INTEGRATED TX/RX AND SCANNER MODULE

Embodiments of the disclosure provide optical sensing systems, optical sensing methods, and integrated transmitter-receiver-scanner (TX-RX-scanner) modules. An exemplary optical sensing system includes an integrated TX-RX-scanner module and a printed circuit board coupled to the integrated TX-RX-scanner module. The integrated TX-RX-scanner module includes a plurality of optical components optically aligned with each other and a plurality of pins located on edges of the TX-RX-scanner module. The printed circuit board is separated from and connected to the integrated TX-RX-scanner module, and includes one or more serving electronic components connected to the optical components through the plurality of pins located on the edges of the integrated TX-RX-scanner module.

TECHNICAL FIELD

The present disclosure relates to a light detection and ranging (LiDAR) system, and more particularly to, an integrated transmitter-receiver-scanner module in a LiDAR system.

BACKGROUND

In a typical coaxial LiDAR system, a laser signal (pulsed or continuous wave) is delivered through transmitting optics (hereinafter referred to as “TX”). After hitting an object in the environment, the laser signal is bounced back (becoming a reflected laser signal) and re-directed onto a detection arm (hereinafter referred to as “RX”), typically via a beam splitter. Next, the reflected laser signal is collected by a photodetector of the detection arm. In practical applications, it is desirable to have a LiDAR system with a smaller size. Current LiDAR systems generally have a size of about 14 cm×14 cm×10 cm, which is still large. To reduce the size of a LiDAR system without affecting the alignment and integration of different components in the system becomes quite challenging in existing LiDAR systems. In the existing LIDAR systems, different components are sitting separately in position, and many of these components (e.g., laser source, detector, scanner) require individual packaging, which makes these components difficult to align accurately and efficiently due to the size, weight, and complexity of each component. Considering that the sizes of the laser source and the photodetector are often on the order of a few tens of micrometers to a few hundreds of micrometers, it is very challenging to achieve, at the component level, high-accuracy mechanical alignment, which itself is crucial to the overall performance and cost for the manufacturing of these LiDAR systems. In addition, due to the individual placements of the TX, RX, and scanner modules, it is difficult to further reduce the overall size of existing LiDAR systems without affecting the complexity of alignment of different components within these LiDAR systems.

Embodiments of the disclosure address the above problems by integrating optical components of a LiDAR system in a single package, to form an integrated TX-RX-scanner module.

SUMMARY

In one example, embodiments of the disclosure provide an optical sensing system. The optical sensing system may include an integrated transmitter-receiver-scanner (TX-RX-scanner) module comprising a plurality of optical components optically aligned with each other and a plurality of pins located on edges of the TX-RX-scanner module. The optical sensing system further includes a printed circuit board separated from and connected to the integrated TX-RX-scanner module, where the printed circuit board includes one or more serving electronic components connected to the optical components through the plurality of pins located on the edges of the integrated TX-RX-scanner module.

In another example, embodiments of the disclosure provide an integrated TX-RX-scanner module. The integrated TX-RX-scanner module includes a plurality of optical components optically aligned with each other. The integrated TX-RX-scanner module further includes a plurality of pins located on edges of the TX-RX-scanner module, where the plurality of pins are connected to one or more of the optical components on one end, and are connectable, one the other end, to one or more serving electronic components outside the integrated TX-RX-scanner module, or to one or more monitoring devices for aligning the optical components included in the integrated TX-RX-scanner module.

In a further example, embodiments of the disclosure provide a method for forming an optical sensing system. The method includes assembling an integrated TX-RX-scanner module, where the integrated TX-RX-scanner module includes a plurality of optical components optically aligned with each other and a plurality of pins located on edges of the TX-RX-scanner module. The method further includes assembling a printed circuit board coupled to the integrated TX-RX-scanner module, where the printed circuit board includes one or more serving electronic components connectable to the optical components through the plurality of pins located on the edges of the integrated TX-RX-scanner module. The method additionally includes connecting the one or more serving electronic components with the integrated TX-RX-scanner module through the plurality of pins disposed on the edges of the integrated TX-RX-scanner module, to form the optical sensing system containing the integrated TX-RX-scanner module.

DETAILED DESCRIPTION

Embodiments of the present disclosure provide integration of several LiDAR components in a single package that can be sealed or even hermetically sealed. The integrated LiDAR components may be disposed on a same substrate and sealed inside a same package as a single module. According to one example, this single module excludes most active components that are not required for alignment of components in a LiDAR system that are in the light path of the laser beams. The excluded active components may include certain serving electronic components such as signal processing field programmable gate array (FPGA), printed circuit boards (PCBs) for power electronics, readout circuits, and the like. These components usually do not require alignment and their positioning does not impact the light path. The single module may merely include optical components such as various optics and laser strip, detector array, and MEMS scanner, and the coupled driving circuits such as laser driver, MEMS driver, and detector driver. In addition, certain peripheral input/output (I/O) ports may be also integrated into the module. These I/O ports may be configured for setting up connection/communication of certain optical components (such as laser strip, detector array, and MEMS scanner) with other serving electronic components, such as FPGA, readout circuit, and power electronic PCBs, located outside the module. Accordingly, the module may be kept to a compact size (e.g., around 10 cm×6 cm, which is much smaller than other existing LiDAR systems) by keeping the included components at a low profile. Due to the exclusion of certain non-essential active components and the complexity brought by these components, the alignment process required for aligning the optical components included in the module may be simplified.

Other advantages of the disclosed LiDAR system include that the integrated TX-RX-scanner module eliminates the need for individually packaging each key sensitive device, such as the laser and detector dies. In addition, alignment accuracy within a single package can be improved due to pre-alignment as well as the close distance among relevant components inside a same package (e.g., all the elements in the TX-RX-scanner module may be packed together in a package). Furthermore, the disclosed TX-RX-scanner module may be hermetically sealed, and thus the environmental changes such as humidity change that normally cause optics contamination can be prevented. The features and advantages described herein are exemplary and not all-inclusive.

The disclosed LiDAR system with an integrated TX-RX-scanner module can be used in many applications. For example, the disclosed LiDAR system can be used in advanced navigation technologies, such as to aid autonomous driving or to generate high-definition maps, in which the disclosed LiDAR system can be used as an optical sensing system equipped on a vehicle.

FIG.1illustrates a schematic diagram of an exemplary vehicle equipped with an optical sensing system containing an integrated TX-RX-scanner module, according to embodiments of the disclosure. Consistent with some embodiments, vehicle100may be a survey vehicle configured for acquiring data for constructing a high-definition map or 3-D buildings and city modeling. Vehicle100may also be an autonomous driving vehicle.

As illustrated inFIG.1, vehicle100may be equipped with an optical sensing system (e.g., a LiDAR system)102(also referred to as “LiDAR system102” hereinafter) mounted to a body104via a mounting structure108. Mounting structure108may be an electro-mechanical device installed or otherwise attached to body104of vehicle100. In some embodiments of the present disclosure, mounting structure108may use screws, adhesives, or another mounting mechanism. Vehicle100may be additionally equipped with a sensor110inside or outside body104using any suitable mounting mechanisms. Sensor110may include sensors used in a navigation unit, such as a Global Positioning System (GPS) receiver and one or more Inertial Measurement Unit (IMU) sensors. It is contemplated that the manners in which LiDAR system102or sensor110can be equipped on vehicle100are not limited by the example shown inFIG.1and may be modified depending on the types of LiDAR system102and sensor110and/or vehicle100to achieve desirable 3D sensing performance.

Consistent with some embodiments, LiDAR system102and sensor110may be configured to capture data as vehicle100moves along a trajectory. For example, a transmitter of LiDAR system102may be configured to scan the surrounding environment. LiDAR system102measures distance to a target by illuminating the target with laser beams and measuring the reflected/scattered laser signals with a receiver. The laser beams used for LiDAR system102may be ultraviolet, visible, or near-infrared, and may be pulsed or continuous wave laser beams. In some embodiments of the present disclosure, LiDAR system102may capture point clouds including depth information of the objects in the surrounding environment, which may be used for constructing a high-definition map or 3-D buildings and city modeling. As vehicle100moves along the trajectory, LiDAR system102may continuously capture data including the depth information of the surrounding objects (such as moving vehicles, buildings, road signs, pedestrians, etc.) for map, building, or city modeling construction.

FIG.2illustrates a block diagram of an exemplary LiDAR system containing an integrated TX-RX-scanner module, according to embodiments of the disclosure. In some embodiments, LiDAR system102may be a biaxial LiDAR, a semi-coaxial LiDAR, a coaxial LiDAR, a scanning flash LiDAR, etc. As illustrated, LiDAR system102may include a transmitter202, a receiver204, and a controller206coupled to transmitter202and receiver204. Transmitter202may further include a laser emitter208for emitting a laser beam207, and one or more optics210for collimating laser beam207emitted by laser emitter208. In some embodiments, transmitter202may additionally include a scanner212for steering the collimated laser beam209according to a certain pattern. Transmitter202may emit optical beams (e.g., pulsed laser beams, continuous wave (CW) beams, frequency modulated continuous wave (FMCW) beams) along multiple directions. Receiver204may further include a receiving lens216, a photodetector218, and a readout circuit220. Although not shown, in some embodiments, LiDAR system102may further include other optical components. For instance, LiDAR system102may additionally include a beam splitter for separating returned laser beams from laser beams emitted by laser emitter208in a coaxial LiDAR system.

Laser emitter208may be configured to provide laser beams207(also referred to as “native laser beams”) to optics210. For instance, laser emitter208may generate laser beams in the ultraviolet, visible, or near-infrared wavelength range, and provide the generated laser beams to optics210. In some embodiments of the disclosure, depending on underlying laser technology used for generating laser beams, laser emitter208may include one or more of a double heterostructure (DH) laser emitter, a quantum well laser emitter, a quantum cascade laser emitter, an interband cascade (ICL) laser emitter, a separate confinement heterostructure (SCH) laser emitter, a distributed Bragg reflector (DBR) laser emitter, a distributed feedback (DFB) laser emitter, a vertical-cavity surface-emitting laser (VCSEL) emitter, a vertical-external-cavity surface-emitting laser (VECSEL) emitter, an extern-cavity diode laser emitter, etc., or any combination thereof. Depending on the number of laser emitting units in a package, laser emitter208may include a single emitter containing a single light-emitting unit, a multi-emitter unit containing multiple single emitters packaged in a single chip, an emitter array or laser diode bar containing multiple (e.g., 10, 20, 30, 40, 50, etc.) single emitters in a single substrate, an emitter stack containing multiple laser diode bars or emitter arrays vertically and/or horizontally built up in a single package, etc., or any combination thereof. Depending on the operating time, laser emitter208may include one or more of a pulsed laser diode (PLD), a CW laser diode, a Quasi-CW laser diode, etc., or any combination thereof. Depending on the semiconductor materials of diodes in laser emitter208, the wavelength of emitted laser beams207may be at different values, such as 760 nm, 785 nm, 708 nm, 848 nm, 870 nm, 905 nm, 940 nm, 980 nm, 1064 nm, 1083 nm, 1310 nm, 1370 nm, 1480 nm, 1512 nm, 1550 nm, 1625 nm, 1654 nm, 1877 nm, 1940 nm, 2000 nm, etc. It is understood that any suitable laser source may be used as laser emitter208for emitting laser beams207at a proper wavelength.

Optics210may include one or more optics that are configured to shape a laser beam, for example, to collimate a laser beam into a narrow laser beam209to increase the scanning resolution and the range to scan object(s)214. Scanner212may include various optical elements such as prisms, mirrors, gratings, optical phased array (e.g., liquid crystal-controlled grating), or any combination thereof. In some embodiments, object(s)214may be made of a wide range of materials including, for example, non-metallic objects, rocks, rain, chemical compounds, aerosols, clouds, and even single molecules. In some embodiments, at each time point during a scanning process, scanner212may direct laser beams211to object214in a direction within a range of scanning angles by rotating a deflector, such as a micromachined mirror assembly.

Receiver204may be configured to detect laser beams213returned from object214. Upon contact, laser light211emitted by transmitter202can be reflected/scattered by object214via backscattering. Returned laser beams213may be in a same or different direction from laser beams211. In some embodiments, receiver204may collect laser beams returned from object214and output signals reflecting the intensity of the returned laser beams.

As illustrated inFIG.2, receiver204may include a receiving lens216, a photodetector218, and a readout circuit220. Receiving lens216may be configured to collect light from a respective direction in a receiver field-of-view (FOV) and converge the returned laser beams213to focus on photodetector218. At each time point during a scanning process, returned laser beams213may be collected by receiving lens216. Laser beams213may be returned from object(s)214. The pulses in returned laser beam213may have the same waveform (e.g., bandwidth and wavelength) as those in laser beams211.

Photodetector218may be configured to detect laser beams213returned from object214and converged by receiving lens216. In some embodiments, photodetector218may convert the laser light (e.g., laser beams215) converged by receiving lens216into an electrical signal219(e.g., a current or a voltage signal). Electrical signal219may be an analog signal, which is generated when photons are absorbed in a photodiode included in photodetector218. In some embodiments, photodetector218may include a PIN (p-type, intrinsic, n-type) detector, an avalanche photodiode (APD) detector, a single photon avalanche diode (SPAD) detector, a silicon photo multiplier (SiPM) detector, or the like.

Readout circuit220may be configured to integrate, amplify, filter, and/or multiplex signal detected by photodetector218and transfer the integrated, amplified, filtered, and/or multiplexed signal onto output parts (e.g., controller206) for further processing. In some embodiments, readout circuit220may act as an interface between photodetector218and the signal processing unit (e.g., controller206). Depending on the configurations, readout circuit220may include one or more of a transimpedance amplifier (TIA), an analog-to-digital converter (ADC), a time-to-digital converter (TDC), and the like.

Controller206may be configured to control transmitter202and/or receiver204to perform detection/sensing operations. For instance, controller206may control laser emitter208to emit laser beams207, or control photodetector218to detect optical signals returned from the environment. In some embodiments, controller206may also be implemented to perform data acquisition and analysis functions. For instance, controller206may collect digitalized signal information from readout circuit220, determine the distance of object(s)214from LiDAR system102according to the travel time of laser beams, and construct a high-definition map or 3-D buildings and city modeling surrounding LiDAR system102based on the distance information of object(s)214.

It should be understood thatFIG.2merely illustrates a block diagram of different functional components within LiDAR system102. In real applications, these functional components can be organized in different shapes, structures, or configurations. For instance, as previously described and as further described in detail below, to facilitate the alignment process of a LiDAR system and to reduce the overall size of a LiDAR system, certain components may be integrated into a single module and sealed in a single package, but not packaged separately as different transmitter, receiver, and controller modules. For example, optical components that require alignment to form the light path may be integrated into a single package, to form a TX-RX-scanner module, as further described more in detail inFIGS.3-5.

FIG.3illustrates a simulation diagram of an exemplary integrated TX-RX-scanner module, according to embodiments of the disclosure. As illustrated inFIG.3, an integrated TX-RX-scanner module301may include a substrate302and certain optical components fixed onto substrate302. The optical components may include various components that are essential for the alignment of the optical components included in a LiDAR system. For instance, the optical components may include transmitting and receiving components that emit laser beams and receive or detect laser beams returned from the environment. For example, as illustrated inFIG.3, the optical components may include a laser strip304(e.g., a laser diode or a set of laser diodes aligned in a one-dimensional, two-dimensional array, or three-dimensional array) that emits laser beams, and a photodetector306(e.g., a photosensor or a set of photosensors aligned in a one-dimensional, two-dimensional, or three-dimensional array) that senses or detects the laser beams returned from the environment during a sensing process by LiDAR system102. In some embodiments, the optical components may further include a scanner308for directing the emitted laser beams towards the environment. Although not shown, the optical components may additionally include certain driving circuits coupled to the optical components, such as a laser driver, receiver driver, and scanner driver, etc.

Although not shown inFIG.3, the integrated TX-RX-scanner module301may further include various optics, such as optical lens, prisms, mirrors, or any combination thereof, for collimating, reflecting, diffracting, collecting, converging optical signals during the operation of a LiDAR system. In one example, the optics inside a TX-RX-scanner module301may include one or more collimating lens (e.g., fast axis collimator lens, slow axis collimator lens), a beam splitter, a receiving lens, and the like. In some embodiments, these optics may be aligned with the transmitting, receiving, and scanning optical components, such as components304,306, and308, before being fixed onto substrate302to form an integrated TX-RX-scanner module301.

As previously described, to reduce the overall size of TX-RX-scanner module301and to simplify the alignment process, certain serving electronic components may be excluded from TX-RX-scanner module301. For instance, for a LiDAR system102, except the optical components such as the various optics and the laser strip, laser detector array, and MEMS scanner, the serving electronic components may not be included in the disclosed TX-RX-scanner module301. These serving electronic components may include FPGA, readout circuits, and power electronic PCBs that can be separated from the optical components and the coupled driving circuits. For instance, for the transmitter of a LiDAR system, besides the laser diode(s) and the coupled driving circuit, other serving electronic components such as the power supply may be excluded from the integrated TX-RX-scanner module301. Similarly, for the receiver of a LiDAR system, besides photosensors or photosensor array and the coupled detector driver, other serving electronic components such as the readout circuit and the power electronics may be also excluded from the integrated TX-RX-scanner module301. For the scanning device of a LiDAR system, depending on the configurations (e.g., various one-dimensional or two-dimensional scanning), the components included in TX-RX-scanner module301may be different. However, in general, a platform that actuates the motion of a scanning mirror or reflector of the scanner and a driver/driving circuit for driving the motion of the platform may be included in TX-RX-scanner module301, while other serving electronic components, such as power electronics and controller(s) for providing the instructions to the driver and/or the actuation platform may be excluded from TX-RX-scanner module301.

In some embodiments, by excluding these serving electronic components from the disclosed TX-RX-scanner module301, the integrated TX-RX-scanner module301can be made compact. This then reduces the overall size of a LiDAR system. In some embodiments, these excluded serving electronic components can be separately packaged, for example, into a single PCB that can also be made compact and/or fit to the shape and structure of the integrated TX-RX-scanner module301. For instance, the as-formed integrated PCB containing the excluded serving electronic components may be disposed in space (e.g., a corner as indicated by arrow303inFIG.3) surrounding TX-RX-scanner module301.

In some embodiments, the excluded serving electronic components may be connected with the optical components and/or coupled drivers through certain pins located on the edges of TX-RX-scanner module301. For instance, there may be a certain number of pins for each of the optical components304,306, and308located on the edges of TX-RX-scanner module301.

In some embodiments, there may be additional pins for certain optics included in the integrated TX-RX-scanner module301. For instance, certain controllable and/or adjustable optical lenses (e.g., Alvarez lens for adjusting the divergence of emitted laser beams) may be included in TX-RX-scanner module301. These controllable and/or adjustable optical lenses may also have corresponding pins located on the edge(s) of TX-RX-scanner module301for setting up signal communication with the serving electronic components (e.g., controllers for controlling the adjustable optical components).

By including these pins on the edges of the integrated TX-RX-scanner module301, an already aligned and packaged TX-RX-scanner module301may be made functional by just connecting the pins with the respective serving electronic components outside the package, without further moving or adjusting any component inside the package of the integrated TX-RX-scanner module301after packaging. This then allows the integrated TX-RX-scanner module301to be manufactured and shipped to customers/suppliers as a stand-alone package without the serving electronic components, thereby facilitating the mass production of the integrated TX-RX-scanner modules.

In some embodiments, before fixing the optical components included in the integrated TX-RX-scanner module301, various alignments may be performed first, as previously described. In one example, fast axis collimator lens and slow axis collimator lens may be aligned with the laser strip, scanning mirror or reflector may be aligned with the laser strip and/or the fast axis collimator lens and slow axis collimator lens, the beam splitter may be aligned with the scanning mirror to reflect returning laser beams to the receiver, collecting lens may be aligned with the beam splitter and/or photosensor(s) in the receiver, and so on. These different alignments may be performed independently according to a predefined order, to ensure the full alignment of the various elements included in the TX-RX-scanner module.

In some embodiments, a large number of TX-RX-scanner modules301may be aligned under a uniform alignment setting. For instance, the setting may include one or more monitoring devices that can be connected to the optical components (e.g., through connecting to the pins located on the edges of TX-RX-scanner modules301), to drive the optical components. According to one embodiment, the setting may include certain power supplies for powering the optical components and certain controllers for controlling the operation of these optical components. In some embodiments, other devices facilitating the alignment processes may be also included in the setting. For instance, certain camera(s) or sensor(s) for signal detection and certain reference retroflector(s) for directing the optical signals may be included in the setting to facilitate the various alignment processes.

In some embodiments, by preparing such an alignment setting, a plurality of TX-RX-scanner modules301may be aligned by using the same setting, thereby facilitating the mass production of TX-RX-scanner modules301and reducing the alignment cost required for a LiDAR system. To allow each TX-RX-scanner module to align, each TX-RX-scanner module may be connected to the monitoring devices through a subset of pins located on the edges of the TX-RX-scanner module. That is, instead of connecting to each respective serving electronic component of a LiDAR system for alignment, a disclosed TX-RX-scanner module may be aligned without the presence of such serving electronic components in an actual LiDAR system. This then simplifies the alignment process, thereby reducing the alignment cost and facilitating the mass production of disclosed TX-RX-scanner modules.

After the alignment, the optical components may be fixed onto a same substrate302. In some embodiments, to prevent alignment drifting (e.g., the position and/or orientation change of aligned components after the alignment), quick and efficient fixing mechanisms (e.g., fluid dispensing) may be applied, so that the optical components can be fixed onto substrate302in a short period of time after the alignment.

In some embodiments, to prevent alignment from drifting due to environmental change after fixing to substrate302, certain low-thermal-expansion materials may be used for the construction of substrate302. These low-thermal expansion materials may include certain fine ceramics, such as silicon nitride, aluminum nitride, aluminum oxide, silicon carbide, etc. The low-thermal expansion materials may display little dimension change with changes in temperature, and thus, if used in substrate302, may greatly reduce system-level alignment drift caused by thermal expansion. In some embodiments, other types of materials/structures may also be used in constructing substrate302. For instance, a certain type of PCB may be also used to construct substrate302that supports the optical components and holds these components together.

In some embodiments, after fixing the optical components, TX-RX-scanner module301may be hermetically sealed. By sealing TX-RX-scanner module301hermetically, environment changes such as humidity change that normally cause optics contamination can be prevented. In some embodiments, hermetical sealing of integrated TX-RX-scanner module301may include the formation of an airtight package that prevents the passage of gases between the inside and outside of the package. In some embodiments, hermetically sealing of integrated TX-RX-scanner module301may include removal or exchange of air (e.g., with nitrogen) inside the package of integrated TX-RX-scanner module301.

In some embodiments, to allow laser beams to be directed towards the environment outside the package, the hermetically sealed package of integrated TX-RX-scanner module301may include a glass window for light passage. That is, emitted laser beams may pass through such a glass window of the hermetically sealed package, to reach object(s) in the surrounding of a LiDAR system. In some embodiments, when returned laser beams are in a different direction from emitted laser beams (e.g., in a biaxial LiDAR system), an optical filter may be used in lieu of glass in the glass window, to help filter out any ambient light that has a wavelength different than the laser wavelength. This helps reduce ambient light noise and thus improves the performance of a LiDAR system.

It is to be noted, the above-described components inside a TX-RX-scanner module301are merely for illustrative purposes, and not for limitation. In some embodiments, a TX-RX-scanner module301may include more or fewer components than those described above. For instance, a TX-RX-scanner module301may additionally include certain sensors for facilitating the operation of the disclosed TX-RX-scanner module in a LiDAR system. In one example, a thermometer for monitoring the environmental change may be included in a TX-RX-scanner module, to prevent overheat of the disclosed TX-RX-scanner module in a LiDAR system. Additional information (e.g., pins and bonding wires) about the disclosed TX-RX-scanner module are further described in detail inFIG.4.

FIG.4illustrates a schematic diagram of an exemplary TX-RX-scanner module401, according to embodiments of the disclosure. As illustrated, the disclosed TX-RX-scanner module401may include a substrate403for hosting optical components inside a package405. On the sidewall of package405, there are multiple sets of pins that are connected to the optical components inside package405. For instance, there is one set of pins426aconnecting to a laser strip402, another set of pins426bconnecting to a photosensor or photosensor array422, and a third set of pins426cconnecting to a MEMS-driven scanning mirror or reflector412. These pins may be connected to the respective optical components and/or their drivers through one or more bonding wires set up for signal transmission.

Inside package405, different optical components may be disposed in a pattern following the general organization of components inside a LiDAR system. For instance, as shown inFIG.4, laser strip402may be disposed on one end of package405, while a scanning mirror or reflector412is disposed on another end of package405. Along the light path from laser strip402to the scanning mirror or reflector412, a set of collimator lenses (e.g., a fast axis collimator lens406and a slow axis collimator lens408) may be sequentially disposed, which are followed by a beam splitter410. On a third end of package405, a photosensor or photosensor array422may be disposed. Right before photosensor (or photosensor array)422along the light path, a receiving lens418may be disposed, which is configured to focus the returning laser beams onto photosensor or photosensor array422. In some embodiments, a window416may be further arranged on a sidewall of TX-RX-scanner module401, for example, on one sidewall of package405. Window416may allow laser beams to pass through package405. In some embodiments, package405itself may be a non-transparent package (except window416) configured to limit the ambient light.

As previously described, the different optical components or optics (e.g.,406,408,410, and418) may be pre-aligned before fixing to substrate403. For instance, fast axis collimator lens406and slow axis collimator lens408may be pre-aligned with laser strip402. Receiving lens418may be pre-aligned with photosensor (or photosensor array)422. Beam splitter410may be pre-aligned with laser strip402, scanning mirror or reflector412, and photosensor (or photosensor array)422. Scanning mirror or reflector412may be also aligned with fast axis collimator lens406and slow axis collimator lens408. Other alignments are also possible. In some embodiments, active alignment technology may be employed in the alignment of these different optical components inside package405.

It is to be noted that the disclosed TX-RX-scanner module401is merely for illustrative purposes, and not for limitation. In some embodiments, a TX-RX-scanner module401may include more or fewer components than those illustrated inFIG.4. For instance, depending on the configuration of a LiDAR system, a TX-RX-scanner module401may include a set of Alvarez lenses for tuning emitted laser beams. For another instance, a beam splitter may not be included in a TX-RX-scanner module if a LiDAR system102is a biaxial LiDAR system. Additionally, in some embodiments, the optical components402,412, and422may be connectable to the respective serving electronic components of a LiDAR system through the pins426a-426c, as further illustrated in detail inFIG.5.

FIG.5illustrates a schematic diagram of an exemplary LiDAR system containing a TX-RX-scanner module401and a coupled PCB501, according to embodiments of the disclosure. As illustrated, besides TX-RX-scanner module401, a LiDAR system may further include a PCB501that holds the serving electronic components503a,505b, . . . ,503n(together or individually may be referred to as serving electronic component503) for different optical components inside TX-RX-scanner module401. These serving electronic components503may be integrated into a same PCB board to save the space and/or manufacturing cost. In addition, these serving electronic components may be connectable to the respective optical components (e.g.,402,412, and422) illustrated inFIG.4, and to other controllable and/or adjustable optics, through pins and flexible bonding wires (e.g., bonding wires505a, . . . ,505nillustrated in FIG.5). To set up such connections, PCB board501may also include certain pins or other types of I/O ports, which then allow a connection between PCB board501and the coupled TX-RX-scanner module401.

In some embodiments, the serving electronic components503a-503nmay include power electronics for each of the optical components (e.g.,402,412, and422) and/or for other adjustable or controllable optics. In addition, the serving electronic components may include various FPGA elements. For instance, controller206of a LiDAR system102may be an FPGA element integrated into PCB501. For another instance, another controller for controlling the motion of a MEMS scanner in a LiDAR system may be a separate FPGA element, or may be incorporated into the same FPGA element for controller206as described above. In some embodiments, certain other serving electronic components, such as readout circuits, that facilitate the operation of a LiDAR system may also be possible and be integrated into PCB501.

It is to be noted that PCB501is not necessarily one single piece, but can include multiple pieces that are disposed in a same or separate places around a TX-RX-scanner module401. By configuring multiple pieces of PCBs, it may facilitate the distribution of the PCB board(s) around TX-RX-scanner module401. For instance, two pieces of PCBs may be separately disposed on the left corner and right corner, as indicated by arrows507aand507b, which then reduces the overall size of a LiDAR system. In addition, by including multiple pieces of PCB board, each piece may be disposed in a convenient location to allow the included serving electronic components to be close to the corresponding optical components, thereby shortening the bonding wires used for signal transmission. This can improve the signal-to-noise ratio during the signal transmission process due to the shorter wires used for signal transmission.

As can be seen fromFIG.5and as previously described, since a TX-RX-scanner module can be pre-aligned and mass-produced, a disclosed LiDAR system102may be assembled in a way different from other existing LiDAR systems that organize different transmitter, receiver, and scanner as individual modules. That is, instead of assembling the individual transmitter, receiver, scanner, and the relevant optics, the disclosed LiDAR system is formed by assembling an integrated TX-RX-scanner module with a PCB(s) containing remaining serving electronic components. These serving electronic components may include certain components that are generally considered part of the transmitter, receiver, and scanner in other existing LiDAR systems, such as power electronics for each transmitter, receiver, and scanner, etc. However, in the disclosed embodiments, these serving electronic components are separate from the respective optical components in the LiDAR system, to simplify the alignment process/cost and reduce the overall size of the disclosed LiDAR system.

FIG.6illustrates a flow chart of an exemplary method600for forming a LiDAR system containing a TX-RX-scanner module, according to embodiments of the disclosure. In some embodiments, method600may include steps S602-S606. It is to be appreciated that some of the steps may be optional. Further, some of the steps may be performed simultaneously, or in a different order than that shown inFIG.6.

In step S602, an integrated TX-RX-scanner module is generated, where the integrated TX-RX-scanner module may include a plurality of optical components. For instance, as described inFIGS.4-5, multiple optical components, such as laser strip, photosensor array, MEMS scanner, including the corresponding drivers, may be included inside an integrated TX-RX-scanner module. In addition, various other optics, such as collimator lens, receiving lens, and beam splitter, may be also included in the formed TX-RX-scanner module. These optical components may be pre-aligned with each other and then fixed onto a same substrate inside the TX-RX-scanner module. The TX-RX-scanner module may be then sealed (e.g., hermetically sealed) inside a chamber as a package.

As also described inFIGS.4-5, on the edges (e.g., on the sidewalls) of the TX-RX-scanner module, multiple pins may be included to set up a connection between the TX-RX-scanner module and other serving electronic components supporting the functions of the optical components inside the TX-RX-scanner module. These pins may run across the sidewalls of the TX-RX-scanner module and may be pre-connected to the respective optical components inside the TX-RX-scanner module (e.g., through bonding wires) before the package of the TX-RX-scanner module is hermetically sealed.

In step S604, a PCB board corresponding to the integrated TX-RX-scanner module is generated, where the PCB board includes one or more serving electronic components connectable to the optical components included in the TX-RX-scanner module through the pins located on the edges of the integrated TX-RX-scanner module. The generated PCB board may include various serving electronic components, such as power supplies for each optical component, FPGA for data acquisition and analysis, readout circuit, and FPGA for controlling the optical components. The generated PCB may be in the form of a single piece where the various serving electronic components may be integrated into a single piece. Alternatively, the generated PCB may be in the form of multiple pieces, where different pieces of PCB boards may include respective serving electronic components. In some embodiments, the generated PCB(s) may also include certain I/O ports, such as pins, for establishing communication with the respective optical components in the integrated TX-RX-scanner module.

In step S606, the one or more serving electronic components inside the generated PCB(s) are connected with the optical components in the integrated TX-RX-scanner module through the plurality of pins disposed on the edges of the integrated TX-RX-scanner module, to form a LiDAR system containing an integrated TX-RX-scanner module. The as-formed LiDAR system may have a much smaller size than other existing LiDAR systems, which may greatly reduce the overall LiDAR module cost, ease overall integration in the formation of a LiDAR system, and add module compatibility on a vehicle, thereby facilitating the use of a LiDAR system in practical applications. One of such applications is described below inFIG.7.

FIG.7is a flow chart of an exemplary optical sensing method700performed by a LiDAR system containing an integrated TX-RX-scanner module, according to embodiments of the present disclosure. In some embodiments, method700may be performed by various components of a disclosed LiDAR system102, e.g., by various components included in an integrated TX-RX-scanner module and a coupled PCB board. In some embodiments, method700may include steps S702-S706. It is to be appreciated that some of the steps may be optional. Further, some of the steps may be performed simultaneously, or in a different order than that shown inFIG.7.

In step S702, a laser emitter of an optical sensing system (e.g., laser strip402of integrated TX-RX-scanner module401of LiDAR system102) may emit an optical signal toward one or more optics (e.g., fast axis collimator lens406and slow axis collimator lens408) of the optical sensing system. As previously described, the one or more optics (e.g.,406and408) and the laser strip402may be disposed on a same substrate inside a hermetically sealed package405of integrated TX-RX-scanner module401. The one or more optics (e.g.,406and408) may be aligned with laser strip402before being hermetically sealed in the package. The laser strip402may be connected to a power supply located outside (e.g., on a PCB) the integrated TX-RX-scanner module401. The power supply may provide the power to laser strip402when emitting an optical signal. In some embodiments, the one or more optics (e.g.,406and408) may form the optical signal received from the laser strip into a predefined shape (e.g., a narrow laser beam).

In step S704, a scanner of the optical sensing system may direct the optical signal having the predefined shape to an environment surrounding the optical sensing system. The shaped optical signal may be directed to the environment outside the package of integrated TX-RX-scanner module401, e.g., through a glass window on the sidewall of the package. The environment may include one or more objects, which may reflect the optical signal back to integrated TX-RX-scanner module401of LiDAR system102.

As previously described, the scanner of the optical sensing system may include two separate parts to implement different functions. For instance, the scanner may include a scanning mirror or reflector that reflects the shaped optical signal, and a platform (e.g., a MEMS-based platform) that drives the motion of the scanning mirror or reflector. Both the scanning mirror or reflector part and the platform part are packaged inside the integrated TX-RX-scanner module. On the other hand, the controller(s) for providing the instructions to the platform (e.g., in the form of FPGA) and the power electronics for powering the motion of the platform may be excluded from the integrated TX-RX-scanner module, but are included inside a PCB outside the TX-RX-scanner module. The controller may send the instructions from the FPGA inside the PCB to the driving platform through the pins on the edges of the integrated TX-RX-scanner module, which then drive the scanning mirror or reflector to direct the shaped optical signal towards the environment according to a predefined pattern.

In step S706, a receiver of the optical sensing system, which includes a photodetector (e.g., a photosensor or a photosensor array422) may receive the returned optical signal from the environment. For instance, after passing through the glass window (e.g., glass window416) of the sealed package of integrated TX-RX-scanner module401, the returned optical signal may be reflected by one or more reflectors (e.g., beam splitter410) that guide the returned optical signal to the photosensor array422of the receiver frontend. Next, the returned optical signal may pass through a receiving lens (e.g., receiving lens418), which converges and focuses the returned optical signal on the photosensor(s) of the receiver frontend. The photosensor(s) then senses the returned optical signal and converts the optical signal to an electrical signal reflecting the intensity of the optical signal. Depending on the configuration of the receiver frontend, the electrical signal may be a current or voltage signal. Through bonding wires, the electrical signal may be then transmitted to a serving electronic component (e.g., a readout circuit) outside the package of the integrated TX-RX-scanner module for further processing, e.g., converting the electrical signal to a digital signal. The digitalized signal may be forwarded to another serving electronic component (e.g., in the form of FPGA) of the optical sensing system for further processing, e.g., for data acquisition and analysis, and for constructing a high-definition map or 3-D buildings and city modeling during a navigation process by a vehicle mounted with the optical sensing system containing a disclosed TX-RX-scanner module.

Although the disclosure is made using a LiDAR system as an example, the disclosed embodiments may be adapted and implemented to other types of optical sensing systems that use receivers to receive optical signals, not limited to laser beams. For example, the embodiments may be readily adapted for optical imaging systems or radar detection systems that use electromagnetic waves to scan objects.

It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.