WO2018225496A1 - Dispositif de mesure de distance et dispositif de mesure de forme tridimensionnelle - Google Patents

Dispositif de mesure de distance et dispositif de mesure de forme tridimensionnelle Download PDF

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Publication number
WO2018225496A1
WO2018225496A1 PCT/JP2018/019625 JP2018019625W WO2018225496A1 WO 2018225496 A1 WO2018225496 A1 WO 2018225496A1 JP 2018019625 W JP2018019625 W JP 2018019625W WO 2018225496 A1 WO2018225496 A1 WO 2018225496A1
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Prior art keywords
light
measurement
optical path
switching element
path switching
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PCT/JP2018/019625
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English (en)
Japanese (ja)
Inventor
渡辺　正浩
達雄 針山
敦史 谷口
兼治 丸野
Original Assignee
株式会社日立製作所
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Priority claimed from JP2018046769A external-priority patent/JP6513846B2/ja
Application filed by 株式会社日立製作所 filed Critical 株式会社日立製作所
Priority to CA3053315A priority Critical patent/CA3053315C/fr
Priority to US16/484,844 priority patent/US10900773B2/en
Publication of WO2018225496A1 publication Critical patent/WO2018225496A1/fr

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
    • 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

Definitions

  • the present invention relates to a distance measuring device and a three-dimensional shape measuring device.
  • the present invention claims priority of Japanese patent application number 2017-111271 filed on June 6, 2017, and Japanese patent application number 2018-046769 filed on March 14, 2018. For designated countries where weaving by reference is allowed, the content described in that application is incorporated into this application by reference.
  • Patent Document 1 discloses a technique related to an optical measuring instrument.
  • Paragraph [0034] of the same document states that “in the housing portion 34, a rod-shaped shaft (support member) 36 that is fixedly and integrally provided in the housing portion 34, and is movable around the shaft 36”.
  • a reflection mirror 37 held by a shaft 36 and a holding member 35 for holding the reflection mirror 37 at a predetermined position before and after rotation are disposed.
  • the shaft 36, the reflection mirror 37 and the holding member 35 are provided with a light source 38.
  • the direction control unit is configured to change the traveling direction of the measurement light output from the head to a predetermined direction (for example, 90 degrees).
  • the paragraph [0035] states that “the holding member 35 is in the first position where the measurement light from the light source 38 is not reflected before the reflection mirror 37 rotates about the shaft 36.
  • the holding member 35 is a position where the reflection mirror 37 rotates a predetermined angle (for example, 45 degrees) about the axis 36 to change the traveling direction of the measurement light from the light source 38 to a predetermined direction (90 degrees).
  • the reflecting mirror 37 functions to be held in the second position after moving to the second position, which is described in the paragraph [0036].
  • the traveling direction of the measuring light from the light source 38 is not changed, and in the second position, the traveling direction of the measuring light from the light source 38 is changed to a predetermined direction. Yes.
  • the present invention has been made in view of the above points, and an object of the present invention is to provide a technique capable of realizing downsizing of a measuring unit in a distance measuring device.
  • the present application includes a plurality of means for solving at least a part of the above-described problems, and examples thereof are as follows.
  • a distance measuring device includes a light emitting unit that outputs measurement light, a polarization state control unit that controls polarization of measurement light output from the light emitting unit, and the polarization
  • An optical path switching element that selectively emits the measurement light controlled by the state control unit, and the polarization state control unit is configured to emit the measurement light from the optical path switching element in a plurality of directions.
  • the optical path switching element is reflected light used for measuring a distance to an object, and takes in the reflected light with respect to the object of the measurement light emitted from the optical path switching element.
  • FIG. 1 is a schematic diagram illustrating an example of a distance measuring device 10 according to the first embodiment.
  • the distance measuring device 10 according to the present embodiment includes a distance measuring control mechanism 110, a connection cable 150, and a measuring probe 160.
  • the distance measurement control mechanism 110 will be described in detail later, but measurement light is output to the measurement probe 160.
  • the connection cable 150 has an optical fiber and guides the measurement light to the measurement probe 160.
  • the measurement probe 160 is a device that irradiates the object T with measurement light and guides reflected light from the object T to the distance measurement control mechanism 110.
  • the measurement probe 160 includes a lens system 161, a rotation mechanism 162, an optical path switching element 163, a measurement probe tip 164, a polarization state control unit 165, and a polarization state control unit driving device 166.
  • the lens system 161 stops the measurement light output from the distance measurement control mechanism 110 and guided to the connection cable 150 and guides it to the polarization state control unit 165.
  • the rotation mechanism 162 rotates the optical path switching element 163 around a rotation axis parallel to the measurement light output from the lens system 161 by using a driving device such as a motor under the control of a distance calculation unit described later.
  • the optical path switching element 163 selectively emits light using the measurement light controlled by the polarization state control unit 165.
  • the optical path switching element 163 has an optical path switching function, and a first direction 300a that is the same traveling direction as the traveling direction of the measurement light output from the lens system 161 and a second direction that is substantially orthogonal to the first direction 300a. The light is emitted toward at least one of the direction 300b.
  • the optical path switching element 163 selectively emits light according to a change in the polarization direction, for example.
  • the optical path switching element 163 is, for example, a polarization beam splitter.
  • the measurement probe tip 164 engages the optical path switching element 163 and allows light emitted from the optical path switching element 163 to pass therethrough.
  • the measurement probe tip 164 is, for example, a cylindrical shape having an opening in the lower part (first direction 300a) shown in FIG. 1, is made of a material that transmits light, and the optical path switching element 163 is formed at least at a part of the inner wall. Locked.
  • the measurement probe tip 164 rotates around a rotation axis parallel to the measurement light output from the lens system 161, and the optical path switching element 163 rotates with the rotation of the measurement probe tip 164.
  • the configuration of the measurement probe tip 164 is not limited to this.
  • the optical path switching element 163 may be locked by one or a plurality of pillars, and the optical path switching element 163 may rotate as the pillars are driven.
  • the measurement probe tip 164 may be formed of, for example, a transparent two-layer cylinder, and the optical path switching element 163 may be locked by the inner cylinder and the optical path switching element 163 may be rotated.
  • the polarization state control unit 165 controls the polarization of the measurement light output from the distance measurement control mechanism 110 under the control of the distance calculation unit. For example, the polarization state control unit 165 changes the polarization direction of the measurement light.
  • the polarization state control unit driving device 166 drives the polarization state control unit 165 so that the polarization state control unit 165 changes the polarization of the measurement light.
  • the polarization state control unit 165 and the polarization state control unit driving device 166 will be described later.
  • the measurement light output from the ranging control mechanism 110 reaches the polarization state control unit 165 via the connection cable 150 and the lens system 161, and the polarization state is controlled by the polarization state control unit 165.
  • the measurement light controlled by the polarization state control unit 165 reaches the optical path switching element 163.
  • the light emitted from the optical path switching element 163 in the first direction 300 a reaches the object T from the opening of the measurement probe tip 164.
  • the light reflected or scattered by the object T travels in the reverse direction of the emitted light in the order of the optical path switching element 163, the polarization state control unit 165, the lens system 161, and the connection cable 150, and enters the distance measurement control mechanism 110.
  • the distance measurement control mechanism 110 converts the arrived measurement light into an electrical signal and transmits it to a distance calculation unit (not shown).
  • the distance calculation unit calculates the distance to the object T.
  • the bottom depth of the cylindrical shape can be measured by using the measurement light emitted in the first direction 300a.
  • the light emitted from the optical path switching element 163 in the second direction 300b rotates according to the rotation of the optical path switching element 163, passes through the opening or the wall surface of the side surface of the measurement probe tip 164, and passes through the object T. Is irradiated.
  • the light reflected or scattered by the target T travels back along the emitted path in the same manner as the light emitted in the first direction 300a and reaches the distance measurement control mechanism 110, and the distance to the target T is calculated.
  • the measurement light emitted in the second direction 300b for example, the shape of a cylindrical side surface can be measured.
  • FIG. 2 is a diagram for explaining the operation of the optical path switching element 163.
  • FIGS. 2A1 and 2A2 illustrate an example in which a polarizing beam splitter 180 is used as the optical path switching element 163.
  • FIG. 2 (A1) the measurement light is polarized in the left-right direction of FIG. 2, and in FIG. 2 (A2), the measurement light is polarized in the depth direction of FIG. 2 (the back side and the front side). It shows the state.
  • the incident measurement light is transmitted through the prism of the polarization beam splitter 180 and is the same as the incident measurement light. Proceed in direction 300a. The light reflected by the object T travels the same path and reaches the distance measurement control mechanism 110.
  • the incident measurement light is reflected by the prism and is substantially orthogonal to the measurement light. 2 direction 300b. Similar to the light traveling in the first direction 300a, the light reflected by the object T travels the same path and reaches the distance measurement control mechanism 110.
  • the traveling direction of the measurement light is maintained in the first direction 300a or the second direction 300b. It becomes possible to do. That is, by controlling the polarization of the measurement light by the polarization state control unit 165, the traveling direction of the measurement light can be switched to the first direction 300a or the second direction 300b.
  • a 1 ⁇ 2 wavelength plate is used as the polarization state control unit 165. If the polarization direction of linearly polarized light incident on the half-wave plate is ⁇ and the direction of the principal axis of the half-wave plate is ⁇ , the polarization direction of the emitted light is 2 ⁇ .
  • FIG. 12 is a diagram illustrating the absolute angle relationship of each optical element in the first embodiment.
  • the half-wave plate 305 is used as the polarization state control unit 165, and the polarization beam splitter 180 is used as the optical path switching element 163. If the angle of the vibration direction of the linearly polarized light incident on the half-wave plate 305 is ⁇ and the direction of the principal axis of the half-wave plate 305 is ⁇ , the angle of the vibration direction of the emitted linearly polarized light is 2 ⁇ .
  • angles ⁇ and ⁇ , and an angle ⁇ are absolute rotation angles with reference to a coordinate axis x orthogonal to the first direction 300a (parallel to the coordinate axis z).
  • An angle in a direction in which the polarization beam splitter 180 rotated by the rotation mechanism 162 reflects light is ⁇ .
  • FIG. 12A is a diagram for explaining a relative angle relationship of each optical element in the first embodiment.
  • the relationship between the vibration direction angle of the measurement light, the angle of the principal axis of the half-wave plate, and the relative angle of the optical path switching element 163 will be described.
  • the half-wave plate 305 is used as the polarization state control unit 165, and the polarization beam splitter 180 is used as the optical path switching element 163.
  • the polarization beam splitter 180 transmits linearly polarized light having a vibration direction parallel to the incident surface 309 (that is, emits in the direction of the first direction 300a) and has a vibration direction that forms an angle of ⁇ / 2 with respect to the incident surface 309.
  • the linearly polarized light is reflected (ie, emitted in the direction of the second direction 300b).
  • the half-wave plate 305 tilts and emits the vibration direction of the linearly polarized light by twice the angle that the vibration direction of the incident linearly polarized light forms with the main axis of the half-wave plate 305.
  • the incident surface 309 has an inclination of a relative angle ⁇ with respect to the first measurement light vibration direction 306 a incident on the half-wave plate 305.
  • the main measurement axis 308 of the half-wave plate 305 is incident on the half-wave plate 305.
  • the measurement light vibration direction 307 emitted from the half-wave plate 305 is parallel to the incident surface 309. Try to keep. Further, as shown in FIG. 13A, when the measurement light is irradiated in the first direction 300a, the main measurement axis 308 of the half-wave plate 305 is incident on the half-wave plate 305.
  • the measurement light vibration direction 307 emitted from the half-wave plate 305 is parallel to the incident surface 309. Try to keep. Further, as shown in FIG.
  • the polarization state control unit 165 can be controlled by rotating the half-wave plate 305 by the polarization state control unit driving device 166.
  • a liquid crystal element can be used for the polarization state control unit 165.
  • the polarization state control unit 165 can change the polarization direction of the output measurement light.
  • measurement light having a polarization component of random polarization or circular polarization is emitted from the lens system 161, a polarizing plate is used for the polarization state control unit 165, and the polarizing plate is rotated by the polarization state control unit driving device 166.
  • the polarization direction of the measurement light may be controlled.
  • the direction of the main axis of the polarizing plate is ⁇
  • the direction of the light emitted from the optical path switching element 163 can be switched to the first direction 300a or the second direction 300b.
  • a fiber-type polarization control element can be used for the polarization state control unit 165.
  • the polarization direction of the measurement light output from the polarization state control unit 165 can be controlled by inducing birefringence.
  • FIGS. 2B1 and 2B2 show an example in which a combination of a birefringent plate 181 and a mirror 182 is used for the optical path switching element 163.
  • FIG. 2B1 shows a state in which the measurement light is polarized in the depth direction of FIG. 2
  • FIG. 2B2 shows a state in which the measurement light is polarized in the left-right direction in FIG.
  • the birefringent plate 181 has a property of shifting the optical path according to the polarization state of the measurement light. For example, as shown in FIG. 2 (B1) and FIG. 2 (B2), the birefringence is such that the measurement light polarized in the depth direction in FIG. 2 goes straight and the optical path of the measurement light polarized in the left-right direction in FIG. 2 is shifted. A plate 181 is installed. In addition, by arranging the mirror 182 on the optical path shifted by the birefringent plate 181, the emission direction of the shifted measurement light is changed.
  • the first direction 300a having the same optical axis as the measurement light emitted from the lens system 161, or the first direction 300a Light can be selectively emitted in the second direction 300b having different optical axes.
  • the emission direction is opposite to that of the emission direction.
  • the measurement probe tip 164 can be downsized. For example, compared to a case where a mirror is installed at the measurement probe tip 164 and the direction of emission of the measurement light is made different by driving the mirror, a space for driving the mirror in the measurement probe tip 164 is not required and efficient. It is possible to configure locations used for measurement.
  • FIG. 3 is a diagram illustrating an example of the configuration of the distance measurement control mechanism 110 according to the first embodiment.
  • the distance measurement control mechanism 110 shown in FIG. 3 measures the distance from the object T using FMCW (Frequency Modulated Continuous Waves) or SS-OCT (Swept-Source Optical Coherence Tomography) (or wavelength sweep OCT).
  • FMCW Frequency Modulated Continuous Waves
  • SS-OCT Spept-Source Optical Coherence Tomography
  • OCT wavelength sweep
  • the distance measurement control mechanism 110 shown in FIG. 3 is connected to the control device 210 and the display device 220 in addition to the measurement probe 160 described above.
  • the control device 210 includes a distance calculation unit that calculates the distance from the object T using the information received from the distance measurement control mechanism 110.
  • the display device 220 outputs the measurement result.
  • the distance calculation unit 110 may be included in the distance calculation unit.
  • the control device 210 may be connected to the measurement probe 160 so as to be directly communicable.
  • the ranging control mechanism 110 includes a laser light source 101, an oscillator 102, optical fiber couplers 103, 104, 106, 114, an optical fiber 105, light receivers 107, 109, a circulator 108, a reference mirror 112,
  • the optical switches 113a and 113b and the distance measurement control mechanism control unit 111 are provided.
  • the ranging control mechanism control unit 111 transmits a sweep waveform signal to the oscillator 102.
  • the oscillator 102 injects a triangular wave current into the laser light source 101 to modulate the drive current.
  • the laser light source 101 generates FM (Frequency-Modulated) light that is temporally swept at a constant modulation speed.
  • the laser light source 101 may be configured as a semiconductor laser device with an external resonator, and the resonance wavelength of the laser light source 101 may be changed by a triangular wave control signal from the oscillator 102. As a result, FM light whose frequency is swept in time from the laser light source 101 is generated.
  • the generated FM light is divided by the optical fiber coupler 103.
  • the optical fiber couplers 103, 104, and 114 may be beam splitters. One of the divided lights is guided to the reference optical system and further divided by the optical fiber coupler 104.
  • the divided light After the divided light is provided with a certain optical path difference by the optical fiber 105, it is combined by the optical fiber coupler 106 and received by the light receiver 107.
  • This is a structure of a Mach-Zehnder interferometer, and a constant beat signal proportional to the optical path difference is generated in the light receiver 107.
  • the other of the lights divided by the optical fiber coupler 103 passes through the circulator 108 and is branched by the optical fiber coupler 114, one of which is reflected by the reference mirror 112 and becomes reference light, and the other is sent from the measurement probe 160 to the object T. Irradiated.
  • the distance measurement control mechanism 110 shown in FIG. 3 has optical switches 113a and 113b, which will be described later.
  • the light reflected on the object T returns to the distance measurement control mechanism 110 via the connection cable 150.
  • the returned measurement light passes through the optical switches 113 a and 113 b, merges with the reference light reflected by the reference mirror 112 by the optical fiber coupler 114, and is guided to the light receiver 109 by the circulator 108.
  • a beat signal generated by the interference between the reference light and the measurement light is detected.
  • the ranging control mechanism control unit 111 performs A / D conversion of the measurement beat signal received by the light receiver 109 using the reference beat signal received by the light receiver 107 as a sampling clock. Alternatively, the reference beat signal and the measurement beat signal are sampled with a constant sampling clock.
  • the reference beat signal can generate a signal that is 90 degrees out of phase by performing Hilbert transform. Since the local phase of the signal can be obtained from the reference signal before and after the Hilbert transform, the timing at which the reference signal becomes a constant phase can be obtained by interpolating this phase.
  • the distance L to the measurement object is half of the distance traveled by light during ⁇ t, it can be calculated as follows using the light velocity c in the atmosphere.
  • the measurement signal obtained in the ranging control mechanism control unit 111 is subjected to FFT (First Fourier Transform: Fast Fourier Transform) to obtain the peak position and size, it corresponds to the reflection position and the reflected light amount of the object T, respectively.
  • FFT First Fourier Transform: Fast Fourier Transform
  • the FFT amplitude spectrum can be used as it is.
  • interpolation as shown in FIG. 4 is performed to increase the distance detection resolution.
  • FIG. 4 is a diagram showing an example of a method for obtaining the reflection position on the surface of the object to be measured from the reflection intensity profile. If the horizontal axis in this figure is the FFT frequency axis and the vertical axis is the reflection intensity, the vicinity of the peak is discrete data as shown in this figure.
  • the optical switches 113a and 113b will be described.
  • the difference between the optical path length from the optical fiber coupler 114 to the reference mirror 112 and the optical path length from the optical fiber coupler 114 to the object T is determined by the laser light source 101. Must be less than the coherence distance.
  • the optical switch 113a and the optical switch 113b are simultaneously switched according to the distance from the optical fiber coupler 114 to the object T, and the length of the optical fiber between the switches is changed.
  • the beat frequency also increases when the difference between the optical path length from the optical fiber coupler 114 to the reference mirror 112 and the optical path length from the optical fiber coupler 114 to the object T is too long, that is, when the coherence distance is long.
  • the light receiver 109 cannot detect the light. Therefore, the optical switch 113a and the optical switch 113b are simultaneously switched so that the beat frequency becomes a frequency that can be detected by the light receiver 109, and the length of the optical fiber between the switches is changed.
  • the number of optical fibers to be switched is two. However, the length may be switched by installing three or more optical fibers according to the range to be measured. Further, the switching timing may be constant or may be changed according to the situation such as the distance of the object T from the optical path switching element 163. For example, the optical switch 113a and the optical switch 113b may be switched every rotation in synchronization with the rotation of the optical path switching element 163.
  • optical path is described as using an optical fiber, it is assumed that the light propagates in free space once using an optical fiber collimator, etc., and the optical path length is changed by switching the light with a mirror or moving the mirror. May be changed.
  • optical switches 113a and 113b may be provided in the optical path between the optical fiber coupler 114 used for branching and the reference mirror 112, and the length of the optical fiber between the optical switches 113a and 113b may be switched in the same manner.
  • the optical switches 113a and 113b are controlled to be switched by the distance measurement control mechanism control unit 111.
  • the optical path from the optical fiber coupler 114 to the optical switch 113 b is installed in the distance measurement control mechanism 110.
  • these optical paths may be installed in the measurement probe 160 instead of the distance measurement control mechanism 110.
  • the distance measurement method performed using the distance measurement control mechanism 110 is not limited to the above example.
  • a method of irradiating an object T with a pulse or burst-like light and measuring the time until the pulse or burst is received a phase / shift method, or an optical comb as in the TOF (Time Of Flight) method
  • a method of measuring the phase of the received signal by irradiating the object T with light whose intensity is continuously modulated as in the distance measuring method can be used.
  • the distance may be measured by measuring the defocus, and the white confocal method, the astigmatism method, the knife edge method, and the conoscopic holography method may be used.
  • FIG. 5 is a diagram illustrating another example of the configuration of the distance measurement control mechanism 110 according to the first embodiment.
  • the distance measurement control mechanism 110 shown in FIG. 5 is a configuration example using SD-OCT (Spectral Domain-Optical Coherence Tomography) (or frequency domain OCT) as a principle of distance measurement.
  • the distance measurement control mechanism 110 includes a circulator 108, an optical fiber coupler 114, a reference mirror 112, a distance measurement control mechanism control unit 111, a broadband light source 115, and a spectroscope 116.
  • the measurement light generated by the broadband light source 115 reaches the circulator 108 via the optical fiber.
  • the measurement light derived from the circulator 108 is divided by the optical fiber coupler 114, and a part of the divided measurement light is emitted to the object T via the measurement probe 160.
  • a part of the divided measurement light is reflected to the reference mirror 112 as reference light.
  • the measurement light reflected by the object T returns to the distance measurement control mechanism 110 via the measurement probe 160, and the reflected light reflected by the reference mirror 112 is merged by the optical fiber coupler 114, and the spectroscope 116 is obtained via the circulator 108. Is detected.
  • the spectrum of the detected light shows a vibration having a frequency proportional to the difference in optical path length between the object T and the reference mirror 112, where the horizontal axis represents the wave number of light and the vertical axis represents intensity. Therefore, the distance measurement control mechanism control unit 111 shown in this figure realizes distance measurement by analyzing this frequency.
  • the distance measurement control mechanism 110 can employ a configuration using a white confocal method for distance measurement.
  • the distance measurement control mechanism 110 does not include the reference mirror 112 and the optical fiber coupler 114 shown in FIG. 5, and is configured so that chromatic aberration is intentionally generated in the lens system 161 instead.
  • a measurement probe 160 whose focal position varies depending on the wavelength of the measurement light is used.
  • the detected spectrum data itself can be obtained as data shown in FIG. 4 without performing FFT.
  • FIG. 6 is a schematic diagram showing an example of the three-dimensional shape measuring apparatus 20.
  • the three-dimensional shape measuring apparatus 20 in the present embodiment measures the three-dimensional shape of the object T using the function of the distance measuring apparatus 10.
  • the three-dimensional shape measuring apparatus 20 has a moving mechanism.
  • the moving mechanism includes an XZ axis moving mechanism 251 and a Y axis moving mechanism 252.
  • a measurement probe 160 is installed in the XZ axis moving mechanism 251.
  • the distance measuring device 10 having the measuring probe 160 is installed.
  • the XZ axis moving mechanism 251 moves in the X axis direction (left and right direction shown in FIG. 6) and the Z axis direction (up and down direction shown in FIG. 6).
  • the XZ axis movement mechanism 251 supports the measurement probe 160, and the measurement probe tip 164 moves as the XZ axis movement mechanism 251 moves.
  • the Y-axis moving mechanism 252 is a portal structure and moves in the Y-axis direction (the depth direction shown in FIG. 6).
  • the Y-axis moving mechanism 252 supports the XZ-axis moving mechanism 251, and the measurement probe tip 164 instructed by the XZ-axis moving mechanism 251 moves as the Y-axis moving mechanism 252 moves.
  • the configuration of the moving mechanism is not limited to this, and any method can be used as long as it moves the measurement probe tip 164 in three axial directions.
  • the distance measurement control mechanism 110 may not be installed in the XZ axis movement mechanism 251 but only the measurement probe 160 may be installed in the XZ axis movement mechanism 251 to move the measurement probe tip 164 in the three-axis direction.
  • the three-dimensional shape measuring apparatus 20 in the present embodiment has a general shaft configuration used in a three-dimensional measuring instrument, but the measuring probe of the distance measuring apparatus 10 in the present embodiment instead of the probe of the three-dimensional measuring instrument. By installing 160, it is possible to realize highly functional non-contact shape measurement.
  • the Z-axis is often provided on the tool side, and the X-axis and Y-axis are provided on the object T side, and the configuration is different from the configuration of the three-dimensional shape measuring apparatus 20 shown in FIG. .
  • the measurement probe 160 according to the present embodiment in the three-axis processing machine, it is possible to realize on-machine measurement on the processing machine.
  • the three-dimensional shape measurement apparatus 20 that enables measurement with a higher degree of freedom can be configured. it can.
  • FIG. 7 is a schematic diagram showing another example of the three-dimensional shape measuring apparatus 20. Differences from the three-dimensional shape measuring apparatus 20 shown in FIG. 6 will be described. 7 includes a rotation mechanism 256 in addition to the XZ axis movement mechanism 251 and the Y axis movement mechanism 252. The rotation mechanism 256 is locked by the rotation shaft 253 supported by the structure 254 and rotates around the rotation shaft 253. The rotating mechanism 256 is a rotating shaft (not shown) orthogonal to the rotating shaft 253 and rotates around a rotating shaft extending in the Z-axis direction shown in FIG.
  • a sample stage 255 is installed in the rotation mechanism 256, and the sample stage 255 rotates as the rotation mechanism 256 rotates. Thereby, the target T installed on the sample stage 255 moves. With this configuration, the posture of the object T with two degrees of freedom can be controlled.
  • the three-dimensional shape measuring apparatus 20 shown in FIG. 7 can not only control the three degrees of freedom of the relative position between the measurement probe 160 and the object T using the XZ axis moving mechanism 251 and the Y axis moving mechanism 252 but also rotate.
  • the mechanism 256 can be used to control two degrees of freedom of the relative position, and a total of five degrees of freedom can be controlled. Thereby, every part of the target T can be measured from every direction.
  • the three-dimensional shape measuring apparatus 20 in the present embodiment is not limited to the configuration shown in FIGS. 6 and 7.
  • FIG. 8 is a diagram illustrating an example of functional blocks of the three-dimensional shape measuring apparatus 20.
  • the three-dimensional shape measurement apparatus 20 includes a calculation unit 260, a distance measurement control mechanism 110, a measurement probe 160, a display unit 280, and a movement mechanism 250.
  • the distance measurement control mechanism 110 and the measurement probe 160 are the same as in the above-described example.
  • the calculation unit 260 performs overall control of the entire three-dimensional shape measurement process using a calculation device such as a CPU (Central Processing Unit) (not shown).
  • the display unit 280 is a device that outputs measurement results, and has the same function as the display device 220 described above.
  • the calculation unit 260 includes a distance calculation unit 261, a shape calculation unit 262, and a movement mechanism control unit 263.
  • the distance calculation unit 261 analyzes the measurement beat signal and the reference beat signal captured by the distance measurement control mechanism 110 and converts them into a distance.
  • the distance calculation unit 261 controls the measurement probe 160 to control the rotation angle of the measurement probe tip 164 and the polarization state of polarized light synchronized with the rotation.
  • the shape calculation unit 262 measures the shape of the object T using the data notified by the distance calculation unit 261.
  • the data notified by the distance calculation unit 261 includes data on the detection direction of the measurement light.
  • Information measured by the shape calculation unit 262 is output via the display unit 280.
  • the moving mechanism control unit 263 controls the moving mechanism 250 to control the relative position between the measurement probe 160 and the object T.
  • the distance calculation unit 261 is notified of the position and orientation of the target T controlled by the movement mechanism control unit 263.
  • the calculation unit 260 may be installed in the distance measurement control mechanism 110 or the measurement probe 160.
  • FIG. 9 is a schematic diagram illustrating an example of the distance measuring device 30 according to the second embodiment.
  • the distance measuring device 30 in the present embodiment is different from the distance measuring device 10 in the first embodiment in that it does not include the polarization state control unit driving device 166 and the polarization state control unit 165.
  • the distance measuring device 30 in the present embodiment switches the emission direction of the measurement light by using the wavelength instead of the polarization state of the measurement light.
  • the measurement light emitted from the distance measurement control mechanism 110 is introduced into the optical path switching element 163 via the lens system 161.
  • FIG. 2 (C1) and FIG. 2 (C2) are diagrams for explaining the operation of the optical path switching element 163 in the second embodiment.
  • FIGS. 2C1 and 2C2 illustrate an example in which a dichroic mirror 183 is used for the optical path switching element 163.
  • the dichroic mirror 183 may be a dichroic prism.
  • the dichroic mirror and the dichroic prism reflect light having a wavelength longer than the boundary at a certain wavelength and transmit light having a shorter wavelength. Alternatively, light having a shorter wavelength than the boundary is reflected and light having a longer wavelength is transmitted.
  • FIG. 2 (C1) shows a state in which the measurement light is transmitted. The measurement light travels in the first direction 300a.
  • FIG. 2 (C2) shows a state in which the measurement light is reflected.
  • the measurement light travels in the second direction 300b substantially orthogonal to the measurement light. That is, by using the dichroic mirror 183 for the optical path switching element 163, it is possible to emit measurement light in different directions.
  • the optical path switching element 163 in the present embodiment takes in the light reflected by the object T and guides it to the distance measurement control mechanism 110 by going back the emission path.
  • FIG. 10 is a diagram illustrating an example of the configuration of the distance measurement control mechanism 110 according to the second embodiment.
  • the distance measurement control mechanism 110 in this aspect includes an optical fiber coupler 103, 104, 106, 114, an optical fiber 105, a light receiver 107, 109, a circulator 108, a reference mirror 112, optical switches 113a, 113b,
  • laser light sources 101a and 101b, oscillators 102a and 102b, and an optical fiber switch 191 are provided.
  • the laser light source 101a and the laser light source 101b have different wavelengths.
  • the oscillator 102a oscillates the laser light source 101a
  • the oscillator 102b oscillates the laser light source 101b. Note that the laser light source 101 a and the laser light source 101 b may be oscillated by one oscillator 102.
  • the light emitted from the oscillator 102a and the oscillator 102b is selectively controlled by the optical fiber switch 191.
  • the optical fiber switch 191 is controlled by the distance measurement control mechanism control unit 111.
  • an element that combines light of different wavelengths into one optical fiber may be used.
  • a so-called WDM (Wavelength Division Multiplexing) coupler can be used.
  • the wavelength of the measurement light can be selected by causing the distance measurement control mechanism control unit 111 to select light from the laser light source 101a or light from the laser light source 101b.
  • the distance measurement control mechanism 110 of this aspect By using the distance measurement control mechanism 110 of this aspect, light having different wavelengths can be selectively incident on the optical path switching element 163. As a result, measurement light is selectively emitted from the optical path switching element 163 in the first direction 300a or the second direction 300b.
  • FIG. 11 is a diagram illustrating another example of the configuration of the distance measurement control mechanism 110 according to the second embodiment.
  • the distance measurement control mechanism 110 in this aspect includes two types of OCT / FMCW light generation / detection units 171a and 171b.
  • the OCT / FMCW light generation / detection units 171a and 171b include a laser light source 101, an oscillator 102, optical fiber couplers 103, 104, and 106, an optical fiber 105, light receivers 107 and 109, and a circulator 108, respectively. And have.
  • the laser diodes of the OCT / FMCW light generation / detection unit 171a and the OCT / FMCW light generation / detection unit 171b have different wavelength ranges.
  • the distance measurement control mechanism 110 in this aspect includes a WDM coupler 192.
  • the WDM coupler 192 joins the light emitted from the OCT / FMCW light generation / detection unit 171 a and the OCT / FMCW light generation / detection unit 171 b and causes the light to enter the optical fiber coupler 114.
  • This configuration generates measurement light in two different wavelength ranges at the same time.
  • measurement light is emitted simultaneously from the optical path switching element 163 in the first direction 300a and the second direction 300b.
  • the reflected light measurement beat signal and the reference beat signal are detected by the light receiver 107 and the light receiver 109 of each of the OCT / FMCW light generation / detection unit 171a and the OCT / FMCW light generation / detection unit 171b.
  • the distance measurement control mechanism control unit 111 processes two sets of signals in parallel. Thereby, the distance measurement of the 1st direction 300a and the 2nd direction 300b can be performed in parallel.
  • the measurement light is output from the optical path switching element 163 in two different directions depending on the combination of the property of the measurement light and the optical path switching element 163. As a result, it is possible to reduce the size of the configuration used for measurement without requiring a configuration such as moving the mirror at the measurement probe tip 164.
  • FIG. 14 is a schematic diagram illustrating an example of the distance measuring device 40 according to the third embodiment.
  • the distance measuring device 30 according to the present embodiment includes a polarization stabilizing device 301 and a linear polarization switching switch 302 at the subsequent stage of the distance measurement control mechanism 110.
  • a 1 ⁇ 2 wavelength plate is used as the polarization state control unit 165.
  • the polarization stabilization device 301 has a function of stabilizing and outputting the polarization state of the input measurement light to linearly polarized light that vibrates in a certain direction.
  • the linearly polarized light changeover switch 302 has a function of rotating the direction of the linearly polarized light of the input measurement light by ⁇ / 2 and outputting it by applying a voltage to the built-in liquid crystal element.
  • the polarization stabilizing device 301 and the linear polarization switching switch 302 are used to output linearly polarized light having a desired vibration direction, and can be realized by a combination of a general polarization state analyzer and a polarization state generator.
  • the angle of the direction in which the optical path switching element 163 rotated by the rotating mechanism 162 reflects light is ⁇
  • the direction of the principal axis of the half-wave plate is ⁇ .
  • FIG. 15 is a diagram for explaining the relative angle relationship of each optical element in the third embodiment.
  • the relationship between the vibration direction angle of the measurement light, the angle of the principal axis of the half-wave plate, and the relative angle of the optical path switching element 163 will be described.
  • the half-wave plate 305 is used as the polarization state control unit 165
  • the polarization beam splitter 180 is used as the optical path switching element 163.
  • the polarization beam splitter 180 transmits linearly polarized light having a vibration direction parallel to the incident surface 309 (that is, emits in the direction of the first direction 300a) and has a vibration direction that forms an angle of ⁇ / 2 with respect to the incident surface 309.
  • the linearly polarized light is reflected (ie, emitted in the direction of the second direction 300b).
  • the half-wave plate 305 tilts and emits the vibration direction of the linearly polarized light by twice the angle that the vibration direction of the incident linearly polarized light forms with the main axis of the half-wave plate 305.
  • the measurement direction of the measurement light incident on the half-wave plate 305 is first turned off by first turning off the linear polarization switching switch 302. Is switched to the first measurement light vibration direction 306a.
  • the half wavelength plate 305 maintains the angle of the main axis 308 of the half wavelength plate 305 at an angle of ⁇ / 2 with respect to the first measurement light vibration direction 306 a incident on the half wavelength plate 305.
  • the measurement light vibration direction 307 emitted from the half-wave plate 305 is kept parallel to the incident surface 309.
  • the measurement light incident on the half-wave plate 305 is first turned on by turning on the linear polarization switching switch 302.
  • the vibration direction is switched from the first measurement light vibration direction 306a to the second measurement light vibration direction 306b.
  • the angle of the main axis 308 of the half-wave plate 305 is the same as that in FIG. 13A (that is, the angle of the main axis 308 of the half-wave plate 305 with respect to the second measurement light vibration direction 306b is ⁇ ).
  • the measurement light vibration direction 307 emitted from the half-wave plate 305 is maintained at an angle of ⁇ / 2 with respect to the incident surface 309.
  • the control of the polarization state control unit driving device 166 can be simplified.
  • the measurement direction can be switched at high speed by changing the measurement direction by electrical control of the linear polarization switch 302 without mechanical operation of the polarization state control unit driving device 166. This realizes a significant reduction in measurement time.
  • the polarization state control unit driving device 166 it is possible to change the measurement direction from the first direction 300a to the second direction 300b by using a general servo motor as the polarization state control unit driving device 166.
  • a general servo motor As the polarization state control unit driving device 166.
  • a servo motor with a rotation speed of 500 rpm it takes a measuring direction switching time of at least about 100 milliseconds because the servo motor is rotated by ⁇ / 4.
  • the configuration shown in the third embodiment enables high-speed measurement direction switching. .
  • FIG. 16 is a diagram illustrating an example of functional blocks of the three-dimensional shape measurement apparatus 50 according to the third embodiment.
  • the three-dimensional shape measuring apparatus 50 includes a polarization switching unit 310 in addition to the function of the three-dimensional shape measuring apparatus 20 shown in FIG.
  • the polarization switching unit 310 is a device that maintains the polarization state of the measurement light in linear polarization and switches the polarization state depending on the measurement direction, and transmits the switched linear polarization to the measurement probe 160.
  • the polarization switching unit 310 corresponds to the polarization stabilization device 301 and the linear polarization switching switch 302.
  • the polarization switching unit 310 (linear polarization switching switch 302) may switch the measurement direction by a user's manual operation, or may switch the measurement direction by control from the distance calculation unit 261.
  • FIG. 17 is a diagram illustrating an example of the configuration of the measurement probe tip 164 according to the fourth embodiment.
  • the measurement probe tip 164 includes one or two condenser lens systems 304 in addition to the optical path switching element 163.
  • the measuring light 303 shaped in the condensing state by the lens system 161 is condensed by the condensing lens system 304 positioned in front of or behind the optical path switching element 163.
  • the condensing position of the measuring light 303 is determined by the condensing lens system 304.
  • a condensing lens system 304 is disposed between the polarization state control unit 165 and the optical path switching element 163.
  • the measurement light in either the first direction 300a or the second direction 300b is collected at the same focal length.
  • FIG. 17B which will be described later, since one condensing lens system 304 is used, manufacturing is simple and the diameter of the measurement probe tip 164 can be reduced.
  • the condensing lens system 304 is disposed between the optical path switching element 163 and the measurement target T in different measurement directions (first direction 300a and second direction 300b).
  • each condensing lens system 304 may be configured such that the measurement light in either the first direction 300a or the second direction 300b is condensed at the same focal length, or different focal points.
  • Each condensing lens system 304 may be configured so as to be condensed at a distance. For example, when the distances a and b for each measurement direction to the target T are greatly different, it is possible to select a focal length corresponding to each distance.
  • a plurality of measurement probe tip portions 164 having different focal lengths may be prepared, and the measurement probe tip portions 164 may be configured to be attachable / detachable with respect to the measurement probe 160. For example, by exchanging the measurement probe tip 164 in accordance with the hole diameter of the target T, it is possible to adjust the condensing position of the measurement light 303 so as to adapt to the distance to the measurement target T.
  • the lens system 161 is provided with a focus variable mechanism such as an electric focus variable lens so that the measurement light can be measured according to the measurement distance to the target T.
  • the focal position can be adjusted.
  • the fourth embodiment by making the measurement probe tip 164 detachable and replaceable, there is no need to provide the lens system 161 with a variable focus mechanism.
  • a plurality of measurement probe tip portions 164 having different lengths in the Z-axis direction may be prepared, and the measurement probe tip portions 164 may be configured to be attachable to and detachable from the measurement probe 160. For example, by exchanging the measurement probe tip 164 according to the depth of the hole of the object T, it is possible to adjust the measurement light so as to surely reach the measurement object T.
  • a plurality of measurement probe tip portions 164 having the same specifications may be prepared, and the measurement probe tip portion 164 may be configured to be attachable / detachable with respect to the measurement probe 160. In this way, when the measurement probe tip 164 is damaged, the entire measurement probe 160 is not repaired but only the measurement probe tip 164 can be replaced.
  • the joint between the measurement probe tip 164 and the measurement probe 160 has a structure capable of restricting the relative positional relationship between the optical path switching element 163 and the polarization state control unit 165, so that adjustment at the time of replacement is simplified.
  • the measurement probe tip 164 in order to maintain distance measurement accuracy, the measurement probe tip 164 needs to suppress expansion / contraction due to environmental temperature change, deflection due to its own weight, or vibration associated with rotation.
  • CFRP Carbon Fiber Reinforced Plastics
  • CFRP Carbon Fiber Reinforced Plastics
  • the configuration of the distance measuring device can be classified into more components according to the processing content. Moreover, it can also classify

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Abstract

L'objectif de la présente invention est de proposer une caractéristique grâce auquel il est possible de réduire la taille d'une partie de mesure dans un dispositif de mesure de distance. Ce dispositif de mesure de distance est caractérisé en ce que : une unité luminescente est prévue qui produit en sortie de la lumière de mesure, une unité de commande d'état de polarisation qui commande la polarisation de la lumière de mesure produite en sortie à partir de l'unité d'émission de lumière, et un élément de commutation de trajet optique qui fait rayonner sélectivement la lumière de mesure commandée par l'unité de commande d'état de polarisation ; l'unité de commande d'état de polarisation commande la polarisation pour que le rayonnement de la lumière de mesure soit effectué vers une pluralité de directions à partir de l'élément de commutation de trajet optique ; et l'élément de commutation de trajet optique absorbe la lumière réfléchie par un objet en raison de la lumière de mesure dont le rayonnement est effectuée à partir de l'élément de commutation de trajet optique, la lumière réfléchie étant utilisée pour mesurer la distance jusqu'à l'objet.
PCT/JP2018/019625 2017-06-06 2018-05-22 Dispositif de mesure de distance et dispositif de mesure de forme tridimensionnelle WO2018225496A1 (fr)

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CA3053315A CA3053315C (fr) 2017-06-06 2018-05-22 Appareil de mesure de la distance et appareil de mesure d'une forme tridimensionnelle
US16/484,844 US10900773B2 (en) 2017-06-06 2018-05-22 Distance measuring device and three-dimensional shape measuring apparatus

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JP2018046769A JP6513846B2 (ja) 2017-06-06 2018-03-14 距離測定装置、及び立体形状測定装置。
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JP2006292642A (ja) * 2005-04-14 2006-10-26 Ricoh Co Ltd 光測長器、光ディスク原盤露光装置、及び加工装置
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JP2014238299A (ja) * 2013-06-06 2014-12-18 キヤノン株式会社 被検物の計測装置、算出装置、計測方法および物品の製造方法
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WO2016024332A1 (fr) * 2014-08-12 2016-02-18 三菱電機株式会社 Dispositif d'envoi et de reception de lumiere laser et dispositif de radar laser
JP2016133393A (ja) * 2015-01-19 2016-07-25 株式会社ニューフレアテクノロジー 欠陥検査装置

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS508668B1 (fr) * 1970-06-19 1975-04-05
US5949546A (en) * 1997-05-14 1999-09-07 Ahead Optoelectronics, Inc. Interference apparatus for measuring absolute and differential motions of same or different testing surface
JP2002031514A (ja) * 2000-07-14 2002-01-31 Hitachi Eng Co Ltd 形状計測装置及び形状計測方法
JP2006292642A (ja) * 2005-04-14 2006-10-26 Ricoh Co Ltd 光測長器、光ディスク原盤露光装置、及び加工装置
JP2007271601A (ja) * 2006-03-07 2007-10-18 Soatec Inc 光学式測定器及び光学式測定方法
JP2015517094A (ja) * 2012-03-23 2015-06-18 ウインダー フォトニクス エー／エスＷｉｎｄａｒ Ｐｈｏｔｏｎｉｃｓ Ａ／Ｓ 複数方向のｌｉｄａｒシステム
JP2014238299A (ja) * 2013-06-06 2014-12-18 キヤノン株式会社 被検物の計測装置、算出装置、計測方法および物品の製造方法
WO2016024332A1 (fr) * 2014-08-12 2016-02-18 三菱電機株式会社 Dispositif d'envoi et de reception de lumiere laser et dispositif de radar laser
JP2016133393A (ja) * 2015-01-19 2016-07-25 株式会社ニューフレアテクノロジー 欠陥検査装置

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