A scanning laser radar based on SPAD chip

Abstract

The application provides a scanning laser radar based on a SPAD chip. The transmitter comprises a plurality of VCSEL chips arranged in a staggered manner along a first direction, each VCSEL chip comprising at least one light-emitting unit extending along the first direction; the collector comprises a plurality of SPAD chips arranged in a staggered manner along the first direction, each SPAD chip comprising at least one photosensitive unit extending along the first direction and a readout circuit; the scanning mirror is used for transmitting a laser signal to a target area and moving the position of the laser signal transmitted to the target area along a second direction through movement to realize scanning of the target area; the control and processor is used for acquiring the distance of the target; wherein the transmission field of view corresponding to adjacent VCSEL chips and the collection field of view corresponding to adjacent SPAD chips are spliced along the first direction, and the first direction is perpendicular to the second direction. The application can effectively ensure the continuity of the field of view in the first direction when the laser radar detects the target area.

Description

[0001] The present application relates to the technical field of optical imaging, and in particular to a laser radar and an electronic device.

[0002] The laser radar is an optical detection system, which usually includes a transmitter, a collector and a processor. The working principle is that the transmitter emits a light signal to a target object, the light signal is reflected by the target object to form a return signal and is incident on the collector. After the collector receives the return signal, the processor combines the light signal and the return signal and performs some appropriate signal processing, so as to obtain the characteristic information of the target object, such as distance, direction, height, speed, attitude and shape, etc. As the most widely used application, the laser radar can be combined with the TOF (Time of Flight) technology to calculate the time difference or phase difference between the light signal emitted by the transmitter and the return signal received by the collector, so as to convert the distance between the target object and itself, and finally obtain point cloud data containing the distance value of the target object.

[0003] In related technologies, the laser radar based on the TOF technology mainly includes two categories of scanning type and full solid state. The scanning type laser radar can be divided into mechanical type and non-mechanical type according to different scanning methods. The mechanical type realizes 360° large field of view optical detection by rotating the base (the transmitter, the collector and the processor are arranged on the base). The non-mechanical type realizes scanning by setting a rotating mirror, a vibrating mirror, a reflecting mirror and the like to deflect the light path of the emitted light signal. In the scanning type laser radar system, the collector is usually a photosensitive element such as APD or SiPM. The collector can also use a photon detector based on single photon avalanche diode (SPAD) to realize. The SPAD is a detector that can capture single photons of tens of picoseconds in very high time resolution, and can be manufactured in a special semiconductor process or in a standard CMOS process to form a SPAD chip. The SPAD chip integrates a SPAD array and a corresponding circuit area. When the collector selects the SPAD chip, the conventional arrangement method is no longer applicable.

[0004] Therefore, it is necessary to improve the structure of the above laser radar.

[0005] The present application provides a scanning type laser radar, which aims to solve some of the problems mentioned in the background in related technologies.

[0006] ​​​To solve the above technical problems, the first aspect of the embodiment of the present application provides a scanning laser radar, comprising: a transmitter configured to emit a laser signal towards a target area, the transmitter comprising a plurality of VCSEL chips arranged staggeredly along a first direction, each of the VCSEL chips comprising at least one light emitting unit extending along the first direction; a collector configured to collect a return signal reflected by the target and generate an electrical signal, the collector comprising a plurality of SPAD chips arranged staggeredly along the first direction, each of the SPAD chips comprising at least one light sensing unit extending along the first direction and a readout circuit; a scanning mirror configured to transmit the laser signal to the target area and move the position of the laser signal transmitted to the target area along a second direction to achieve scanning of the target area; and a control and processor configured to obtain the distance of the target according to the electrical signal; wherein the emission field of view corresponding to adjacent VCSEL chips and the collection field of view corresponding to adjacent SPAD chips are spliced along the first direction, and the first direction is perpendicular to the second direction.

[0007] In some embodiments, the positions of the light sensing units in the two adjacent SPAD chips in the collector are different and symmetrically arranged along the first direction.

[0008] In some embodiments, the VCSEL chip comprises a plurality of light emitting units, each of the light emitting units comprises a plurality of light emitting elements arranged in sequence, a plurality of the light emitting units are arranged in sequence along the second direction, and a plurality of the light emitting units are arranged staggeredly along the first direction; the SPAD chip comprises a plurality of light sensing units, each of the light sensing units comprises a plurality of light sensing elements arranged in sequence, a plurality of the light sensing units are arranged in sequence and side by side along the second direction; wherein the light emitting units and the light sensing units correspond one by one. The light sensing unit comprises a plurality of light sensing element arrays, the light sensing element array and the light emitting element form a corresponding detection channel; wherein each light sensing element in the light sensing element array is connected to one readout circuit, and the light sensing elements in the plurality of light sensing element arrays share the readout circuit. In addition, the transmitter further comprises a plurality of drivers, each driver is electrically connected to each transmitting chip, and the driver is configured to drive at least one light emitting element in each transmitting chip to emit light. In one embodiment, the light emitting unit further comprises a plurality of microlens arrays corresponding to the plurality of light emitting units respectively, the number of microlenses in the microlens array is the same as the number of light emitting elements in the corresponding light emitting unit, and the microlens is configured to collimate the light signal emitted by the corresponding light emitting element.

[0009] In some embodiments, the scanning mirror comprises a driving element and a body, the driving element is arranged in the body and drives the body to rotate around a rotation axis, at least one reflecting mirror surface is arranged on the body, the reflecting mirror surface is used for deflecting the optical path of the laser signal emitted by the emitter and deflecting the optical path of the reflected echo signal. At least two reflecting mirror surfaces are arranged on the body, the included angle between the two reflecting mirror surfaces and the rotation axis is the same, or the difference between the included angles of the two reflecting mirror surfaces and the rotation axis is less than or equal to a preset threshold.

[0010] From the above description, compared with the related art, the beneficial effects of the present application are that the emitter comprises a plurality of VCSEL chips arranged in a staggered manner along a first direction for emitting laser signals; the collector comprises a plurality of SPAD chips arranged in a staggered manner along the first direction, each SPAD chip comprising at least one light sensing unit and a readout circuit; the scanning mirror is used for transmitting the laser signal to the target area and moving the position of the laser signal transmitted to the target area along a second direction by movement to realize scanning of the target area; wherein the emission field of view corresponding to adjacent VCSEL chips and the collection field of view corresponding to adjacent SPAD chips are spliced along the first direction, and the first direction is perpendicular to the second direction. When the VCSEL chip and the SPAD chip both comprise a plurality of, the plurality of emission chips and the plurality of collection chips are arranged in a staggered manner along the vertical first direction, and the plurality of emission chips and the plurality of collection chips are one-to-one corresponding, that is, the echo signal reflected by the light signal emitted by each emission chip through the target area is received by the corresponding collection chip. The staggered arrangement form can effectively ensure the continuity of the field of view in the first direction when the laser radar detects the target area. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the related art or the embodiments of the present application, the drawings required to be used in the description of the related art or the embodiments of the present application will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and not all embodiments. Those skilled in the art can obtain other drawings according to these drawings without creating any creative labor.

[0012] Figure 1 A schematic diagram of the system principle of the laser radar;

[0013] Figure 2 A schematic diagram of the structure of the emitter provided by the embodiments of the present application;

[0014] Figure 3 A schematic diagram of the structure of the collector provided by the embodiments of the present application;

[0015] Figure 4 An example diagram of the light sensing unit provided by the embodiments of the present application;

[0016] Figure 5 A schematic diagram of the structure of a lidar provided in an embodiment of this application;

[0017] Figure 6 This is another schematic diagram of the structure of the lidar provided in the embodiments of this application.

Detailed Implementation Methods

[0018] To make the objectives, technical solutions, and advantages of this application more apparent and understandable, this application will be clearly and completely described below with reference to the embodiments and corresponding drawings. Throughout, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions. It is understood that the various embodiments of this application described below are merely illustrative of this application and are not intended to limit this application. That is, all other embodiments obtained by those skilled in the art based on the various embodiments of this application without creative effort are within the scope of protection of this application. Furthermore, the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0019] Figure 1 This is a schematic diagram of the system principle of a lidar. The lidar 10 typically includes a transmitter 11, a collector 12, and a control and processor 13 connected to the transmitter 11 and the collector 12. The transmitter 11 continuously emits pulse beams 30 with fixed time intervals (pulse periods) to each target point in the target object 20, and at least part of the pulse beams 30 are reflected by the target points to form reflected beams 40 that are incident on the collector 12. The collector 12 collects the photons in the reflected beams 40 reflected by the target points and outputs the corresponding photon signals. The control and processor 13 synchronizes the trigger signals of the transmitter 11 and the collector 12 to calculate the flight time of the photons in the beam from emission to reception.

[0020] Specifically, the emitter 11 generally comprises one or more light sources 111, an emission optical element 112, and a driver 113, etc., and each light source 111 is configured to continuously emit a pulsed light beam 30 with a fixed time interval (pulse period) to each target point in the target object 20. In practical applications, the light source 111 can be a VCSEL array light source chip formed by generating multiple VCSEL (Vertical-Cavity Surface-Emitting Laser) light sources on a single semiconductor substrate, and it can emit a pulsed light beam 30 to the target object 20 at a certain frequency (pulse period) under the control of the driver 113, and the pulsed light beam 30 is projected on the target point on the target object 20 through the emission optical element 112 to form a corresponding illumination spot, wherein the frequency needs to be set according to the measurement distance. In some examples, the emission optical element 112 can be in the form of a combination of one or more of a lens (a lens group composed of multiple single lenses), a diffractive optical element (DOE), a diffuser, a metasurface optical element, a microlens array (MLA), a Powell prism, a mask plate, a mirror, a MEMS (Micro-Electro-Mechanical System) mirror, etc.

[0021] Specifically, the collector 12 generally comprises a filtering unit 122, a receiving optical element 123, and a pixel array 121 consisting of a plurality of pixels, etc. In actual applications, the receiving optical element 123 images the reflected light beam 40 reflected by the target point on the target object 20 onto the pixel array 121, and at least one pixel in the pixel array 121 collects photons in the reflected light beam 40 reflected by the target point and outputs a corresponding photon signal (the case where a pixel in the pixel array 121 collects a photon is regarded as a photon detection event, and a corresponding photon signal is output at this time). Exemplarily, the pixels in the pixel array 121 can be at least one of single-photon devices such as SPAD (Single Photon Avalanche Diode, SPAD), SiPM (Silicon photomultiplier, SiPM), etc. that collect photons, and preferably, the pixel array 121 consists of a plurality of SPADs. The SPADs can respond to an incident single photon and output a signal indicating the corresponding arrival time of the received photon at each SPAD. In addition, the collector 12 generally also comprises a readout circuit (not shown in the figure) connected to the pixel array 121. The readout circuit is adapted to the pixels in the pixel array 121 to receive the corresponding photon signals generated by the pixels in collecting photons in the reflected light beam 40, and further output a signal indicating the corresponding flight time of the pulsed light beam 30 to and fro the target point on the target object 20.

[0022] The readout circuit comprises a time-to-digital conversion (TDC) circuit for recording the flight time of a photon from emission to collection and generating a time signal (e.g. a time code). In some embodiments, the readout circuit further comprises a histogram circuit. The time signal is input into the histogram circuit to find a corresponding storage unit (time bin) in the histogram circuit, and the photon count value in this time bin is incremented by 1. After repeatedly emitting the pulsed light beam 30 (pulse sequence) to the target point on the target object 20 multiple times, the time signals of multiple detections are input into the corresponding time bins of the histogram circuit and stored to make the histogram circuit generate a histogram containing the corresponding flight time of the pulse.

[0023] The control and processing processor 13 receives and processes the histogram output by the collector 12. Generally, a filtering process is first performed to reduce the influence of noise, and then the filtered histogram is subjected to echo extraction and calculation of the centroid position of the echo. Finally, the flight time of the pulse to and fro the target point is determined according to the time corresponding to the centroid position (the time corresponding to the centroid position is the flight time of the pulse to and fro the target point).

[0024] In some embodiments, when the laser radar system is a scanning laser radar, it usually further comprises a scanning mirror for changing the position of the laser signal transmission to the target area and moving along one direction to realize scanning of the target area. In such a laser radar system, the transmission light path of the emitted light signal overlaps with the transmission light path of the received signal, which is usually referred to as a public system, Figure 5 and Figure 6 The coaxial laser radar system proposed in the present application is shown. In practical applications, after the laser radar starts to work, the emitter 11 is configured to emit a linear light beam in the direction of the target area, and the linear light beam extends along a first direction, such as a vertical direction. The vertical field of view angle of the linear light beam corresponds to the vertical field of view angle of the detection field of view of the laser radar. The scanning unit changes the position of the linear light beam projected to the target area, so that the linear light beam constantly shifts along a second direction, i.e., a direction perpendicular to the first direction, thereby completing the detection of the two-dimensional target area. For ease of description, the embodiments of the present application will be described below with the first direction as the vertical direction as an example, and the second direction as the horizontal direction.

[0025] Figure 2 and Figure 3 The structure schematic diagram of the emitter and the collector proposed in the present application is shown. The emitter 21 comprises an emitter circuit board 211 and a plurality of emitter chips 212 arranged on the emitter circuit board 211, each emitter chip comprising at least one light emitting unit 213 extending along a first direction 101, the light emitting unit 213 comprising a plurality of light emitting elements 2131 arranged in sequence, and the plurality of emitter chips are arranged in a staggered manner along the first direction 101 so that the corresponding emission fields of view of adjacent emitter chips are spliced along the first direction, and each emitter chip 212 is used for emitting a light signal to a target area. The collector 31 comprises a collector circuit board 311 and a plurality of collector chips 312 arranged on the collector circuit board 311, each collector chip comprising at least one light sensing unit extending along the first direction 101 and a readout circuit, and the plurality of collector chips are arranged in a staggered manner along the first direction 101 so that the corresponding collection fields of view of adjacent collector chips are spliced along the first direction, and each collector chip 312 is used for receiving a reflected echo signal from the target area, and the plurality of collector chips 312 correspond one-to-one to the plurality of emitter chips 212.

[0026] Among them, the emitter chip 212 is a VCSEL chip, the emitter chip 212 comprises at least one light emitting unit 213, and the light emitting unit 213 comprises a plurality of light emitting elements 2131 arranged in sequence. The collector chip is a SPAD chip, comprising a light sensing region 314 and a circuit region 313, the light sensing region 314 is formed by at least one light sensing unit 315, the light sensing unit 315 comprises a plurality of light sensing elements arranged in sequence, and is used for detecting a reflected echo signal, and the readout circuit connected to each light sensing element forms the circuit region 313.

[0027] In the embodiments of this application, SPAD chips can be manufactured from silicon wafers using known CMOS manufacturing processes to form a stacked structure. However, since the size of the circuit region 314 is larger than that of the photosensitive region 313, if the acquisition chips 312 are arranged sequentially on the circuit board along the vertical direction (first direction), the receiving field of view of two adjacent acquisition chips will be discontinuous in the first direction, i.e., the detection field of view of the lidar will be discontinuous. Therefore, this application proposes an optimized arrangement, in which multiple SPAD chips are staggered in the vertical direction, so that the photosensitive regions in adjacent acquisition chips are continuous in the vertical direction, i.e., the photosensitive regions in adjacent acquisition chips are spliced ​​together in the vertical direction without overlapping. Correspondingly, multiple emitting chips 312 are also configured to be staggered in the vertical direction, and the emitting regions corresponding to the emitting units in the multiple emitting chips are also spliced ​​together in the vertical direction without overlapping. Multiple transmitting chips 212 correspond to multiple acquiring chips 312, which means that the echo signal of the light signal emitted by each transmitting chip 212 after being reflected by the target area is received by the corresponding acquiring chip 312. The purpose of setting multiple transmitting chips 212 and multiple acquiring chips 312 to be staggered in the vertical direction is to ensure the continuity of the field of view in the vertical direction when the lidar detects the target area.

[0028] It is understood that the splicing without overlap mentioned in this application refers to an idealized situation that covers the entire field of view and minimizes signal interference, but it is not the only limitation. For example, deviations during the manufacturing process, the influence of temperature during product use, or slight overlap or separation should all be included within the scope of this application.

[0029] In one embodiment, among the multiple acquisition chips 312 arranged on the collector 31, the photosensitive areas 314 within two adjacent acquisition chips are positioned differently on the acquisition chip, and are configured symmetrically along the vertical direction. Because the acquisition chips have a relatively large size due to the presence of circuitry, while the emitting chips have a compact structure and a small size, and the light-emitting units within the emitting chips are only positioned corresponding to the photosensitive areas, this arrangement allows for a compact arrangement of the emitting chips, reducing the overall size of the transmitter.

[0030] like Figure 2 As shown, the emitting chip 212 includes multiple light-emitting units 213, each light-emitting unit 213 including multiple light-emitting elements 2131 arranged sequentially along the vertical direction for emitting laser signals toward the target area. The multiple light-emitting units 213 are arranged sequentially along the horizontal direction, and any two adjacent light-emitting units 213 are staggered, so that the emission fields of the light-emitting elements in the multiple light-emitting units intersect each other along the vertical direction to uniformly cover the detection field of view. In one embodiment, the arrangement of multiple light-emitting units in any two adjacent emitting chips in the transmitter 21 is symmetrical along the vertical direction. For example... Figure 2In the illustrated embodiment, a single emitting chip 212 includes four staggered light-emitting units 213, each light-emitting unit 213 including four light-emitting elements 2131, the first light-emitting element in the four light-emitting units being staggered sequentially, and the staggered distance being determined according to the size of the light-emitting element.

[0031] When the emitting chip 212 contains multiple staggered light-emitting units 213 (each light-emitting unit 213 includes multiple light-emitting elements 2131), the vertical field of view between any two adjacent light-emitting elements 2131 in any two adjacent light-emitting units 213 is less than or equal to half the vertical field of view between any two adjacent light-emitting elements 2131 in the same column. In practical applications, each light-emitting element 2131 includes a cavity and an active region located in the middle of the cavity (i.e., Figure 2 The area of ​​the active region is smaller than the cavity surface area (the solid black dots in the diagram). The emitted light signal is emitted through the active region. The light-emitting elements 2131 of a single light-emitting unit 213 are arranged sequentially in the vertical direction. In order to effectively increase the number of scan lines when adding multiple light-emitting units, it is necessary that the light signals emitted by each light-emitting element do not overlap when projected onto the target area. Assuming that the size between the active regions of any two adjacent light-emitting elements in a single light-emitting unit is m (the distance between the centers of two circles is shown in the diagram), and the size of the active region of a single light-emitting element is n (the radius of the circle is shown in the diagram), then m / n light-emitting units can be staggered on a single emitting circuit board 211. If each light-emitting element in a single light-emitting unit is spaced a certain distance apart, the number of light-emitting units that can be set on a single emitting chip can also be increased. Specifically, it can be set according to the distance between adjacent active regions. When there are multiple light-emitting units, they are arranged sequentially in the horizontal direction and staggered in sequence. This is equivalent to inserting multiple light-emitting elements between any two adjacent light-emitting elements of the first light-emitting unit. This design results in a larger number of light-emitting elements in a single emitting chip and a more uniform distribution. In this case, the light spots emitted by all the light-emitting elements are spliced ​​together on the target area to form dense scan lines, thereby improving detection accuracy and resolution.

[0032] Although the number of light-emitting units in a single emitting chip directly determines the size of the lidar and its vertical field of view, by staggering multiple light-emitting units, the number of linear beams projected by the lidar can be increased without increasing the overall size, thus improving the vertical resolution. For example... Figure 2 In the illustrated embodiment, the lidar can be configured with 64 lines. The number of lines of the lidar can be further increased by increasing the number of emitting chips or the number of light-emitting elements in the emitting chips.

[0033] likeFigure 3 As shown, the collection chip 312 includes a plurality of light sensing units 315 for receiving the laser signal reflected by the target and generating an electrical signal, and the readout circuit in the circuit area 313 is connected with the light sensing unit for receiving the electrical signal and recording the time of flight of the optical signal from emission to reception. Among them, the light sensing unit is correspondingly arranged with the light emitting unit and the number is the same. As shown in the embodiment, the collection chip 312 includes four light sensing units 315, and each light sensing unit includes a plurality of light sensing elements. The plurality of light sensing units 315 are also arranged in sequence along the horizontal direction, but any two adjacent light sensing units 315 do not need to be staggered in the vertical direction, but can be arranged side by side. In this case, the echo signal of the light signal emitted by each light emitting unit 213 after being reflected by the target area is received by the corresponding light sensing unit 315. Figure 3 As shown, the collection chip 312 includes a plurality of light sensing units 315 for receiving the laser signal reflected by the target and generating an electrical signal, and the readout circuit in the circuit area 313 is connected with the light sensing unit for receiving the electrical signal and recording the time of flight of the optical signal from emission to reception. Among them, the light sensing unit is correspondingly arranged with the light emitting unit and the number is the same. As shown in the embodiment, the collection chip 312 includes four light sensing units 315, and each light sensing unit includes a plurality of light sensing elements. The plurality of light sensing units 315 are also arranged in sequence along the horizontal direction, but any two adjacent light sensing units 315 do not need to be staggered in the vertical direction, but can be arranged side by side. In this case, the echo signal of the light signal emitted by each light emitting unit 213 after being reflected by the target area is received by the corresponding light sensing unit 315.

[0034] It should be noted that from the above description, it can be known that there is a corresponding relationship between the light emitting element and the light sensing element (that is, the echo signal of the light signal emitted by the light emitting element after being reflected by the target area is received by the corresponding light sensing element). Generally, the position of the signal emitted by each light emitting element and reflected to the light sensing unit domain needs to be calibrated, that is, the light spot calibration. In the measurement process, the light sensing element at the corresponding position can be correspondingly turned on to detect the light signal when the light emitting element is turned on. However, in actual application, the SPAD size is small and the reflected light spot is large, and the imaging position of the reflected light spot on the light sensing unit is not fixed due to the influence of system tolerance, parallax and some other factors, and there is usually a certain offset. Therefore, in the present application, each light emitting element is correspondingly arranged with each light sensing element array to solve the influence of the offset on the detection accuracy.

[0035] As shown, the light sensing unit 411 includes a plurality of light sensing element arrays, each light sensing element array is correspondingly arranged with each light emitting element to form a detection channel, each light sensing element array includes a plurality of light sensing elements, and each light sensing element is connected with a readout circuit. Therefore, the light sensing unit is correspondingly connected with an array of readout circuits. Figure 4 As shown, the light sensing unit 411 includes a plurality of light sensing element arrays, each light sensing element array is correspondingly arranged with each light emitting element to form a detection channel, each light sensing element array includes a plurality of light sensing elements, and each light sensing element is connected with a readout circuit. Therefore, the light sensing unit is correspondingly connected with an array of readout circuits. Figure 4 As shown in an embodiment, for example, the light sensing unit 411 includes four light sensing element arrays, each light sensing element array includes 5*5 light sensing elements, and each light sensing element is connected with a readout circuit 421. Therefore, the light sensing element array is correspondingly connected with a 5*5 readout circuit array. Each light sensing element can be one SPAD, or a plurality of SPADs, such as a macro-pixel composed of 3*3 SPADs. The plurality of light sensing elements in the light sensing unit share the readout circuit array, that is, the light sensing elements in the plurality of light sensing element arrays share one readout circuit, Figure 4The same reference numerals schematically indicate photosensitive elements that share the same readout circuit. For example, photosensitive element number 5 in each photosensitive element array shares a readout circuit 421. The configuration of shared readout circuits can reduce chip size while ensuring detection accuracy, further reducing the overall size of the data acquisition unit.

[0036] In some embodiments, the transmitter 21 further includes multiple drivers (not shown), each driver being electrically connected to each transmitter chip 212, for independently controlling the light emission of each transmitter chip, and for controlling the light emission of individual light-emitting elements within each transmitter chip. During the detection process, each driver drives at least one light-emitting element to emit light, while simultaneously activating the photosensitive element array in the corresponding photosensitive area to collect echo signals. The driver can control each light-emitting element in each light-emitting unit to be turned on sequentially according to a predetermined turn-on sequence, for example, first controlling the first light-emitting element 2131 in each light-emitting unit 213 to be turned on and controlling the first photosensitive element array 3231 in each photosensitive unit 323 to be turned on, then controlling the second light-emitting element 2131 in each light-emitting unit 213 to be turned on and controlling the second photosensitive element 3231 in each photosensitive unit 323 to be turned on, and so on until the detection of the target area is completed. In some embodiments, in order to reduce the heat dissipation of the transmitter and improve power consumption, only one light-emitting element in each transmitter chip can be controlled to emit light at a time. This light-emitting element can be any light-emitting element in any light-emitting unit, in which case the detection beam is 4 lines during a single detection. In some embodiments, in order to improve the detection frame rate, each light-emitting unit in the transmitting chip can be controlled to emit light at one time, so the transmitting line bundle can be 16 lines in a single detection.

[0037] In some embodiments, the light-emitting unit 213 further includes a plurality of microlenses corresponding to the plurality of light-emitting elements 2131 respectively. Figure 2 (Not shown in the image), the function of the microlens is to collimate the light signal emitted by the corresponding light-emitting element 2131 and project it onto the scanning mirror 40. It is understood that when the light-emitting element 2131 is replaced by a light-emitting array, the microlens should also be replaced by a microlens array comprising multiple microlenses, and the number of microlenses in the microlens array is the same as the number of light-emitting elements 2131 in the corresponding light-emitting array. In this case, the light signal emitted by the light-emitting element 2131 in the light-emitting array will be collimated by the corresponding microlenses in the corresponding microlens array and projected onto the scanning mirror 40. For example, the light-emitting array adopts a back-emitting form; in this case, the microlens array can be provided on the back-emitting side of the light-emitting array.

[0038] Figure 5A structural schematic diagram of a scanning laser radar provided by an embodiment of the present application, the laser radar system 50 provided by the embodiment of the present application includes a transmitter 51, a collector 52, a reflector 53 and a scanning mirror 54. The transmitter 51 and the collector 52 are arranged as described in the foregoing embodiments, which will not be repeated here. The laser radar system further includes a transmitting optical element 65 and a receiving optical element 66, which are arranged on the transmission paths of the transmitting optical signal and the echo signal respectively. The reflector 53 is used to reflect the optical signal transmitted by the transmitter 51 and make it incident on the scanning mirror 54. The scanning mirror 54 changes the transmission direction of the optical signal by movement so as to make it transmitted to the target area and scan the target area. The echo reflected by the target is transmitted to the scanning mirror 54 along the same optical path and is incident on the collector after reflection along the edge of the reflector 53. In some embodiments, the scanning mirror 54 includes a rotating mirror, a vibrating mirror or a MEMS mirror, etc. For the embodiment, the optical axis of the outgoing optical signal and the optical axis of the echo signal are no longer independent of each other, and partially coincide along the reflector and the scanning mirror. We call this a coaxial scheme. In some embodiments, the reflector 53 can also be a semi-transmissive and semi-reflective mirror, part of which is a reflective area for reflecting the optical signal to emit the laser signal, and part of which is a transmissive area for transmitting the echo signal to be incident on the collector. In the embodiment of the present application, the reflector is used to lengthen the optical path of the transmitting optical signal and increase the distance between the transmitter and the collector, so as to reduce the influence of heat dissipation on detection. In some embodiments, the reflector can also not be configured.

[0039] In one embodiment, the scanning mirror 54 comprises a driving element (not shown in the figure) and a body having at least one mirror surface, wherein the driving element is arranged in the body and is used to drive the body to rotate around the rotation axis in the three-dimensional space, so as to deflect the light path of the light signal emitted by the emitter 51 and the echo signal reflected by the target area through the reflection of the at least one mirror surface. When the laser radar system 50 starts to detect, the scanning mirror 54 is in an initial position, and the linear light signal reaching the target area will generate a corresponding echo signal after being reflected by the target area. The echo signal first reaches the scanning mirror, and the scanning mirror 54 deflects the light path of the echo signal and then projects it to the collector 52, so that the collector 52 can calculate the time of flight according to the echo signal, thereby completing the detection of a sub-region in the target area. After the next measurement is started, the emitter 51 emits the same linear light beam to the target area, and the driving element drives the body to rotate to deflect the exit angle of the linear light beam by a certain angle to change the exit direction of the light beam, so that the linear light beam irradiates a next sub-region in the target area by a certain distance along a second direction, and the echo reflected by the sub-region enters the mirror surface along the same light path. The second direction is perpendicular to the first direction, such as the horizontal direction. After continuous deflection for multiple times, the detection of the target area is completed. Thus, the horizontal field of view angle of the detection field of view of the laser radar is related to the horizontal field of view angle of the linear light beam and the number of deflections of the scanning mirror. Correspondingly, if the first direction is the horizontal direction, the second direction is the vertical direction. In the embodiment of the present application, the driving element can be a commonly used element with a rotating driving function in the art, such as a brushless motor, which can include a stator, a rotor, a rotating shaft, a winding, and the like. Details are not described here.

[0040] In one embodiment, the body of the scanning mirror 54 is provided with at least two mirror surfaces, and the angles between the multiple mirror surfaces and the rotation axis are the same, or the difference between the angles between the multiple mirror surfaces and the rotation axis is less than or equal to a preset threshold, such as 1 degree. Each mirror surface is used to deflect the light path of the light signal emitted by the emitter to project to the target area, and to deflect the light path of the echo signal reflected by the target area to project to the collector. Although the multiple mirror surfaces can deflect the light path of the light signal and the echo signal, the present embodiment still provides multiple mirror surfaces instead of only one mirror surface as in the last embodiment, in order to increase the utilization rate of the rotation angle.

[0041] In some embodiments, the laser radar further comprises a housing having a receiving cavity and an opening communicating between the receiving cavity and an external space. The emitter and the collector are both arranged in the receiving cavity and are located away from the opening. The scanning mirror is arranged in the receiving cavity and is located close to the opening.

[0042] Figure 6 Another structure schematic diagram of the scanning laser radar provided by the embodiment of the present application is provided. The laser radar system 60 provided by the embodiment of the present application comprises a first emitter 61, a second emitter 67, a collector 62, a first mirror 68, a second mirror 63, a scanning mirror 64, a transmitting optical element 65 and a receiving optical element 66. Compared with the prior art, the embodiment of the present application has the advantages of Figure 5 In the embodiment shown, the second emitter 67 and the first mirror 68 are added in the embodiment of the present application. The first pulse signal emitted by the first emitter 61 is reflected by the first mirror 68 and then is incident to the second mirror 63, the second mirror 63 reflects the first pulse signal to the scanning mirror 64, and the first pulse signal is transmitted to the target area via the scanning mirror 64. The second emitter 67 and the first emitter 61 are respectively located on two sides of the first mirror 68, and the first mirror 68 is provided with a hole at the edge thereof so that the second pulse signal emitted by the second emitter 67 can pass through the first mirror 68 and be incident to the second mirror 63, and the second pulse signal is reflected by the second mirror 63 and transmitted to the target field via the scanning mirror 64. Preferably, the number of light emitting elements in the second emitter 67 is less than the number of light emitting elements in the first emitter 61.

[0043] In the detection process, the light signal emitted by the first emitter 61 is used to detect the target point at a far distance, and the light signal emitted by the second emitter 67 is used to detect the target point at a near distance. Specifically, the control and processing unit is configured to control the first emitter 61 to continuously emit k first pulses in a frame period, and then control the second emitter 67 to emit one second pulse, so as to continuously and alternately complete the collection of one frame of data on this basis, k is a positive integer greater than or equal to 2. The first pulse is used to detect the target at a far distance, and the second pulse is used to detect the target at a near distance, and the pulse parameters of the first pulse can be configured to be greater than the pulse parameters of the second pulse, the pulse parameters including peak optical power, pulse width and pulse interval.

[0044] It should be noted that the above-mentioned embodiments are only preferred implementations of the embodiment of the present application, and are not the only limitation on the specific structure of the emitter, the collector and the scanning unit. Therefore, those skilled in the art can flexibly set the actual application scene on the basis of the embodiment of the present application.

[0045] Finally, the electronic device provided by the embodiment of the present application comprises the laser radar described above, which can obtain the time experienced between the echo signal received by the collector and the light signal emitted by the emitter, and thus obtain the depth value information of the target region, and finally generate the depth image of the target region according to the obtained depth value information. It can be understood that when the electronic device needs to have the function of depth imaging, it can be provided with the aforementioned laser radar provided by the embodiment of the present application; for example, for the electronic device such as a sweeping robot, a meal / delivery robot, etc., which needs to have the function of depth imaging, in this case, it needs to be provided with the aforementioned laser radar provided by the embodiment of the present application, and the purpose is to pre-knowledge the surrounding environment, that is, the laser radar will detect the surrounding environment in real time to determine whether there is an obstacle, so as to plan the next action and path.

[0046] It should be noted that each embodiment in the present application is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between each embodiment can be referred to each other.

[0047] It should also be noted that in the present application, the terms "comprise", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "comprises a" does not exclude the presence of another identical element in the process, method, article or device comprising the element.

[0048] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined in the present application can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown in the present application, but will conform to the widest scope consistent with the principles and novel features disclosed in the present application.

Claims

1. A scanning lidar based on a SPAD chip, characterized in that, include: A transmitter for emitting laser signals toward a target area, the transmitter comprising a plurality of VCSEL chips staggered along a first direction, each VCSEL chip comprising at least a plurality of light-emitting units extending along the first direction; each light-emitting unit comprising a plurality of light-emitting elements arranged in sequence, the plurality of light-emitting units being arranged in sequence along a second direction, and the plurality of light-emitting units being staggered along the first direction; A data acquisition unit is used to acquire echo signals reflected by a target and generate electrical signals. The data acquisition unit includes multiple SPAD chips staggered along a first direction. Each SPAD chip includes at least multiple photosensitive units extending along the first direction and a readout circuit. Each SPAD chip includes multiple photosensitive units arranged sequentially and side-by-side along a second direction. Each light-emitting unit corresponds one-to-one with the photosensitive unit. Each photosensitive unit includes multiple photosensitive element arrays. Each photosensitive element in the photosensitive element array is connected to a readout circuit, and the photosensitive elements in the multiple photosensitive element arrays share the readout circuit. A scanning mirror is used to transmit the laser signal to a target area and to shift the position of the laser signal transmission to the target area along a second direction by movement. A controller and processor for obtaining the distance to the target based on the electrical signal; The emission field of view corresponding to adjacent VCSEL chips and the acquisition field of view corresponding to adjacent SPAD chips are spliced ​​along the first direction, and the first direction is perpendicular to the second direction.

2. The lidar as described in claim 1, characterized in that, The photosensitive units in two adjacent SPAD chips in the collector are arranged symmetrically at the center.

3. The lidar as described in claim 1, characterized in that, The photosensitive element array and the light-emitting element form a corresponding detection channel.

4. The lidar as described in claim 1, characterized in that, The transmitter also includes multiple drivers, each driver being electrically connected to each VCSEL chip, and the drivers are used to drive at least one light-emitting element in each VCSEL chip to emit light.

5. The lidar as described in claim 1, characterized in that, The light-emitting unit further includes multiple microlens arrays corresponding to the multiple light-emitting units. The number of microlenses in the microlens array is the same as the number of light-emitting elements in the corresponding light-emitting unit. The microlenses are used to collimate the light signals emitted by the corresponding light-emitting elements.

6. The lidar as described in claim 1, characterized in that, The scanning mirror includes a driving element and a body. The driving element is disposed in the body and drives the body to rotate around a rotation axis. The body is provided with at least one reflective mirror surface, which is used to deflect the emitted laser signal and the reflected echo signal.

7. The lidar as described in claim 6, characterized in that, The main body is provided with at least two reflective mirrors, the two reflective mirrors are at the same angle to the rotation axis, or the difference between the two reflective mirrors and the rotation axis is less than or equal to a preset threshold.

8. The lidar as described in claim 6, characterized in that, The lidar also includes a second transmitter, a first reflector, and a second reflector; The first pulse signal emitted by the transmitter is reflected by the first and second reflectors and then transmitted to the scanning mirror, which reflects the first pulse signal to the distant target. The second pulse signal emitted by the second transmitter passes through the first reflector and is reflected by the second reflector to the scanning mirror, which then reflects the second pulse signal to the nearby target.

9. The lidar as described in claim 8, characterized in that, The pulse parameter of the first pulse signal is greater than the pulse parameter of the second pulse signal.

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