WO2020142870A1 - 一种测距装置 - Google Patents

一种测距装置 Download PDF

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Publication number
WO2020142870A1
WO2020142870A1 PCT/CN2019/070638 CN2019070638W WO2020142870A1 WO 2020142870 A1 WO2020142870 A1 WO 2020142870A1 CN 2019070638 W CN2019070638 W CN 2019070638W WO 2020142870 A1 WO2020142870 A1 WO 2020142870A1
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WIPO (PCT)
Prior art keywords
light
area
light source
optical path
detector
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/CN2019/070638
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English (en)
French (fr)
Inventor
董帅
洪小平
黄淮
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SZ DJI Technology Co Ltd
Original Assignee
SZ DJI Technology Co Ltd
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.)
Filing date
Publication date
Application filed by SZ DJI Technology Co Ltd filed Critical SZ DJI Technology Co Ltd
Priority to CN201980005208.3A priority Critical patent/CN112219130B/zh
Priority to PCT/CN2019/070638 priority patent/WO2020142870A1/zh
Publication of WO2020142870A1 publication Critical patent/WO2020142870A1/zh
Priority to US17/369,549 priority patent/US20210341610A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • 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
    • G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves
    • G01S17/18—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves wherein range gates are used
    • 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
    • G01S7/4811—Constructional features, e.g. arrangements of optical elements common to transmitter and receiver
    • G01S7/4812—Constructional features, e.g. arrangements of optical elements common to transmitter and receiver transmitted and received beams following a coaxial path
    • 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
    • G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves
    • 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
    • G01S7/484—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
    • 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
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F30/00—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors
    • H10F30/20—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors the devices having potential barriers, e.g. phototransistors
    • H10F30/21—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors the devices having potential barriers, e.g. phototransistors the devices being sensitive to infrared, visible or ultraviolet radiation
    • H10F30/22—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors the devices having potential barriers, e.g. phototransistors the devices being sensitive to infrared, visible or ultraviolet radiation the devices having only one potential barrier, e.g. photodiodes
    • H10F30/225—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors the devices having potential barriers, e.g. phototransistors the devices being sensitive to infrared, visible or ultraviolet radiation the devices having only one potential barrier, e.g. photodiodes the potential barrier working in avalanche mode, e.g. avalanche photodiodes

Definitions

  • the invention relates to the technical field of laser radar, in particular to a distance measuring device.
  • Lidar is a radar system that emits laser beams to detect target position, velocity and other characteristic quantities.
  • the light sensor of the lidar can convert the acquired light pulse signal into an electrical signal, and obtain the time information corresponding to the electrical signal based on the comparator, thereby obtaining the distance information between the lidar and the target.
  • coherent detection generally uses the polarization characteristics of laser light and the interference detection of the outgoing light and the return light. This scheme requires more polarization to ensure the return light polarization characteristics
  • the unit, light source and signal need to be modulated and demodulated, etc., which is expensive and suitable for remote detection of weak signals; direct detection mostly adopts the system structure of separation of the receiving and sending axes, and this solution requires more lens structures.
  • the triangulation method is mostly used, which has many lenses and high optical cost, and is more suitable for close-range high-precision detection ( ⁇ um level); for the structure of the transceiver coaxial, the phase method or the pulse method is mostly used .
  • the edge source laser (EEL) is generally used as the light source, and the avalanche diode (APD) is used as the receiving element.
  • EEL and APD are used as key devices to realize the generation and detection of the laser beam.
  • APD is generally round or square, and using EEL laser, the echo spot is elliptical, approximately rectangular, and the APD circular photosensitive surface is difficult to match the echo spot, resulting in a low signal-to-noise ratio and reduced ranging range.
  • the current distance measuring device has the above-mentioned various problems that need to be solved urgently.
  • a first aspect of the present invention provides a distance detection device, including:
  • Light source used to emit light pulses
  • a transceiving element for collimating the light pulse emitted by the light source and condensing at least part of the returned light reflected by the detection object from the light pulse;
  • the detector is placed on the same side of the transceiving element as the light source, and is used to receive at least part of the return light condensed by the transceiving element, and convert the received return light into an electrical signal, which is used For measuring the distance between the detection object and the distance detection device;
  • the optical path changing element is placed on the same side of the transceiver element as the light source and the detector, and is used to combine the outgoing optical path of the optical pulse and the receiving optical path of the detector;
  • the optical path changing element includes a first area, the first area is used to transmit or reflect part of the optical pulse from the light source to the transceiving element, and the first area receives the optical pulse
  • the solid angle is 20%-40% of the solid angle received by the detector for the returned light.
  • the numerical aperture of the transceiver element is 0.15-0.5.
  • the first area is used to transmit part of the light pulse from the light source to the transceiving element
  • the optical path changing element further includes a second area, the second area is used to transmit and receive the light The part of the returned light converged by the element is reflected to the detector;
  • the first area is used to reflect part of the light pulse from the light source to the transceiving element
  • the optical path changing element further includes a second area, the second area is used to converge the transceiving element The part of the returned light is transmitted to the detector.
  • the projected area of the first region on a plane perpendicular to the optical axis of the light pulse is 20%-40% of the projected area of the second region on the plane.
  • the optical path changing element is used to output 60%-85% of the total energy of the light pulses emitted by the light source to the transceiver element.
  • the energy of the return light received by the detector accounts for more than 60% of the return light energy received by the optical path changing element.
  • the receiving solid angle of the first region to the optical pulse is approximately the distance between the projection area of the first region on a plane perpendicular to the optical axis of the optical pulse and the plane and the light source Ratio of squares
  • the effective solid angle of the detector for the returned light is less than or equal to the difference between the solid angle of the detector for the returned light and the solid angle of the first region for the optical pulse.
  • the shape of the projection of the first region on a plane perpendicular to the optical axis of the light pulse matches the shape of the light spot formed by the light pulse on the plane;
  • the shape of the first area matches the shape of the light emitting surface of the light source.
  • the shape of the projection of the first region on a plane perpendicular to the optical axis of the light pulse and the shape of the light spot formed on the plane by the light pulse are matching circles, ellipses, and trapezoids Or rectangular
  • the shape of the first area and the shape of the light spot are matching circles, ellipses, trapezoids or rectangles.
  • the light source includes a laser diode, and the aperture of the first region in the direction of the fast axis of the laser diode is greater than the aperture in the direction of the slow axis of the laser diode.
  • the first region includes a first end and a second end located on both sides of the optical axis, wherein the first end is closer to the light source than the second end and is parallel to the light
  • the caliber of the second end in the direction of the optical axis of the pulse is larger than the caliber of the first end.
  • the first area is trapezoidal.
  • the projected area of the first region on a plane perpendicular to the optical axis of the light pulse is smaller than the area of the light spot formed by the light pulse on the plane.
  • the transceiver element includes at least one of a lens group, an aspheric lens, and a gradient index lens.
  • the optical path changing element is disposed on one side of the light pulse emitted by the light source, and/or the optical path changing element is located within the focal length of the transceiver element.
  • the surface of the optical path changing element is flat or curved.
  • one of the detector and the light source is placed on the focal plane of the transceiver element, and the other is placed on one side of the optical axis of the transceiver element.
  • the optical path changing element is placed between the transceiving element and the light source, allowing transmission of light pulses emitted by the light source, and allowing the return light passing through the transceiving element to be reflected to the detection Device
  • the optical path changing element is placed on the same side of the transceiving element and the light source, allowing light pulses emitted by the light source to be reflected, and allowing the return light passing through the transceiving element to exit to the detector.
  • the center of the first area coincides with the optical axis of the light pulse emitted by the light source.
  • the center of the first area is offset from the optical axis of the transceiver element.
  • the optical path changing element is specifically a reflective surface provided in the first area.
  • the first area is set as a transmission opening, or the first area includes a light-transmitting substrate;
  • the second area is provided as a reflective surface.
  • the first area includes a light-transmitting substrate; wherein,
  • the surface of the first area facing and/or facing away from the light source is coated with an antireflection coating; or,
  • the surface of the light path changing element facing the light source is coated with an antireflection coating; or,
  • a polarizing film is provided on the first area, and the polarizing direction of the polarizing film is the same as the polarizing direction of the emitted light pulse.
  • both the first area and the second area include a transparent substrate coated with a polarizing film, the polarizing direction of the polarizing film is the same as the polarizing direction of the emitted light pulse, and the A non-reciprocal polarization rotation device is provided on one side of the element, so that the polarization direction of the optical pulse is perpendicular to the polarization direction of the return light passing through the non-reciprocal polarization rotation device.
  • the non-reciprocal polarization rotating device includes a Faraday rotating mirror.
  • the non-reciprocal polarization rotation device is used to align the polarization direction of the light pulse emitted by the light source with the polarization direction of the emitted light pulse after collimation at 45 degrees.
  • the optical path changing element is placed on the same side of the transceiving element and the light source, and the effective aperture of the transceiving element is larger than the effective aperture of the optical path changing element.
  • the central axis of the light source is perpendicular to the central axis of the detector.
  • the distance detection device includes a plurality of the light sources, a plurality of the detectors corresponding to the plurality of light sources, and a plurality of light path changing elements corresponding to the plurality of light sources and the detectors .
  • the light source includes at least one edge exit laser
  • the detector includes at least one avalanche diode for receiving at least part of the return light condensed by the transceiver element, and converting the received return light into electricity signal.
  • the shape of the photosensitive surface of the avalanche diode matches the shape of the light spot of the returning light.
  • the size of the photosensitive surface of the avalanche diode is larger than the size of the light spot of the return light, and the difference between the two sizes is equal to or greater than the assembly error.
  • the photosensitive surface of the avalanche diode has an ellipse or ellipse-like shape.
  • the ellipse-like shape is a rectangle with rounded corners.
  • the light source includes a plurality of edge-emitting laser line arrays formed by a regular arrangement of edge-emitting lasers
  • the detector includes a plurality of avalanche diode line arrays formed by a regular arrangement of avalanche diodes
  • the multiple edge exit laser line arrays correspond to the avalanche diode line arrays in one-to-one correspondence.
  • the light source includes a plurality of edge-emitting laser surface arrays formed by a regular arrangement of edge-emitting lasers
  • the detector includes a plurality of avalanche diode surface arrays formed by a regular arrangement of avalanche diodes
  • the edge exit laser surface array corresponds to the avalanche diode surface array in one-to-one correspondence.
  • the present invention provides a distance measuring device in which the lidar coaxial transceiver mirror structure is used in the distance measuring device, and the pulse laser TOF principle/frequency shift measurement/phase shift measurement is used in conjunction with the beam scanning system.
  • Distance detection field Compared with coherent detection, it has the advantages of simple structure, low cost, and high cost performance; compared with the triangle method of direct detection, it has fewer optical components, coaxial transmission and reception, and simple installation and adjustment; compared with the phase method of direct detection, no light source modulation is required 3. The range is wide and the response speed is fast. It is more suitable for scanning detection.
  • FIG. 1 is a schematic diagram of a lidar transceiver coaxial system in a distance measuring device provided by an embodiment of the present invention
  • FIG. 2 is a schematic diagram of light emitted by an edge-emitting laser diode in a distance measuring device provided by an embodiment of the present invention
  • 3A-3E are schematic structural diagrams of an optical path changing element in a distance measuring device provided by an embodiment of the present invention.
  • FIG. 4 is a schematic diagram of a lidar transceiver coaxial system in a distance measuring device provided by another embodiment of the present invention.
  • FIG. 5 is a schematic diagram of a coaxial system of a lidar transceiver in a distance measuring device provided by another embodiment of the present invention.
  • FIG. 6 is a schematic diagram of a lidar transceiver coaxial system in a distance measuring device provided by another embodiment of the present invention.
  • FIG. 7 is a schematic diagram of a lidar transceiver coaxial system in a distance measuring device according to another embodiment of the present invention.
  • FIG. 8 is a schematic diagram of an embodiment of a distance measuring device provided by an embodiment of the present invention using a coaxial optical path;
  • FIG. 9 shows a schematic structural diagram of an EEL in a distance measuring device provided by an embodiment of the present invention.
  • FIG. 10 shows a cross-sectional view of the EEL in FIG. 9 along the B-B direction;
  • FIG. 11 is a schematic diagram showing the shape of an APD photosensitive surface in a distance measuring device provided by an embodiment of the present invention.
  • FIG. 12 shows a schematic diagram of the shape of the APD photosensitive surface in the distance measuring device provided by another embodiment of the present invention.
  • FIG. 13 is a schematic diagram showing the relationship between the APD photosensitive surface and the return light spot in the distance measuring device provided by another embodiment of the present invention.
  • FIG. 14 shows a schematic diagram of the shape of the photosensitive surface of the APD array in the distance measuring device provided by an embodiment of the present invention
  • FIG. 15 shows a schematic diagram of the shape of the photosensitive surface of the APD array in the distance measuring device provided by another embodiment of the present invention.
  • the edge light emitting laser (EEL) is generally used as the light source, and the avalanche diode (APD) is used as the receiving element, because its light-emitting area is flat and narrow, such as 75um ⁇ 10um, or 150um ⁇ 10um.
  • the spot size is also rectangular.
  • the spot formed on the focal plane is also rectangular.
  • the photosensitive surface size of the APD is larger than the spot size, but it is not too large.
  • the size of the photosensitive surface increases, the electrical noise caused by surface leakage current, etc., also increases. The increase of noise will deteriorate the noise characteristics of the system and reduce the ranging characteristics of the system; when the size of the photosensitive surface of the APD increases, the cost will increase.
  • the photosensitive surface of APD is generally set to be round or square, and the diameter of the circle cannot be simply adjusted to make the photosensitive surface and the echo spot better match.
  • the present invention provides a distance measuring device.
  • the following first describes the overall structure of the distance measuring device in the embodiment of the present invention with reference to FIG. 8, and then The transmission and reception coaxial system in the distance measuring device will be described in detail.
  • FIG. 8 shows a schematic diagram of an embodiment of the distance measuring device of the present invention using a coaxial optical path.
  • the distance measuring device 200 includes a distance measuring module 210 including a light source 203 (which may include a transmitting circuit), a collimating element 204, a detector 205 (which may include a receiving circuit, a sampling circuit, and an arithmetic circuit) and an optical path changing element 206.
  • the distance measuring module 210 is used to emit a light beam and receive back light, and convert the back light into an electrical signal.
  • the light source 203 can be used to emit a sequence of light pulses. In one embodiment, the light source 203 may emit a sequence of laser pulses.
  • the laser beam emitted by the light source 203 is a narrow-bandwidth beam with a wavelength outside the visible light range.
  • the collimating element 204 is disposed on the exiting light path of the light source, and is used to collimate the light beam emitted from the light source 203 and collimate the light beam emitted from the light source 203 into parallel light to the scanning module.
  • the collimating element is also used to converge at least a part of the return light reflected by the detection object.
  • the collimating element 204 may be a collimating lens or other element capable of collimating the light beam.
  • the optical path changing element 206 is used to combine the transmitting optical path and the receiving optical path in the distance measuring device before the collimating element 204, so that the transmitting optical path and the receiving optical path can share the same collimating element, so that the optical path More compact.
  • the light source 203 and the detector 205 may respectively use respective collimating elements, and the optical path changing element 206 is disposed on the optical path behind the collimating element.
  • the light path changing element can use a small-area mirror to emit The optical path and the receiving optical path are merged.
  • the light path changing element may also use a reflective mirror with a through hole, where the through hole is used to transmit the outgoing light of the light source 203, and the reflective mirror is used to reflect the return light to the detector 205. In this way, it is possible to reduce the blocking of the return light by the support of the small mirror in the case of using the small mirror.
  • the optical path changing element is offset from the optical axis of the collimating element 204. In some other implementations, the optical path changing element may also be located on the optical axis of the collimating element 204.
  • the distance measuring device 200 further includes a scanning module 202.
  • the scanning module 202 is placed on the exit optical path of the distance measuring module 210.
  • the scanning module 202 is used to change the transmission direction of the collimated light beam 219 emitted through the collimating element 204 and project it to the outside environment, and project the return light to the collimating element 204 .
  • the returned light is converged on the detector 205 via the collimating element 204.
  • the scanning module 202 may include at least one optical element for changing the propagation path of the light beam, wherein the optical element may change the propagation path of the light beam by reflecting, refracting, diffracting, etc. the light beam.
  • the scanning module 202 includes a lens, a mirror, a prism, a galvanometer, a grating, a liquid crystal, an optical phased array (Optical Phased Array), or any combination of the above optical elements.
  • at least part of the optical element is moving, for example, the at least part of the optical element is driven to move by a driving module, and the moving optical element can reflect, refract or diffract the light beam to different directions at different times.
  • multiple optical elements of the scanning module 202 may rotate or vibrate about a common axis 209, and each rotating or vibrating optical element is used to continuously change the direction of propagation of the incident light beam.
  • the multiple optical elements of the scanning module 202 may rotate at different rotation speeds, or vibrate at different speeds.
  • at least part of the optical elements of the scanning module 202 can rotate at substantially the same rotational speed.
  • the multiple optical elements of the scanning module may also rotate around different axes.
  • the multiple optical elements of the scanning module may also rotate in the same direction, or rotate in different directions; or vibrate in the same direction, or vibrate in different directions, which is not limited herein.
  • the scanning module 202 includes a first optical element 214 and a driver 216 connected to the first optical element 214.
  • the driver 216 is used to drive the first optical element 214 to rotate about a rotation axis 209 to change the first optical element 214 The direction of the collimated light beam 219.
  • the first optical element 214 projects the collimated light beam 219 to different directions.
  • the angle between the direction of the collimated light beam 219 after the first optical element changes and the rotation axis 209 changes as the first optical element 214 rotates.
  • the first optical element 214 includes a pair of opposed non-parallel surfaces through which the collimated light beam 219 passes.
  • the first optical element 214 includes a prism whose thickness varies along at least one radial direction.
  • the first optical element 214 includes a wedge-angle prism, aligning the straight beam 219 for refraction.
  • the scanning module 202 further includes a second optical element 215 that rotates about a rotation axis 209.
  • the rotation speed of the second optical element 215 is different from the rotation speed of the first optical element 214.
  • the second optical element 215 is used to change the direction of the light beam projected by the first optical element 214.
  • the second optical element 115 is connected to another driver 217, and the driver 217 drives the second optical element 215 to rotate.
  • the first optical element 214 and the second optical element 215 may be driven by the same or different drivers, so that the first optical element 214 and the second optical element 215 have different rotation speeds and/or rotations, thereby projecting the collimated light beam 219 to the outside space Different directions can scan a larger spatial range.
  • the controller 218 controls the drivers 216 and 217 to drive the first optical element 214 and the second optical element 215, respectively.
  • the rotation speeds of the first optical element 214 and the second optical element 215 can be determined according to the area and pattern expected to be scanned in practical applications.
  • Drives 216 and 217 may include motors or other drives.
  • the second optical element 215 includes a pair of opposed non-parallel surfaces through which the light beam passes. In one embodiment, the second optical element 215 includes a prism whose thickness varies along at least one radial direction. In one embodiment, the second optical element 215 includes a wedge angle prism.
  • the scanning module 202 further includes a third optical element (not shown) and a driver for driving the third optical element to move.
  • the third optical element includes a pair of opposed non-parallel surfaces through which the light beam passes.
  • the third optical element includes a prism whose thickness varies along at least one radial direction.
  • the third optical element includes a wedge angle prism. At least two of the first, second and third optical elements rotate at different rotational speeds and/or turns.
  • each optical element in the scanning module 202 can project light into different directions, such as the direction and direction 213 of the projected light 211, thus scanning the space around the distance measuring device 200.
  • the light 211 projected by the scanning module 202 hits the detection object 201, a part of the light is reflected by the detection object 201 to the distance measuring device 200 in a direction opposite to the projected light 211.
  • the returned light 212 reflected by the detection object 201 passes through the scanning module 202 and enters the collimating element 204.
  • the detector 205 and the light source 203 are placed on the same side of the collimating element 204.
  • the detector 205 is used to convert at least part of the returned light passing through the collimating element 204 into an electrical signal.
  • each optical element is coated with an antireflection coating.
  • the thickness of the AR coating is equal to or close to the wavelength of the light beam emitted by the light source 203, which can increase the intensity of the transmitted light beam.
  • a filter layer is coated on the surface of an element on the beam propagation path in the distance measuring device, or a filter is provided on the beam propagation path to transmit at least the wavelength band of the beam emitted by the light source and reflect Other bands to reduce the noise caused by ambient light to the receiver.
  • the light source 203 may include a laser diode through which laser pulses in the order of nanoseconds are emitted.
  • the laser pulse receiving time may be determined, for example, by detecting the rising edge time and/or the falling edge time of the electrical signal pulse. In this way, the distance measuring device 200 can calculate the TOF using the pulse reception time information and the pulse emission time information, thereby determining the distance between the detection object 201 and the distance measuring device 200.
  • the distance and orientation detected by the distance measuring device 200 can be used for remote sensing, obstacle avoidance, mapping, modeling, navigation, and the like.
  • the distance measuring device of the embodiment of the present invention can be applied to a mobile platform, and the distance measuring device can be installed on the platform body of the mobile platform.
  • a mobile platform with a distance measuring device can measure the external environment, for example, measuring the distance between the mobile platform and obstacles for obstacle avoidance and other purposes, and performing two-dimensional or three-dimensional mapping on the external environment.
  • the mobile platform includes at least one of an unmanned aerial vehicle, a car, a remote control car, a robot, and a camera.
  • the distance measuring device is applied to an unmanned aerial vehicle, the platform body is the fuselage of the unmanned aerial vehicle.
  • the platform body When the distance measuring device is applied to an automobile, the platform body is the body of the automobile.
  • the car may be a self-driving car or a semi-automatic car, and no restriction is made here.
  • the platform body When the distance measuring device is applied to a remote control car, the platform body is the body of the remote control car.
  • the platform body When the distance measuring device is applied to a robot, the platform body is a robot.
  • the distance measuring device is applied to a camera, the platform body is the camera itself.
  • the distance measuring device includes a light source 1 for emitting light pulses;
  • the transceiving element 4 is used to collimate the light pulse 2 emitted by the light source and converge at least part of the return light reflected by the detection object from the light pulse;
  • the detector 6 is placed on the same side of the transceiving element as the light source, and is used to receive at least part of the return light 5 converged by the transceiving element, and convert the received return light into an electrical signal.
  • the signal is used to measure the distance between the detection object and the distance detection device;
  • the optical path changing element 3 is placed on the same side of the transceiving element as the light source and the detector, and is used to combine the outgoing optical path of the optical pulse and the receiving optical path of the detector;
  • the optical path changing element includes a first area, the first area is used to transmit or reflect part of the optical pulse from the light source to the transceiving element, and the first area receives the optical pulse
  • the solid angle is 20%-40% of the solid angle received by the detector for the returned light.
  • the light source and the detector can refer to the relevant introductions in the above embodiments of the present invention, and the following focuses on the transceiver element 4 and the optical path changing element 3 in detail.
  • the optical path changing element 3 may be an optical element with a flat surface, as shown in FIG. 1, or an optical element with a curved surface, as shown in FIGS. 6 and 7 , Is not limited to a certain kind.
  • the optical path changing element 3 uses a mirror with a concave surface, which can shorten the receiving focal length of the detector, the entire system will be more compact in the receiving direction, and the application of the concave mirror makes the lens system for receiving and transmitting different , The FOV of the receiving system is larger and the received optical signal is stronger.
  • the optical path changing element 3 requires that the receiving solid angle of the light pulse in the first area be 20%-40% of the receiving solid angle of the detector for the returned light regardless of whether a planar or curved optical element is used .
  • This setting not only considers the effective area of the optical path changing element 3 to transmit or reflect the emitted light pulse, but also considers the area of the optical path changing element 3 to reflect or transmit the returned light, comprehensively considering the ratio between the two, through this setting
  • the signal ratio between the optical pulse transmitted or reflected on the optical path changing element 3 to the transceiving element and the light pulse received by the detector after the reflected light reflected by the detection object passes through the optical path changing element 3 can be optimized , So that the detection device achieves the longest detection distance.
  • the solid angle means that the light pulse takes the vertex of the vertebral body as the spherical center to make a spherical surface, and the ratio of the area intercepted by the vertebral body on the spherical surface to the square of the spherical radius, the unit is spherical degree.
  • the solid angle can be approximated as the ratio of the plane area of the vertebral body to the square of the side length of the vertebral body.
  • the receiving solid angle of the first region to the light pulse is the distance between the projected area of the first region on a plane perpendicular to the optical axis of the light pulse and the plane and the light source Ratio of squares. In the absence of special instructions, the solid angle mentioned below refers to this explanation and explanation.
  • the solid angle is also related to the numerical aperture of the transceiving element.
  • the numerical aperture of the transceiving element is 0.15-0.5.
  • the optical path changing element 3 may further include a second area, the first area is used to transmit part of the light pulse from the light source to the transceiving element, and the second area is used to transmit and receive the light The part of the returned light converged by the element is reflected to the detector, as shown in Figure 1;
  • the optical path changing element 3 may further include a second area, the first area is used to reflect part of the light pulse from the light source to the transceiving element, and the second area is used to place the transceiving element The part of the condensed return light is transmitted to the detector.
  • the center of the first area coincides with the optical axis of the light pulse emitted by the light source to ensure that enough light pulses can be transmitted or reflected by the optical path changing element 3.
  • the center of the first area deviates from the optical axis of the transceiving element, for example, in an embodiment of the present invention, the optical path changing element 3 is inclined, and the optical path changing element 3 and the transceiving element The angle between the optical axes is approximately 45°.
  • the optical path changing element 3 includes a first area and a second area, wherein the first area is used to transmit part of the light pulse from the light source to the transceiver element, The second area is used to reflect part of the returned light condensed by the transceiving element to the detector.
  • the light pulse 2 emitted by the light source 1 passes through the optical path changing element 3 to the transceiving element (such as a quasi-direct receiving lens) )4. After collimating, hit the detection object; the reflected light 5 reflected by the detection object is received by the quasi-direct receiving lens, and reaches the detector 6 through the semi-inverted half lens.
  • the received signal is then subjected to some amplification, filtering, and algorithm processing to complete Detection of target distance and angle.
  • the light source 1 and the detector 6 are respectively located at the backward focus of the transceiving element (such as a quasi-direct receiving lens).
  • the quasi-direct receiving lens is a special cemented lens group or an aspheric lens or a gradient index lens, which serves as both
  • the collimating lens emitted by the laser, as the receiving mirror for returning light has the advantages of small aberration, low cost and easy processing.
  • the optical path changing element 3 is located in the backward focal length of the quasi-direct receiving lens, has a transmission effect on the emitted laser light, and has a reflection effect on the return light. By using different solid angles of the lens, the direction of transmitting and receiving signals is separated.
  • the transceiving element 4 may include at least one of a lens group, an aspheric lens, and a gradient index lens.
  • the lens group may include a combination of several concave lenses and several convex lenses, the number and combination of which are not limited to a certain one, and can be set according to actual needs.
  • the transceiver element 4 uses a convex lens.
  • the specific shape of the optical path changing element 3 is not limited to any one, as long as it can transmit the emitted laser light and reflect the received signal, it can be applied to this embodiment.
  • the shape of the projection of the first region on a plane perpendicular to the optical axis of the light pulse matches the shape of the light spot formed by the light pulse on the plane, so as to make the light pulse as many as possible Project the first area to increase the measurement range.
  • the shape of the projection of the first area on a plane perpendicular to the optical axis of the light pulse and the shape of the light spot formed on the plane by the light pulse are matching circles, ellipses, trapezoids, or rectangles.
  • the projected area of the first area on a plane perpendicular to the optical axis of the light pulse is smaller than the area of the light spot formed by the light pulse on the plane, so that the first area is effectively sufficient Use.
  • the shape of the first area matches the shape of the light-emitting surface of the light source, and the shape of the light-emitting surface of the light source is the same as the shape of the light spot formed by the light pulse on a plane perpendicular to the optical axis.
  • the transmission window of the optical path changing element 3, that is, the angular aperture and shape opened to the light source 1 or the detector 6 match the selected light source spot.
  • the optical path changing element 3 The equivalent transmission window is an elongated shape corresponding to the length direction; if the light source is a circular spot, the optical path changing element 3 is also matched to a circle; if the light source is an elliptical spot, the optical path changing element 3, etc.
  • the effective transmission window is also matched to the ellipse corresponding to the longitudinal direction; if the light source is a trapezoidal spot, the equivalent transmission window of the optical path changing element 3 is also matched to the trapezoid corresponding to the longitudinal direction.
  • the light source is an edge-emitting laser diode
  • the divergence angles of the radiated light field in the fast axis and slow axis directions are different, as shown in FIG. 2, where A-A1 is the fast axis direction, B- B1 is the direction of the slow axis.
  • A-A1 is the fast axis direction
  • B- B1 is the direction of the slow axis.
  • the half-widths of the divergence angles are 15-30° and 6-15°, respectively, and the radiation spot is elliptical. Therefore, the opening of the reflector is set to match the ellipse Shape or rectangle, can get better performance.
  • the aperture of the first area in the direction of the fast axis of the laser diode is larger than the aperture of the direction of the slow axis of the laser diode, so that the first area and the edge emitting laser diode Match the light spot.
  • the first region includes a lower end and an upper end located on both sides of the optical axis, wherein the lower end is closer to the light source than the upper end, as shown in FIG. 1, and is parallel to the optical axis of the optical pulse
  • the caliber of the upper end is larger than that of the lower end.
  • the actual area and shape of the first area (transmission window) of the optical path changing element 3 are related to the tilt angle, specifically, the effective solid angle emitted by the light source along the optical axis direction is determined by overlapping the oblique optical path changing element 3 ; Because of the oblique placement, the equivalent transmission window of the mirror is similar to a trapezoid, with the upper part being wide and the bottom being narrow; and the greater the tilt angle, the greater the width-to-narrow ratio of the trapezoid.
  • the projected area of the first region on a plane perpendicular to the optical axis of the light pulse is 20%-40% of the projected area of the second region on the plane.
  • the optical path changing element is used to output 60%-85% of the total energy of the light pulses emitted by the light source to the transceiver element.
  • the energy of the return light received by the detector accounts for more than 60% of the return light energy received by the optical path changing element.
  • the ratio of the received signal lost by the transmission window through the lens is considered.
  • the intensity distribution of the laser light source and the actual emission ratio are also considered.
  • the optical path changing element 3 is placed in the backward focal length of the quasi-direct receiving lens, the closer to the lens, the better (the processing tolerance and assembly error sensitivity will be reduced).
  • the detector is placed on the focal plane of the transceiver element, the light source is placed on one side of the optical axis of the transceiver element, or the light source is placed on the transceiver element On the focal plane of, the detector is placed on the side of the optical axis of the transceiver element.
  • the optical path changing element is placed between the transceiving element and the light source, as shown in FIGS. 1, 4, and 7, allowing the transmission of light pulses emitted by the light source and passing through the transceiving element Of the returned light is reflected to the detector, and in this arrangement, the effective aperture of the transceiving element is smaller than the effective aperture of the optical path changing element.
  • the optical path changing element is placed on the same side of the transceiving element and the light source, allowing light pulses emitted by the light source to be reflected, and allowing the return through the transceiving element
  • the basic structure and principle are the same as the examples shown in Fig. 1, Fig. 4 and Fig. 7, except that the positions of the detector and the light source are reversed, and the volume of the optical path changing element 3 becomes smaller, which reflects the outgoing light pulse.
  • the signal of the back light passes through, and the basic characteristics remain unchanged.
  • the optical path changing element 3 may be an optical element with a flat surface, as shown in FIG. 1, or an optical element with a curved surface, as shown in FIG. 6 and As shown in Figure 7.
  • the coaxial optical path is described through the above examples.
  • the specific structure of the optical path changing element 3 and the example of selecting other types of optical elements are described below. It should be noted that as long as the following embodiments and the above implementations The examples do not contradict each other, and the following embodiments can be applied to the above examples.
  • the optical path changing element 3 includes a first area and a second area.
  • the following uses the first area as a transmission window and the second area as a reflection window as an example.
  • the first area includes a light-transmitting substrate; the surface of the first area facing and/or facing away from the light source is coated with an antireflection film; or, the surface of the optical path changing element faces the light source An antireflection coating is applied; or, a polarizing film is provided on the first area, and the polarizing direction of the polarizing film is the same as the polarizing direction of the emitted light pulse.
  • the implementation of the above solution is as follows:
  • the optical path changing element 3 is set as an aperture mirror:
  • the optical path changing element 3 has an opening in the middle, and the size of the hole is determined by the inclination angle of the mirror, the spatial distribution of the light field radiated by the light source, and the effective numerical aperture of the lens, as shown in FIG. 3A, where 30 is the light The axis, 31 is the non-reflecting surface of the mirror, 32 is the reflecting surface of the color mirror, 33 is the middle opening area, 301 is the plane perpendicular to the optical axis, and FIG.
  • 3A is the projection of the optical path changing element 3 on the 301 surface, opening
  • the projected shape of the area 33 matches the shape of the light emitting surface of the light source used: the size in both directions is related to the intensity characteristics of the light field radiated by the light source.
  • the optical path changing element is placed obliquely to the optical axis, the emitted laser light exits through the middle opening of the opening area 33, the returned wave signal is reflected to the detector through the reflection surface 32, and the returned light is actually received by the detector About 65-75%.
  • the reflective surface of the optical path changing element can also be coated with an antireflective film, which can be a dielectric film or a metal film, the reflectivity is greater than 90%, and the wavelength range is 880nm to 950nm; the non-reflecting surface of the optical path changing element can be processed to reduce the reflectivity (To eliminate the influence of T0 caused by stray light), the corresponding area should be coated with ink, black paint, glue or other coatings with reduced reflectance, which can also be treated with antireflection coating.
  • an antireflective film which can be a dielectric film or a metal film, the reflectivity is greater than 90%, and the wavelength range is 880nm to 950nm
  • the non-reflecting surface of the optical path changing element can be processed to reduce the reflectivity (To eliminate the influence of T0 caused by stray light)
  • the corresponding area should be coated with ink, black paint, glue or other coatings with reduced reflectance, which can also be treated with antireflection coating.
  • the optical path changing element 3 is set as an antireflection mirror: this example can reduce the influence of T0 caused by stray light caused by the aperture surface and the non-reflection surface, and the lens processing is simpler;
  • the first region 33 in the middle of the optical path changing element is coated with an antireflection film, without openings, and the transmittance is greater than 80% (for example, greater than 98% ), the reflective surface 32 is coated with a high reflection film, the reflectivity is greater than 80% (for example, greater than 90%), and the wavelength range is 880nm to 950nm; the shape of the coating area 33 matches the divergence of the light source used.
  • the optical path changing element 3 is placed obliquely to the optical axis, the emitted laser light exits through the 33 intermediate coating, the return light is reflected to the detector through the reflective surface 32, and the return light is actually received by the detector at about 60 to 80%.
  • the optical path changing element 3 no longer has a hole, and the non-reflective surface 31 of the optical path changing element is coated with an antireflection coating over the entire surface.
  • FIG. 3D shows the reflective surface of the optical path changing element, the reflective surface 32 High-reflective coating, antireflection coating on the first area 33, the film reflectivity and wavelength requirements are unchanged; in this example, the optical path changing element 3 is placed obliquely to the optical axis, the emitted laser is emitted through the 33 intermediate coating, and the return light is reflected The face 32 is reflected until the detector is received.
  • the optical path changing element 3 is no longer apertured, and the entire surface of the non-reflective surface 31 is not coated.
  • FIG. 3D shows the non-reflective surface of the optical path changing element, and the reflective surface 32 is coated with a highly reflective film.
  • the first area 33 is coated with an antireflection coating, and the film reflectivity and band requirements are unchanged; in this example, in this example, the optical path changing element 3 is placed obliquely to the optical axis, and a polarized light source with a degree of polarization greater than 95% can be selected for the emitted laser (generally
  • the semiconductor lasers are all linearly polarized light), through the Fresnel reflection law, the polarization direction of the emitted laser light is parallel to the paper surface (P light), then more than 96% of the emitted laser light will exit through the 33 intermediate coating, and the return light will pass through the reflection The face 32 is reflected until the detector is received.
  • FIG. 3D is The optical path changes the emitting surface of the element, in which the wavelength band and reflectivity of the high-reflection film are unchanged.
  • the Fresnel reflection principle can also be used to reduce the reflection of the outgoing laser light by the non-reflective surface 31.
  • the optical path changing element is placed obliquely to the optical axis, and a polarized light source with a degree of polarization greater than 95% (generally semiconductor lasers are linearly polarized light) can be used for the emitted laser, and the polarization direction of the emitted laser is P polarization state (P light),
  • P light P polarization state
  • the Fresnel reflection law the reflection of the uncoated region 33 to the emitted laser light is reduced, and the return light is reflected to the detector through the reflection surface 32 to be received.
  • the material refractive index of the glass of the optical path changing element 3 is greater than 1.72, and the corresponding Brewster angle is greater than 60 degrees.
  • the optical path changing element 3 is set as a polarizer, stray light will be reduced a lot by the setting, and the structure of the polarizer is simple;
  • the optical path changing element is selected as a polarizer or polarizer, the polarized light transmittance needs to be >90%, no hole is opened in the middle of the optical path changing element, polarizer or polarizer
  • the polarization direction is 35 (parallel to the paper surface P light), the non-reflective surface and the reflective surface may not be coated.
  • the optical path changing element 3 is placed obliquely to the optical axis, and a polarized light source with a degree of polarization greater than 95% (generally semiconductor lasers are linearly polarized light) can be used to emit laser light.
  • the polarization direction of the emitted laser light is the same as the polarization direction of the polarizer (P light ), at this time, more than 90% of the emitted laser light will be emitted through the polarizer, and the return light will be reflected by the reflective surface 32 to the detector to be received.
  • the echo is no longer polarized light, and the signal reflected by the polarizer has more than 45% of the returned light.
  • the optical path changing element 3 is selected to be a light-transmitting material, such as ordinary glass, and the middle region 33 is plated with a polarizing film (without openings), so that the polarization direction is the same as that of the outgoing laser The light transmittance is high.
  • the non-reflective surface 31 is not coated, and the reflective surface 32 is coated with a high-reflective film, and the film reflectivity and band requirements are unchanged;
  • the optical path changing element 3 is placed obliquely to the optical axis, and the inclination angle needs to be close to the polarization angle of the optical path changing element.
  • a polarized light source with a degree of polarization greater than 95% can be selected (general semiconductor lasers are linearly polarized light).
  • the polarization direction of the emitted laser light is the same as the polarization direction 35 of the polarizing film. At this time, more than 90% of the emitted laser light will exit through the polarizer, and the return light will be reflected by the reflection surface 32 to the detector and received.
  • the echo is no longer polarized light, and part of the reflected light can still be reflected to the detector through the area 33, so that the detected echo power can be increased.
  • the return light reflected by the reflecting surface 32 can be controlled to 65% or more.
  • the optical path changing element 3 is set as a polarizer + non-reciprocal polarization rotating device (Faraday rotator or 1/4 piece), through the setting, the stray light will be reduced a lot, the received signal strength will be increased a lot, but the lens is increased , The cost increases and the structure becomes complicated;
  • both the first area and the second area include a light-transmitting substrate coated with a polarizing film, the polarizing direction of the polarizing film is the same as the polarizing direction of the emitted light pulse, and A non-reciprocal polarization rotation device is provided on one side of the transceiver element, so that the polarization direction of the optical pulse is perpendicular to the polarization direction of the return light passing through the non-reciprocal polarization rotation device.
  • the light radiated by the laser is linearly polarized light
  • the optical path changing element is selected as a polarizer or a polarizer.
  • the polarization transmission direction is the same as the polarization direction of the laser radiated light, and the polarized light transmittance must be >80%.
  • the non-reflective surface and the reflective surface may not be coated; a Faraday rotator 7 is placed behind the collimating lens, the corresponding wavelength is 905 nm, and the aperture is not smaller than the lens aperture.
  • the Faraday mirror is used to collimate the polarization direction of the light pulse emitted by the light source and the polarization direction of the emitted light pulse after collimation to 45 degrees.
  • the polarization direction of the echo after passing through the Faraday rotator mirror is perpendicular to the polarization direction of the outgoing laser beam due to the effect of the Faraday rotator mirror. Therefore, it will be reflected by the mirror to the detector and detected .
  • a polarized light source with a degree of polarization greater than 95% can be used for the emitted laser.
  • the polarized direction of the emitted laser is the same as the polarization transmission direction of the optical path changing element 3.
  • the emitted laser light passing through the polarizer is polarized light and is irradiated on the object.
  • the object is reflected and received by the radar.
  • the polarization direction and the polarization direction of the emitted light are perpendicular to each other, reflected by the mirror to the detector, and detected.
  • the stray light in the environment is generally unpolarized light. Since the mirror only has a high reflectivity for light polarized in a specific direction, it helps to reduce the ambient stray light detected by the detector, thereby improving the signal-to-noise ratio of the system .
  • the light source may be an edge-emitting laser
  • the detector includes an avalanche diode for receiving at least part of the returned light condensed by the transceiving element, and the received return light Light is converted into electrical signals.
  • the structure of the EEL laser includes: a first electrode 301, the first heat sink is disposed on the first surface of the laser diode chip 302 where the first electrode is located Upper; second electrode 303, the second heat sink is provided on the second surface of the laser diode chip where the second electrode is located.
  • the laser diode chip has a rectangular parallelepiped structure, the first surface and the second surface are upper and lower surfaces of the rectangular parallelepiped structure, and the exit surface of the laser diode chip refers to the rectangular parallelepiped structure The side surface at one end is shown in FIG. 9, and the exit surface of the laser diode chip is the side surface at the left end of the rectangular parallelepiped structure, in which the light emitting area 304 is disposed below the second electrode, as shown in FIG. 10.
  • the light source includes an edge exit laser, or the light source includes an edge exit laser array composed of a plurality of edge exit lasers, for example, the edge exit laser array is formed in several rows and columns, similarly, the detector corresponds to the light source Is an array of avalanche diodes, as shown in FIGS. 14 and 15, for example, a plurality of rows and columns of avalanche diode arrays are formed.
  • Each laser has a one-to-one correspondence with each detector, and each detector is used to receive the reflected light from the beam emitted by the laser corresponding to it.
  • the photosensitive surface of the APD is optimized to match the shape of the light spot of the return light, and the received ambient light is reduced on the premise that the return light is received by most, Thereby, the signal-to-noise ratio of the distance measuring device is provided, and the range of the system is improved.
  • the photosensitive surface of the APD is optimally designed as an ellipse or an ellipse-like shape.
  • the photosensitive surface of the APD is elliptical, as shown in FIG. 11, wherein the elliptical edge of the ellipse can be flexibly adjusted according to the elliptical flatness of the light pulse emitted by the light source, as long as the shape of the light pulse emitted by the light source and the APD
  • the photosensitive surface of the can be similar.
  • the photosensitive surface of the APD may also have other shapes, such as a rectangle-like or ellipse-like, rectangular-like or ellipse-like four rounded corners of the rectangle, as shown in FIG. 12, relative to the sharp corner Smoother.
  • the shape of the photosensitive surface of the avalanche diode matches the shape of the light spot of the return light, for example, as shown in FIG. 13, the size of the photosensitive surface 401 of the avalanche diode is larger than the size of the light spot of the return light 402, The difference between the two sizes is equal to or greater than the assembly error, as shown by the arrow, to ensure that the light spot of the returned light falls on the photosensitive surface (photosensitive surface) of the APD. In the actual installation and commissioning process, it is sufficient to reserve assembly errors between the avalanche diode and the EEL.
  • the photosensitive surface of the APD can be better matched with the return light spot, reduce the ambient light noise and electrical noise, optimize the system signal-to-noise ratio characteristics, and optimize the system ranging performance.
  • Using a smaller APD can get better system performance, and also helps to reduce the cost of APD devices.
  • the present invention provides a distance measuring device in which the lidar coaxial transceiver mirror structure is used in the distance measuring device, and the pulse laser TOF principle/frequency shift measurement/phase shift measurement is used in conjunction with the beam scanning system. Distance detection field.
  • the transceiver system in the distance measuring device of the present invention has the advantages of stronger received signal, large system tolerance, simple assembly and low cost.
  • the selected materials are easily available and the processing scheme is mature. It can be fully applied in batch engineering and is particularly suitable for certain large-diameter transceiver systems.

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Abstract

一种距离探测装置，包括：光源（1），用于发射光脉冲（2）；收发元件（4），用于准直光源（1）发射的光脉冲（2），且会聚光脉冲（2）经探测物反射的回光（5）的至少部分；探测器（6），与光源（1）放置于收发元件（4）的同一侧，用于接收收发元件（4）所会聚的回光（5）的至少部分，以及将所接收的回光（5）转换为电信号，电信号用于测量探测物与距离探测装置的距离；及光路改变元件（3），与光源（1）和探测器（6）放置于收发元件（4）的同一侧，用于将光脉冲（2）的出射光路和探测器（6）的接收光路合并；其中，光路改变元件（3）包括第一区域，第一区域用于将来自光源（1）的光脉冲（2）的部分透射或者反射至收发元件（4），第一区域对光脉冲（2）的接收立体角为探测器（6）对回光（5）的接收立体角的20％-40％。

Description

一种测距装置 技术领域
本发明涉及激光雷达技术领域，尤其涉及一种测距装置。
背景技术
激光雷达是以发射激光束探测目标的位置、速度等特征量的雷达系统。激光雷达的光敏传感器可以将获取到的光脉冲信号转变为电信号，基于比较器获取该电信号对应的时间信息，从而得到激光雷达与目标物之间的距离信息。
目前的雷达测距或探测系统，一般采用相干探测或直接信号探测：相干探测一般利用激光偏振特性，利用出射光和回光相干涉探测，该方案要保证回光偏振特性，需要较多的偏振单元，光源及信号需要调制和解调等，成本高昂，且适用于微弱信号远距离探测；直接探测多采用收发轴分离的系统结构，该方案需要较多的镜片结构。在测距装置中测距方式多采用三角法，该方法镜片多，光学成本高，且比较适合近距离高精度探测(～um级)；对于收发同轴的结构，多采用相位法或脉冲法。
在测距装置中，光源一般选用边缘出射激光器(EEL)，选用雪崩二极管(APD)作为接收元件，其中，EEL和APD均作为关键器件实现激光束的产生和探测。APD一般是圆形或方形，而采用EEL激光器，回波光斑是椭圆、近似矩形，APD圆形感光面与回波光斑难以较好的匹配，造成信噪比低，测距量程降低。
因此，目前测距装置存在上述各种急需解决的问题。
发明内容
本发明第一方面提供了一种距离探测装置，其包括：
光源，用于发射光脉冲；
收发元件，用于准直所述光源发射的光脉冲，且会聚所述光脉冲经探测物反射的回光的至少部分；
探测器，与所述光源放置于所述收发元件的同一侧，用于接收所述收发元 件所会聚的回光的至少部分，以及将所接收的回光转换为电信号，所述电信号用于测量所述探测物与所述距离探测装置的距离；及
光路改变元件，与所述光源和所述探测器放置于所述收发元件的同一侧，用于将所述光脉冲的出射光路和所述探测器的接收光路合并；
其中，所述光路改变元件包括第一区域，所述第一区域用于将来自所述光源的光脉冲的部分透射或者反射至所述收发元件，所述第一区域对所述光脉冲的接收立体角为所述探测器对所述回光的接收立体角的20％-40％。
可选地，所述收发元件的数值孔径为0.15-0.5。
可选地，所述第一区域用于将来自所述光源的光脉冲的部分透射至所述收发元件，所述光路改变元件还包括第二区域，所述第二区域用于将所述收发元件所会聚的回光的部分反射至所述探测器；
或者，
所述第一区域用于将来自所述光源的光脉冲的部分反射至所述收发元件，所述光路改变元件还包括第二区域，所述第二区域用于将所述收发元件所会聚的回光的部分透射至所述探测器。
可选地，所述第一区域在与所述光脉冲的光轴垂直的平面上的投影面积为所述第二区域在该平面上的投影面积的20％-40％。
可选地，所述光路改变元件用于将所述光源发射的光脉冲的总能量中的60％-85％能量的光脉冲出射至所述收发元件。
可选地，所述探测器接收的回光的能量占所述所述光路改变元件的接收的回光能量的60％以上。
可选地，所述第一区域对所述光脉冲的接收立体角近似为所述第一区域在与所述光脉冲的光轴垂直的平面上的投影面积与所述平面与光源之间距离平方的比；
和/或，
所述探测器对回光的有效接收立体角小于或等于所述探测器对所述回光的接收立体角与所述第一区域对所述光脉冲的接收立体角的差值。
可选地，所述第一区域在与所述光脉冲的光轴垂直的平面上的投影的形状 与所述光脉冲在该平面上形成的光斑的形状匹配；
或者，
所述第一区域的形状与所述光源的发光面的形状匹配。
可选地，所述第一区域在与所述光脉冲的光轴垂直的平面上的投影的形状与所述光脉冲在该平面上形成的光斑的形状为匹配的圆形、椭圆形、梯形或矩形；
或者，
所述第一区域的形状和所述光斑的形状为匹配的圆形、椭圆形、梯形或矩形。
可选地，所述光源包括激光二极管，所述第一区域在所述激光二极管的快轴方向上的口径大于在所述激光二极管的慢轴方向上的口径。
可选地，其特征在于，所述第一区域包括位于光轴两侧的第一端和第二端，其中，所述第一端相比第二端靠近光源，并且在平行于所述光脉冲的光轴的方向上第二端的口径大于第一端的口径。
可选地，所述第一区域为梯形。
可选地，所述第一区域在与所述光脉冲的光轴垂直的平面上的投影面积小于所述光脉冲在该平面上形成的光斑的面积。
可选地，所述收发元件包括透镜组、非球面透镜和梯度折射率透镜中的至少一种。
可选地，所述光路改变元件设置于光源发射的光脉冲的一侧，和/或所述光路改变元件位于所述收发元件焦距以内。
可选地，所述光路改变元件的表面为平面或曲面。
可选地，所述探测器和所述光源中的一者放置于所述收发元件的焦面上，另一者放置于所述收发元件的光轴的一侧。
可选地，所述光路改变元件放置于所述收发元件和所述光源之间，允许所述光源发射的光脉冲透射，且允许穿过所述收发元件的所述回光反射至所述探测器；
或者所述光路改变元件放置于所述收发元件和所述光源的同一侧，允许所 述光源发射的光脉冲反射，且允许穿过所述收发元件的所述回光出射至所述探测器。
可选地，所述第一区域的中心与所述光源的发射光脉冲的光轴重合。
可选地，所述第一区域的中心偏离所述收发元件的光轴。
可选地，所述光路改变元件具体为设置在所述第一区域的反射面。
可选地，所述第一区域设置为透射开孔，或者，所述第一区域包括透光基材；
所述第二区域设置为反射面。
可选地，所述第一区域包括透光基材；其中，
所述第一区域面向和/或背向所述光源的表面上镀有增透膜；或者，
所述光路改变元件面向所述光源的表面上镀有增透膜；或者，
所述第一区域上设置有偏振膜，所述偏振膜的偏振方向与所述发射光脉冲的偏振方向相同。
可选地，所述第一区域和所述第二区域均包括镀有偏振膜的透光基材，所述偏振膜的偏振方向与所述发射光脉冲的偏振方向相同，并且在所述收发元件的一侧设置非互易偏振旋转器件，使得所述光脉冲的偏振方向与经过所述非互易偏振旋转器件的回光的偏振方向垂直。
可选地，所述非互易偏振旋转器件包括法拉第旋镜。
可选地，所述非互易偏振旋转器件用于将准直后所述光源发射的光脉冲的偏振方向与所述发射光脉冲的偏振方向呈45度。
可选地，所述光路改变元件放置于所述收发元件和所述光源的同一侧，并且所述收发元件的有效口径大于所述光路改变元件的有效口径。
可选地，所述光源的中轴线垂直于所述探测器的中轴线。
可选地，所述距离探测装置包括多个所述光源、与多个所述光源对应的多个所述探测器，及与多个所述光源和所述探测器对应的多个光路改变元件。
可选地，所述光源包括至少一个边缘出射激光器，所述探测器包括至少一个雪崩二极管，用于接收所述收发元件所会聚的回光的至少部分，以及将所接收的回光转换为电信号。
可选地，所述雪崩二极管的光敏面的形状与所述回光的光斑的形状相匹配。
可选地，所述雪崩二极管的光敏面的尺寸大于所述回光的光斑的尺寸，两者尺寸的差值等于或大于组装误差。
可选地，所述雪崩二极管的光敏面的形状为椭圆或类椭圆形。
可选地，所述类椭圆形为顶角圆化的矩形。
可选地，所述光源包括多个边缘出射激光器规则排列形成的边缘出射激光器线阵列，所述探测器包括多个雪崩二极管规则排列形成的雪崩二极管线阵列；
所述多个边缘出射激光器线阵列与所述雪崩二极管线阵列一一对应。
可选地，所述光源包括多个边缘出射激光器规则排列形成的边缘出射激光器面阵列，所述探测器包括多个雪崩二极管规则排列形成的雪崩二极管面阵列；
所述边缘出射激光器面阵列与所述雪崩二极管面阵列一一对应。
本发明通过提供了一种测距装置，在所述测距装置中采用激光雷达同轴收发镜结构，利用脉冲激光TOF原理/频移测量/相移测量，配合光束扫描系统，应用于雷达及距离探测领域。和相干探测相比，具有结构简单、成本低廉、性价比高的优势；和直接探测的三角法相比，光学元件少、收发同轴、装调简单；和直接探测的相位法相比，不需要调制光源、测距范围大、响应速度快，更适合做扫描探测。
附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例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，下面描述中的附图仅仅是本发明的一些实施例，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是本发明一实施例提供的测距装置中激光雷达收发同轴系统的示意图；
图2是本发明实施例提供的测距装置中边缘发射激光二极管发射光的示意图；
图3A-3E是本发明实施例提供的测距装置中光路改变元件的结构示意图；
图4是本发明另一实施例提供的测距装置中激光雷达收发同轴系统的示 意图；
图5是本发明又一实施例提供的测距装置中激光雷达收发同轴系统的示意图；
图6是本发明又一实施例提供的测距装置中激光雷达收发同轴系统的示意图；
图7是本发明又一实施例提供的测距装置中激光雷达收发同轴系统的示意图；
图8是本发明实施例提供的测距装置采用同轴光路的一种实施例的示意图；
图9示出本发明实施例提供的测距装置中EEL的结构示意图；
图10示出图9中EEL沿B-B方向的剖视图；
图11示出本发明一实施例提供的测距装置中APD光敏面的形状示意图；
图12示出本发明另一实施例提供的测距装置中APD光敏面的形状示意图；
图13示出本发明另一实施例提供的测距装置中APD光敏面与回光光斑之间关系的示意图；
图14示出本发明一实施例提供的测距装置中APD阵列光敏面的形状示意图；
图15示出本发明另一实施例提供的测距装置中APD阵列光敏面的形状示意图。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅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。
目前的雷达测距或探测系统，一般采用相干探测或直接信号探测，但各自都存在各种弊端，例如需要较多的偏振单元，光源及信号需要调制和解调等，成本高昂，且适用于微弱信号远距离探测；或需要较多的镜片结构；或光学成本高等。
在测距装置中，光源一般选用边缘出射激光器(EEL)，选用雪崩二极管(APD)作为接收元件，因其发光区扁平、狭长，例如75um×10um，或者150um×10um等。经过光学系统准直后，其光斑尺寸也是长方形的。与之对应的，激光在物体上反射被激光雷达接收后，在焦平面上形成的光斑也是长方形的。
为了使用APD对回波信号的探测，往往需要APD的光敏面尺寸大于光斑尺寸，但也并非也大越好：当APD感光面尺寸增大时，比光敏面尺寸大的区域会接收到更多的杂散光等，形成噪声，当光敏面尺寸增大时，表面漏电流等引起的电噪声也会增大。噪声的增大会恶化系统的噪声特性，降低系统测距特性；当APD感光面尺寸增大时，实现成本增大。APD的光敏面一般设置为圆形，或方形，无法通过简单的调整圆形的直径使得感光面与回波光斑较好的匹配。
为了解决上述各种问题中的至少一种问题，本发明提供了一种测距装置，下面首先接合附图8对本发明实施例中的所述测距装置的整体结构进行说明，然后在对该测距装置中的收发同轴系统进行详细的说明。
首先参照图8，图8示出了本发明的测距装置采用同轴光路的一种实施例的示意图。测距装置200包括测距模块210，测距模块210包括光源203(可以包括发射电路)、准直元件204、探测器205(可以包括接收电路、采样电路和运算电路)和光路改变元件206。测距模块210用于发射光束，且接收回光，将回光转换为电信号。其中，光源203可以用于发射光脉冲序列。在一个实施例中，光源203可以发射激光脉冲序列。可选的，光源203发射出的激光束为波长在可见光范围之外的窄带宽光束。准直元件204设置于光源的出射光路上，用于准直从光源203发出的光束，将光源203发出的光束准直为平行光出射至扫描模块。准直元件还用于会聚经探测物反射的回光的至少一部分。该准直元件204可以是准直透镜或者是其他能够准直光束的元件。
在图8所示实施例中，通过光路改变元件206来将测距装置内的发射光路和接收光路在准直元件204之前合并，使得发射光路和接收光路可以共用同一个准直元件，使得光路更加紧凑。在其他的一些实现方式中，也可以是光源203和探测器205分别使用各自的准直元件，将光路改变元件206设置在准直 元件之后的光路上。
在图8所示实施例中，由于光源203出射的光束的光束孔径较小，测距装置所接收到的回光的光束孔径较大，所以光路改变元件可以采用小面积的反射镜来将发射光路和接收光路合并。在其他的一些实现方式中，光路改变元件也可以采用带通孔的反射镜，其中该通孔用于透射光源203的出射光，反射镜用于将回光反射至探测器205。这样可以减小采用小反射镜的情况中小反射镜的支架会对回光的遮挡。
在图8所示实施例中，光路改变元件偏离了准直元件204的光轴。在其他的一些实现方式中，光路改变元件也可以位于准直元件204的光轴上。
测距装置200还包括扫描模块202。扫描模块202放置于测距模块210的出射光路上，扫描模块202用于改变经准直元件204出射的准直光束219的传输方向并投射至外界环境，并将回光投射至准直元件204。回光经准直元件204汇聚到探测器205上。
在一个实施例中，扫描模块202可以包括至少一个光学元件，用于改变光束的传播路径，其中，该光学元件可以通过对光束进行反射、折射、衍射等等方式来改变光束传播路径。例如，扫描模块202包括透镜、反射镜、棱镜、振镜、光栅、液晶、光学相控阵(Optical Phased Array)或上述光学元件的任意组合。一个示例中，至少部分光学元件是运动的，例如通过驱动模块来驱动该至少部分光学元件进行运动，该运动的光学元件可以在不同时刻将光束反射、折射或衍射至不同的方向。在一些实施例中，扫描模块202的多个光学元件可以绕共同的轴209旋转或振动，每个旋转或振动的光学元件用于不断改变入射光束的传播方向。在一个实施例中，扫描模块202的多个光学元件可以以不同的转速旋转，或以不同的速度振动。在另一个实施例中，扫描模块202的至少部分光学元件可以以基本相同的转速旋转。在一些实施例中，扫描模块的多个光学元件也可以是绕不同的轴旋转。在一些实施例中，扫描模块的多个光学元件也可以是以相同的方向旋转，或以不同的方向旋转；或者沿相同的方向振动，或者沿不同的方向振动，在此不作限制。
在一个实施例中，扫描模块202包括第一光学元件214和与第一光学元件 214连接的驱动器216，驱动器216用于驱动第一光学元件214绕转动轴209转动，使第一光学元件214改变准直光束219的方向。第一光学元件214将准直光束219投射至不同的方向。在一个实施例中，准直光束219经第一光学元件改变后的方向与转动轴209的夹角随着第一光学元件214的转动而变化。在一个实施例中，第一光学元件214包括相对的非平行的一对表面，准直光束219穿过该对表面。在一个实施例中，第一光学元件214包括厚度沿至少一个径向变化的棱镜。在一个实施例中，第一光学元件214包括楔角棱镜，对准直光束219进行折射。
在一个实施例中，扫描模块202还包括第二光学元件215，第二光学元件215绕转动轴209转动，第二光学元件215的转动速度与第一光学元件214的转动速度不同。第二光学元件215用于改变第一光学元件214投射的光束的方向。在一个实施例中，第二光学元件115与另一驱动器217连接，驱动器217驱动第二光学元件215转动。第一光学元件214和第二光学元件215可以由相同或不同的驱动器驱动，使第一光学元件214和第二光学元件215的转速和/或转向不同，从而将准直光束219投射至外界空间不同的方向，可以扫描较大的空间范围。在一个实施例中，控制器218控制驱动器216和217，分别驱动第一光学元件214和第二光学元件215。第一光学元件214和第二光学元件215的转速可以根据实际应用中预期扫描的区域和样式确定。驱动器216和217可以包括电机或其他驱动器。
在一个实施例中，第二光学元件215包括相对的非平行的一对表面，光束穿过该对表面。在一个实施例中，第二光学元件215包括厚度沿至少一个径向变化的棱镜。在一个实施例中，第二光学元件215包括楔角棱镜。
一个实施例中，扫描模块202还包括第三光学元件(图未示)和用于驱动第三光学元件运动的驱动器。可选地，该第三光学元件包括相对的非平行的一对表面，光束穿过该对表面。在一个实施例中，第三光学元件包括厚度沿至少一个径向变化的棱镜。在一个实施例中，第三光学元件包括楔角棱镜。第一、第二和第三光学元件中的至少两个光学元件以不同的转速和/或转向转动。
扫描模块202中的各光学元件旋转可以将光投射至不同的方向，例如投射 的光211的方向和方向213，如此对测距装置200周围的空间进行扫描。当扫描模块202投射出的光211打到探测物201时，一部分光被探测物201沿与投射的光211相反的方向反射至测距装置200。探测物201反射的回光212经过扫描模块202后入射至准直元件204。
探测器205与光源203放置于准直元件204的同一侧，探测器205用于将穿过准直元件204的至少部分回光转换为电信号。
一个实施例中，各光学元件上镀有增透膜。可选的，增透膜的厚度与光源203发射出的光束的波长相等或接近，能够增加透射光束的强度。
一个实施例中，测距装置中位于光束传播路径上的一个元件表面上镀有滤光层，或者在光束传播路径上设置有滤光器，用于至少透射光源所出射的光束所在波段，反射其他波段，以减少环境光给接收器带来的噪音。
在一些实施例中，光源203可以包括激光二极管，通过激光二极管发射纳秒级别的激光脉冲。进一步地，可以确定激光脉冲接收时间，例如，通过探测电信号脉冲的上升沿时间和/或下降沿时间确定激光脉冲接收时间。如此，测距装置200可以利用脉冲接收时间信息和脉冲发出时间信息计算TOF，从而确定探测物201到测距装置200的距离。
测距装置200探测到的距离和方位可以用于遥感、避障、测绘、建模、导航等。在一种实施方式中，本发明实施方式的测距装置可应用于移动平台，测距装置可安装在移动平台的平台本体。具有测距装置的移动平台可对外部环境进行测量，例如，测量移动平台与障碍物的距离用于避障等用途，和对外部环境进行二维或三维的测绘。在某些实施方式中，移动平台包括无人飞行器、汽车、遥控车、机器人、相机中的至少一种。当测距装置应用于无人飞行器时，平台本体为无人飞行器的机身。当测距装置应用于汽车时，平台本体为汽车的车身。该汽车可以是自动驾驶汽车或者半自动驾驶汽车，在此不做限制。当测距装置应用于遥控车时，平台本体为遥控车的车身。当测距装置应用于机器人时，平台本体为机器人。当测距装置应用于相机时，平台本体为相机本身。
上述实施例对所述测距装置的整体结构以及工作原理进行了解释和说明，下面结合附图对本发明实施例的测距装置中由光源至探测器的同轴光路进行 详细的说明。
首先参照附图1，在本发明的另一实施例中，所述测距装置包括光源1，用于发射光脉冲；
收发元件4，用于准直所述光源发射的光脉冲2，且会聚所述光脉冲经探测物反射的回光的至少部分；
探测器6，与所述光源放置于所述收发元件的同一侧，用于接收所述收发元件所会聚的回光5的至少部分，以及将所接收的回光转换为电信号，所述电信号用于测量所述探测物与所述距离探测装置的距离；及
光路改变元件3，与所述光源和所述探测器放置于所述收发元件的同一侧，用于将所述光脉冲的出射光路和所述探测器的接收光路合并；
其中，所述光路改变元件包括第一区域，所述第一区域用于将来自所述光源的光脉冲的部分透射或者反射至所述收发元件，所述第一区域对所述光脉冲的接收立体角为所述探测器对所述回光的接收立体角的20％-40％。
需要说明的是，其中光源以及探测器均可以参照本发明上述实施例中的相关介绍，下面重点对收发元件4和光路改变元件3进行详尽的说明。
在本发明的该实施例中，所述光路改变元件3即可以选用的表面为平面的光学元件，如图1所示，也可以选用表面为曲面的光学元件，如图6和图7所示，并不局限于某一种。
例如，所述光路改变元件3选用表面为凹面的反射镜，可以使探测器接收焦距变短，整个系统在接收方向上会更加紧凑，并且凹面反射镜的应用，使得接收和发射的透镜系统不同，接收系统的FOV更大，接收光信号更强。
所述光路改变元件3不管选用平面或曲面的光学元件均要求所述第一区域对所述光脉冲的接收立体角为所述探测器对所述回光的接收立体角的20％-40％。该设置不仅考虑了光路改变元件3对发射的光脉冲透射或者反射的有效面积，还考虑了光路改变元件3对回光进行反射或透射的面积，综合考虑两者之间的比例，通过该设置可以使在所述光路改变元件3上被透射或者反射至所述收发元件的光脉冲和经探测物反射的回光经光路改变元件3后被探测器接收的光脉冲之间的信号比例最佳，以使所述探测装置实现最长的探测距离。
其中，立体角是指光脉冲以椎体的顶点为球心做球面，该椎体在球表面截取的面积与球半径平方之比，单位为球面度。当角度不大时，立体角可以近似为椎体平面面积与椎体的边长平方之比。在该实施中，所述第一区域对所述光脉冲的接收立体角为所述第一区域在与所述光脉冲的光轴垂直的平面上的投影面积与所述平面与光源之间距离平方的比。在没有特殊说明的情况下，下文提及的立体角均参照该解释和说明。
其中，立体角还与收发元件的数值孔径有关，在该实施例中，所述收发元件的数值孔径为0.15-0.5。
其中，所述光路改变元件3还可以包括第二区域，所述第一区域用于将来自所述光源的光脉冲的部分透射至所述收发元件，所述第二区域用于将所述收发元件所会聚的回光的部分反射至所述探测器，如图1所示；
或者，
所述光路改变元件3还可以包括第二区域，所述第一区域用于将来自所述光源的光脉冲的部分反射至所述收发元件，所述第二区域用于将所述收发元件所会聚的回光的部分透射至所述探测器。
可选地，所述第一区域的中心与所述光源的发射光脉冲的光轴重合，以保证足够多的光脉冲能被所述光路改变元件3透射或反射。
可选地，所述第一区域的中心偏离所述收发元件的光轴，例如在本发明的一实施例中所述光路改变元件3倾斜设置，所述光路改变元件3与所述收发元件的光轴之间的夹角大致呈45°。
在本发明的一具体实施方式中，所述光路改变元件3包括第一区域和第二区域，其中所述第一区域用于将来自所述光源的光脉冲的部分透射至所述收发元件，所述第二区域用于将所述收发元件所会聚的回光的部分反射至所述探测器，具体地，光源1发出的光脉冲2经过光路改变元件3到达收发元件(例如准直接收透镜)4，经过准直后打在探测物上；探测物反射的回光5经过准直接收透镜接收，通过半反半透镜到达探测器6，接收信号再经过一些放大、滤波、算法处理，完成对目标距离及角度的探测。
在该实施例中，光源1和探测器6分别位于收发元件(例如准直接收透镜) 的后向焦点上，准直接收透镜为专用胶合透镜组或非球面透镜或梯度折射率透镜，既充当激光发射的准直镜，又作为回光的接收镜，具像差小、成本低廉，易加工的优点。
其中，光路改变元件3位于准直接收透镜的后向焦距内，对发射激光具有透射效果，对回光有反射作用，通过利用透镜的不同立体角，实现收发信号方向的分离。
具体地，所述收发元件4可以包括透镜组、非球面透镜和梯度折射率透镜中的至少一种。透镜组可以包括若干凹透镜以及若干凸透镜的相互组合，其数目以及组合方式并不局限于某一种，可以根据实际需要进行设置。在该实施例中，所述收发元件4选用一凸透镜。
其中，该光路改变元件3的具体形状不限制于某一种，只要能够对发射激光实现透射，对接收信号实现反射即可应用于该实施例。
可选地，所述第一区域在与所述光脉冲的光轴垂直的平面上的投影的形状与所述光脉冲在该平面上形成的光斑的形状匹配，以使光脉冲尽可能多的投射出第一区域，以增加测量量程。例如所述第一区域在与所述光脉冲的光轴垂直的平面上的投影的形状与所述光脉冲在该平面上形成的光斑的形状为匹配的圆形、椭圆形、梯形或矩形，但并不局限于上述形状，还可以选用其他实际可行的形状。
一个示例中，所述第一区域在与所述光脉冲的光轴垂直的平面上的投影面积小于所述光脉冲在该平面上形成的光斑的面积，以使所述第一区域被有效充分的利用。
可选地，所述第一区域的形状与所述光源的发光面的形状匹配，所述光源的发光面的形状与光脉冲在垂直于光轴的平面上形成的光斑的形状是相同的。在该实施例中，该光路改变元件3的透射窗口，即对光源1或者探测器6张开的角度孔径、形状与选用的光源光斑匹配，如光源为长条形光斑，该光路改变元件3等效的透射窗为长短方向对应的长条形；如光源为圆形光斑，该光路改变元件3等效的透射窗也匹配为圆形；如光源为椭圆形光斑，该光路改变元件3等效的透射窗也匹配为长短方向对应的椭圆形；如光源为梯形光斑，该光路 改变元件3等效的透射窗也匹配为长短方向对应的梯形。
在该实施例中，所述光源选用边缘发射激光二极管，其辐射光场在快轴和慢轴方向的发散角是不同的，如图2所示，其中A-A1为快轴方向，B-B1为慢轴方向，在快慢轴方向，发散角的半高宽分别为15～30°和6～15°，其辐射光斑是椭圆形的，因此，反射镜开孔设置成与之匹配的椭圆形或者矩形，能获得较好的性能。相对应地，所述第一区域在所述激光二极管的快轴方向上的口径大于在所述激光二极管的慢轴方向上的口径，以使所述第一区域与所述边缘发射激光二极管的光斑相匹配。
一个示例中，所述第一区域包括位于光轴两侧的下端和上端，其中，所述下端相比上端靠近光源，如图1所示，并且在平行于所述光脉冲的光轴的方向上上端的口径大于下端的口径。例如，该实施例中光路改变元件3的第一区域(透射窗口)实际面积、形状与倾斜角度有关，具体为光源发射的沿光轴方向的有效立体角与倾斜的光路改变元件3重叠截取决定；因为倾斜放置，反射镜等效透射窗口形状类似梯形，上部宽，底部窄；并且倾斜角度越大，梯形上下宽窄比越大。
一个示例中，所述第一区域在与所述光脉冲的光轴垂直的平面上的投影面积为所述第二区域在该平面上的投影面积的20％-40％。所述光路改变元件用于将所述光源发射的光脉冲的总能量中的60％-85％能量的光脉冲出射至所述收发元件。所述探测器接收的回光的能量占所述所述光路改变元件的接收的回光能量的60％以上。在该实施例中考虑经过透镜接收信号被透射窗口损失的接收信号比例，为了保证光路改变元件3透射和反射的有效面积比例，同时考虑激光光源强度分布和实际发射比例，通过对所述透射窗口大小进行合理的设置，使出射激光能量适中，出射激光能量和目标反射信号均达到一定的强度和能量，从而增加测量量程，以避免该光路改变元件3等效的第一区域(透射窗口)实际面积过大，出射激光能量越高，但是接收信号因为等效的透射窗口的损失能量反而会降低，能量从中间损失的问题。
其中，该光路改变元件3置于准直接收透镜的后向焦距内，越接近透镜越好(加工公差及装配误差敏感度会降低)。
其中，在本发明的一实施例中，所述探测器放置于所述收发元件的焦面上，光源放置于所述收发元件的光轴的一侧，或者所述光源放置于所述收发元件的焦面上，探测器放置于所述收发元件的光轴的一侧。
进一步，所述光路改变元件放置于所述收发元件和所述光源之间，如图1、图4和图7所示，允许所述光源发射的光脉冲透射，且允许穿过所述收发元件的所述回光反射至所述探测器，在该设置方式中，并且所述收发元件的有效口径小于所述光路改变元件的有效口径。
或者如图5和6所示，所述光路改变元件放置于所述收发元件和所述光源的同一侧，允许所述光源发射的光脉冲反射，且允许穿过所述收发元件的所述回光出射至所述探测器，并且所述收发元件的有效口径大于所述光路改变元件的有效口径。其基本结构和原理与图1、图4和图7所示示例相同，只是对探测器和光源的位置进行了换向，并且光路改变元件3的体积变小，对出射的光脉冲反射，对回光的信号透过，基本特点不变。
如上所述，在本发明的该实施例中，所述光路改变元件3即可以选用的表面为平面的光学元件，如图1所示，也可以选用表面为曲面的光学元件，如图6和图7所示。
通过上述实施例对同轴光路进行了说明，下面对所述光路改变元件3的具体结构以及选用其他类型的光学元件的实施例进行阐述，需要说明的是，只要下述实施方式与上述实施例不相互矛盾，下述实施方式均可以应用于上述实施例。
一个示例中，光路改变元件3包括第一区域和第二区域，下面以第一区域为透射窗口，第二区域为反射窗口为例进行说明。其中，所述第一区域包括透光基材；所述第一区域面向和/或背向所述光源的表面上镀有增透膜；或者，所述光路改变元件面向所述光源的表面上镀有增透膜；或者，所述第一区域上设置有偏振膜，所述偏振膜的偏振方向与所述发射光脉冲的偏振方向相同。具体地，上述方案的实现方式具体如下：
第一，光路改变元件3设置为开孔反射镜：
如图1和图3B所示，光路改变元件3中间开孔，孔的大小由反射镜倾斜 角度与光源辐射光场的空间分布、透镜有效数值孔径决定，如图3A所示，其中30为光轴、31为反射镜非反射面、32为反色镜的反射面、33为中间开孔区域、301为与光轴垂直的平面，图3A为光路改变元件3在301面的投影，开孔区域33的投影形状与所用光源发光面形状匹配：在两个方向上的尺寸与光源辐射光场的强度特征相关。
在该示例中，光路改变元件与光轴倾斜放置，发射激光通过开孔区域33中间开孔出射，回光的波信号通过反射面32反射到探测器被接收，回光实际被探测器接收到65～75％左右。
可选地，光路改变元件的反射面还可以镀增反膜，可以是介质膜或金属膜，反射率大于90％，波段范围880nm～950nm；该光路改变元件非反射面可做降低反射率处理(消除杂散光导致的T0影响)，对应面积涂对应波段吸收的油墨、黑漆、胶水或其他具有降低反射率的涂层，也可做增透镀膜处理。
第二、光路改变元件3设置为增透反射镜：该示例可降低开孔面及非反射面导致的杂散光带来的T0的影响，而且镜片加工更简单；
1、如图3C所示，其中，图3C为光路改变元件在301面的投影，光路改变元件中间第一区域33镀增透膜，不开孔，透过率大于80％(例如大于98％)，在反射面32镀高反膜，反射率大于80％(例如大于90％)，波段范围880nm～950nm；镀膜区域33的形状与所用光源发散情况相匹配。
在该实例中，光路改变元件3与光轴倾斜放置，发射激光通过33中间镀膜出射，回光通过反射面32反射到探测器被接收，回光实际被探测器接收到60～80％左右。
2、作为该示例的一种替代性实施方式，光路改变元件3不再开孔，光路改变元件的非反射面31整面镀增透膜，图3D为光路改变元件的反射面，反射面32镀高反膜，第一区域33镀增透膜，膜反射率及波段要求不变；在该示例中，光路改变元件3与光轴倾斜放置，发射激光通过33中间镀膜出射，回光通过反射面32反射到探测器被接收。
3、作为该示例的另外一种替代性实施方式，光路改变元件3不再开孔，非反射面31整面不镀膜，图3D为光路改变元件非反射面，反射面32镀高反 膜，第一区域33镀增透膜，膜反射率及波段要求不变；在该示例中，此示例，光路改变元件3与光轴倾斜放置，发射激光可选用偏振度大于95％的偏振光源(一般半导体激光器均为线偏振光)，通过菲涅尔反射定律，让发射激光的偏振方向与纸面平行(P光)，此时96％以上的发射激光将通过33中间镀膜出射，回光通过反射面32反射到探测器被接收。
4、作为该示例的再一种替代性实施方式，光路改变元件上不再开孔，非反射面31整面不镀膜，反射面32镀高反膜，第一区域33不镀膜；图3D为光路改变元件的发射面，其中，高反膜的波段和反射率要求不变。
在该示例中，还可以利用菲涅耳反射原理减小非反射面31对出射激光的反射。具体地，光路改变元件与光轴倾斜放置，发射激光可选用偏振度大于95％的偏振光源(一般半导体激光器均为线偏振光)，且发射激光的偏振方向为P偏振态(P光)，通过菲涅尔反射定律，减小不镀膜区域33对发射激光的反射，回光通过反射面32反射到探测器被接收。优选的，在此方案中，光路改变元件3的玻璃的材料折射率大于1.72，对应的Brewster角大于60度。
第三、光路改变元件3设置为偏振镜，通过所述设置杂散光会降低很多，而且偏振镜结构简单；
1、在本发明的一示例中，如图3E所示，光路改变元件选择为偏振镜或偏振片，偏振光透过率需＞90％，光路改变元件中间不开孔，偏振镜或偏振片的偏振方向为35(平行纸面P光)，非反射面和反射面可以不镀膜。
此示例，光路改变元件3与光轴倾斜放置，发射激光可选用偏振度大于95％的偏振光源(一般半导体激光器均为线偏振光)，发射激光的偏振方向与偏振镜偏振方向相同(P光)，此时90％以上的发射激光将通过偏振镜出射，回光通过反射面32反射到探测器被接收。回波不再是偏振光，通过偏振镜反射的信号有回光的45％以上。
2、作为该示例的另外一种替代性实施方式，光路改变元件3选择为透光材质，例如普通玻璃，中间区域33镀偏振膜(不开孔)，使得偏振方向与出射激光偏振方向相同的光透射率较高。非反射面31不镀膜，反射面32镀高反膜，膜反射率及波段要求不变；
在此示例中，光路改变元件3与光轴倾斜放置，倾斜角度需与光路改变元件的偏振角相近，发射激光可选用偏振度大于95％的偏振光源(一般半导体激光器均为线偏振光)，发射激光的偏振方向与偏振膜偏振方向35相同，此时90％以上的发射激光将通过偏振镜出射，回光通过反射面32反射到探测器被接收。因为目标特性不确定，回波不再是偏振光，有部分反射光仍然能通过区域33反射到探测器，因而可以提高探测到的回波功率。此时通过反射面32反射的回光的可控制在65％以上。
第四，光路改变元件3设置为偏振镜+非互易偏振旋转器件(法拉第旋镜或1/4片)，通过所述设置可以杂散光会降低很多，接收信号强度会增加很多，但镜片增多，成本增大，结构变复杂；
具体地，在该示例中，所述第一区域和所述第二区域均包括镀有偏振膜的透光基材，所述偏振膜的偏振方向与所述发射光脉冲的偏振方向相同，并且在所述收发元件的一侧设置非互易偏振旋转器件，使得所述光脉冲的偏振方向与经过所述非互易偏振旋转器件的回光的偏振方向垂直。
如图4所示，激光器辐射的光为线偏振光，光路改变元件选择为偏振镜或偏振片，偏振透过方向与激光器辐射光的偏振方向相同，偏振光透过率需＞80％，光路改变元件3中间不开孔；对垂直偏振方向的光具有较高的反射率，反射率大于80％。非反射面和反射面可以不镀膜；准直透镜后放置一个法拉第旋镜7，对应波长为905nm，口径不小于透镜口径。所述法拉第旋镜用于将准直后所述光源发射的光脉冲的偏振方向与所述发射光脉冲的偏振方向呈45度。在出射激光经过外部标准镜面反射的情况下，由于法拉第旋镜的作用，回波经过法拉第旋镜后的偏振方向与出射激光的偏振方向垂直，因而，会被反射镜反射到探测器上被探测。
在该示例中，发射激光可选用偏振度大于95％的偏振光源，发射激光的偏振方向与光路改变元件3的偏振透射方向相同，通过偏振片的发射激光为偏振光，照射到物体上，被物体反射，被雷达接收，经过法拉第旋镜后偏振方向与发射光的偏振方向相互垂直，被反射镜反射到探测器处，探测。环境中的杂散光一般是非偏振光，由于反射镜只对特定方向偏振的光具有较高的反射率，因 而，有助于减小探测器探测到的环境杂散光，从而提高系统的信噪比。
在本发明中提及的上述实施例中，光源均可以选用边缘出射激光器，所述探测器包括雪崩二极管，用于接收所述收发元件所会聚的回光的至少部分，以及将所接收的回光转换为电信号。
其中，EEL激光器的结构如图9和10所示，所述EEL激光器包括：第一电极301，所述第一热沉设置于所述第一电极所在的所述激光二极管芯片302的第一表面上；第二电极303，所述第二热沉设置于所述第二电极所在的所述激光二极管芯片的第二表面上。在一具体实施方式中，所述激光二极管芯片呈长方体结构，所述第一表面和第二表面为所述长方体结构的上表面和下面，所述激光二极管芯片的出射面是指所述长方体结构一端的侧面，如图9所示，所述激光二极管芯片的出射面为长方体结构左端的侧面，其中发光区域304设置于所述第二电极的下方，如图10所示。
其中，所述光源包括一个边缘出射激光器，或者光源包括多个边缘出射激光器组成的边缘出射激光器阵列，例如形成若干行，若干列的边缘出射激光器阵列，类似的，所述探测器与光源相对应，为雪崩二极管的阵列，如图14和图15所示，例如形成若干行，若干列的雪崩二极管阵列。各激光器与各探测器一一对应，每个探测器用于接收与其对应的激光器出射的光束经反射回的回光。
在本发明的实施例中，对APD的光敏面进行了优化设计，使之与回光的光斑形状相匹配，在保证回光被绝大部分接收的前提下，减小接收到的环境光，从而提供测距装置的信噪比，提高系统的量程。在采用EEL作为光源的测距装置中，APD的光敏面优化设计为椭圆形或类椭圆形。
例如所述APD的光敏面为椭圆形，如图11所示，其中椭圆形的椭圆边度可以根据光源发射的光脉冲的椭圆扁度进行灵活的调整，只要光源发射的光脉冲的形状与APD的光敏面成相似形即可。
除了椭圆形，所述APD的光敏面还可以为其他形状，例如类似矩形或类似椭圆形，类似矩形或类似椭圆形为矩形的四个顶角圆化，如图12所示，相对于尖角更加圆滑。
所述雪崩二极管的光敏面的形状与所述回光的光斑的形状相匹配，例如，如图13所示，所述雪崩二极管的光敏面401的尺寸大于所述回光402的光斑的尺寸，两者尺寸的差值等于或大于组装误差，如箭头所示，以保证回光的光斑落在APD的光敏面(感光面)内。在实际的安装和调试过程中，雪崩二极管和EEL之间预留组装误差即可。
通过对探测器中APD的优化可以使APD光敏面与回光光斑更好的匹配，减小环境光噪声和电噪声，优化系统信噪比特性，优化系统测距性能。使用较小的APD能获得更好的系统性能，还有利于降低APD器件成本。
本发明通过提供了一种测距装置，在所述测距装置中采用激光雷达同轴收发镜结构，利用脉冲激光TOF原理/频移测量/相移测量，配合光束扫描系统，应用于雷达及距离探测领域。
本发明所述测距装置中收发系统具有接收信号更强、系统容差大、装配简易及成本低廉的优势。所选材料易得、加工方案成熟，完全可以批量工程化应用，特别适合于某些大口径收发系统。
本发明实施例中所使用的技术术语仅用于说明特定实施例而并不旨在限定本发明。在本文中，单数形式“一”、“该”及“所述”用于同时包括复数形式，除非上下文中明确另行说明。进一步地，在说明书中所使用的用于“包括”和/或“包含”是指存在所述特征、整体、步骤、操作、元件和/或构件，但是并不排除存在或增加一个或多个其它特征、整体、步骤、操作、元件和/或构件。
在所附权利要求中对应结构、材料、动作以及所有装置或者步骤以及功能元件的等同形式(如果存在的话)旨在包括结合其他明确要求的元件用于执行该功能的任何结构、材料或动作。本发明的描述出于实施例和描述的目的被给出，但并不旨在是穷举的或者将被发明限制在所公开的形式。在不偏离本发明的范围和精神的情况下，多种修改和变形对于本领域的一般技术人员而言是显而易见的。本发明中所描述的实施例能够更好地揭示本发明的原理与实际应用，并使本领域的一般技术人员可了解本发明。
本发明中所描述的流程图仅仅为一个实施例，在不偏离本发明的精神的情况下对此图示或者本发明中的步骤可以有多种修改变化。比如，可以不同次序的执行这些步骤，或者可以增加、删除或者修改某些步骤。本领域的一般技术人员可以理解实现上述实施例的全部或部分流程，并依本发明权利要求所作的等同变化，仍属于发明所涵盖的范围。

Claims (36)

  1. 一种距离探测装置，其特征在于，其包括：
    光源，用于发射光脉冲；
    收发元件，用于准直所述光源发射的光脉冲，且会聚所述光脉冲经探测物反射的回光的至少部分；
    探测器，与所述光源放置于所述收发元件的同一侧，用于接收所述收发元件所会聚的回光的至少部分，以及将所接收的回光转换为电信号，所述电信号用于测量所述探测物与所述距离探测装置的距离；及
    光路改变元件，与所述光源和所述探测器放置于所述收发元件的同一侧，用于将所述光脉冲的出射光路和所述探测器的接收光路合并；
    其中，所述光路改变元件包括第一区域，所述第一区域用于将来自所述光源的光脉冲的部分透射或者反射至所述收发元件，所述第一区域对所述光脉冲的接收立体角为所述探测器对所述回光的接收立体角的20％-40％。
  2. 根据权利要求1所述的距离探测装置，其特征在于，所述收发元件的数值孔径为0.15-0.5。
  3. 根据权利要求1所述的距离探测装置，其特征在于，所述第一区域用于将来自所述光源的光脉冲的部分透射至所述收发元件，所述光路改变元件还包括第二区域，所述第二区域用于将所述收发元件所会聚的回光的部分反射至所述探测器；
    或者，
    所述第一区域用于将来自所述光源的光脉冲的部分反射至所述收发元件，所述光路改变元件还包括第二区域，所述第二区域用于将所述收发元件所会聚的回光的部分透射至所述探测器。
  4. 根据权利要求3所述的距离探测装置，其特征在于，所述第一区域在与所述光脉冲的光轴垂直的平面上的投影面积为所述第二区域在该平面上的投影面积的20％-40％。
  5. 根据权利要求1所述的距离探测装置，其特征在于，所述光路改变元 件用于将所述光源发射的光脉冲的总能量中的60％-85％能量的光脉冲出射至所述收发元件。
  6. 根据权利要求1所述的距离探测装置，其特征在于，所述探测器接收的回光的能量占所述所述光路改变元件的接收的回光能量的60％以上。
  7. 根据权利要求1所述的距离探测装置，其特征在于，所述第一区域对所述光脉冲的接收立体角为所述第一区域在与所述光脉冲的光轴垂直的平面上的投影面积与所述平面与光源之间距离平方的比；
    和/或，
    所述探测器对回光的有效接收立体角小于或等于所述探测器对所述回光的接收立体角与所述第一区域对所述光脉冲的接收立体角的差值。
  8. 根据权利要求1至7之一所述的距离探测装置，其特征在于，所述第一区域在与所述光脉冲的光轴垂直的平面上的投影的形状与所述光脉冲在该平面上形成的光斑的形状匹配；
    或者，
    所述第一区域的形状与所述光源的发光面的形状匹配。
  9. 根据权利要求8所述的距离探测装置，其特征在于，所述第一区域在与所述光脉冲的光轴垂直的平面上的投影的形状与所述光脉冲在该平面上形成的光斑的形状为匹配的圆形、椭圆形、梯形或矩形；
    或者，
    所述第一区域的形状和所述光斑的形状为匹配的圆形、椭圆形、梯形或矩形。
  10. 根据权利要求1至7之一所述的距离探测装置，其特征在于，所述光源包括激光二极管，所述第一区域在所述激光二极管的快轴方向上的口径大于在所述激光二极管的慢轴方向上的口径。
  11. 根据权利要求1至7之一或权利要求10所述的距离探测装置，其特征在于，所述第一区域包括位于光轴两侧的第一端和第二端，其中，所述第一端相比第二端靠近光源，并且在平行于所述光脉冲的光轴的方向上第二端的口径大于第一端的口径。
  12. 根据权利要求11所述的距离探测装置，其特征在于，所述第一区域为梯形。
  13. 根据权利要求1至12之一所述的距离探测装置，其特征在于，所述第一区域在与所述光脉冲的光轴垂直的平面上的投影面积小于所述光脉冲在该平面上形成的光斑的面积。
  14. 根据权利要求1所述的距离探测装置，其特征在于，所述收发元件包括透镜组、非球面透镜和梯度折射率透镜中的至少一种。
  15. 根据权利要求1所述的距离探测装置，其特征在于，所述光路改变元件设置于光源发射的光脉冲的一侧，和/或所述光路改变元件位于所述收发元件焦距以内。
  16. 根据权利要求1所述的距离探测装置，其特征在于，所述光路改变元件的表面为平面或曲面。
  17. 根据权利要求1所述的距离探测装置，其特征在于，所述探测器和所述光源中的一者放置于所述收发元件的焦面上，另一者放置于所述收发元件的光轴的一侧。
  18. 根据权利要求1至17之一所述的距离探测装置，其特征在于，所述光路改变元件放置于所述收发元件和所述光源之间，允许所述光源发射的光脉冲透射，且允许穿过所述收发元件的所述回光反射至所述探测器；
    或者所述光路改变元件放置于所述收发元件和所述光源的同一侧，允许所述光源发射的光脉冲反射，且允许穿过所述收发元件的所述回光出射至所述探测器。
  19. 根据权利要求1所述的距离探测装置，其特征在于，所述第一区域的中心与所述光源的发射光脉冲的光轴重合。
  20. 根据权利要求1所述的距离探测装置，其特征在于，所述第一区域的中心偏离所述收发元件的光轴。
  21. 根据权利要求1所述的距离探测装置，其特征在于，所述光路改变元件具体为设置在所述第一区域的反射面。
  22. 根据权利要求3所述的距离探测装置，其特征在于，所述第一区域设 置为透射开孔，或者，所述第一区域包括透光基材；
    所述第二区域设置为反射面。
  23. 根据权利要求22所述的距离探测装置，其特征在于，所述第一区域包括透光基材；其中，
    所述第一区域面向和/或背向所述光源的表面上镀有增透膜；或者，
    所述光路改变元件面向所述光源的表面上镀有增透膜；或者，
    所述第一区域上设置有偏振膜，所述偏振膜的偏振方向与所述发射光脉冲的偏振方向相同。
  24. 根据权利要求3所述的距离探测装置，其特征在于，所述第一区域和所述第二区域均包括镀有偏振膜的透光基材，所述偏振膜的偏振方向与所述发射光脉冲的偏振方向相同，并且在所述收发元件的一侧设置非互易偏振旋转器件，使得所述光脉冲的偏振方向与经过所述非互易偏振旋转器件的回光的偏振方向垂直。
  25. 根据权利要求24所述的距离探测装置，其特征在于，所述非互易偏振旋转器件包括法拉第旋镜或者1/4波片。
  26. 根据权利要求24所述的距离探测装置，其特征在于，所述非互易偏振旋转器件用于实现将所述光源发射的光脉冲的偏振方向与所接收的穿过所述非互易偏振旋转器件的至少部分回光的偏振方向呈90度。
  27. 根据权利要求18所述的距离探测装置，其特征在于，所述光路改变元件放置于所述收发元件和所述光源的同一侧，并且所述收发元件的有效口径大于所述光路改变元件的有效口径。
  28. 根据权利要求1所述的距离探测装置，其特征在于，所述光源的中轴线垂直于所述探测器的中轴线。
  29. 根据权利要求1所述的距离探测装置，其特征在于，所述距离探测装置包括多个所述光源、与多个所述光源对应的多个所述探测器，及与多个所述光源和所述探测器对应的多个光路改变元件。
  30. 根据权利要求1至29之一所述的距离探测装置，其特征在于，所述光源包括至少一个边缘出射激光器，所述探测器包括至少一个雪崩二极管，用 于接收所述收发元件所会聚的回光的至少部分，以及将所接收的回光转换为电信号。
  31. 根据权利要求30所述的距离探测装置，其特征在于，所述雪崩二极管的光敏面的形状与所述回光的光斑的形状相匹配。
  32. 根据权利要求30所述的距离探测装置，其特征在于，所述雪崩二极管的光敏面的尺寸大于所述回光的光斑的尺寸，两者尺寸的差值等于或大于组装误差。
  33. 根据权利要求30所述的距离探测装置，其特征在于，所述雪崩二极管的光敏面的形状为矩形、椭圆或类椭圆形。
  34. 根据权利要求33所述的距离探测装置，其特征在于，所述类椭圆形为顶角圆化的矩形。
  35. 根据权利要求30至34之一所述的距离探测装置，其特征在于，其特征在于，所述光源包括多个边缘出射激光器规则排列形成的边缘出射激光器线阵列，所述探测器包括多个雪崩二极管规则排列形成的雪崩二极管线阵列；
    所述多个边缘出射激光器线阵列与所述雪崩二极管线阵列一一对应。
  36. 根据权利要求35所述的距离探测装置，其特征在于，所述光源包括多个边缘出射激光器规则排列形成的边缘出射激光器面阵列，所述探测器包括多个雪崩二极管规则排列形成的雪崩二极管面阵列；
    所述边缘出射激光器面阵列与所述雪崩二极管面阵列一一对应。
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