JPWO2014203654A1 - Distance measuring device, shape measuring device, processing system, distance measuring method, shape measuring method and processing method - Google Patents

Abstract

Measurement accuracy in a distance measuring apparatus (method) using a laser is improved. A first step of irradiating a multi-wavelength laser beam, a second step of splitting the multi-wavelength laser beam, and measuring light obtained by irradiating the object with the divided first beam for each wavelength. A third step of converting and detecting as a measurement signal, a fourth step of photoelectrically converting a second beam different from the divided first beam for each wavelength and detecting it as a reference signal, and the measurement signal A distance measuring method comprising: a fifth step of detecting a relative phase with respect to the reference signal and obtaining a distance of the measurement optical path based on the detected relative phase.

Description

  The present invention relates to a distance measuring device, a shape measuring device, a processing system, a distance measuring method, a shape measuring method, and a processing method.

  As background art of this technical field, there is Patent Document 1 (Japanese Patent Laid-Open No. 2003-315027). This publication describes "H-section steel 70 as a method for solving the problem that hot H-section steel has large bends and warpage, so that it has been difficult to control dimensions and shapes with a conventional proximity distance sensor." It is measured by four optical distance meters 40, 41, 42, and 43. For that purpose, the frame 25 is used as a round frame to improve the installation of the optical distance meters 40, 41, 42, and 43 " Is disclosed (summary).

JP 2003-315027 A

  In Patent Document 1, it is necessary to install a measuring device away from an object for measuring the shape of a high-temperature object, and thus it is described that an optical distance meter that can measure the shape remotely is used. Errors due to temperature dependence of light propagation speed due to the principle of measuring the light propagation time between the distance measuring device of the meter and the object are not taken into consideration. That is, the air in the measurement optical path is heated by a high-temperature object, the temperature rises, and the refractive index of the air changes due to changes in humidity and pressure, so the round-trip time from the measurement light measurement device to the object Change, and the distance measured by the light wave rangefinder has no error in the prior art.

  As a means often used in such a case, there is a method of irradiating an object with γ rays and estimating the thickness of the object from the absorption rate of γ rays. Although this method can measure in a high temperature environment, radiation protection measures are necessary to use radiation, and there is a problem that it is not suitable for measuring complex shapes.

  In order to solve the above problems, the present application is directed to a modulation optical system that irradiates multi-wavelength laser light, a beam splitter that divides the multi-wavelength laser light, and a first beam that is split by the beam splitter. A first light receiver that photoelectrically converts measurement light obtained by irradiating an object for each wavelength and detects it as a measurement signal; and a second beam different from the first beam divided by the beam splitter for each wavelength Detecting the relative phase of the second light receiving device that is photoelectrically converted and detected as a reference signal, the measurement signal detected by the first light receiving device and the reference signal detected by the second light receiving device, And a calculation unit for obtaining a distance of the measurement optical path based on the detected relative phase.

  According to the present invention, it is possible to suppress the influence of air temperature, atmospheric pressure, humidity and the like, and to realize highly accurate measurement.

It is an example of the block diagram of the distance measuring device which concerns on this invention. It is a related figure of temperature and distance in a distance measuring device concerning the present invention. It is a block diagram of the circuit for converting the frequency of the received light signal by this invention. It is a block diagram at the time of using an optical comb laser for the distance measuring device which concerns on this invention. It is a block diagram of the distance measurement part at the time of using a frequency sweep laser in the shape measuring apparatus which concerns on this invention. It is a block diagram of the distance measuring apparatus (shape measuring apparatus) which concerns on this invention. It is a block diagram for calibrating distance correction by the distance measuring device by this invention. It is a block diagram of the apparatus which combined the object surface temperature measurement function by this invention, and raised the precision of distance measurement further. It is a block diagram of the processing system which concerns on this invention. It is a figure which shows the mode of the sweep of the laser for performing distance correction by the shape measuring apparatus which concerns on this invention. It is a figure which shows the structural example which measures D2-D1 of this invention with high precision. It is a figure which shows the example of a light chopper. It is a figure which shows the structural example which has arrange | positioned the laser absorption part and the laser reflection part in the vicinity of the beam scanning mirror of a shape measuring apparatus. It is a figure explaining the sequence of measurement. It is a figure which shows the modification of the distance measuring device which acquires crosstalk data and reference distance data with high frequency. FIG. 10 is a diagram showing a modification of Example 10. It is a figure which shows the structural example of a distance measuring device. It is a figure which shows the structural example of a distance measuring device. It is a figure which shows the structural example of the modulation optical system of the distance measuring device which concerns on this invention. It is a figure which shows the structural example of the modulation optical system of the distance measuring device which concerns on this invention. It is a figure which shows the structural example of the modulation optical system of the distance measuring device which concerns on this invention. It is a figure which shows the structural example of the modulation optical system of the distance measuring device which concerns on this invention. It is a figure which shows the structural example of the modulation optical system of the distance measuring device which concerns on this invention. It is a figure which shows the structural example of the distance measuring device at the time of making a light receiver into common with (lambda) 1 and (lambda) 2. It is a figure which shows the processing system which concerns on this invention.

  Hereinafter, examples will be described with reference to the drawings.

In order to solve the above-mentioned problem, in the present application, by using a plurality of wavelengths of measurement light, the distance to the object is measured at the same time, and the difference between the two is used to correct the measurement distance. It is characterized by realizing distance measurement and solid shape measurement. The optical distance meter modulates the intensity of the measurement light at a fixed frequency, and the phase of the intensity modulation that is detected changes depending on the time when the intensity-modulated light scattered and reflected by the object returns. You can see the distance. That is, the relationship between the refractive index n of the atmosphere, the light velocity c in the vacuum, the frequency f of the intensity modulation, the phase φ of the intensity modulation of the received light and the distance D indicates that the propagation distance of light for one intensity modulated wave is c / Since (n · f),
D = (1/2) · (N + φ / (2π)) · c / (n · f)
There is a relationship. Here, N is an integer. In order to determine N, a plurality of modulation frequencies f are used. First, a small modulation frequency f such that the distance c / (2n · f) per cycle is larger than the distance range to be measured is used. The distance L is accurately obtained by determining a rough distance and gradually increasing the modulation frequency f.

  Here, the refractive index of the atmosphere changes depending on the environment such as the temperature, pressure, and humidity of the atmosphere. At this time, the value of (N + φ / (2π)) changes in proportion to the refractive index n. For this reason, the apparent distance D calculated on the assumption that the refractive index n is constant varies in proportion to the refractive index. Since the degree of change in refractive index varies depending on the wavelength of light, the distance measurement value varies depending on the wavelength. Due to this difference, an error caused by the environment can be estimated. This is shown in FIG.

  FIG. 2 is a relationship diagram of temperature and distance in the distance measuring apparatus according to the present invention.

Since the refractive index generally decreases as the temperature increases, the apparent measurement distance changes in proportion to this. Due to the wavelength dependence of the change in refractive index due to the environment, the measurement distance D1 at the wavelength λ1 and the measurement distance D2 at the wavelength λ2 (<λ1) change differently with respect to the temperature. At this time, the relationship between the values of D2 and D1 and the true distance D is
D = D2-A (D2-D1)
Thus, the measurement distance in the high-temperature atmosphere can be corrected. Here, the difference between D1 and D2 is negligible, and A has a large value of about 100. Therefore, it is necessary to detect a slight difference between D1 and D2 with high accuracy. For this reason, the influence of the common error is reduced by symmetrically configuring the measurement light and the reference light, and the detection circuit systems of wavelength 1 and wavelength 2.
FIG. 1 is a configuration diagram of a distance measuring apparatus according to the present invention.

  A signal from the oscillator 100 is applied to the modulation light source 101 to generate laser light modulated at the modulation frequency of the oscillator. A laser diode may be used as the light source, and a signal from the oscillator 100 may be superimposed on the driving current of the laser diode. Alternatively, a signal from the oscillator 100 may be input as a modulator drive signal using a continuous wave laser light source and a light source 101 to which a modulator is connected thereafter. As the modulator, an electro-optic modulator EOM (Electro-Optical Modulator), an acousto-optic modulator AOM (Acoustic-Optical Modulator), or the like may be used. In particular, EOM can perform high-speed modulation of several tens of GHz. If it is desired to increase the distance measurement accuracy by increasing the frequency f, it is desirable to use EOM.

  The laser light is collimated by the collimator 102 and then guided to the wavelength converter 103, where harmonics are generated using the nonlinear optical effect. Assuming that the original wavelength is λ1, the laser beam having a wavelength λ2 that is a fraction of this integer is a harmonic. In addition to the harmonics, sum frequency or difference frequency laser light generated by mixing in a nonlinear medium with light of other wavelengths may be generated. Since the light of wavelength λ1 is modulated, the generated light of wavelength λ2 is also modulated in synchronization with the original light accurately, and a mixture of these lights is emitted from the wavelength converter 103. The emitted light passes through the beam splitter 104, passes through the optical filter 105, exits from the projection / detection lens 106, and is irradiated on the measurement object 12 as the measurement light 20. The light scattered and reflected at 12 passes through the projection / detection lens 106 and the optical filter 105 again, and is reflected downward by the beam splitter 104 in the figure. Here, as a desirable configuration, the light emitted from the wavelength converter 103 is configured to be in a linear polarization state, the beam splitter 104 is a polarization beam splitter, and the polarization state of the light emitted from the wavelength converter 103 It is possible to adjust the intensity cost of the light that passes through the beam splitter 104 and becomes the measurement light and the light that is reflected upward and becomes the reference light. Furthermore, by using a ¼ wavelength plate as the optical filter 105 and adjusting the light transmitted through the optical filter 105 toward the measurement object 12 to be circularly polarized, much light is scattered and reflected from the measurement object 12. Becomes a circularly polarized light component, and is transmitted again through the quarter-wave plate placed on the optical filter 105, so that it returns to the polarization beam splitter 104 as linearly polarized light whose polarization direction is rotated 90 degrees from the first. Then, the light is reflected downward by the polarization beam splitter 104. Further, the optical filter 105 may include a wavelength filter for cutting disturbance light components other than the measurement light λ1 and λ2 in addition to the quarter wavelength plate.

  The downward direction of the beam splitter 104 is the light receiving portion for the measurement light, and the upward direction is the light receiving portion for the reference light, which is configured symmetrically. First, the configuration and operation of the light receiving portion for the measurement light will be described. The measurement light is divided into light of wavelength λ1 and light of wavelength λ2 by the wavelength separation mirror 110M. The light of wavelength λ1 travels in the left direction in the figure and is received by the light receiver 111M1, converted into an electrical signal, and a signal corresponding to the modulation frequency of the oscillator 100 is extracted from this electrical signal by the filter 112M1. The light of wavelength λ2 travels downward in the figure and is received by the light receiver 111M2, converted into an electrical signal, and a signal corresponding to the modulation frequency of the oscillator 100 is extracted from this electrical signal by the filter 112M2.

  Next, the upward direction of the beam splitter 104 will explain the configuration and operation of the light receiving portion of the reference light. The reference light is divided by the beam splitter 104, and then divided by the wavelength separation mirror 110R into light of wavelength λ1 and light of wavelength λ2. The light of wavelength λ1 travels in the left direction in the figure and is received by the light receiver 111R1, converted into an electric signal, and a signal corresponding to the modulation frequency of the oscillator 100 is extracted from the electric signal by the filter 112R1. The light of wavelength λ2 travels upward in the figure and is received by the light receiver 111R2, converted into an electrical signal, and a signal corresponding to the modulation frequency of the oscillator 100 is extracted from this electrical signal by the filter 112R2.

  From these four types of extracted signals, the phase difference between the measurement light of wavelength λ1 and the reference light is measured by the phase meter 113-1, and the phase difference between the measurement light of wavelength λ2 and the reference light is calculated by the phase meter 113-2. Respectively, and from these, the distance D1 with respect to the wavelength λ1 and the distance D2 with respect to the wavelength λ2 are detected. The distance calculation circuit 114 receives these pieces of information, and an accurate distance D in which the influence of the refractive index is corrected can be obtained by D = D2-A (D2-D1).

  As already described, in the case of long distance measurement, since the integer N is uniquely determined, it is necessary to perform the above detection using a plurality of modulation frequencies. In other words, the modulation frequency f of the light source 101 is switched, and the filter 112 sequentially switches the extraction of this modulation frequency component, thereby eliminating the indefiniteness associated with the phase detection periodicity. The filter 112 may be configured so as to pass all the modulation frequencies to be switched. If the equivalent band is switched in accordance with the switching of the frequency f, the filter 112 becomes stronger against disturbance. Alternatively, modulation applied from the oscillator 100 to the light source 101 is applied to each of the frequencies obtained by superimposing a set of the filters 112M1, 112M2, 112R1, 112R2, and the phase meters 113-1 and 113-3 as a signal obtained by superimposing the plurality of frequencies to be switched. On the other hand, by providing in parallel, a configuration is possible in which the distance can be measured at a higher speed without switching the frequency.

  In addition, slight fluctuations occur in the phase of the filtered signal due to the influence of drift in the filter characteristics of the filter 112 and the like. In order to suppress this influence, a symmetric optical path is configured with respect to λ1 and λ2, but a configuration in which the movable reflecting mirror 128 is inserted into the measurement optical path is also conceivable. When the movable reflecting mirror 128 is inserted in the optical path, the distance to the mirror 128 very close to the beam splitter 104 can be measured, and this value is not easily influenced by atmospheric disturbances. Can be suppressed by periodically calibrating.

  With the configuration described above, it is possible to realize a distance meter in which the influence of the temperature, atmospheric pressure, and humidity of the optical path of the measurement light 20 is reduced by accurately measuring and correcting the distances at a plurality of wavelengths.

  Next, another embodiment of the phase detection method will be described with reference to FIG.

  FIG. 3 is an example of a configuration diagram of a circuit for converting the frequency of the received light signal according to the present invention.

  In order to measure the distance with high accuracy, it is desirable to detect the phase of light modulated at a high frequency f. However, since it is difficult to handle a high-frequency signal, an embodiment using a method called beat down will be described in this embodiment. The portion of the filter 112 of the distance measuring device in FIG. 1 is as shown in FIG. That is, the mixer 118 is inserted after the frequency extraction filter 112 corresponding to the modulation frequency f1, and is mixed with another frequency f2 generated by the oscillator 100, that is, analog multiplication is performed. Then, a signal including two frequencies f1 + f2 and f1-f2 is output. Of these, a signal that is beat-down to f1-f2 by passing through a frequency extraction filter 119 corresponding to the frequency of f1-f2 Become. If close values are selected as f1 and f2, the frequency can be lowered by orders of magnitude by this beat down, so that the phase meter 113 can be easily configured.

  Furthermore, as another beat-down embodiment, as shown in FIG. 3B, a signal having the second frequency f2 generated from the oscillator is applied to the light receiver 111. If an avalanche photodiode is used as the light receiver 111 and a signal having a frequency f2 is applied to the bias voltage, the multiplication gain changes depending on the applied voltage, so that it functions equivalent to a multiplier. Therefore, it is possible to beat down to the frequency f1-f2 by inserting the filter 119 that transmits the difference frequency f1-f2 after this.

  Next, another embodiment of the distance detector (distance measuring device) 10 will be described.

  FIG. 4 is a configuration diagram when an optical comb laser is used in the distance measuring device.

  In the present embodiment, a laser 101 'called a mode-locked laser or an optical comb laser is used in order to perform accurate phase detection by accurately modulating at a high frequency. The mode-locked laser is a pulsed laser with a repetition frequency f1, and the resonance modes from the low order to the high order are accurately synchronized in the laser resonator, so that the frequency f1 is 1 time, 2 times, 3 times. The modulation is applied in synchronization with high order and the jitter is very small. Because of such characteristics, the accuracy of distance measurement is improved when this optical comb laser 101 'is used in place of the light source 101 shown in FIG. In this case, the modulation signal f1 from the oscillator 100 is not used for modulation of the optical comb laser 101 ′, but for controlling the resonator length of the optical comb laser so that the repetition oscillation frequency of the optical comb laser 101 ′ is equal to f1. Used as a reference signal. The parts other than the light source may of course be configured in the same manner as in FIG. 1, but in order to detect a high frequency on the order of several tens of GHz, which is difficult to obtain by modulation of the laser diode, as shown in FIG. It may be configured. A light receiver that detects light intensity modulation on the order of several tens of GHz is very expensive, and high-frequency waves easily propagate through space and circuit boards to the circuit after the light receiver, resulting in crosstalk noise. When the modulated light signal received at is weak, it tends to cause an error. For this reason, it is possible to detect the phase of the weak light with high accuracy while suppressing the crosstalk by optically converting to another frequency and then detecting with the light receiver.

  In the following, a description will be added with a focus on the difference between FIG. 4 and FIG. The downward direction of the beam splitter 104 is the light receiving portion for the measurement light, and the upward direction is the light receiving portion for the reference light, which is configured symmetrically. First, the configuration and operation of the light receiving portion for the measurement light will be described. Measurement light is introduced into an optical fiber by a fiber collimator 115M, and is divided into light having a wavelength λ1 and light having a wavelength λ2 by a wavelength separation coupler (WDM) 116M. When the light of wavelength λ1 passes through an optical modulator 117M1, such as an EOM, after being modulated at the frequency f2 from the oscillator 100, it is received by the light receiver 111M1 and converted into an electrical signal. Due to the intensity modulation at the frequency f1 of the original measurement light and the intensity modulation f2 by the optical modulator 117M1, the received signal includes a signal component that is beat-down of f1-f2. Since the modulation component at the original frequency f1 is a high frequency, even if the modulation component deviates from the band of the light receiver 111M1, it is only necessary to detect f1-f2 converted to a low frequency, so it is possible to use a lower cost light receiver. There is an effect other than the crosstalk suppressing effect. From this electrical signal, a signal corresponding to the frequency f1-f2 is extracted by the filter 112M1.

  Further, the frequency of the modulation signal applied to the optical modulator 117M1 may be f2 / 2 instead of f2. When the modulation intensity is increased, modulation with harmonics is applied, so that a beat-down signal of f1-f2 can be obtained similarly. In this case, since the signal frequency of the oscillator can be lowered, the maximum frequency of the circuit can be lowered.

  The light of wavelength λ2 is guided from the wavelength separation coupler 116M to the optical modulator 117M2, and similarly subjected to intensity modulation by the frequency f2, and converted into an optical signal including a signal of the frequency f1-f2. This is received by the light receiver 111M2 and converted into an electrical signal, and a signal component of frequency f1-f2 is extracted from this electrical signal by the filter 112M2.

  Next, the configuration and operation of the light receiving portion of the reference light reflected upward from the beam splitter 104 will be described. The reference light is divided by the beam splitter 104 and then guided to the optical fiber by the fiber collimator 115R. The subsequent configuration is symmetric with respect to the figure for the detection light, and all symbols M for the optical modulator, light receiver, and filter in the above description may be replaced with R.

  The phase difference between the measurement light having the wavelength λ1 and the reference light from the four types of signals extracted above is obtained by the phase meter 113-1, and the phase difference between the measurement light having the wavelength λ2 and the reference light is obtained by the phase meter 113-2. , And detect the distance D1 with respect to the wavelength λ1 and the distance D2 with respect to the wavelength λ2, respectively. The distance calculation circuit 114 receives these pieces of information, and an accurate distance D in which the influence of the refractive index is corrected can be obtained by D = D2-A (D2-D1).

  In this configuration, since the measurement light is introduced into the core of a small area of the optical fiber by the fiber collimator 115M, it is desirable that the lens 106 has a focus adjustment mechanism. In addition, it is desirable that ambient light other than the wavelengths λ1 and λ2 be cut by the optical filter 105. In addition, it is desirable to correct errors due to drift of the filter circuit or the like by periodically measuring the distance of the movable mirror with the movable mirror 128.

  Next, as another embodiment, a configuration in the case where the intensity of light is not modulated but the frequency of light is modulated will be described.

  FIG. 5 is a configuration diagram when a frequency sweep laser is used in the distance measuring apparatus according to the present invention.

  The oscillator 100 ′ generates a triangular modulation signal and is superimposed on the drive current of the laser diode 101. Then, it can control so that the frequency as an electromagnetic wave of the laser beam of wavelength λ1 oscillated by the LD changes linearly. This laser beam is divided by a fiber coupler 129, and one is further divided into two by another fiber coupler 133-1. One light beam directed to the side is further divided by another fiber coupler 134-1, mixed with a laser having another wavelength λ 2 by a wavelength separation (WDM) coupler, and emitted from the collimator 102.

  The emitted light passes through the optical filter 105, is then emitted from the projection / detection lens 106, and is irradiated on the measurement object 12 as measurement light 20. The light scattered and reflected at 12 passes through the projection / detection lens 106 and the optical filter 105 again, and is collected by the fiber collimator 102. It is desirable that the lens 106 has a focus adjustment mechanism as in the third embodiment.

The collected light of wavelength λ1 is guided downward by the wavelength separation coupler 110, is branched to the mirror 135-1 by the fiber coupler 134-1, and is recombined with the light that has returned to the mirror and returned to the mirror 135-1. Are detected by the photodetector 111M1. At this time, a beat signal in which the light returned from the mirror 135-1 interferes with the light returned from the measurement object 12 is detected. Assuming that the rate of change of the frequency of the laser light due to the modulation of the laser diode 101 is k (Hz / s), the light D has a difference D between the optical distance to the mirror 135-1 and the optical distance to the measurement object 12. Since the propagation time differs by 2D / c, the beat when two lights interfere is fb = 2k · D / c
With a frequency of Therefore, if this frequency is detected, the distance D can be calculated.

The laser beam branched downward by the fiber coupler 133-1 is divided into two by another fiber coupler 136-1, led to optical fibers 137-1 and 138-1 having different lengths by L, and the two The light propagated through the optical fiber is combined by another fiber coupler 139-1 to cause interference, and is detected by the photodetector 111R1. The beat frequency at this time is fr = k · nf · L / c
It becomes. Here, nf is the refractive index of the core of the optical fiber. Since the frequency change rate other than k is known, the frequency change rate can be monitored from the beat frequency fr, and this is detected by the AD converter 141-1 as a reference. At the same time, the beat signal of the detection light detected by the detector 111M1 is also detected by the AD converter 141-1. If these two types of beat signals are analyzed to analyze the frequency ratio, the distance D can be calculated. In this case, since the frequency multiplier 140-1 is not used, the frequency multiplier 140-1 will be described later. The final formula for calculating D is D = (1/2) nf · L · fb / fr
Thus, the distance D can be calculated from the ratio between the detected light beat and the reference beat.

  Alternatively, as another method, the reference beat signal obtained from the photodetector 111R1 is not directly input to the AD converter 141-1, but is multiplied by about 4 to 16 times through the frequency multiplier 140-1, and this is converted to AD. If the beat signal of the detection light detected by the detector 111M1 is AD-converted as the sampling trigger signal of the converter 141-1, the detected beat is frequency-analyzed using Fourier transform or the like without comparing the detected beat and the reference beat. The distance D can be measured only by this.

  Next, the upper half of FIG. 5, which is an optical system / circuit system corresponding to another wavelength λ2, will be described. The remainder of the laser light divided by the fiber coupler 129 is amplified by an optical amplifier 130 such as a rare earth-doped optical fiber or a semiconductor optical amplifier and emitted from a fiber collimator 131. The amplified light is guided to the wavelength converter 103, where harmonics are generated using a nonlinear optical effect. Assuming that the original wavelength is λ1, the laser beam having a wavelength λ2 that is a fraction of this integer is a harmonic. In addition to the harmonics, sum frequency or difference frequency laser light generated by mixing in a nonlinear medium with light of other wavelengths may be generated. Since the input light having the wavelength λ1 is modulated, the generated light having the wavelength λ2 is also modulated in synchronism with the original light accurately and guided again to the optical fiber by the fiber coupler 132. The light of wavelength λ2 is input to a distance detection system using an optical fiber optical system having the same configuration as described for the light of wavelength λ1 in the description of the lower half of FIG. If all the subscripts of the optical elements 134-1, 135-1, 111M1, 136-1, 137-1, 138-1, 139-1, 111R1 and circuits 140-1, 141-1 are read from 1 to 2, , Λ1 holds true for λ2.

  However, it should be noted that since the rate of change k of the frequency of light has been multiplied by λ1 / λ2 by using harmonics, the beat frequency is also increased by λ1 / λ2. Here, as another configuration, regarding the optical system that generates the reference beat, since the beat frequency is accurately multiplied by λ1 / λ2, it is not always necessary to separately provide λ1 and λ2. For example, instead of having the reference beat generating unit for λ1 142-1 surrounded by the dotted line in the figure, the signal from the reference beat generating unit for λ2 142-2 is input to the AD converter 141-1 for the wavelength λ1 through the path 145 May be.

  With the above configuration, the distances D1 and D2 of the object 12 with respect to the wavelengths λ1 and λ2 can be accurately measured. By inputting these results to the distance calculation circuit 114 ′ and comparing them, an error due to the environment of the optical path can be obtained. It becomes possible to measure the corrected accurate distance D.

  In this configuration, since the measurement light is introduced into the core of a small area of the optical fiber by the fiber collimator 102, the lens 106 is preferably provided with a focus adjustment mechanism. In addition, it is desirable that ambient light other than the wavelengths λ1 and λ2 be cut by the optical filter 105. In addition, it is desirable to correct errors due to drift of the filter circuit or the like by periodically measuring the distance of the movable mirror with the movable mirror 128.

  Next, the configuration of the three-dimensional shape measuring apparatus 11 including the distance measuring apparatus 10 described above will be described.

  FIG. 6 is an example of a configuration diagram of the shape measuring apparatus 11 according to the present invention.

  The measurement light 20 emitted from the distance measuring device 10 is reflected by the movable mirrors 150 and 151 of the shape measuring device 11 and then irradiated to the measurement object 12, and the diffusely reflected measurement light 20 is reflected by the movable mirrors 151 and 150. Return to the distance measuring device 10. By changing the angles of the movable mirrors 150 and 151, a deflection optical system that deflects the beam in an arbitrary direction is configured. By measuring the distance to the object 12 while scanning the direction of the beam with this deflecting optical system, the three-dimensional shape of the object can be measured. As another example, the mirror 151 may be configured to be movable in a biaxial manner by using only one mirror 151 so that the three-dimensional shape can be measured with only one mirror. Alternatively, only one mirror 151 may be used, and the mirror 151 may be configured to be movable only in a single-axis method, and the cross-sectional shape along the scanning direction of the measurement light 20 may be measured.

  In FIG. 6, the distance measuring device 10 is depicted using the configuration described in FIG. 1, but it is needless to say that any one of FIGS. 3, 4, and 5 may be used.

  Next, the calibration method of this apparatus will be described with reference to FIG.

  FIG. 7 is a configuration diagram for calibrating the distance correction by the distance measuring device 10 (shape measuring device 11) according to the present invention.

A heating tube 152 capable of heating and monitoring the temperature is prepared to cover the optical path of the measuring light 20 between the distance measuring device 10 or the shape measuring device 11 and the calibration target 12 ′. While changing the temperature of the heating tube, the distances D1 and D2 by the wavelengths λ1 and λ2 are measured to obtain the data shown in FIG. From this data, the formula D = D2-A (D2-D1)
The coefficient A necessary for correction by the above can be obtained.

  Next, an embodiment for further improving the distance accuracy will be described with reference to FIG.

  FIG. 8 is an example of the configuration of an apparatus that combines the object surface temperature measurement function according to the present invention to further improve the accuracy of distance measurement.

  The relationship shown in FIG. 2 is an approximate relationship, and when the temperature range is widened, the equation D = D2-A (D2-D1) does not exactly match. For this reason, if a function for measuring the temperature of the surface of the measurement object 12 is added, the temperature gradient of the air near the measurement object is estimated using this information, and correction is performed, the shape measurement accuracy at high temperatures improves. To do. FIG. 8 will be described only with respect to the differences from the embodiment described in FIG. The measurement light returned from the measurement object 12 is configured to pass through the lens 106, pass through the components of the detection light λ 1 and λ 2 through the wavelength separation mirror 153, and reflect other light. Components other than the detection lights λ1 and λ2 are received at 154. Reference numeral 154 denotes a spectroscope, which can estimate the surface temperature of the measurement object 12 from the spectrum of the radiation light using the Wien radiation law or the Planck radiation law. Or, more simply, 154 may be constituted by a light receiver with a wavelength filter, and the surface temperature of the measurement object 12 may be estimated from this by detecting the amount of light in a certain infrared wavelength region. In this way, the wavelength estimation mirror can be provided by the wavelength separation mirror 153 and the spectroscope / receiver with wavelength filter 154. The temperature gradient of the air in the vicinity of the measurement object is estimated from the surface temperature of the measurement object 12 thus estimated, and the measured distance is corrected. The correction amount for this can be obtained by the heating tube 152 described in FIG.

  Next, a processing system having a three-dimensional shape evaluation device 13 that evaluates a three-dimensional shape using the measurement result of the shape measuring device 11 according to the present invention, and adjusting the processing conditions of the processing device using the three-dimensional shape evaluation result. This will be described with reference to FIG.

  The machining system shown in FIG. 9 includes shape measuring devices 11-1 and 11-2, a three-dimensional shape evaluation device 13, and a machining device 14.

  Reference numerals 11-1 and 11-2 denote solid shape measuring apparatuses according to the present invention. As described above, if necessary, one or a plurality of three-dimensional shape measuring devices are installed around the measurement object 12, and the measurement light 20-1 and 20-2 are scanned to obtain the three-dimensional shape of the measurement object 12. To do. Measurement data from these three-dimensional shape measuring devices are collected by the three-dimensional shape evaluation device 13 and the deviation between the three-dimensional data and the design value is evaluated with high accuracy as the three-dimensional data of the entire measurement object 12. This result is passed to a processing device 14 such as a forging device or a rolling device, and the operation parameters of the processing device can be changed to control the shape of the measurement target object 12 as a desired shape. .

  FIG. 10 is a diagram showing a state of laser sweep for performing distance correction by the shape measuring apparatus according to the present invention.

  The measurement light 20 emitted from the shape measuring device 11 is scanned to measure the surface shape of the measurement object 12. At this time, in order to accurately obtain correction amount data based on air pressure, temperature, humidity, etc., the measurement is performed slowly and smoothed for a long time, and the distances D1 and D2 by the respective wavelengths λ1 and λ2 are accurately measured. There is a need to. In order to avoid an increase in measurement time due to this, correction data at a small number of positions is acquired as shown at 21 in FIG. 10A, a map of correction amounts according to locations is obtained by interpolation, and the shape measuring apparatus 11 The distance calculation unit 114 corrects the measurement result at each position. With this configuration, it is possible to accurately obtain the three-dimensional shape data without increasing the measurement time and the measurement variation. Further, as shown in FIG. 10B, the distance calculation unit 114 of the shape measuring device 11 is measured by placing an auxiliary target 22 that can detect a stable distance with strong reflected light at a correction data acquisition position, and measuring this. This produces an effect that the value at each position of the correction amount at the time of measuring the high temperature object can be obtained accurately.

  In the above embodiment, the configuration diagram of the shape measuring device is described with reference to FIG. 6 shown in the fifth embodiment. However, the distance measuring device shown in the other embodiments is also provided with a movable mirror or the like as in FIG. By being provided, it is configured as a shape measuring device.

As already explained, D = D2-A (D2-D1) of the distance correction formula
The difference between D1 and D2 is very small. Since A has a large value of about 100, it is necessary to detect a slight difference between D1 and D2 with high accuracy. For example, in order to obtain an accuracy of 100 micrometers, it is necessary to measure the value of D2-D1 with an accuracy of 1 micrometer. For this purpose, an embodiment that can further improve the accuracy will be described later.

  FIG. 11 shows a configuration example for measuring D2-D1 of the present invention with high accuracy. The relative signal phase of D2 and D1 depends on the difference in the drift effect of the filter characteristics due to the heat generation of the circuit such as the filter 112 and the environmental temperature, and the difference in the optical path length in the distance measuring device 10 between the reference light and the detection light. Even if the environment of the optical path of the measurement light 20 and the distance of the measurement object 12 do not change at all, slight fluctuations occur. In order to suppress this influence, in the configuration described with reference to FIG. 1, the movable reflecting mirror 128 can be inserted into the measurement optical path, and the distance to the mirror 128 very close to the beam splitter 104 can be measured. Because of this value, the effect of drift in the filter characteristics was periodically calibrated and suppressed by this value. Further, the configuration of the embodiment described with reference to FIG. 11 increases the accuracy by frequently performing this. An optical chopper 172 is inserted instead of the movable reflecting mirror 128. By constantly rotating the controller 162 and operating the crosstalk corrector 163 and the origin corrector 164 in synchronization therewith, the detection drift described above is corrected at a high frequency by performing the correction at all times. D2-D1 can be obtained with high accuracy.

  As the optical chopper used here, for example, the one shown in FIG. The rotating disk portion of the optical chopper 172 is formed with a laser absorbing portion 170 that absorbs light without reflecting it, and a laser reflecting portion 171 that reflects light and returns it to its original state. The window or transparent glass part.

  Alternatively, as shown in FIG. 12B, a laser absorption unit 170 ′ and a laser reflection unit 171 ′ are disposed in the vicinity of the beam scanning mirror 150 in the configuration diagram of the shape measuring apparatus described with reference to FIG. 6. The laser reflecting unit 171 ′ is a mirror that returns light to the beam scanning mirror 150. When the angle of the scanning mirror 150 is controlled so that the beam hits the laser reflecting unit 171 ′, the laser reflecting unit 171 ′ performs measurement. The light is reflected back to the detector. In addition, when the angle of the beam scanning mirror 150 is controlled so that the beam strikes the laser absorbing portion 170 ′, the light does not return. In this embodiment, the light is absorbed by being reflected a plurality of times by an ND filter that absorbs light. The laser absorption unit 170 ′ and the laser reflection unit 171 ′ may be arranged after the second beam scanning mirror 151 to switch the measurement optical path according to the angle of 151.

  A measurement sequence will be described with reference to FIG. As described above, the normal measurement period in which the measurement light is applied to the measurement object by the rotation of the light chopper 172 or the beam scanning mirror 150 or 151, the reference distance measurement period in which the laser reflection unit 171 is measured, the laser The background measurement period in which the absorption unit 170 absorbs the beam and measures the background signal is switched at high speed at an appropriate interval between 1 millisecond and 10 seconds. The optical chopper 172 and the beam scanning mirror 150 or 151 are controlled by the controller 162, and the operations of the crosstalk corrector 163 and the origin corrector 164 are switched using a timing signal from the optical chopper 172 or the controller 162.

  Specifically, the crosstalk corrector 163 stores the data D ″ (phase φ and amplitude A) from the phase meter as amplitude vectors (Ax, Ay) during the background measurement period, and the background data (Axn, Here, there is a relationship of Ax = Acosφ and Ay = Asinφ. During other periods, data from the phase meter is received as an amplitude vector D ″ (Ax, Ay), and D ′ (Ax−Axn, Ay-Ayn) is output as data after background correction. In order to reduce background data identification errors, background data (Axn, Ayn) may be obtained by using background data of a plurality of background measurement periods and applying various types of filters such as moving averages. .

  The origin corrector (comparator) 164 stores the data of the reference distance measurement period among the data D ′ received from the crosstalk corrector 163 and subtracts it from the data D ′ of the normal measurement period as (Axo, Ayo). An accurate measurement is realized by removing the influence of the characteristic drift of the filter and the optical path in the distance measuring device 10. Again, in order to reduce the measurement error of the reference distance, data obtained by applying various types of moving averages or the like using the data of a plurality of reference distance measurement periods may be used as the reference distance data (Axo, Ayo).

  Since the above processing is performed for each of the wavelengths λ 1 and λ 2, the phase meter 113, the crosstalk corrector 163, the origin corrector 164, and the data D ″, D ′, D output therefrom are 1, 2 respectively. Although not shown in the figure, the above processing is performed for each of a plurality of modulation frequencies f as described in the first embodiment, whereby the distance per cycle is obtained. Using a small modulation frequency f such that c / (2n · f) is larger than the distance range to be measured, thereby determining a rough distance, and gradually increasing the modulation frequency f to obtain the distance accurately. Finally, the distance calculation circuit 114 corrects the temperature change of the refractive index of the atmosphere from the distances D1 and D2 to the two wavelengths λ1 and λ2 by D = D2-A (D2-D1). It can be determined precise distances.

  Next, a modification for obtaining the crosstalk data and the reference distance data with high frequency will be described with reference to FIG. The basic configuration is the same as that of the distance measuring apparatus 10 described in FIG. However, optical fiber couplers 160-1 and 160-2 are inserted after the electro-optic modulators (EOM) 117R1 and 117R2, respectively, and a part of the reference light is branched to another optical fiber. The branched optical fibers are coupled to the optical fibers from the EOM (117M1 and 117M2 respectively) of the measurement light by optical switches 161-1 and 161-2. The optical switch switches between the normal measurement period and the reference distance measurement period described in the ninth embodiment by switching the measurement light and the reference light according to a signal from the controller 162 and passing them to the photoelectric converters (111M1 and 111M2 respectively). Further, assuming that the optical switches 161-1 and 161-2 are switched to the three inputs, the third input is disconnected and the controller 162 selects the unconnected input, thereby allowing the background described in the ninth embodiment. Realize the measurement period. The controller 162 controls the crosstalk corrector 163 and the origin corrector 164 in synchronization with the selection of the measurement period in the same manner as in the ninth embodiment, thereby removing the influence due to the characteristic drift of the filter and the optical path in the distance measuring apparatus 10. To achieve accurate measurements.

  Next, a modification of the tenth embodiment will be described with reference to FIG. Here, the optical fiber coupler 160 is inserted after the fiber collimator 115R for reference light, the reference light is partially branched, and the optical fiber switch inserted after the fiber collimator 115M for measurement light is selected as measurement light, This is sent to the WDM coupler for measurement light (116M). The selection is performed by a signal from the controller 162, and the fiber coupler 160 has two inputs or preferably three inputs and the third input is used without being connected as in the tenth embodiment.

  Another configuration example will be described with reference to FIG. The basic configuration is the same as that of the distance measuring apparatus 10 described in FIG. However, an element to be described later is inserted between the wavelength separation coupler 110 and the collimator 102 to switch the light returning from the wavelength separation coupler 110 to the left in the drawing. The circulator 166 guides the measurement light from the wavelength separation coupler 110 to the optical fiber coupler 160. The optical fiber coupler 160 branches a part of the light to the optical switch 161. The light that has not been branched travels to the right, travels through the circulator 165 to the right, and is guided to the collimator 102. From here, the measurement light 20 is irradiated on the measurement object 12 and returned to the optical fiber by the collimator again, as described with reference to FIG. The returned measuring light 20 is guided upward by the circulator 165 and input to the optical switch 161. Based on the signal from the distance calculation circuit 114 ′, the optical switch 161 selects light returned from the optical coupler 160 before irradiation, light irradiated as the measurement light 20, and more preferably light from a port to which no input is connected. Output. The circulator 166 receives this and transmits it to the wavelength separation coupler 110. With this configuration, the optical switch realizes switching between the normal measurement period, the reference distance measurement period, and the background measurement period described in the ninth embodiment. Similar to the ninth embodiment, the distance calculation circuit 114 ′ performs the background correction and the reference distance data correction in synchronization with the selection of the measurement period, thereby removing the influence of the filter in the distance measuring apparatus 10 and the characteristic drift of the optical path. To achieve accurate measurements.

  Still another configuration example will be described with reference to FIG. The basic configuration is the same as that of the distance measuring apparatus 10 described in FIG. However, the detection signal of the reference light is branched after the photoelectric converters 111R1 and 111R2 and guided to the signal switchers 181-1 and 181-2, respectively. The switch 181-1 switches the signals from the measurement light receiver 111M1 and the reference light receiver 111R1 according to a command from the controller 162 and sends the signals to the filter 111M1. This makes it possible to measure the difference in characteristics between the filters 112M1 and 112R1 during the period when the switch selects the signal from the reference light, and this is performed frequently, and the phase of the signal from the measurement light is measured. By correcting at the time of measurement, phase measurement with high accuracy becomes possible. The switch 181-2 works similarly for the wavelength λ2.

  In this case, since the correction of the fluctuation of the optical path in the distance measuring device 10 cannot be performed, the movable reflecting mirror 128 works less frequently than the switches 181-1 and 181-2, and is the same as in the first embodiment. Correct fluctuations.

  Next, another configuration example of the modulated light source system will be described with reference to FIG.

  FIG. 17A shows the modulated light source system shown in FIG. 1. After the modulated light source 101 emits a laser with a collimator 102, a wavelength converter 103 generates a mixture of a plurality of wavelengths. In this case, when a harmonic generator is used as the wavelength converter 103, the wavelength needs to be 1 / integer, and the usable wavelength is limited. If the sum frequency / difference frequency generator is used, the degree of freedom of wavelength selection increases, but there is a problem that the axis adjustment of the two lasers becomes complicated. Therefore, other configurations will be described later.

  In FIG. 17B, two modulated light sources 101 and 101 ″ having different wavelengths are prepared. If a laser diode is used for 101 and 101 ″, a simple light source can be obtained. If λ1 and λ2 are used as far as possible from each other, the difference in the temperature dependence of the refractive index is large. Therefore, the value of parameter A used for correction becomes small, and the measurement accuracy can be increased. For example, when a Si photodiode is used as a detector, it is preferable to use one having a wavelength of about 400 nm and about 800 to 1100 nm as far as possible within a high sensitivity range of the detector. There are many photodiodes used in the optical communication band, and wavelengths around 1550 nm and around 1300 nm are also effective choices for λ1 or λ2. The modulated light sources 101 and 101 "selected from these wavelengths are intensity-modulated by signals from the same oscillator 100. Light from the modulated light sources 101 and 101" is emitted from the collimators 102 and 102 ", respectively, and is a wavelength separation mirror. (Preferably dichroic mirror) 153 is combined into one beam.

  Alternatively, as shown in FIG. 17C, the light from the modulated light sources 101 and 101 ″ is output from the collimator 102 after being coupled to a single fiber by an optical fiber coupler (preferably a WDM coupler) 174.

  Alternatively, as shown in FIG. 17 (d), these light sources 101, 101 ″ are used without being modulated, and these output lights are coupled by an optical fiber coupler (preferably a WDM coupler) 174. The modulator 175 may be the AOM or EOM mentioned in the description of the embodiment of Fig. 1, but may be an EA modulator (Electric Abolition Modulator) that has less wavelength dependency in the modulation characteristics. As another configuration, after the light from the single laser light source 101 is emitted from the collimator 102, the light is converted into light having a plurality of wavelengths mixed by the wavelength converter 103, and this is modulated by the modulator 175. The collimator 102 may be positioned when the element such as the wavelength converter 103 is an optical fiber input / output type. Note that the order of the meter 102 and the wavelength converter 103 is reversed, and the modulator 175 of FIGS. Note that the order between the modulators 175 is reversed.

  Next, a configuration example of the distance measuring apparatus 10 in the case where the wavelength converter (light receiver) is shared between λ1 and λ2 will be described with reference to FIG. The basic configuration is the same as that of the embodiment described with reference to FIG. 1, except that the reference light photoelectric converters (light receivers) 111R1 and 111R2, the filters 112R1 and 111R2, and the measurement light photoelectric converter (light receiver) 111M1. 111M2 and filters 112M1 and 111M2 are combined into a reference light receiver 111R and filter 112R, and a measurement light receiver 111M and filter 112M, respectively. The controller 162 controls the wavelength selection filter 182 to switch between λ1 and λ2. Although the configuration shown in FIG. 17A is included in FIG. 18 as the multi-wavelength modulated light source, it goes without saying that the configuration shown in FIGS. 17B to 17E may be replaced. The controller 162 operates the phase meter 113, the crosstalk corrector 163, the origin corrector 164, and the distance calculation circuit 114 in synchronization with the switching of the wavelength selection filter 182, and sets the distances D1 and D2 corresponding to the wavelengths λ1 and λ2. It is possible to accurately measure each of them and calculate an accurate distance in which the influence of the change in the refractive index of the atmosphere is corrected.

  Finally, a processing system having a three-dimensional shape evaluation device that evaluates a three-dimensional shape using the measurement result obtained by the shape measuring device according to the present invention, and adjusting the processing conditions of the processing device using the three-dimensional shape evaluation result. 19 will be used for explanation.

  The processing system shown in FIG. 19 includes shape measuring devices 11-1 and 11-2, a three-dimensional shape evaluation device 13, and a processing device 14.

  Reference numerals 11-1 and 11-2 denote solid shape measuring apparatuses according to the present invention. As described above, if necessary, one or a plurality of three-dimensional shape measuring devices are installed around the measurement object 12, and the measurement light 20-1 and 20-2 are scanned to obtain the three-dimensional shape of the measurement object 12. To do. The measurement data from these three-dimensional shape measuring devices are collected by the three-dimensional shape evaluation 13 and the deviation between the three-dimensional data and the design value is evaluated with high accuracy as the three-dimensional data of the entire measurement object 12.

  At this time, the three-dimensional shape evaluation device 13 also controls the measurement object feeding device 190 to operate the three-dimensional shape measuring device 11 in synchronization with the feeding. In such a configuration, the scanning of the measuring light 20 is set in a direction substantially orthogonal to the feeding of the measuring object 12, so that the three-dimensional shape measuring device 13 has a one-dimensional cross-sectional shape measuring function by simple uniaxial laser scanning. Together with the feeding of the measurement object 12, it is possible to measure the three-dimensional shape of the measurement object.

  Further, in the example of FIG. 9, there was no explanation for returning the measurement object 12 that came out of the processing device 14 to the processing device, but in this example, by returning to the processing device 14 again after the measurement by the three-dimensional shape evaluation device 13, Using the measured shape data of the measurement object 12, the additional rolling / forging amount, that is, the instruction data indicating how many mm additional rolling / forging results in a desired shape is obtained from the three-dimensional shape evaluation device 13. It becomes possible to perform high-precision processing by passing it to the processing device 14.

DESCRIPTION OF SYMBOLS 10 Distance measuring device, 11 Shape measuring device, 12 Measurement object, 13 Three-dimensional shape evaluation device, 14 Processing device, 20 Measuring light, 21 Position of measuring light at the time of correction data acquisition, 22 Auxiliary target for acquisition of correction data, 100 oscillator, 101 modulation light source, 101 ′ optical comb laser, 102 collimator, 103 wavelength converter, 104 beam splitter, 105 optical filter, 106 projection / detection lens, 110 wavelength separation coupler, 110M wavelength separation mirror for measurement light, 110R reference light Wavelength separation mirror, 111M1 λ1 measuring light photoelectric converter, 111M2 λ2 measuring light photoelectric converter, 111R1 λ1 reference light photoelectric converter, 111R2 λ2 reference light photoelectric converter, 112M1 λ1 measuring light frequency filter 112M2 λ2 Frequency filter for measurement light, 112R1 λ1 reference light circumference Number filter, frequency filter for 112R2 λ2 reference light, phase meter for 113-1 λ1, phase meter for 113-2 λ2, 114 distance calculation circuit, fiber collimator for 115M measurement light, fiber collimator for 115R reference light, 116M for measurement light Wavelength separation coupler (WDM coupler), 116R Wavelength separation coupler for reference light (WDM coupler), 117M1 λ1 measurement light electro-optic modulator, 117M2 λ2 measurement light electro-optic modulator, 117R1 λ1 reference light electro-optic modulator, 117R2 Electro-optic modulator for λ2 reference light, 118 frequency mixer, 119 beat extraction frequency filter, 120 correction arithmetic circuit, 128 movable reflection mirror, 129 fiber coupler, 130 optical amplifier, 131 collimator, 132 collimator, 133-1 for λ1 Fiber coupler, 133 2 Fiber coupler for λ2, 134-1 Fiber coupler for λ1, 134-2 Fiber coupler for λ2, Reference mirror for 135-1 λ1, Reference mirror for 135-2 λ2, 136-1 Fiber coupler for λ1, 136-2 λ2 Fiber Coupler, 137-1 Fiber for λ1, 137-1 Fiber for λ2, 138-1 Reference Optical Fiber for λ1, 138-2 Reference Optical Fiber for λ2, 139-1 Fiber Coupler for λ1, 139-2 Fiber for λ2 Coupler, 140-1 λ1 frequency multiplier, 140-2 λ2 frequency multiplier, 141-1 λ1 AD converter, 141-2 λ2 AD converter, 150 beam scanning mirror, 151 beam scanning mirror, 152 heating tube, 153 Wavelength separation mirror, 154 Receiver / spectrometer 159 High-speed beam switching 160, optical fiber coupler, 160-1 fiber coupler for λ1, 160-2 fiber coupler for λ2, 161 light (fiber) switch, 161-1 light (fiber) switch for λ1, 161-2 light (fiber) switch for λ2 , 162 controller, 163 crosstalk corrector, 164 origin corrector, 165 circulator, 166 circulator, 170 laser absorber, 171 laser reflector, 172 optical chopper, 174 optical fiber coupler (WDM coupler), 175 modulator, 181- 1 λ1 signal switcher, 181-2 λ2 signal switcher, 182 wavelength selection filter, 190 feeder

Claims (18)

A modulation optical system for irradiating multi-wavelength laser light;
A beam splitter for dividing the multi-wavelength laser light;
A first light receiver for photoelectrically converting the measurement light obtained by irradiating an object with the first beam divided by the beam splitter and detecting it as a measurement signal for each wavelength;
A second light receiver that photoelectrically converts a second beam different from the first beam divided by the beam splitter for each wavelength and detects it as a reference signal;
A calculation unit that detects a relative phase between the measurement signal detected by the first light receiver and the reference signal detected by the second light receiver, and obtains the distance of the measurement optical path based on the detected relative phase; A distance measuring device comprising: In claim 1,
The optical system is
Multi-wavelength laser generating means for combining a plurality of laser beams having different wavelengths or converting a single-wavelength laser beam into a multi-wavelength laser beam to generate a multi-wavelength laser beam, and the multi-wavelength laser A first optical system having a modulation light source or a modulator that modulates a laser beam input to the generation unit or a laser beam output from the multi-wavelength laser generation unit with a signal from the same oscillator, or
Multi-wavelength laser generation that combines laser light from multiple mode-locked lasers with different wavelengths or wavelength-converts laser light from one mode-locked laser using a wavelength converter to generate multi-wavelength laser light A distance measuring device comprising a second optical system having means. In claim 1,
The distance measuring device, wherein the second light receiver performs photoelectric conversion without irradiating the object with the second beam and detects it as a reference signal. In claim 1,
The arithmetic unit detects a relative phase between the measurement signal and the reference signal, detects a distance for each wavelength using the detected relative phase, and obtains a distance of a measurement optical path. apparatus. In claim 1,
The distance measuring device further comprises temperature estimating means for detecting radiation light from the object and estimating the temperature of the object. In claim 1,
With an optical path switch,
Switching from the state in which the measurement light is applied to the object, at least a state in which the measurement light is not directly applied to the object and returned directly to the first light receiver, and a state in which the measurement light is absorbed without being applied to the object A distance measuring device that creates a state and calibrates the device. In claim 6,
The optical path switch includes a chopper, a movable mirror, or an optical switch. A distance measuring device according to any one of claims 1 to 7,
Furthermore, a shape measuring apparatus comprising a deflection optical system that changes the direction of the laser beam divided by the beam splitter. A distance measuring device according to any one of claims 1 to 7,
Furthermore, a shape measuring device provided with a deflection optical system that changes the direction of the laser beam divided by the beam splitter;
A shape evaluation device for evaluating the measurement result by the shape measurement device;
A machining apparatus that determines a machining condition using an evaluation result obtained by the shape evaluation apparatus. A first step of irradiating multi-wavelength laser light;
A second step of dividing the multi-wavelength laser light;
A third step of photoelectrically converting the measurement light obtained by irradiating the object with the divided first beam for each wavelength and detecting it as a measurement signal;
A fourth step of photoelectrically converting a second beam different from the divided first beam for each wavelength and detecting it as a reference signal;
A distance measurement method comprising: a fifth step of detecting a relative phase between the measurement signal and the reference signal and obtaining a distance of a measurement optical path based on the detected relative phase. In claim 10,
The laser beam irradiation in the first step is
A first method for wavelength-converting a single-wavelength laser beam modulated by a signal from the same oscillator into a multi-wavelength laser beam;
A second method of performing wavelength conversion of unmodulated single-wavelength laser light into multi-wavelength laser light and then modulating it with a signal from the same oscillator;
A third method for combining laser beams of different single wavelengths modulated by signals from the same oscillator;
A fourth method of combining unmodulated laser beams of different single wavelengths and then modulating them with a signal from the same oscillator, and combining laser beams of a plurality of mode-locked lasers of different wavelengths, or one mode A distance measuring method comprising: performing wavelength conversion of a laser beam of a lock laser using a wavelength converter to generate a multi-wavelength laser beam. In claim 10,
In the fourth step, the second beam is photoelectrically converted without irradiating the object and detected as a reference signal. In claim 10,
In the fifth step, the relative phase between the measurement signal and the reference signal is detected, the distance for each wavelength is detected using the detected relative phase, and the distance of the measurement optical path is obtained. Measuring method. In claim 10,
Furthermore, the distance measuring method characterized by including the 6th process of estimating the temperature of a target object by detecting the emitted light from this target object. In claim 10,
Switching from the state in which the measurement light is applied to the object, at least a state in which the measurement light is not directly applied to the object and returned directly to the first light receiver, and a state in which the measurement light is absorbed without being applied to the object A distance measuring method comprising a seventh step of creating one state and calibrating the apparatus. In claim 15,
The optical path switching is performed by a chopper, a movable mirror, or an optical switch. A distance measuring method according to any one of claims 11 to 16, comprising:
The shape measuring method further includes an eighth step of measuring the shape by changing the direction of the laser beam divided by the beam splitter. A distance measuring method according to any one of claims 11 to 16, comprising:
And an eighth step of measuring the shape by changing the direction of the laser beam divided by the beam splitter;
A ninth step of evaluating the measurement result by the shape measuring device;
A tenth step of determining a processing condition using a result of the evaluation.

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