Magnetic detection device, magnetic sensor, and magnetic detection method

Abstract

To detect a magnetic field in a biaxial direction.SOLUTION: A magnetic detection device 1 comprises a magnetic sensor 20 and a measuring device 10. The magnetic sensor 20 comprises a first transmission line 21 and a second transmission line 22. The first transmission line 21 and the second transmission line 22 are arranged in a non-parallel manner. The measuring device 10 comprises a signal generator 11 which generates a first incident wave and a second incident wave, a signal wave detector 12 detecting a first reflection wave generated due to an impedance mismatch of the first transmission line 21 and a second reflection wave generated due to an impedance mismatch of the second transmission line 22, and a control unit 13. The control unit 13 calculates a first magnetic field on the basis of the first incident wave and the first reflection wave, calculates a second magnetic field on the basis of the second incident wave and the second reflection wave, and calculates a magnetic field in a biaxial direction on the basis of the first magnetic field and the second magnetic field.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a magnetic detection device, a magnetic sensor, and a magnetic detection method.

Background Art

[0002] Conventionally, magnetic detection devices capable of detecting a magnetic field have been known. There are various configurations of magnetic detection devices.

[0003] A magnetic detection device having a linear configuration of a magnetic sensor for detecting a magnetic field is known (for example, Patent Document 1 and Patent Document 2).

[0004] Since the linear magnetic sensor has high flexibility, there is an advantage that the magnetic sensor can be freely installed according to the measurement object. Further, when using a linear magnetic sensor, there is an advantage that a magnetic field can be detected at an arbitrary position of the linear magnetic sensor.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The magnetic field detected by the magnetic detection devices described in Patent Documents 1 and 2 is a magnetic field in a direction along the longitudinal direction of the linear magnetic sensor. That is, the magnetic detection devices described in Patent Documents 1 and 2 can detect a magnetic field in a uniaxial direction.

[0007] In a magnetic detection device using a linear magnetic sensor, it is desirable to be able to detect not only a magnetic field in a uniaxial direction but also a magnetic field in a biaxial direction.

[0008] Therefore, an object of the present disclosure is to provide a magnetic detection device, a magnetic sensor, and a magnetic detection method capable of detecting a magnetic field in two axial directions.

Means for Solving the Problems

[0009] A magnetic detection device according to some embodiments is a magnetic detection device including a magnetic sensor and a measurement device. The magnetic sensor includes a first transmission line including a linear first conductor containing a magnetic material, and a second transmission line including a linear second conductor containing a magnetic material. The first transmission line and the second transmission line are arranged non-parallel to each other. The measurement device includes a signal generator that generates a first incident wave input to the first transmission line and a second incident wave input to the second transmission line, a signal detector that detects a first reflected wave generated by impedance mismatch of the first transmission line at the magnetic field application position to the magnetic sensor and a second reflected wave generated by impedance mismatch of the second transmission line at the magnetic field application position, and a control unit. The control unit calculates a first magnetic field in the direction along the first transmission line at the magnetic field application position based on the first incident wave and the first reflected wave, calculates a second magnetic field in the direction along the second transmission line at the magnetic field application position based on the second incident wave and the second reflected wave, and calculates a magnetic field in two axial directions based on the first magnetic field and the second magnetic field. According to such a magnetic detection device, it is possible to detect a magnetic field in two axial directions.

[0010] In a magnetic detection device according to an embodiment, the magnetic sensor includes a plurality of the first transmission lines connected in parallel and arranged parallel to each other, and a plurality of the second transmission lines connected in parallel and arranged parallel to each other. The plurality of the first transmission lines and the plurality of the second transmission lines may be arranged non-parallel to each other. Thereby, the resistance loss can be reduced.

[0011] In a magnetic detection device according to an embodiment, the first transmission line and the second transmission line may be any one of a coaxial cable, a parallel two-wire line, a strip line, a microstrip line, a coplanar line, and a waveguide. In this way, by using a coaxial cable for the first transmission line and the second transmission line, flexibility can be imparted to the first transmission line and the second transmission line. Further, flexibility can be imparted to the first transmission line and the second transmission line by forming a parallel two-wire line, a strip line, a microstrip line, a coplanar line, or a waveguide on a flexible substrate.

[0012] In a magnetic detection device according to an embodiment, the first transmission line includes a plurality of the first conductors, the plurality of the first conductors are connected by at least one non-magnetic material conductor, the first transmission line has a sawtooth shape, the second transmission line includes a plurality of the second conductors, the plurality of the second conductors are connected by at least one non-magnetic material conductor, the second transmission line has a sawtooth shape, and the plurality of the first conductors and the plurality of the second conductors may be arranged non-parallel to each other. Thereby, without increasing the length of the magnetic sensor in the short side direction and without reducing the sensitivity of the magnetic field in the short side direction, the range in which the magnetic sensor can detect the magnetic field can be expanded in the longitudinal direction.

[0013] In a magnetic detection device according to an embodiment, two adjacent first conductors among the plurality of the first conductors may have an overlapping region in the longitudinal direction of the magnetic sensor, and two adjacent second conductors among the plurality of the second conductors may have an overlapping region in the longitudinal direction of the magnetic sensor. Thereby, it is possible to prevent the existence of a region where the sensitivity to an external magnetic field may be low.

[0014] In a magnetic detection device according to an embodiment, the first transmission line and the second transmission line may further include a coil for applying a bias magnetic field. Thereby, the first magnetic field and the second magnetic field can be calculated at an operating point showing high linearity, small hysteresis, and high sensitivity.

[0015] Magnetic sensors according to some embodiments include a first transmission line including a linear first conductor containing a magnetic material, and a second transmission line including a linear second conductor containing a magnetic material, and the first transmission line and the second transmission line are arranged non-parallel to each other. According to such a magnetic sensor, it is possible to detect a magnetic field in two axial directions.

[0016] A magnetic detection method according to some embodiments is a magnetic detection method in a magnetic detection device including a magnetic sensor and a measuring device, the magnetic sensor includes a first transmission line including a linear first conductor containing a magnetic material, and a second transmission line including a linear second conductor containing a magnetic material, the first transmission line and the second transmission line are arranged non-parallel to each other, and the magnetic detection method includes steps of: the measuring device generating a first incident wave input to the first transmission line and a second incident wave input to the second transmission line; detecting a first reflected wave generated by impedance mismatch of the first transmission line at the magnetic field application position to the magnetic sensor and a second reflected wave generated by impedance mismatch of the second transmission line at the magnetic field application position; calculating a first magnetic field in a direction along the first transmission line at the magnetic field application position based on the first incident wave and the first reflected wave; calculating a second magnetic field in a direction along the second transmission line at the magnetic field application position based on the second incident wave and the second reflected wave; and calculating a magnetic field in two axial directions based on the first magnetic field and the second magnetic field. According to such a magnetic detection method, it is possible to detect a magnetic field in two axial directions.

Advantages of the Invention

[0017] According to the present disclosure, it is possible to provide a magnetic detection device, a magnetic sensor, and a magnetic detection method capable of detecting a magnetic field in two axial directions.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

MODE FOR CARRYING OUT THE INVENTION

[0019] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0020] FIG. 1 is a diagram showing a schematic configuration of a magnetic detection device 1 according to an embodiment. The magnetic detection device 1 includes a measuring device 10 and a magnetic sensor 20.

[0021] The magnetic sensor 20 includes a first transmission line 21, a second transmission line 22, and a substrate 23.

[0022] The first transmission line 21 is formed on the substrate 23. The second transmission line 22 is formed on the substrate 23. The first transmission line 21 and the second transmission line 22 are formed on the substrate 23 so as not to be short-circuited.

[0023] For example, the first transmission line 21 may be formed on the front surface of the substrate 23, and the second transmission line 22 may be formed on the back surface of the substrate 23. Alternatively, the first transmission line 21 may be formed on the back surface of the substrate 23, and the second transmission line 22 may be formed on the front surface of the substrate 23.

[0024] Alternatively, when the substrate 23 is a multilayer substrate, the first transmission line 21 and the second transmission line 22 may be formed on different layers of the substrate 23.

[0025] As shown in FIG. 1, the first transmission line 21 and the second transmission line 22 are arranged non-parallel to each other.

[0026] The substrate 23 is a flexible substrate. The substrate 23 may be, for example, an FPC (Flexible Printed Circuits).

[0027] The first transmission line 21 and the second transmission line 22 are linear transmission lines. The first transmission line 21 and the second transmission line 22 have a predetermined characteristic impedance. The first transmission line 21 and the second transmission line 22 may be formed on the substrate 23 as flexible coaxial cables. Further, the first transmission line 21 and the second transmission line 22 may be formed on the substrate 23 as any one of a parallel two-wire line, a strip line, a microstrip line, a coplanar line, and a waveguide.

[0028] Since the first transmission line 21, the second transmission line 22, and the substrate 23 have flexibility, the magnetic sensor 20 can be easily deformed. Due to its flexibility, the magnetic sensor 20 can be freely installed according to the shape of the measurement object.

[0029] One end of the first transmission line 21 is connected to the port P1 of the measuring device 10. The other end of the first transmission line 21 is connected to the port P2 of the measuring device 10.

[0030] One end of the second transmission line 22 is connected to the port P3 of the measuring device 10. The other end of the second transmission line 22 is connected to the port P4 of the measuring device 10.

[0031] The first transmission line 21 includes a linear first conductor 210 containing a magnetic material. The first conductor 210 functions as a signal line. The first transmission line 21 may include, in addition to the first conductor 210, a shield line composed of a copper wire or the like, and a dielectric that insulates the first conductor 210 and the shield line.

[0032] The second transmission line 22 includes a linear second conductor 220 containing a magnetic material. The second conductor 220 functions as a signal line. The second transmission line 22 may include, in addition to the second conductor 220, a shield line composed of a copper wire or the like, and a dielectric that insulates the second conductor 220 and the shield line.

[0033] The first conductor 210 and the second conductor 220 are linear conductors containing a magnetic material. The first conductor 210 and the second conductor 220 contain, for example, a magnetic material that is distributed substantially uniformly.

[0034] The first conductor 210 and the second conductor 220 may contain a soft magnetic material with a low holding force and a high magnetic permeability. The first conductor 210 and the second conductor 220 may contain, for example, an amorphous alloy or permalloy.

[0035] The amorphous alloy and permalloy contain a magnetic material with a high magnetic permeability. Therefore, the first transmission line 21 including the first conductor 210 and the second transmission line 22 including the second conductor 220 have a high circumferential magnetic permeability and axial magnetic permeability. Because the circumferential magnetic permeability and axial magnetic permeability are high, when an external magnetic field is applied, the impedance of the first transmission line 21 and the second transmission line 22 changes due to either one or both of the magnetic impedance effect on the surfaces of the first conductor 210 and the second conductor 220 and the effect of magnetization (magnetic wall movement) inside the first conductor 210 and the second conductor 220.

[0036] For example, an amorphous alloy with randomly arranged atoms may be an Fe-Co-Si-B alloy (Fe-rich), an Fe-Si-B-C alloy, an Fe-Si-B alloy, an Fe-Si-B-Nb-Cu alloy, or an Fe-P-B alloy, etc., which is an Fe-based amorphous alloy. Also, the amorphous alloy may be an Fe-Co-Si-B alloy (Co-rich), a Co-Fe-Cr-Si-B alloy, or a Co-Fe-Mn-Cr-Si-B alloy, etc., which is a Co-based amorphous alloy. Further, the amorphous alloy may be a Ni-based amorphous alloy.

[0037] For example, permalloy, which is an alloy mainly composed of Fe and Ni, may be 78-permalloy with a Ni content of 78.5% (JIS standard: permalloy A), 45-permalloy with a Ni content of 45% (40 - 50%) (JIS standard: permalloy B), or permalloy with Mo, Cu, or Cr added to 78-permalloy (JIS standard: permalloy C), etc.

[0038] The volume resistivity of permalloy is about 68 μΩcm. This is a volume resistivity more than 40 times that of copper with a volume resistivity of 1.68 μΩcm.

[0039] The first conductor 210 and the second conductor 220 may include, as soft magnetic materials other than amorphous alloys and permalloys, Fe-Si-Al alloys (e.g., Sendust), Fe-Co alloys (e.g., Permendur), Mn-Zn alloys or Ni-Zn alloys (e.g., soft ferrite), or Fe-Si alloys (e.g., silicon steel or electrical steel), etc.

[0040] When the magnetic field applied to the first transmission line 21 and the second transmission line 22 is a relatively large magnetic field of about 10 [Oe (Oersted)], the first conductor 210 and the second conductor 220 may include a single metal such as Fe, Ni, or Co as a magnetic material.

[0041] The first conductor 210 and the second conductor 220 may include a nanocrystalline soft magnetic material in which nanocrystalline grains are dispersed in an amorphous phase.

[0042] FIG. 2 is a diagram showing a schematic configuration of the measuring apparatus 10 of FIG. 1. The measuring apparatus 10 includes a signal generator 11, a signal detector 12, a control unit 13, a memory 14, and directional couplers (DC: Directional Coupler) 15-1 to 15-4. The measuring apparatus 10 also includes ports P1 to P4. The ports P1 to P4 are ports for inputting and outputting signals. The measuring apparatus 10 may be, for example, a measuring apparatus that functions as a vector network analyzer.

[0043] Although the illustration of the connections is omitted in FIG. 2, as shown in FIG. 1, the port P1 is connected to one end of the first transmission line 21. The port P2 is connected to the other end of the first transmission line 21. The port P3 is connected to one end of the second transmission line 22. The port P4 is connected to the other end of the second transmission line 22.

[0044] The signal generator 11 generates an incident wave input to the first transmission line 21 and an incident wave input to the second transmission line 22. Hereinafter, the incident wave input to the first transmission line 21 may be referred to as the "first incident wave", and the incident wave input to the second transmission line 22 may be referred to as the "second incident wave" for explanation.

[0045] The signal generator 11 outputs a sine wave signal by sweeping the frequency from 10 MHz to 50 GHz, for example, as the first incident wave and the second incident wave.

[0046] The signal generator 11 is connected to the directional couplers 15-1 to 15-4 and the signal detector 12.

[0047] The signal generator 11 outputs the generated first incident wave to the directional coupler 15-1 and inputs it to one end of the first transmission line 21 via the port P1. Alternatively, the signal generator 11 outputs the generated first incident wave to the directional coupler 15-2 and inputs it to the other end of the first transmission line 21 via the port P2.

[0048] The signal generator 11 outputs the generated second incident wave to the directional coupler 15-3 and inputs it to one end of the second transmission line 22 via port P3. Alternatively, the signal generator 11 outputs the generated second incident wave to the directional coupler 15-4 and inputs it to the other end of the second transmission line 22 via port P4.

[0049] The signal generator 11 outputs the generated first incident wave and second incident wave to the signal detector 12.

[0050] The signal detector 12 detects the first incident wave and second incident wave input from the signal generator 11. Also, the signal detector 12 detects the reflected waves input from the directional couplers 15-1 to 15-4.

[0051] The reflected waves detected by the signal detector 12 will be described. Assume that an external magnetic field is applied at a certain position of the magnetic sensor 20. Hereinafter, the position where the external magnetic field is applied may be referred to as the "magnetic field application position" for explanation.

[0052] When an external magnetic field is applied at a certain position of the magnetic sensor 20, the impedances of the first transmission line 21 and the second transmission line 22 change at the magnetic field application position. In this state, when the first incident wave is input to the first transmission line 21, a reflected wave is generated due to impedance mismatch at the magnetic field application position. Hereinafter, the reflected wave generated in the first transmission line 21 may be referred to as the "first reflected wave" for explanation. Also, in this state, when the second incident wave is input to the second transmission line 22, a reflected wave is generated due to impedance mismatch at the magnetic field application position. Hereinafter, the reflected wave generated in the second transmission line 22 may be referred to as the "second reflected wave" for explanation. Note that when there is no need to distinguish between the "first reflected wave" and the "second reflected wave", they may simply be referred to as "reflected waves" for explanation. Also, for the "first incident wave" and the "second incident wave", when there is no need to distinguish them, they may simply be referred to as "incident waves" for explanation.

[0053] For example, when the signal generator 11 outputs a first incident wave to the directional coupler 15-1, the first incident wave is input to one end of the first transmission line 21. The first reflected wave generated by the impedance mismatch of the first transmission line 21 at the magnetic field application position is input to the signal detector 12 via the port P1 and the directional coupler 15-1. In this way, the signal detector 12 detects the first reflected wave from one end of the first transmission line 21.

[0054] Also, for example, when the signal generator 11 outputs a first incident wave to the directional coupler 15-2, the first incident wave is input to the other end of the first transmission line 21. The first reflected wave generated by the impedance mismatch of the first transmission line 21 at the magnetic field application position is input to the signal detector 12 via the port P2 and the directional coupler 15-2. In this way, the signal detector 12 detects the first reflected wave from the other end of the first transmission line 21.

[0055] Also, for example, when the signal generator 11 outputs a second incident wave to the directional coupler 15-3, the second incident wave is input to one end of the second transmission line 22. The second reflected wave generated by the impedance mismatch of the second transmission line 22 at the magnetic field application position is input to the signal detector 12 via the port P3 and the directional coupler 15-3. In this way, the signal detector 12 detects the second reflected wave from one end of the second transmission line 22.

[0056] Also, for example, when the signal generator 11 outputs a second incident wave to the directional coupler 15-4, the second incident wave is input to the other end of the second transmission line 22. The second reflected wave generated by the impedance mismatch of the second transmission line 22 at the magnetic field application position is input to the signal detector 12 via the port P4 and the directional coupler 15-4. In this way, the signal detector 12 detects the second reflected wave from the other end of the second transmission line 22.

[0057] The signal detector 12 detects the vector ratio of the reflected wave to the incident wave for each frequency of the sine wave signal that the signal generator 11 sweeps and outputs. The vector ratio here refers to a vector defined by the reflectivity and the phase difference of the reflected wave with respect to the incident wave. Here, the reflectivity of the reflected wave with respect to the incident wave is the amplitude of the reflected wave divided by the amplitude of the incident wave. Also, the phase difference of the reflected wave with respect to the incident wave is the phase of the reflected wave minus the phase of the incident wave.

[0058] The signal detector 12 outputs, as frequency domain data, the vector ratio of the first reflected wave to the first incident wave for each frequency of the first incident wave to the control unit 13. Also, the signal detector 12 outputs, as frequency domain data, the vector ratio of the second reflected wave to the second incident wave for each frequency of the second incident wave to the control unit 13.

[0059] The control unit 13 controls each component of the measuring device 10. The control unit 13 may be configured as a processor such as a CPU (Central Processing Unit), for example. Details of the functions of the control unit 13 will be described later.

[0060] The memory 14 is connected to the control unit 13. The memory 14 has an arbitrary storage device such as an HDD (Hard Disc Drive), an SSD (Solid State Drive), an EEPROM (Electrically Erasable Programmable Read-Only Memory), a ROM (Read-Only Memory), and a RAM (Random Access Memory), for example. The memory 14 may function as, for example, a main memory device, an auxiliary memory device, or a cache memory. The memory 14 is not limited to being built into the measuring device 10 and may be an external storage device connected by a digital input / output port such as a USB (Universal Serial Bus).

[0061] The control unit 13 performs an inverse Fourier transform on the frequency-domain data of the vector ratio of the first reflected wave with respect to the first incident wave acquired from the signal detector 12 to generate the time-domain data of the first reflected wave. Further, the control unit 13 performs an inverse Fourier transform on the frequency-domain data of the vector ratio of the second reflected wave with respect to the second incident wave acquired from the signal detector 12 to generate the time-domain data of the second reflected wave.

[0062] The control unit 13 acquires the first incident wave output from the signal generator 11 via the signal detector 12 and performs an inverse Fourier transform to generate the time-domain data of the first incident wave. The control unit 13 can calculate the magnetic field application position in the first transmission line 21 based on the time-domain data of the first incident wave and the time-domain data of the first reflected wave. The control unit 13 can calculate the magnetic field application position in the first transmission line 21 based on the difference between the time when the time-domain data of the first incident wave is detected and the time when the time-domain data of the first reflected wave is detected.

[0063] Further, the control unit 13 can calculate the magnetic field strength at the magnetic field application position of the first transmission line 21 based on the time-domain data of the first incident wave and the time-domain data of the first reflected wave. When the magnetic field strength at the magnetic field application position of the first transmission line 21 is large, the impedance mismatch at the magnetic field application position becomes large. Therefore, when the magnetic field strength at the magnetic field application position of the first transmission line 21 increases, the ratio of the amplitude of the time-domain data of the first reflected wave to the amplitude of the time-domain data of the first incident wave increases. Accordingly, the control unit 13 can calculate the magnetic field strength at the magnetic field application position based on the ratio of the amplitude of the time-domain data of the first reflected wave to the amplitude of the time-domain data of the first incident wave. Here, the magnetic field strength at the magnetic field application position of the first transmission line 21 calculated by the control unit 13 is the magnetic field strength in the direction along the first transmission line 21. Thus, the control unit 13 can simultaneously calculate the magnetic field application position in the first transmission line 21 and the magnetic field strength at the magnetic field application position of the first transmission line 21 by, for example, the method described in Patent Document 1.

[0064] The control unit 13 acquires the second incident wave output from the signal generator 11 via the signal detector 12, performs an inverse Fourier transform, and generates time-domain data of the second incident wave. The control unit 13 can calculate the magnetic field application position in the second transmission line 22 based on the time-domain data of the second incident wave and the time-domain data of the second reflected wave. The control unit 13 can calculate the magnetic field application position in the second transmission line 22 based on the difference between the time when the time-domain data of the second incident wave is detected and the time when the time-domain data of the second reflected wave is detected.

[0065] Also, the control unit 13 can calculate the intensity of the magnetic field at the magnetic field application position of the second transmission line 22 based on the time-domain data of the second incident wave and the time-domain data of the second reflected wave. When the intensity of the magnetic field at the magnetic field application position of the second transmission line 22 is large, the impedance mismatch at the magnetic field application position becomes large. Therefore, when the intensity of the magnetic field at the magnetic field application position of the second transmission line 22 increases, the ratio of the amplitude of the time-domain data of the second reflected wave to the amplitude of the time-domain data of the second incident wave increases. Accordingly, the control unit 13 can calculate the intensity of the magnetic field at the magnetic field application position based on the ratio of the amplitude of the time-domain data of the second reflected wave to the amplitude of the time-domain data of the second incident wave. Here, the intensity of the magnetic field at the magnetic field application position of the second transmission line 22 calculated by the control unit 13 is the intensity of the magnetic field in the direction along the second transmission line 22. Thus, the control unit 13 can simultaneously calculate the magnetic field application position in the second transmission line 22 and the intensity of the magnetic field at the magnetic field application position of the second transmission line 22, for example, by the method described in Patent Document 1.

[0066] The control unit 13 calculates a two-axis magnetic field based on the magnetic field in the direction along the first transmission line 21 and the magnetic field in the direction along the second transmission line 22 calculated as described above. The calculation of the two-axis magnetic field by the control unit 13 will be described with reference to FIGS. 3 to 6.

[0067] FIG. 3 is a diagram showing a schematic configuration of the magnetic sensor 20. As shown in FIG. 3, it is assumed that the longitudinal direction of the substrate 23 is the Y-axis direction and the lateral direction of the substrate 23 is the X-axis direction. A case where a uniform magnetic field H is externally applied in the region R shown on the substrate 23 in FIG. 3 will be described as an example.

[0068] FIG. 4 is an enlarged view of the region R shown in FIG. 3. As shown in FIG. 4, it is assumed that a uniform magnetic field H is externally applied to the region R. The magnetic field H can be vectorially decomposed into a two-axis magnetic field consisting of a magnetic field H x in the X-axis direction and a magnetic field H y in the Y-axis direction.

[0069] FIG. 4 shows a case where the first transmission line 21 is in the direction at an angle θ from the positive direction of the X-axis and the second transmission line 22 is in the direction at an angle θ from the negative direction of the X-axis.

[0070] FIG. 5 shows a state in which the magnetic field H x is vectorially decomposed in the direction along the first transmission line 21 and a state in which the magnetic field H x is vectorially decomposed in the direction along the second transmission line 22.

[0071] As shown in FIG. 5, the magnitude of the magnetic field component obtained by vectorially decomposing the magnetic field H x in the direction along the first transmission line 21 is H x cosθ. Also, the magnitude of the magnetic field component obtained by vectorially decomposing the magnetic field H x in the direction along the second transmission line 22 is H x cosθ.

[0072] FIG. 6 shows a state in which the magnetic field H y is vectorially decomposed in the direction along the first transmission line 21 and a state in which the magnetic field H y is vectorially decomposed in the direction along the second transmission line 22.

[0073] As shown in FIG. 6, the magnitude of the magnetic field component obtained by vectorially decomposing the magnetic field H y in the direction along the first transmission line 21 is H y sinθ. Also, the magnetic field Hy The magnitude of the magnetic field of the component vector-decomposed in the direction along the second transmission line 22 is H y sinθ.

[0074] Here, assuming the magnetic field in the direction along the first transmission line 21 is the magnetic field H1, by synthesizing the magnetic field vectors shown in FIGS. 5 and 6, the magnetic field H1 is expressed as in the following formula (1).

Equation

[0075] Also, assuming the magnetic field in the direction along the second transmission line 22 is the magnetic field H2, by synthesizing the magnetic field vectors shown in FIGS. 5 and 6, the magnetic field H2 is expressed as in the following formula (2). In formula (2), the negative sign in front of H x cosθ is because the direction is opposite to that of H y sinθ in the second term on the right side.

Equation

[0076] Hereafter, there may be cases where the magnetic field H1 in the direction along the first transmission line 21 is described as the "first magnetic field". Also, there may be cases where the magnetic field H2 in the direction along the second transmission line 22 is described as the "second magnetic field".

[0077] Based on formulas (1) and (2), the magnetic field H x in the X-axis direction and the magnetic field H y in the Y-axis direction can be calculated as follows, respectively.

Equation

Equation

[0078] The control unit 13 calculates a first magnetic field H1 in the direction along the first transmission line 21 based on the first incident wave and the first reflected wave, and calculates a second magnetic field H2 in the direction along the second transmission line 22 based on the second incident wave and the second reflected wave. The control unit 13 performs operations as shown in equations (3) and (4) based on the first magnetic field H1 and the second magnetic field H2, thereby calculating the magnetic field H x in the X-axis direction and the magnetic field H y in the Y-axis direction, i.e., calculating the magnetic field in two-axis directions.

[0079] Thus, the magnetic detection device 1 can detect the first magnetic field H1 in the direction along the first transmission line 21 and the second magnetic field H2 in the direction along the second transmission line 22 by the first transmission line 21 and the second transmission line 22 arranged non-parallel to each other. Then, the magnetic detection device 1 calculates the magnetic field H x in the X-axis direction and the magnetic field H y in the Y-axis direction, i.e., calculating the magnetic field in two-axis directions.

[0080] (Offset data) When calculating the first magnetic field and the second magnetic field based on the first reflected wave and the second reflected wave, the measuring device 10 may use, as the data of the first reflected wave and the second reflected wave used when calculating the first magnetic field and the second magnetic field, the differential data obtained by subtracting the offset data. The measuring device 10 may store, as offset data, the data of the first reflected wave and the second reflected wave detected when no magnetic field is applied to the first transmission line 21 and the second transmission line 22 in the memory 14. In this way, the measuring device 10 can reduce the influence other than the external magnetic field and calculate the first magnetic field and the second magnetic field by using, as the data of the first reflected wave and the second reflected wave for calculating the first magnetic field and the second magnetic field, the differential data obtained by subtracting the offset data from the detected data of the first reflected wave and the second reflected wave. For example, the measuring device 10 can reduce the influence of reflected waves caused by mechanical tolerances of the components of the first transmission line 21 and the second transmission line 22, distortion caused by bending of the first transmission line 21 and the second transmission line 22, environmental magnetic fields applied from the initial state (for example, magnetic fields generated from geomagnetism or electronic devices), etc.

[0081] (Application of Bias Magnetic Field) The magnetic detection device 1 may include a coil around the first transmission line 21 and the second transmission line 22. The magnetic detection device 1 can apply a bias magnetic field in the direction along the first transmission line 21 and the second transmission line by passing a bias current through the coil installed around the first transmission line 21 and the second transmission line 22.

[0082] By applying the bias magnetic field as described above, the measuring device 10 can calculate the first magnetic field and the second magnetic field at an operating point showing high linearity, small hysteresis, and high sensitivity. Thereby, the measuring device 10 can calculate the magnetic field in the two-axis direction with high accuracy.

[0083] According to the magnetic detection device 1 according to the above-described embodiment, it is possible to detect a magnetic field in two axial directions. More specifically, the magnetic sensor 20 includes a first transmission line 21 and a second transmission line 22, and the first transmission line 21 and the second transmission line 22 are arranged non-parallel to each other. The control unit 13 of the measuring device 1 calculates a first magnetic field in the direction along the first transmission line 21 at the magnetic field application position based on the first incident wave and the first reflected wave, and calculates a second magnetic field in the direction along the second transmission line 22 at the magnetic field application position based on the second incident wave and the second reflected wave, and calculates a magnetic field in two axial directions based on the first magnetic field and the second magnetic field. In this way, since the magnetic sensor 20 includes the first transmission line 21 and the second transmission line 22 arranged non-parallel to each other, the magnetic detection device 1 can calculate a magnetic field in two axial directions based on the first magnetic field detected by the first transmission line 21 and the second magnetic field detected by the second transmission line 22.

[0084] Further, according to the magnetic detection device 1 according to the embodiment, since the position of the magnetic field applied to the magnetic sensor 20 and the intensity of the magnetic field applied to the magnetic sensor 20 can be detected simultaneously, it is possible to detect a non-uniform external magnetic field generated from the measurement target. Therefore, the magnetic detection device 1 can measure an external magnetic field generated by the magnetization distribution of the magnetic material that is the measurement target, and an external magnetic field generated by the magnetic field distribution due to defects on the surface of the metal that is the measurement target. Further, the magnetic detection device 1 can be applied to various measurement devices such as geomagnetic detection, eddy current flaw detection, magnetic microscopy, current sensors, and magnetoencephalographs.

[0085] (First Modified Example) FIG. 7 is a diagram showing a magnetic sensor 20a according to the first modified example. In the magnetic sensor 20a shown in FIG. 7, a first transmission line 21a is formed on the surface of a substrate 23. Also, a second transmission line 22a is formed on the back surface of the substrate 23.

[0086] In FIG. 7, in order to make the shape of the first transmission line 21a easier to see, a diagram showing only the first transmission line 21a and omitting the illustration of the second transmission line 22a is shown on the left side.

[0087] In order to make the shape of the second transmission line 22a easier to see, a diagram showing only the second transmission line 22a and omitting the illustration of the first transmission line 21a is shown on the right side.

[0088] Both the diagram showing only the first transmission line 21a shown on the left side and the diagram showing only the second transmission line 22a shown on the right side are views seen from the positive Z-axis side. Since the second transmission line 22a is on the back surface of the substrate 23, it is shown by a dashed line.

[0089] The magnetic sensor 20a according to the first modification example has a shape in which the substrate 23 is extended in the longitudinal direction (Y-axis direction) in order to expand the range in which the magnetic sensor 20a can detect a magnetic field.

[0090] For example, in the magnetic sensor 20 as shown in FIG. 3, when the substrate 23 is extended in the Y-axis direction while maintaining the angle θ shown in FIG. 4, the length of the substrate 23 in the X-axis direction also becomes longer. Then, the X-axis direction of the magnetic sensor 20 also extends, and the shape of the magnetic sensor 20 becomes larger.

[0091] In order to prevent the shape of the magnetic sensor 20 from becoming larger, when the substrate 23 is extended in the Y-axis direction with the angle θ shown in FIG. 4 made close to 90 degrees, the sensitivity of the magnetic field in the X-axis direction decreases.

[0092] The magnetic sensor 20a according to the first modification example is configured such that the substrate 23 can be extended in the Y-axis direction without increasing the length of the substrate 23 in the X-axis direction and without decreasing the sensitivity of the magnetic field in the X-axis direction.

[0093] As shown in the left diagram of FIG. 7, the first transmission line 21a includes a plurality of first conductors 210. The first conductor 210 is a linear conductor containing a magnetic material. Adjacent first conductors 210 are connected by a non-magnetic material conductor 211. The non-magnetic material conductor 211 may be, for example, a copper wire. The non-magnetic material conductor 211 is arranged along the short side direction (X-axis direction) of the substrate 23. The first transmission line 21a has a sawtooth shape as a whole.

[0094] In addition, in FIG. 7, the first transmission line 21a includes five first conductors 210, but this is just an example. The first transmission line 21a may include two to four first conductors 210, or may include six or more first conductors 210.

[0095] As shown in the figure on the right side of FIG. 7, the second transmission line 22a includes a plurality of second conductors 220. The second conductor 220 is a linear conductor containing a magnetic material. Adjacent second conductors 220 are connected by a non-magnetic material conductor 221. The non-magnetic material conductor 221 may be, for example, a copper wire. The non-magnetic material conductor 221 is arranged along the short side direction (X-axis direction) of the substrate 23. The second transmission line 22a has a sawtooth shape as a whole.

[0096] In addition, in FIG. 7, the second transmission line 22a includes five second conductors 220, but this is just an example. The second transmission line 22a may include two to four second conductors 220, or may include six or more second conductors 220.

[0097] As shown in FIG. 7, the plurality of first conductors 210 and the plurality of second conductors 220 are arranged non-parallelly. Therefore, in the magnetic detection device 1 shown in FIG. 1, even if the magnetic sensor 20a according to the first modification is used instead of the magnetic sensor 20, the magnetic detection device 1 can calculate the magnetic field in the two-axis direction.

[0098] Also, since the first transmission line 21a and the second transmission line 22a have a sawtooth shape, the magnetic sensor 20a according to the first modification can extend the substrate 23 in the Y-axis direction without increasing the length of the substrate 23 in the X-axis direction and without reducing the sensitivity of the magnetic field in the X-axis direction.

[0099] Therefore, the magnetic sensor 20a according to the first modification can expand the range in which the magnetic sensor 20a can detect the magnetic field in the Y-axis direction without increasing the length of the substrate 23 in the X-axis direction and without reducing the sensitivity of the magnetic field in the X-axis direction.

[0100] Note that, in FIG. 7, a configuration is shown in which the first transmission line 21a is formed on the surface of the substrate 23 and the second transmission line 22a is formed on the back surface of the substrate 23. However, the present invention is not limited to this configuration. For example, when the substrate 23 is a multilayer substrate, the first transmission line 21a and the second transmission line 22a may be formed in different layers of the substrate 23.

[0101] (Second Modification Example) FIG. 8 is a diagram showing the magnetic sensor 20b according to the second modification example. Regarding the magnetic sensor 20b according to the second modification example, differences from the magnetic sensor 20a according to the first modification example shown in FIG. 7 will be mainly described, and descriptions of parts common or similar to the magnetic sensor 20a will be omitted.

[0102] As shown in the left diagram of FIG. 8, the first transmission line 21b includes a plurality of first conductors 210. Adjacent first conductors 210 are connected by a conductor 211 made of a non-magnetic material. The conductor 211 made of a non-magnetic material is arranged in a direction oblique to the short side direction (X-axis direction) of the substrate 23, different from the conductor 211 shown on the left side of FIG. 7. The first transmission line 21b has a sawtooth shape as a whole.

[0103] As shown in the right diagram of FIG. 8, the second transmission line 22b includes a plurality of second conductors 220. Adjacent second conductors 220 are connected by a conductor 221 made of a non-magnetic material. The conductor 221 made of a non-magnetic material is arranged in a direction oblique to the short side direction (X-axis direction) of the substrate 23, different from the conductor 221 shown on the right side of FIG. 7. The second transmission line 22b has a sawtooth shape as a whole.

[0104] Referring to the left diagram of FIG. 8, two adjacent first conductors 210 among the plurality of first conductors 210 have an overlapping region S in the longitudinal direction (Y-axis direction) of the magnetic sensor 20b.

[0105] By having such an overlapping region S, the first transmission line 21b can detect a magnetic field at all positions in the Y-axis direction. Similarly, the second transmission line 22b can also detect a magnetic field at all positions in the Y-axis direction by having the overlapping region S.

[0106] For example, referring to the left figure in Fig. 7, in the magnetic sensor 20a according to the first modification example, the first transmission line 21a includes a plurality of first conductors 210, and adjacent first conductors 210 are connected by a conductor 211 made of a non-magnetic material. At this time, the first conductor 210 and the conductor 211 are connected via pads, but the pad portions are regions where the first conductors 210 do not exist in the Y-axis direction. That is, there is a possibility that this region may have low sensitivity to an external magnetic field.

[0107] The magnetic sensor 20b according to the second modification example can prevent the existence of a region that may have low sensitivity to such an external magnetic field.

[0108] It is obvious to those skilled in the art that the present disclosure can be realized in other specific forms other than the above-described embodiments without departing from its spirit or its essential features. Therefore, the foregoing description is illustrative and not restrictive. The scope of the disclosure is defined by the appended claims rather than by the foregoing description. Some modifications within the equivalent scope of any change are included therein.

[0109] For example, the arrangement and number of each of the above-described components are not limited to the contents shown in the above description and drawings. The arrangement and number of each component may be arbitrarily configured as long as its function can be realized.

[0110] For example, in the above-described embodiment, the case where each of the first transmission line 21 and the second transmission line 22 is one has been described as an example. However, the number of the first transmission line 21 and the second transmission line 22 is not limited to this. The magnetic sensor 20 may include a plurality of first transmission lines 21 that are arranged parallel to each other and connected in parallel. Further, the magnetic sensor 20 may include a plurality of second transmission lines 22 that are arranged parallel to each other and connected in parallel. In this case, the plurality of first transmission lines 21 and the plurality of second transmission lines 22 are arranged non-parallel to each other. When permalloy is used as the linear first conductor 210 and the linear second conductor 220, the volume resistivity of permalloy is about 68 μΩcm, which is more than 40 times larger than the volume resistivity of copper of 1.68 μΩcm. Further, since the maximum permeability of permalloy is very high, there is a problem that the resistance loss due to the skin effect at high-frequency input becomes large and the attenuation amount becomes large. If the magnetic sensor 20 is configured to include a plurality of first transmission lines 21 and a plurality of second transmission lines 22, the resistance loss caused by the first conductor 210 and the second conductor 220 can be reduced.

[0111] For example, in the above-described embodiment, the case where the signal generator 11 outputs a sine wave signal by sweeping the frequency has been described as an example. However, the waveform generated by the signal generator 11 is not limited to this. For example, the signal generator 11 may generate a pulse and input the generated pulse to the first transmission line 21 and the second transmission line 22.

[0112] Some embodiments of the present disclosure are illustrated below. However, it should be noted that the embodiments of the present disclosure are not limited to these. [Appendix 1] A magnetic detection device including a magnetic sensor and a measuring device, wherein the magnetic sensor, a first transmission line including a linear first conductor containing a magnetic material, a second transmission line including a linear second conductor containing a magnetic material, and the first transmission line and the second transmission line are arranged non-parallel to each other, The measurement device A signal generator that generates a first incident wave input to the first transmission line and a second incident wave input to the second transmission line, A signal detector that detects a first reflected wave generated by impedance mismatch of the first transmission line at the magnetic field application position to the magnetic sensor and a second reflected wave generated by impedance mismatch of the second transmission line at the magnetic field application position, A control unit, and includes, The control unit calculates a first magnetic field in the direction along the first transmission line at the magnetic field application position based on the first incident wave and the first reflected wave, calculates a second magnetic field in the direction along the second transmission line at the magnetic field application position based on the second incident wave and the second reflected wave, A magnetic detection device that calculates a magnetic field in a two-axis direction based on the first magnetic field and the second magnetic field. [Appendix 2] In the magnetic detection device according to Appendix 1, The magnetic sensor A plurality of the first transmission lines arranged in parallel and connected in parallel, A plurality of the second transmission lines arranged in parallel and connected in parallel, and includes, A magnetic detection device in which the plurality of first transmission lines and the plurality of second transmission lines are arranged non-parallel to each other. [Appendix 3] In the magnetic detection device according to Appendix 1 or 2, The first transmission line and the second transmission line are any one of a coaxial cable, a parallel two-wire line, a strip line, a microstrip line, a coplanar line, and a waveguide. A magnetic detection device. [Appendix 4] In the magnetic detection device according to any one of Appendices 1 to 3, The first transmission line includes a plurality of the first conductors, The plurality of first conductors are connected by at least one non-magnetic material conductor, The first transmission line has a sawtooth shape, The second transmission line includes a plurality of the second conductors, The plurality of the second conductors are connected by at least one non-magnetic material conductor, The second transmission line has a sawtooth shape, A magnetic detection device in which the plurality of the first conductors and the plurality of the second conductors are arranged non-parallelly. [Appendix 5] In the magnetic detection device according to Appendix 4, Two adjacent first conductors among the plurality of the first conductors have an overlapping region in the longitudinal direction of the magnetic sensor, A magnetic detection device in which two adjacent second conductors among the plurality of the second conductors have an overlapping region in the longitudinal direction of the magnetic sensor. [Appendix 6] In the magnetic detection device according to any one of Appendices 1 to 5, The magnetic detection device further includes a coil for applying a bias magnetic field to the first transmission line and the second transmission line. [Appendix 7] A first transmission line including a linear first conductor containing a magnetic material, A second transmission line including a linear second conductor containing a magnetic material, Comprising, A magnetic sensor in which the first transmission line and the second transmission line are arranged non-parallelly. [Appendix 8] A magnetic detection method in a magnetic detection device including a magnetic sensor and a measuring device, The magnetic sensor is, A first transmission line including a linear first conductor containing a magnetic material, A second transmission line including a linear second conductor containing a magnetic material, Comprising, The first transmission line and the second transmission line are arranged non-parallelly, The magnetic detection method is, The measuring device, Generating a first incident wave input to the first transmission line and a second incident wave input to the second transmission line; Detecting a first reflected wave generated by impedance mismatch of the first transmission line at the magnetic field application position to the magnetic sensor and a second reflected wave generated by impedance mismatch of the second transmission line at the magnetic field application position; Calculating a first magnetic field in the direction along the first transmission line at the magnetic field application position based on the first incident wave and the first reflected wave; Calculating a second magnetic field in the direction along the second transmission line at the magnetic field application position based on the second incident wave and the second reflected wave; Calculating a magnetic field in a two-axis direction based on the first magnetic field and the second magnetic field. A magnetic detection method comprising:

Explanation of symbols

[0113] 1 Magnetic detection device 10 Measuring device 11 Signal generator 12 Signal detector 13 Control unit 14 Memory 15 Directional coupler (DC) 20, 20a, 20b Magnetic sensors 21, 21a, 21b First transmission lines 22, 22a, 22b Second transmission lines 23 Substrate 210 First conductor 211 Conductor (of non-magnetic material) 220 Second conductor 221 Conductor (of non-magnetic material)

Claims

1. A magnetic detection device comprising a magnetic sensor and a measuring device, wherein the magnetic sensor, comprises a first transmission line including a linear first conductor containing a magnetic material, and a second transmission line including a linear second conductor containing a magnetic material, and the first transmission line and the second transmission line are arranged non-parallel to each other, and the measuring device, comprises a signal generator for generating a first incident wave input to the first transmission line and a second incident wave input to the second transmission line, a signal detector for detecting a first reflected wave generated by impedance mismatch of the first transmission line at the magnetic field application position to the magnetic sensor and a second reflected wave generated by impedance mismatch of the second transmission line at the magnetic field application position, and a control unit, and the control unit, calculates a first magnetic field in the direction along the first transmission line at the magnetic field application position based on the first incident wave and the first reflected wave, calculates a second magnetic field in the direction along the second transmission line at the magnetic field application position based on the second incident wave and the second reflected wave, and calculates a magnetic field in a two-axis direction based on the first magnetic field and the second magnetic field, a magnetic detection device.

2. In the magnetic detection device according to claim 1, the magnetic sensor, comprises a plurality of the first transmission lines arranged in parallel and connected in parallel to each other, and a plurality of the second transmission lines arranged in parallel and connected in parallel to each other, and the plurality of the first transmission lines and the plurality of the second transmission lines are arranged non-parallel to each other, a magnetic detection device.

3. In the magnetic detection device according to claim 1, the first transmission line and the second transmission line are any one of a coaxial cable, a parallel two-wire line, a strip line, a microstrip line, a coplanar line, and a waveguide, a magnetic detection device.

4. In the magnetic detection device according to claim 1, the first transmission line includes a plurality of the first conductors, the plurality of the first conductors are connected by at least one non-magnetic conductor, the first transmission line has a sawtooth shape, the second transmission line includes a plurality of the second conductors, the plurality of the second conductors are connected by at least one non-magnetic conductor, the second transmission line has a sawtooth shape, and the plurality of the first conductors and the plurality of the second conductors are arranged non-parallel to each other, a magnetic detection device.

5. In the magnetic detection device according to claim 4, Two adjacent first conductors among the plurality of first conductors have overlapping regions in the longitudinal direction of the magnetic sensor. A magnetic detection device, wherein two adjacent second conductors among the plurality of second conductors have overlapping regions in the longitudinal direction of the magnetic sensor. **Claim 6** The magnetic detection device according to claim 1, further comprising a coil for applying a bias magnetic field to the first transmission line and the second transmission line. **Claim 7** A first transmission line including a linear first conductor containing a magnetic material, a second transmission line including a linear second conductor containing a magnetic material, comprising: a magnetic sensor, wherein the first transmission line and the second transmission line are arranged non-parallel to each other. **Claim 8** A magnetic detection method in a magnetic detection device including a magnetic sensor and a measuring device, wherein the magnetic sensor comprises a first transmission line including a linear first conductor containing a magnetic material, a second transmission line including a linear second conductor containing a magnetic material, and the first transmission line and the second transmission line are arranged non-parallel to each other, and the magnetic detection method comprises the steps of: the measuring device generating a first incident wave input to the first transmission line and a second incident wave input to the second transmission line; detecting a first reflected wave generated by impedance mismatch of the first transmission line at the magnetic field application position to the magnetic sensor and a second reflected wave generated by impedance mismatch of the second transmission line at the magnetic field application position; calculating a first magnetic field in the direction along the first transmission line at the magnetic field application position based on the first incident wave and the first reflected wave; calculating a second magnetic field in the direction along the second transmission line at the magnetic field application position based on the second incident wave and the second reflected wave; and calculating a magnetic field in a two-axis direction based on the first magnetic field and the second magnetic field.

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