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WO2025239064A1 - Système optique et dispositif de mesure de distance - Google Patents

Système optique et dispositif de mesure de distance

Info

Publication number
WO2025239064A1
WO2025239064A1 PCT/JP2025/013999 JP2025013999W WO2025239064A1 WO 2025239064 A1 WO2025239064 A1 WO 2025239064A1 JP 2025013999 W JP2025013999 W JP 2025013999W WO 2025239064 A1 WO2025239064 A1 WO 2025239064A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
optical system
spot
receiving
scanning direction
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.)
Pending
Application number
PCT/JP2025/013999
Other languages
English (en)
Japanese (ja)
Inventor
一能 野口
亮太 石川
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.)
Konica Minolta Inc
Original Assignee
Konica Minolta Inc
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 Konica Minolta Inc filed Critical Konica Minolta Inc
Publication of WO2025239064A1 publication Critical patent/WO2025239064A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • 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
    • 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

Definitions

  • the technology disclosed in this specification relates to optical systems and distance measuring devices.
  • Patent Document 1 discloses an optical scanning distance measuring device.
  • This distance measuring device employs a distance measuring principle known as TOF (Time of Flight).
  • the distance measuring device projects a light beam onto an object.
  • the distance measuring device receives the reflected beam returning from the object.
  • the distance measuring device calculates the distance to the object based on the time difference between the light projection and the light reception.
  • the light receiving element of this distance measuring device has multiple highly sensitive APDs (Avalanche Photodiodes) arranged in an array. When the APDs are operated in Geiger mode, the output signal of the APDs is saturated even when a single photon is incident on the APD. Therefore, the light receiving element measures the received light intensity of the reflected beam based on the number of APDs that detect the photon.
  • APDs Advanced Photodiodes
  • the dynamic range of the light receiving element in a single light projection is wide.
  • a single light projection only measures the distance to one point where the light projection beam is incident. In other words, this distance measuring device has low spatial resolution in a single light projection.
  • the technology disclosed in this specification aims to achieve both a wide dynamic range and high spatial resolution.
  • the optical system includes a light projecting optical system and a light receiving optical system.
  • the light projecting optical system projects a light projecting beam emitted by a light emitting unit toward an object and forms a light projecting spot of the light projecting beam on the surface of the object.
  • the light receiving optical system guides a light receiving beam, which is reflected when the light projecting beam strikes the surface of the object, to a light receiving sensor having a plurality of single-photon avalanches arranged in a grid pattern in the vertical and horizontal directions, and forms a light receiving spot of the light receiving beam on the light receiving sensor by imaging the light projecting spot on the light receiving sensor.
  • the size of the light projecting spot in a sub-scanning direction perpendicular to the main scanning direction in which the light projecting beam is deflected is larger than the size of the light projecting spot in the main scanning direction.
  • the light receiving optical system images the light receiving spot on the light receiving sensor with a horizontal resolution perpendicular to the vertical direction and a vertical resolution. The horizontal resolution is lower than the vertical resolution.
  • the distance measuring device comprises a light receiving sensor, a light emitting unit, a light projecting optical system, a deflector, and a light receiving optical system.
  • the light receiving sensor has multiple single-photon avalanche diodes arranged in a grid pattern.
  • the light emitting unit emits a light projecting beam.
  • the light projecting optical system projects the light projecting beam emitted by the light emitting unit toward an object, forming a light projecting spot of the light projecting beam on the surface of the object.
  • the deflector deflects the light projecting beam in the main scanning direction.
  • the light receiving optical system guides a light receiving beam reflected when the light projecting beam is incident on the surface of the object to the light receiving sensor, and forms a light receiving spot of the light receiving beam on the light receiving sensor by imaging the light projecting spot on the light receiving sensor.
  • the size of the light projecting spot in the sub-scanning direction perpendicular to the main scanning direction is larger than the size of the light projecting spot in the main scanning direction.
  • the single-photon avalanche diode is divided into multiple regions arranged vertically corresponding to the sub-scanning direction.
  • the light receiving optical system forms an image of the light receiving spot on the light receiving sensor with a horizontal resolution perpendicular to the vertical direction and a vertical resolution. The horizontal resolution is lower than the vertical resolution.
  • the technology disclosed in this specification contributes to achieving both a wide dynamic range and high spatial resolution.
  • FIG. 1 is a schematic diagram showing the overall configuration of a distance measuring device according to the first embodiment.
  • FIG. 2 is a plan view of the light-receiving sensor.
  • FIG. 3 is a schematic diagram showing the overall configuration of a distance measuring device according to the second embodiment.
  • FIG. 1 is a schematic diagram showing the overall configuration of a distance measuring device 1.
  • the distance measuring device 1 is an optical sensor.
  • the distance measuring device 1 is also called a LiDAR (Light Detection and Ranging), a range sensor, or a laser scanner.
  • the distance measuring device 1 projects a laser beam 5 onto the surface of an object 2 and receives a laser beam 7 reflected by the surface of the object 2.
  • the distance measuring device 1 detects the distance to the surface of the object 2 based on the time difference between the projection and reception of the laser beam.
  • the distance measuring device 1 is a scanning distance measuring device.
  • the distance measuring device 1 deflects the laser beam 5 to trace the surface of the object 2 with a spot 6 of the laser beam 5, thereby detecting the distance and direction to each point on the surface of the object 2.
  • Deflection of the laser beam 5 refers to a change in the emission direction of the laser beam 5.
  • the laser beam 5 projected from the distance measuring device 1 onto the surface of the object 2 is also called the projected beam 5.
  • the laser beam 7 that returns to the distance measuring device 1 after the projected beam 5 strikes the surface of the object 2 and is reflected from that surface is also called the reflected beam 7.
  • the spot 6 of the projected beam 5 refers to a bright area formed on the surface of the object 2 when the projected beam 5 strikes the surface.
  • the spot 6 of the projected beam 5 is also called the projected spot 6.
  • the direction in which the projected beam 5 is deflected, i.e., the direction in which the projected spot 6 moves, is called the main scanning direction.
  • the direction perpendicular to the main scanning direction and parallel to the rotation axis of the deflector 90 is also called the sub-scanning direction.
  • One cycle refers to the period from one light projection to the next.
  • the distance is detected once during one cycle by one light projection and light reception.
  • the projected spot 6 per cycle is resolved into multiple measurement points in the sub-scanning direction.
  • the distance measuring device 1 detects the distance to each measurement point lined up in the sub-scanning direction per cycle.
  • the distance measuring device 1 comprises a light emitting unit 10, an optical device 50, a light receiving sensor 60, and a peripheral circuit 70.
  • the optical device 50 has an optical system and a deflector 90, and the optical system has a light projecting optical system 20, a mirror 30, and a light receiving optical system 40.
  • the peripheral circuit 70 has a signal processing circuit 71 and a time digitizer (TDC: Time-to-Digital Converter) 72.
  • TDC Time-to-Digital Converter
  • the deflector 90 oscillates a unit 80 having the light-emitting unit 10, the light-projecting optical system 20, the mirror 30, the light-receiving optical system 40, and the light-receiving sensor 60. In other words, the deflector 90 rotates the unit 80 reciprocally and continuously around the rotation axis. This causes the projected beam 5 to be deflected in the main scanning direction, and the projected light spot 6 to be displaced in the main scanning direction along the surface of the object 2.
  • the deflector 90 is formed, for example, by a motor.
  • the deflector 90 may alternately deflect the projected beam 5 in the main scanning direction by a predetermined range and deflect the projected beam 5 in the sub-scanning direction by an amount equal to the size of the projected spot 6 in the sub-scanning direction.
  • the light-emitting unit 10 is composed of, for example, a laser diode.
  • the light-emitting unit 10 is driven by a drive circuit, so that the light-emitting unit 10 is periodically turned on. Specifically, the light-emitting unit 10 is turned on once per cycle and outputs the projected beam 5 once per cycle. While the deflector 90 deflects the projected beam 5 in the main scanning direction by a predetermined range, the light-emitting unit 10 outputs the projected beam 5 multiple times.
  • the timing at which the light-emitting unit 10 is turned on is the projection timing.
  • the projected beam 5 is near-infrared light.
  • the projected beam 5 may be visible light or ultraviolet light.
  • the projected beam 5 may have a wavelength range of near-infrared light and visible light.
  • the projected beam 5 may have a wavelength range of visible light and ultraviolet light.
  • the projected beam 5 may have a wavelength range of near-infrared light, visible light, and ultraviolet light.
  • the projection optical system 20 is disposed opposite to the light emitting unit 10 at a distance.
  • the projection optical system 20 collimates the projection beam 5 output by the light emitting unit 10 and projects the projection beam 5 toward the object 2.
  • the projection optical system 20 converts the projection beam 5 into parallel light by reducing the spread angle of the projection beam 5.
  • the projection optical system 20 is, for example, a collimating lens made of a convex lens.
  • the collimating lens is disposed opposite to the light emitting unit 10 at a distance, and its focal point is located at the light emitting unit 10.
  • the mirror 30 is disposed at an angle to the optical axes of the light projecting optical system 20 and the light receiving optical system 40.
  • the center of the mirror 30 is located at the intersection of the optical axes of the light projecting optical system 20 and the light receiving optical system 40.
  • the mirror 30 passes the projecting beam 5 collimated by the light projecting optical system 20, and reflects the reflected beam 7 from the object 2 toward the light receiving sensor 60.
  • the mirror 30 is a prism-type beam splitter or a plate-type beam splitter.
  • the mirror 30 may also be a mirror having a small hole through which the projecting beam 5 passes.
  • the projected light beam 5 that passes through the mirror 30 is incident on the surface of the object 2, and a projected light spot 6 is formed at the point of incidence of the projected light beam 5.
  • the size of the projected light spot 6 in the sub-scanning direction is larger than the size of the projected light spot 6 in the main scanning direction. This is achieved, for example, by making the size of the light-emitting unit 10 in the sub-scanning direction larger than the size of the light-emitting unit 10 in the main scanning direction. This is achieved, for example, by the projecting optical system 20 making the spread angle of the projected light beam 5 in the sub-scanning direction smaller than the spread angle of the projected light beam 5 in the main scanning direction.
  • the projected beam 5 is reflected by the surface of the object 2.
  • the reflection of the projected beam 5 is, for example, diffuse reflection.
  • a component reflected in the opposite direction to the projected beam 5 returns to the mirror 30 as a reflected beam 7.
  • the reflected beam 7 travels along the same path as the projected beam 5, but in the opposite direction, and reaches the mirror 30.
  • the mirror 30 makes the optical axis of the reflected beam 7 from the object 2 to the mirror 30 coaxial with the optical axis of the projected beam 5 from the mirror 30 to the object 2.
  • the mirror 30 reflects the reflected beam 7 toward the light-receiving optical system 40 and the light-receiving sensor 60.
  • the light-receiving optical system 40 is disposed between the mirror 30 and the light-receiving sensor 60.
  • the light-receiving optical system 40 guides the reflected beam 7 reflected by the mirror 30 to the light-receiving sensor 60, thereby forming a spot 8 of the reflected beam 7 on the light-receiving sensor 60.
  • the light-receiving optical system 40 forms an image of the projected spot 6 on the light-receiving sensor 60, thereby forming a spot 8 of the reflected beam 7 on the light-receiving sensor 60.
  • the spot 8 of the reflected beam 7 is an image of the projected spot 6.
  • the spot 8 of the reflected beam 7 is called a received spot 8.
  • the size of the light received spot 8 in the vertical direction is larger than the size of the light received spot 8 in the horizontal direction.
  • the vertical direction refers to the direction along the light receiving surface of the light receiving sensor 60 and parallel to the sub-scanning direction.
  • the horizontal direction refers to the direction along the light receiving surface of the light receiving sensor 60 and perpendicular to the vertical direction.
  • the horizontal direction on the light receiving surface of the light receiving sensor 60 corresponds to the main scanning direction on the surface of the object 2
  • the vertical direction on the light receiving surface of the light receiving sensor 60 corresponds to the sub-scanning direction on the surface of the object 2.
  • the light receiving optical system 40 resolves the light receiving spot 8 onto the light receiving sensor 60 with a vertical resolution and a horizontal resolution that is lower than the vertical resolution. Therefore, the blur of the light receiving spot 8 in the horizontal direction is greater than the blur of the light receiving spot 8 in the vertical direction.
  • the light-receiving optical system 40 has a condenser lens 41 and an anisotropic optical element 42.
  • a mirror 30, condenser lens 41, anisotropic optical element 42, and a light-receiving sensor 60 are arranged in this order.
  • the condenser lens 41 condenses the reflected beam 7 reflected by the mirror 30 and forms a projected light spot 6 on the light-receiving sensor 60, thereby forming a received light spot 8 on the light-receiving sensor 60.
  • the anisotropic optical element 42 has different refractive powers in the horizontal and vertical directions.
  • the anisotropic optical element 42 spreads the reflected beam 7 in the horizontal direction and blurs the light-receiving spot 8 in the horizontal direction. As a result, the light-receiving spot 8 is blurred more in the horizontal direction than in the vertical direction.
  • the anisotropic optical element 42 may spread the reflected beam 7 in the horizontal direction so that the reflected beam 7 becomes top-hat shaped.
  • the top-hat shaped reflected beam 7 has a uniform intensity distribution in the center of the reflected beam 7.
  • the anisotropic optical element 42 is an optical element such as a cylindrical lens, an anamorphic lens, a diffraction grating, or a beam splitter. These optical elements have optical properties that spread the reflected beam 7 laterally and blur the received light spot 8 laterally.
  • the light-receiving sensor 60 is disposed on the opposite side of the mirror 30 with respect to the light-receiving optical system 40.
  • the light-receiving sensor 60 is perpendicular to the optical axis of the light-receiving optical system 40.
  • FIG. 2 is a plan view of the light-receiving sensor 60.
  • the light-receiving sensor 60 is a sensor array such as a multi-pixel photon counter (MPPC), a silicon photomultiplier (SiPM), or a pixelated photon detector (PPD). That is, the light-receiving sensor 60 has a plurality of photoelectric conversion elements 61 arranged in a grid pattern, that is, vertically and horizontally.
  • the photoelectric conversion elements 61 have single-photon avalanche diodes (SAPDs) driven in Geiger mode and quenching resistors. Because the photoelectric conversion elements 61 are driven in Geiger mode, their light-receiving sensitivity is high.
  • SAPDs single-photon avalanche diodes
  • the photoelectric conversion elements 61 sense the photon and the output signal of the photoelectric conversion elements 61 becomes saturated. If the photoelectric conversion element 61 does not receive a single photon, the output signal from the photoelectric conversion element 61 will not saturate.
  • the number of photoelectric conversion elements 61 arranged vertically is greater than the number of photoelectric conversion elements 61 arranged horizontally.
  • These photoelectric conversion elements 61 are divided into multiple regions 65, and these regions 65 are arranged vertically. These regions 65 are rectangular.
  • the horizontal size of each region 65 is greater than the vertical size of each region 65. Specifically, the horizontal size of each region 65 is more than 1 time and less than 10 times the vertical size of each region 65.
  • the number of photoelectric conversion elements 61 arranged in the horizontal direction within each region 65 is greater than the number of photoelectric conversion elements 61 arranged in the vertical direction within each region 65.
  • the number of photoelectric conversion elements 61 arranged in the horizontal direction within each region 65 is more than 1 time and not more than 10 times the number of photoelectric conversion elements 61 arranged in the vertical direction within each region 65.
  • the photoelectric conversion elements 61 are divided into 600 regions 65, and the number of photoelectric conversion elements 61 arranged in the horizontal direction within each region 65 is 30, and the number of photoelectric conversion elements 61 arranged in the vertical direction within each region 65 is 3.
  • the field of view of the light receiving optical system 40 on the surface of the object 2 corresponding to region 65 is such that the field of view in the main scanning direction is wider than the field of view in the sub-scanning direction. Specifically, the field of view in the main scanning direction is greater than 1 time and less than 10 times the field of view in the sub-scanning direction.
  • region 65 When region 65 is divided horizontally, region 65 has a central portion 66 and side portions 67, 68, with side portion 67, central portion 66, and side portion 68 arranged in the horizontal direction, in that order. Side portions 67, 68 are the portions of region 65 other than central portion 66.
  • the light receiving spot 8 formed by the condenser lens 41 and the anisotropic optical element 42 spreads across the entire light receiving surface of the light receiving sensor 60, so the light receiving spot 8 covers the entire area 65.
  • the light-receiving sensor 60 is connected to a signal processing circuit 71.
  • the light-receiving sensor 60 outputs an output signal from the photoelectric conversion element 61 for each region 65 to the signal processing circuit 71.
  • the signal processing circuit 71 counts the number of photoelectric conversion elements 61 that have sensed a photon for each region 65, for each unit time that is sufficiently shorter than one cycle period. Because the output signal of the photoelectric conversion element 61 that senses a photon becomes saturated, the signal processing circuit 71 compares the output signal of the photoelectric conversion element 61 with a saturation value for each photoelectric conversion element 61.
  • the signal processing circuit 71 increments a count value that represents the number of photoelectric conversion elements 61 that have sensed a photon.
  • the count value for each region 65 represents the received light intensity of the reflected beam 7 for each region 65.
  • the signal processing circuit 71 outputs a signal representing the received light intensity of the reflected beam 7 for each region 65 in a time series.
  • the value of the signal for each region 65 output by the signal processing circuit 71 represents the received light intensity of the reflected beam 7 per unit time, i.e., the number of photoelectric conversion elements 61 that sense photons.
  • the timing at which the signal for each region 65 output by the signal processing circuit 71 reaches its peak is the timing at which the reflected beam 7 is received in that region 65.
  • the signal processing circuit 71 ignores the output signals of the photoelectric conversion elements 61 in the central portion 66 and ignores the number of photoelectric conversion elements 61 in the central portion 66. Therefore, the value of the signal for each region 65 output by the signal processing circuit 71 represents the received light intensity of the reflected beam 7 incident on the side portions 67 and 68, i.e., the number of photoelectric conversion elements 61 in the side portions 67 and 68 that sensed photons.
  • the time digitizer 73 receives the signal for each region 65 output by the signal processing circuit 71.
  • the time digitizer 73 receives a pulse signal that rises at the lighting timing of the light-emitting unit 10, i.e., the light-projection timing.
  • the time digitizer 73 calculates the time difference for each region 65 from the light-projection timing to the light-reception timing based on the signal for each region 65 and the pulse signal input from the signal processing circuit 71.
  • the time digitizer 73 outputs a digital signal representing the calculated time difference.
  • the time difference for each region 65 corresponds to the distance to each measurement point overlapping the light projection spot 6.
  • the light-projection timing at which the pulse signal rises represents the emission direction, i.e., the orientation, of the light projection beam 5.
  • the distance measuring device 1 includes a light-emitting unit 10, a light-projecting optical system 20, a light-receiving optical system 40, a light-receiving sensor 60, and a deflector 90.
  • the light-emitting unit 10 emits a light-projecting beam 5.
  • the light-projecting optical system 20 projects the light-projecting beam 5 toward an object 2 to form a light-projected spot 6 of the light-projecting beam 5 on the surface of the object 2.
  • the deflector 90 deflects the light-projecting beam 5 in the main scanning direction.
  • the light-receiving optical system 40 guides a reflected beam 7, which is generated when the light-projecting beam 5 is incident on the surface of the object 2 and reflected, to the light-receiving sensor 60.
  • the light-receiving optical system 40 forms a light-receiving spot 8 of the reflected beam 7 on the light-receiving sensor 60 by focusing the light-projected spot 6 on the light-receiving sensor 60.
  • the light-receiving optical system 40 resolves the light-receiving spot 8 on the light-receiving sensor 60 with a vertical resolution and a horizontal resolution that is lower than the vertical resolution.
  • the size of the projected light spot 6 in the sub-scanning direction is larger than the size of the projected light spot 6 in the main scanning direction.
  • the light-receiving sensor 60 has a plurality of photoelectric conversion elements 61 arranged in a grid pattern in the vertical and horizontal directions.
  • the photoelectric conversion elements 61 are divided into a plurality of regions 65 arranged in the vertical direction.
  • the light-receiving sensor 60 outputs an output signal from the photoelectric conversion element 61 for each region 65.
  • This distance measuring device 1 contributes to improving the dynamic range when the received light intensity of the reflected beam 7 incident on each region 65 is converted into a signal.
  • the received light intensity of the reflected beam 7 incident on each region 65 is expressed in levels corresponding to the number of photoelectric conversion elements 61.
  • the wide dynamic range of the signal of the received light intensity of the reflected beam 7 incident on each region 65 makes it easier to extract only the signal of the reflected beam from the object from noise due to ambient light such as sunlight, contributing to improved measurement accuracy of the light-receiving timing and further contributing to improved distance measurement accuracy. Furthermore, such a distance measuring device 1 contributes to improved spatial resolution in the sub-scanning direction.
  • the light-receiving surface of the light-receiving sensor 60 is divided into multiple regions 65, these regions 65 are arranged vertically, and the light-receiving sensor 60 outputs an output signal from the photoelectric conversion element 61 for each region 65. Therefore, the distance to each of the multiple measurement points arranged in the sub-scanning direction in the light-projected spot 6 can be detected individually for each measurement point.
  • the light-projecting spot 6 is imaged as a light-receiving spot 8 on the light-receiving sensor 60 by the light-receiving optical system 40. Because the horizontal resolution of the light-receiving spot 8 is lower than the horizontal resolution of the light-receiving spot 8, the reflected light from multiple measurement points arranged in the sub-scanning direction in the light-projecting spot 6 spreads horizontally and is incident on multiple regions 65, respectively. As a result, the dynamic range of the signal representing the received light intensity of the reflected beam 7 incident on each region 65 is wide, and the spatial resolution in the sub-scanning direction is high.
  • the size of the light projection spot 6 in the sub-scanning direction is larger than the size of the light projection spot 6 in the main scanning direction.
  • Such a size of the light projection spot 6 contributes to a wide dynamic range in the signal of the received light intensity of the reflected beam 7 incident on each region 65.
  • Such a size of the light projection spot 6 contributes to high spatial resolution in the sub-scanning direction.
  • Such a size of the light projection spot 6 contributes to an improvement in the signal-to-noise ratio when the received light intensity of the reflected beam 7 incident on each region 65 is converted into a signal.
  • the photoelectric conversion element 61 of the light receiving sensor 60 is driven in Geiger mode, the photoelectric conversion element 61 has high light receiving sensitivity. Therefore, even if the distance from the distance measuring device 1 to the object 2 is long and the intensity of the reflected beam 7 is attenuated, the distance measuring device 1 can still measure the distance.
  • the reason why the horizontal arrangement number of photoelectric conversion elements 61 in each region 65 is more than 1 time the vertical arrangement number of photoelectric conversion elements 61 in each region 65 is to ensure high vertical resolution of the projected light spot 6.
  • the size of region 65 in the horizontal direction is larger than the size of region 65 in the vertical direction.
  • the size of region 65 in the horizontal direction is more than 1 time and not more than 10 times the size of region 65 in the vertical direction. Therefore, the dynamic range of the signal of the received light intensity of reflected beam 7 incident on each region 65 is wide, and the spatial resolution in the sub-scanning direction is high.
  • the size of region 65 in the horizontal direction is set to not more than 10 times the size of region 65 in the vertical direction in order to prevent a deterioration in the signal-to-noise ratio when the received light intensity of reflected beam 7 is converted into a signal.
  • the size of region 65 in the horizontal direction is set to more than 1 time the size of region 65 in the vertical direction in order to prevent the dynamic range from becoming narrow.
  • the field of view in the main scanning direction is wider than the field of view in the sub-scanning direction.
  • the field of view in the main scanning direction is more than 1 time and less than 10 times the field of view in the sub-scanning direction. Therefore, the dynamic range of the signal of the received light intensity of the reflected beam 7 incident on each region 65 is wide, the spatial resolution in the sub-scanning direction is high, and the resolution in the scanning direction is high.
  • the field of view in the scanning direction is set to 10 times or less the field of view in the sub-scanning direction to prevent a deterioration in the signal-to-noise ratio when the received light intensity of the reflected beam 7 is converted into a signal.
  • the field of view in the main scanning direction is set to more than 1 time the field of view in the sub-scanning direction to prevent a narrowing of the dynamic range.
  • the mirror 30 makes the optical axis of the projected beam 5 from the mirror 30 to the object 2 coaxial with the optical axis of the reflected beam 7 from the object 2 to the mirror 30.
  • the effect of any object between the mirror 30 and the object 2, such as air or a transparent window, on the projected beam 5 is approximately the same as the effect that this object has on the reflected beam 7. This contributes to improving the measurement accuracy of the light reception timing, and further contributes to improving the distance measurement accuracy.
  • Second Embodiment 3 is a schematic diagram showing the overall configuration of the distance measuring device 1A. Corresponding components between the distance measuring device 1A of the second embodiment and the distance measuring device 1 of the first embodiment are denoted by the same reference numerals. The distance measuring device 1A of the second embodiment differs from the distance measuring device 1 of the first embodiment in the following points.
  • the deflector 90 swings the unit 80, thereby deflecting the projected beam 5 in the main scanning direction.
  • the deflector 90 is of a polygon mirror type. Specifically, the deflector 90 has a polygon mirror 91 and a motor 92.
  • the polygon mirror 91 has multiple mirror surfaces 91a on its outer circumferential surface, and these mirror surfaces 91a are arranged along the outer circumferential surface to form a polygonal cylindrical surface.
  • the polygon mirror 91 is arranged on the opposite side of the projection optical system 20 with respect to the mirror 30.
  • the projection beam 5 is incident on the mirror surface 91a and is reflected by the mirror surface 91a towards the object 2.
  • the motor 92 drives the polygon mirror 91 to rotate, thereby changing the orientation of the mirror surface 91a.
  • the change in orientation of the mirror surface 91a contributes to deflecting the projection beam 5 in the main scanning direction.
  • Mirror 30 makes the optical axis of reflected beam 7 from object 2 to mirror 30 coaxial with the optical axis of projected beam 5 from mirror 30 to object 2. Therefore, the position at which projected beam 5 is incident on mirror surface 91a coincides with the position at which reflected beam 7 is incident on mirror surface 91a. As a result, the effect of manufacturing errors in mirror surface 91a on projected beam 5 is about the same as the effect that manufacturing errors in mirror surface 91a have on reflected beam 7. This contributes to improved measurement accuracy of light reception timing, and further contributes to improved ranging accuracy.
  • An optical system comprising: a light projection optical system that projects a light projection beam emitted by a light emitting unit toward an object and forms a light projection spot of the light projection beam on the surface of the object; and a light receiving optical system that guides a light reception beam reflected by the light projection beam incident on the surface of the object to a light receiving sensor having a plurality of single-photon avalanche diodes arranged in a grid pattern in the vertical and horizontal directions, and forms a light reception spot of the received light beam on the light receiving sensor by imaging the light projection spot on the light receiving sensor, wherein the size of the light projection spot in the sub-scanning direction perpendicular to the main scanning direction in which the light projection beam is deflected is larger than the size of the light projection spot in the main scanning direction, and the light receiving optical system images the light reception spot on the light receiving sensor with a horizontal resolution perpendicular to the vertical direction and a vertical resolution, and the horizontal resolution is lower than the vertical resolution.
  • An optical system according to (1) or (2) in which the single-photon avalanche diode is divided into a plurality of regions arranged in the vertical direction, and the field of view of the light-receiving optical system on the surface of the object, which corresponds to the region, is such that the field of view in the main scanning direction is more than 1 time and not more than 10 times the field of view in the sub-scanning direction.
  • any one of the optical systems (1) to (3) comprising a mirror that passes the projecting beam projected by the projecting optical system and reflects the receiving beam reflected by the surface of the object toward the receiving optical system and the light-receiving sensor, wherein the mirror makes the optical axis of the projecting beam from the mirror to the object coaxial with the optical axis of the receiving beam from the object to the mirror.
  • a light receiving sensor having a plurality of single-photon avalanche diodes arranged in a grid pattern; a light emitting unit that emits a light projection beam; a light projection optical system that projects the light projection beam emitted by the light emitting unit toward an object and forms a light projection spot of the light projection beam on the surface of the object; a deflector that deflects the light projection beam in the main scanning direction; and a light receiving beam that is reflected by the light projection beam incident on the surface of the object and guides it to the light receiving sensor, and forms a light receiving spot of the received beam by imaging the light projection spot on the light receiving sensor.
  • a light-receiving optical system that forms a light-receiving spot on the light-receiving sensor; wherein the size of the light-projected spot in a sub-scanning direction perpendicular to the main scanning direction is larger than the size of the light-projected spot in the main scanning direction; the single-photon avalanche diode is divided into multiple regions arranged in a vertical direction corresponding to the sub-scanning direction; the light-receiving optical system forms an image of the light-receiving spot on the light-receiving sensor with a horizontal resolution perpendicular to the vertical direction and a vertical resolution, and the horizontal resolution is lower than the vertical resolution.
  • a distance measuring device in which the number of single-photon avalanche diodes arranged horizontally within the region is greater than the number of single-photon avalanche diodes arranged vertically within the region.
  • a distance measuring device wherein the number of single-photon avalanche diodes arranged in the horizontal direction within the region is more than 1 time and not more than 10 times the number of single-photon avalanche diodes arranged in the vertical direction within the region.
  • a distance measuring device according to any one of (7) to (9), further comprising a signal processing circuit that inputs the output signal of the single-photon avalanche diode output by the light receiving sensor, and when the output signal of the single-photon avalanche diode located in the center of the region is saturated, the signal processing circuit ignores the output signal of the single-photon avalanche diode located in the center of the region.
  • a distance measuring device according to any one of (7) to (10), wherein the light receiving sensor outputs an output signal of the single-photon avalanche diode for each of the regions.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Electromagnetism (AREA)
  • Optical Radar Systems And Details Thereof (AREA)

Abstract

La présente invention a pour objectif d'obtenir à la fois une large plage dynamique et une résolution spatiale élevée.　Ce dispositif de mesure de distance est pourvu d'un capteur de réception de lumière, d'une unité électroluminescente, d'un système optique de projection de lumière, d'un déflecteur et d'un système optique de réception de lumière. Le capteur de réception de lumière comporte une pluralité de diodes à avalanche à photon unique disposées dans une grille. L'unité électroluminescente émet un faisceau de projection de lumière. Le système optique de projection de lumière forme un point de projection de lumière du faisceau de projection de lumière sur la surface de l'objet. Le système optique de réception de lumière forme un point de réception de lumière sur le capteur de réception de lumière en formant une image du point de projection de lumière sur le capteur de réception de lumière. La taille du point de projection de lumière dans la direction de balayage secondaire est supérieure à la taille du point de projection de lumière dans la direction de balayage principale. Les diodes à avalanche à photon unique sont divisées en une pluralité de régions agencées dans la direction verticale. La résolution horizontale du point de réception de lumière est inférieure à la résolution verticale du point de réception de lumière.
PCT/JP2025/013999 2024-05-15 2025-04-08 Système optique et dispositif de mesure de distance Pending WO2025239064A1 (fr)

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JP2024-079110 2024-05-15

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005249742A (ja) * 2004-03-08 2005-09-15 Omron Corp レーダ装置
JP2014006110A (ja) * 2012-06-22 2014-01-16 Konica Minolta Inc レーザレーダ
US20180180470A1 (en) * 2016-12-22 2018-06-28 Sick Ag Light receiver having a plurality of avalanche photodiode elements and method for detecting light
JP2018105746A (ja) * 2016-12-27 2018-07-05 パイオニア株式会社 計測装置及び制御方法
JP2020118567A (ja) * 2019-01-24 2020-08-06 ソニーセミコンダクタソリューションズ株式会社 測距装置、車載システム及び測距方法
JP2021063800A (ja) * 2019-10-16 2021-04-22 株式会社デンソー 車載の異常検出装置

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005249742A (ja) * 2004-03-08 2005-09-15 Omron Corp レーダ装置
JP2014006110A (ja) * 2012-06-22 2014-01-16 Konica Minolta Inc レーザレーダ
US20180180470A1 (en) * 2016-12-22 2018-06-28 Sick Ag Light receiver having a plurality of avalanche photodiode elements and method for detecting light
JP2018105746A (ja) * 2016-12-27 2018-07-05 パイオニア株式会社 計測装置及び制御方法
JP2020118567A (ja) * 2019-01-24 2020-08-06 ソニーセミコンダクタソリューションズ株式会社 測距装置、車載システム及び測距方法
JP2021063800A (ja) * 2019-10-16 2021-04-22 株式会社デンソー 車載の異常検出装置

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