WO2020077514A1 - 一种激光雷达系统 - Google Patents

一种激光雷达系统 Download PDF

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Publication number
WO2020077514A1
WO2020077514A1 PCT/CN2018/110336 CN2018110336W WO2020077514A1 WO 2020077514 A1 WO2020077514 A1 WO 2020077514A1 CN 2018110336 W CN2018110336 W CN 2018110336W WO 2020077514 A1 WO2020077514 A1 WO 2020077514A1
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WO
WIPO (PCT)
Prior art keywords
light
light source
lidar system
unit
reflected
Prior art date
Application number
PCT/CN2018/110336
Other languages
English (en)
French (fr)
Inventor
石拓
夏冰冰
刘佳尧
Original Assignee
北京一径科技有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by 北京一径科技有限公司 filed Critical 北京一径科技有限公司
Priority to EP18937053.9A priority Critical patent/EP3722832B1/en
Priority to US16/958,719 priority patent/US11675058B2/en
Publication of WO2020077514A1 publication Critical patent/WO2020077514A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/484—Transmitters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/08—Systems determining position data of a target for measuring distance only
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/481—Constructional features, e.g. arrangements of optical elements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/481—Constructional features, e.g. arrangements of optical elements
    • G01S7/4814—Constructional features, e.g. arrangements of optical elements of transmitters alone
    • G01S7/4815—Constructional features, e.g. arrangements of optical elements of transmitters alone using multiple transmitters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/481—Constructional features, e.g. arrangements of optical elements
    • G01S7/4816—Constructional features, e.g. arrangements of optical elements of receivers alone
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/481—Constructional features, e.g. arrangements of optical elements
    • G01S7/4817—Constructional features, e.g. arrangements of optical elements relating to scanning
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/486—Receivers
    • G01S7/4861—Circuits for detection, sampling, integration or read-out
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/486—Receivers
    • G01S7/4861—Circuits for detection, sampling, integration or read-out
    • G01S7/4863—Detector arrays, e.g. charge-transfer gates
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/42—Simultaneous measurement of distance and other co-ordinates

Definitions

  • the present invention relates to a laser radar system, and in particular, to a non-coaxial receiving laser radar system.
  • Lidar measures the position, speed and other information of the target object by emitting a laser beam to the target object and receiving the beam reflected from the target object.
  • Current lidar systems usually use a single photodetector or a one-dimensional photodetector array (a row of photodetectors or a column of laser detectors) to receive the reflected beam.
  • the light receiving surface of the photodetector is often larger than the spot size of the reflected beam.
  • FOV field of view
  • the lidar When the lidar is used in high-speed and long-distance (for example, several hundred meters) scenes (for example, advanced driver assistance system ADAS), the reflected light reaching the photodetector itself has very little power.
  • the interference light is strong, the signal-to-noise ratio (SNR) of the output signal of the photodetector will be greatly deteriorated, which brings difficulties to the use of the lidar system.
  • SNR signal-to-noise ratio
  • the US patent application US2018 / 0128920A1 discloses that the sensing unit of the lidar system can adopt a two-dimensional array of detectors (such as an avalanche diode APD or a single photon avalanche diode SPAD).
  • the array size depends on the desired resolution, signal-to-noise ratio, and desired detection distance.
  • Using a two-dimensional detector array can improve the resolution, signal-to-noise ratio and detection distance to a certain extent, but it still cannot eliminate the influence of the interference light on the signal-to-noise ratio in the environment.
  • the optical sensor of the lidar includes a SPAD array, and each row of SPAD detectors and each row of SPAD detectors in the array share a row selection transistor and a column selection transistor.
  • the transistor can be a MOSFET or BJT.
  • the corresponding rows and columns are selected in the optical sensor array according to the predicted spot size and the reflection angle, thereby reducing the influence of stray light other than the expected reflected light.
  • the US patent application US2018 / 0074175A1 discloses that a spatial light modulator is arranged before the photodetector of the lidar system. Adjust the spatial light modulator to form a small hole that allows or blocks light transmission. The position of the small hole is adjusted according to the direction in which the laser can be turned. Can effectively block other ambient light and improve the signal-to-noise ratio.
  • the technical problem to be solved by the present invention is to provide a non-coaxial receiving lidar system, which can improve the resolution, the signal-to-noise ratio, and significantly eliminate the influence of the interference light in the environment on the signal-to-noise ratio.
  • the present invention provides a lidar system including: a light emitting unit for emitting light to a target object; the light emitting unit includes a light source and a scanning unit, the scanning unit is configured to A controllable deflection angle reflects the light from the light source to scan the target object; a light receiving unit is used to receive the light reflected from the target object and output a detection value; the light receiving unit includes a photoelectric sensor device; A control unit communicatively coupled with the light emitting unit and the light receiving unit, wherein the control unit is configured to control the light emitting unit, process the detection value; and scan the The deflection angle of the unit is controlled; wherein the light path from the light emitting unit to the target object and the light path from the target object to the light receiving unit are non-coaxial.
  • the light emitting unit includes: a first light source for emitting first light; a second light source for emitting second light; and the scanning unit for deflection The angle reflects the first light and the second light incident on it; the first mirror includes opposing first and second surfaces, where the first light is reflected by the first surface of the first mirror to reach the The scanning unit; and a second reflecting mirror for reflecting the second light, wherein the reflected second light passes through the first reflecting mirror through the second surface of the first reflecting mirror and reaches the scanning unit, wherein , The optical path of the first light reflected off the first mirror overlaps the optical path of the second light reflected off the second mirror.
  • the light emitting unit in the first aspect further includes: a third light source for emitting third light; and a third mirror for reflecting the third light
  • the second reflecting mirror includes opposing first and second surfaces, the second light is reflected by the first surface of the second reflecting mirror, and the reflected third light passes through the second in turn
  • the second surface of the reflecting mirror and the second surface of the first reflecting mirror reach the scanning unit after being transmitted, wherein the optical path of the third light reflected from the third reflecting mirror is different from that of the second reflecting mirror
  • the first light source and the second light source are the same light source, and the position of the same light source can be adjusted so that the light emitted at the first position passes through The optical path reflected by the first mirror overlaps the optical path reflected by the second mirror by the light emitted at the second position.
  • the light emitting unit includes: a first light source for emitting first light; a second light source for emitting second light, wherein the first light and the second light The polarization direction is perpendicular; the scanning unit is used to reflect the first light and the second light incident thereon at a deflection angle; and the polarization beam splitting prism is configured to reflect the first light and transmit the second light, The reflected first light and the transmitted second light reach the same position on the scanning unit via overlapping optical paths.
  • the light emitting unit includes: a light source, a scanning unit, and an optical element for reflecting a part of the reflected light from the scanning unit incident thereon and causing another Part of the transmission through; photodetector assembly, including an arrangement of multiple photodetectors, for receiving reflected light from the optical element and outputting photocurrent, wherein the light emitting unit further includes a processing circuit, the processing circuit is coupled In the photodetector assembly, the processing circuit calculates the deflection angle of the scanning unit according to the photocurrent output by each photodetector in the plurality of photodetectors.
  • the control unit is coupled to the processing circuit and the scanning unit, and is configured to adjust the scanning unit based on the calculated deflection angle.
  • the light emitting unit further includes: a focusing lens positioned between the light source and the scanning unit for focusing the light emitted by the light source onto the scanning unit And a collimating lens for collimating the light reflected from the scanning unit.
  • the light emitting unit in the sixth aspect further includes a beam expanding lens for expanding the light collimated by the collimating lens.
  • the light emitting unit in the sixth aspect further includes: a second light source for emitting second light; and a second focusing lens located between the second light source and the scanning unit For focusing the light emitted by the second light source onto the scanning unit; and a second collimating lens for collimating the second light reflected from the scanning unit, wherein the light from the light source and the second light source The light of the light source is respectively focused on the same position of the scanning unit.
  • the first aspect of the light receiving unit includes a photosensor device including: a two-dimensional photodetector array including a plurality of photodetectors; and a two-dimensional readout circuit array including a plurality of readout circuit units; Wherein, the plurality of readout circuit units correspond to the plurality of photodetectors one by one, and each readout circuit unit includes a selection switch.
  • the photosensor device of the light receiving unit further includes a plurality of electrical connectors for coupling the two-dimensional photodetector array and the two-dimensional readout circuit array. Each electrical connector is coupled to each photodetector and the corresponding readout circuit unit in a block or bridge manner.
  • the second aspect of the light receiving unit includes a photosensor device including: a photodetector array including a first number of photodetectors; and a readout circuit including a switch array and a second number of post-processing A circuit, wherein the number of selection switches in the switch array is the product of the first number and the second number, wherein the switch array is used to connect the output of any one of the first number of photodetectors to the second number Processing any one of the circuits.
  • the readout circuit further includes a first number of transimpedance amplifiers corresponding to the first number of photodetectors, and each transimpedance amplifier is used to amplify the signal output from the corresponding photodetector.
  • the third aspect of the light receiving unit includes a photosensor device including: a photodetector array including a plurality of photodetectors; and an optical shutter including a light transmitting portion and a light blocking portion, wherein light passes through The light portion reaches the corresponding photodetector of the photodetector array, wherein the position of the light transmitting portion on the optical shutter is electrically adjustable.
  • the beneficial technical effects of the technical solution of the present invention are: avoiding the disadvantage that the SPAD detector in the optical sensor in the prior art cannot eliminate dark counting, can accurately measure the distance information of the surrounding three-dimensional space environment, and can greatly suppress the background light And the influence of other stray light, to achieve fast and efficient modulation of spatial light.
  • FIG. 1 is a schematic structural diagram of a laser radar system according to an embodiment of the present invention.
  • FIG. 2a is a schematic diagram of the optical path of the first embodiment of the light emitting unit according to the present invention.
  • 2b is a schematic diagram of the optical path of the second embodiment of the light emitting unit according to the present invention.
  • 2c is a schematic diagram of the optical path of the third embodiment of the light emitting unit according to the present invention.
  • FIG. 3a is a schematic diagram of the optical path of the fourth embodiment of the light emitting unit according to the present invention.
  • 3b is a schematic diagram of the frequency of a pulsed light source generated according to the fourth embodiment of the light emitting unit of the present invention.
  • FIG. 4 is a schematic structural view of a fifth embodiment of a light emitting unit according to the present invention.
  • FIG. 5 is a working principle diagram of the sixth embodiment of the light emitting unit according to the present invention.
  • FIG. 6 is a working principle diagram of a seventh embodiment of the light emitting unit according to the present invention.
  • FIG. 7 is a working principle diagram of an eighth embodiment of a light emitting unit according to the present invention.
  • FIG. 8 is a schematic structural view of a photoelectric sensor device according to the first embodiment of the light receiving unit of the present invention.
  • 9a is a schematic diagram of the working principle of the photoelectric sensing device of the light receiving unit of FIG.
  • FIG. 9b is a circuit schematic diagram of the selection switch in FIG. 9a when a field effect transistor FET is used.
  • FIG. 10 is a circuit schematic diagram of a photoelectric sensing device according to a second embodiment of the light receiving unit of the present invention.
  • FIG. 11 is a schematic structural view of a photoelectric sensing device according to a third embodiment of the light receiving unit of the present invention.
  • FIG. 12 is a working principle diagram of one working mode of the optical shutter in FIG. 11.
  • FIG. 13 is a working principle diagram of another working mode of the optical shutter in FIG. 11.
  • the lidar system measures the position, speed and other characteristics of the target object by emitting a laser beam to the target object and detecting the reflected light from the target object.
  • the measuring principle of the lidar system can be divided into: triangulation ranging, pulse ranging based on time of flight (ToF) and phase ranging.
  • FIG. 1 shows a schematic diagram of a lidar system according to an embodiment of the present invention.
  • the lidar system includes a light emitting unit 1, a light receiving unit 2, and a control unit 3.
  • the path of the emitted light from the light emitting unit to the target object is arranged in parallel with the path of the reflected light from the target object to the light receiving unit, and there is no shared part.
  • the light emitting unit 1 is used to emit a laser beam to a target object.
  • the light emitting unit 1 includes a light source 10.
  • the light source 10 may be a laser, such as a solid-state laser, a laser diode, or a high-power laser.
  • the light source 10 may also include LEDs.
  • the light source can emit different forms of light, including pulse, continuous wave (CW) and quasi-continuous wave.
  • the laser may be a vertical cavity surface emitting laser (VCSEL) or an external cavity semiconductor laser (ECDL).
  • the operating wavelength of the light source 10 may be 650 nm to 1150 nm, 800 nm to 1000 nm, 850 nm to 950 nm, or 1300 nm to 1600 nm.
  • the light emitting unit 1 may include an optical component optically coupled with the light source 10 for collimating or focusing the light beam emitted by the light source.
  • the light emitting unit 1 may further include a scanning unit 12 for deflecting the direction of the light beam from the light source 10 to scan the target object to achieve a wider field of view (FOV).
  • the scanning unit 12 may include a MEMS mirror, a prism, a mechanical mirror, a polarization grating, an optical phased array (OPA), or the like.
  • OPA optical phased array
  • MEMS mirrors the mirror surface rotates or translates in one or two dimensions under electrostatic / piezo / electromagnetic drive.
  • the light emission unit 1 may further include an emission lens 13.
  • the emission lens 13 can be used to expand the emission beam.
  • the emission lens 13 may include a diffractive optical element (DOE) for shaping, separating, or diffusing the emission beam.
  • DOE diffractive optical element
  • the light receiving unit 2 is used to receive and sense the reflected light from the target object in the field of view.
  • the light receiving unit 2 includes a photoelectric sensing device 21, which may include a two-dimensional array composed of a plurality of photodetectors 812 (see FIG. 8).
  • the two-dimensional array can be arranged in a rectangular shape, a circular shape, or any other shape.
  • the photodetector 812 may be an avalanche diode (APD) or a single photon avalanche diode (SPAD).
  • APD avalanche diode
  • SPAD single photon avalanche diode
  • the photodetector 812 measures the power, phase, or time characteristics of the reflected light and generates a corresponding current output.
  • the light receiving unit 2 may further include a receiving lens 22 located in front of the photodetector array on the reflected light propagation path.
  • the receiving lens 22 may include an imaging system lens so that the focus of the reflected light beam is in front of or behind the detection surface of the photodetector array or just above the detection surface.
  • the receiving lens may include an image-side telecentric imaging system lens.
  • the control unit 3 is communicatively coupled with at least one of the light emitting unit 1 and the light receiving unit 2.
  • the control unit 3 can control the light emitted by the light emitting unit 1, adjust the deflection angle of the scanning unit 12 or process the measurement value output by the light receiving unit 2.
  • the control unit 3 may include a feedback control circuit that adjusts the light emitting unit 1 and / or the scanning unit 12 according to the measurement value output by the light receiving unit 2.
  • the control unit 3 may include an integrated circuit (IC), an application specific integrated circuit (ASIC), a microchip, a microcontroller, a central processing unit, a graphics processing unit (GPU), a digital signal processor (DSP), a field programmable gate array ( FPGA) or other circuits suitable for executing instructions or implementing logical operations.
  • the instructions executed by the control unit 3 may be preloaded into an integrated or separate memory.
  • the memory may include random access memory (RAM), read only memory (ROM), hard disk, optical disk, magnetic disk, flash memory, or other volatile or non-volatile memory, and the like.
  • the control unit 3 may include a single or multiple control circuits. In the case of multiple control circuits, each control circuit may have the same or different structure, and interact or cooperate with each other through electrical, magnetic, optical, acoustic, mechanical, and other means.
  • the light emitting unit 1 includes a first light source A and a second light source B, a first mirror M1 and a second mirror M2, and a scanning unit 12.
  • the first mirror M1 includes first and second opposing surfaces.
  • the light emitted by the first light source A reaches the scanning unit 12 after being reflected by the first surface of the first mirror M1.
  • the light emitted by the second light source B is reflected by the second reflecting mirror M2 and reaches the second surface of the first reflecting mirror M1, and transmits to the scanning unit 12 after transmitting through the second surface of the first reflecting mirror M1.
  • FIG. 2a shows a schematic diagram of the optical path of the first embodiment of the light emitting unit according to the present invention.
  • the light emitting unit 1 includes a light source A and a light source B and mirrors M1 and M2 corresponding to the light source A and the light source B, respectively.
  • the light emitted from the light source A and the light source B is irradiated onto the scanning unit 12 after being reflected by M1 and M2, respectively.
  • the scanning unit 12 adjusts the reflection angle of light incident thereon.
  • the mirror M1 has first and second opposing surfaces. The light irradiated on the first surface is totally or mostly reflected. All or most of the light irradiated on the second surface is transmitted through M1.
  • M1 may be a piece of glass in which the first surface is coated with a reflective coating.
  • M1 is a mirror with a specific reflectivity, and its reflectivity is much greater than its transmittance.
  • the reflectance of M1 may be 90%, while the transmittance is 10%. In this way, even if the light from the light source B reflected through M2 and reached M1 is the same as the light intensity directly from the light source A and reached M1, the transmitted light intensity through M1 is much lower than the reflected light intensity through M1.
  • the positions of M1 and M2 are arranged so that the optical paths reflected by M1 and M2, respectively, overlap. This can ensure that the light reaching the scanning unit 12 from the light source A and the light reaching the scanning unit from the light source B fall on the same scanning point on the scanning unit.
  • FIG. 2a shows the case where the second embodiment of the light emitting unit according to the present invention has three light sources.
  • M3 shows the case where the second embodiment of the light emitting unit according to the present invention has three light sources.
  • M3 shows the case where the second embodiment of the light emitting unit according to the present invention has three light sources.
  • M2 may have the same optical properties as described above for M1.
  • the positions of the light sources A and M2 may be adjusted so that the light emitted from the light source A reflects M2 and reaches M1 . Furthermore, the optical path reflected from the light source A via M2 overlaps with the optical path reflected from the light source A via M1.
  • the light emitting unit 1 includes a first light source A and a second light source B, a polarization beam splitting / combining prism (PBS), and a scanning unit 12.
  • the polarization directions of the lights emitted by the first light source A and the second light source B are perpendicular to each other, respectively.
  • the light emitted from the light source A is completely reflected by the PBS and irradiated to the scanning unit 12.
  • the light emitted from the light source B is completely transmitted by the PBS and irradiates the same scanning unit 12.
  • the light paths after the PBS from the light source A and the light source B overlap. In this way, the light reflected from the light source A via the PBS and the light transmitted from the light source B via the PBS reach the same scanning point on the scanning unit.
  • the light source A and the light source B may be configured to work alternately at certain time intervals.
  • the light source A and the light source B may be pulsed light sources.
  • the light source A and the light source B can work alternately at a frequency twice that of the pulsed light source (see FIG. 3b). In this way, the frequency of the pulse light irradiated to the scanning unit is doubled, thereby improving the measurement accuracy of the lidar.
  • the light emitting unit 1 may further include a light source 10, a scanning unit 12, an optical element 14 and a detector assembly 15.
  • the light emitted from the light source 10 is reflected by the scanning unit 12 and reaches the optical element 14, and most of the light is transmitted through the optical element 14 for detecting the target object.
  • a small amount of light is reflected by the optical element 14 and reaches the detector assembly 15.
  • the detector assembly 15 may be an arrangement of multiple identical photodetectors. The light reaching the detector assembly 15 is received by each of the plurality of photodetectors, and outputs photocurrent.
  • the deflection angle of the scanning unit 12 can be calculated according to the photocurrent output by each photodetector 15.
  • the optical element 14 may be a glass plate having a lower reflectivity, for example, the reflectivity is between 0.1% and 3%.
  • the detector assembly 15 may be a four-quadrant photodetector.
  • the four-quadrant photodetector is a photodetector device composed of four photodiodes with the same performance arranged in rectangular coordinates. As the swing angle of the scanning unit 12 is different, the position of the light spot falling on the four-quadrant photodetector changes, and thus the intensity of the light signal received in the four quadrants varies. Based on the difference value, the deflection angle of the scanning unit 12 can be calculated.
  • the lidar system may further include a processing circuit 4 connected to the detector assembly and a control unit 3 for controlling the deflection angle of the scanning unit.
  • the processing circuit 4 calculates the real-time deflection angle of the scanning unit according to the output photocurrent value of the detector assembly.
  • the processing circuit 4 is communicatively coupled with the control unit 3.
  • the processing circuit 4 transmits the calculated deflection angle to the control unit 3.
  • the control unit 3 compares the calculated deflection angle with the expected deflection angle previously applied to the scanning unit 12, from which the error can be determined and compensated.
  • the light emitting unit 1 includes a light source 10, a focusing lens 16, a scanning unit 12 and a collimating lens 17.
  • the scanning unit 12 is a MEMS mirror.
  • the light emitted by the light source 10 is focused on the scanning unit 12 after passing through the focusing lens 16.
  • the focus of the focusing lens 16 may be before the scanning unit 12, on the scanning unit 12, or after the scanning unit 12.
  • the light After being reflected off the scanning unit 12, the light passes through the collimating lens 17 and reaches the object in the field of view to be detected.
  • the diameter of the spot collimated by the collimating lens 17 is larger than the diameter of the scanning unit 12.
  • the focused light incident on the MEMS mirror undergoes deflection at different angles (negative angle, zero angle, and positive angle) and is transmitted through different parts of the collimating lens 17 to detect the difference in the field of view to be measured section.
  • the spot size incident on the MEMS mirror can be reduced, thereby improving the accuracy of the scanning unit 12 in controlling the beam deflection.
  • the collimator lens 17 to expand the beam, the divergence of the light spot is suppressed, the power efficiency is improved, and the detection range is also expanded.
  • the light emitting unit 1 may further include a beam expanding lens 18 on the optical path behind the collimating lens 17 to further expand the size of the light spot and expand the detection range. In this way, even if the MEMS mirror only deflects at a very small angle, it can achieve detection in the full field of view.
  • the light emitting unit 1 may further include a combination of multiple sets of light sources, focusing lens A, and collimating lens.
  • the light emitted by the multiple groups of light sources A-C is focused on the same scanning unit 12 (eg, MEMS mirror) via respective focusing lenses (lenses A1 to A3).
  • the placement between multiple sets of light sources can present a fixed angle.
  • the angle between the light paths of the light source A and the light source B reaching the MEMS mirror is ⁇
  • the angle between the light paths of the light source B and the light source C is also ⁇ .
  • the focal point of each focusing lens may be before the scanning unit 12, above the scanning unit 12, or after the scanning unit 12.
  • the scanning unit 12 is at a fixed deflection angle. Since the light from each light source A-C reaching the scanning unit 12 itself has a certain difference in incidence angle, there is also a certain difference in its reflection angle. The light from each light source A-C is reflected by the scanning unit 12 and directed to different parts of the field of view to be measured. That is, the light emitted by each light source can detect a certain range of the field of view to be measured. Then, the combination of multiple light sources can cover the entire field of view to be measured. As in FIG.
  • the light reflected by the scanning unit 12 can be collimated through corresponding collimating lenses (lenses B1 to B3), respectively, to improve the detection range of the output light of each light source.
  • the spot diameter of the light beam from each light source after passing through the collimating lens is larger than the diameter of the scanning unit 12.
  • the photoelectric sensing device 21 of the light receiving unit 2 further includes a two-dimensional array composed of a plurality of readout circuit units.
  • Each readout circuit unit 814 is coupled to a corresponding photodetector 812 for processing the current signal output by the photodetector 812 (including conversion, amplification, filtering, sampling, comparison, storage, etc.).
  • Each readout circuit unit 814 includes a separate selection switch 816.
  • FIG. 8 shows a schematic structural view of the photoelectric sensor device 21 of the first embodiment of the light receiving unit according to the present invention.
  • the photoelectric sensing device 21 includes a two-dimensional detector array 802 and a two-dimensional readout circuit array 804 and a plurality of electrical connections 806 for coupling the detector array and the readout circuit array.
  • the detector array 802 includes a plurality of photodetectors 812 arranged in rows and columns, which may be, for example, APD.
  • the readout circuit array 804 includes a plurality of readout circuit units 814 arranged in rows and columns.
  • the electrical connector 806 may be coupled to the photodetector 812 and the corresponding readout circuit unit 814 in a bump-bonding or bridge-bonding manner.
  • the substrate material of the detector array 802 may be silicon, germanium, indium gallium arsenic / indium phosphor, mercury cadmium telluride, or the like.
  • the readout circuit array 804 may be based on a CMOS process.
  • FIG. 9a shows a schematic diagram of the working principle of the first embodiment of the light receiving unit according to the present invention.
  • the circuit formed by each photodetector 812 in FIG. 8 and the corresponding readout circuit unit 814 is shown therein.
  • the photodetector 812 receives the reflected light 822 from the target object and generates an output current.
  • the readout circuit unit 814 includes a selection switch 816.
  • the selection switch 816 is turned on or off under the action of the selection control signal 823 to enable or disable the output current of the photodetector 812 from the output signal 824 terminal.
  • the readout circuit unit 814 may also include a transimpedance amplifier 815 for low-noise amplification of the photocurrent (often very weak) output by the photodetector 812.
  • the readout circuit unit 814 may also include one or more of a variable gain amplifier (VGA), a filter, an AC-DC converter, and the like.
  • VGA variable gain amplifier
  • FIG. 9b shows a circuit schematic diagram when the selection switch 816 uses a field effect transistor FET.
  • S d is the drive signal of the photodetector
  • S g is the gate control signal of the FET
  • S out is the output signal of the readout circuit unit.
  • the selection switch 816 may include a MOSFET or JFET with a faster switching speed.
  • the control unit 3 of the laser radar system of the present invention is coupled to the light receiving unit 2.
  • the control unit 3 is configured to: estimate the spot size and angle of the reflected light at the light-receiving surface of the light-receiving unit 2; 814 provides a selection control signal to turn on or off the selection switch 816, thereby enabling or disabling the output signal of the readout circuit unit 814.
  • the control unit 3 is also coupled to the scanning unit 12 and is configured to provide a scanning control signal to the scanning unit 12 to control the deflection angle of the laser beam from the light source 10 of the light emitting unit 1.
  • the spot size and angle of the reflected light at the light receiving surface of the light receiving unit 2 are estimated by the control unit 3 based on the scanning control signal.
  • the readout circuit array 804 includes N transimpedance amplifiers corresponding to N photodetector array units, M post-processing circuit units, and coupled to N An N ⁇ M selection switch array between a transimpedance amplifier and M post-processing circuit BPC units.
  • Each switch unit in the selection switch array can be implemented by FET, MOSFET, BJT, etc.
  • avalanche diodes APD1-N are denoted by 501, 502, 503-50N
  • NXM switch array is denoted by 600
  • post-processing circuit 1-M is denoted by 701, 702, ... 70M-1, 70M
  • TIA is denoted by 400.
  • the signals output by the transimpedance amplifier 815 can be output to the M post-processing circuit units in any combination.
  • the lidar system using the light receiving unit 2 of this structure can realize wide-angle detection.
  • the light receiving unit 2 further includes a receiving lens 22 and an optical filter (not shown) between the receiving lens 22 and the photodetector array 802.
  • the optical filter passes light with a specific wavelength, and blocks background light or other stray light sources.
  • the photoelectric sensing device 21 of the light receiving unit 2 further includes an optical shutter 23.
  • the optical shutter 23 includes a light-transmitting portion and a light-shielding portion. The light reaches each photodetector on the detector array 802 through the light transmitting portion of the optical shutter 23. The position of the light-transmitting portion on the optical shutter 23 is electrically adjustable.
  • the optical shutter 23 may be provided between the receiving lens 22 of the lidar system and the detector array 802.
  • the optical shutter 23 includes a light-transmitting portion 1101 and a light-shielding portion 1102.
  • the reflected light 1111 and 1112 from the target object passes through the receiving lens 22 and then refracted light passes through the light-transmitting portion 1101 to reach the corresponding photodetector 812 on the detector array 802.
  • the interference light 1113 is refracted by the receiving lens 22 and blocked by the light-shielding portion 1102, and cannot reach the detector array 802. In this way, the intensity of interference light reaching the detector array 802 can be suppressed, and the SNR of the output signal can be improved.
  • the incident angles of the reflected lights 1111 and 1112 change with time.
  • the position of the light-transmitting portion 1101 on the optical shutter 23 can be changed accordingly under the control signal to ensure that the required reflected light can always reach the detector array 802 and the interference light 1113 is always suppressed.
  • each micro-shutter unit in the micro-shutter array has a light-blocking component that can be independently controlled electrically. Under the action of the control signal, the light blocking component changes from the closed state to the open state, then the micro shutter unit allows light to pass through.
  • Each micro-shutter unit in the micro-shutter array may be aligned with a corresponding photodetector 812 in the detector array 802.
  • the second implementation of the optical shutter is an LCD-based shutter array.
  • the shutter array includes a plurality of individual LCD elements.
  • Each LCD element may include a glass substrate 901, an ITO electrode 902, a liquid crystal layer 903, a color filter 904, and upper and lower polarizers 905A, 905B.
  • a voltage signal is applied to the liquid crystal molecules in the liquid crystal layer 903 through the ITO electrode 902 to change the polarization direction of light, and in combination with the polarizers 905A and 905B, light transmission or blocking is achieved.
  • the control unit 3 of the laser radar system of the present invention is coupled to the light receiving unit 2.
  • the control unit 3 is configured to: estimate the spot size and angle of the reflected light at the optical shutter 23; based on the estimated spot size and angle, provide an electrical control signal to the optical shutter 23 of the light receiving unit 2 to adjust the optical shutter 23 to transmit light The position of the light part.
  • the control unit 3 is also coupled to the scanning unit 12 and is configured to provide a scanning control signal to the scanning unit 12 to control the deflection angle of the laser beam from the light source 10 of the light emitting unit 1.
  • the spot size and angle of the reflected light at the optical shutter 23 are estimated by the control unit 3 based on the scan control signal.

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Abstract

一种激光雷达系统，包括光发射单元（1），其包括光源（10）和扫描单元（12），扫描单元（12）被构造为以可控制的偏转角度对来自光源（10）的光进行反射，以对目标对象进行扫描；光接收单元（2），用于接收从目标对象反射的光并输出探测值；其中，光接收单元（2）包括光电传感器装置；以及控制单元（3）；其中，从光发射单元（1）发射的光到达目标对象的光路与从目标对象反射的光到达光接收单元（2）的光路是非同轴的。激光雷达系统避免了现有技术中光学传感器中的SPAD探测器的无法消除暗计数的缺点，能够精确测量周围三维空间环境的距离信息，同时能够大幅度抑制背景光和其他杂散光的影响，实现快速高效地对空间光的调制。

Description

一种激光雷达系统 技术领域
本发明涉及一种激光雷达系统，具体地，涉及一种非同轴接收的激光雷达系统。
背景技术
激光雷达(LIDAR)通过向目标对象发射激光光束并接收从目标对象反射的光束来测量目标对象的位置、速度等信息。目前的激光雷达系统通常采用单个光电探测器或者一维光电探测器阵列(一行光电探测器或一列激光探测器)来接收反射光束。光电探测器的受光表面往往比反射光束的光斑尺寸大。在到达光电探测器的受光表面的光中，除了期望的来自目标对象的反射光，还可能存在来自视场(FOV)中其它物体的干扰光(例如，强烈的太阳光，或者来自其它激光雷达系统的光束)。在激光雷达应用于高速、远距离(例如几百米)的场景(例如，高级驾驶辅助系统ADAS)时，到达光电探测器的反射光本身功率很小。在干扰光较强时，光电探测器的输出信号信噪比(SNR)会大大恶化，给激光雷达系统的使用带来了困难。
美国专利申请US2018/0128920A1公开了激光雷达系统的感测单元可以采用探测器(例如雪崩二极管APD或者单光子雪崩二极管SPAD)的二维阵列。阵列大小取决于希望的分辨率、信噪比和希望的检测距离。采用二维探测器阵列可以在一定程度上提高分辨率、信噪比和检测距离，但依然无法消除环境中的干扰光对信噪比的影响。
美国专利申请US2017/0301716A1公开了激光雷达的光学传感器包括SPAD阵列，阵列中每行SPAD探测器和每列SPAD探测器共享一个行选择晶体管和一个列选择晶体管。晶体管可以是MOSFET或BJT。根据预测光斑大小和反射角度在光学传感器阵列中选择相应的行和列，由此减小了预期反射光之外的杂散光的影响。
美国专利申请US2018/0074175A1公开了在激光雷达系统的光电探测器之前设置一个空间光调制器。调节空间光调制器使其形成允许或阻挡光透过的小孔。小孔的位置依据可转向激光的方向来调整。可以有效地阻挡其它环境光，提高信噪比。
发明内容
本发明所要解决的技术问题是提供一种非同轴接收的激光雷达系统，其能够提高分辨率、信噪比，并且显著消除环境中的干扰光对信噪比的影响。
本发明提供的技术方案如下：
根据本发明的一个方面，本发明提供了一种激光雷达系统，包括：光发射单元，用于向目标对象发射光；所述光发射单元包括光源和扫描单元，所述扫描单元被构造为以可控制的偏转角度对来自所述光源的光进行反射，以对目标对象进行扫描；光接收单元，用于接收从目标对象反射的光并输出探测值；所述光接收单元包括光电传感器装置；控制单元，其与所述光发射单元和所述光接收单元通信耦接，其中所述控制单元被构造为对所述光发射单元进行控制，对所述探测值进行处理；并且对所述扫描单元的偏转角度进行控制；其中，从所述光发射单元发射的光到达目标对象的光路与从目标对象反射的光到达所述光接收单元的光路是非同轴的。
根据本发明的光发射单元的第一方面，所述光发射单元包括：第一光源，用于发射第一光；第二光源，用于发射第二光；所述扫描单元，用于以偏转角度对入射到其上的第一光和第二光进行反射；第一反射镜，包括相对的第一表面和第二表面，其中第一光经第一反射镜的第一表面反射后到达所述扫描单元；和第二反射镜，用于对第二光进行反射，其中反射后的第二光经由第一反射镜的第二表面透射穿过第一反射镜后到达所述扫描单元，其中，从第一反射镜反射离开的第一光的光路与从第二反射镜反射离开的第二光的光路重叠。
根据本发明的光发射单元的第二方面，第一方面中所述光发射单元还包括：第三光源，用于发射第三光；和第三反射镜，用于对第三光进行反射，其中，所述第二反射镜包括相对的第一表面和第二表面，所述第二光经所述第二反射镜的第一表面进行反射，反射后的第三光依次经由所述第二反射镜的第二表面和所述第一反射镜的第二表面透射后达到所述扫描单元，其中，从所述第三反射镜反射离开的第三光的光路与从所述第二反射镜反射离开的第二光的光路重叠。
根据本发明的光发射单元的第三方面，第一方面中所述第一光源和所述第二光源为同一光源，所述同一光源的位置可调整为使得在第一位置发射的光经由所述第一反射镜反射后的光路与在第二位置发射的光经由所述第二反射镜反射后的光路重叠。
根据本发明的光发射单元的第四方面，所述光发射单元包括：第 一光源，用于发射第一光；第二光源，用于发射第二光，其中第一光和第二光的偏振方向垂直；所述扫描单元用于以偏转角度对入射到其上的第一光和第二光进行反射；和偏振分束棱镜，被构造为使第一光反射并使第二光透射，反射后的第一光和透射后的第二光经由重叠的光路到达所述扫描单元上的同一位置。
根据本发明的光发射单元的第五方面，光发射单元包括：光源、扫描单元、光学元件，该光学元件用于使入射到其上的来自所述扫描单元的反射光的一部分反射并使另一部分透射通过；光电探测器组件，包括多个光电探测器的排列，用于接收来自光学元件的反射光并输出光电流，其中所述光发射单元还包括处理电路，所述处理电路耦接到所述光电探测器组件，所述处理电路根据所述多个光电探测器中每个光电探测器输出的光电流计算扫描单元的偏转角度。所述控制单元耦接到所述处理电路和所述扫描单元，并被构造为基于计算的偏转角度对所述扫描单元进行调整。
根据本发明的光发射单元的第六方面，光发射单元还包括：聚焦透镜，其位于所述光源和所述扫描单元之间，用于将所述光源发射的光聚焦到所述扫描单元上；以及准直透镜，用于对从所述扫描单元反射的光进行准直。
根据本发明的光发射单元的第七方面，第六方面中光发射单元还包括扩束透镜，所述扩束透镜用于对经由所述准直透镜准直的光进行扩束。
根据本发明的光发射单元的第八方面，第六方面中所述光发射单元还包括：第二光源，用于发射第二光；第二聚焦透镜，位于所述第二光源和扫描单元之间，用于将第二光源发射的光聚焦到扫描单元上；以及第二准直透镜，用于对从扫描单元反射的第二光进行准直，其中来自所述光源的光和来自第二光源的光分别被聚焦到扫描单元的同一位置上。
根据本发明的光接收单元的第一方面，包括光电传感器装置，其包括：二维光电探测器阵列，包括多个光电探测器；和二维读出电路阵列，包括多个读出电路单元；其中，所述多个读出电路单元与所述多个光电探测器一一对应，每个读出电路单元包括选择开关。所述光接收单元的光电传感器装置还包括用于耦接所述二维光电探测器阵列和所述二维读出电路阵列的多个电气连接件。每个电气连接件以块接或桥接方式耦接每个光电探测器和相应的读出电路单元。
根据本发明的光接收单元的第二方面，包括光电传感器装置，其包括：光电探测器阵列，其包括第一数量个光电探测器；和读出电路，包括开关阵列和第二数量个后处理电路，其中所述开关阵列中选择开关的数量为第一数量与第二数量的乘积，其中所述开关阵列用于将第一数量个光电探测器中任意一个的输出连接到第二数量个后处理电路中的任意一个。其中所述读出电路还包括与第一数量个光电探测器一一对应的第一数量个跨阻放大器，每个跨阻放大器用于对从相应光电探测器输出的信号进行放大。
根据本发明的光接收单元的第三方面，包括光电传感器装置，其包括：光电探测器阵列，包括多个光电探测器；和光学快门，包括透光部分和遮光部分，其中光通过所述透光部分到达所述光电探测器阵列的相应光电探测器，其中所述透光部分在光学快门上的位置是电学可调的。
本发明的技术方案的有益技术效果为：避免了现有技术中光学传感器中的SPAD探测器的无法消除暗计数的缺点，能够精确测量周围三维空间环境的距离信息，同时能够大幅度抑制背景光和其他杂散光的影响，实现快速高效地对空间光的调制。
附图说明
为了更清楚地说明本发明具体实施方式或现有技术中的技术方案，下面将对具体实施方式或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图是本发明的一些实施方式，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1是根据本发明的一个实施例的激光雷达系统的结构示意图。
图2a是根据本发明的光发射单元的第一实施例的光路示意图。
图2b是根据本发明的光发射单元的第二实施例的光路示意图。
图2c是根据本发明的光发射单元的第三实施例的光路示意图。
图3a是根据本发明的光发射单元的第四实施例的光路示意图。
图3b是根据本发明的光发射单元的第四实施例产生的脉冲光源频率示意图。
图4是根据本发明的光发射单元的第五实施例的结构示意图。
图5是根据本发明的光发射单元的第六实施例的工作原理图。
图6是根据本发明的光发射单元的第七实施例的工作原理图。
图7是根据本发明的光发射单元的第八实施例的工作原理图。
图8是根据本发明的光接收单元的第一实施例的光电传感装置的结构示意图。
图9a是图8的光接收单元的光电传感装置的工作原理示意图。
图9b是图9a中的选择开关采用场效应管FET时的电路原理图。
图10是根据本发明的光接收单元的第二实施例的光电传感装置的电路原理图。
图11是根据本发明的光接收单元的第三实施例的光电传感装置的结构示意图。
图12是图11中的光学快门的一种工作方式的工作原理图。
图13是图11中的光学快门的另一种工作方式的工作原理图。
具体实施方式
为使本发明实施例的目的、技术方案和优点更加清楚，下面将结合附图对本发明的技术方案进行清楚、完整地描述，显然，所描述的实施例是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
激光雷达系统通过向目标对象发射激光束并探测来自目标对象反射光来测量目标对象的位置、速度等特征。激光雷达系统的测量原理可以分为：三角法测距、基于飞行时间(ToF)的脉冲测距以及相位法测距。
图1示出了根据本发明的一个实施例的激光雷达系统示意图。该激光雷达系统包括光发射单元1、光接收单元2和控制单元3。在非同轴接收的激光雷达系统中，从光发射单元到目标对象的发射光路径与从目标对象到光接收单元的反射光路径并行布置，没有共享部分。
光发射单元1用于向目标对象发射激光束。光发射单元1包括光源10。光源10可以是激光器，例如固态激光器、激光器二极管、高功率激光器。光源10也可以包括LED。光源可以发射不同形式的光，包括脉冲、连续波(CW)和准连续波。激光器可以是垂直腔面发射激光器(VCSEL)或外腔半导体激光器(ECDL)。光源10的工作波长可以是650nm至1150nm、800nm至1000nm、850nm至950nm或者1300nm至1600nm。光发射单元1可以包括与光源10光学耦接的光学组件，用于对光源发出的光束进行准直或聚焦。
光发射单元1还可以包括扫描单元12，用于使来自光源10的光束方向发生偏转，以对目标对象进行扫描，实现更宽的视场(FOV)。扫描单元12可以包括MEMS反射镜、棱镜、机械镜、偏振光栅、光学相控阵(OPA)等。对于MEMS反射镜，反射镜面在静电/压电/电磁驱动下在一维或二维方向上发生旋转或平移。
光发射单元1还可以包括发射透镜13。发射透镜13可以用于对发射光束进行扩束。发射透镜13可以包括衍射光学元件(DOE)，用于对发射光束进行整形、分离或扩散。
光接收单元2用于接收并感测来自视场中目标对象的反射光。光接收单元2包括光电传感装置21，光电传感装置21可以包括由多个光电探测器812构成的二维阵列(参见图8)。该二维阵列可以布置成矩形、圆形或其它任何形状。光电探测器812可以是雪崩二极管(APD)或单光子雪崩二极管(SPAD)。光电探测器812测量反射光的功率、相位或时间特性，并产生相应的电流输出。
光接收单元2还可以包括在反射光传播路径上位于光电探测器阵列前方的接收透镜22。接收透镜22可以包括成像系统透镜，以使得反射光束的焦点在光电探测器阵列的探测表面的前方或后方或者正好位于探测表面之上。特别地，接收透镜可以包括像方远心成像系统透镜。
控制单元3与光发射单元1和光接收单元2中的至少一者通信地耦接。控制单元3可以对光发射单元1发射的光进行控制、调节扫描单元12的偏转角度或者对光接收单元2输出的测量值进行处理。控制单元3可以包括反馈控制电路，其根据光接收单元2输出的测量值对光发射单元1和/或扫描单元12进行调整。
控制单元3可以包括集成电路(IC)、专用集成电路(ASIC)、微芯片、微控制器、中央处理器、图形处理单元(GPU)、数字信号处理器(DSP)、现场可编程门阵列(FPGA)或者其它适合执行指令或实现逻辑操作的电路。由控制单元3执行的指令可以被预加载到集成或单独的存储器中。存储器可以包括随机访问存储器(RAM)、只读存储器(ROM)、硬盘、光盘、磁盘、闪存存储器或其它易失性或非易失性存储器等。控制单元3可以包括单个或多个控制电路。在多个控制电路的情况下，各控制电路可以具有相同或不同的构造，彼此间通过电、磁、光、声、机械等方式交互或者协同操作。
参见图2a,根据本发明的光发射单元的第一实施例，光发射单元1包括第一光源A和第二光源B、第一反射镜M1和第二反射镜M2以及扫描 单元12。第一反射镜M1包括相对的第一表面和第二表面。第一光源A发出的光经第一反射镜M1的第一表面反射后到达扫描单元12。第二光源B发出的光经第二反射镜M2反射后到达第一反射镜M1的第二表面，经第一反射镜M1的第二表面透射后到达扫描单元12。
图2a示出了根据本发明的光发射单元的第一实施例的光路示意图。光发射单元1包括光源A和光源B以及分别与光源A和光源B对应的反射镜M1和M2。从光源A和光源B发射的光分别经过M1和M2的反射后照射到扫描单元12上。扫描单元12对入射到其上的光的反射角度进行调整。反射镜M1具有相对的第一表面和第二表面。照射到第一表面上的光被全部或大部分反射。照射到第二表面上的光全部或大部分透射穿过M1。例如，M1可以是一块玻璃，其中第一表面涂覆有反射涂层。又例如，M1是一块具有特定反射率的反射镜，其反射率远远大于其透射率。例如，M1的反射率可以为90％，而透射率为10％。这样，即便来自光源B经由M2反射后到达M1的光与直接来自光源A并达到M1的光强度相同，经过M1的透射光强度也远远低于经过M1的反射光强度。M1和M2的位置被布置为使得分别经过M1和M2反射后的光路重叠。这可以保证从光源A到达扫描单元12的光与从光源B到达扫描单元的光落在扫描单元上的同一扫描点上。
在通常情况下，仅有光源A工作。当系统检测或得知光接收单元中输出电信号发生饱和(例如，由于光源A发射功率太强、目标对象太近或其它激光雷达系统的干扰)时，可以自动关闭光源A并切换至光源B进行工作，以降低实际输出光功率。
根据图2a的原理的光发射单元可以扩展至包括三个或更多个光源。相应地，增加更多个对应的反射镜。例如，图2b示出了根据本发明的光发射单元的第二实施例具有三个光源的情形。此时，光源C发出的光经过M3反射后，依次透射经过M2和M1，最终到达扫描单元。反射镜M1、M2和M3的位置被布置为使得从相应光源分别照射到其上并被反射后的光路重叠。此时,M2可以具有与以上针对M1描述的相同的光学性质。
在一些实施例中，可以不必实际使用两个或以上的光源。例如，根据本发明的光发射单元的第三实施例，在图2c中，代替使用图2a中的光源B，可以调整光源A和M2的位置使得从光源A发射的光经过M2反射后到达M1。并且，从光源A经由M2反射后的光路与从光源A经由M1反射后的光路重叠。
参见图3a，根据本发明的光发射单元的第四实施例，光发射单元1 包括第一光源A和第二光源B、偏振分束/合束棱镜(PBS)以及扫描单元12。第一光源A和第二光源B分别发射的光的偏振方向彼此垂直。从光源A发射的光被PBS完全反射并照射到扫描单元12。从光源B发射的光被PBS完全透射并照射到同一扫描单元12。从光源A和光源B经过PBS后的光路重叠。这样，从光源A经由PBS反射的光与从光源B经由PBS透射的光到达扫描单元上的同一扫描点。
光源A和光源B可以被配置为按照一定时间间隔交替工作。光源A和光源B可以是脉冲光源。光源A和光源B可以按照其脉冲光源频率的2倍的频率交替工作(如图3b)。这样照射到扫描单元的脉冲光频率被提高一倍，从而提高了激光雷达的测量精度。
参见图4，根据本发明的光发射单元的第五实施例，光发射单元1还可以包括光源10、扫描单元12、光学元件14和探测器组件15。从光源10发射的光经扫描单元12反射后到达光学元件14，其中大部分的光透射通过光学元件14，以用于对目标对象进行探测。少量的光经由光学元件14反射后到达探测器组件15。探测器组件15可以是多个相同光电探测器的排列。到达探测器组件15的光被多个光电探测器中的每个接收，并输出光电流。根据各个光电探测器15输出的光电流可以计算出扫描单元12的偏转角度。
例如，光学元件14可以是具有较低反射率的玻璃板，其反射率比如在0.1％至3％之间。例如，探测器组件15可以是四象限光电探测器。四象限光电探测器是由四个性能完全相同的光电二极管按照直角坐标要求排列而成的光电探测器件。随着扫描单元12的摆动角度的不同，落在四象限光电探测器的光斑的位置发生变化，由此四个象限上接收的光信号强度产生差异。根据该差异值可以计算出扫描单元12的偏转角度。
在激光雷达系统中，采用图4所述的光发射单元1能够对扫描单元12的偏转角度进行实时监控。如图4所示，激光雷达系统还可以包括与探测器组件连接的处理电路4和用于控制扫描单元的偏转角度的控制单元3。处理电路4根据探测器组件的输出光电流值计算出扫描单元的实时偏转角度。处理电路4与控制单元3通信耦接。处理电路4将计算出的偏转角度传递给控制单元3。控制单元3将计算的偏转角度与先前施加到扫描单元12的预期偏转角度进行比较，可以由此确定误差并对误差进行补偿。
参见图5，根据本发明的光发射单元的第六实施例，光发射单元1 包括光源10、聚焦透镜16、扫描单元12和准直透镜17。该扫描单元12为MEMS反射镜。光源10发出的光经聚焦透镜16后聚焦在扫描单元12上。聚焦透镜16的焦点可以在扫描单元12之前、扫描单元12上或者扫描单元12之后。光在扫描单元12上反射离开后穿过准直透镜17，到达待检测视场中的对象。经准直透镜17准直后的光斑直径大于扫描单元12的直径。
如图5所示，入射到MEMS反射镜上的聚焦光在经历不同角度(负角度、零角度和正角度)偏转后经由准直透镜17的相应不同部分透射，从而检测待测视场中的不同部分。使用聚焦透镜16，入射到MEMS反射镜上的光斑尺寸可以减小，从而提高了扫描单元12对光束偏转进行控制的精度。而使用准直透镜17进行扩束，则抑制了光斑的发散，提高功率效率，也扩大了检测范围。
参见图6，根据本发明的光发射单元的第七实施例，光发射单元1还可以在准直透镜17后的光路上包括一个扩束透镜18，以进一步扩大光斑的尺寸，扩大检测范围。这样，即便MEMS反射镜只进行很小角度的偏转，也能够实现全视场范围内的检测。
在图5的原理基础上，参见图7，根据本发明的光发射单元的第八实施例，光发射单元1还可以包括多组光源、聚焦透镜A和准直透镜的组合。如图7所示，多组光源A-C发出的光分别经由各自的聚焦透镜(透镜A1～A3)聚焦在同一个扫描单元12(例如，MEMS反射镜)上。多组光源之间的放置可以呈现一固定夹角。例如，光源A和光源B分别到达MEMS反射镜的光路之间的夹角为α，而光源B和光源C的光路之间的夹角也为α。同样，各个聚焦透镜的焦点可以在扫描单元12之前、扫描单元12之上或者扫描单元12之后。
在扫描单元12进行扫描的某个时刻，扫描单元12处于一固定的偏转角度。由于各光源A-C到达扫描单元12的光本身具有一定的入射角度差异，因而其反射角度也存在一定的差异。来自各光源A-C的光经扫描单元12反射后指向待测视场中的不同部分。亦即，每个光源发射的光能够对一定范围的待测视场进行检测。那么，通过多个光源的组合即可覆盖全部待测视场。同图5中一样，经扫描单元12反射后的光可以分别经过相应的准直透镜(透镜B1～B3)进行准直，以提高每个光源的输出光的检测范围。来自各个光源的光束经过准直透镜之后的光斑直径大于扫描单元12的直径。
参见图8，根据本发明的光接收单元的第一实施例，光接收单元2 的光电传感装置21还包括由多个读出电路单元构成的二维阵列。每个读出电路单元814与相应的光电探测器812耦接，用于对光电探测器812输出的电流信号进行处理(包括转换、放大、滤波、采样、比较和存储等)。每个读出电路单元814包括单独的选择开关816。
图8示出了根据本发明的光接收单元的第一实施例的光电传感装置21的结构示意图。光电传感装置21包括二维探测器阵列802和二维读出电路阵列804以及用于耦接探测器阵列和读出电路阵列的多个电气连接件806。探测器阵列802包括以行列方式布置的多个光电探测器812，其例如可以是APD。相应地，读出电路阵列804包括以行列方式布置的多个读出电路单元814。电气连接件806可以以块接(Bump-bonding)或者桥接(Bridge-bonding)方式耦接光电探测器812和相应的读出电路单元814。探测器阵列802的衬底材料可以是硅、锗、铟镓砷/铟磷、碲镉汞等。读出电路阵列804可以基于CMOS工艺。
图9a示出了根据本发明的光接收单元的第一实施例的工作原理示意图。其中示出了图8中的每个光电探测器812与相应的读出电路单元814构成的电路。在驱动信号821作用下，光电探测器812接收来自目标对象的反射光822并产生输出电流。读出电路单元814包括选择开关816。选择开关816在选择控制信号823作用下被接通或断开，以启用或禁止光电探测器812的输出电流从输出信号824端输出。读出电路单元814还可以包括跨阻放大器815，用于对光电探测器812输出的光电流(往往很微弱)进行低噪声放大。读出电路单元814还可以包括可变增益放大器(VGA)、滤波器、交直流转换器等中的一个或多个。
图9b示出了当选择开关816采用场效应管FET时的电路原理图。其中S d是光电探测器的驱动信号，S g是FET的栅极控制信号，S out是读出电路单元的输出信号。优选地，选择开关816可以包括开关速度较快的MOSFET或者JFET。
本发明的激光雷达系统的控制单元3与光接收单元2耦接。控制单元3被配置为：估计在光接收单元2的受光表面处反射光的光斑大小和角度；基于所估计的光斑大小和角度，向光接收单元2的读出电路阵列的各读出电路单元814提供选择控制信号以接通或断开选择开关816，由此使能或禁止读出电路单元814的输出信号。进一步地，控制单元3还与扫描单元12耦接，并被配置为向扫描单元12提供扫描控制信号，以控制来自光发射单元1的光源10的激光束的偏转角度。在光接收单元2的受光表面处反射光的光斑大小和角度是由控制单元3基于扫描控制 信号来估计的。
参见图10，根据本发明的光接收单元的第二实施例，读出电路阵列804包括与N个光电探测器阵列单元对应的N个跨阻放大器、M个后处理电路单元以及耦接在N个跨阻放大器和M个后处理电路BPC单元之间的N×M选择开关阵列。选择开关阵列中每个开关单元可以由FET、MOSFET、BJT等实现。图10中雪崩二极管APD1-N分别用标号501,502,503-50N表示，NXM开关阵列用600表示，后处理电路1-M分别用标号701,702，…70M-1,70M表示，TIA用标号400表示。
通过使用N×M选择开关阵列，可以将跨阻放大器815输出的信号以任意组合的形式输出到M个后处理电路单元中。采用这种结构的光接收单元2的激光雷达系统能够实现广角探测。
在一些情况下，光接收单元2还包括接收透镜22和位于接收透镜22与光电探测器阵列802之间的光学滤波器(未示出)。光学滤波器使具有特定波长的光通过，而阻隔背景光或其它杂散光源的光。
根据本发明的光接收单元的第三实施例，光接收单元2的光电传感装置21还包括光学快门23。光学快门23包括透光部分和遮光部分。光通过光学快门23的透光部分到达探测器阵列802上的各光电探测器。光学快门23上透光部分的位置是电学可调的。
如图11所示，光学快门23可以设置在激光雷达系统的接收透镜22与探测器阵列802之间。光学快门23包括透光部分1101和遮光部分1102。来自目标对象的反射光1111和1112经由接收透镜22后折射光穿过透光部分1101到达探测器阵列802上的相应光电探测器812。干扰光1113经接收透镜22折射后被遮光部分1102阻挡，而无法到达探测器阵列802。这样，可以抑制到达探测器阵列802的干扰光强度，提高输出信号的SNR。
在激光雷达对视场内的物体进行扫描的情况下，反射光1111和1112的入射角度随时间变化。光学快门23上透光部分1101的位置可以在控制信号作用下随之变化，以保证所需的反射光总是能到达探测器阵列802，而总是抑制干扰光1113。
光学快门的实现方式之一是基于MEMS的微快门阵列。如图12所示，微快门阵列中每个微快门单元具有可独立电控的挡光组件。在控制信号作用下，挡光组件从关闭状态变为打开状态，则该微快门单元允许光透过。微快门阵列中的每个微快门单元可以与探测器阵列802中的相应光电探测器812对准。
光学快门的实现方式之二是基于LCD的快门阵列。如图13所示，快 门阵列包括多个单独的LCD元件。每个LCD元件可以包括玻璃基板901、ITO电极902、液晶层903、滤色器904和上下偏光片905A,905B。通过ITO电极902向液晶层903中的液晶分子施加电压信号，改变光的极化方向，结合偏光片905A,905B来实现光的透过或遮挡。
本发明的激光雷达系统的控制单元3与光接收单元2耦接。控制单元3被配置为：估计在光学快门23处反射光的光斑大小和角度；基于所估计的光斑大小和角度，向光接收单元2的光学快门23提供电学控制信号以调整光学快门23上透光部分的位置。进一步地，控制单元3还与扫描单元12耦接，并被配置为向扫描单元12提供扫描控制信号，以控制来自光发射单元1的光源10的激光束的偏转角度。在光学快门23处反射光的光斑大小和角度是由控制单元3基于扫描控制信号来估计的。
以上所述实施例，仅为本发明的具体实施方式，用以说明本发明的技术方案，而非对其限制，本发明的保护范围并不局限于此，尽管参照前述实施例对本发明进行了详细的说明，本领域的普通技术人员应当理解：任何熟悉本技术领域的技术人员在本发明揭露的技术范围内，其依然可以对前述实施例所记载的技术方案进行修改或可轻易想到变化，或者对其中部分技术特征进行等同替换；而这些修改、变化或者替换，并不使相应技术方案的本质脱离本发明实施例技术方案的精神和范围，都应涵盖在本发明的保护范围之内。因此，本发明的保护范围应所述以权利要求的保护范围为准。

Claims (67)

  1. 一种激光雷达系统，包括：
    光发射单元，用于向目标对象发射光；其中，所述光发射单元包括光源和扫描单元，所述扫描单元被构造为以可控制的偏转角度对来自所述光源的光进行反射，以对目标对象进行扫描；
    光接收单元，用于接收从目标对象反射的光并输出探测值；其中，所述光接收单元包括光电传感器装置；
    控制单元，其与所述光发射单元和所述光接收单元通信耦接，其中所述控制单元被构造为对所述光发射单元进行控制，对所述探测值进行处理；并且对所述扫描单元的偏转角度进行控制；
    其中，从所述光发射单元发射的光到达目标对象的光路与从目标对象反射的光到达所述光接收单元的光路是非同轴的。
  2. 根据权利要求1所述的激光雷达系统，其中所述扫描单元可以选自包括以下的组：反射镜、棱镜、机械镜、偏振光栅和光学相控阵。
  3. 根据权利要求1所述的激光雷达系统，其中所述光发射单元还包括发射透镜，所述发射透镜用于对从所述扫描单元反射的光进行整形、分离或扩束。
  4. 根据权利要求1所述的激光雷达系统，其中所述光发射单元包括光源和光学组件，其中光学组件被构造为对所述光源发出的光进行准直或聚焦。
  5. 根据权利要求1所述的激光雷达系统，其中所述光接收单元的光电传感装置包括光电探测器。
  6. 根据权利要求5所述的激光雷达系统，其中所述光接收单元还包括接收透镜，其中从目标对象反射的光经所述接收透镜聚焦后到达所述光电探测器，所述接收透镜的焦点在所述光电探测器表面的前方、之上或者后方。
  7. 根据权利要求1所述的激光雷达系统，其中，所述光发射单元包括：
    第一光源，用于发射第一光；
    第二光源，用于发射第二光；
    所述扫描单元，用于以偏转角度对入射到其上的第一光和第二光进行反射；
    第一反射镜，包括相对的第一表面和第二表面，其中第一光经第一反射镜的第一表面反射后到达所述扫描单元；和
    第二反射镜，用于对第二光进行反射，其中反射后的第二光经由第一反射镜的第二表面透射穿过第一反射镜后到达所述扫描单元，
    其中，从第一反射镜反射离开的第一光的光路与从第二反射镜反射离开的第二光的光路重叠。
  8. 根据权利要求7所述的激光雷达系统，其中所述第一反射镜的反射率远大于其透射率。
  9. 根据权利要求7所述的激光雷达系统，其中所述第一反射镜的第一表面涂覆有反射涂层。
  10. 根据权利要求7所述的激光雷达系统，其中所述光发射单元还包括：
    第三光源，用于发射第三光；和
    第三反射镜，用于对第三光进行反射，
    其中，所述第二反射镜包括相对的第一表面和第二表面，所述第二光经所述第二反射镜的第一表面进行反射，反射后的第三光依次经由所述第二反射镜的第二表面和所述第一反射镜的第二表面透射后达到所述扫描单元，
    其中，从所述第三反射镜反射离开的第三光的光路与从所述第二反射镜反射离开的第二光的光路重叠。
  11. 根据权利要求7所述的激光雷达系统，其中所述第一光源和所述第二光源响应于反馈信号以可切换的方式进行操作。
  12. 根据权利要求7所述的激光雷达系统，其中，所述第一光源和所述第二光源为同一光源，所述同一光源的位置可调整为使得在第一位置发射的光经由所述第一反射镜反射后的光路与在第二位置发射的光经由所述第二反射镜反射后的光路重叠。
  13. 根据权利要求12所述的激光雷达系统，其中所述同一光源的位置是响应于反馈信号可调整的。
  14. 根据权利要求7所述的激光雷达系统，其中，所述控制单元基于所述探测值确定反馈信号，并基于所述反馈信号对第一光源和第二光源进行调整。
  15. 根据权利要求1所述的激光雷达系统，其中所述光发射单元包括：
    第一光源，用于发射第一光；
    第二光源，用于发射第二光，其中第一光和第二光的偏振方向垂直；
    所述扫描单元用于以偏转角度对入射到其上的第一光和第二光进行反射；和
    偏振分束棱镜，被构造为使第一光反射并使第二光透射，反射后的第一光和透射后的第二光经由重叠的光路到达所述扫描单元上的同一位置。
  16. 根据权利要求15所述的激光雷达系统，其中所述第一光源和所述第二光源按照一定频率交替工作。
  17. 根据权利要求16所述的激光雷达系统，其中所述第一光源和所述第二光源是脉冲光源，所述一定频率是脉冲光源的重复频率的两倍。
  18. 根据权利要求1所述的激光雷达系统，其中所述光发射单元还包括：
    光学元件，用于使入射到其上的来自所述扫描单元的反射光的一部分反射并使另一部分透射通过；
    光电探测器组件，包括多个光电探测器的排列，用于接收来自光学元件的反射光并输出光电流。
  19. 根据权利要求18所述的激光雷达系统，其中所述光发射单元还包括处理电路，所述处理电路耦接到所述光电探测器组件，所述处理电路根据所述多个光电探测器中每个光电探测器输出的光电流计算扫描单元的偏转角度。
  20. 根据权利要求19所述的激光雷达系统，其中所述控制单元耦接到所述处理电路和所述扫描单元，并被构造为基于计算的偏转角度对所述扫描单元进行调整。
  21. 根据权利要求18所述的激光雷达系统，其中所述光电探测器组件是四象限光电探测器。
  22. 根据权利要求18所述的激光雷达系统，其中所述光学元件的透射率远大于其反射率。
  23. 根据权利要求1所述的激光雷达系统，其中所述光发射单元还包括：
    聚焦透镜，其位于所述光源和所述扫描单元之间，用于将所述光源发射的光聚焦到所述扫描单元上；以及
    准直透镜，用于对从所述扫描单元反射的光进行准直。
  24. 根据权利要求23所述的激光雷达系统，其中所述聚焦透镜的焦点在所述扫描单元之前、之上或者之后。
  25. 根据权利要求23所述的激光雷达系统，其中经所述准直透镜准直后的光的光斑直径大于所述扫描单元的直径。
  26. 根据权利要求23所述的激光雷达系统，其中所述光发射单元还包括扩束透镜，所述扩束透镜用于对经由所述准直透镜准直的光进行扩束。
  27. 根据权利要求26所述的激光雷达系统，其中通过所述扫描单元以不同偏转角度反射的光经所述准直透镜的对应不同部分进行准直。
  28. 根据权利要求23所述的激光雷达系统，其中所述光发射单元还包括：
    第二光源，用于发射第二光；
    第二聚焦透镜，位于所述第二光源和扫描单元之间，用于将第二光源发射的光聚焦到扫描单元上；以及
    第二准直透镜，用于对从扫描单元反射的第二光进行准直，
    其中来自所述光源的光和来自第二光源的光分别被聚焦到扫描单元的同一位置上。
  29. 根据权利要求28所述的激光雷达系统，其中所述第二聚焦透镜的焦点在所述扫描单元之前、之上或者之后。
  30. 根据权利要求28所述的激光雷达系统，其中所述第二准直透镜准直后的光的光斑直径大于所述扫描单元的直径。
  31. 根据权利要求1所述的激光雷达系统，其中所述光接收单元的光电传感器装置包括：
    二维光电探测器阵列，包括多个光电探测器；和
    二维读出电路阵列，包括多个读出电路单元；
    其中，所述多个读出电路单元与所述多个光电探测器一一对应，每个读出电路单元包括选择开关。
  32. 根据权利要求31所述的激光雷达系统,其中所述光接收单元的光电传感器装置还包括用于耦接所述二维光电探测器阵列和所述二维读出电路阵列的多个电气连接件。
  33. 根据权利要求32所述的激光雷达系统，其中每个电气连接件以块接或桥接方式耦接每个光电探测器和相应的读出电路单元。
  34. 根据权利要求31所述的激光雷达系统，其中所述多个光电探测器是雪崩光电二极管。
  35. 根据权利要求31所述的激光雷达系统，其中所述多个读出电路单元基于CMOS工艺。
  36. 根据权利要求31所述的激光雷达系统，其中每个读出电路单元还包括跨阻放大器，从每个光电探测器输出的光电流通过相应的跨阻放大器和选择开关被输出。
  37. 根据权利要求31所述的激光雷达系统，其中所述选择开关是MOSFET或JFET。
  38. 根据权利要求31所述的激光雷达系统，其中所述选择开关基于选择控制信号被接通或断开。
  39. 根据权利要求38所述的激光雷达系统，其中所述选择控制信号基于在相应光电探测器处接收到的光的光斑大小和角度中的至少一者。
  40. 根据权利要求1所述的激光雷达系统，其中所述光接收单元的光电传感器装置包括：
    光电探测器阵列，其包括第一数量个光电探测器；和
    读出电路，包括开关阵列和第二数量个后处理电路，其中所述开关阵列中选择开关的数量为第一数量与第二数量的乘积，其中所述开关阵列用于将第一数量个光电探测器中任意一个的输出连接到第二数量个后处理电路中的任意一个。
  41. 根据权利要求40所述的激光雷达系统，其中所述读出电路还包括与第一数量个光电探测器一一对应的第一数量个跨阻放大器，每个跨阻放大器用于对从相应光电探测器输出的信号进行放大。
  42. 根据权利要求40所述的激光雷达系统，其中所述开关阵列中的每个选择开关是FET、MOSFET、BJT中的至少一者。
  43. 根据权利要求40所述的激光雷达系统，其中还包括光学滤波器，所述光学滤波器位于所述光电探测器阵列之上。
  44. 根据权利要求1所述的激光雷达系统，其中所述光接收单元的光电传感器装置包括：
    光电探测器阵列，包括多个光电探测器；和
    光学快门，包括透光部分和遮光部分，其中光通过所述透光部分到达所述光电探测器阵列的相应光电探测器，
    其中所述透光部分在所述光学快门上的位置是电学可调的。
  45. 根据权利要求44所述的激光雷达系统，其中所述光学快门是基于MEMS的微快门阵列。
  46. 根据权利要求45所述的激光雷达系统，其中所述微快门阵列中的每个微快门单元包括可独立电控的遮光组件。
  47. 根据权利要求45所述的激光雷达系统，其中所述微快门阵列中的每个微快门单元与光电探测器阵列中的相应光电探测器对准。
  48. 根据权利要求44所述的激光雷达系统，其中所述光学快门是基于LCD的快门阵列，所述基于LCD的快门阵列包括多个单独的LCD元件，每个LCD元件与所述光电探测器阵列中的相应光电探测器对准。
  49. 根据权利要求44所述的激光雷达系统，其中所述透光部分在所述光学快门上的位置是基于入射到所述光学快门上的光的光斑大小和位置中的至少一者来调节的。
  50. 一种光发射单元，包括：
    第一光源，用于发射第一光；
    第二光源，用于发射第二光；
    扫描单元，用于以偏转角度对入射到其上的第一光和第二光进行反射；
    第一反射镜，包括相对的第一表面和第二表面，其中第一光经第一反射镜的第一表面反射后到达所述扫描单元；和
    第二反射镜，用于对第二光进行反射，其中反射后的第二光经由第一反射镜的第二表面透射穿过第一反射镜后到达所述扫描单元，
    其中，从第一反射镜反射离开的第一光的光路与从第二反射镜反射离开的第二光的光路重叠。
  51. 根据权利要求50所述的光发射单元还包括：
    第三光源，用于发射第三光；和
    第三反射镜，用于对第三光进行反射，
    其中，所述第二反射镜包括相对的第一表面和第二表面，所述第二光经所述第二反射镜的第一表面进行反射，反射后的第三光依次经 由所述第二反射镜的第二表面和所述第一反射镜的第二表面透射后达到所述扫描单元，
    其中，从所述第三反射镜反射离开的第三光的光路与从所述第二反射镜反射离开的第二光的光路重叠。
  52. 根据权利要求50所述的光发射单元，其中，所述第一光源和所述第二光源为同一光源，所述同一光源的位置可调整为使得在第一位置发射的光经由所述第一反射镜反射后的光路与在第二位置发射的光经由所述第二反射镜反射后的光路重叠。
  53. 一种光发射单元，包括：
    第一光源，用于发射第一光；
    第二光源，用于发射第二光，其中第一光和第二光的偏振方向垂直；
    扫描单元用于以偏转角度对入射到其上的第一光和第二光进行反射；和
    偏振分束棱镜，被构造为使第一光反射并使第二光透射，反射后的第一光和透射后的第二光经由重叠的光路到达所述扫描单元上的同一位置。
  54. 一种光发射单元，包括：
    光源；
    扫描单元，所述扫描单元被构造为以可控制的偏转角度对来自所述光源的光进行反射，以对目标对象进行扫描；
    光学元件，该光学元件用于使入射到其上的来自所述扫描单元的反射光的一部分反射并使另一部分透射通过；
    光电探测器组件，包括多个光电探测器的排列，用于接收来自光学元件的反射光并输出光电流。
  55. 根据权利要求54所述的光发射单元，其中所述光发射单元还包括处理电路，所述处理电路耦接到所述光电探测器组件，所述处理电路根据所述多个光电探测器中每个光电探测器输出的光电流计算扫描单元的偏转角度。
  56. 一种光发射单元，包括：
    光源；
    扫描单元，所述扫描单元被构造为以可控制的偏转角度对来自所述光源的光进行反射，以对目标对象进行扫描；
    聚焦透镜，其位于所述光源和所述扫描单元之间，用于将所述光源发射的光聚焦到所述扫描单元上；以及
    准直透镜，用于对从所述扫描单元反射的光进行准直。
  57. 根据权利要求56所述的光发射单元，还包括扩束透镜，所述扩束透镜用于对经由所述准直透镜准直的光进行扩束。
  58. 根据权利要求56所述的光发射单元，还包括：第二光源，用于发射第二光；第二聚焦透镜，位于所述第二光源和扫描单元之间，用于将第二光源发射的光聚焦到扫描单元上；以及第二准直透镜，用于对从扫描单元反射的第二光进行准直，其中来自所述光源的光和来自第二光源的光分别被聚焦到扫描单元的同一位置上。
  59. 一种光接收单元，包括光电传感器装置，其包括：
    二维光电探测器阵列，包括多个光电探测器；和
    二维读出电路阵列，包括多个读出电路单元；
    其中，所述多个读出电路单元与所述多个光电探测器一一对应，每个读出电路单元包括选择开关。
  60. 根据权利要求59所述的光接收单元,其中所述光接收单元的光电传感器装置还包括用于耦接所述二维光电探测器阵列和所述二维读出电路阵列的多个电气连接件。
  61. 根据权利要求60所述的光接收单元，其中每个电气连接件以块接或桥接方式耦接每个光电探测器和相应的读出电路单元。
  62. 根据权利要求59所述的光接收单元，其中每个读出电路单元还包括跨阻放大器，从每个光电探测器输出的光电流通过相应的跨阻放大器和选择开关被输出。
  63. 一种光接收单元，包括光电传感器装置，其包括：
    光电探测器阵列，其包括第一数量个光电探测器；和
    读出电路，包括开关阵列和第二数量个后处理电路，其中所述开关阵列中选择开关的数量为第一数量与第二数量的乘积，其中所述开关阵列用于将第一数量个光电探测器中任意一个的输出连接到第二数量个后处理电路中的任意一个。
  64. 根据权利要求63所述的光接收单元，其中所述读出电路还包括与第一数量个光电探测器一一对应的第一数量个跨阻放大器，每个跨阻放大器用于对从相应光电探测器输出的信号进行放大。
  65. 一种光接收单元，包括光电传感器装置，其包括：
    光电探测器阵列，包括多个光电探测器；和
    光学快门，包括透光部分和遮光部分，其中光通过所述透光部分到达所述光电探测器阵列的相应光电探测器，
    其中所述透光部分在光学快门上的位置是电学可调的。
  66. 根据权利要求65所述的激光雷达系统，其中所述光学快门是基于LCD的快门阵列，所述基于LCD的快门阵列包括多个单独的LCD元件，每个LCD元件与所述光电探测器阵列中的相应光电探测器对准。
  67. 根据权利要求65所述的激光雷达系统，其中所述透光部分在所述光学快门上的位置是基于入射到所述光学快门上的光的光斑大小和位置中的至少一者来调节的。
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