JP7004947B2 - Measuring device and measuring method - Google Patents

Description

The present invention relates to a measuring device and a measuring method for measuring a magnetic field and a distance (position, shape, dimensions, vibration, etc.) with respect to a measurement object having a magnetic field.

Conventionally, a shape measuring device that measures the shape and dimensions of an object to be measured by using a non-contact probe or a contact probe is known. In recent years, there has been an increasing demand for measuring the shape and the like of a measurement object having a magnetic field such as a magnet used in various motors. When the object to be measured has a magnetic field as described above, it may be required to measure the magnetic field in addition to the shape and the like.

Patent Document 1 discloses a magnetic field measuring device that measures a magnetic field of a magnetic transfer film by receiving measurement light transmitted through a magnetic transfer film that exhibits a magneto-optical effect (Faraday effect). In Patent Document 2, a measurement object exhibiting a magneto-optic effect is irradiated with linearly polarized light of multicolored light, and the reflected light is received to measure the wavelength dependence of the angle change of the polarizing surface of the reflected light. A change spectrum device is disclosed. Patent Document 3 discloses a magnetic sensor that measures a magnetic field of a measurement object using a Hall element.

Japanese Unexamined Patent Publication No. 2017-133862 Japanese Unexamined Patent Publication No. 2013-137209 Japanese Unexamined Patent Publication No. 2008-15154

When measuring the shape of a measurement object having a magnetic field and measuring the magnetic field, it is desirable to perform these at the same time. At this time, in the shape measuring device using the non-contact probe, the measurement light (laser light, etc.) is sequentially irradiated to a plurality of measurement points of the measurement object, and the reflected light of the measurement light is received at each measurement point. Based on the result, the shape of the object to be measured is measured by detecting the distance from the predetermined reference position to each measurement point. However, this type of shape measuring device cannot measure the magnetic field of the object to be measured at the same time.

Similarly, a shape measuring device using a contact-type probe cannot simultaneously measure the magnetic field of an object to be measured. Furthermore, in this type of shape measuring device, since a part of the probe is made of metal, when the object to be measured has a strong magnetic field, the effect of this magnetic field (that is, attractive force) deteriorates the accuracy of shape measurement. There is also a problem.

On the other hand, by using the various devices disclosed in the above patent documents for measuring the magnetic field of the object to be measured, the magnetic field of the object to be measured can be measured, but the shape and the like of the object to be measured can be measured at the same time. Can't.

Therefore, it is conceivable to individually measure the shape of the object to be measured by a non-contact shape measuring device and the magnetic field of the object to be measured by using various devices disclosed in the above patent documents. .. However, in this case, the positions of the measurement points of the distance of the measurement object by the non-contact shape measuring device and the measurement points of the magnetic field of the measurement object by the devices of each patent document do not match. Further, for example, even if a magnetic measurement sensor (Hall element, etc.) is separately provided near the probe of the non-contact shape measuring device, the positions of the two are not the same, so that the measurement point of the distance and the magnetic field in the measurement object are not the same. The problem that the measurement points of are not the same remains.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a measuring device and a measuring method capable of simultaneously measuring the distance and the magnetic field of a measuring point of a measuring object.

The measuring device for achieving the object of the present invention includes a light source unit that emits linear polarization, an optical division unit that divides the linear polarization emitted from the light source unit into measurement light and reference light, and an optical division unit. A light emitting unit that emits the divided measurement light toward the measurement point of the object to be measured, a reflection unit that reflects the reference light divided by the optical division unit, and a measurement light reflected at the measurement point. Light detection that detects the interference light output from the interference light output unit and the interference light output unit that divides and outputs the interference light between the 1 reflected light and the second reflected light of the reference light reflected by the reflection unit. A unit and a polarization state detection unit that detects the polarization state of the first reflected light from the interference light output from the interference light output unit are provided.

According to this measuring device, the detection result of the interference light used for the analysis of the distance of the measurement point and the detection result of the polarization state used for the analysis of the magnetic field of the measurement point are acquired at the same time. Distance measurement and magnetic field measurement for the same measurement point of an object can be performed at the same time.

In the measuring device according to another aspect of the present invention, the light source unit outputs linearly polarized light while sweeping the wavelength. As a result, distance measurement (frequency measurement) and magnetic field measurement for the same measurement point of the object to be measured can be performed at the same time.

In the measuring device according to another aspect of the present invention, the first analysis unit that analyzes the distance from the light emitting unit to the measurement point based on the detection result of the interference light by the light detection unit, and the first analysis unit that detects the polarization state detection unit. A second analysis unit that analyzes the magnetic field at the measurement point based on the polarization state of the reflected light is provided. As a result, the distance to the same measurement point of the object to be measured and the magnetic field can be obtained at the same time.

In the measuring device according to another aspect of the present invention, the second analysis unit analyzes the car rotation angle of the first reflected light based on the polarization state of the first reflected light detected by the polarization state detection unit. A unit and a magnetic field determination unit for determining the magnetic field at the measurement point are provided with reference to the correspondence relationship showing the relationship between the car rotation angle and the magnetic field based on the analysis result of the car rotation angle analysis unit. As a result, the magnetic field at the measurement point of the object to be measured is measured.

In the measuring device according to another aspect of the present invention, the polarization state detection unit is a difference between an optical element that divides interference light into a plurality of polarizations having different polarization directions and a difference that differentially detects a plurality of polarizations divided by the optical element. It is equipped with a dynamic light detector. As a result, the difference signal used for the above-mentioned analysis of the car rotation angle can be obtained.

The measurement method for achieving the object of the present invention includes a linear polarization emission step that emits linear polarization, an optical division step that divides the linear polarization emitted in the linear polarization emission step into measurement light and reference light, and light. The measurement light emission step that emits the measurement light divided in the division step toward the measurement point of the object to be measured, the reflection step that reflects the reference light divided in the optical division step, and the measurement reflected at the measurement point. Detects the interference light output step that divides and outputs the interference light between the first reflected light of the light and the second reflected light of the reference light reflected in the reflection step, and the interference light output in the interference light output step. It has an interference light detection step for detecting the polarization state of the first reflected light from the interference light output in the interference light output step.

The measuring device and measuring method of the present invention can simultaneously measure the distance and the magnetic field of the measuring point of the object to be measured.

It is a schematic diagram of the measuring device which simultaneously measures the shape and the magnetic field of the object to be measured. It is a graph which showed an example of the time change of the wavelength of the wavelength sweep light emitted from the wavelength sweep light source. It is explanatory drawing for demonstrating the polarization state of the 1st reflected light. It is a block diagram which shows the structure of a control device. It is explanatory drawing which showed an example of calibration data. It is explanatory drawing for demonstrating the shape measurement of the object to be measured by the measuring apparatus. It is a flowchart which shows the flow of the simultaneous measurement processing with the distance and shape of the object of measurement by a measuring device, and the magnetic field of an object of measurement.

[Measuring device configuration]
FIG. 1 is a schematic view of a measuring device 10 that simultaneously measures the shape and magnetic field of a measuring object 9 such as a magnet. The measuring device 10 measures the shape (position, displacement, and dimensions of the measurement object 9) of the measurement object 9 and its measurement by measuring the distance and the magnetic field of each of the plurality of measurement points 9a of the measurement object 9 in a non-contact manner. The magnetic field at each point 9a is measured.

The measuring device 10 includes a wavelength sweeping light source 11, a splitter 12, a fiber coupler 13, a first fiber connector 14A, a first collimator 15A, a second fiber connector 14B, and a second collimator 15B. An optical fiber cable F, which is an optical path to be connected, a mirror 17 (reflecting mirror), an optical detector 20, a polarizing beam splitter 21, a differential optical detector 22, and a control device 25 are provided.

The wavelength sweep light source 11 is connected to the polarizing element 12 via an optical fiber cable F, and together with the polarizing element 12, constitutes a light source unit of the present invention. The wavelength sweep light source 11 sweeps the wavelength to the splitter 12 via the optical fiber cable F while changing the wavelength in a constant wavelength sweep cycle (constant wavelength sweep frequency) and a constant wavelength band, for example, in a sinusoidal manner with the passage of time. Emit light.

FIG. 2 is a graph showing an example of time change of the wavelength of the wavelength sweep light emitted from the wavelength sweep light source 11. Here, the horizontal axis of the graph of FIG. 2 is the elapsed time t, and the vertical axis is the wavelength λ of the wavelength sweep light emitted from the wavelength sweep light source 11. As shown in FIG. 2, the wavelength sweep light source 11 emits wavelength sweep light whose wavelength changes in a sine wave shape in a predetermined wavelength band at each predetermined wavelength sweep cycle.

Returning to FIG. 1, the polarizing element 12 is connected to the wavelength sweep light source 11 and the fiber coupler 13 via the optical fiber cable F. The splitter 12 converts the wavelength sweep light input from the wavelength sweep light source 11 into P-polarized AL, which is linearly polarized light, and outputs the light to the fiber coupler 13. In the present embodiment, the P-polarized AL is any linear polarized light parallel to the light incident plane of the object 9 to be measured. As a result, the wavelength sweep light source 11 and the polarizing element 12 output the wavelength sweeped P-polarized aluminum AL to the fiber coupler 13.

The fiber coupler 13 is connected to the first fiber connector 14A, the second fiber connector 14B, the optical detector 20, and the polarized beam splitter 21, respectively, via the optical fiber cable F. The fiber coupler 13 divides (divides) the P-polarized AL input from the polarizing element 12 via the optical fiber cable F into the measurement light ML and the reference light RL at a constant ratio. Therefore, the fiber coupler 13 functions as the optical dividing unit of the present invention when the P-polarized AL is input. Then, the fiber coupler 13 outputs the measurement optical ML to the first fiber connector 14A via the optical fiber cable F, and outputs the reference optical RL to the second fiber connector 14B via the optical fiber cable F.

As the fiber coupler 13 and the optical fiber cable F connecting each part, a cable having a polarization holding function is used for measuring the car rotation angle φ _Kerr (see FIG. 4) by the magnetic car effect described later.

The first fiber connector 14A connects the optical fiber cable F connected to the fiber coupler 13 and the optical fiber cable F connected to the first collimeter 15A with low optical loss. Further, the second fiber connector 14B connects the optical fiber cable F connected to the fiber coupler 13 and the optical fiber cable F connected to the second collimator 15B with low optical loss. As a result, the measurement optical ML input to the first fiber connector 14A is input to the first collimator 15A via the optical fiber cable F. Further, the reference optical RL input to the second fiber connector 14B is input to the second collimator 15B via the optical fiber cable F.

The first collimator 15A corresponds to the light emitting portion of the present invention. For example, the measurement light ML input from the optical fiber cable F is converted into parallel light or the measurement light ML is condensed to obtain the measurement light ML. The light is emitted toward an arbitrary (desired) measurement point 9a of the measurement object 9. Here, the distance L ₁ is the distance between the first collimator 15A and the measurement point 9a of the measurement object 9.

A part or all of the measurement light ML emitted toward the measurement object 9 is reflected toward the first collimator 15A at the measurement point 9a of the measurement object 9. As a result, the first reflected light BL1 which is the reflected light of the measurement light ML reflected by the measurement object 9 is incident on the first collimator 15A. The first reflected light BL1 incident on the first collimator 15A is input to the fiber coupler 13 via the first fiber connector 14A and each optical fiber cable F.

FIG. 3 is an explanatory diagram for explaining the polarization state of the first reflected light BL1. As shown in FIG. 3, the measurement light ML incident on the measurement point 9a of the measurement object 9 is the light obtained by dividing the P-polarized AL as described above. Here, the object 9 to be measured has a magnetic field (magnetized). Therefore, when the measurement light ML (P-polarized AL) is incident on the measurement point 9a, the first reflected light BL1 reflected at the measurement point 9a is shown by the magnetic car effect (pole car effect, vertical car effect, etc.). As indicated by the reference numeral E in the inside, the polarization is elliptically polarized, and the main axis d2 thereof rotates from the polarization direction d1 of the measurement light ML (P polarization AL). The rotation angle of the spindle d2 with respect to the polarization direction d1 is the car rotation angle φ _Kerr (see FIG. 4).

Returning to FIG. 1, the second collimator 15B converts, for example, the reference light RL input from the optical fiber cable F into parallel light or condenses the reference light RL, and emits the reference light RL toward the mirror 17. .. Here, the distance L ₂ is the distance between the second collimator 15B and the mirror 17. In this embodiment, the optical path length of the measured light ML from the fiber coupler 13 to the first collimator 15A and the optical path length of the reference light RL from the fiber coupler 13 to the second collimator 15B are set to be equal.

The mirror 17 corresponds to the reflecting portion of the present invention, and reflects the reference light RL emitted from the second collimator 15B. As a result, the second reflected light BL2, which is the reflected light of the reference light RL reflected by the mirror 17, is incident on the second collimator 15B. The second reflected light BL2 incident on the second collimator 15B is input to the fiber coupler 13 via the second fiber connector 14B and each optical fiber cable F. Instead of the mirror 17, various reflecting portions such as a corner cube prism may be used.

The fiber coupler 13 has a first reflected light BL1 input from the first fiber connector 14A via the optical fiber cable F and a second reflected light BL2 input from the second fiber connector 14B via the optical fiber cable F. Combine waves. Then, the fiber coupler 13 divides the combined interference light SL (combined light) at an arbitrary ratio, and divides the divided interference light SL into the optical detector 20 and the polarizing beam splitter 21 via the optical fiber cable F, respectively. Output. Therefore, the fiber coupler 13 functions as the interference light output unit of the present invention when the first reflected light BL1 and the second reflected light BL2 are input.

The photodetector 20 corresponds to the photodetector of the present invention, and for example, a CCD (Charge Coupled Device) type or CMOS (complementary metal oxide semiconductor) type image sensor or a silicon photodiode is used. The optical detector 20 receives the interference light SL input (incident) from the fiber coupler 13 via the optical fiber cable F, converts and amplifies the interference light SL into an interference signal SG which is an electric signal, and controls the control device 25. Output to. It is preferable that the photodetector 20 has a response speed sufficiently faster than the wavelength sweep speed [displacement of the object 9 to be measured with time when it is vibrating (displaced)], for example, a response speed of 1 MHz or more.

The polarization beam splitter 21 and the differential photodetector 22 correspond to the polarization state detection unit of the present invention, and are used for detecting the polarization state of the interference light SL (first reflected light BL1). The polarization state referred to here is the intensity ratio (intensity difference) of each polarization when the interference light SL is divided (decomposed) into a plurality of polarizations having different polarization directions. Specifically, in the present embodiment, the difference signal DG described later used for the analysis of the above-mentioned car rotation angle φ _Kerr (see FIG. 4) is detected as the polarization state. The polarization state may include the car rotation angle φ _Kerr itself.

The polarization beam splitter 21 corresponds to the optical element of the present invention, and the interference light SL input from the fiber coupler 13 via the optical fiber cable F is subjected to a plurality of polarizations having different polarization directions, that is, P-polarized CL1 and S. Split (decompose) into polarized CL2. The P-polarized CL1 is substantially the same as the P-polarized AL. Further, the S-polarized CL2 of the present embodiment is linearly polarized light orthogonal to the P-polarized CL1 (P-polarized AL). Then, the polarization beam splitter 21 outputs the divided P-polarized CL1 and S-polarized CL2 to the differential photodetector 22 via the optical fiber cable F, respectively.

Here, the first reflected light BL1 is elliptically polarized due to the magnetic car effect, whereas the second reflected light BL2 remains P-polarized AL. Therefore, the P-polarized CL1 is a combination of the P-polarized component of the first reflected light BL1 and the second reflected light BL2, and the S-polarized CL2 is the S-polarized component of the first reflected light BL1. The intensity ratio (intensity difference) of the P-polarized component and the S-polarized component of the first reflected light BL1 changes according to the size and direction of the car rotation angle φ _Kerr (see FIG. 4). 2 The intensity of the reflected light BL2 is constant. Therefore, the intensity ratio (intensity difference) of the P-polarized CL1 and the S-polarized CL2 is an index indicating the car rotation angle φ _Kerr of the first reflected light BL1.

The differential photodetector 22 differentially detects the P-polarized CL1 and the S-polarized CL2 that are individually input via the optical fiber cable F, and is a differential signal proportional to the above-mentioned car rotation angle φ _Kerr (see FIG. 4). The DG is output to the control device 25. Although not shown, the differential photodetector 22 includes a first photodetector that detects P-polarized CL1, a second photodetector that detects S-polarized CL2, a first detector, and a second detector. A differential amplifier circuit connected to is provided. The differential photodetector 22 is not particularly limited to the above configuration as long as the difference signal DG of the P-polarized CL1 and the S-polarized CL2 can be detected.

The control device 25 is, for example, an arithmetic processing device such as a personal computer, and controls the operation of each part of the measuring device 10 such as the wavelength sweep light source 11, the photodetector 20, and the differential photodetector 22. Further, the control device 25 analyzes the interference signal SG input from the photodetector 20 and the difference signal DG input from the differential photodetector 22, and position information (distance) of the measurement point 9a of the measurement object 9. L ₁ etc.) and the magnetic field at the measurement point 9a are determined respectively.

[Control device configuration]
FIG. 4 is a block diagram showing the configuration of the control device 25. The control device 25 is connected to a display unit 30 that displays various analysis results such as position information and a magnetic field of the measurement point 9a of the measurement object 9, and a storage unit 31 that stores these various analysis results.

The arithmetic processing circuit including the CPU (central processing unit) or FPGA (field-programmable gate array) (not shown) of the control device 25 executes the control program (not shown) to execute the measurement control unit 33 and the first analysis unit. It functions as 34 and the second analysis unit 35.

The measurement control unit 33 controls the emission of the wavelength sweep light by the wavelength sweep light source 11, the output of the interference signal SG by the photodetector 20, the output of the difference signal DG by the differential photodetector 22 and the like.

The first analysis unit 34 acquires the interference signal SG from the photodetector 20, analyzes the interference signal SG, and derives the distance L1 at the measurement _point 9a of the measurement object 9. Further, when the measurement object 9 is vibrating, the first analysis unit 34 also derives the frequency (displacement) of the measurement object 9 (measurement point 9a). The method of analyzing the interference signal SG to derive the distance L ₁ and the frequency is described in known techniques (Japanese Patent Laid-Open Nos. 2017-167065, 2016-24086, and 2016-17919). Therefore, the details thereof will be omitted. Then, the first analysis unit 34 transmits the position information such as the distance L1 of the measurement point 9a of the measurement object ₉ and the frequency (when the measurement object 9 is vibrating) to the display unit 30 and the storage unit 31. Output each.

The second analysis unit 35 analyzes the difference signal DG input from the differential photodetector 22 to derive the magnetic field (magnetic field strength) of the measurement point 9a of the measurement object 9. The magnetic flux in the present specification also includes the magnetic flux density. The second analysis unit 35 has a car rotation angle analysis unit 36 and a magnetic field determination unit 37.

The car rotation angle analysis unit 36 acquires the difference signal DG from the differential photodetector 22, and analyzes the difference signal DG to analyze the car rotation angle of the first reflected light BL1 at the measurement point 9a of the measurement object 9. Derivation of φ. As described above, since the difference signal DG is proportional to the car rotation angle φ _Kerr , the car rotation angle φ _Kerr can be derived from the difference signal DG.

Hereinafter, an example of a method for deriving the car rotation angle φ _Kerr will be described. The car rotation angle φ _Kerr is expressed by the light measurement intensity as shown in the following equation [Equation 1].

In the above equation [Equation 1], the I _Linier is a linear polarization component of the measurement light ML (incident light), and the photodetector 20 is used when the measurement target 9 (for example, a mirror) having a zero magnetic field is the measurement target. It is obtained by measuring the signal strength of the detected interference signal SG in advance. The I _Linier may be set to a fixed value such as 0.5.

Further, in the above equation [Equation 1], the IR _C is the intensity corresponding to the clockwise circular polarization, and the _ILC is the intensity corresponding to the counterclockwise circular polarization. In this embodiment, one of _IRC and _ILC corresponds to the intensity of P-polarized CL1, and the other of _IRC and _ILC corresponds to the intensity of S-polarized CL2. Then, the correspondence between the difference signal DG [difference in signal intensity between P-polarized CL1 and S-polarized CL2 (signal intensity ratio)] and _IRC and _ILC is determined by the type of object 9 to be measured and the wavelength sweep light (measurement light). By measuring in advance for each intensity of ML), _IRC and _ILC can be determined from the difference signal DG.

Therefore, the car rotation angle analysis unit 36 substitutes the I _Linier obtained by measuring in advance and the I _RC and I _LC obtained from the difference signal DG into the above equation [Equation 1] to measure the measurement point 9a. The car rotation angle φ _Kerr of the first reflected light BL1 is calculated for each, and the calculation result is output to the magnetic field determination unit 37.

Since the method of analyzing the car rotation angle φ _Kerr using the polarization beam splitter 21 and the differential photodetector 22 is a known technique (for example, Japanese Patent Application Laid-Open No. 2008-159196), the method of analyzing the car rotation angle φ _Kerr is used. Is not limited to the above method. For example, by measuring in advance the correspondence between the difference signal DG and the car rotation angle φ _Kerr for each type of the object 9 to be measured and the intensity of the wavelength sweep light (measurement light ML), the car rotation can be performed from the difference signal DG. A method of directly calculating the angle φ _Kerr may be used.

The magnetic field determination unit 37 determines the magnetic field (magnetic field strength) of the measurement point 9a reflected by the first reflected light BL1 from the car rotation angle φ _Kerr of the first reflected light BL1 input from the car rotation angle analysis unit 36. .. At this time, the magnetic field determination unit 37 determines the magnetic field using the calibration data 38.

FIG. 5 is an explanatory diagram showing an example of calibration data 38. The magnetic field at the measurement point 9a and the car rotation angle φ _Kerr of the first reflected light BL1 reflected at the measurement point 9a are constant according to the type of the object to be measured 9 and the intensity of the wavelength sweep light (measurement light ML). Have a relationship of. Therefore, as shown in FIG. 5, the calibration data 38 measures the correspondence between the magnetic field and the car rotation angle φ _Kerr in advance for each type of the object to be measured 9 and the intensity of the wavelength sweep light (measurement light ML). It was obtained. The calibration data 38 created for each type of measurement object 9 and for each wavelength sweep light intensity is stored in a database (an external database is also possible), an external server, or a storage unit 31 (not shown). ..

Returning to FIG. 4, the magnetic field determination unit 37 stores calibration data 38 corresponding to both the type of the object to be measured 9 and the intensity of the wavelength sweep light (measurement light ML) according to the selection operation by the user (not shown). ) Etc. As a result, the magnetic field determination unit 37 determines the magnetic field at the measurement point 9a by referring to the calibration data 38 based on the car rotation angle φ _Kerr input from the car rotation angle analysis unit 36. Then, the magnetic field determination unit 37 outputs the magnetic field determination result of the measurement point 9a to the display unit 30 and the storage unit 31, respectively.

In this way, the measuring device ₁₀ can simultaneously measure the position information such as the distance L1 of the measurement point 9a of the measurement object 9 and the magnetic field.

FIG. 6 is an explanatory diagram for explaining the shape measurement of the measurement object 9 by the measuring device 10. As shown in FIG. 6, the measuring device 10 (first collimator 15A) and the measuring object 9 can move relative to each other automatically or manually along the surface (outer surface) of the measuring object 9 (posture of the first collimator 15A). (Including changes). Therefore, by moving both relative to each other, the surface of the object to be measured 9 can be scanned by the measurement light ML. As a result, the output of the interference light SL of the first reflected light BL1 and the second reflected light BL2, the output and analysis of the interference signal SG, the output of the difference signal DG, and the output of the difference signal DG for each of the plurality of measurement points 9a in the measurement object 9. Analysis and can be done. Thereby, the position information (distance L1, etc.) and the magnetic field of _each of the plurality of measurement points 9a of the measurement object 9 can be measured.

Returning to FIG. 4, in the measurement data 40 in the storage unit 31, position information (distance L1, etc.) and _a magnetic field are stored in association with each measurement point 9a of the measurement object 9. Although not shown, information on the relative movement amount and the relative movement direction between the measuring device 10 (first collimator 15A) and the measurement object 9 for each measurement point 9a is also known or measured in advance. Therefore, for example, the first analysis unit 34 may measure the object 9 based on the distance L1 for _each measurement point 9a, the relative movement amount and the relative movement direction for each measurement point 9a (the posture of the first collimeter 15A). The shape (dimensions) of can be measured. The shape measurement result of the measurement object 9 is also displayed on the display unit 30 and stored in the storage unit 31.

[Action of measuring device]
Next, the operation of the measuring device 10 having the above configuration will be described with reference to FIG. 7. FIG. 7 is a flowchart showing the flow of simultaneous measurement processing (measurement method) of the distance L1 and the shape of the measurement object 9 by the measuring device ₁₀ and the magnetic field of the measurement object 9.

When the user sets the measurement object 9 having a magnetic field at a predetermined measurement position and then performs a measurement start operation on the operation unit (not shown) of the measurement device 10, the measurement control unit 33 of the control device 25 sweeps the wavelength. The light source 11, the photodetector 20, and the differential photodetector 22 are operated. Further, when the user selects the type of the measurement object 9 and the intensity of the wavelength sweep light (measurement light ML), the magnetic field determination unit 37 corresponds to both the type of the measurement object 9 and the intensity of the wavelength sweep light. The calibrated data 38 is acquired from a database or the like.

In response to the user's measurement start operation, the wavelength sweep light source 11 emits wavelength sweep light (step S1). This wavelength sweep light is input to the splitter 12 via the optical fiber cable F, and is converted into P-polarized AL by the splitter 12 (step S2). This P-polarized AL is output from the polarizing element 12 to the fiber coupler 13 via the optical fiber cable F. In addition, step S1 and step S2 correspond to the linear polarization emission step of this invention.

The P-polarized AL input to the fiber coupler 13 is divided into the measurement light ML and the reference light RL by the fiber coupler 13 (step S3, corresponding to the optical division step of the present invention). Then, the measurement light ML is input to the first collimator 15A via the first fiber connector 14A and the like. On the other hand, the reference optical RL is input to the second collimator 15B via the second fiber connector 14B or the like.

The measurement light ML input to the first collimator 15A is emitted from the first collimator 15A toward the measurement object 9 (step S4, corresponding to the measurement light emission step of the present invention). Then, the first reflected light BL1 of the measurement light ML reflected at the first measurement point 9a of the measurement object 9 is incident on the first collimator 15A. At this time, since the object 9 to be measured has a magnetic field, the measurement light ML is linearly polarized (P-polarized AL), whereas the first reflected light BL1 is elliptically polarized due to the magnetic car effect.

On the other hand, the reference light RL input to the second collimator 15B is emitted from the second collimator 15B toward the mirror 17 and reflected by the mirror 17 (step S5, corresponding to the reflection step of the present invention). As a result, the second reflected light BL2 is incident on the second collimator 15B.

The first reflected light BL1 input to the first collimator 15A is input to the fiber coupler 13 via the first fiber connector 14A and the like. Further, the second reflected light BL2 input to the second collimator 15B is input to the fiber coupler 13 via the second fiber connector 14B or the like.

Then, the first reflected light BL1 and the second reflected light BL2 input to the fiber coupler 13 are combined by the fiber coupler 13 (step S6). The combined light SL of the first reflected light BL1 and the second reflected light BL2 is divided by the fiber coupler 13 and then output to the light detector 20 and the polarized beam splitter 21 (step S7, respectively). Corresponds to the interference light output step of the present invention).

The interference light SL input to the photodetector 20 is received (detected) by the photodetector 20. As a result, the interference signal SG, which is the detection result of the interference light SL, is output from the photodetector 20 to the first analysis unit 34 of the control device 25 (step S8, corresponding to the interference light detection step of the present invention).

On the other hand, the interference light SL input to the polarizing beam splitter 21 is split into P-polarized CL1 and S-polarized CL2 in the polarizing beam splitter 21 (step S9). The divided P-polarized CL1 and S-polarized CL2 are input to the differential photodetector 22. As a result, the difference signal DG of the P-polarized CL1 and the S-polarized CL2 is detected by the differential photodetector 22, and this difference signal DG is output to the car rotation angle analysis unit 36 of the second analysis unit 35 (step S10). .. In addition, step S9 and step S10 correspond to the polarization state detection step of this invention.

By the processing from step S1 to step S10, it is used for the analysis of the interference signal SG used for the analysis of the distance L1 and the like from the _first measurement point 9a of the measurement object 9 and the magnetic field at the first measurement point 9a. The difference signal DG is acquired at the same time. That is, the distance measurement and the magnetic field measurement with respect to the same measurement point 9a of the measurement object 9 are substantially executed at the same time.

Upon receiving the input of the interference signal SG from the optical detector 20, the first analysis unit 34 analyzes the interference signal SG by a known method, and the distance L ₁ (corresponding to the first measurement point 9a of the measurement object 9) ( The position) is derived, and when the object 9 to be measured is vibrating, the frequency at the first measurement point 9a is derived (step S11). Then, the first analysis unit 34 outputs the position information such as the distance L1 and the frequency at the _first measurement point 9a to the display unit 30 and the storage unit 31, respectively.

On the other hand, the car rotation angle analysis unit 36, which receives the input of the difference signal DG from the differential photodetector 22, analyzes the difference signal DG by various known methods and rotates the car of the interference light SL (first reflected light BL1). The angle φ _Kerr is derived, and the derivation result of this car rotation angle φ _Kerr is output to the magnetic field determination unit 37 (step S12).

Then, the magnetic field determination unit 37, which receives the input of the derivation result of the car rotation angle φ _Kerr , refers to the calibration data 38 previously acquired based on this car rotation angle φ _Kerr , and obtains the magnetic field of the first measurement point 9a. Determine (step S13). Next, the magnetic field determination unit 37 outputs the magnetic field determination result of the first measurement point 9a to the display unit 30 and the storage unit 31, respectively.

The position information such as the distance L1 output from the _first analysis unit 34 and the magnetic field output from the magnetic field determination unit 37 are displayed on the display unit 30 in a state of being associated with the first measurement point 9a. At the same time, it is stored in the measurement data 40 in the storage unit 31 (step S14).

Next, after the measuring device 10 (first collimator 15A) and the measuring object 9 are relatively moved, the above-described processes from step S1 to step S14 are repeatedly executed (step S15). As a result, the position information (distance L ₁ , etc.) and the magnetic field corresponding to the second measurement point 9a of the measurement object 9 are displayed on the display unit 30 and stored in the measurement data 40 in the storage unit 31. To.

Similarly, as described above, each time the measuring device 10 (first collimator 15A) and the measuring object 9 are moved relative to each other until the entire measurement range on the surface of the measuring object 9 is scanned by the measuring light ML. The processes from step S1 to step S14 are repeatedly executed (step S15). As a result, the measurement data 40 in the storage unit 31 stores the position information (distance L1, etc.) and the magnetic field in association with _each measurement point 9a within the measurement range of the measurement object 9.

Then, the first analysis unit 34 determines the shape of the object 9 to be measured (the posture of the first collimeter 15A) based on the distance L1 for _each measurement point 9a, the relative movement amount and the relative movement direction for each measurement point 9a. Dimension) is measured, and the measurement result of this shape is displayed on the display unit 30 and stored in the storage unit 31.

[Effect of this embodiment]
As described above, in the measuring device ₁₀ of the present embodiment, the position information such as the distance L1 and the magnetic field can be simultaneously measured at each measurement point 9a of the measurement object 9. Then, by this simultaneous measurement, the correspondence between the distance L1 and the like at _each measurement point 9a and the magnetic field becomes clear. Therefore, not only the shape of the object to be measured 9 but also the magnetic field (magnetic field distribution) in each part of the object 9 to be measured can be measured simultaneously and accurately. Further, since the measuring device 10 of the present embodiment performs non _- contact measurement, it is possible to simultaneously measure the distance L1 and the like (frequency, shape) and the magnetic field even in the measurement object 9 having a strong magnetic field.

[others]
The configuration of the optical system of the measuring device 10 is not limited to the configuration shown in FIG. 1 and has the same function as long as the interference light SL between the first reflected light BL1 and the second reflected light BL2 can be divided and output. It can be appropriately changed to a member or a structure having the above.

In the measuring device 10 of the above embodiment, the wavelength sweep light source 11 and the polarizing element 12 are used to emit P-polarized AL, which is linearly polarized light. The configuration is not particularly limited as long as it can be emitted. Further, instead of linear polarization such as P-polarization AL that has been wavelength-swept (that is, wavelength-swept light source 11), single-wavelength linear polarization ( _single -wavelength laser light source, etc.) capable of measuring distance L1 (displacement) can be measured. ) May be used.

In the measuring device 10 of the above embodiment, the interference light SL is divided into P-polarized CL1 and S-polarized CL2 by using the polarized beam splitter 21, but various optical elements such as a rotationally driven polarizing plate are used. The interference light SL may be divided into P-polarized CL1 and S-polarized CL2. Further, if the polarization state of the interference light SL (first reflected light BL1) can be detected, the interference light SL may be divided into a plurality of polarizations having different polarization directions by the above-mentioned various optical elements.

In the above embodiment, the fiber coupler 13 is used to separately output the interference light SL between the first reflected light BL1 and the second reflected light BL2, but other optical elements having the same function are the interference light of the present invention. It may be used as an output unit.

In the measuring device 10 of the above embodiment, the control device 25 analyzes the distance L1 and the like and the magnetic field for _each measurement point 9a, but this analysis may be performed by another device. Therefore, the measuring device of the present invention has a configuration excluding the control device 25, that is, it is used for the analysis of the interference signal SG used for the analysis of the distance L1 and the like corresponding to the measuring _point 9a and the magnetic field of the measuring point 9a. A device capable of simultaneously acquiring the difference signal DG to be obtained is also included.

9 ... Measurement target,
9a ... Measurement point,
10 ... Measuring device,
11 ... Wavelength sweep light source,
12 ... Polarizer,
13 ... Fiber coupler,
17 ... Mirror,
20 ... Photodetector,
21 ... Polarization beam splitter,
22 ... Differential photodetector,
25 ... Control device,
34 ... First Analysis Department,
35 ... Second Analysis Department,
36 ... Car rotation angle analysis unit,
37 ... Magnetic field determination unit

Claims (6)

A light source that emits linearly polarized light and
An optical dividing unit that divides the linearly polarized light emitted from the light source unit into measurement light and reference light, and
A light emitting unit that emits the measured light divided by the optical dividing unit toward the measurement point of the measurement object, and a light emitting unit.
A reflecting unit that reflects the reference light divided by the light dividing unit, and a reflecting unit.
An interference light output unit that divides and outputs the interference light between the first reflected light of the measurement light reflected at the measurement point and the second reflected light of the reference light reflected by the reflection unit.
A photodetector that detects the interference light output from the interference light output unit,
A polarization state detection unit that detects the polarization state of the first reflected light from the interference light output from the interference light output unit, and a polarization state detection unit.
A first analysis unit that analyzes the distance from the light emitting unit to the measurement point based on the detection result of the interference light by the photodetection unit.
A second analysis unit that analyzes the magnetic field at the measurement point based on the polarization state of the first reflected light detected by the polarization state detection unit.
A measuring device equipped with. The measuring device according to claim 1, wherein the light source unit outputs the linearly polarized light while sweeping the wavelength. The second analysis unit is
A car rotation angle analysis unit that analyzes the car rotation angle of the first reflected light based on the polarization state of the first reflected light detected by the polarization state detection unit.
Based on the analysis result of the car rotation angle analysis unit, the magnetic field determination unit for determining the magnetic field at the measurement point and the magnetic field determination unit with reference to the correspondence relationship showing the relationship between the car rotation angle and the magnetic field.
The measuring device according to claim 1 or 2 . The polarization state detection unit is
An optical element that divides the interference light into a plurality of polarizations having different polarization directions,
A differential photodetector that differentially detects the plurality of polarizations divided by the optical element, and
The measuring device according to any one of claims 1 to 3 . A linearly polarized light emitting step that emits linearly polarized light, and a linearly polarized light emitting step,
An optical division step that divides the linear polarization emitted in the linear polarization emission step into measurement light and reference light, and
A measurement light emission step in which the measurement light divided in the optical division step is emitted from the light emitting unit toward the measurement point of the measurement object, and a measurement light emission step.
A reflection step that reflects the reference light divided by the light division step,
An interference light output step that divides and outputs the interference light between the first reflected light of the measurement light reflected at the measurement point and the second reflected light of the reference light reflected at the reflection step.
The interference light detection step for detecting the interference light output in the interference light output step, and the interference light detection step.
A polarization state detection step for detecting the polarization state of the first reflected light from the interference light output in the interference light output step, and a polarization state detection step.
Based on the detection result of the interference light by the interference light detection step, the first analysis step of analyzing the distance from the light emitting portion to the measurement point, and
A second analysis step of analyzing the magnetic field at the measurement point based on the polarization state of the first reflected light detected in the polarization state detection step, and
Measurement method with. The second analysis step is
A car rotation angle analysis step for analyzing the car rotation angle of the first reflected light based on the polarization state of the first reflected light detected in the polarization state detection step, and a car rotation angle analysis step.
Based on the analysis result of the car rotation angle analysis step, the magnetic field determination step for determining the magnetic field at the measurement point and the magnetic field determination step with reference to the correspondence relationship showing the relationship between the car rotation angle and the magnetic field.
The measuring method according to claim 5.

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