WO2019163754A1 - Dispositif miroir, dispositif de balayage optique, dispositif de mesure de distance, procédé de commande destiné à un dispositif miroir et programme - Google Patents

Dispositif miroir, dispositif de balayage optique, dispositif de mesure de distance, procédé de commande destiné à un dispositif miroir et programme Download PDF

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Publication number
WO2019163754A1
WO2019163754A1 PCT/JP2019/006051 JP2019006051W WO2019163754A1 WO 2019163754 A1 WO2019163754 A1 WO 2019163754A1 JP 2019006051 W JP2019006051 W JP 2019006051W WO 2019163754 A1 WO2019163754 A1 WO 2019163754A1
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WIPO (PCT)
Prior art keywords
frequency
mirror
oscillating
drive
resonance frequency
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PCT/JP2019/006051
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English (en)
Japanese (ja)
Inventor
奥田　義行
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パイオニア株式会社
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Publication of WO2019163754A1 publication Critical patent/WO2019163754A1/fr

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C3/00—Measuring distances in line of sight; Optical rangefinders
    • G01C3/02—Details
    • G01C3/06—Use of electric means to obtain final indication
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/481—Constructional features, e.g. arrangements of optical elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
    • G02B26/10—Scanning systems

Definitions

  • the present invention relates to a mirror device including a swing mirror, an optical scanning device that performs optical scanning with the mirror device, and a distance measuring device that performs optical distance measurement with the optical scanning device.
  • the distance measuring device is configured to measure the distance to the object by irradiating the object in a predetermined region and detecting the light reflected by the object.
  • a distance measuring device that has an optical scanning device that scans the area in a two-dimensional manner and obtains a two-dimensional distance measurement result in the area is known.
  • the optical scanning type distance measuring device includes, as an optical scanning device, a MEMS (Micro Electro Mechanical Systems) mirror, a light source that irradiates light to the mirror, and a light receiving unit that receives reflected light from an object.
  • the optical scanning device uses the light reflected by the mirror to scan the scanning area two-dimensionally.
  • Patent Document 1 discloses a radar apparatus having a scanner that performs two-dimensional scanning using infrared pulsed light.
  • a movable mirror such as a MEMS mirror has a light reflecting surface that oscillates around two oscillating axes (rotating axes) orthogonal to each other, for example.
  • a drive circuit for driving the mirror is connected to the mirror.
  • the drive circuit generates, for example, a drive signal that swings the light reflecting surface of the mirror, and supplies this to the mirror.
  • the movable mirror has a specific resonance frequency according to the material. Therefore, when a drive signal having a frequency about the resonance frequency is supplied to the mirror, the mirror reaches a resonance state and oscillates with a larger amplitude than that in the non-resonance state. Therefore, by resonating the mirror, the range of light reflection by the mirror is expanded, and a large range can be scanned.
  • the resonance frequency of the mirror varies depending on the temperature of the material constituting the mirror. Therefore, for example, the resonance frequency of the mirror fluctuates as the operating environment of the optical scanning device changes and the operating time advances.
  • the oscillation state of the mirror for example, each of the oscillation period and amplitude around the two oscillation axes slightly changes, and for example, the shape and size of the scanning region and the scanning trajectory (scanning pattern) of the light change. There is a case.
  • the scanning trajectory changes greatly because the ratio of the oscillation period around the two oscillation axes varies.
  • the least common multiple of the two oscillation cycles is reduced, the overlapping portions of the scanning trajectories in one scanning cycle are increased. Therefore, the number of scanning points in the scanning region is greatly reduced, and the scanning points in the scanning region are likely to be biased.
  • the present invention has been made in view of the above points, and includes a mirror device having a oscillating mirror that stably oscillates around two oscillating shafts, an optical scanning device including the mirror device, and a distance measuring device. Providing is one of the issues. Another object of the present invention is to provide a method and a program for stably driving a oscillating mirror that oscillates around two oscillation axes.
  • an oscillating mirror that oscillates around different first and second axes, and a first for the oscillating mirror to oscillate around the first and second axes, respectively.
  • a drive circuit for generating a second drive signal, and the drive circuit determines a swing frequency around the first and second axes of the swing mirror based on the swing state of the swing mirror.
  • the first drive signal and the second drive signal are generated so that the ratio between the first oscillation frequency and the second oscillation frequency of the oscillation mirror is within a predetermined range.
  • the invention according to claim 5 includes the mirror device according to claim 1 and a light source unit that emits light toward the oscillating mirror, and the oscillating mirror emits light from the light source unit. By reflecting the light, it functions as a scanning unit that scans a predetermined region with a trajectory along the Lissajous curve using the emitted light.
  • the optical scanning device according to the fifth aspect of the present invention, and a distance measuring unit that measures the distance to the object based on the reflected light from the object existing in a predetermined area. It is characterized by having.
  • the first and second drive signals are supplied to cause the oscillating mirror to oscillate around different first and second axes, and the oscillating mirror Determining the first and second oscillation frequencies around the first and second axes of the oscillating mirror based on the oscillating state, and the ratio between the first and second oscillating frequencies is within a predetermined range. Adjusting the frequency of the first and second drive signals so as to be inside.
  • the computer supplies the first and second drive signals to the oscillating mirrors that oscillate around the first and second axes different from each other.
  • the first and second oscillation frequencies around the first and second axes of the oscillating mirror are determined based on the moving state, and the ratio between the first and second oscillation frequencies is within a predetermined range. Further, it is characterized by functioning as a drive circuit for adjusting the frequency of the first and second drive signals.
  • FIG. 1 is a layout diagram of a distance measuring apparatus according to Embodiment 1.
  • FIG. 1 is a configuration diagram of a mirror device in a distance measuring device according to Embodiment 1.
  • FIG. 3 is a circuit diagram of a drive circuit of a mirror device in the distance measuring apparatus according to Embodiment 1.
  • FIG. FIG. 6 is a diagram illustrating a driving signal applied to a swing mirror and a scanning mode of an optical scanning unit in the distance measuring apparatus according to the first embodiment. It is a figure which shows the drive flow of the mirror apparatus in the ranging apparatus which concerns on Example 1.
  • FIG. FIG. 6 is a diagram illustrating an example of adjusting the frequency of a drive signal applied to the mirror device of the distance measuring apparatus according to the first embodiment.
  • FIG. 6 is a diagram illustrating an example of adjusting the frequency of a drive signal applied to the mirror device of the distance measuring apparatus according to the first embodiment.
  • FIG. 1 is a schematic layout diagram of the distance measuring apparatus 10 according to the first embodiment.
  • the distance measuring device 10 performs optical scanning of a predetermined area (hereinafter referred to as a scanning area) R0, and based on the scanning result, determines a distance to an object (ranging object) OB present in the scanning area R0. It is an optical distance measuring device to measure.
  • the overall configuration of the distance measuring device 10 will be described with reference to FIG. FIG. 1 schematically shows the scanning region R0 and the object OB.
  • the distance measuring device 10 periodically scans the scanning region R0 with pulsed laser light (hereinafter referred to as emission light) L1, and receives reflected light L3 from the object OB in the scanning region R0.
  • An optical scanning device SC that acquires optical scanning information in the scanning region R0 is included.
  • the optical scanning device SC includes a light source unit 11 that generates and emits the emitted light L1.
  • the light source unit 11 includes a laser device that generates laser light having a peak wavelength in the infrared region as the emitted light L1.
  • the optical scanning device SC includes the mirror device 12 that reflects the outgoing light L1 and emits the outgoing light L1 toward the scanning region R0 by changing the reflection direction continuously and periodically.
  • the mirror device 12 functions as a scanning unit (light sweep unit) in the optical scanning device SC.
  • the mirror device 12 has a oscillating mirror provided with a light reflecting surface 12A that reflects the emitted light L1 toward the scanning region R0.
  • the mirror device 12 continuously and periodically changes the direction in which the emitted light L1 is reflected by changing the direction of the light reflecting surface 12A.
  • the optical scanning device SC performs the optical scanning of the scanning region R0 using the outgoing light L1 reflected by the light reflecting surface 12A as the scanning light L2.
  • the scanning region R0 has a width and height corresponding to the movable range of the light reflecting surface 12A, and receives the reflected light L3 having a predetermined intensity when the scanning light L2 reaches and reflects.
  • a virtual three-dimensional space having a depth corresponding to a possible distance.
  • the outer edge of the scanning region R0 is indicated by a broken line.
  • the scanning light L2 is irradiated to the object OB. Further, when the object OB is an object having a characteristic of reflecting the scanning light L2, the scanning light L2 is reflected by the object OB.
  • the optical scanning device SC includes a light receiving unit 13 that receives and detects reflected light L3, that is, light reflected by the object OB when the object OB is irradiated with the reflected light L3.
  • the light receiving unit 13 includes, for example, a photodetector that detects light in a wavelength band including the wavelength of the emitted light L1.
  • the light receiving unit 13 performs photoelectric conversion on the received reflected light L3, and generates an electrical signal (hereinafter referred to as a received light signal) SR corresponding to the reflected light L3.
  • a beam splitter BS is provided on the optical path of the emitted light L1 between the light source unit 11 and the light reflecting surface 12A of the mirror device 12.
  • the scanning light L2 is reflected by the object OB to become reflected light L3, and returns toward the light reflecting surface 12A.
  • the reflected light L3 is reflected by the light reflecting surface 12A, separated by the beam splitter BS, and then received by the light receiving unit 13.
  • the emitted light L1 from the light source unit 11 passes through the beam splitter BS and travels toward the mirror device 12.
  • the distance measuring device 10 includes a distance measuring unit 14 that measures the distance to the object OB based on the light reception signal SR.
  • the distance measuring unit 14 detects the pulse of the reflected light L3 from the light reception signal SR, and the object OB (and a part of the surface thereof) by the time-of-flight method based on the time difference from the emission of the emission light L1. Measure the distance to the area.
  • the distance measuring unit 14 generates data (hereinafter referred to as distance measurement data) indicating the measured distance information.
  • the distance measuring unit 14 images the scanning region R0 based on the distance measurement data.
  • the distance measurement unit 14 generates distance measurement image data in which the emission direction of the scanning light L2 (that is, the direction of the light reflecting surface 12A in the mirror device 12) is associated with the distance measurement data.
  • the distance measuring unit 14 generates one distance image data for each scanning cycle of the optical scanning device SC, that is, for each oscillation cycle of the mirror device 12.
  • the ranging unit 14 may include a display unit (not shown) that displays the plurality of ranging image data as a moving image in time series.
  • the scanning cycle is, for example, when scanning is periodically performed on the scanning region R0, from the time of an arbitrary scanning state (for example, the direction of the light reflecting surface 12A that emits the scanning light L2), and then the scanning again. The period up to the point of returning to the state.
  • the optical scanning device SC scans the scanning region R0 using the scanning light L2 (emitted light L1), and outputs the scanning result (optical scanning information) as the light receiving signal SR.
  • the distance measuring device 10 optically measures the distance to the object OB based on the optical scanning information, and outputs the distance measurement result as distance measurement data (or distance measurement image data).
  • FIG. 2 is a schematic top view showing the configuration of the mirror device 12.
  • the mirror device 12 includes a oscillating mirror 20 and a drive circuit 30 that drives the oscillating mirror 20.
  • the oscillating mirror 20 is a MEMS (Micro Electro Mechanical Systems) mirror that includes a light reflecting film 24 having a light reflecting surface 12A, and the light reflecting film 24 oscillates.
  • MEMS Micro Electro Mechanical Systems
  • the oscillating mirror 20 has a fixed portion 21 and an oscillating portion 22.
  • the swinging part 22 swings around first and second axes (hereinafter referred to as swinging axes) AX and AY that are orthogonal to each other.
  • the fixed portion 21 functions as a support portion that supports the swinging portion 22 so as to be swingable.
  • the fixed portion 21 has a frame (fixed frame) that surrounds the swing portion 22 and suspends the swing portion 22 inside thereof.
  • the rocking part 22 includes a pair of torsion bars (first torsion bars) TX each having one end fixed inside the fixing part 21.
  • Each of the pair of torsion bars TX is made of a rod-shaped elastic member having at least circumferential elasticity, and is aligned along the first swing axis AX.
  • the swinging part 22 has an annular swinging frame SX whose outer peripheral side surface is connected to the other end of each of the pair of torsion bars TX.
  • each swinging portion 22 is connected to the side surface of the inner peripheral portion of the swinging frame SX and aligned in a direction perpendicular to the pair of torsion bars TX (a direction along the second swinging axis AY). It has a pair of torsion bars (second torsion bar) TY and a swing plate SY whose outer peripheral side surface is connected to the other end of each of the pair of torsion bars TY.
  • Each of the pair of torsion bars TY is composed of a rod-like elastic member having at least circumferential elasticity.
  • the swing frame SX swings around the first swing axis AX (about the first swing axis AX), and the swing plate SY swings between the first and second swing axes. Swing around axes AX and AY.
  • a light reflecting film 24 is formed on the swing plate SY. Accordingly, the light reflecting surface 12A of the light reflecting film 24 swings around the first and second swing axes AX and AY orthogonal to each other together with the swing plate SY.
  • the oscillating mirror 20 functions as a scanning unit that scans the scanning region R0 using the emitted light L1 in the optical scanning device SC by continuously changing the reflection direction of the emitted light L1.
  • the oscillating mirror 20 includes an electrode group (hereinafter referred to as a drive electrode group) 23 to which drive signals (first and second drive signals) DX and DY from the drive circuit 30 are supplied.
  • the drive electrode group 23 includes a first drive electrode 23X to which a first drive signal DX is supplied and a second drive electrode 23Y to which a second drive signal DY is supplied.
  • the swing unit 22 swings around the first swing axis AX by the first drive signal DX, and swings around the second swing axis AY by the second drive signal DY.
  • the oscillating mirror 20 generates an oscillating force generating unit (a driving force of the oscillating unit 22) that generates an oscillating force that oscillates the oscillating unit 22 by applying the drive signals DX and DY (see FIG. Not shown).
  • the swinging force of the swinging unit 22 include piezoelectric, electromagnetic, electrostatic or thermal force.
  • the oscillating mirror 20 has a detection unit (not shown) that detects the oscillating state of the oscillating unit 22 (light reflecting surface 12A).
  • the detection unit detects the swinging state of the swinging unit 22, for example, the direction of the swinging plate SY (swing angles about the first and second swinging axes AX and AY with respect to the fixed unit 21) piezoelectrically and electrostatically. Detecting electromagnetically or thermally.
  • the oscillating mirror 20 is an electrode group (hereinafter referred to as a detection electrode group) 25 that outputs signals (hereinafter referred to as detection signals) EX and EY indicating the oscillating state of the oscillating part 22 detected by the detection unit.
  • the detection electrode group 25 includes a first detection electrode 25X that outputs the swing angle of the swing portion 22 around the first swing axis AX as a potential difference, and a second detection electrode 25X. And a second detection electrode 25Y that outputs a swing angle around the swing axis AY as a potential difference.
  • the drive circuit 30 includes a drive signal generation unit 31 that generates the drive signals DX and DY.
  • the drive circuit 30 also detects the first and second swing axes AX and AY of the swing mirror 20 based on the detection signals EX and EY from the swing mirror 20 (that is, the swing state of the swing mirror 20).
  • a resonance frequency determination unit 32 for determining the surrounding resonance frequency is included. Further, the resonance frequency determination unit 32 determines and monitors the frequency during which the oscillating mirror 20 is oscillating (hereinafter referred to as the oscillating frequency) based on the oscillation state of the oscillating mirror 20.
  • the drive circuit 30 determines the frequency of the first and second drive signals DX and DY based on the change in the ratio of the resonance frequencies around the first and second swing axes AX and AY of the swing mirror 20.
  • it has a drive frequency adjusting unit 33 that adjusts the drive frequency.
  • the drive frequency adjusting unit 33 compares the resonance frequencies around the first and second swing axes AX and AY of the swing unit 22 (light reflecting surface 12A) of the swing mirror 20.
  • the drive signal generation unit 31 generates drive signals DX and DY having the frequency adjusted (determined) by the drive frequency adjustment unit 33.
  • FIG. 3 is a schematic circuit diagram of the drive circuit 30.
  • the drive circuit 30 uses the oscillating mirror 20 as an oscillator (vibrator), and also feeds back the oscillating state of the oscillating mirror 20 to generate the drive signals DX and DY.
  • a circuit (resonance circuit) is formed.
  • the drive circuit 30 constitutes an RC resonance circuit.
  • the drive frequency adjusting unit 33 generates a signal having a predetermined frequency (for example, a target frequency) based on the detection signals EX and EY from the oscillating mirror 20, and this is used as the drive signal generating unit 31.
  • the drive signal generation unit 31 includes a phase shift circuit 31A that shifts the phase of the signal having the frequency and an amplifier 31B that amplifies the signal having the phase shifted.
  • the drive signal generator 31 supplies the amplified signal to the oscillating mirror 20 as drive signals DX and DY.
  • FIG. 4 is a diagram schematically showing the relationship between the drive signals DX and DY generated by the drive circuit 30, the change in the oscillation state of the light reflecting film 24 based on the drive signals DX, and the scanning trajectory of the scanning light L2. .
  • a scanning mode of the scanning region R0 by the optical scanning device SC will be described with reference to FIG.
  • the variable ⁇ 1 is set so that the drive signal DX is a sine wave having a frequency corresponding to the resonance frequency of the torsion bar TX, the swing frame SX, the torsion bar TY, and the swing plate SY of the swing mirror 20.
  • the variable ⁇ 2 is set so that the drive signal DY becomes a sine wave having a frequency corresponding to the resonance frequency of the torsion bar TY and the swing plate SY of the swing mirror 20.
  • the light reflecting film 24 (swing plate SY) resonates around the first swing axis AX and resonates around the second swing axis AY. Therefore, as shown in FIG. 4, when the scanning surface R1 of the scanning region R0 is viewed, the scanning light L2, which is the emitted light L1 reflected by the light reflecting film 24, has a trajectory (trajectory) TR that draws a Lissajous curve. (L2) is shown.
  • the optical scanning device SC has the oscillating mirror 20 that reflects the emitted light L1 and oscillates about the first and second oscillating axes AX and AY that are orthogonal to each other.
  • the scanning region R0 is scanned along the trajectory TR along the Lissajous curve.
  • FIG. 5 is a diagram showing a driving flow of the oscillating mirror 20 by the driving circuit 30.
  • the drive circuit 30 supplies the drive signal DX having the reference resonance frequency f0x and the drive signal DY having the reference resonance frequency f0y to the oscillating mirror 20 by the drive signal generation unit 31 (step S11).
  • the reference resonance frequencies f0x and f0y are, for example, designed resonance frequencies.
  • the resonance frequency determination unit 32 of the drive circuit 30 monitors the oscillating state by the detection signals EX and EY, and oscillates during the oscillation.
  • the oscillation frequency and resonance frequency of the mirror 20 are determined (step S12).
  • the drive frequency adjusting unit 33 detects a change in the resonance frequency of the oscillating mirror 20 (step S13).
  • the resonance frequency comparison unit 33A of the drive frequency adjustment unit 33 compares the resonance frequency every predetermined time (unit time), and changes the resonance frequency equal to or greater than a predetermined value (for example, the resonance frequency f0x changes to the resonance frequency f1x, That the resonance frequency f0y is changed to the resonance frequency f1y). Then, the resonance frequency comparison unit 33A detects a change in the ratio of the resonance frequencies (that is, f0x: f0y has changed to f1x: f1y).
  • the drive frequency adjusting unit 33 determines the target frequencies ftx and fty of the drive signals DX and DY so as to be the designed resonance frequency ratio (f0x: f0y) by the target frequency determining unit 33B (step S14). ). Then, the drive signal generation unit 31 adjusts the drive signals DX and DY so as to be the target frequencies ftx and fty determined by the drive frequency adjustment unit 33 (step S15). The drive circuit 30 operates so as to repeat steps S13 to S15.
  • FIGS. 6A and 6B are diagrams schematically showing the relationship between the change in the resonance frequency of the oscillating mirror 20 and the change in the drive frequencies fx and fy of the drive signals DX and DY based on the change.
  • the generation and adjustment operations of the drive signals DX and DY by the drive circuit 30 will be described with reference to FIGS. 6A and 6B.
  • the oscillating mirror 20 is designed so that the scanning light L2 follows a predetermined trajectory (for example, the trajectory TR in FIG. 4) when operated under predetermined conditions (environmental temperature, humidity, operating time, etc.).
  • a predetermined trajectory for example, the trajectory TR in FIG. 4
  • predetermined conditions environmental temperature, humidity, operating time, etc.
  • the oscillating mirror 20 resonates at the first reference resonance frequency f0x around the first oscillating axis AX, and the drive signal DX having the reference resonance frequency f0x is the largest when supplied. Swings with amplitude. Therefore, when the drive signal DX is the horizontal axis and the gain (level of the detection signal EX) that is the amplitude around the first swing axis AX of the swing mirror 20 is the vertical axis, the first swing of the swing mirror 20 is set.
  • the swing characteristic around the dynamic axis AX is as shown on the upper side of FIG. 6A.
  • the oscillating mirror 20 resonates at the second reference resonance frequency f0y around the second oscillating axis AY under the predetermined condition, and the drive signal DY having the reference resonance frequency f0y is supplied. Swings with the largest amplitude. Therefore, when the drive signal DY is the horizontal axis and the gain (level of the detection signal EY) that is the amplitude around the second swing axis AY of the swing mirror 20 is the vertical axis, the second swing of the swing mirror 20 is performed.
  • the swing characteristic around the dynamic axis AY is as shown in the lower side of FIG. 6A.
  • FIG. 6B is a diagram illustrating the swing characteristics around the first and second swing axes AX and AY of the swing mirror 20 when the swing characteristics are changed.
  • a curve indicating the same swing characteristic as in FIG. 6A is indicated by a broken line.
  • the resonance frequency of the oscillating mirror 20 is shifted in the direction of increasing. Accordingly, as shown in FIG. 6B, the resonance frequency around the first oscillation axis AX of the oscillation mirror 20 (hereinafter referred to as the first resonance frequency fnx) is changed from the first reference resonance frequency f0x to the frequency f1x. Then, it changes by the change amount x1.
  • the resonance frequency of the oscillating mirror 20 around the second oscillating axis AY (hereinafter referred to as the second resonance frequency fny) is changed by the amount of change y1 from the second reference resonance frequency f0y to the frequency f1y. Change.
  • the resonance frequencies fnx and fny of the oscillating mirror 20 and the changes thereof are based on, for example, the designed amplitude value of the oscillating mirror 20 and the change thereof, and the change of the amplitude value and the phase of the drive signals DX and DY. Can be determined by comparing.
  • the scanning region R0 is densely scanned by the Lissajous scan, even when the first and second resonance frequencies fnx and fny of the oscillating mirror 20 are changed, they are different from each other, and the ratio between the two is different. Is preferably approximately the same as the ratio of the reference resonance frequencies f0x and f0y (f0x: f0y, hereinafter referred to as the reference ratio). This is because the trajectory of the scanning light L2 overlaps and the same scanning point is suppressed from being scanned a plurality of times.
  • the amounts of change x1 and y1 of the first and second resonance frequencies fnx and fny are often not the same.
  • the oscillating part 22 of the oscillating mirror 20 is formed by processing a semiconductor substrate, its natural frequency changes at the same ratio as a whole.
  • the first and second resonance frequencies fnx and fny change from the first and second reference resonance frequencies f0x and f0y by a predetermined ratio, but the change amounts x1 and y1 are not the same. .
  • the change amount x1 of the first resonance frequency fnx is relatively small, and the change amount y1 of the second resonance frequency fny is relatively large.
  • the oscillating mirror 20 is oscillated at a ratio different from the reference ratio. Will move. Therefore, particularly when performing a Lissajous scan, the trajectory of the scanning light L2 may change greatly, and the scanning point and the distance measuring point may fluctuate.
  • the drive circuit 30 determines and monitors the first and second resonance frequencies fnx and fny around the first and second swing axes AX and AY of the swing mirror 20, respectively. Then, the drive frequencies fx and fy are adjusted so that the ratio of the first and second resonance frequencies fnx and fny becomes the reference ratio.
  • the drive frequency adjusting unit 33 adjusts the drive frequency fx of the drive signal DX, which is a drive signal having a low frequency, of the drive signals DX and DY, for example, from the resonance frequency f1x.
  • the drive frequencies fx and fy are adjusted so that the drive frequency fy of the drive signal DY, which is a drive signal having a high frequency, is increased by the amount x2, and is decreased by the adjustment amount y2 from the resonance frequency f1y.
  • the resonance frequency comparison unit 33A confirms that the first and second resonance frequencies fnx and fny of the oscillating mirror 20 are out of a predetermined range including a reference ratio (hereinafter referred to as a reference range). judge. Then, the target frequency determination unit 33B determines target frequencies ftx and fty that are targets for adjusting the drive frequencies fx and fy so that the ratio of the oscillation frequencies of the oscillation mirror 20 is within the reference range.
  • the drive signal generator 31 generates drive signals DX and DY having target frequencies ftx and fty and supplies them to the oscillating mirror 20.
  • the oscillating mirror 20 oscillates (oscillates) at a frequency slightly different from the resonance frequencies f1x and f1y.
  • the trajectory TR of the scanning light L2 reflected by the oscillating mirror 20 is stabilized. Therefore, the oscillating mirror 20 oscillates around the first and second oscillation axes AX and AY stably even under different conditions. Accordingly, it is possible to irradiate the scanning region R0 with the scanning light L2 in a stable orbit, and a stable scanning result can be obtained. Further, the distance measurement result based on the scanning result is also stabilized.
  • the drive circuit 30 determines and monitors each of the first and second resonance frequencies fnx and fny of the oscillating mirror 20, and the oscillating mirror 20 stabilizes following this. Then, the drive signals DX and DY that resonate are generated.
  • the drive circuit 30 compares the first and second resonance frequencies fnx and fny of the oscillating mirror 20, and the first and second resonance frequencies fnx and fny are changed based on a change in the ratio of the first and second resonance frequencies fnx and fny.
  • the drive frequency adjusting unit 33 performs the first and second drive when the ratio between the first and second resonance frequencies fnx and fny is within a predetermined range (reference ratio f0x: f0y).
  • the frequencies fx and fy of the first and second drive signals DX and DY are adjusted so that the frequencies fx and fy of the signals DX and DY become the first and second resonance frequencies fnx and fny, respectively.
  • the drive frequency adjusting unit 33 is configured such that when the ratio between the first and second resonance frequencies fnx and fny is out of a predetermined range (for example, when the ratio becomes f1x: f1y), The frequencies fx and fy of the first and second drive signals DX and DY are adjusted so that the frequencies fx and fy of the second drive signals DX and DY become frequencies ftx and fty different from the resonance frequencies fnx and fny. .
  • the oscillation mirror 20 has a ratio of the oscillation frequency within the reference range. Is maintained. Therefore, it is possible to provide the mirror device 12 in which the oscillating mirror 20 is stably oscillated, and the optical scanning device SC and the distance measuring device 10 including the mirror device 12.
  • the drive frequency adjusting unit 33 adjusts both the drive frequencies fx and fy has been described. However, considering that the ratio between the drive frequencies fx and fy falls within the reference range, only one of the drive frequencies fx and fy may be adjusted.
  • the drive frequency adjusting unit 33 sets the frequencies fx and fy of the first and second drive signals DX and DY to the first.
  • the frequencies fx and fy of the first and second drive signals DX and DY are adjusted so as to be the second resonance frequencies fnx and fny, and the ratio of the first and second resonance frequencies fnx and fny is within the predetermined range. If the frequency is out of the range, the frequency of the first and second drive signals DX and DY is adjusted so that one of the first and second drive signals DX and DY has a frequency different from the resonance frequency. Also good.
  • the drive frequency of a drive signal having a relatively high frequency (for example, the drive frequency fy of the drive signal DY) is lowered, and the drive frequency of a drive signal having a relatively low frequency (for example, drive)
  • the oscillating mirror 20 can be resonated without greatly deviating from the resonance frequency (resonance point) of both. That is, it is possible to stably resonate the oscillating mirror 20 while suppressing a decrease in the oscillation amplitude.
  • the drive circuit 30 adjusts the frequencies fx and fy of the drive signals DX and DY according to changes in the first and second resonance frequencies fnx and fny of the oscillating mirror 20 has been described.
  • the drive circuit 30 may generate the drive signals DX and DY so that the ratio between the first oscillation frequency and the second oscillation frequency of the oscillation mirror 20 is within the reference range.
  • the reference range that is the target range of the frequency fx of the drive signal DX and the frequency fy of the drive signal DY adjusted by the drive circuit 30 may be an absolute range or a relative range.
  • the reference range may vary based on the difference between the determined first and second resonance frequencies fnx and fny.
  • the case where the oscillating mirror 20 oscillates around the first and second oscillating axes AX and AY orthogonal to each other has been described.
  • the first and second swing axes AX and AY are not limited to being orthogonal to each other, and may be different from each other.
  • the mirror device 12 includes the oscillating mirror 20 that oscillates around the first and second oscillating shafts AX and AY that are different from each other, and the oscillating mirror 20 includes the first and second oscillating shafts, respectively.
  • a drive circuit 30 that generates first and second drive signals DX and DY for swinging around AX and AY. Further, the drive circuit 30 determines first and second oscillation frequencies around the first and second oscillation axes AX and AY of the oscillation mirror 20 based on the oscillation state of the oscillation mirror 20, respectively.
  • the first and second drive signals DX and DY are generated so that the ratio between the first oscillation frequency and the second oscillation frequency is within a predetermined range. Therefore, it is possible to provide the mirror device 12 having the oscillating mirror 20 that oscillates around the two oscillating axes AX and AY.
  • the mirror device 12 can operate as a mirror other than the optical scanning device SC.
  • the optical scanning device SC can be used for purposes other than distance measurement.
  • the present invention can be implemented as, for example, the mirror device 12, and can also be implemented as the optical scanning device SC or the distance measuring device 10.
  • the mirror device 12 is mounted on a scanning device that performs Lissajous scanning, such as the optical scanning device SC and the distance measuring device 10, or a distance measuring device including the same, so that the scanning trajectory is stabilized and has a great effect. Can be obtained.
  • the present invention can also be implemented as a method for stably oscillating the oscillating mirror 20, for example, by performing the steps shown in FIG. That is, for example, in the method according to the present invention, the first and second drive signals DX and DY are supplied, and the oscillating mirror 20 is moved around the first and second oscillating axes AX and AY which are different from each other. Based on the swinging step S11 and the swinging state of the swinging mirror 20, first and second swinging frequencies around the first and second swinging axes AX and AY of the swinging mirror 20 are determined.
  • the present invention can also be implemented, for example, by installing a program that causes a computer to function as the drive circuit 30 and connecting the computer to the oscillating mirror 20. That is, the program according to the present invention, for example, causes the computer to send the first and second drive signals DX and DY to the oscillating mirror 20 that oscillates around the first and second oscillating axes AX and AY that are different from each other.
  • the first and second oscillation frequencies around the first and second oscillation axes AX and AY of the oscillation mirror 20 are determined based on the oscillation state of the oscillation mirror 20, respectively.
  • the drive circuit 30 is configured to adjust the frequencies fx and fy of the first and second drive signals DX and DY so that the ratio between the swing frequency of the first drive signal and the second swing frequency falls within a predetermined range. Accordingly, it is possible to provide a program for stably driving the oscillating mirror 20 that oscillates around the two oscillating axes AX and AY.

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

Abstract

Selon la présente invention, ce dispositif de miroir comprend un miroir oscillant qui oscille autour du premier et second axes mutuellement différents, et un circuit de commande qui génère des premier et second signaux de commande destinés à faire pivoter le miroir oscillant autour des premier et second axes. Le circuit de commande détermine les fréquences d'oscillation autour des premier et second axes du miroir oscillant sur la base de l'état d'oscillation du miroir oscillant, et génère les premier et second signaux de commande de telle sorte que le rapport entre la première fréquence d'oscillation et la seconde fréquence d'oscillation du miroir oscillant se trouve dans une plage prédéterminée.
PCT/JP2019/006051 2018-02-20 2019-02-19 Dispositif miroir, dispositif de balayage optique, dispositif de mesure de distance, procédé de commande destiné à un dispositif miroir et programme WO2019163754A1 (fr)

Applications Claiming Priority (2)

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JP2018027788 2018-02-20
JP2018-027788 2018-02-20

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WO2019163754A1 true WO2019163754A1 (fr) 2019-08-29

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4099082A1 (fr) * 2021-06-01 2022-12-07 FUJIFILM Corporation Dispositif de balayage optique, procédé de commande d'un dispositif de balayage optique et système de dessin d'image

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110267501A1 (en) * 2010-04-28 2011-11-03 Microsoft Corporation Scanned beam display and image capture
JP2013003253A (ja) * 2011-06-14 2013-01-07 Nippon Signal Co Ltd:The 光走査装置
JP2016156913A (ja) * 2015-02-24 2016-09-01 日本信号株式会社 光走査装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110267501A1 (en) * 2010-04-28 2011-11-03 Microsoft Corporation Scanned beam display and image capture
JP2013003253A (ja) * 2011-06-14 2013-01-07 Nippon Signal Co Ltd:The 光走査装置
JP2016156913A (ja) * 2015-02-24 2016-09-01 日本信号株式会社 光走査装置

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4099082A1 (fr) * 2021-06-01 2022-12-07 FUJIFILM Corporation Dispositif de balayage optique, procédé de commande d'un dispositif de balayage optique et système de dessin d'image
JP7612521B2 (ja) 2021-06-01 2025-01-14 富士フイルム株式会社 光走査装置、光走査装置の駆動方法、及び画像描画システム

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