imparting an electromagnetic force on the plurality of rotor elements to drive rotation of the second circuit board assembly around the shaft; and a light ranging device mechanically coupled to the second circuit board assembly such that the light ranging device rotates with the second circuit board assembly.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims priority to the following patent applications: U.S. Patent Application No. 16 / 209,867, filed December 4, 2018, entitled "Rotating Compact Light Ranging System" ('867 application); U.S. Patent Application No. 16 / 209,869, filed December 4, 2018, entitled "Light Ranging System with Opposing Circuit Boards" ('869 application); U.S. Patent Application No. 16 / 209,875, filed December 4, 2018, entitled "Rotating Light Ranging System with Optical Communication Uplink and Downlink Channels" ('875 application); and U.S. Patent Application No. 16 / 209,879, filed December 4, 2018, entitled "Light Ranging Device with a Multi-element Bulk Lens System" ('879 application). Each of the '867, '869, '875, and '879 applications is hereby incorporated by reference in its entirety for all purposes, and each claims the benefit of U.S. Provisional Patent Application No. 62 / 596,018, filed December 7, 2017, entitled "Compact LIDAR System", which is also hereby incorporated by reference in its entirety for all purposes. BACKGROUND OF THE INVENTION

[0003] Light imaging, detection, and ranging (LIDAR) systems measure the distance to a target by illuminating the target with pulsed lasers and measuring the reflected pulses with sensors. Time-of-flight measurements can then be used to generate a digital 3D representation of the target. LIDAR systems can be used in a variety of applications that require the use of 3D depth images, including archaeology, geography, geology, forestry, mapping, construction, medical imaging, and military applications, among others. Autonomous vehicles can also use LIDAR for obstacle detection and avoidance as well as vehicle navigation.

[0004] Many currently available LIDAR sensor technologies that provide sufficient coverage and resolution for obstacle detection and avoidance in autonomous vehicles are technically complex and expensive to manufacture. Such sensors may thus be too costly to be widely deployed in mass-market cars, trucks, and other vehicles. The overall component cost and manufacturing complexity of a particular type of LIDAR sensor are generally affected by the underlying complexity in the architecture of the LIDAR sensor itself. This problem may be further exacerbated in some modern LIDAR sensors, which are combinations of different internal subsystems, each of which may be very complex on its own, such as optoelectronic systems, electromechanical systems, computer control systems, high-speed communication systems, data processing systems, and so on.

[0005] To achieve the high positional accuracy, long range, and low power consumption that may be important for some modern sensing applications, the stringent technical requirements for each of these subsystems result in architectures and designs that are complex and difficult to build, and often require expensive calibration and alignment procedures before individual LIDAR units are available for consumers. For example, the internal architecture of some LIDAR systems employs one or more large motherboards and large, heavy optical systems that are mounted on a counterweighted structural member, all within a turntable that rotates at a rate of approximately 1,000 RPM. In some of these systems, individual laser emitter / detector pairs are mounted to individual circuit boards. Thus, each emitter board and receiver board may need to be individually mounted to the motherboard, and each emitter / detector pair precisely aligned in a particular direction to ensure that the field of view of each detector overlaps with the field of view of the corresponding emitter of the detector. Due to the above architecture, precision alignment techniques are typically required during assembly to individually align each emitter board and each receiver board.

[0006] When scaling the resolution of the device is desired, the architectures described above become increasingly problematic. Increasing the resolution requires adding more laser emitter / detector pairs, which are also each mounted on their own circuit boards. Thus, linearly scaling the resolution in the case of this type of architecture may result in an exponential increase in manufacturing cost, and may also result in an exponential decrease in reliability, given the excessive number of individual parts and boards involved. Once assembly and alignment are complete, great care must be taken that the precisely aligned multi-board arrangement does not become misaligned due to interference or jostling during shipping or at some other point during the design life of the system.

[0007] In addition to the complexity of alignment and assembly of optical systems, most currently available LIDAR units also have relatively low overall system integration. For example, the control and drive circuits in many currently available LIDAR units are separate modules mounted on custom boards. These custom boards may in turn need to be mounted on a motherboard within the LIDAR unit, or may be mounted elsewhere on a structural element of the LIDAR unit with the aid of one or more mounting brackets. In some cases, each board may have one or more electrical interconnects that need to be routed through one or more internal volume spaces or passages within the housing to ultimately connect to the motherboard.

[0008] For rotating LIDAR systems, the electric motor rotor and / or stator may require additional specialized mounts and interconnects. In addition to power connections, data uplink and downlink lines are required, and they are typically implemented by one or more inductors, capacitors, and / or metal slip ring rotary couplings, which can be difficult to implement and / or result in low data transfer rates. Some systems use metal brushes within the rotary coupling and may thus be unreliable due to the mechanical contact requirements of the brushes within the rotating structure. Other slip ring type connectors may use hazardous substances such as mercury, rendering these types of connectors non-compliant with the Restriction of Hazardous Substances Directive 2002 / 95 / EC (ROHS) and thus not recommended for use, and even prohibited in some jurisdictions.

[0009] Relative to optoelectronic systems, the industry has experienced challenges in incorporating cost-effective single-photon photodetectors such as CMOS-based single-photon avalanche diodes (SPADs), due to their low quantum efficiency in the near-infrared wavelength and their low dynamic range. To improve the quantum efficiency, some SPAD-based detectors use InGaA technology, but such systems are more challenging to integrate in a cost-effective manner compared to CMOS devices. Thus, the external / support circuits associated with SPAD detectors fabricated using InGaAs technology (e.g., quenching circuits that can sense the leading edge of the avalanche current, generate a standard output pulse synchronous with the avalanche buildup, quench the avalanche by reducing the bias voltage back to the breakdown voltage, and then restore the photodiode to the operating level) are typically fabricated separately from the SPAD array in a package external to the SPAD array, for example. Additionally, InGaAs substrates are relatively expensive, and the associated manufacturing processes typically have a lower yield than silicon substrate manufacturing processes, exacerbating the cost increase. To make matters more complex, InGaAs substrates typically need to be effectively cooled to reduce the dark current to an appropriate level, which increases the amount of energy consumed during operation, further increasing cost and complexity.

[0010] Instead of using a SPAD-based detector, many commercially available LIDAR solutions use avalanche photodiodes (APDs). An APD is not a binary detection device, but rather outputs an analog signal (e.g., current) proportional to the intensity of the light incident on the detector, and thus has a high dynamic range. However, an APD must be supported by several additional analog circuits, including (e.g.) analog circuits such as a transimpedance amplifier and / or a differential amplifier, a high-speed A / D converter, one or more digital signal processors (DSPs), etc. Conventional APDs also require a high reverse bias voltage that cannot be achieved with standard CMOS processes. Without mature CMOS, it is difficult to integrate all of this analog circuitry onto a single chip in a compact form factor, and multiple external circuit modules located on a printed circuit board are typically employed, which results in a high cost for these existing units.

[0011] Accordingly, in order to support the growing market for 3D sensing systems, there has been a need for more cost-effective but still high-performance LIDAR systems. Additionally, there has been a need for an improved and more elegant system architecture that enables a streamlined assembly process that can be effectively adopted on a large scale. SUMMARY OF THE INVENTION

[0012] Embodiments of the present disclosure relate to a LIDAR unit that can be used, in particular, for obstacle detection and avoidance in autonomous vehicles. Various embodiments of the present disclosure can address one or more of the problems associated with some currently available LIDAR systems discussed above. Some particular embodiments relate to LIDAR systems that include design features that enable the system to be manufactured inexpensively enough, with sufficient reliability, and with a small enough footprint for use in mass-market automobiles, trucks, and other vehicles.

[0013] In some embodiments, a spin-based optical ranging system according to the present disclosure can include an optical ranging device (e.g., that emits light pulses and detects the reflected pulses) connected to an upper circuit board assembly that rotates about an axis defined by a shaft. The upper circuit board assembly can cooperate with a lower circuit board assembly via respective circuit elements, e.g., to provide power, data, and / or encoded position. Including cooperating wireless circuit elements (e.g., as opposed to external physical connections) on the rotating upper and lower board assemblies can provide a more compact design. Additionally, certain circuit elements (e.g., optical or power) can be positioned in a manner to enable efficient communication and / or increase flux. For example, a wireless power receiver can be provided in a loop at the outer edge of the upper circuit board assembly, thereby maximizing the amount of magnetic flux captured by the inductive loop or maximizing the area available in a capacitive system.

[0014] According to some embodiments, an optical communication subsystem can provide an optical communication channel between a rotating optical ranging device and a base subsystem that does not rotate about a shaft. The optical communication channel can provide fast communication and can provide a compact and inexpensive design. For example, a turret optical communication assembly can be positioned on a rotating assembly to communicate data (e.g., ranging data from an optical ranging device) with a base optical communication assembly. This positioning can alleviate the need for a bulkier communication mechanism. For example, a downlink transmitter can be positioned to transmit optical ranging data via a hollow shaft for rotation. As another example, one or more uplink transmitters of the base subsystem can transmit uplink signals to one or more uplink receivers that rotate on the rotating assembly, such as where these uplink elements are positioned in aligned rings.

[0015] According to some embodiments, the rotation of an upper circuit board assembly can be driven by stator and rotor elements integrated on the upper and lower circuit boards, thereby making the optical ranging system compact. For example, the upper circuit board assembly can include a plurality of rotor elements symmetrically arranged around a rotating shaft, and the lower circuit board assembly can include a plurality of stator elements symmetrically arranged around the shaft. A driver circuit can drive the stator elements. Incorporating such rotor and stator elements onto the circuit board itself provides various advantages over products that use bulkier motors (e.g., stepper motors, brushed motors, or non-integrated brushless motors).

[0016] According to some embodiments, an optical ranging system includes: a shaft having a longitudinal axis; a first circuit board assembly including a stator assembly having a plurality of stator elements arranged on a surface of the first circuit board assembly around the shaft; a second circuit board assembly rotatably coupled to the shaft and spaced apart and opposed to the first circuit board assembly, wherein the second circuit board assembly includes a rotor assembly having a plurality of rotor elements arranged on a surface of the second circuit board assembly around the shaft such that the plurality of rotor elements are aligned and spaced apart from the plurality of stator elements; a stator driver circuit disposed on either the second or the first circuit board assembly and configured to provide drive signals to the plurality of stator elements, thereby imparting an electromagnetic force on the plurality of rotor elements to drive rotation of the second circuit board assembly about the longitudinal axis of the shaft; and an optical ranging device mechanically coupled to the second circuit board assembly such that the optical ranging device rotates with the second circuit board assembly.

[0017] In some embodiments, an optical ranging system includes: a shaft; a first circuit board assembly including a stator assembly having a plurality of stator elements disposed on a surface of the first circuit board assembly around the shaft; a second circuit board assembly rotatably coupled to the shaft, wherein the second circuit board assembly includes a rotor assembly having a plurality of rotor elements disposed on a surface of the second circuit board assembly around the shaft such that the plurality of rotor elements are aligned with and spaced from the plurality of stator elements; an optical ranging device coupled to rotate with the second circuit board assembly, the optical ranging device including a light source configured to transmit light pulses to an object in the surrounding environment, and a detector circuit configured to detect a reflected portion of the light pulses reflected from the object in the surrounding environment and calculate ranging data based on the reflected portion of the light pulses; and a stator driver circuit disposed on either the second or the first circuit board assembly and configured to provide drive signals to the plurality of stator elements, thereby imparting an electromagnetic force on the plurality of rotor elements to drive rotation of the second circuit board assembly around the shaft.

[0018] In some embodiments, an optical ranging system includes: a fixed housing having an optically transparent window and a base; a hollow shaft disposed within the housing; a bearing system coupled to the hollow shaft; a first circuit board assembly disposed within the housing and parallel to a first plane perpendicular to the hollow shaft, the first circuit board assembly including a stator assembly having a plurality of evenly spaced stator elements disposed annularly around the shaft on a surface of the first circuit board assembly; a second circuit board assembly disposed within the housing, parallel to the first plane and rotatably coupled to the shaft by the bearing system, wherein the second circuit board assembly includes a rotor assembly having a plurality of evenly spaced rotor elements disposed annularly around the shaft on a surface of the second circuit board assembly such that the plurality of rotor elements are aligned with and spaced from the plurality of stator elements; an optical ranging device coupled to rotate within the fixed housing with the second circuit board assembly, the optical ranging device including a light source configured to transmit light pulses to an object in the surrounding environment via the window, and a detector circuit configured to detect a reflected portion of the light pulses received via the window that are reflected from the object in the surrounding environment and calculate ranging data based on the reflected portion of the light pulses; and a stator driver circuit disposed on either the second or the first circuit board assembly and configured to provide drive signals to the plurality of stator elements, thereby imparting an electromagnetic force on the plurality of rotor elements to drive rotation of the second circuit board assembly and the optical ranging device around the shaft.

[0019] According to some embodiments, a light ranging system includes: a housing; a shaft defining a rotation axis; a first circuit board assembly disposed within the housing in a fixed relationship and coupled to the housing such that the first circuit board assembly is aligned along a first plane perpendicular to the rotation axis, the first circuit board assembly including a plurality of first circuit elements disposed on the first circuit board; a second circuit board assembly spaced from the first circuit board assembly within the housing in a second plane parallel to the first plane and rotatably coupled to the shaft such that the second circuit board assembly rotates about the rotation axis, the second circuit board assembly including a plurality of second circuit elements disposed on the second circuit board and aligned with at least one of the first plurality of circuit elements and configured to operate in a wireless cooperative manner with at least one of the first plurality of circuit elements; and a light ranging device electrically connected and coupled to rotate with the second circuit board assembly, the light ranging device configured to transmit light pulses to an object in the surrounding environment, detect a reflected portion of the light pulses reflected from the object in the surrounding environment, and calculate ranging data based on the reflected portion of the light pulses.

[0020] In some embodiments, a light ranging system includes: a housing having an optically transparent window; a shaft defining a rotation axis passing through the housing; a first circuit board assembly disposed within the housing and fixedly coupled to the housing and aligned perpendicular to the rotation axis; a second circuit board assembly disposed within the housing and spaced from and in an opposing relationship to the first circuit assembly, the second circuit board assembly rotatably coupled to the shaft; a light ranging device coupled in a fixed relationship to the second circuit board assembly such that the light ranging device rotates about the shaft with the second circuit board assembly; a ring encoder including a ring encoder strip mounted on one of the first or second circuit boards and an encoder reader mounted on the other of the first or second circuit boards in a position facing and opposing the ring encoder strip; a wireless communication system including a first ring wireless communication component mounted to the first circuit board and a second ring wireless communication component mounted to the second circuit board in a position facing and opposing the first ring wireless communication component; and a ring wireless power transfer system including a ring wireless power transmitter mounted to the first circuit board and a ring wireless power receiver mounted to the second circuit board in a position facing and opposing the ring wireless power transmitter.

[0021] In some embodiments, a light ranging system includes: a housing having an optically transparent window; a shaft defining a rotational axis passing through the housing; a first circuit board assembly disposed within the housing and fixedly coupled to the housing and aligned perpendicular to the rotational axis; a second circuit board assembly disposed within the housing and spaced apart from and in a relative relationship with the first circuit assembly, the second circuit board assembly being rotatably coupled to the shaft; a light ranging device mounted to the second circuit board assembly such that the light ranging device rotates about the shaft with the second circuit board assembly, the light ranging device being configured to transmit light pulses to an object in the surrounding environment, detect a reflected portion of the light pulses reflected from the object in the surrounding environment, and calculate ranging data based on the reflected portion of the light pulses; a ring encoder including a ring encoder strip mounted on one of the first or second circuit boards and an encoder reader mounted on the other of the first or second circuit boards at a position facing and opposite to the ring encoder strip; a wireless communication system including a first ring wireless communication component mounted to the first circuit board and a second ring wireless communication component mounted to the second circuit board at a position facing and opposite to the first ring wireless communication component; an electric motor including a stator assembly including a plurality of stator elements disposed on a surface of the first circuit board assembly around the shaft and a rotor assembly including a plurality of rotor elements disposed on a surface of the second circuit board assembly around the shaft such that the plurality of rotor elements are disposed at a position facing and opposite to the plurality of stator elements; a stator driver circuit disposed on either the second or first circuit board assembly and configured to provide drive signals to the plurality of stator elements, thereby imparting an electromagnetic force on the plurality of rotor elements to drive rotation of the second circuit board assembly about the shaft; and a ring wireless power transfer system including a ring wireless power transmitter mounted to the first circuit board and a ring wireless power receiver mounted to the second circuit board at a position facing and opposite to the ring wireless power transmitter.

[0022] According to some embodiments, a light ranging system includes: a shaft having a longitudinal axis; a light ranging device configured to rotate about the longitudinal axis of the shaft, the light ranging device including a light source configured to transmit light pulses to an object in the surrounding environment and a detector circuit configured to detect a reflected portion of the light pulses reflected from the object in the surrounding environment and calculate ranging data based on the reflected portion of the light pulses; a base subsystem that does not rotate about the shaft; and an optical communication subsystem configured to provide an optical communication channel between the base subsystem and the light ranging device, the optical communication subsystem including one or more turret optical communication components connected to the detector circuit and one or more base optical communication components connected to the base subsystem.

[0023] In some embodiments, a light ranging system includes: a housing having an optically transparent window; a hollow shaft having a longitudinal axis disposed within the housing; a light ranging device disposed within the housing and configured to rotate about the longitudinal axis of the shaft, the light ranging device including a light source configured to transmit light pulses through the optically transparent window to an object in the surrounding environment, and a detector circuit configured to detect a reflected portion of the light pulses that pass through the optically transparent window and are reflected from the object in the surrounding environment and calculate ranging data based on the reflected portion of the light pulses; a base subsystem disposed within the housing and not rotating about the shaft; and an optical communication subsystem disposed within the housing and configured to provide an optical communication channel between the base subsystem and the light ranging device, the optical communication subsystem including a first optical channel disposed within the hollow shaft and a second optical channel disposed annularly outside the hollow shaft.

[0024] In some embodiments, a light ranging system includes: a housing having an optically transparent window; a hollow shaft having a longitudinal axis disposed within the housing; a light ranging device disposed within the housing and configured to rotate about the longitudinal axis of the shaft, the light ranging device including a light source configured to transmit light pulses through the optically transparent window to an object in the surrounding environment, and a detector circuit configured to detect a reflected portion of the light pulses that pass through the optically transparent window and are reflected from the object in the surrounding environment and calculate ranging data based on the reflected portion of the light pulses; a base subsystem disposed within the housing and not rotating about the shaft; a first optical communication channel configured to optically transmit data between the light ranging device and the base subsystem via the hollow shaft, the first optical communication channel including a first optical component coupled to a circuit that is coupled to rotate with the light ranging device and a second optical component coupled to a circuit disposed on the base subsystem; and a second annular optical communication channel disposed around the hollow shaft and configured to optically transmit data between the light ranging device and the base subsystem, the annular optical communication channel including a first annular optical component coupled to a circuit that is coupled to rotate with the light ranging device and a second annular optical component coupled to a circuit disposed on the base subsystem.

[0025] According to some embodiments, a light ranging device may include a light emitting module and a light sensing module. The light emitting module may include a light source configured to transmit light pulses into an object in the surrounding environment. The light sensing module may include: a lens housing; a body lens system coupled to the lens housing and configured to receive light from the surrounding environment and focus the received light onto a focal plane, the body lens system including a first lens, a second lens, and a third lens mounted in the lens housing; wherein the first lens, the second lens, or the first lens and the second lens are plastic; and wherein the third lens is glass; a photoelectric sensor array configured to receive light from the body lens system and detect a reflected portion of the light pulse reflected from an object in the surrounding environment; and a mount that mechanically couples the lens housing to the photoelectric sensor array, wherein the lens housing, the body lens system, and the mount are configured to passively focus light from the body lens system onto the photoelectric sensor array within a certain temperature range. In some cases, the lens housing, the body lens system, and the mount are configured to match the focal length of the lens system with the coefficient of thermal expansion of the lens housing and with the coefficient of thermal expansion of the mount according to temperature, such that light is passively focused onto the photoelectric sensor array within a temperature range, for example, from -5 degrees Celsius to 70 degrees Celsius.

[0026] In some embodiments, a light ranging system includes a housing having an optically transparent window, a light ranging device disposed within the housing, and a circuit configured to calculate ranging data. The light ranging device may include: an optical transmitter including a body transmitter lens system and a plurality of transmitter channels, each channel including a light emitter configured to generate a narrowband light pulse and transmit the narrowband light pulse through the body transmitter optics and through the optically transparent window into a field external to the light ranging system; and a light receiver including a body receiver lens system, a lens housing, and a plurality of micro-optics receiver channels, each micro-optics channel including a pore coinciding with the focal plane of the body receiver optics, a collimating lens behind the pore, an optical filter behind the collimating lens, and a photoelectric sensor that responds to incident photons passing through the pore into the collimating lens and through the filter. The body receiver lens system may include a first lens, a second lens, and a third lens mounted in the lens housing; wherein the first lens, the second lens, or the first lens and the second lens are plastic; the third lens is glass; and the coefficient of thermal expansion (CTE) of the lens housing matches the body receiver lens system within a certain temperature range such that the focal plane is stable relative to each photoelectric sensor in the plurality of micro-optics receiver channels within the temperature range. In some cases, the temperature range is from 20 degrees Celsius to 70 degrees Celsius, and in some cases, the temperature range is from -5 degrees Celsius to 70 degrees Celsius.

[0027] In some embodiments, an image sensing device is provided. The image sensing device may include a lens housing; a body lens system mechanically coupled to the lens housing and configured to receive light from the surrounding environment and focus the received light onto a focal plane. The body lens system may include a first lens, a second lens, and a third lens mounted in the lens housing, wherein the first lens, the second lens, or the first and second lenses are plastic, and wherein the third lens is glass. The image sensing device may further include a photoelectric sensor array configured to receive light from the body lens system, and a mounting member that mechanically couples the lens housing to the photoelectric sensor array. The coefficient of thermal expansion (CTE) of the lens housing may match that of the body lens system within a certain temperature range such that the focal plane is stable relative to the photoelectric sensor array within the temperature range. In some cases, the temperature range is from 20 degrees Celsius to 70 degrees Celsius, and in some cases, the temperature range is from -5 degrees Celsius to 70 degrees Celsius. Also, in some embodiments, the CTE of the mounting member matches the CTE of the lens housing.

[0028] *

[0029] These and other embodiments of the present invention are described in detail below. In addition, other aspects and advantages of the various embodiments of the present disclosure will become apparent from the following detailed description taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the described embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figures 1A - 1B A rotational light ranging system and a non-rotational solid-state light ranging system that can be used in automotive applications are shown respectively according to some embodiments;

[0031] Figures 2A - 2B High-level block diagrams of rotational and solid-state LIDAR systems are shown respectively according to some embodiments;

[0032] Figure 3 Shown is a more detailed block diagram of a rotational LIDAR system 300 according to some embodiments similar to the embodiments described above with reference to Figure 2A A more detailed block diagram of a rotational LIDAR system 300 according to some embodiments similar to the embodiments described above;

[0033] FIG. 4 shows an illustrative example of a light transmission and detection process for a light ranging system according to some embodiments, focusing on the transmitter array and the sensor array that form the arrangement of the transmitter-sensor channels, as introduced above with reference to FIG. 2;

[0034] Figures 5A - 5B A rotational LIDAR system 500 is shown according to one or more embodiments;

[0035] Figures 6A - 6C A cross-sectional view of a LIDAR system is shown according to one or more embodiments;

[0036] Figure 6D Shows a top view of a stator plate according to one or more embodiments;

[0037] Figure 6E Shows a bottom view of a rotor plate according to one or more embodiments;

[0038] Figure 6F Is a simplified cross-sectional view of a part of a multi-coil wireless power receiver positioned within an annular ferrite channel according to some embodiments;

[0039] Figure 7 Shows an exploded view of a lower circuit board assembly according to certain embodiments to illustrate the assembly process of a compact LIDAR system;

[0040] Figure 8A And 8B Shows an exploded view of a LIDAR system according to some embodiments;

[0041] Figures 9A - 9C Respectively show a perspective view, a front view, and a scaled front view of a light ranging device 900 according to certain embodiments;

[0042] Figure 10 Shows an optical block diagram of a light ranging device 1000 according to certain embodiments, which shows the optical systems of both the Rx module 1001 and the Tx module 1003;

[0043] Figure 11A Shows a top view of a micro-optics package according to certain embodiments;

[0044] Figure 11B Shows a cross-section of a single micro-optics receiver channel according to some embodiments;

[0045] Figures 12A - 12B Shows a top view of a SPAD-based detector according to some embodiments;

[0046] Figure 13A And B show a simplified top view and a side view of a VCSEL chip transmitter according to some embodiments;

[0047] Figure 14 Depicts a simplified schematic diagram of an embodiment of a LIDAR body optical system;

[0048] Figure 15A 、 15B And 15C depict an embodiment of a body optical lens assembly;

[0049] Figures 16A - 16E Depicts various views of an embodiment of a lens assembly;

[0050] Figures 17A - 17D Cross-section of an embodiment of a lens depicting a lens assembly; and

[0051] Figure 18 Depicts an embodiment of a lens assembly having three lenses.

[0052] The term

[0053] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. However, the following definitions are provided to facilitate understanding of certain terms that are frequently used and are not intended to limit the scope of the present disclosure. The abbreviations used herein have their conventional meanings within the relevant technical field.

[0054] The term ranging data may refer to any data that can be transmitted from a laser ranging device such as a turntable assembly of a rotating LIDAR system. Examples of ranging data include range information (e.g., the distance to a given target point at a specific angle (azimuth and / or elevation)), range-rate or velocity information (e.g., the derivative of the ranging data with respect to time), and operating information (e.g., the signal-to-noise ratio (SNR) or signal strength returned, target reflectivity, ambient NIR level from each pixel field of view, diagnostic information including temperature, voltage level, etc.). In some embodiments, the ranging data may include RGB information from an RGB camera located in the turntable, such as a high-speed readout camera, such as a line scan camera or a thermal imager.

[0055] The term turntable may refer to the rotating part or portion of a rotating LIDAR system. The turntable assembly includes any rotating component or circuit board in the turntable portion of the LIDAR system, and may include one or more components located in the optical ranging device and / or one or more components located on the rotating circuit board of the rotary actuator.

[0056] In the context of a rotating LIDAR system (sometimes referred to herein as a "spinning LIDAR system"), the term base may refer to the non-rotating part or non-rotating portion of the rotating LIDAR system. The base assembly includes any non-rotating component or circuit board in the base portion of the LIDAR system, and may include one or more components located in the base assembly and / or one or more components located on the non-rotating circuit board of the rotary actuator.

[0057] The terms upper and lower refer to the positioning or relative positioning of components along the axis of rotation of the LIDAR system. In some embodiments, the upper component, also referred to as the turntable assembly, is located on the turntable of the LIDAR system, while the lower component, also referred to as the base assembly, is located on the base of the LIDAR system.

[0058] The term "ring" includes not only circular shapes, but also slightly non-circular shapes (e.g., oval), and is circumferentially arranged around a central axis, including perturbations or oscillations (e.g., wavy) at the circumference.

[0059] One or more shapes referred to as symmetric can include both perfectly symmetric shapes and shapes that are generally but not completely symmetric. The arrangements of the electronic components described herein can operate most effectively in symmetric configurations; however, the term "symmetric" does not exclude those configurations that are slightly asymmetric or have a slight deviation from symmetry, even if those configurations do not result in the optimal operating configuration.

[0060] The term "parallel" is not limited to being perfectly parallel, but also includes those geometric arrangements and configurations that are generally parallel due to manufacturing variations. For example, two elements referred to as parallel in this document can have an angle between -5 and 5 degrees or between -1 and 1 degree between the two elements, depending on the manufacturing tolerances employed.

[0061] The term "perpendicular" is not limited to being perfectly perpendicular, but also includes those geometric arrangements and configurations that are generally perpendicular due to manufacturing variations. For example, two elements referred to as perpendicular in this document can have an angle between 85 and 95 degrees between the two elements.

[0062] The term "photoelectric sensor" (or simply "sensor") refers to a sensor that can convert light into an electrical signal (e.g., an analog electrical signal or a binary electrical signal). An avalanche photodiode (APD) is an example of a photoelectric sensor. A single photoelectric sensor can include multiple smaller "photoelectric detectors". Thus, multiple single-photon avalanche diodes (SPADs) can be another example of a photoelectric sensor, where each individual SPAD among the multiple SPADs (e.g., each SPAD in an SPAD array) can be referred to as a photoelectric detector. The term "sensor array" can sometimes refer to a sensor chip that includes an array of multiple sensors. Additionally, the term "pixel" can sometimes be used interchangeably with photoelectric sensor or sensor.

[0063] The term "transmitter" can refer to a structure that includes one or more optical transmission elements such as LEDs, lasers, VCSELs, etc. The term "transmitter" can also include a transmitter chip that includes a transmitter array (sometimes referred to as a transmitter array).

[0064] The term volumetric optic refers to a single lens and / or lens assembly that includes one or more macro-sized optics, e.g., optics having a diameter on the order of centimeters or greater, such as those used in commercially available camera lenses and microscope lenses. In the present disclosure, the term volumetric optic is contrasted with the term micro-optic, which refers to an optical element or an array of optical elements having an individual element diameter on the order of a few microns to a few millimeters or less. Generally speaking, a micro-optic can modify light in different ways for different emitters and / or different detectors of an emitter array or a detector array, while a volumetric optic modifies light for the entire array.

[0065] As used herein, the term image-space telecentric optical module refers to an optical system (volumetric or otherwise) in which, at an image plane, all (or substantially all) chief rays from within the aperture of a lens "go straight" or impinge on the image plane at a zero angle of incidence within a specified tolerance (e.g., + / - 2 degrees). Detailed Description

[0066] According to certain embodiments, the methods and systems disclosed herein relate to a compact light ranging and detection (LIDAR) system, and a method of assembling a compact LIDAR system. The LIDAR system can include a modular light ranging device and an optionally highly compact and integrated rotary actuator. The modular light ranging device can operate as a stand-alone non-rotating solid-state LIDAR or, when connected to the integrated rotary actuator, can operate as part of a turret of a rotating LIDAR. The light ranging device can include a light transmission module (sometimes referred to as a "light emission module") for illuminating an object in a field surrounding the light ranging module, and also include a light sensing module for sensing a reflected or scattered portion of the illumination light pulse for use in calculating a 3D depth image. The light ranging module can also include a detector chip (e.g., a CMOS chip) that includes an array of photosensors, each of which can be, for example, a SPAD array.

[0067] In some embodiments, the rotary actuator includes an upper circuit board assembly (also referred to herein as a turntable, or a rotary circuit board assembly) and a base circuit board assembly (also referred to herein as a stationary circuit board assembly). The various circuit boards of the rotary actuator can be highly integrated in the sense that many of the functional and / or supporting electronic and optical components of the LIDAR system can be directly mounted to one or more of the boards of the rotary actuator. For example, a base controller of the LIDAR system that can control the various emission parameters of the light transmission module can be mounted on a board of the base circuit board assembly of the rotary actuator. Additionally, power can be provided to the light ranging module by means of a wireless power transfer system that is also integrated onto the boards of the rotary actuator. Communication between the base controller and the light ranging module (and vice versa) can be enabled by means of an optical uplink channel and an optical downlink channel, where the electrical and optical components that support the optical uplink / downlink channels are also integrated onto one or more of the circuit boards of the rotary actuator.

[0068] In some embodiments, these same boards include an electric motor assembly integrated onto one or more surfaces of the upper and lower circuit board assemblies of the rotary actuator. For example, an electric motor stator can be directly bonded to the surface of the lower circuit board assembly of the rotary actuator together with other electrical components such as a group of an optical uplink transmitter, an optical downlink receiver, and a wireless power transmitter. Similarly, an electric motor rotor can be directly bonded to the surface of the upper circuit board assembly of the rotary actuator together with other electrical components such as a group of an optical uplink receiver, an optical downlink transmitter, an optical or magnetic rotary encoder reader, and a wireless power receiver.

[0069] In some embodiments, the upper circuit board assembly can include one or more connectors that are also bonded to the surface of the upper circuit board assembly to connect the light ranging module to the upper circuit board assembly. Additionally, the rotary actuator can further include additional computing resources, one or more FPGAs, ASICs, microprocessors, etc., which can be used by the light ranging module to perform data processing on the acquired data.

[0070] Given the high degree of system integration in the compact LIDAR disclosed herein, a fully operational system can be assembled by simply attaching the light ranging module to the rotary actuator. There is no need for a separate electric motor module, a separate communication module, a separate power module, etc.

[0071] In some embodiments, the architecture of the rotary actuator is adapted to an optimal assembly method. For example, the architecture of the system may be such that electrical components including a communication component, an electric motor component, and a wireless power component are arranged circumferentially and concentrically about a central axis of the system, and even coaxially with the axis of the system. The central axis may also be collinear with the axis of rotation of an upper circuit board assembly or turntable. One or more plates of the rotary actuator may include a central hole configured to receive a shaft that may be attached (directly or indirectly) to a lower portion of a fixed housing or a substrate. In some embodiments, the shaft defines the axis of rotation of the system, and one or more bearings attached thereto provide rotational movement of the upper circuit board assembly relative to the lower circuit board assembly.

[0072] Given the above architecture, in some embodiments the assembly of the rotary actuator can be simplified to lowering successive plates into place on the shaft. Since subgroups of electrical components (such as a communication component, an electric motor component, and a wireless power component) are arranged circumferentially about the central axis of the system, these systems can operate effectively once assembled without the need for complex alignment procedures.

[0073] In some embodiments, the system employs a thermal-stabilized image space telecentric optics module used within an optical transmission module or an optical sensing module or both. The thermal-stabilized image space telecentric optics module can be engineered to have an image plane that is stable in space relative to a transmitter or sensor chip that includes an array of transmitters and / or sensors of the optical transmission module or the optical sensing module, respectively. The coefficients of thermal expansion of the lens housing and the optical elements within the lens housing, as well as the refractive index change with respect to temperature, can be selected to achieve a thermally stable image plane. In various embodiments, individual optics in the optical system can be glass and / or plastic to provide an economical but thermally stable design.

[0074] A modular optical ranging device according to some embodiments of the present disclosure includes a set of vertical cavity surface emitting lasers (VCSELs) as an illumination source to emit radiation pulses into a field, and includes an array of single photon avalanche diode (SPAD) detectors as a set of pixels (photoelectric sensors) to detect radiation reflected or scattered from surfaces in the field. As stated above, compared to APDs used in some currently available LIDAR sensors, SPADs have a relatively low dynamic range. The inherently low dynamic range of SPADs is in part attributable to the physics of how SPADs detect photons - they are so-called Geiger mode devices that produce a binary electrical signal (photon detected or not detected) in the form of an avalanche current pulse for each photon detection event. Using VCSELs as emitters and SPADs as detectors enables multiple measurements to be made simultaneously (i.e., the VCSEL emitters can be fired simultaneously), and also enables the set of emitters and the set of photoelectric sensors to be fabricated using standard CMOS processes on a single chip, thus greatly simplifying the manufacturing and assembly processes. However, using VCSELs and SPADs in certain embodiments presents challenges, which various embodiments of the present invention overcome. For example, VCSELs are far less powerful than lasers used in some currently available LIDAR sensors, and SPADs are far less efficient than detectors used in some LIDAR sensors. To address these challenges, as well as challenges arising from firing multiple emitters simultaneously, certain embodiments of the present disclosure may include optical components for enhancing the brightness of the VCSEL emitters and various optical components (e.g., lenses, filters, and pore layers) that can work in concert with multiple SPAD arrays, each array corresponding to a different photoelectric sensor, as described herein.

[0075] I. Exemplary Automotive LIDAR Systems

[0076] Figures 1A - 1B Fig. shows an automotive optical ranging device according to some embodiments, also referred to herein as a LIDAR system. The automotive application of the LIDAR system is selected here for illustrative purposes only, and the sensors described herein can be employed in other types of vehicles such as ships, airplanes, trains, etc., as well as in a variety of other applications where 3D depth images are useful, such as medical imaging, geodesy, mapping, archaeology, geography, geology, geomorphology, seismology, forestry, atmospheric physics, laser guidance, airborne laser swath mapping (ALSM), and laser altimetry. According to some embodiments, a LIDAR system such as scanning LIDAR system 100 and / or solid-state LIDAR system 120 can be mounted on the roof of vehicle 105, as Figure 1A and 1Bas shown. In other embodiments, one or more LIDAR sensors may be mounted at other locations on the vehicle, including (but not limited to) the front or rear of the vehicle, the sides of the vehicle, and / or the corners of the vehicle.

[0077] Figure 1A The scanning LIDAR system 100 shown in may employ a scanning architecture in which the orientation of the LIDAR light transmission module 102 (e.g., a light source for emitting laser pulses) and / or the light sensing module 104 (e.g., a detector circuit for detecting reflected pulses to determine the distance to an object) may be scanned around one or more fields of view 110 in an external field or a scene outside the vehicle 105. In the case of a scanning architecture, the emitted light 112 may be scanned over the surrounding environment as shown. For example, the output beam of one or more light sources (e.g., an infrared or near-infrared pulsed IR laser, not shown) located in the scanning LIDAR system 100 may be scanned (e.g., rotated) to illuminate the scene around the vehicle. In some embodiments, the scanning represented by the rotating arrow 115 may be implemented by mechanical means, such as by mounting the light emitter to a rotating column or platform. In some embodiments, the rotation may be implemented via other mechanical means, such as by using a galvanometer. Chip-based steering techniques may also be employed, such as by using a microchip employing one or more MEMS-based reflectors, such as a digital micromirror (DMD) device, a digital light processing (DLP) device, etc. In some embodiments, the scanning may be achieved via non-mechanical means, such as by using an electronic signal to steer one or more optical phased arrays.

[0078] For a fixed architecture, such as Figure 1B the solid-state LIDAR system 120 shown in, one or more solid-state LIDAR subsystems (e.g., the light transmission module 122 and the light sensing module 124) may be mounted to the vehicle 105. Each solid-state LIDAR unit may face a different direction (with partially overlapping and / or non-overlapping fields of view between the units) in order to capture a composite field of view that is larger than the field of view that each unit alone is capable of capturing.

[0079] In either a rotating or a fixed architecture, an object in the scene may reflect a portion of the light pulses emitted from the LIDAR light source. One or more of the reflected portions then travel back to the LIDAR system and may be detected by the detector circuit. For example, the reflected portion 114 may be detected by the detector circuit 104. The light transmission module may be disposed in the same housing as the light sensing module. Aspects of the scanning system and the fixed system are not mutually exclusive and may thus be used in combination. For example, Figure 1BIndividual LIDAR subsystems 122 and 124 therein may employ steerable transmitters such as MEMS galvanometers, or the entire composite unit may be rotated via mechanical means to scan the entire scene in front of the LIDAR system, e.g., from field of view 130 to field of view 132.

[0080] Figures 2A - 2B Advanced block diagrams of a rotating LIDAR system 200 and a stationary solid-state LIDAR system 230 according to some embodiments are shown, respectively. Both systems employ a light ranging device 210 that includes a light transmission module 212 and a light sensing module 214. The light transmission and sensing modules 212 and 214 may each separately include bulk optics 215 positioned at the input / output of the sensing and transmission modules, such as a multi-element lens assembly. The light transmission module 212 may further include a micro-optics array and an optional notch filter element (not shown) positioned between the bulk optics 215 and the light emitter circuit 216. In some embodiments, the light emitter circuit 216 includes a chip-level array of light sources, such as an array of vertical cavity surface emitting lasers (VCSELs) on an indium gallium arsenide (InGaAs) substrate. The light sensing module 214 may also include a micro-optics array and a notch filter element (not shown) positioned between the bulk optics 215 and the light detector circuit 218. In some embodiments, the light detector circuit 218 may include a chip-level array of photon detectors, such as an array of single photon avalanche diodes (SPADs) fabricated in CMOS technology. Other detector technologies may also be employed, such as avalanche photodiodes, CCD image sensors, CMOS photodiode image sensors, cavity-enhanced photodetectors, surface-enhanced photodetectors, etc.

[0081] Steering Figure 2A , in the rotating LIDAR system 200, the light ranging device 210 may be electrically connected to a turntable circuit board assembly 222 (also referred to herein as an upper circuit board assembly or a ranging circuit board assembly). The circuit board assembly 222 may be considered ranging to the extent that it is connected to the light ranging device 210. As described in more detail below in Figure 3 , the turntable circuit board assembly 222 may include several circuit elements, including one or more processors and memories. For example, the turntable circuit board assembly 222 may include a field programmable gate array (FPGA) and / or one or more application specific integrated circuits (ASICs) adapted to provide specific LIDAR functionality. In some embodiments, the light ranging device 210 may be hardwired to the turntable circuit board assembly 222 via a multi-pin electrical connector, or may be connected to the turntable circuit board assembly 222 wirelessly, e.g., via a communication channel employing an optical or RF connection.

[0082] The turntable circuit board assembly 222 can be disposed directly above the base circuit board assembly 226. In some embodiments, the base circuit board assembly 226 can wirelessly transmit power to the turntable circuit board assembly 222 to power, for example, the optical ranging device 210 and any other associated circuitry (e.g., ASIC, FPGA, communication circuitry, etc.). Additionally, optical, inductive, and / or capacitive communication channels can connect the base circuit board assembly 226 to the turntable circuit board assembly 222, thereby allowing the optical ranging device 210 to be controlled via non-contact data transfer from the base circuit board assembly.

[0083] In Figure 2A the embodiment shown, the turntable circuit board assembly 222 is rotatably coupled to the base circuit board assembly 226 via a rotary coupler 224. The rotary coupler 224 enables the optical ranging device 210 and the turntable circuit board assembly 222 to rotate a full 360 degrees within the housing 220 of the LIDAR system 200. The rotation of the optical ranging device 210 allows the system to acquire data for constructing a full 360-degree field of view 3D map of the volume surrounding the device. In some embodiments, the base circuit board assembly 226 can be coupled to the housing 220, for example, by means of a mechanical bracket and screws (not shown), such that the base circuit board assembly 226 remains fixed and does not rotate relative to the housing 220. The housing 220 can be a waterproof housing that protects the optical ranging device 210 and other internal components of the LIDAR system 200 from moisture and various factors in the operating environment of the LIDAR system 200.

[0084] The rotary coupler 224 can be implemented in a number of different ways in various embodiments. For example, some embodiments can employ a shaft and bearing structure. In some embodiments, the rotary coupler 224 also includes one or more components of a rotary actuator that not only allows rotational movement but also drives the rotational movement of the turntable circuit board assembly 222. For example, an electric motor rotor assembly including an arrangement of rotor elements (e.g., permanent magnets) can be directly integrated into the turntable circuit board assembly 222, and an electric motor stator assembly including an arrangement of stator elements (e.g., solenoid coils) can be directly integrated into the base circuit board assembly 226. In such embodiments where one or more rotary actuation components are integrated into the base circuit board assembly 226 and / or the turntable circuit board assembly 222, a separate module for rotary actuation is no longer required. Thus, embodiments of the LIDAR systems disclosed herein can have a more compact form factor and a much simplified assembly process compared to spinning LIDAR systems that employ separate electric motor modules.

[0085] Figure 2B is a simplified block diagram of a stationary solid-state LIDAR system 230 according to some embodiments. Similar to Figure 2AThe rotational LIDAR system 200 shown in [FIGURE REFERENCE] and the fixed solid-state LIDAR system 230 includes a light ranging device 210 housed within a waterproof housing 240. The light ranging device 210 can be directly connected to a base circuit board assembly 232 within the housing 240. Since the system 230 does not rotate the light ranging device 210, there is no need for a separate rotary turret circuit board assembly or rotary coupler. Accordingly, circuitry previously distributed between the turret circuit board assembly 222 and the base circuit board assembly 226 can be fully integrated into a single base circuit board assembly 232 and / or shared between circuitry associated with the light sensing module 214 and / or the transmission module 212.

[0086] In some embodiments, for Figures 2A - 2B any of the embodiments shown in [FIGURE REFERENCE], the hardware and software / firmware for performing one or more LIDAR-specific operations (e.g., photon time series accumulation, followed by peak detection and ranging data calculation and output) can be incorporated into the circuitry of one or more of the light ranging device 210 and / or circuit board assemblies (e.g., the turret circuit board assembly 222 and / or the base circuit board assembly 226 for the LIDAR system 200, or the base circuit board assembly 232 for the LIDAR system 230). For example, in some embodiments, the light detector circuit 218 can also include an ASIC integrated onto the same substrate as the SPAD array. In this case, the light ranging device 210 is modular in the sense that reprogramming / reconfiguration of the software / firmware can allow the light ranging device 210 to operate as part of a rotational LIDAR system (such as Figure 2A the LIDAR system 200 shown in [FIGURE REFERENCE]) or as a stand-alone solid-state LIDAR system (such as Figure 2B the LIDAR system 230 shown in [FIGURE REFERENCE]). As already mentioned above, circuitry (e.g., MEMS, DMD, optical phased arrays, etc.) can be employed that will also allow beam steering without a mechanical rotation actuator. Accordingly, the modular design of the systems disclosed herein results in a highly adaptable system that can meet user requirements without the expensive and time-consuming re-design of the overall hardware and mechanical architecture.

[0087] II. Detailed Block Diagrams

[0088] Figure 3 Shown in accordance with a similar to that referenced above Figure 2AA more detailed block diagram of the rotational LIDAR system 300 of some embodiments of the described embodiments. More specifically, the rotational LIDAR system 300 may optionally employ a rotational actuator having wireless data and power transmission and reception capabilities. In some embodiments, the rotational actuator includes a rotor integrated on the surface of a rotating circuit board and a stator integrated on the surface of a fixed circuit board, and both board assemblies are equipped with wireless power and data transfer capabilities.

[0089] Figure 3 The rotational LIDAR system 300 shown in [FIGURE REFERENCE] includes two main modules: the optical ranging device 320 and the rotational actuator 315 described in detail below. Additionally, the rotational LIDAR system 300 may interact with one or more examples of user interface hardware and software 305. Different examples of user interface hardware and software 305 may vary and may include, for example, a computer system having a monitor, keyboard, mouse, CPU, and memory; a touch screen in an automobile; a handheld device having a touch screen; or any other suitable user interface. The user interface hardware and software 305 may be local to the object on which the rotational LIDAR system 300 is installed, but may also be a remotely operated system. For example, commands and data to / from the rotational LIDAR system 300 may be routed through a cellular network (such as LTE), a personal area network (such as Bluetooth, Zigbee, etc.), a local area network (such as WiFi, IR, etc.), or a wide area network such as the Internet.

[0090] The user interface hardware and software 305 may present LIDAR data from the device to the user, but may also allow the user to control the rotational LIDAR system 300 with one or more commands. Example commands may include activating or deactivating the LIDAR system, specifying the photodetector exposure level, bias, sampling duration, and other operating parameters (such as the transmit pulse pattern and signal processing), commands specifying the optical emitter parameters such as brightness. Additionally, the commands may allow the user to select the method for displaying the results. The user interface may display the LIDAR system results, which may include, for example, a single-frame snapshot image, a constantly updated video image, and / or the display of other optical measurements of some or all pixels, such as the ambient noise intensity, the received signal intensity, the calibrated target reflectivity, the target classification (hard target, diffuse target, retroreflective target), range, signal-to-noise ratio, target radial velocity, the received signal time pulse width, signal polarization, noise polarization, etc. In some embodiments, the user interface hardware and software 305 may track the distance of an object from the vehicle (short range) and may potentially provide an alert to the driver or provide such tracking information for the analysis of the driver's behavior.

[0091] In some embodiments, the LIDAR system can communicate with the vehicle control unit 310 and can modify one or more parameters associated with the control of the vehicle based on the received LIDAR data. For example, in a fully autonomous vehicle, the LIDAR system can provide a real-time 3D image of the vehicle's surroundings to assist in navigation. In other cases, the LIDAR system can be used as part of an advanced driver assistance system (ADAS) or as part of a safety system, which can provide 3D image data to any number of different systems (e.g., adaptive cruise control, automatic parking, driver drowsiness monitoring, blind spot monitoring, collision avoidance systems, etc.). When the vehicle control unit 310 is communicatively coupled to the optical ranging device 320, an alert can be provided to the driver, or the proximity of an object can be tracked and / or displayed.

[0092] The optical ranging device 320 includes an optical sensing module 330, an optical transmission module 340, and an optical ranging system controller 350. The rotary actuator 315 includes at least two circuit board assemblies: a lower circuit board assembly 360 (also referred to herein as the base subsystem) and an upper circuit board assembly 380 (also referred to herein as the turret subsystem). The lower circuit board assembly 360 can be mechanically mounted to a fixed portion of a housing or casing (not shown), while the upper circuit board assembly 380 rotates freely about a rotational axis generally defined by a shaft ( Figure 3 not shown in the figure), which is also mounted to the housing (directly or indirectly). The optical ranging device 320 can be mechanically attached to the rotatable upper circuit board assembly 380 and thus rotates freely within the housing.

[0093] Although Figure 3 shows a particular arrangement of components within the optical ranging device 320 and the rotary actuator 315, in some embodiments, the particular components can be integrated into one or another module in a different manner than shown. As an example, the ranging system controller 350 (which can be, for example, an FPGA, an ASIC, or a more general computing device, such as an embedded system or a system on a chip (SOC)) can be directly mounted (e.g., soldered) to a printed circuit board that is part of the upper circuit board assembly 380. In other words, in some embodiments, parts of the rotary actuator can be integrated within the optical ranging device 320, and vice versa.

[0094] The rotary actuator 315 includes several different systems that are integrated onto one or more printed circuit boards of the lower and upper circuit board assemblies 360 and 380. For example, the rotary actuator 315 can include a brushless electric motor assembly, an optical communication subsystem, a wireless power transfer subsystem, and a base controller. These systems are formed by several pairs of cooperating circuit elements, each pair including one or more circuit elements on the lower circuit board assembly 360 cooperating (e.g., having complementary functions) with one or more circuit elements on the upper circuit board assembly 380. Complementary functions include, for example, the transmission (Tx) and reception (Rx) of power and / or data communication signals, as described in more detail below.

[0095] The brushless electric motor assembly includes a stator assembly 362 integrated onto the printed circuit board of the lower circuit board assembly 360, and a rotor assembly 382 integrated onto the printed circuit board of the upper circuit board assembly 380. The rotation of the rotor assembly 382 is driven in accordance with a drive signal (e.g., a three-phase drive current) from the motor driver circuit 364. In some embodiments, one or more motor control lines connect the motor driver circuit to the coils of the stator assembly 362 to allow the drive signal to be provided to the motor stator. Additionally, the motor driver circuit 364 can be electrically connected to the base controller 366 such that the base controller 366 can control the rotation rate of the rotor assembly and thus the rotation rate (i.e., the frame rate) of the optical ranging device 320.

[0096] In some embodiments, the rotor assembly 382 can rotate at a rate between 10 - 30 Hz. In some embodiments, the rotor assembly 382 can be a passive device that includes a series of permanent magnets attached to the circuit board of the upper circuit board assembly. These permanent magnets are attracted or repelled by the electromagnetic force (e.g., magnetic force) generated by the coils of the stator assembly to drive the rotation of the upper circuit board assembly 380 relative to the lower circuit board assembly 360. The rotational orientation of the upper circuit board assembly 380 can be tracked by a rotary encoder receiver 394, which can track the angular position of the upper circuit board assembly by detecting the passage of one or more features on the rotary encoder 374. A variety of different rotary encoder technologies can be employed. In some embodiments, the rotary encoder 374 is directly integrated onto the surface of the circuit board of the lower circuit board assembly 360.

[0097] The rotary actuator 310 may also include a wireless power system that includes a wireless power transmitter 372 and a wireless power receiver 392 configured in what is referred to herein as a rotary converter. The power transmitted from the transmitter 372 to the wireless power receiver 392 may be consumed by the optical ranging device 320 and / or any circuitry that requires power on the turntable / upper circuit board assembly. In some embodiments, all of the power required by the optical ranging device 320 is provided via the wireless power receiver 392, and thus no rotary electrical connectors such as slip rings or mercury-based devices are required, thereby increasing the overall system reliability and reducing the overall system cost.

[0098] The rotary actuator 310 may also include an optical communication subsystem that includes a plurality of optical transmitters (e.g., optical transmitters 378 and 396) and a plurality of optical receivers (e.g., optical receivers 376 and 398) for two-way non-contact data transfer between the rotary actuator 315 and the optical ranging device 320 (or to / from any other device or system mechanically coupled to the upper circuit board assembly 380 that is mechanically coupled to the rotary actuator 315). More specifically, the optical communication subsystem may include a set of base optical communication components that are attached (e.g., soldered) to the lower circuit board assembly 360 that is part of the fixed base of the LIDAR system 300; and may include a set of turntable optical communication components that are attached (e.g., soldered) to the rotating upper circuit board assembly 380 that is part of the rotating turntable of the LIDAR system 300. These optical communication components provide an uplink data channel for providing optical signals containing control signals to the optical ranging device 320, and also provide a downlink data channel for providing optical signals containing ranging and operating data from the optical ranging device 320 to the base controller 366, the user interface hardware and software 305, and / or the vehicle control unit 310.

[0099] The downlink optical communication channel from the upper circuit board assembly 360 to the lower circuit board assembly 380 can be formed between the optical downlink transmitter 396 and the optical downlink receiver 376. The optical ranging device 320 can be directly connected to the upper circuit board assembly 380 and can thus access the downlink optical communication channel to pass ranging and operation data down to the lower circuit board assembly 360 for further use. In some embodiments, the data passed down via the optical downlink in the optical signal can include range data (or possibly multiple ranges for a single pixel and angle, such as during fog / rain, when viewing through a glass window, etc.) for individual points (pixels) in the field, azimuth and vertex angle data, the returned signal-to-noise ratio (SNR) or signal strength, target reflectivity, the ambient near-infrared (NIR) level from each pixel's field of view, diagnostic operation information from the optical ranging device such as temperature, voltage level, etc. Additionally, data from any other systems connected to the upper circuit board 380 that is connected to the rotary actuator can be passed down via the optical downlink. For example, data from a high-speed RGB or thermal camera, line scan camera, etc.

[0100] The uplink optical communication channel from the lower circuit board assembly 360 can be formed between the optical uplink transmitter 378 and the optical uplink receiver 398. In some embodiments, control signals from the base controller 366 can be passed to the optical ranging device 320 via the uplink optical communication channel. For example, in some embodiments, the base controller 366 can monitor various temperatures in the device (as received from the downlink channel) and can send an emergency shutdown signal to the optical ranging device 320 via the uplink channel in the case of an overheat condition. In some embodiments, the base controller can be a mobile computer, such as a programmable system-on-chip employing an ARM+FPGA architecture with associated memory and I / O capabilities (e.g., Ethernet, etc.).

[0101] Ranging data can be generated by the optical ranging device 320 by transmitting one or more optical pulses from the optical transmission module 340 to an object in the field of view around the optical ranging device. The reflected portion of the transmitted light is then detected by the optical sensing module 330 after some delay time. Based on the delay time (commonly referred to as the "time of flight"), the distance to the reflecting surface can be determined. Other ranging methods can also be employed, such as continuous wave, Doppler, etc.

[0102] The optical transmission module 340 may include a transmitter array 342 and a transmit (Tx) optical system 344. The transmitter array 342 may be a one-dimensional or two-dimensional transmitter array that, when combined with the transmission optical system 344, forms an array of transmitter channels behind the volumetric imaging optics. These transmitter channels may optionally include micro-optical structures for beam shaping, beam steering, brightness enhancement, etc. The optical transmission module 340 may further include an optional processor 346 and a memory 348, but in some embodiments these computing resources may be incorporated into the rangefinder system controller 350. In some embodiments, pulse decoding techniques such as Barker code, etc. may be used. In these cases, the memory 348 may store a pulse code indicating when light should be transmitted. In one embodiment, the pulse code is stored as a sequence of integers stored in the memory.

[0103] The optical sensing module 330 may include a sensor array 332 and a receiver (Rx) optical system 334. The sensor array 332 may be a one-dimensional or two-dimensional photoelectric sensor array. In some embodiments, each photoelectric sensor may include a set of binary photon detectors (e.g., SPAD, etc.), while in other embodiments each photoelectric sensor may be a linear photodetector (e.g., APD). The receiver optical system 334 and the sensor array 332 together may form an array of micro-optical receiver channels behind the volumetric imaging optics as described in more detail below. Each micro-optical receiver channel measures light corresponding to image pixels in a different field of view of the surrounding volume. Due to the geometric configuration of the optical sensing module 330 and the optical transmission module 340, each photoelectric sensor (e.g., a set of SPADs) of the sensor array 332 may correspond to a specific transmitter of the transmitter array 342. In an alternative embodiment, each sensor of the sensor array 332 may correspond to multiple transmitters (e.g., a cluster of VCSELs) of the transmitter array 342. In yet another embodiment, a single large transmitter (e.g., a laser diode bar) may be in the transmitter array 342 and may correspond to multiple sensors within the sensor array 336.

[0104] In some embodiments, the sensor array 332 of the light sensing module 330 can be fabricated using, for example, CMOS technology as part of an integrated device on a single substrate, which includes a photoelectric sensor array, a processor 336 for signal processing of the raw signals from individual photoelectric sensors (or groups of photoelectric sensors) in the array, and a memory 338. The integrated structure including the sensor array 332, the processor 336, and the memory 338 can be fabricated as a dedicated ASIC. In some embodiments, the micro-optical component that is part of the receiver optical system 334 can also be part of the integrated structure in which the sensor array 332, the processor 334, and the memory 338 are components. In such instances, the micro-optical component can be formed on the ASIC such that it becomes part of the integrated structure with separate substrate layers for each layer of the receiver channel. For example, a pore layer, a collimating lens layer, an optical filter layer, and a photodetector layer can be stacked and bonded at the wafer level to multiple ASICs before dicing. The pore layer can be formed by disposing an opaque substrate over a transparent substrate or by coating the transparent substrate with an opaque film. In such embodiments, the dicing step forms multiple ASICs, each ASIC having its own micro-optical structure directly bonded thereto. As another example, the micro-optical component can be formed as a separate integrated structure that can be directly bonded to the ASIC after the ASIC is separated from the larger wafer via a dicing process. In this way, the ASIC and the micro-optical structure can be bonded together to form a single integrated structure. In still other embodiments, one or more components of the Rx module 330 can be external to the integrated structure. For example, the pore layer can be implemented as a separate metal sheet with pinholes.

[0105] As mentioned above, the processor 336 and the memory 338 (e.g., SRAM) can perform signal processing. As an example of signal processing, for each photoelectric sensor or group of photoelectric sensors, the memory 338 of the light sensing module 330 can accumulate the count of photons detected within successive time partitions, and these time partitions combined can be used to recreate the time series of the reflected light pulses (i.e., photon count versus time). This time series of the aggregated photon counts is referred to herein as the intensity histogram (or simply histogram). Additionally, the processor 336 can implement specific signal processing techniques such as matched filtering to help recover the photon time series that is less sensitive to pulse shape distortion that may occur due to SPAD saturation and quenching. In some embodiments, one or more components of the ranging system controller 350 can also be integrated into the same ASIC as the sensor array 332, the processor 336, and the memory 338, thereby eliminating the need for a separate ranging controller module.

[0106] In some embodiments, the output from processor 336 is sent to ranging system controller 350 for further processing. For example, the data can be encoded by one or more encoders of ranging system controller 350 and then sent as a data packet via an optical downlink to lower circuit board assembly 360. Ranging system controller 350 can be implemented in a variety of ways, including, for example, by using a programmable logic device such as an FPGA, as an ASIC or part of an ASIC, using a processor 352 with a memory 354, and some combination of the above. Ranging system controller 350 can cooperate with base controller 366 or operate independently of base controller (via pre-programmed instructions) to control light sensing module 330 by sending commands that include starting and stopping light detection and adjusting photodetector parameters. Similarly, ranging system controller 350 can control light transmission module 340 by sending commands or relaying commands from base controller 366 that include starting and stopping light emission control and control of other light emitter parameters that can be adjusted, such as emitter temperature control (for wavelength tuning), emitter drive power, and / or voltage.

[0107] If emitter array 342 has multiple independent drive circuits, there can be multiple on / off signals that can be properly sequenced by ranging system controller 350. Similarly, if the emitter array includes multiple temperature control circuits to tune different emitters in the array in different ways, the transmitter parameters can include multiple temperature control signals. In some embodiments, ranging system controller 350 has one or more wired interfaces or connectors (e.g., traces on a circuit board) for exchanging data with light sensing module 330 and with light transmission module 340. In other embodiments, ranging system controller 320 communicates with light sensing module 330 and light transmission module 340 over a wireless interconnect such as an optical communication link.

[0108] III. Light Transmission and Detection

[0109] Figure 4A and 4B Depicts an illustrative example of a light transmission and detection process for an optical ranging system according to some embodiments, focusing on the emitter array and sensor array that form the arrangement of emitter-sensor channels, as introduced above with reference to FIG. 2. Figure 4A Depicts an optical ranging system 400 (e.g., solid state or and / or scanning) that collects three-dimensional distance data of a volume or scene 450 external to the optical ranging system 400. Figure 4B Is an enlarged view of the optical ranging system 400 from Figure 4A The optical ranging system 400 can represent any of the optical ranging systems 200, 220, or 300 discussed above, as well as various optical ranging devices discussed below. Figure 4A and4B is a highly simplified diagram highlighting the relationship between the emitter and the sensor, and therefore other components are not shown.

[0110] like Figure 4A and 4B As shown in FIG. 4 , optical ranging system 400 includes an array of light emitters 410 and an array of light sensors 420. Light emitter array 410 includes an array of light emitters (e.g., an array of VCELs, etc.) including individual emitters such as emitter 410(1) and emitter 410(9). Light sensor array 420 includes an array of photosensors including individual photosensors such as sensors 420(1) and 420(9). The photosensors may be pixelated photosensors that employ a set of discrete photodetectors, such as single photon avalanche diodes (SPADs), for each pixel. However, various embodiments may deploy other types of photosensors. In some embodiments, optical ranging system 400 includes one or more sets of bulk optical elements (not shown), referred to herein as bulk optics, placed in front of light emitter array 410 and / or light sensor array 420 for redirecting beams in the directions shown.

[0111] Each emitter may be slightly offset from its neighbors and may be configured to transmit light pulses into a different field of view than its neighboring emitters, thereby illuminating only the respective field of view associated with that emitter. For example, emitter 410(1) emits illumination beam 415(1) (formed by one or more light pulses) into circular field of view 452 (whose size is exaggerated for clarity). Similarly, emitter 410(9) emits illumination beam 415(9) (also referred to as an emitter channel) into circular field of view 454. Although Figure 4A and 4B Although not shown to avoid complexity, each emitter emits a respective illumination beam into its corresponding field of view, thereby illuminating a 2D array of fields of view (in this example, twenty-one distinct fields of view correspond to the twenty-one emitters of light emitter array 410 arranged in a 3 x 7 array).

[0112] Each field of view illuminated by an emitter can be considered as a pixel or spot in the corresponding 3D image generated from the ranging data. Each emitter channel can be distinct for each emitter and non-overlapping with other emitter channels, i.e., there is a one-to-one mapping between the set of emitters and the set of non-overlapping fields of view. Figure 4A and 4B In the example of , the system can sample twenty-one distinct points in 3D space. Denser point sampling can be achieved by having a denser array of emitters or by scanning the angular position of the emitter beams over time so that one emitter can sample several points in space.

[0113] Each sensor can be slightly offset from its neighbors, and similar to the transmitters described above, each sensor can see a different field of view of the scene in front of the sensor. In addition, the field of view of each sensor is generally consistent with the field of view of the corresponding transmitter channel, e.g., overlapping with it and having the same size. Similar to the transmitters described above, the field of view of the sensors can be scanned by rotation of the assembly. Galvanometers, MEMS mirrors, or scanning can also be achieved via some other method.

[0114] In Figure 4A and 4B the distance between the corresponding transmitter-sensor channels is exaggerated relative to the distance to an object in the field of view. In practice, the distance to an object in the field of view is much larger than the distance between the corresponding transmitter-sensor channels, and thus the path of light from the transmitter to the object is approximately parallel to the path of the reflected light from the object back to the sensor (i.e., it is almost "reflected back"). Accordingly, there is a certain distance range in front of the system 400 within which the fields of view of the individual sensors and transmitters overlap, and it is within this distance range that the system can most accurately determine depth information.

[0115] Because the field of view of the transmitter overlaps with the field of view of its corresponding sensor, each sensor channel can ideally detect the reflected illumination beam originating from its corresponding transmitter channel, ideally without crosstalk, i.e., no reflected light from other illumination beams is detected. For example, transmitter 410(1) emits illumination beam 415(1) into circular field of view 452, and some of the illumination beams are reflected from object 460 as reflected beam 425(1). Ideally, reflected beam 425(1) is detected only by sensor 420(1). Thus, transmitter 410(1) and sensor 420(1) share the same field of view (i.e., field of view 452) and form a transmitter-sensor pair. Similarly, transmitter 410(9) and sensor 420(9) form a transmitter-sensor pair, sharing field of view 454. In some embodiments, the transmitter array 410 and sensor array 420 are designed and configured (in combination with volumetric optics) such that the field of view of each transmitter-sensor pair does not overlap with the field of view of other transmitter-sensor pairs (beyond a threshold distance).

[0116] Although the transmitter-sensor pairs are shown in Figure 4A and 4B as being in the same relative positions in their respective arrays, any transmitter can be paired with any sensor, depending on the design of the optics used in the system. In some embodiments, it may be advantageous from a design simplicity / cost perspective to have the same volumetric imaging optics in front of the transmitter / sensor pairs in the same arrangement.

[0117] During a ranging measurement, reflected light from different fields of view around a volume distributed around the LIDAR system is collected and processed by various sensors to obtain range information of any objects in each corresponding field of view. As described above, time-of-flight techniques can be used, where a light emitter emits precisely timed pulses, and the reflections of the pulses are detected by the corresponding sensors after some time. The time elapsed between the emission and the detection, along with the known speed of light, is then used to calculate the distance to the reflecting surface. In some embodiments, additional information can be obtained by the sensors to determine other properties of the reflecting surface besides the distance. For example, the Doppler shift of the pulse can be measured by the sensors and used to calculate the relative velocity between the sensor and the reflecting surface.

[0118] In some embodiments, the LIDAR system can consist of a relatively large 2D array of emitters and sensor channels and operate as a solid-state LIDAR, i.e., it can obtain frames of range data without scanning the orientation of the emitters and / or sensors. In other embodiments, the emitters and sensors can be scanned (e.g., rotated about an axis) to ensure that the fields of view of the set of emitters and sensors sample a complete 360-degree region (or some useful fraction of the 360-degree region) of the surrounding volume. For example, range data collected from the scanning system over a certain predefined time period can then be post-processed into one or more data frames, which can then be further processed into one or more depth images or 3D point clouds. The depth images and / or 3D point clouds can be further processed into map tiles for 3D mapping and navigation applications.

[0119] IV. LIDAR Unit with Integrated Architecture

[0120] Figures 5A - 5B A rotating LIDAR system 500 employing a 360 scanning architecture according to some embodiments of the present disclosure is shown. In some embodiments, the LIDAR system 500 can spin in a clockwise or counterclockwise direction to observe the surrounding field around the vehicle. The system 500 can include a fixed base housing 502, an optically transparent window 504, and a fixed cover 506 for providing protection to the internal components of the LIDAR system 500. The window 504 can be made of a transparent material to allow bidirectional transmission of near-IR light. The fixed base housing 502, the window 504, and the cover 506 form a water-resistant or waterproof system housing or enclosure 508 that completely encloses the internal components of the LIDAR system 500 to protect the components from various factors. The housing / enclosure 508 can represent, for example, the housing 220 discussed above with respect to Figure 2A In some embodiments, the enclosure can have a generally cylindrical shape, as Figure 5A shown.

[0121] In some embodiments, the window 504 can extend entirely around the perimeter of the housing 508 and be attached to the base housing 502 and the lid 506 in a fixed relationship. In such embodiments, the optical ranging device 510 (shown in Figure 5B ) can rotate behind the window 504 within the housing 508. In other embodiments, the window 504 can rotate with the optical ranging device 510. The configuration of the base housing 502, the window 504, and the fixed lid 506 shown in Figure 5A is merely one example of a housing 508 according to embodiments of the present disclosure. Those skilled in the art will recognize that other configurations of suitable housings for the LIDAR system 500 are possible. As one example of a different configuration, the lid 506 can be part of the window 504. As another example, in embodiments where the window 504 rotates with the optical ranging device 510, the window 504 can include two or more separate windows separated by opaque regions. For example, in some embodiments, the LIDAR system 500 can include a first window aligned with an optical transmitter and a second window spaced apart from the first window and aligned with an optical receiver. As used herein, "aligned" means that the optical transmitter or receiver transmits or receives light through the window.

[0122] The internal components of the system 500 (not shown in Figure 5A ) can include a rotary actuator and an optical ranging device, such as the actuator 310 and the optical ranging device 320 described with respect to Figure 3 . The optical ranging device can be aligned with the window 504 and can be spun by the rotary actuator to project a beam of light pulses through the window 504 into the field around the LIDAR system 500 as the optical ranging device continuously spins 360 degrees in a clockwise or counterclockwise direction. The light reflected back from the field through the window 504 can then be detected by the optical ranging device to determine the distance to an object in the field, as described herein.

[0123] As described in more detail below, the rotating LIDAR system 500 can employ a highly integrated architecture and achieve a highly compact configuration for the internal mechanical elements and circuitry. Accordingly, the overall form factor of a LIDAR system according to some embodiments of the present disclosure can be smaller than many existing systems, such as its overall volume is similar to or smaller than Figure 5A the overall volume of the coffee cup 550 visible in

[0124] Figure 5B FIG. shows an embodiment of a LIDAR system 500 according to some embodiments of the present disclosure, where the outer housing / system housing 508 (including the window 504 and the lid 506) has been removed to highlight the integrated stacked board design. As Figure 5BAs shown, the rotational LIDAR system 500 includes a light ranging device 510, which includes an optical transmitter 512 and an optical receiver 514 mounted within a housing 515. The housing includes a first housing portion 516 for the optical transmitter and a second housing portion 518 for the optical receiver. The light ranging device 510 is mechanically and fixedly connected to a printed circuit board 522 forming the rotating end of a stacked plate rotary actuator 520. The fixed side of the stacked plate rotary actuator 520 including the printed circuit board 524 is attached to the base portion 502 of the housing.

[0125] As described in more detail below, embodiments of the LIDAR system have a highly integrated design, making it particularly suitable for highly compact rotational LIDAR systems. Various functional elements (mechanical and electronic) of the LIDAR system are integrated into a stacked circuit board assembly that includes the one or more circuit boards stacked in a parallel arrangement, such as Figure 5B shown, for example, circuit boards 522, 524, 526, and 528. In some embodiments, the power system, electric motor, communication system, and LIDAR control system are all integrated into one or more stacked planar circuit boards of the stacked plate rotary actuator 520. The light ranging device 510 can be conveniently attached to the top plate 522 by means of one or more multi-pin connectors, etc. (not shown). As will be detailed below, the boards may include central pores through which a central shaft passes. The upper board may be attached to the upper portion of the shaft via one or more bearings. Each of the boards may be arranged such that its planar surface is perpendicular to the shaft and thus perpendicular to the axis of rotation. Due to this configuration, assembly and maintenance are much simpler compared to other systems where the orientation of multiple boards within the LIDAR system varies.

[0126] Figures 6A - 6C Cross-sectional views of LIDAR systems 600, 650, and 660 according to various embodiments of the present disclosure are shown. More specifically, Figures 6A - 6C the individual components shown in Figure 3 generally correspond to the components already described above with reference to Figures 6A - 6C where the views shown in Figure 6A and 6B each show an embodiment employing optical communication between an upper and a lower circuit board assembly, and Figure 6C shows an embodiment employing inductive communication between an upper and a lower circuit board assembly. Figures 6D - 6E A view of the surface of an individual circuit board according to some embodiments is provided to further illustrate the concentric circumferential arrangement of several individual circuit elements.

[0127] Now referring to Figure 6A, the LIDAR system 600, which can represent the LIDAR system 500, can include a light ranging device 602 together with upper and lower circuit board assemblies 610 and 620 (respectively), where the upper board assembly 610 rotates relative to the lower board assembly 620 about an axis 605 perpendicular to the board assemblies. The circuit board assemblies 610 and 620 are each structural components of the LIDAR system 600 that hold all or substantially all components of the LIDAR system. This two-piece design enables the system 600 to have a reduced size and increased reliability compared to many currently available LIDAR systems, and enables the system 600 to be manufactured at a reduced cost.

[0128] The light ranging device 602 can be mounted to one of the circuit boards in the upper board assembly 610 so that the light ranging device can rotate with the upper board assembly 610, while the lower board assembly 620 can be mounted to the base 604 and / or side wall 606, each of which is part of a fixed base of the LIDAR system 600. The rotation of the upper circuit board assembly 610 and the light ranging device 602 is achieved by a bearing system 607 on a hollow shaft 606 centered along the longitudinal axis or axis of rotation 605.

[0129] Each of the assemblies 610, 620 can include two or more stacked planar circuit boards arranged in a parallel relationship to each other. In the particular embodiment shown, the upper assembly 610 includes a rotor communication board 612 and a rotor control board 614, while the lower assembly 620 includes a stator communication board 622 and a stator control board 624. An electric motor can be directly integrated on the board assemblies together with an encoder, a wireless power system, and an optical communication system as described in more detail below. Many or all of these same elements are also respectively integrated on the board assemblies of the LIDAR systems 650 and 660 shown in Figure 6B and 6C For the sake of simplicity in the description of Figures 6A - 6C and to avoid repetition, the same reference numerals are used to indicate the same elements, and the description of such same elements is generally not repeated.

[0130] The highly integrated stacked board design of the LIDAR system 600 provides a system that has a much simplified assembly process compared to a system that uses many independent modules for each of the different functional elements of the LIDAR system. In an alternative embodiment, the LIDAR systems of the present disclosure can include upper and lower board assemblies, each of which is a single circuit board, thus further simplifying the stacked board design. For example, Figure 6B the LIDAR system 650 shown in

[0131] Although Figures 6A - 6CAlthough not explicitly shown in the figure, one or more support power circuits, drive / control circuits, and communication circuits may be paired with each of the systems discussed below, and these support systems may also be integrated onto one or more circuit boards of the rotary actuator. For example, a motor driver for supplying three-phase drive current to the solenoid of the stator may be attached to the surface of the circuit board of the lower circuit board assembly 620. The power drive and regulation circuits may be paired with the wireless power transfer assembly and mounted on the upper and / or lower board assemblies. Support circuits for digital communication systems such as buffers, LED / laser current drivers, encoders / decoders, clock recovery circuits, and photodetector drive and regulation circuits may also be mounted on one or more boards of the circuit board assembly. Some of these components will be discussed in further detail below, but those of ordinary skill in the art will understand that any number of arrangements and configurations of standard circuit components may be employed without departing from the scope of the present disclosure. In some embodiments, due to the nature of the rotationally symmetric optical uplink, wireless power rotary converter, brushless DC motor, and rotary encoder, any concentric ordering of these subsystems around the shaft may be employed.

[0132] V. Optical Link

[0133] 1. Integrated Central Optical Downlink

[0134] In some embodiments, the hollow shaft 606 may serve not only as the central structural member of each of the support board assemblies but also as a downlink optical communication channel (“downlink channel”) for providing data such as ranging and / or operational data from the turntable assembly to the control and processing circuits located in the lower circuit board assembly 620 (also referred to as the base system). The optical downlink channel may include an optical downlink transmitter 626 and an optical downlink receiver 628, each of which may be centered along the rotational axis 605. The optical downlink transmitter 626 may be directly attached (e.g., welded) to the surface of the circuit board of the upper circuit board assembly 610 and may be positioned such that it can transmit optical signals through the central hole or opening in the hollow shaft 606. Similarly, the optical downlink receiver 628 may be directly attached (e.g., welded) to the surface of the circuit board of the lower circuit board assembly 620. The optical downlink receiver 628 may be positioned at the lower end of the shaft and aligned with the optical downlink transmitter 626 such that it can receive the optical signals transmitted from the optical downlink transmitter 626.

[0135] The optical transmitters and receivers for the optical downlink of the rotary actuator may be any suitable optical emitter or detector. For example, IR LEDs, laser diodes, VCSELs, etc. may be used for the optical emitter. Similarly, any suitable light detection technology may be used for the receiver, such as photodiodes, etc.

[0136] 2. Integrated optical uplink

[0137] The optical uplink channels can be formed between a circumferential arrangement of a plurality of optical uplink transmitters 642 and a complementary circumferential arrangement of a plurality of optical uplink receivers 632. Similar to the optical downlink transmitter / receiver pairs, individual optical uplink transmitters and optical uplink receivers can be directly attached (e.g., welded) to the respective circuit boards of the lower and upper circuit board assemblies. The optical communication components disposed on the lower circuit board assembly are also referred to herein as "substrate optical communication components". The optical communication components disposed on the upper circuit board assembly or turntable are also referred to herein as "turntable optical communication components". Advantageously, the wall of the hollow shaft 606 provides optical isolation between the uplink and downlink channels and thus minimizes crosstalk.

[0138] The circumferentially arranged individual transmitters and receivers can be coupled together to be used together as a single composite receiver and a single composite transmitter. For example, as the system rotates, the overall optical intensity of the uplink signal detected along the complete arrangement of the optical uplink receivers varies only slightly as the individual transmitters / detectors pass each other. Additionally, the number of individual transmitters in the composite transmitter can be the same as or different from the number of individual receivers in the composite receiver.

[0139] The optical transmitters and receivers for the optical uplink of the rotary actuator can be any suitable type of optical transmitter or detector. For example, a ring of IR LEDs, laser diodes, VCSELs, etc. can be used as the composite optical transmitter. Similarly, any suitable type of optical detection technology can be used for the receiver, e.g., a ring of photodiodes, etc. can be used as the composite optical receiver. Additionally, the optical transmitters and receivers for the optical uplink can be of the same or different types (e.g., power and wavelength) as the optical transmitters and receivers for the downlink.

[0140] An example of the circumferential arrangement of the optical uplink transmitters 642 is shown in Figure 6D which shows a top view of a fixed circuit board (e.g., Figure 6D circuit board 622 of Figure 6A . In this example, there are six (6) optical uplink transmitters 642 circumferentially arranged around a central hole 672. The six (6) transmitters are evenly spaced around a circle 674, the center of which is located at the center of the shaft (and thus the center of the hole 672) and thus coincides with the axis of rotation.

[0141] The opposite surfaces of the rotating circuit boards (e.g., Figure 6A circuit board 612 of Figure 6B orFigure 6E as shown Figure 6E shows a bottom view of a rotating circuit board according to some embodiments. In this example, there are seven (7) optical uplink receivers circumferentially arranged around a central hole 672. The seven (7) receivers are evenly spaced around a circle 684, the center of which is located at the center of the shaft and thus coincides with the axis of rotation. Accordingly, as the board rotates, the arrangement of the optical uplink receivers 632 rotates around the axis of rotation. Since the radius of circle 684 is the same as the radius of circle 674, the transmitters are aligned with the receivers and rotation only results in a slight increase and decrease of the average signal over time, where the frequency is a multiple of the rotation frequency of the turntable system. The number of transmitters required for a reliable uplink channel depends on both the nominal power of the transmitters and the divergence of the light cone emitted from each transmitter. Ideally, the spot size of the transmitter light at the front surface of the rotating plate is large enough such that the individual spots overlap to the extent that the overall variation in the average intensity seen by the set of receivers is below a specified value as the rotating plate rotates.

[0142] Although Figure 6D and 6E depict embodiments in which the optical downlink channel is formed within the hollow shaft 606 and the optical uplink channel is formed between a circumferential arrangement of a plurality of optical uplink transmitters and a complementary circumferential arrangement of a plurality of optical uplink receivers disposed outside the shaft, other arrangements of the optical channels are possible in other embodiments. For example, in some embodiments, the uplink channel may be formed within the hollow shaft 606 and the downlink channel may be formed outside the shaft. In still other arrangements, both the downlink and uplink channels may be formed inside the shaft 606 (e.g., using separate optical waveguides), or both the downlink channel and the uplink channel may be formed outside the shaft in separate circumferential arrangements of optical components.

[0143] VI. Inductive Communication Link

[0144] Referring back to Figure 6C , Figure 6CAn embodiment showing inductive communication systems 666, 668 between upper and lower circuit board assemblies is presented. In this example, the data uplink and downlink are provided by pairs of coils 666a-e and 668a-e mounted on the lower and upper circuit board assemblies respectively, as shown. The coils can include both data lines and clock lines. Each coil can be embedded within a separate channel (e.g., an annular channel) of a housing, such as upper coil housing 666 and lower coil housing 668 that are themselves mounted to the surface of their respective circuit boards. In some embodiments, there can be several coils for multiple inductive data lines, e.g., downlink channel 1 transmitter coil 666b and downlink channel 1 receiver coil 668b, downlink channel 2 transmitter coil 666c and downlink channel 2 receiver coil 668c. In some embodiments, the downlink clock signal can be transmitted via separate coil pairs such as downlink clock transmitter coil 666a and downlink clock receiver coil 668a. Similarly, the data uplink channel can be formed by one or more pairs of coils, e.g., by uplink transmitter coil 668d and uplink receiver 666d. Similar to the downlink, the data uplink clock signal can also have a dedicated channel formed by a pair of coils, such as uplink clock transmitter coil 668e and uplink clock receiver coil 666e.

[0145] In some embodiments, the use of inductive communication links can provide several advantages relative to optical configurations, including: (1) replacing the hollow shaft 606 with a simpler and easier-to-construct solid shaft 665; (2) in some cases, the inductive coil arrangement may require less stringent tolerances for mechanical alignment and thus have a lower manufacturing cost; (3) an easier arrangement for transferring multiple information channels between boards; (4) it is possible to transfer the clock along with the data, which eliminates the need for clock and data recovery (CDR) chips; (5) it can allow scaling of the bandwidth by providing a multi-channel (parallel) data transmission line arrangement; and (6) by distributing separate clock signals between the boards, deterministic timing behavior between the lower board assembly (stator) and the upper board assembly / optical ranging unit (rotor) can be achieved.

[0146] Although Figure 6CAn embodiment with five coil pairs is shown, but any number of coil pairs can be implemented without departing from the scope of the present disclosure. For example, a two-coil pair configuration with only one data uplink channel and one downlink channel can be implemented. In this case, a clock signal can be provided via the uplink channel, and the downlink clock can be derived from this uplink clock signal. In other embodiments, three coil pairs can be employed, one for uplink data, one for downlink data, and one for the uplink clock signal, again with the downlink clock signal being derived from the uplink clock signal. A four-coil pair configuration providing both uplink and downlink clock signal channels is also possible. In addition to all of the above, any number of data channels can be employed without departing from the scope of the present disclosure.

[0147] VII. Integrated Electric Motor

[0148] According to certain embodiments, an electric rotary motor can be directly integrated onto a circuit board. The motor can have a "flat" or "axial" design, where a planar rotor assembly on a rotor plate faces a stator assembly on a relative stator plate. The stator and rotor assemblies of the electric motor can be integrated onto the plate of a rotary actuator 608, i.e., the elements of the electric motor are among the many components on the surface of a printed circuit board, and thus the LIDAR system 600 does not require a separate motor module. For example, referring back to Figure 6D , the stator assembly 644 can include, for example, an annular arrangement of a plurality of stator elements 644(i) such as vertically oriented solenoids (whose longitudinal axes are perpendicular to the surface of the plate), with the stator elements attached (e.g., using an adhesive) to the plate of a lower circuit board assembly 620 (e.g., plate 622) or attached to a soft magnetic core, which is then attached to the lower circuit board assembly 620. Examples of stator elements are shown in Figure 6D in a top view. Each stator element 644(i) can include a solenoid coil 644a wound around a core 644b of a magnetic material such as ferrite. The coils are oriented such that the magnetic field exiting the solenoid is generally oriented in a direction substantially perpendicular to the plane of the circuit board. In the embodiment shown in Figure 6D , the stator assembly 644 includes eighteen (18) individual stator elements 644(i) evenly spaced from each other, but embodiments of the present disclosure are not limited to stator assemblies having any particular number of stator elements, and other embodiments can include fewer or more individual stator elements 644(i). For example, in some embodiments, the stator assembly 644 includes at least 12 individual stator elements 644(i) in an annular arrangement. And, in some embodiments, the number of individual stator elements 644(i) in the stator assembly 644 is a multiple of three, and the motor driver circuit and controller ( Figure 6D(not shown) provides a three-phase alternating signal to the stator assembly 644 to control the rotational speed of the control board 622 and thus the rotational speed of the optical ranging device 602.

[0149] Positioned directly opposite the motor stator assembly 644 and attached to the board of the upper circuit board assembly 610 is the motor rotor assembly 634. In some embodiments, the motor rotor assembly 634 can be a passive component that includes an annular arrangement of permanent magnets 634(i), where the magnetic poles are arranged in an alternating pattern to sequentially repel and attract the openings of the various solenoid coils of the stator assembly, as Figure 6E more particularly shown in the board view as shown. Thus, as Figure 6E shown, the magnetic poles of each individual magnet 634a can be arranged opposite its neighboring magnet 634b, and the magnetic poles of each individual magnet 634b can be arranged opposite its neighboring magnet 634a. Additionally, although Figure 6E the embodiment of the stator assembly 644 shown includes twenty-four (24) individual magnets 634(i) that are evenly spaced from each other, embodiments of the present disclosure are not limited to a rotor assembly having any particular number of elements, and other embodiments can include fewer or more individual magnets 634(i). Additionally, as Figure 6D and 6E can be seen, the motor stator assembly 644 and the motor rotor assembly 634 can have an overall toroidal shape, where both the stator and rotor circles have the same radius and center position (e.g., the two rings can be centered on the shaft).

[0150] Although Figure 6D and 6E the embodiments shown use rotor elements that are permanent magnets and stator elements that are solenoid coils, the opposite configuration can also be used without departing from the scope of the present disclosure. For example, the solenoid can be used as the rotor element and the permanent magnet can be used as the stator element, in which case the power to the stator element can be provided by the wireless power transfer system described below. Additionally, instead of using permanent magnets as the rotor / stator elements, electromagnets can be used in some embodiments. Those of ordinary skill in the art who benefit from the present disclosure will understand that any implementation of a PCB-mounted brushless DC motor can be used, for example, any non-contact configuration of solenoid coils and permanent magnet elements can be used, and any drive scheme that implements the rotational motion of the basic hardware can be used without departing from the scope of the present disclosure.

[0151] VIII. Integrated Wireless Power Transfer System

[0152] To provide power to the circuit elements connected to the rotating upper circuit board assembly 610, the rotary actuator 608 includes a wireless power system, also referred to herein as a rotary converter. The wireless power system includes a wireless power transmission subsystem that includes a wireless power transmitter 648, and a wireless power reception subsystem that includes a wireless power receiver 638. The wireless power transmitter 648 can be a transmitter coil in the form of a circular loop antenna (e.g., a single-turn or multi-turn coil) that is attached to the surface of a circuit board (e.g., board 622) of the lower circuit board assembly 620 as shown, for example, in Figure 6D Similarly, the wireless power receiver 638 can be a receiver coil in the form of a circular loop antenna (e.g., a single-turn or multi-turn coil) that is attached to the surface of a circuit board (e.g., board 612) of the upper circuit board assembly 610 as shown in Figure 6E . The centers of both the wireless power transmitter 648 and the wireless power receiver 638 are located at the center of the hollow shaft 606 and are thus concentric with the optical encoder ring, the electric motor assembly, and the optical uplink receiver / transmitter. Advantageously, the wireless power transmitter and receiver can be located in the outermost regions of boards 622 and 612 to maximize the area (and thus the inductance) of the circular loop, which maximizes the power transfer efficiency and advantageously prevents light from the environment or the interior of the LIDAR system from reaching the optical encoder, uplink, or downlink.

[0153] In some embodiments, the wireless power transmitter 648 and the wireless power receiver 638 can be placed in an annular region of their respective boards, the walls and bottom of which are formed of a magnetic material such as ferrite. For example, Figure 6E shows a wireless power receiver 638 disposed in an annular region formed by ferrite walls 686 and 688 ( Figures 6A - 6C , not shown in the figure) and an obscured ferrite bottom. This arrangement of ferrite material is depicted in Figure 6F , Figure 6F which is a simplified cross-sectional view of a portion of a multi-coil wireless power receiver 638 positioned within an annular channel defined by ferrite walls 686, 688, and bottom ferrite wall 690. Figure 6F The arrangement shown in

[0154] IX. Integrated Optical Encoder

[0155] The rotary actuator 608 further includes an integrated optical encoder assembly that allows reading of the angular position of the upper circuit board assembly 610 relative to the lower circuit board assembly 620. The optical encoder assembly includes a patterned annular optical encoder 646 and a rotary encoder detector 636 for reading the angular position of the assembly by, for example, detecting the number of patterns of the annular optical encoder 646 that pass by the rotary encoder detector 636 as the system rotates and counting that number. In some embodiments, the rotary encoder detector 636 may include an illumination device, such as an LED, and a detector, such as a photodiode or imaging detector, for illuminating and detecting the patterned surface of the annular optical encoder. In some embodiments, the annular optical encoder may include a start code that occurs at a unique position on the annulus or provides an absolute coding pattern, thereby enabling absolute angular orientation measurement. In some embodiments, the encoder system is magnetic rather than optical and relies on similarly positioned magnetic encoder strips and magnetic encoder readers.

[0156] In some embodiments, the annular optical encoder 646 may be attached to the surface of a circuit board (e.g., board 622) of the lower circuit board assembly 620, and the rotary encoder detector 636 may be attached to the surface of the upper circuit board assembly 610 (e.g., board 612), as shown here, or vice versa. Regardless of which board it is placed on, the annular optical encoder 646 may be arranged such that its center is at the center of the hollow shaft 606 and is thus concentric with both the electric motor assembly and the optical uplink receiver / transmitter as shown, for example Figure 6D in. In some embodiments, the rotary encoder detector 636 is located on a rotating circuit board anywhere above the annular optical encoder 646, such as as Figure 6E shown.

[0157] Advantageously, the encoder assembly may be positioned between the wireless power transfer system and the electric motor assembly to maximize optical isolation between the encoder detector and the transmitter of the optical uplink system. As shown in the example of Figure 6A , in some embodiments, the annular optical encoder 646 may be on the stator side of the rotary actuator 606, while the rotary encoder detector 636 is on the rotor side. Although this is a non-standard configuration for a rotary actuator, this configuration is advantageous for LIDAR applications. For example, by removing the rotary connection between the rotary encoder detector 636 and the optical ranging device 602 in this way, an implementation of a low latency connection between the two systems may be implemented. In LIDAR applications, a low latency connection may be important for quickly obtaining angular position measurements of the rotary encoder detector 636 and correlating the current ranging information with the current angular position of the rotor to increase spatial accuracy.

[0158] X. Assembly Method

[0159] Figure 7 -8 shows an exploded view of a LIDAR system according to some embodiments to illustrate the assembly process. Figure 7 Shows the mechanical assembly of the lower circuit board assembly (also referred to herein as the base assembly). FIG. 8 shows the mechanical assembly of the upper circuit board assembly and its attachment to both the lower circuit board assembly and the optical ranging device, thereby forming a complete LIDAR system.

[0160] 1. Assemble the lower circuit board assembly

[0161] Figure 7 An exploded view of the lower circuit board assembly 700 according to some embodiments is shown to illustrate the assembly process of a compact LIDAR system. In the Figure 7 embodiment shown, the lower circuit board assembly 700 has a two-board configuration similar to that described above with reference to Figure 6A . Specifically, the lower circuit board assembly 700 includes first and second sub-boards, referred to herein as the base control board 720 and the stator board 730. In some embodiments, the base control board 720 and the stator board 730 correspond to board 643 and board 641, respectively, as Figure 6A shown.

[0162] The assembly of the lower circuit board assembly 700 can begin with the base control board 720 being mechanically attached to the base housing unit 710 by means of screws 728. As has been referenced above with Figure 3 and 6A described, the base control board may include a number of circuit elements, including a base controller, similar to base controller 366. Support circuits (such as drivers) for elements of the optical communication system, wireless power transfer system, and rotary encoder system may also be included on the base control board. To implement the optical downlink communication channel, the optical downlink receiver 722 may be mounted (e.g., soldered) to the upper surface of the base control board 720, in the central region of the board, as described above with reference to Figure 6A .

[0163] In some embodiments (e.g., as described above with reference to Figure 6B ), the optical downlink receiver 722 and other support circuit elements are directly integrated onto the stator board 730, thereby eliminating the need for a separate base control board 720. In this case, the assembly of the lower circuit board assembly 700 can begin by directly attaching the thermal dissipation element 725 to the base 710, or in the absence of a base or thermal dissipation element 725, the assembly can begin by mounting the stator board 730.

[0164] After the base control board 720 is attached to the base 710, the shaft 715 can be attached to the base control board 720 using screws 706. In some embodiments, the shaft 715 can be directly attached to the base 710 via a bearing system (shown in more detail below in Figure 8A and 8B to improve the heat conduction from the upper circuit board assembly to the base 710. As described above with reference to Figures 6A - 6B , the shaft 715 can include a central hole 716 through its length, thereby providing an open optical path for the optical downlink channel. Thus, the shaft 715 can be directly placed on top of the optical downlink receiver 722 that is generally located near the center of the base 710. In some embodiments, regardless of the shape of the outer circumference of the base control board 712 or the base 710, the shaft 715 defines the rotational axis 705 of the system. Therefore, the position of the shaft 715 does not have to be directly at the center of the base control board 720 or the center of the base 710.

[0165] After the shaft 715 is attached to the base control board 710, the heat dissipation element 725 can be attached to the base control board 720 by one or more screws 716. In some embodiments, the heat dissipation element 725 can be made of a material with high thermal conductivity (e.g., aluminum, etc.). Additionally, there can be one or more intermediate thermal foam pads between the heat dissipation element 725 and the board to prevent electrical short circuits while providing a heat conduction path. In some embodiments, the heat dissipation element 725 makes thermal contact with one or more portions of the lower surface of the stator board 730 and one or more portions of the upper surface of the base control board 720, thereby providing a heat path for more evenly distributing the concentrated heat of the circuit elements from these boards between the boards. At its periphery, the heat dissipation element 725 can also make thermal contact with the side of the base 710, and thus provides an improved heat path for conducting heat from the board to the base 710 and ultimately out of the system.

[0166] After fixing the heat dissipation element 725, the stator board 730 can be attached by means of screws 736. In some embodiments, the stator board 730 can be electrically connected to the base control board 720 by means of one or more multi-pin electrical connectors (e.g., lower connectors 724 and 726). In some embodiments, a physical connection between the boards is made by applying mechanical connection pressure between the stator board 730 and the base control board 720 (e.g., by pressing the stator board onto the base control board after it has been attached to the base 710). The connection pressure can be maintained during the life of the system by the screws 736 used to fix the stator board 730 to the base control board 720.

[0167] Once assembled and secured to the substrate 710, one or more optional color cameras 732 can be positioned around the perimeter of the stator plate 730 to have a transparent visual path from the substrate 710 through one or more imaging apertures 712, which in some embodiments can be transparent apertures or can contain one or more optical elements to assist with imaging. In other embodiments, the color cameras 732 can be mounted directly to the substrate 710 rather than to the stator plate 730. The color cameras 732 enable the LIDAR data accumulated by the LIDAR system to be supplemented with color imaging data such as still frames and / or video, as described in U.S. application Ser. No. 15 / 980,509, titled “Augmenting Panoramic LIDAR Results with Color,” which is incorporated herein by reference in its entirety for all purposes.

[0168] 2. Assemble the upper circuit board assembly and attach it to the lower circuit board assembly

[0169] Figure 8A is an exploded view of a compact LIDAR system 800 in accordance with some embodiments of the present disclosure to illustrate the assembly process of the LIDAR system. The LIDAR system 800 can be, for example, Figure 5A the LIDAR system 500 shown in. The LIDAR system 800 includes the lower circuit board assembly 700, the upper circuit board assembly 810, the optical ranging device 820, and the housing 830 described above with respect to Figure 7 . As Figure 8A shown, the LIDAR system 800 includes the upper circuit board assembly 8, which.

[0170] As Figure 8A shown, the upper circuit board assembly 810 has a two-board configuration similar to that described above with reference to Figure 6A , and includes a ranging device control board 840 and a rotor board 850. In some embodiments, the ranging device control board 850 and the rotor board 730 correspond to the stator control board 624 and the rotor control board 614 described above with reference to Figure 6A .

[0171] The rotor board 850 includes Figure 8B the bearing assembly 860 shown in, Figure 8B which is an exploded view of the rotor board 850. The bearing assembly 860 includes bearings 862 and 864, which are inserted into either end of a T-shaped bearing housing 865. The T-shaped bearing housing 865 can then be attached to the rotor board 850 using screws 866.

[0172] The rotor plate 850 can be placed on top of the assembled lower circuit board assembly 700 by mating the central portion of the T-shaped bearing housing 865 above the shaft 715. The circular nut 852 can then be mated to the circular central notch 854 in the top surface of the T-shaped bearing housing 86 and screwed onto the top of the shaft 715 to securely attach the rotor plate 850 to the lower circuit board assembly 700. As discussed above, due to the rotational coupling made between the shaft 715 and the bearings 862 and 864, the rotor plate 850 is capable of rotating relative to the lower circuit board assembly 700.

[0173] The ranging device control board 840 can then be engaged to the rotor plate 850 by applying a downward pressure to the ranging device control board 840. To provide an electrical connection between the ranging device control board 840 and the rotor plate 850, one or more electrical connectors can be attached (e.g., soldered) to the lower surface of the ranging device control board 840 ( Figure 8A not visible in the figure) and the upper surface of the rotor plate 850 (e.g., the connector 856). The ranging device control board 840 can then be secured to the rotor plate 850 using screws 846.

[0174] 3. Attach the laser ranging device to the rotary actuator

[0175] Once the upper circuit board assembly has been assembled and secured to the lower circuit board assembly, the optical ranging device 820 can be electrically connected to the upper surface of the ranging device control board 840, which mechanically connects the optical ranging device to the T-shaped bearing housing 865. The optical ranging device 820 includes a Tx module 822 and an Rx module 824, each of which can have a dedicated electrical connector that mates with the corresponding connectors 844 and 846 disposed on the upper surface of the optical ranging device control board 840. As with other boards in the system, connecting the optical ranging device 820 to the rest of the assembled system can be achieved by applying a pressing force to the components. Once the connection is made, the pressing force can be maintained as shown by screws 826 mounted on either side of the optical ranging device 820. Additionally, a U-shaped bracket 828 can be secured to the optical ranging device 820 using additional screws 826 to provide further structure to the assembly.

[0176] Once all the internal components are assembled, the housing 830 can be removed during the entire assembly and attached to the base 700, for example, using one or more screws and adhesives (if required), to achieve a more secure seal. The housing 830 can include an optically transparent window as described above with respect to FIG. 5, which enables the laser pulses from the Tx module 822 to be projected from the LIDAR system into the surrounding environment and enables the light reflected and scattered from the pulses to be received by the LIDAR system via the Rx module 824.

[0177] In the assembly process described above, various arrangements of screws and brackets are disclosed for purposes of illustration only. Embodiments of the compact LIDAR system do not need to employ a screw arrangement equivalent to the screw arrangement shown in Figure 7 -8, and any number, arrangement, and type of fasteners, such as adhesives, deformable pins or latches, rivets, or welds, may be used without departing from the scope of the present disclosure.

[0178] XI. Optics and Optoelectronic Components

[0179] Figures 9A - 9C Perspective, front, and scaled front views of a light ranging device 900 according to certain embodiments are shown, respectively. The light ranging device 900 may correspond to the embodiments described above with reference to FIGS. 1-6, such as the light ranging device 320 described above with reference to Figure 3 or the light ranging device 510 described with respect to FIG. 5. The light ranging device 900 includes two main modules: an optical transmission (Tx) module 910 and an optical sensing (Rx) module 920 that are spaced apart from each other within a common housing or mount 905 that includes two lens tubes, such as a transmitter lens tube 912 and a detector lens tube 922. Each of the optical Tx module and the optical Rx module includes a bulk optics module (not shown) that is positioned in front of its respective sensor / transmitter, for example, by sliding the bulk optics module into a suitable lens tube. The bulk optics module is described in more detail below. On the transmission side, behind the bulk optics module on the Tx side is (optionally) a Tx-side micro-optics assembly. Details of the micro-optics assembly are presented below with reference to Figure 10 -11. Behind the optional Tx-side micro-optics assembly is a transmitter array 914, such as an integrated single-chip NIR VSCEL array fabricated on InGaAs. On the detector side, behind the bulk optics module on the Rx side is an Rx-side micro-optics assembly, also described in more detail below with reference to Figure 10 -11. Behind the Rx-side micro-optics assembly is a single-chip detector array and ASIC combination 924, such as an integrated single-chip NIR SPAD array fabricated based on a CMOS process.

[0180] Both the Rx module 920 and the Tx module 910 are respectively backed by circuit boards 926 and 916, which contain additional support circuits for the optical ranging device, such as voltage regulators, VCSEL current drivers, etc. For example, the circuit board 926 may contain a circuit for counting signals from the SPADs to be included in a time-binned histogram, and the time binning may be specified by a time-to-digital converter. The circuit board 926 may also contain a matched filter for analyzing the histogram to determine the reception time. In some embodiments, a programmable computing element, such as an FPGA (e.g., for performing advanced filtering, such as interpolation), may be operatively connected to the Rx module 920.

[0181] Although Figures 9A - 9B not shown, the FPGA may be located on one or more of the boards of the upper board assembly of the rotary actuator described above, and the one or more boards include, for example, the rotor half of a brushless motor, the receiving side of the rotary converter power link, the receiving side of the rotary optical uplink, and the transmitting side of the rotary optical downlink. These elements together are referred to herein as the turret assembly of the LIDAR system. In certain embodiments, the turret assembly may spin at a frequency of 1 Hz to 30 Hz, thereby making range measurements at fixed angular intervals. In one embodiment, for any given full rotation (“frame”), a 64x2048 resolution depth image may be generated, but the user may select other resolutions by changing the device operating parameters. In some embodiments, the LIDAR system may acquire 2,621,440 points (range measurements) per second.

[0182] 1. Optical System for Tx and Rx Modules

[0183] Figure 10 Shows an optical block diagram of an optical ranging device 1000 according to some embodiments of the present disclosure. As Figure 10 shown, the optical ranging device 1000 includes an optical transmission (Tx) module 1010 and an optical sensing (Rx) module 1040. The optical transmission module 1010 may represent the Tx module 910, and the optical sensing module 1040 may represent the Rx module 920. Embodiments of the present disclosure are not limited to Figure 10The specific optical configuration shown in [reference]. In other embodiments, the light transmission module 1010 and the light sensing module 1040 may include fewer, more, or different optical components. Non-limiting examples of other configurations of the light transmission module 1010 and the light sensing module 1040 are set forth in the following U.S. applications: U.S. Application No. 15 / 979,235, filed May 14, 2018, entitled "Optical Imaging Transmitter with Brightness Enhancement," and U.S. Application No. 15 / 979,266, filed May 14, 2018, entitled "Spinning LIDAR Unit with Micro-optics Aligned behind Stationary Window," the disclosures of each of which are incorporated herein by reference in their entireties for all purposes.

[0184] An embodiment of the optical ranging device 1000 may be employed within the compact LIDAR system disclosed herein as described above with reference to, for example, Figures 5A - 5B The Tx module 1010 provides effective illumination of objects in the area around the LIDAR system by transmitting pulses of narrowband light, such as NIR light having a spectral width of, for example, 2 nm, 1 nm, 0.5 nm, 0.25 nm, or less, into one or more fields of view, as shown above in Figures 1A - 1B and 4. The Rx module 1040 detects the reflected portion of the transmitted narrowband light reflected by objects in the scene.

[0185] As Figure 10 shown, the Tx module 1010 may include a Tx-side micro-optics package 1020 and a bulk optical element 1030. The Tx-side micro-optics package 1020 includes a plurality of light emitters 1022 and optionally includes a microlens layer 1024 and a pore layer 1026. The emitters 1022 may be arranged in a one- or two-dimensional array of transmitter channels, such as the channels 1025 shown in the framed area. Each of the transmitter channels has one or more light emitters 1022 (such as NIR VCSELs, etc.) capable of emitting narrowband light, and optionally microlenses from the lens layer 1024 and pores from the pore layer 1026.

[0186] The light emitted from each of the transmitters diverges as it approaches one of the micro-optics in the Tx-side micro-optics lens layer 1024. The microlenses from the microlens layer 1024 capture the diverging light and refocus it onto a focal plane that coincides with the pores in the pore layer 1026, which contains a pore array whose positions correspond to the micro-optics array and the transmitter array. The pore array 1026 can reduce crosstalk in the system. After exiting the microlenses, the focused light diverges again in a conical shape and then meets the Tx-side volume imaging optics module 1030. The details of the Tx-side volume imaging optics module 1030 are discussed in more detail below.

[0187] In some embodiments, the separation between the microlens layer 1024 and the Tx-side volume imaging optics module 1030 is equal to the sum of their focal lengths, such that the light focused at the pore array 1026 appears as collimated light at the output of the Tx-side volume imaging optics module 1030, with each collimated ray bundle exiting the Tx-side volume imaging optics module 1030 at a different angle. Accordingly, the light from each transmitter is directed to a different field of view in front of the light guiding device. In some embodiments, the Tx-side volume imaging optics 1030 is on the VCSEL side of the lens, i.e., telecentric in the ray diagram of the system, and all chief rays anywhere within the pores entering the volume imaging optics 1030 travel parallel to each other out of the lens and intersect the VCSEL (image) plane at an angle of incidence that is substantially perpendicular to the VCSEL (image) plane. In this configuration, the VCSEL array advantageously acts as a telecentric source, i.e., the optics capture substantially all of the light generated by the transmitter array, even light emitted from transmitters on the outer edges of the array. Without the telecentric design, the light captured by the outer transmitters may be undesirably reduced, scattered, or refracted due to their highly oblique angles of incidence.

[0188] The Rx module 1040 includes an Rx-side volume imaging optics module 1060 and an Rx-side micro-optics package 1050. The Rx-side micro-optics package 1050 has a one-dimensional or two-dimensional array arrangement that matches the Tx-side micro-optics package 1020, with micro-optics receiver channels 1055 for each corresponding micro-optics transmitter channel 1025. The Rx-side micro-optics package 1050 includes an Rx-side pore array layer 1056, an Rx-side microlens layer 1054, a narrowband optical filter layer 1028, and a sensor array layer 1052. The portion of the emitted light that is reflected from an object in the field, shown as ray 1005, enters the Rx-side volume imaging optics module 1060 from multiple directions. The Rx-side volume imaging optics module 1060 focuses the light at a plane that coincides with the Rx-side pore array layer 1056. The focused light is then captured by the microlenses of the Rx-side microlens layer 1054 and directed in a collimated manner to the sensor array layer 1052 (i.e., with a divergence half-angle of less than ten degrees).

[0189] In some embodiments, the sensor array layer 1052 includes a 1D or 2D array of optical sensors, or a one-dimensional or two-dimensional array of groups of optical sensors such as SPADs. In some embodiments, each sensor or group of sensors in the array corresponds to a transmitter module and thus a "pixel" in the ranging data.

[0190] In some embodiments, to remove stray background light, a narrowband optical filter layer 1028 may be disposed within the layered structure, e.g., between the micro-optics array and the sensor array layer 1052. The passband of the narrowband optical filter layer 1028 may be selected to correspond to the center wavelength of the transmitter, and the width of the passband may be wide enough to accommodate any variation in the output wavelengths across the transmitter array. In some embodiments, in cases where a very narrow passband is desired, the control system may stabilize the wavelength of the transmitter individually or globally. In some embodiments, in cases where a very narrow passband is desired, the quasi-normal angle of the light passing through the filter layer 1028 must be strictly controlled such that no angle-of-incidence shift (common in thin-film interference filters) occurs; the quasi-normal angle is mainly controlled by the size of the pores in the RX-side pore array layer 1056, the focal length of the lenses in the RX-side micro-optics lens layer 1054, the relative positioning between the RX-side pore array layer 1056 and the RX-side micro-optics lens layer 1054, and the surface quality and shape accuracy of the RX-side micro-optics lens layer 1054. In some embodiments, the narrowband optical filter layer 1028 is a continuous planar layer across the entire array of sensors. In other embodiments, the narrowband optical filter layer 1028 may be fabricated as an array of micro-optical elements corresponding to the pixel geometry of the sensor array layer 1052.

[0191] Similar to the Tx side, the individual elements of the Rx module 1040 form micro-optics receiver channels such as the receiver channel 1055. According to certain embodiments, the array of micro-optics and receivers may have a layered monolithic structure. Each micro-optics receiver channel 1055 measures the light for different pixels in the sensor array layer 1052, i.e., the optics of the Rx module 1040 are used to map parallel ray bundles entering the module from different angles to different corresponding spatial positions on the sensor array layer 1052. In some embodiments, the volume imaging optics module 1060 is telecentric on the detector side of the system to avoid non-ideal factors in the image plane (in a manner similar to the TX side), as described above.

[0192] In some embodiments, a micro-optical receiver channel formed by the cooperation between, e.g., a micro-optical lens layer 1054, a narrowband optical filter layer 1028, and an Rx-side aperture array layer 1056 provides increased isolation between different pixels on a sensor array layer. This is advantageous because in some cases, e.g., when the transmitter light is reflected from a strong reflector in the field (e.g., a stop sign), the photon flux on the Rx side of each channel can be quite large, making the system sensitive to crosstalk and blurring (i.e., the incident light from one channel can be so bright that it can be detected by adjacent channels). One solution to the blurring problem is to employ a complex time-division multiplexing scheme such that only one transmitter-detector pair (or a carefully selected group of transmitter-detector pairs) is triggered at any given time, thus eliminating the risk of crosstalk. This arrangement requires additional timing electronics as well as multiplexing software and hardware, which increases the additional cost and complexity of the system. Additionally, time-division multiplexing is an inefficient data collection method because each receiver-transmitter pair must be activated sequentially in succession, thereby increasing the overall acquisition time of the array as a whole. Advantageously, the design of the Rx-side micro-optical assembly reduces crosstalk to such an extent that time-division multiplexing and sequential activation are not required, i.e., all channels can be employed simultaneously to collect data points in parallel in a manner similar to a flash LIDAR system.

[0193] The design of the micro-optical system for the Rx module 1040 and the Tx module 1010 advantageously implements the conceptual LIDAR arrangement referenced above Figure 3 described, where each transmitter element is paired with a sensor element such that the sensor element views light only from the field of view illuminated by the transmitter. This 1:1 pairing of the fields of view helps eliminate crosstalk from neighboring or adjacent pixels in the detector. The additional micro-optical aperture layer also helps eliminate crosstalk. The narrowband filter layer helps remove background light, which can contribute to spurious signal detection and ultimately produce ranging errors.

[0194] 2. Micro-Optics

[0195] Figure 11A FIG. shows a simplified top view of a micro-optical package 1100 according to certain embodiments. The micro-optical package 1100 can be applied to either or both the transmitter side or the detector side of a light ranging device and includes a plurality of channels 1102. For example, if implemented on the receiver side, each channel 1102 will correspond to a single micro-optical receiver channel, such as channel 1055. Similarly, if implemented on the transmitter side, each channel 1102 will correspond to a single transmitter channel, such as channel 1025. In the Figure 11A example shown, the micro-optical channels are arranged in an m×n interleaved array, e.g., arranged in a 16×4 array. As an example, if Figure 11Adenoting the receiver channel, then for a receiver channel size (diameter) of 0.500 mm, the illustrated layout can be implemented in a chip of size 8.000 mm by 2.000 mm.

[0196] Other array patterns are possible without departing from the scope of the present disclosure. For example, instead of a staggered array, any of the following shaped arrays may be employed: a square array, a 1D linear array (m×1), a twisted linear (m×1) array, a twisted rectangular m×n array, or an array having any arbitrary pattern. As used herein, the term "twisted" refers to an embodiment in which the spacing between receiver channels is non-uniform. For example, the receiver channels near the center are spaced closer together, while the outer channels are spaced farther apart. The twisted layout has the advantage of being able to allow correction of the distortion curve of the lens (i.e., the angles between the receiver channel fields of view are evenly spaced in the object space).

[0197] Figure 11B A cross-section of a single micro-optic receiver channel 1120 is shown, which may represent, for example, Figure 10 Receiver channel 1055 is shown in FIG. Receiver channel 1120 is used to accept an input light cone containing a wide range of wavelengths, filter out all but one narrow band of those wavelengths centered at the operating wavelength, and allow pixel (photosensor) 1171 to detect only or substantially only photons within the aforementioned narrow band of wavelengths. Embodiments of the present disclosure are not limited to any particular configuration of receiver channels, and channel 1120 is only one example of a receiver channel that can be implemented as receiver channel 1055.

[0198] In some embodiments, the receiver channel 1132 includes an input aperture layer 1140, which includes optically transparent apertures 1144 and optically opaque aperture zones 1146. The apertures 1144 are configured to define a narrow field of view when placed at the focal plane of an imaging optical element, such as a body-shaped receiving optical element 1060. As used herein, the term "optically transparent" refers to a material that allows most or all incident light to pass through. As used herein, the term "optically opaque" refers to a material that allows little or no light to pass through, such as a reflective or absorptive surface. The aperture layer 1140 is configured to receive input marginal ray lines 1133. The aperture layer 1140 may include an array of optically transparent apertures and optically opaque aperture zones constructed on a single integral piece, such as an optically transparent substrate. In some embodiments, the aperture layer 1140 may be formed of an optically opaque material that forms the aperture zone 1146, and the apertures 1144 may be holes or openings in the layer 1140.

[0199] In some embodiments, the receiver channel 1120 includes an optical lens layer 1150 that includes a collimating lens 1151 characterized by a focal length. The collimating lens may be offset from the plane of the aperture 1144 and the aperture region 1146 by the focal length and is axially aligned with the aperture 1144 (i.e., the optical axis of the collimating lens is aligned with the center of the aperture). In this way, the collimating lens may be configured to collimate light passing through the aperture such that the light travels approximately parallel to the optical axis of the collimating lens 1151. The optical lens layer 1150 may optionally include apertures, optically opaque regions, and tube structures to reduce crosstalk.

[0200] In some embodiments, the receiver channel 1132 includes an optical filter layer 1160 that includes an optical filter 1161 such as, for example, a Bragg reflector type filter. In some embodiments, the optical filter layer is disposed on the detector side of the optical lens layer 1150 (opposite the aperture side). The optical filter layer is configured to pass photons incident perpendicular thereto at a specific operating wavelength and passband. The optical filter layer 1160 may contain any number of optical filters 1161. The optical filter layer 1160 may optionally include apertures, optically opaque regions, and tube structures to reduce crosstalk.

[0201] In some embodiments, the receiver channel 1132 includes a photoelectric sensor layer 1170 including pixels 1171 disposed behind the filter layer. The pixels may be photoelectric sensors capable of detecting photons having a detector active region composed of, for example, a standard photodiode, an avalanche diode, an SPAD array, an RCP (resonant cavity photodiode), or other suitable photodetector. The photoelectric sensor 1171 may be composed of a number of photon detector regions (e.g., each a different SPAD) that cooperate together to act as a single pixel, often having a higher dynamic range, a faster response time, or other beneficial properties compared to a single large photon detection region. The photoelectric sensor layer 1170 refers to a layer composed of pixels and may include optional structures to improve detection efficiency and reduce crosstalk to adjacent receiver structures. The photoelectric sensor layer 1170 may optionally include diffusers, converging lenses, apertures, optically opaque tube spacer structures, optically opaque conical spacer structures, and the like.

[0202] Stray light may be caused by roughness of optical surfaces, defects in transparent media, back reflections, etc., and can be generated at many features within or external to the receiver channel 1132. Stray light can be directed through the filter region 1161 along a path that is not parallel to the optical axis of the collimating lens 1151; reflected between the pores 1144 and the collimating lens 1151; and generally take any other path or trajectory that may involve many reflections and refractions. If multiple receiver channels are arranged adjacent to each other, this stray light in one receiver channel can be absorbed by pixels in another channel, thereby contaminating timing, phase, or other information inherent to the photons. Accordingly, the receiver channel 1120 may also be characterized by several structures to reduce crosstalk and increase the signal between receiver channels. Examples of such structures and other suitable receiver channels are described in U.S. Patent Application 15 / 979,295, titled "Micro-optics for Imaging Module with Multiple Converging Lenses per Channel," filed on May 14, 2018, the disclosure of which is incorporated herein by reference in its entirety for all purposes.

[0203] 3. Detector array (e.g., SPAD)

[0204] Figure 12A and 12B Shows a top view of a SPAD-based photosensor array layer 1200 according to certain embodiments. Figure 12A The photosensor array layer 1200 shown in is a two-dimensional array of sensor channels 1210, where each individual sensor channel may correspond to, for example, the receiver channel 1055. Thus, each sensor channel 1210 may include a group of SPADs as described above. In Figure 12A the example shown, the photosensor array 1200 is an 18x4 array that includes a total of 72 individual sensor channels 1210. The photosensor array 1200 also includes eight calibration pixels 1220 at the top of the array. The calibration pixels 1220 may be covered, for example, by an opaque surface such that they are not exposed to any light and can therefore be used to measure dark counts.

[0205] Figure 12BAn enlarged view of a subgroup of sensor channels 1210 is shown, which shows that each sensor channel 1210 can be formed by a group (array) of individual SPADs 1212 that cooperate together to act as a single pixel. This arrangement is advantageous when the SPAD is used as a photodetector because after a photon detection event, the SPAD has a dead time during which an external circuit is used to quench the SPAD so that it is ready to detect again. Therefore, there is an upper limit to the light intensity (measured in photons / second) that a single SPAD can detect. That is, a single SPAD cannot detect a light intensity greater than one photon per quenching time. As Figure 12B shown, aggregating multiple SPADs together increases the overall intensity that can be detected because not all SPADs saturate simultaneously. Therefore, at the time of detection, the dynamic range of a collection of N SPADs can be N times that of a single SPAD.

[0206] 4. Transmitter Array (e.g., VCSEL)

[0207] Figure 13A and 13B respectively depict a simplified top view and a side view of a transmitter array 1300 according to some embodiments. The transmitter array 1300 may include a two-dimensional array of VCSEL emitters 1310 fabricated on a single monolithic chip 1305 and patterned to match the photoelectric sensor pixels on the corresponding sensor chip. In this example, the transmitter array 1300 VCSEL array is 16x4, with a total of 64 transmitter channels 1310 to match the middle 64 detector channels shown above Figure 12A in. The transmitter array 1300 may also include a plurality of wires 1320 through which signals for driving the various emitters in the array 1300 can be transmitted to the emitters.

[0208] As described with reference to Figure 12A the monolithic VCSEL array of the optical transmitter can be arranged behind the TX-side micro-optics package and behind the TX-side bulk optics module. Each VCSEL emitter may output an illumination beam having an initial diameter that is substantially equal to (or slightly larger than) the diameter of the corresponding aperture defined by the numerical aperture of the micro-lens of the pore layer or the micro-optics layer to ensure that all or substantially all of the light emitted by the VCSEL will be transmitted to the object in the field.

[0209] 5. Bulk Optics

[0210] In some embodiments, the present disclosure provides a telecentric optical ranging device having a fast lens system (e.g., f-number = 1.0, 1.2, or 1.4) and / or a lens system that is passively athermal within a specified temperature range that is likely to be encountered when the optical ranging device is used for obstacle detection and avoidance in the autonomous navigation of an automobile, truck, or other vehicle. Additionally, the body-shaped optical system has low focal plane distortion, and one or more of the optical elements may be coated with AR to maximize optical throughput and reduce stray reflections, ghost images, and crosstalk between different sensor channels. Advantageously, the optical system is image-space telecentric and thus provides a "straight-on" view (when viewed from the object side) of each of the detector channels of the sensor array (each chief ray arriving perpendicular to the focal plane), even those detector channels on the outer edges of the array.

[0211] As used herein, passively athermal describes an optical system in which the spot quality of light from an extended source having a non-zero angular size focused by the lens system onto an array does not change significantly with temperature. If the back focal length of the lens system changes and the array remains in the same position relative to the rear lens element, the spot quality of the light on the array will change. As used herein, the spot quality may be defined by the portion of light from an extended source having an angular size of 0.13 degrees focused onto an image plane and contained within a circle of 25 μm diameter. If the spot quality remains above 50% for all temperatures within a certain temperature range, the optomechanical system is considered passively athermal within that temperature range. The listed diameters and angular sizes are exemplary and depend on the size of the pores in the micro-optical array, the focal length of the system, etc.

[0212] Figure 14 A simplified schematic illustration depicting a portion of an optical module 1400 that provides a thermally stable image plane over a wide temperature range in accordance with some embodiments. The optical module 1400 includes an array 1410, a body-shaped lens system 1420, a lens housing 1430, and a mount 1440 that mechanically couples the housing to the array. The optical module 1400 may represent an embodiment of the light sensing module 330 (in which case the array 1410 may be a photoelectric sensor array) or an embodiment of the light emitting module 340 (in which case the array 1410 may be a transmitter array), and in some embodiments the mount 1440 may represent a portion of the mount 905 shown in FIG. 9. An optical ranging device in accordance with some embodiments of the present disclosure may include a first optical module 1400 as the light sensing module and a second module 1400 as the light emitting module.

[0213] The array 1410 can be planar (e.g., having less than 1 mm peak-to-valley irregularity on a 10 mm diameter wafer relative to a perfect plane) to facilitate manufacturing (e.g., forming a large number of arrays on a semiconductor substrate, where there are multiple emitters or detectors in one array). In some embodiments, the array 1410 can include micro-optical structures, such as the transmitter micro-optical package 1020 or the receiver micro-optical package 1050 discussed above with respect to Figure 10 , depending on whether the optical module 1400 is implemented as a light sensing module or a light emitting module.

[0214] As Figure 14 shown, the lens system 1420 can include a first lens 1422, a second lens 1424, a third lens 1426, and a fourth lens 1428. In some embodiments, the first lens, the second lens, the third lens, and the fourth lens are mounted in a lens housing 1430. When implemented as part of an imager sensor (i.e., the array 1410 is a photoelectric sensor array), the lens housing 1430, the lens system 1420, and the mount 1440 are configured to passively focus light from the lens system onto the photoelectric sensor array within a certain temperature range (e.g., -40 degrees Celsius to 85 degrees Celsius, -50 degrees Celsius to 95 degrees Celsius, -35 degrees Celsius to 60 degrees Celsius, -40 degrees Celsius to 105 degrees Celsius, -45 degrees Celsius to 110 degrees Celsius, or -35 degrees Celsius to 100 degrees Celsius). In embodiments that include micro-optical structures in the array, the lens system 1420 is configured to passively focus light from the lens system onto the pore layer of the micro-optical structure, and the various micro-optical components in the micro-optical structure can then focus the light received at each individual micro-optical channel onto the corresponding photoelectric sensor of that channel.

[0215] The array can be maintained at the image plane of the lens system for different temperatures. Materials can be selected to reduce cost, reduce weight, and / or maintain the image plane at the array. To reduce cost, the first lens 1422, the second lens 1424, and the fourth lens 1428 can be made of plastic (e.g., OKP-1), while the third lens 1426 can be made of glass (e.g., to reduce temperature variations in the lens system). The nominal distance between the vertex of the fourth lens and the image plane is 8 mm. In the shown lens assembly, the image plane moves towards the fourth lens as the temperature increases. This can be counterintuitive given that the refractive index of plastic decreases as the temperature increases, which would typically push the image plane away from the plastic lens because a lens with a lower refractive index will not refract light as significantly (i.e., with a longer focal length) as a convex plastic lens of similar shape with a higher refractive index (e.g., according to the Lensmaker's Equation, where the focal length is inversely proportional to the difference between the refractive indices of the lens and air, where the refractive index of air equals 1; also see Snell's Law). The combination of a glass lens and two or more plastic lenses can allow the effective focal length of the lens system to decrease as the temperature increases, but one or more of the plastic lenses in the lens system have a focal length that increases with temperature.

[0216] The lens housing 1430 (e.g., made of polycarbonate) can elongate as the temperature increases. In some embodiments, the mount 1440 is attached to the lens housing 1430 near the third lens 1426 such that the fourth lens 1428 moves to the right as the temperature of the housing increases. The material of the mount 1440 that separates the lens housing 1430 from the array 1410 expands as the temperature increases, causing the lens housing 1430 to move away from the array 1410 (e.g., to the left). At the same time, the lens housing 1430 expands as the temperature increases, causing the fourth lens 1428 to move towards (e.g., to the right) the array 1410. And, simultaneously, the back focal shift causes the image plane to move to the left as described above. By appropriately selecting the housing material CTE, the mount material CTE, and the housing-to-mount joint location, the back focal shift can be compensated for by the aforementioned housing expansion and mount expansion such that the image plane remains approximately coincident with the array within the temperature range.

[0217] In some embodiments, the mounting member 1440 may be coupled to the lens housing 1430 near the glass lens (i.e., in some embodiments, the third lens 1426). In some embodiments, the mounting member 1440 may be coupled to the lens housing 1430 near the glass lens such that as the focal length of the lens system 1420 moves relative to the array 1410 (e.g., away from the array), the lens of the lens system 1410 closest to the array 1410 (e.g., the fourth lens 1428) may move relative to the array 1410 (e.g., toward the array). In some embodiments, near may be a point or line on the outer side of the lens housing 1430, closest to the glass lens; and / or within a range of + / -5 mm or + / -10 mm from the point or line.

[0218] The spot quality of the lens system in Figure 14 was experimentally examined using the Zemax optical design program for a temperature range from -5 degrees Celsius to 70 degrees Celsius. In some embodiments, the interior of the LIDAR unit may be deliberately heated when the environment becomes lower than a specific temperature. For example, when the environment is -40 degrees Celsius, the internal components of the LIDAR unit may be heated to keep the lens system at a temperature of -5 degrees Celsius or higher. In some embodiments, the optical ranging device may include a temperature sensor and a heating element (e.g., a resistive heater) that can heat the lens system when the temperature drops below a predetermined level detected by the temperature sensor. Accordingly, it is expected that the system 1400 will work well at least for temperatures in the range from -40 degrees Celsius to 70 degrees Celsius (a temperature range of 100 degrees). In various embodiments, the system 1400 may provide a stable image plane at temperatures in the following ranges: 0 degrees Celsius to 32 degrees Celsius; 0 degrees Celsius to 55 degrees Celsius; -10 degrees Celsius to 32 degrees Celsius; -10 degrees Celsius to 55 degrees Celsius; -20 degrees Celsius to 60 degrees Celsius; -40 degrees Celsius to 85 degrees Celsius; and combinations thereof. In some embodiments, the temperature range may be from -40 degrees Celsius to 105 degrees Celsius (a temperature range of 145 degrees).

[0219] It may often be desirable to manufacture the lens housing 1430 from a material having a coefficient of thermal expansion (CTE) comparable to that of the lens to avoid pressurizing the lens. Changing the housing material may also change how the lens elements spread apart as the temperature increases. In some embodiments, the CTE of the material of the lens housing 1430 is generally not changed / tuned to prevent degradation of optical performance. Thus, the lens housing material has a CTE close to that of the lens; and not all possible materials for the housing are considered because the CTE of some housing materials is sufficiently different from that of the lens such that stress will occur in the lens, which may lead to degradation of the optical performance of the lens.

[0220] The CTE of the lens housing 1430 can be matched to the lens system 1420 within a certain temperature range such that the focal plane of the lens system 1420 is stable relative to the lens housing 1430 within the temperature range. In some embodiments, the thermal coefficient of the mount 1440 matches the thermal expansion of the lens system 1420 and / or the lens housing 1430 such that the focal plane is stable relative to the position of the detector (e.g., detector array) within the temperature range. As used herein, a focal plane is said to be "stable" within a given temperature range if the focal plane maintains a predetermined resolution at the detector of the system within a certain temperature range. As an example, in some embodiments, the predetermined resolution requires that the light focused on a point at the detector has 50% of the light within a 25-micron circle, and in other embodiments the predetermined resolution requires that the light focused on a point at the detector has 80% of the light within a 20-micron circle. The CTE of the material of the mount 1440 can be selected with the caveat that the material of the mount 1440 is strong and / or has mechanical rigidity (materials with lower CTE tend to be stronger). In this example, the fact that the back focal shift is negative (to the left) rather than positive (to the right) allows very rigid glass-filled polymers and even metals such as magnesium or aluminum to be used as the spacer material for the mount 1440.

[0221] Figure 15A 、 15B and FIGS. 15A, 15B, and 15C depict an optical module 1500 in accordance with some embodiments of the present disclosure. The optical module 1500 includes a lens system 1520 and a housing 1530 having four lenses, only two of which, lenses 1522 and 1528, are visible in Figures 15A - 15C FIG. The lens system 1520 can be, for example, the lens system 1420, and the housing 1530 can be, for example, the lens housing 1430. Since image sensors are typically not circular, the lenses of the assembly system 1500 generally do not need to be circular. For example, the photosensor array associated with the lens assembly 1500 can be narrow and tall, such that the lenses can be held in a rectangular fashion. It is generally easier and less expensive to manufacture rectangular molded polymer optics, while grinding glass lenses into a rectangular shape can be expensive. The diameter of the third lens ( Figures 15A - 15C not shown in FIG.) can define the minimum width of the lens system and thereby define a portion of the rectangular shape. By using circular glass elements and rectangular molded polymer optics, the lens assembly 1500 can be manufactured relatively easily and inexpensively.

[0222] In some embodiments, the two housings are placed as close together as possible (e.g., touching), which is another reason for keeping the glass lens (e.g., lens 3) small. For example, the optical ranging device may include a first lens system mounted in a first housing, a second lens system mounted in a second housing, a sensor array, and a transmitter array. The first lens system, the first housing, and the sensor array may form a first unit. The second lens system, the second housing, and the transmitter array may form a second unit. The first unit and the second unit may be placed side by side as close as possible (e.g., separated by no more than 2.5 cm in some embodiments and no more than 5.0 cm in other embodiments), such that light emitted from the second unit and reflected / scattered is collected by the first unit in a field of view similar to that in which the second lens system projects light from the transmitter array.

[0223] The lens system 1520 may be designed as a fast lens system. In some embodiments, the f-number of the lens system 1520 is between 1.0 and 2.4 (e.g., 1.2). The spot size on the sensor array may have 80% of the light in a 20 μm circle. Additionally, the lens system 1520 may have a footprint length equal to or less than 100 mm, 50 mm, 35 mm, and / or 20 mm and / or equal to or greater than 5, 10, 15, 20, and / or 25 mm.

[0224] In various examples, the body lens system according to the present disclosure may include: two or more plastic lenses and at least one glass lens; two or more plastic lenses; and / or one or more glass lenses. In some embodiments, a micro-optical structure may be included as part of the array as described above. The micro-optics may modify light in different ways for different transmitters and / or detectors on the array, while the body lens system modifies light for the entire array. In some embodiments, there is one or more micro-optical elements for each individual array element.

[0225] Figure 16A A top view depicting an embodiment of the optical module 1600, which may be, for example, the optical module 1500. Figure 16A Cross-section A-A is identified therein. Figure 16B An embodiment of the cross-section A-A is depicted. As Figure 16B shown, the optical module 1600 includes four optical elements, including: element 1622 (e.g., lens 1), element 1624 (e.g., lens 2), element 1626 (e.g., lens 3), and element 1628 (e.g., lens 4); and a housing 1630. Figure 16CShows an enlarged portion of cross-section A-A. The enlarged portion shows an example of how lenses 1624 and 1626 can be mounted in housing 1630. The aperture stop 1625 of the lens system 1600 is between lens 1624 and lens 1626. The aperture stop 1625 can be used to fix lens 1624 within the housing.

[0226] Figure 16D Side view depicting an embodiment of lens assembly 1600. Figure 16D Identifies cross-section B-B therein. Figure 16E Depicts an embodiment of cross-section B-B. Lenses 1, 2, 3, 4, and the housing are shown.

[0227] Figure 17A Cross-section depicting an embodiment of a first lens (lens 1522). The first lens has a first surface S1 and a second surface S2. The first surface S1 of lens 1522 and the second surface S2 of lens 1 are spherical. The first surface S1 of the first lens can be a convex surface. The second surface S2 of the first lens can be a concave surface. Light traveling from left to right can be focused by the first lens. The first surface of the first lens can be larger than the second surface of the first lens to converge the light of the lens system (e.g., reduce the f-number of the lens system).

[0228] Figure 17B Cross-section depicting an embodiment of a second lens (lens 1524). The second lens has a first surface S1 and a second surface S2. The first surface S1 of lens 1524 and the second surface S2 of lens 2 are aspherical. The first surface S1 of the second lens can be a convex surface. The second surface S2 of the second lens can be planar, slightly convex, or slightly concave. Light traveling from left to right can be defocused by the second lens.

[0229] Figure 17C Cross-section depicting an embodiment of a third lens (lens 1526). The third lens has a first surface S1 and a second surface S2. The first surface S1 of lens 1526 and the second surface S2 of lens 3 are spherical. For example, the third lens can have a width (e.g., diameter) equal to or greater than 10 mm and equal to or less than 20 mm (e.g., 11, 11.5, 12, 12.5, 13, 13.5, 14, and / or 14.5 mm). In some embodiments, the third lens is high refractive index glass. In some embodiments, the refractive index of the glass does not change within a temperature range of 100 degrees (e.g., changes by equal to or less than 0.05%). The first surface S1 of the third lens can be planar, slightly convex, or slightly concave. The second surface S2 of the third lens can be convex. Light traveling from left to right can be collimated or slightly focused by the third lens.

[0230] Figure 17DA cross-section depicting an embodiment of a fourth lens (lens 1528) is shown. The fourth lens has a first surface S1 and a second surface S2. The first surface S1 of lens 4 and the second surface S2 of lens 4 are aspherical. The first surface S1 of the fourth lens may be convex. The second surface S2 of the third lens may be convex. Light traveling from left to right may be focused onto the array.

[0231] By mixing plastic and glass lenses, and by mixing aspherical and spherical lenses, an economical, lightweight, compact, and / or athermal optical ranging device can be manufactured for autonomous vehicles.

[0232] In some embodiments, the lens system has a fixed focal length (e.g., a fixed focal length when at a constant temperature; a non-zoom lens). In some embodiments, the lens system has a fixed focal length to reduce the size, weight, number of parts, and / or complexity of the lens system.

[0233] Figure 18 An embodiment of an optical module 1800 is depicted having three lenses: a first lens 1822; a second lens 1824; and a third lens 1826. The first lens, the second lens, and the third lens are mounted in a housing 1830. A connector 1805 couples the housing to a sensor 1810 (e.g., a sensor in an array). The first lens, the second lens, and the third lens may be made of plastic (e.g., OKP-1). The first lens, the second lens, and the third lens are part of a lens system 1810. The lens system 1810 is estimated to have a focal shift of approximately 105 μm within a temperature range of 50 degrees Celsius (e.g., 0 to 50 degrees Celsius). The housing 1830 may be made of a high CTE material, and / or a mount 1840 is attached near the lens 1822 to maintain the focal plane of the lens system 1810 at the array. In Figure 18 the embodiment, polycarbonate (CTE = 70 ppm / C) is used and the mount 1840 is attached to the housing 1830, 25 - 35 mm from the array. The movement of the lenses of the lens system 1810 due to the thermal expansion of the housing 1830, the movement of the housing 1830 due to the thermal expansion of the mount 1840, and / or the combination of the focal shift of the lens system 1810 due to temperature change are matched such that the focal plane of the lens system is aligned with the array. The mount 1840 attached to the housing 30 mm from the array 1810

[0234] For purposes of illustration and description, the above description of exemplary embodiments of the invention has been presented. It is not intended to be exhaustive or to limit the invention to the precise form described, and many modifications and variations are possible in light of the above teachings. The embodiments were chosen and described in order to explain the principles of the invention and its practical application, thereby enabling others skilled in the art to utilize the invention in various embodiments and with various modifications suited to the particular purposes contemplated.

[0235] As an example, while the various embodiments and examples described above have mainly focused on the application of optical ranging within the context of 3D sensing for automotive or other road vehicle use cases, the systems disclosed herein can be used in any application without departing from the scope of the present disclosure. The smaller and even tiny form factors of the LIDAR systems according to the present disclosure enable several additional use cases, such as for solid-state optical ranging systems. As a specific example, the system can be used in 3D cameras and / or depth sensors within devices, such as mobile phones, tablet PCs, laptops, desktop PCs, or other peripheral devices and / or user interface devices. As other examples, one or more embodiments can be employed within mobile devices to support face recognition and face tracking capabilities, eye tracking capabilities, and / or 3D scanning of objects. Other use cases include forward-facing depth cameras for augmented and virtual reality applications in mobile devices.

[0236] Other applications include deploying one or more systems on airborne vehicles such as airplanes, helicopters, drones, etc. Such examples can provide 3D sensing and depth imaging to assist navigation (autonomously or otherwise) and / or generate 3D maps for later analysis, such as to support geophysical, architectural, and / or archaeological analysis. The system can also be installed on fixed objects and structures such as buildings, walls, poles, bridges, scaffolding, etc. In these cases, the system can be used to monitor outdoor areas such as manufacturing facilities, assembly lines, industrial facilities, construction sites, excavation sites, roads, railways, bridges, etc. Additionally, the system can be installed indoors and used to monitor the movement of people and / or objects within a building, such as the movement of inventory within a warehouse, or the movement of people, luggage, or merchandise within an office building, airport, train station, etc.

[0237] As another example, while the various examples above include lasers within the IR or near-IR wavelength as transmitters in LIDAR systems according to some embodiments of the present disclosure, the embodiments of the present disclosure are not limited to any specific wavelength of light or other type of radiation for the transmitter. For example, in some embodiments, the transmitter can be a laser that generates pulses having any suitable known operating wavelength, which includes the green (532 nm) wavelength that can be particularly suitable for underwater applications, or the UV wavelength that can be particularly suitable for atmospheric LIDAR systems. As will be understood by those of ordinary skill in the art who benefit from the present disclosure, many different applications of optical ranging systems are possible, and thus, the examples provided herein are for illustrative purposes only and should not be construed as limiting the use of such systems to the specifically disclosed examples.

[0238] The specific details of the specific embodiments described above can be combined in any suitable manner without departing from the spirit and scope of the embodiments of the present invention. However, other embodiments of the present invention may be directed to specific embodiments related to each individual aspect or a specific combination of these individual aspects. For example, in order to reduce the spot size on the array, more than four lenses may be used, more aspherical surfaces may be used, and / or various types of plastics may be used. As another example, in some embodiments, a curved detector and / or emitter may be used. Additionally, in some embodiments, three lenses are used instead of four (e.g., two lenses are plastic and one lens is glass). These examples and other examples are included within the scope of the present disclosure.

Claims

1. A light ranging system, comprising: A hollow shaft having a longitudinal axis extending through a central opening; A light ranging device configured to rotate about the longitudinal axis of the shaft, the light ranging device including a light source configured to transmit light pulses to an object in the surrounding environment, and a detector circuit configured to detect a reflected portion of the light pulses reflected from the object in the surrounding environment and calculate ranging data based on the reflected portion of the light pulses; A base subsystem that does not rotate about the shaft; An optical communication subsystem configured to provide an optical communication channel between the base subsystem and the light ranging device, the optical communication subsystem including one or more turntable optical communication components connected to the detector circuit and one or more base optical communication components connected to the base subsystem, wherein the one or more turntable optical communication components include an optical downlink transmitter disposed on a turntable circuit board assembly of the light ranging device and rotating about the shaft, the one or more base optical communication components include an optical downlink receiver disposed on a base circuit board assembly of the base subsystem, and the optical downlink transmitter and the optical downlink receiver are respectively positioned to transmit and receive optical signals through the central opening of the shaft, wherein the downlink channel is configured to optically transmit ranging data from the light ranging device to the base subsystem; And A wireless power system concentric with the hollow shaft and radially disposed outside the hollow shaft, the wireless power system including a ring-shaped wireless power transmitter and a ring-shaped wireless power receiver, the ring-shaped wireless power transmitter being coupled to the base subsystem and surrounding the hollow shaft, the wireless power receiver being coupled to the light ranging device at a position surrounding the hollow shaft and directly opposite the ring-shaped wireless power receiver, wherein the wall of the hollow shaft physically isolates the optical communication channel from the wireless power system.

2. The light ranging system according to claim 1, wherein the optical communication subsystem includes a downlink channel and an uplink channel, wherein the downlink channel is configured to optically transmit ranging data from the light ranging device to the base subsystem, and the uplink channel is configured to optically transmit control signals from the base subsystem to the light ranging device.

3. The light ranging system according to claim 2, wherein the uplink channel includes a plurality of optical transmitters coupled to the base subsystem and disposed outside the shaft in a ring-shaped arrangement, and a plurality of optical receivers coupled to the light ranging device and disposed outside the shaft in a ring-shaped arrangement.

4. The optical ranging system according to claim 1, wherein the optical communication subsystem is configured to optically transmit ranging data from at least one optical downlink transmitter of the one or more turret optical communication assemblies to at least one optical downlink receiver of the one or more base optical communication assemblies.

5. The optical ranging system according to claim 1, wherein: the one or more turret optical communication assemblies include an optical downlink transmitter rotatable about the shaft on a turret circuit board assembly of the optical ranging device, and the one or more base optical communication assemblies include an optical downlink receiver on a base circuit board assembly of the base subsystem, the shaft is a hollow shaft having a central opening, and the optical downlink transmitter and the optical downlink receiver are respectively positioned to transmit and receive optical signals through the central opening of the shaft.

6. The optical ranging system according to claim 1, wherein the one or more base optical communication assemblies include at least one optical uplink transmitter on a base circuit board assembly of the base subsystem, the at least one optical uplink transmitter being configured to transmit an uplink signal to the optical ranging system; and wherein the one or more turret optical communication assemblies include at least one optical uplink receiver on a turret circuit board assembly of the optical ranging device, the at least one optical uplink receiver being configured to receive the uplink signal.

7. The optical ranging system according to claim 6, wherein the at least one optical uplink transmitter includes a plurality of transmitters arranged in a first ring, and the at least one optical uplink receiver includes a plurality of receivers arranged in a second ring concentric with the first ring.

8. The optical ranging system according to claim 7, wherein the second ring is oriented in a first plane defined by the turret circuit board assembly and perpendicular to the shaft, the second ring is centered on the shaft, and the turret circuit board assembly and the base circuit board assembly are spaced apart from each other along the length of the shaft.

9. The optical ranging system according to claim 8, wherein the first ring is oriented in a second plane defined by the base circuit board assembly of the base subsystem and perpendicular to the shaft, and the first ring is centered on the shaft.

10. The optical ranging system according to claim 7, wherein the turret circuit board assembly includes a single circuit board that includes the optical downlink transmitter and the plurality of receivers.

11. The optical ranging system according to claim 7, wherein the base circuit board assembly of the base subsystem includes a single circuit board that includes the optical downlink receiver and the plurality of transmitters.

12. An optical ranging system, comprising: a housing having an optically transparent window; a hollow shaft having a longitudinal axis disposed within the housing; An optical ranging device is disposed within the housing and configured to rotate about the longitudinal axis of the shaft. The optical ranging device includes a light source configured to transmit light pulses through the optically transparent window to an object in the surrounding environment, and a detector circuit configured to detect a reflected portion of the light pulses that pass through the optically transparent window and are reflected from the object in the surrounding environment, and calculate ranging data based on the reflected portion of the light pulses; A base subsystem is disposed within the housing and does not rotate about the shaft; An optical communication subsystem is disposed within the housing and configured to provide an optical communication channel between the base subsystem and the optical ranging device. The optical communication subsystem includes a first optical channel disposed within the hollow shaft and a second optical channel annularly arranged outside the hollow shaft; And A wireless power system, the wireless power system is concentric with the hollow shaft and radially disposed outside the hollow shaft. The wireless power system includes an annular wireless power transmitter and an annular wireless power receiver. The annular wireless power transmitter is coupled to the base subsystem and surrounds the hollow shaft. The wireless power receiver is coupled to the optical ranging device at a position surrounding the hollow shaft and directly opposite to the annular wireless power receiver. Wherein the wall of the hollow shaft physically isolates the optical communication channel from the wireless power system.

13. The optical ranging system according to claim 12, wherein the first optical channel includes an optical transmitter coupled to the optical ranging device, and an optical receiver spaced apart from the optical transmitter and coupled to the base subsystem.

14. The optical ranging system according to claim 13, wherein the second optical channel includes a plurality of optical transmitters arranged at uniform intervals in an annular arrangement and configured to be coupled to a composite optical transmitter of the base subsystem, and a plurality of optical receivers arranged at uniform intervals in an annular arrangement and configured to be aligned with, spaced apart from, and coupled to a composite optical receiver of the optical ranging device.

15. The optical ranging system according to claim 14, wherein the optical ranging device further includes a first circuit board, and the base subsystem further includes a second circuit board parallel to and spaced apart from the first circuit board. Wherein the plurality of optical transmitters are disposed on the first circuit board, and the plurality of optical receivers are disposed on the second circuit board.

16. The optical ranging system according to claim 15, wherein each of the optical transmitters among the plurality of optical transmitters includes an LED, and each of the optical receivers among the plurality of optical receivers includes a photodiode.

17. The optical ranging system according to any one of claims 12 to 16, wherein the first optical channel is configured to transmit ranging data from the optical ranging device to the base subsystem, and the second optical channel is configured to transmit control signals from the base subsystem to the optical ranging device.

18. A light ranging system, comprising: A housing having an optically transparent window; A hollow shaft having a longitudinal axis disposed within the housing; A light ranging device disposed within the housing and configured to rotate about the longitudinal axis of the shaft, the light ranging device including a light source configured to transmit light pulses through the optically transparent window to an object in the surrounding environment, and a detector circuit configured to detect a reflected portion of the light pulses that pass through the optically transparent window and are reflected from the object in the surrounding environment, and to calculate ranging data based on the reflected portion of the light pulses; A base subsystem disposed within the housing and not rotating about the shaft; A first optical communication channel configured to optically transmit data between the light ranging device and the base subsystem via the hollow shaft, the first optical communication channel including a first optical component coupled to a circuit configured to rotate with the light ranging device, and a second optical component coupled to a circuit disposed on the base subsystem; A second optical communication channel disposed around the hollow shaft and configured to optically transmit data between the light ranging device and the base subsystem, the second optical communication channel including a first annular optical component coupled to a circuit configured to rotate with the light ranging device, and a second annular optical component coupled to a circuit disposed on the base subsystem; And A wireless power system concentric with the hollow shaft and radially disposed outside the hollow shaft, the wireless power system including an annular wireless power transmitter and an annular wireless power receiver, the annular wireless power transmitter coupled to the base subsystem and surrounding the hollow shaft, the wireless power receiver coupled to the light ranging device at a position surrounding the hollow shaft and directly opposite the annular wireless power receiver, wherein the wall of the hollow shaft physically isolates the first optical communication channel from the wireless power system.

19. The light ranging system according to claim 18, wherein the first optical communication channel is a downlink channel configured to transmit ranging data from the light ranging device to a processor coupled to the base subsystem, and the second optical communication channel is an uplink channel configured to transmit control signals from the processor to the light ranging device, and wherein the wall of the hollow shaft provides optical isolation between the downlink channel and the uplink channel.

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