Magnetic field generator and magnetic sensor having the same

Abstract

A magnetic field generator includes an upper layer coil (20) composed of a first conductive material and forming a loop circuit having a coil portion (21), a lower layer coil (30) composed of a second conductive material and forming a loop circuit having a coil portion (31) disposed in opposition to the coil portion of the upper layer coil at a predetermined distance, and a substrate (10) supporting the upper layer coil and the lower layer coil and having a dielectric material between the upper layer coil and the lower layer coil. High frequency currents of opposite phases pass through the upper layer coil and the lower layer coil, respectively, and each loop length of the coil portion in the upper layer coil and the coil portion in the lower layer coil matches one wavelength of the high frequency currents.

Description

Technical Field

[0001] This disclosure generally relates to a magnetic field generator and a magnetic sensor having the magnetic field generator. Background Technology

[0002] For comparison, Patent Document 1 (Japanese Unexamined Patent Publication No. 2008-2933) discloses an annular resonator corresponding to a magnetic field generator that produces a high-frequency magnetic field in the axial direction of a coil. In the annular resonator, an electric field with the same path is generated along the entire circumference of the annular electrode (in other words, a cylindrical electrode). That is, a magnetic field is generated at one end of the cylinder in the axial direction along a path extending from the inside to the outside of the cylinder formed by the electrode, and the magnetic field is further guided along the outer circumferential surface of the cylinder to the other end of the cylinder, and the magnetic field returns to the inside of the cylinder. Therefore, a high-frequency magnetic field is generated in the axial direction of the coil, which passes through the interior of the cylindrical coil formed by the electrode. Summary of the Invention

[0003] In one embodiment of the invention, an example is a magnetic sensor that uses optically detected magnetic resonance (ODMR) of a diamond element comprising an NV center (NVC: nitrogen-vacancy center) to detect a magnetic field. This magnetic sensor comprises a magnetic field generator, a light source, and a light receiving unit. The magnetic field generator consists of a diamond element and a coil. The coil applies a high-frequency magnetic field in the microwave band to induce electron spin resonance (ESR) in the diamond element. The light source illuminates the diamond element with green light for spin initialization and for exciting unpaired electrons in the NVC. The light receiving unit receives wavelength-converted red fluorescence in the diamond element. In this magnetic sensor, the strength of the external magnetic field is measured by reading the energy difference of Zeeman separation in the ground state of the NVC with unpaired electrons using ODMR. That is, the strength of the external magnetic field measured by this magnetic sensor is the strength at the location of the diamond element, and furthermore, the magnetic sensor is characterized in that its sensitivity to the external magnetic field (the measured magnetic field) is limited only in the direction orthogonal to the direction of the high-frequency magnetic field applied to the diamond element by the magnetic field generator.

[0004] When the magnetic field generator is constructed from a cylindrical annular resonator as in Patent Document 1, assuming the axial direction of the coil is the Z direction and the plane perpendicular to the axial direction is the XY plane, a high-frequency magnetic field is generated in the Z-axis direction, and the sensitivity axis of the generated external magnetic field is included in the XY plane orthogonal to the Z-axis direction.

[0005] If a small external magnetic field needs to be detected, the magnetic field source and the magnetic sensor must be brought closer together. If the sensor is a cylindrical annular resonator, the target to be detected must be brought closer to the inside of the cylinder. However, since there are annular coils, resonators, and a substrate on which these annular coils and resonators are mounted in the XY plane, there may be certain limitations on how close the resonator (i.e., the cylinder) and the target to be detected can be.

[0006] On the other hand, if the external magnetic field source is placed directly above or below the cylindrical magnetic field generator, i.e., at one of two adjacent locations in the axial direction, the distance between them becomes shorter. However, because the annular resonator has no sensitivity in the axial direction, the external magnetic field cannot be measured. To generate sensitivity in the axial direction, a high-frequency magnetic field must be generated in the XY plane.

[0007] The purpose of this disclosure is to provide a magnetic field generator that can generate a high-frequency magnetic field in the XY plane when the axis of the coil is set as the Z-axis and the plane perpendicular to the Z-axis is set as the XY plane, and also to provide a magnetic sensor having the above-mentioned magnetic field generator.

[0008] In one aspect of such a magnetic field generator for the aforementioned purpose, the magnetic field generator includes:

[0009] The upper coil is made of a first conductive material and provides a ring circuit with coil portions;

[0010] The lower coil is made of a second conductive material and provides a ring circuit with coil portions arranged to face the coil portions of the upper coil at a predetermined distance.

[0011] A substrate supporting the upper coil and the lower coil, and using a dielectric material as filler between the upper coil and the lower coil; and

[0012] A grounding layer having a ground potential is arranged to sandwich the upper coil and the lower coil between one surface and the other surface of the substrate.

[0013] In addition, the high-frequency currents in opposite phases pass through the upper and lower coils respectively, and the length of each loop in the upper coil and the length of each loop in the lower coil are adjusted to one wavelength of the high-frequency current.

[0014] With this configuration, the upper portion of the substrate with the upper coil and the lower portion of the substrate with the lower coil each have the same magnetic field direction at the lower coil face of the upper portion of the upper portion. In this way, a high-frequency magnetic field with the XY plane as the magnetic field direction can be generated at the position between the upper and lower coils.

[0015] Note that the reference numerals in parentheses attached to each component, etc., indicate examples of the correspondence between (i) the component, etc. and (ii) the specific component, etc. in the following embodiments. Attached Figure Description

[0016] Figure 1 This is a general structural diagram of a magnetic sensor equipped with a magnetic field generator according to the first embodiment;

[0017] Figure 2 It shows along Figure 1 A diagram showing the cross-section taken from line II-II;

[0018] Figure 3 It shows from Figure 1 The image of the magnetic field generator extracted from it;

[0019] Figure 4A This is a diagram showing the relationship between the physical length and electrical length of the wiring in a ring circuit when the dielectric constant of the substrate is the same.

[0020] Figure 4B This diagram illustrates the relationship between the dielectric constant of the substrate and the electrical length when the physical length of the wiring in a ring circuit is the same.

[0021] Figure 5A This is a perspective view showing the magnetic field generated in the lower coil;

[0022] Figure 5B It is a perspective view showing the magnetic fields generated in the lower and upper coils and the resulting high-frequency magnetic fields;

[0023] Figure 6 It is a cross-sectional view showing the magnetic field generated in the lower and upper coils and the resulting high-frequency magnetic field;

[0024] Figure 7 It is a waveform diagram of high-frequency current;

[0025] Figure 8 This is a cross-sectional view showing the high-frequency magnetic field generated by a winding coil wound multiple times as a comparative example;

[0026] Figure 9A It is a diagram that uses arrows to simulate the direction of the current flowing through the upper and lower coils;

[0027] Figure 9B yes Figure 9A A magnified view of the IXB region;

[0028] Figure 9C yes Figure 9A A magnified view of the IXC region;

[0029] Figure 10 This is a diagram showing the simulation results of the high-frequency magnetic field generated by the magnetic field generator;

[0030] Figure 11 This is a diagram showing a magnetic field generator installed in a magnetic sensor according to the second embodiment;

[0031] Figure 12 This illustrates the magnetic fields generated in the lower and upper coils, and the resulting high-frequency magnetic fields. Figure 11 Cross-sectional view of section XII-XII;

[0032] Figure 13 This is a diagram showing a magnetic field generator installed in a magnetic sensor according to a third embodiment;

[0033] Figure 14 It is along Figure 13 A cross-sectional view taken from the XIV-XIV line;

[0034] Figure 15 This is a diagram showing a magnetic field generator installed in a magnetic sensor according to the fourth embodiment;

[0035] Figure 16 It is along Figure 15 A cross-sectional view taken from the XVI-XVI line;

[0036] Figure 17 This is a diagram showing a magnetic field generator installed in a magnetic sensor according to the fifth embodiment;

[0037] Figure 18 It is a diagram showing the various positions from point G to K between the first and second lead portions in the upper coil;

[0038] Figure 19A This illustrates the standing wave of high-frequency current and Figure 18 A graph showing the relationship between points G and K in the graph;

[0039] Figure 19B This illustrates the standing wave of high-frequency current and Figure 18 A graph showing the relationship between points G and K in the graph;

[0040] Figure 20A This is a diagram showing the state in the sixth embodiment where the magnetic field direction is clockwise;

[0041] Figure 20B This is a diagram showing the state in the sixth embodiment where the magnetic field direction is counterclockwise;

[0042] Figure 21 This is a general structural diagram of a magnetic sensor equipped with a magnetic field generator according to the seventh embodiment;

[0043] Figure 22 It is along Figure 21 A cross-sectional view taken from the XXII-XXII line;

[0044] Figure 23 It shows from Figure 21 The image of the magnetic field generator extracted from it;

[0045] Figure 24 It is a diagram that uses arrows to simulate the direction of current flowing through the upper and lower coils; and

[0046] Figure 25 This is a graph showing the simulation results of a high-frequency magnetic field generated by a magnetic field generator. Detailed Implementation

[0047] In the following description, embodiments of the present disclosure will be referenced to the accompanying drawings. In the following embodiments, the same or equivalent parts are indicated by the same reference numerals.

[0048] (First Embodiment)

[0049] The first embodiment is described below. In this embodiment, a magnetic sensor equipped with a magnetic field generator is described. The magnetic sensor measures (i.e., detects) an external magnetic field based on a high-frequency magnetic field generated by the magnetic field generator. Figure 1 As shown, the magnetic sensor is configured to include, in addition to the magnetic field generator 1, a diamond 2, a light source 3, a temperature control unit 4, a measurement unit 5, etc.

[0050] like Figures 1 to 3 As shown, the magnetic field generator 1 is constructed by arranging two annular upper coil 20 and lower coil 30 on the substrate 10 in an overlapping, layered manner. In the figures, the XY plane is a plane parallel to the surface of the substrate 10 (e.g., the upper surface), and the direction of the normal to the XY plane is parallel to the Z-axis. Furthermore, the magnetic field generator 1 is provided with an upper power supply 40 and a lower power supply 50. The upper power supply 40 is a mechanism for energizing the upper coil 20, and the lower power supply 50 is a mechanism for energizing the lower coil 30.

[0051] The substrate 10 supports the upper coil 20 and the lower coil 30. For example, the substrate 10 is made of an epoxy resin material or the like, and has a structure that includes the upper coil 20 and the lower coil 30 inside. A dielectric material, which is a portion of the substrate 10, is sandwiched between the upper coil 20 and the lower coil 30.

[0052] Here, the substrate 10 is configured as a multilayer substrate, which has an upper coil 20 and a lower coil 30 embedded therein by stacking and combining multiple printed circuit boards. For example, multiple printed circuit boards are prepared, each having a front surface and a back surface covered with metal foil (such as copper foil), some of which are patterned by etching to form the upper coil 20, the lower coil 30, etc. Then, the patterned printed circuit boards are combined / integrated by pressing or the like to form the substrate 10 in which the upper coil 20 and the lower coil 30 are embedded.

[0053] In addition, such as Figures 1 to 3 As shown, the substrate 10 has a through-hole 11 that penetrates the interior of the upper coil 20 and the lower coil 30. The through-hole 11 can be formed to penetrate both the front and rear surfaces of the substrate 10, in which case the through-hole 11 has a cylindrical shape. The diamond 2 and the temperature control unit 4, described later, are arranged in the through-hole 11.

[0054] Note that, although in Figure 1 and Figure 3 The text is omitted, but as... Figure 2 As shown, the upper coil 20 and the lower coil 30 are sandwiched between the front and rear surfaces of the substrate 10, and the upper GND layer 12 and the lower GND layer 13, which have a ground potential, are symmetrically arranged (hereinafter, "ground" can be designated as GND). In this way, a microstrip line is constructed by vertically and symmetrically arranging the upper GND layer 12 and the lower GND layer 13 on the substrate 10. The upper GND layer 12 and the lower GND layer 13 are formed to at least cover the coil portion 21 of the upper coil 20 and the coil portion 31 of the lower coil 30. Then, the upper GND layer 12 is partially removed, for example, at a location outside the coil portions 21 and 31, and the electrical connection between the upper power supply 40 and the upper coil 20 and the lower power supply 50 and the lower coil 30 are respectively achieved via the removed portion. Furthermore, a via 11 is formed to penetrate the upper GND layer 12 and the lower GND layer 13.

[0055] The upper coil 20 has a coil portion 21, a slit 22 that partially cuts out the coil portion 21, and a lead portion 23. The lead portion 23 is arranged on both sides of the slit 22 and extends outward in the outer circumferential direction of the coil portion 21. The coil portion 21 and the lead portion 23 are made of, for example, a first conductive material, such as copper as described above.

[0056] The coil portion 21 constitutes a ring circuit composed of a ring coil. Specifically, the coil portion 21 has a ring shape with a predetermined width, and the length of each ring (i.e., the electrical length of one ring) is set to one wavelength of the high-frequency current flowing from the upper power supply 40. That is, the distributed constant circuit is configured such that one wavelength and the electrical length of the high-frequency current are set to be approximately the same. When using a high-frequency current close to 2.87 GHz, one wavelength is approximately 100 mm. Therefore, the radius of the coil portion 21 is approximately 16 mm.

[0057] However, since the wavelength shortening rate varies depending on the material surrounding the coil (i.e., the dielectric constant of the substrate 10), the electrical length of each loop of the coil portion 21 can be set according to the wavelength shortening rate. For example, when FR4, which is made of glass epoxy resin, is used as the epoxy resin material, the dielectric constant is about 4, which makes the radius about 8 mm due to the wavelength shortening rate, and the length of each loop of the coil portion 21 is set to about 50 mm.

[0058] Usually, in Figure 4A The diagram illustrates the relationship between the physical and electrical lengths of wiring in a ring circuit when the dielectric constant of the substrate is the same. Figure 4A In this context, L represents the reference length, and 1L, 2L, 5L, and 10L represent lengths obtained by multiplying the reference length by a numerical magnification factor. Furthermore, in... Figure 4B The diagram illustrates the relationship between the dielectric constant of the substrate and the electrical length when the physical length of the wiring in a ring circuit is the same. Figure 4B In this context, εr represents the relative permittivity, and εr:1, εr:2, εr:5, εr:10, and εr:20 represent the numerical values ​​of the relative permittivity. As shown in these figures, the electrical length in the loop is proportional to the physical length, and the higher the permittivity, the longer the electrical length. Therefore, in this embodiment, the electrical length of each loop of the coil portion 21 composed of looped coils is set based on the physical length of the upper coil 20 corresponding to the wiring and the relative permittivity of the substrate 10.

[0059] The length of one loop of the coil portion 21 and the wavelength of one high-frequency current do not need to be perfectly matched. That is, if the XY plane can be oriented in the direction of the magnetic field when generating the high-frequency magnetic field, as will be described later, the length of one loop of the coil portion 21 and the wavelength of one high-frequency current can be different from each other. For example, a magnetic field is generated in the XY plane even if a deviation of ±20% occurs, but this deviation is preferably within ±10%. Furthermore, the aforementioned through-hole 11 has dimensions corresponding to the dimensions of the coil portion 21, and if the radius of the coil portion 21 is approximately 16 mm, the radius of the through-hole 11 is set to be smaller than that radius.

[0060] The slit 22 is a gap provided between one end and the other end of the coil portion 21, which can be, for example, a few tenths of a mm to a few mm, and the length of one loop of the coil portion 21 excluding the gap is set to the wavelength of the high-frequency current.

[0061] The lead portion 23 has a first lead portion 23a and a second lead portion 23b extending from one end of the coil portion 21. The first lead portion 23a is connected to the upper power supply 40, and the second lead portion 23b is connected to GND. As a result, a current path is formed for the current flowing from the upper power supply 40 from the first lead portion 23a through the coil portion 21 to the second lead portion 23b. Furthermore, in order to suppress the reflection of the current flowing from the second lead portion 23b to GND, a resistor 60 is provided at a position between the second lead portion 23b and GND.

[0062] The lower coil 30 has a shape corresponding to the upper coil 20. The lower coil 30 also has a coil portion 31, a slit 32 that partially cuts out the coil portion 31, and lead portions 33 arranged on both sides of the slit 32 and extending out / extending in the outer peripheral direction of the coil portion 31. The coil portion 31 and the lead portions 33 are made of, for example, a second conductive material, such as copper as described above.

[0063] The coil portion 31 constitutes a ring circuit composed of a ring coil. Specifically, the shape and size of the coil portion 31 are the same as those of the coil portion 21 of the upper coil 20, and it is arranged to face the coil portion 21 at a predetermined distance.

[0064] The slit 32 also has the same dimensions as the slit 22 of the upper coil 20. In this embodiment, the slit 32 is formed at the same location as the slit 22.

[0065] The lead portion 33 has a first lead portion 33a and a second lead portion 33b extending from one end of the coil portion 31. The first lead portion 33a is connected to the lower power supply 50, and the second lead portion 33b is connected to GND. In this way, a current path is formed for the current flowing from the lower power supply 50 from the first lead portion 33a through the coil portion 31 to the second lead portion 33b. Furthermore, in order to suppress the reflection of the current flowing from the second lead portion 33b to GND, a resistor 70 is provided at a position between the second lead portion 33b and GND.

[0066] The center of coil portion 21 of the upper coil 20 and the center of coil portion 31 of the lower coil 30 are aligned / matched, and their central axis is the Z-axis. The central axis can also be referred to as the coil central axis. Furthermore, between the upper coil 20 and the lower coil 30, a surface parallel to coil portion 21 and coil portion 31 is the XY plane.

[0067] Upper power supply 40 is a high-frequency power supply that supplies high-frequency current to upper coil 20. Upper power supply 40 generates a high-frequency current, one wavelength of which is the length of one loop of coil portion 21. Lower power supply 50 is a high-frequency power supply that supplies high-frequency current to lower coil 30. Lower power supply 50 generates a high-frequency current, one wavelength of which is the length of one loop of coil portion 31. Here, a high-frequency current of approximately 2.87 GHz passes through both upper power supply 40 and lower power supply 50.

[0068] The magnetic field generator 1 is configured as described above. Although details of the magnetic field generator 1 configured in this way will be described later, a high-frequency magnetic field is generated in the XY plane located between the upper coil 20 and the lower coil 30.

[0069] Diamond 2 corresponds to a magnetic field measuring element for measuring an external magnetic field and is arranged in through-hole 11. Diamond 2 is positioned in the XY plane to generate a high-frequency magnetic field at a location between upper coil 20 and lower coil 30. When diamond 2 is irradiated with light of a specific wavelength and when a high-frequency magnetic field is applied to it, diamond 2 undergoes wavelength conversion to produce fluorescence.

[0070] The light source 3 uses a laser beam as light with a specific wavelength to irradiate the diamond 2. The light source 3 is arranged outside the substrate 10, that is, outside the upper coil 20 and the lower coil in the radial direction, and irradiates the diamond 2 with light through the space between the upper coil 20 and the lower coil. Here, for example, the light source 3 is arranged such that the laser irradiates along the XY plane. However, the light source 3 can also be arranged such that the laser irradiates at an angle relative to the XY plane. For example, a green laser beam is output from the light source 3, and its wavelength is converted by the diamond 2 to produce red fluorescence.

[0071] Temperature control unit 4 is used to regulate the temperature of diamond 2. Temperature control unit 4 is arranged in contact with diamond 2. Diamond 2 fluoresces by changing the wavelength of the irradiated light, during which energy loss occurs and heat is generated. Temperature control unit 4 regulates the temperature of diamond 2 by cooling it or by other methods when heat is generated.

[0072] The measurement unit 5 is used to measure the light emitted by the diamond 2 and is composed of a light-receiving element, etc. As described above, when the diamond 2 emits fluorescence, the fluorescence is output in all directions. Therefore, by arranging the measurement unit 5 outside the through-hole 11, the measurement unit 5 can measure the light emission of the diamond 2. Then, the measurement unit 5 measures the light emitted by the diamond 2 to observe physical phenomena such as the shape of the diamond 2. Since the diamond 2 absorbs energy caused by the unpaired electrons of the measurement target based on ESR and changes its properties, the small magnetic field generated by the measurement target becomes measurable through / via the measurement physical phenomena.

[0073] The magnetic sensor including the magnetic field generator 1 according to this embodiment is configured as described above. As described above, the magnetic field generator 1 according to this embodiment generates a high-frequency magnetic field, and the diamond 2 can be used as a measuring element to measure an external magnetic field. At this time, the magnetic field generator 1 is configured to generate a high-frequency magnetic field having a magnetic field direction aligned in the XY plane, and furthermore, since the substrate 10 is thin, the minute magnetic field generated by the measurement target becomes measurable on the front and rear surfaces above and below the substrate 10. In addition, since the through hole 11 is formed by hollowing out the substrate 10, the measurement target, which serves as a source of minute magnetic fields, can be closer to the diamond 2 or the high-frequency magnetic field, thereby enabling more accurate measurement of the minute magnetic field.

[0074] Here, compared to conventional structures, a mechanism is described that allows the magnetic field direction of a high-frequency magnetic field to be set in the XY plane as described above.

[0075] As described above, the magnetic field generator 1 of this embodiment has an upper coil 20 and a lower coil 30 arranged in an overlapping manner, which receive high-frequency current supplies from an upper power supply 40 and a lower power supply 50, respectively. Furthermore, when viewed from the normal direction of the substrate 10, the lead portion 23 of the upper coil 20 and the lead portion 33 of the lower coil 30 are arranged in the same position. In this configuration, a high-frequency current with a 180° phase difference is applied to the upper coil 20 and the lower coil 30. The frequency of the high-frequency current is then set to approximately 2.87 GHz, such that one wavelength of the high-frequency current is substantially equal to the length of one loop of the coil portion 21 of the upper coil 20 and the coil portion 31 of the lower coil 30.

[0076] In the following description, at the moment when the high-frequency current is supplied, the phase of the high-frequency current at the ends (i.e., lead portions) of the input high-frequency current in the coil portion 21 of the upper coil 20 and the coil portion 31 of the lower coil 30 is referred to as the initial phase.

[0077] When such a high-frequency current passes through, for example, in the lower coil 30, such as Figure 5A and Figure 6 As shown, a high-frequency current is transferred (i.e., flows) from the first lead portion 33a to the second lead portion 33b. In this case, at point P1 (0°, the location of the first lead portion 33a) and point P2 (360°, the location of the second lead portion 33b), the polarity of the current is reversed at points symmetrical about the central axis of the coil. For example, suppose the waveform of the high-frequency current flowing at each position from 0° to 360° at any given time is as follows: Figure 7 As shown, the phase reverses at points P3 and P4, and the directions of the currents become opposite to each other. Therefore, for example, in Figure 5AAt position points P3 (90°) and P4 (270°), when viewed from the first lead portion 33a and the second lead portion 33b, counterclockwise magnetic fields E1 and E2 are generated based on the right-hand screw rule.

[0078] On the other hand, since a high-frequency current with a phase difference of 180° from the lower coil 30 is transmitted to the upper coil 20, a magnetic field opposite to that of the lower coil 30 is generated in the upper coil 20. Therefore, for example, when the magnetic fields at points P3 and P4 are shown, the upper coil 20 has clockwise magnetic fields E3 and E4 generated therein, and the lower coil 30 has counterclockwise magnetic fields E1 and E2 generated therein, respectively as follows: Figure 5B and Figure 6 As shown.

[0079] Therefore, at / around points P3 and P4 in the substrate 10, or in other words, at the location between the upper coil 20 and the lower coil 30, the directions of magnetic fields E1 to E4 are matched (i.e., aligned) with each other. Specifically, (A) magnetic fields E1 and E3 have the same direction at the lower part of the upper portion of the upper coil 20 (i.e., near the lower coil 30) and the upper part of the lower portion of the lower coil 30 (i.e., near the upper coil 20), and (B) magnetic fields E2 and E4 have the same direction at the lower part of the upper portion of the upper coil 20 (i.e., near the lower coil 30) and the upper part of the lower portion of the lower coil 30 (i.e., near the upper coil 20). In this way, a high-frequency magnetic field H is generated between the upper coil 20 and the lower coil 30, with the direction from point P4 to point P3 as the magnetic field direction, as shown below. Figure 5B As indicated by the white arrows in the diagram. Since the current flowing in the upper coil 20 and the lower coil 30 is a high-frequency current, the positions where the current amplitude reaches its maximum value and the positions where the current amplitude reaches its minimum value change respectively, thereby generating a high-frequency magnetic field with a corresponding change in the direction of the magnetic field in the XY plane.

[0080] As Figure 8 The comparative example shown considers the case where direct current flows through a structure in which a coil J20, wound multiple times, is provided in the substrate J10. In this configuration, the current reverses at positions symmetrical about the central axis of the coil. Therefore, as shown in the figure ( Figure 8As shown in the figure, a counterclockwise magnetic field EJ1 is generated at the position on the left side of the figure. At this position, in each of the multiple windings of coil J20, the current in coil J20 flows in a direction rising from the back of the paper toward the reader. Furthermore, a clockwise magnetic field EJ2 is generated at the position on the right side of the figure. At this position, the current flows in a direction away from the reader and into the paper. Therefore, a high-frequency magnetic field HJ is generated in coil J20 in the direction of the coil's central axis. In this case, the measurement target needs to be arranged on the lateral side of the substrate J10, that is, on the outer side of the coil J20 in the radial direction. Due to the above structure, this may limit the proximity of the measurement target relative to the coil J20. Furthermore, if the measurement target is placed directly above or below the substrate J10, that is, in the axial direction of the coil J20, the external magnetic field is measurable even though the distance to the measurement target is shorter, because the magnetic sensor is not sensitive in the axial direction.

[0081] Therefore, it can be said that, as in this embodiment, it is effective to use a magnetic field generator 1 that can make the XY plane align with the magnetic field direction.

[0082] As described above, in the magnetic field generator 1 of this embodiment, the upper coil 20 and the lower coil 30 are arranged to supply high-frequency current from the upper power supply 40 and the lower power supply 50, respectively. Furthermore, when viewed from the normal direction of the substrate 10, the lead portion 23 of the upper coil 20 and the lead portion 33 of the lower coil 30 are arranged in the same position. In this configuration, a high-frequency current with a 180° phase difference passes through the upper coil 20 and the lower coil 30. The length of one wavelength of the high-frequency current is set to be substantially equal to the length of one loop of the coil portion 21 of the upper coil 20 and the coil portion 31 of the lower coil 30.

[0083] In this configuration, the direction of the magnetic field generated on the side of the lower coil 30 of the upper portion of the substrate 10 in which the upper coil 20 is disposed is matched with the direction of the magnetic field generated on the side of the upper coil 20 of the lower portion of the substrate 10 in which the lower coil 30 is disposed. This allows a high-frequency magnetic field with the XY plane as the magnetic field direction to be generated at a position between the upper coil 20 and the lower coil 30.

[0084] Therefore, the magnetic sensor with this magnetic field generator 1 is configured to have sensitivity in the axial direction of the upper coil 20 and the lower coil 30, and to generate a very small magnetic field near the measurement target directly / above or directly / below the substrate 10. This makes the magnetic sensor more accurate.

[0085] Furthermore, the magnetic field generator 1 in this embodiment includes an upper power supply 40 that supplies high-frequency current to the upper coil 20 and a lower power supply 50 that supplies high-frequency current to the lower coil 30. Therefore, high-frequency currents with opposite phases can be supplied to the upper coil 20 and the lower coil 30 from the upper power supply 40 and the lower power supply 50, respectively.

[0086] Specifically, regarding the magnetic field generator 1 of this embodiment, the current flow in the upper coil 20 and the lower coil 30, as well as the generated high-frequency magnetic field, were studied through simulation. As a result, [the following was obtained]. Figures 9A to 9C The diagram shown in Figure 10.

[0087] When a high-frequency current passes through the upper coil 20 and the lower coil 30, and the high-frequency current has opposite phases with a 180° phase difference, Figures 9A to 9C Arrows indicate the current direction at various points in the coil at any given time. That is, in the upper coil 20, the current directions are opposite at points symmetrical about the coil's central axis. Similarly, in the lower coil 30, the current directions are opposite at points symmetrical about the coil's central axis. Furthermore, at the same angular position relative to the coil's central axis, the currents in the upper coil 20 and the lower coil 30 flow in opposite directions. Then, as... Figure 9C As shown, in the upper coil 20, current is generated from any position on the side opposite to the lead portion 23 relative to the coil's central axis, and in the lower coil 30, current flows into any / arbitrary position on the side opposite to the lead portion 23 relative to the coil's central axis.

[0088] Therefore, in Figure 10 In the cross-sectional diagram shown, the upper coil 20 generates a clockwise magnetic field, and the lower coil 30 generates a counterclockwise magnetic field. Therefore, as... Figure 10 As shown, a high-frequency magnetic field pointing to the left side of the paper can be generated at the location of diamond 2, indicating that a high-frequency magnetic field can be generated in the XY plane.

[0089] (Second Embodiment)

[0090] The second embodiment is described. In this embodiment, the construction of the upper coil 20 and the lower coil 30 differs from that of the first embodiment, while other parts are the same as those of the first embodiment. Therefore, this difference will be described in detail.

[0091] like Figure 11 and Figure 12 As shown, in this embodiment, both the upper coil 20 and the lower coil 30 in the magnetic field generator 1 have a double-layer structure. That is, the upper coil 20 is composed of a first coil 210 and a second coil 220, and the lower coil 30 is composed of a third coil 310 and a fourth coil 320.

[0092] The first coil 210 is configured to have a coil portion 211, a slit 212, and a lead portion 213. The coil portion 211, the slit 212, and the lead portion 213 including the first lead portion 213a and the second lead portion 213b have the same construction as the coil portion 21, the slit 22, and the lead portion 23 described in the first embodiment. Furthermore, the second coil 220 is configured to have a coil portion 221, a slit 222, and a lead portion 223. The coil portion 221, the slit 222, and the lead portion 223 including the first lead portion 223a and the second lead portion 223b have the same construction as the coil portion 21, the slit 22, and the lead portion 23 described in the first embodiment. However, here, the positions of the slit 212 and the lead portion 213 of the first coil 210 are different from the positions of the slit 222 and the lead portion 223 of the second coil 220, and these positions are offset by 180° relative to the central axis of the coil.

[0093] Furthermore, the upper power supply 40 includes a first upper power supply 41 and a second upper power supply 42. The first upper power supply 41 is connected to the first lead portion 213a to energize the first coil 210, and the second upper power supply 42 is connected to the first lead portion 223a to energize the second coil 220.

[0094] In addition, a resistor 61 is provided to connect the second lead portion 213b to GND for reflection suppression, and a resistor 62 is provided to connect the second lead portion 223b to GND for reflection suppression.

[0095] The third coil 310 is configured to have a coil portion 311, a slit 312, and a lead portion 313 having a first lead portion 313a and a second lead portion 313b. The coil portion 311, slit 312, and lead portion 313 have the same construction as the coil portion 31, slit 32, and lead portion 33 described in the first embodiment. Furthermore, the fourth coil 320 is configured to have a coil portion 321, a slit 322, and a lead portion 323 having a first lead portion 323a and a second lead portion 323b. The coil portion 321, slit 322, and lead portion 323 have the same construction as the coil portion 31, slit 32, and lead portion 33 described in the first embodiment. However, here, the positions of the slit 312 and lead portion 313 of the third coil 310 are different from the positions of the slit 322 and lead portion 323 of the fourth coil 320, and these positions are offset by 180° relative to the central axis of the coil.

[0096] Furthermore, the lower power supply 50 includes a first lower power supply 51 and a second lower power supply 52. ​​The first lower power supply 51 is connected to the first lead portion 313a to energize the third coil 310, and the second lower power supply 52 is connected to the first lead portion 323a to energize the fourth coil 320.

[0097] In addition, a resistor 71 is provided to connect the second lead portion 313b to GND for reflection suppression, and a resistor 72 is provided to connect the second lead portion 323b to GND for reflection suppression.

[0098] In this configuration, high-frequency current passes through the first coil 210 and the second coil 220 that constitute the upper coil 20, so that the currents at the same angle relative to the central axis of the coils are in phase. That is, relative to the first coil 210 and the second coil 220, since the positions of the lead portion 213 and the lead portion 223 are offset by 180°, the phase of the high-frequency current to be passed is also offset by 180°.

[0099] Furthermore, a high-frequency current with the same phase at the same angle relative to the central axis of the coil also passes through the third coil 310 and the fourth coil 320 constituting the lower coil 30. However, for the third coil 310 and the fourth coil 320, a high-frequency current with a 180° phase difference from the first coil 210 and the second coil 220 is provided. That is, since the positions of the lead portions 313 and 323 of the third coil 310 and the fourth coil 320 are also offset by 180°, the phase of the high-frequency current to be passed is also offset by 180°. Furthermore, regarding the third coil 310, since the lead portion 313 is arranged at the same angle as the lead portion 213 of the first coil 210, the high-frequency current is 180° out of phase with respect to the first coil 210. Similarly, regarding the fourth coil 320, since the lead portion 323 is arranged at the same angle as the lead portion 223 of the second coil 220, the high-frequency current is 180° out of phase with respect to the second coil 220.

[0100] In this way, such as Figure 12 As shown, magnetic fields E3 and E4 in the same direction can be generated at the same angle relative to the central axis of the coils in the first coil 210 and the second coil 220. Furthermore, magnetic fields E1 and E2 in opposite directions can be generated at the same angle relative to the central axis of the coils in the third coil 310 and the fourth coil 320, respectively.

[0101] Therefore, even if the upper coil 20 and the lower coil 30 consist of two layers, a high-frequency magnetic field H with the XY plane as the magnetic field direction can be generated between the upper coil 20 and the lower coil 30. If the upper coil 20 and the lower coil 30 are composed of two layers in this way, the magnetic field strength generated by the upper coil 20 and the lower coil 30 can be increased, and a stronger high-frequency magnetic field can be generated.

[0102] (Third Embodiment)

[0103] The third embodiment is described. This embodiment is a modification of the layout of the upper coil 20 and the lower coil 30 in the first embodiment, but has the same configuration as the first embodiment for other parts. Therefore, the differences will be described in detail.

[0104] like Figure 13 and 14 As shown, in this embodiment, the formation positions of the slit 22 and lead portion 23 of the upper coil 20 are different from those of the slit 32 and lead portion 33 of the lower coil 30. Here, the formation positions of the slit 22 and lead portion 23 of the upper coil 20 and the slit 32 and lead portion 33 of the lower coil 30 are offset by 90° relative to the central axis of the coil. Specifically, assuming that the position of the first lead portion 23a in the upper coil 20 is 0° and the position of the second lead portion 23b is 360°, then the slit 32 and lead portion 33 in the lower coil 30 are arranged at 270°.

[0105] In this configuration, the initial phase of the high-frequency current flowing through the upper coil 20 is set to 90°, and the initial phase of the high-frequency current flowing through the lower coil 30 is set to 0°. In this way, the phase of the high-frequency current in the upper coil 20 and the lower coil 30 can be offset by the same angle of 180° relative to the central axis of the coils.

[0106] Therefore, even if the formation positions of the slit 22 and lead portion 23 of the upper coil 20 and the formation positions of the slit 32 and lead portion 33 of the lower coil 30 have different angles relative to the coil central axis, i.e., they do not have the same angles, the same effect as the first embodiment can be obtained.

[0107] Here, the positions where the slit 22 and lead portion 23 of the upper coil 20 are formed, and the positions where the slit 32 and lead portion 33 of the lower coil 30 are formed, are offset by 90° relative to the central axis of the coil. However, the offset angle may not be 90°.

[0108] (Fourth Embodiment)

[0109] The fourth embodiment is described. In this embodiment, the shapes of the upper coil 20 and the lower coil 30 are changed relative to the first to third embodiments, while other parts are the same as in the first to third embodiments. Therefore, only the parts that differ from the first to third embodiments are described.

[0110] like Figure 15 and 16 As shown, in this embodiment, the coil portion 21 of the upper coil 20 and the coil portion 31 of the lower coil 30 are not annular but square. Specifically, the coil portion 21 is formed into a rectangular shape consisting of two opposing short sides and two opposing long sides, and the slit 22 and the lead portion 23 are arranged on one short side. Similarly, the coil portion 31 is formed into a rectangular shape consisting of two opposing short sides and two opposing long sides, and the slit 32 and the lead portion 33 are arranged on one short side. The coil portions 21 and 31 are arranged facing each other, so that their short sides overlap each other and their long sides overlap each other (in the plan view).

[0111] Slit 22, lead portion 23, slit 32, and lead portion 33 can be arranged at the same angle relative to the central axis of the coil as in the first embodiment. However, in this embodiment, they are arranged at a position offset by 180°. In this arrangement, a high-frequency current with an initial phase of 0° can pass through the upper coil 20 and the lower coil 30.

[0112] In this way, even when coil portion 21 and coil portion 31 have a quadrilateral shape, the same effect as the first embodiment can be achieved if the length of each loop is set to one wavelength of the high-frequency current flowing through them.

[0113] Furthermore, when coil sections 21 and 31 have a rectangular shape, the direction of the magnetic field is controllable by adjusting the aspect ratio (which is the ratio of the vertical dimension to the horizontal dimension of the rectangular shape in the XY plane). When coil sections 21 and 31 have a rectangular shape, the aspect ratio corresponds to the ratio of the long side to the short side. In this configuration, a weak high-frequency magnetic field can be generated along the long side in the direction of arrow E, and a strong high-frequency magnetic field can be generated along the short side in the direction of arrow F. Therefore, the direction of the magnetic field can be controlled essentially in the direction of arrow F.

[0114] (Fifth Embodiment)

[0115] The fifth embodiment is described. This embodiment is similar to the first to fourth embodiments in that the form of the high-frequency current input to the upper coil 20 and the lower coil 30 changes from the first to the fourth embodiments. Therefore, this embodiment only describes the parts that differ from the first to fourth embodiments.

[0116] like Figure 17As shown, in the magnetic field generator 1 of this embodiment, a phase adjuster 80 for adjusting the phase of the high-frequency current flowing through the upper coil 20 and a phase adjuster 90 for adjusting the phase of the high-frequency current flowing through the lower coil 30 are provided. Then, the phase adjuster 80 adjusts the phase of the high-frequency current output from the upper power supply 40, and the high-frequency current with the same phase reaches both ends of the coil section 21 through both the first lead portion 23a and the second lead portion 23b. Similarly, the phase adjuster 90 adjusts the phase of the high-frequency current output from the lower power supply 50, and the high-frequency current with the same phase reaches both ends of the coil section 31 through both the first lead portion 33a and the second lead portion 33b.

[0117] In the magnetic field generator 1 configured in this way, standing waves can be generated by a high-frequency current flowing through the upper coil 20 and the lower coil 30. For example, as Figure 17 and 18 As shown, to illustrate the phase, the upper coil 20 has four points G to K, spaced substantially 90° apart from each other relative to the coil's central axis, from one end on the first lead portion 23a side to the other end on the second lead portion 23b side. In this case, for example, high-frequency currents are supplied as input I and input II to both ends of the coil portion 21, and the phase difference between the high-frequency currents is set to 0° (i.e., there is no phase difference between input I and II). In this way, as... Figure 19A As shown, a standing wave with maximum amplitude can be generated by a high-frequency current. This standing wave has positions G, I, and K as nodes and positions H and J as antinodes. In this case, a high-frequency magnetic field can be generated with the magnetic field direction repeating alternately between two directions: that is, from point H to point J and from point J to point H.

[0118] Furthermore, for example, when the phase difference of the high-frequency current flowing from both ends of the coil section 21 is set to 180°, such as Figure 19B As shown, a standing wave can be generated with points G, I, and K as antinodes and points H and J as nodes. In this case, a high-frequency magnetic field can be generated with the magnetic field direction repeating and alternating between two directions: from point G or K to point I and from point I to point G or K.

[0119] Furthermore, although it has been referenced Figure 18 , Figure 19A and Figure 19BAn example of the upper coil 20 has been described, but this also applies to the lower coil 30. Standing waves with a 180° phase difference are then formed in both the upper coil 20 and the lower coil 30. In this way, matching between the two magnetic field directions can be achieved. That is, the direction of the magnetic field generated on the side of the lower coil 30 in the upper portion of the substrate 10 in which the upper coil 20 is disposed is matched with the direction of the magnetic field generated on the side of the upper coil 20 in the lower portion of the substrate 10 in which the lower coil 30 is disposed. Therefore, a high-frequency magnetic field with the XY plane as the magnetic field direction can be generated.

[0120] In this way, standing waves can be generated by allowing high-frequency current to flow from both ends of the upper coil 20 and the lower coil 30. Therefore, while confining the magnetic field direction to a certain direction, a high-frequency magnetic field with alternating magnetic field directions of 180° can be generated in the XY plane.

[0121] Note that in this disclosure, the phase modulator 80, which generates a high-frequency current input from both the first lead portion 23a and the second lead portion 23b based on a signal source of the upper power supply 40, can be modified. That is, the phase modulator 80 can not only adjust the phase based on a single signal and split it into two signals, but also use the two signals to adjust the phase of each signal and output the adjusted signal as a high-frequency current. Of course, the same applies to the phase modulator 90.

[0122] (Sixth Embodiment)

[0123] The sixth embodiment is described. This embodiment is similar to the first to fourth embodiments in that the form of the high-frequency current input to the upper coil 20 and the lower coil 30 changes from the first to the fourth embodiments. Therefore, this embodiment only describes the parts that differ from the first to fourth embodiments.

[0124] In the magnetic field generator 1 of this embodiment, as Figure 20A and 20B As shown, a further modification to the same configuration as the first embodiment is made to allow the input direction of the high-frequency current to the upper coil 20 to be switchable, thereby allowing clockwise and counterclockwise rotation of the magnetic field direction as a circularly polarized wave. For example, as Figure 20A and 20B As shown, an input switching switch 100 is provided between the upper coil 20 and the upper power supply 40 and resistor 60 to switch the input terminal of the upper coil 20 that receives high-frequency current input. Furthermore, although not shown, the lower coil 30, like the upper coil 20, also has an input switching switch 100 provided between the lower coil 30 and the lower power supply 50 or resistor 70 to switch the high-frequency current input.

[0125] In this way, the rotation direction of the magnetic field in the XY plane can be controlled. For example, a high-frequency current is input to the upper coil 20 from the first lead portion 23a, and in order to input a high-frequency current from the first lead portion 33a, a 180° phase difference is added relative to the upper coil 20 to the lower coil 30. In this case, as... Figure 20A As shown, the direction of the magnetic field can rotate to the right (i.e., clockwise) from point M to point L. Conversely, a high-frequency current is input from the second lead portion 23b to the upper coil 20, and in order to input the high-frequency current from the second lead portion 33b, a 180° phase difference is added relative to the upper coil 20 to the lower coil 30. In this case, as... Figure 20B As shown, the direction of the magnetic field can rotate to the left (i.e., counterclockwise) from point L to point M.

[0126] Specifically, in magnetic sensors using diamond NVC, circularly polarized waves are used for high-frequency magnetic fields, and by switching the direction of the circularly polarized waves, unpaired electrons can be selectively pumped to either of the degeneracy values ​​MS = ±1. In this way, a high-sensitivity magnetic sensor with excellent minimum resolution can be realized.

[0127] (Seventh Embodiment)

[0128] The seventh embodiment is described. In this embodiment, the upper coil 20 is changed to a resonant coil compared to the first to sixth embodiments, and the other parts are the same as the first to sixth embodiments. Therefore, only the parts that are different from the first to sixth embodiments are described in this embodiment. Hereinafter, as an example, the coil portion 21 of the upper coil 20 and the coil portion 31 of the lower coil 30 are described as having a ring shape as in the first embodiment. However, the configuration shown in the second to sixth embodiments is also possible.

[0129] like Figure 21 , Figure 22 and Figure 23 As shown, the upper coil 20 consists only of coil portion 21 and slit 22, and no high-frequency current is supplied to the upper coil 20 from the power supply. Therefore, the high-frequency current is supplied only from the power supply 50 to the lower coil 30. In this configuration, when the high-frequency current passes through the lower coil 30, the upper coil 20 is magnetically or field-coupled to the lower coil 30, and the upper coil 20 functions as a resonant coil to generate LC resonance. Therefore, the resonant frequency of the upper coil 20 is tuned so that the length of each loop of coil portion 31 corresponds to a wavelength. That is, the frequency at which the electrical length of coil portion 31 is converted to a wavelength is set as the resonant frequency.

[0130] A magnetic field generator 1 with this structure can also be used. In this structure, when a high-frequency current passes through the lower coil 30, the currents in the upper coil 20 and the lower coil 30, which are at the same angle relative to the central axis of the coils, can be controlled to flow in opposite directions based on LC resonance. Therefore, as in the first embodiment, a high-frequency magnetic field can be generated such that the XY plane between the upper coil 20 and the lower coil 30 serves as the direction of the magnetic field. Thus, the same effect as in the first embodiment can be achieved.

[0131] Although a slit 22 is formed in the upper coil 20, it is not necessary to form a slit 22, or multiple slits 22 can be formed. The number of slits 22 and the size of the gap can be appropriately set so that the resonant frequency based on LC resonance matches the frequency of each loop of the coil section 21, which is one wavelength in length.

[0132] Furthermore, this embodiment can also be applied to a construction for generating standing waves of high-frequency current, as in the fifth embodiment. In this case, the construction may include a phase adjuster 90 that supplies high-frequency current from both ends of the coil portion 31 of the lower coil 30.

[0133] Furthermore, this embodiment can also be applied to the construction of the sixth embodiment. In this case, since the high-frequency current is not directly supplied from the power supply to the upper coil 20, which serves as a resonant coil, the structure equipped with the input switching switch 100 can be applied to the lower coil 30.

[0134] For reference, regarding the magnetic field generator 1 of this embodiment, the current flow and the generated high-frequency magnetic field in the upper coil 20 and lower coil 30 were studied through simulation. Results were obtained. Figure 24 and Figure 25 The simulation results are shown.

[0135] When a high-frequency current passes through the lower coil 30, at any given moment, the direction of the current in each part of the upper coil 20 and the lower coil 30 changes from... Figure 24 The arrows indicate this. That is, in the lower coil 30, the current direction is opposite at a point symmetrical with respect to the coil's central axis. Furthermore, by allowing high-frequency current to flow through the lower coil 30, high-frequency current also flows through the upper coil 20, and even in the upper coil 20, at a point symmetrical with respect to the coil's central axis, the current direction is opposite. Moreover, at the same angular position relative to the coil's central axis, the current in the upper coil 20 and the lower coil 30 flows in opposite directions. Then, as... Figure 24As shown, the upper coil 20 is in a state where current is generated from any position on the side of the slit 22, and the lower coil 30 is in a state where current flows into any position on the side of the lead portion 33. Although the arrow indicating the direction of current is shown as protruding from the upper coil 20 on the side of the upper coil 20 opposite to the slit 22 relative to the coil's central axis, the current actually flows from the upper end face of the upper coil 20 towards... Figure 24 The flow extends from the upper right corner to its side surface.

[0136] Therefore, in Figure 25 In the cross-section shown, the upper coil 20 generates a clockwise magnetic field, and the lower coil 30 generates a counterclockwise magnetic field. Therefore, as... Figure 25 As shown, it can be seen that (a) a high-frequency magnetic field can be generated in the left direction of the paper at the position of diamond 2, and (b) a high-frequency magnetic field can be generated in the XY plane.

[0137] (Other embodiments)

[0138] Although this disclosure has been described with reference to the above embodiments, it is not limited to these embodiments, but may include various changes and modifications within the equivalent scope. Furthermore, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and concept of this disclosure.

[0139] For example, in each of the above embodiments, a structure in which the upper coil 20 and the lower coil 30 are disposed and integrated in a substrate 10 is given as an example. However, this is only an example, and the substrate 10 can be divided into multiple sheets / layers and can have a structure in which an upper portion having the upper coil 20 and a lower portion having the lower coil 30 can be separately disposed, and a dielectric film can be sandwiched between them. In this case, at least a portion of the substrate 10 between the upper coil 20 and the lower coil 30 can be made of / filled with a dielectric material.

[0140] Furthermore, although the second embodiment has described the case where the upper coil 20 and the lower coil 30 each have two layers, each of the coils 20 and 30 may have only one layer or multiple layers, that is, it may have two or more layers. The number of layers in the upper coil 20 and the lower coil 30 may be the same or different. Moreover, even in a structure where the upper coil 20 and the lower coil 30 have one or more layers, as described in the third embodiment, the slit and lead portions may be arranged at different angles relative to the coil's central axis.

[0141] Furthermore, in the fourth embodiment, a rectangular shape is given as an example of the case where the coil portion 21 of the upper coil 20 and the coil portion 31 of the lower coil 30 can have polygonal shapes. However, this is only an example, and the shape of the coil portion can also be a quadrilateral other than a rectangle, such as a rhombus, or a polygon other than a quadrilateral, such as a triangle or a pentagon. Of course, the circular / ring shape can also be an elliptical shape, or each corner of the polygonal shape can be rounded. In the first to third and fifth to seventh embodiments, since the coil portion 21 of the upper coil 20 and the coil portion 31 of the lower coil 30 are formed into a ring shape, the aspect ratio of the vertical / horizontal dimensions of the coil shape in the XY plane is 1:1 when assuming that one direction of the XY plane is the vertical direction and the other direction perpendicular to it is the horizontal direction. However, if the coil portion 21 and the coil portion 31 have elliptical shapes, the aspect ratios can be different, and a strong high-frequency magnetic field can be generated along the direction with the smaller aspect ratio. Of course, even when coil portion 21 and coil portion 31 have polygonal shapes other than rectangles, a strong high-frequency magnetic field can be generated in the direction along the side with a smaller aspect ratio (i.e., by making the aspect ratio different from 1:1).

[0142] Furthermore, in each of the above embodiments, examples have been described as follows: (a) the first conductive material constituting the upper coil 20 and the second conductive material constituting the lower coil 30 are copper, and (b) the material of the substrate 10 is an epoxy resin material. However, such configurations are merely examples, and other materials may also be used. It is preferable that the upper coil 20 and the lower coil 30 are made of the same material, but different materials may also be used.

[0143] Furthermore, in each of the above embodiments, an example of diamond 2 as a magnetic field measuring element has been described, but objects other than diamond 2 can also be used. Furthermore, in each of the above embodiments, the application of the magnetic field generator 1 to a magnetic sensor that receives fluorescence by irradiating it with a laser beam has been described. However, it can also be applied to methods that (a) obtain an electrical signal by irradiating a laser beam or (b) obtain an electrical output by inputting an electrical signal. That is, it can be applied to PDMR (photocurrent detection magnetic resonance), EDMR (electro-detection magnetic resonance), etc.

[0144] In each of the above embodiments, the terms "upper" and "lower" are used for the upper coil 20 and the lower coil 30, but only the coils constituting the two ring circuits are shown overlapping and arranged at a predetermined distance, and do not imply the orientation of the top and bottom.

Claims

1. A magnetic field generator, comprising: The upper coil (20) is made of a first conductive material and forms a ring circuit with a coil portion (21); The lower coil (30) is made of a second conductive material and forms a ring circuit with a coil portion (31), which is arranged opposite to the coil portion of the upper coil at a predetermined distance; A substrate (10) that supports the upper coil and the lower coil and has a dielectric material located between the upper coil and the lower coil; as well as A grounding layer having a ground potential is arranged to sandwich the upper coil and the lower coil between one surface and another surface of the substrate; An upper-level power supply that supplies high-frequency current to the upper-level coil; as well as The lower power supply provides a high-frequency current with a phase opposite to that supplied to the upper coil, wherein... High-frequency currents of opposite phase pass through the upper coil and the lower coil, respectively, and The length of each loop in the upper coil and the lower coil is matched to one wavelength of the high-frequency current.

2. The magnetic field generator as described in claim 1, wherein... The coil portion of at least one of the upper coil and the lower coil is made of a plurality of coils facing each other at a predetermined distance.

3. The magnetic field generator as described in claim 1 or 2, wherein... The plane parallel to the coil portions of the upper and lower coils and located between the upper and lower coils is designated as the XY plane, where one direction is referred to as the vertical direction and the other direction as the horizontal direction. The coil portion of the upper coil or the lower coil has an aspect ratio of 1 with respect to the dimensions along the vertical and horizontal dimensions.

4. The magnetic field generator as described in claim 1 or 2, wherein... The plane parallel to the coil portions of the upper and lower coils and located between the upper and lower coils is designated as the XY plane, where one direction is referred to as the vertical direction and the other direction as the horizontal direction. The coil portion of the upper coil or the lower coil has an aspect ratio that is not 1 with respect to the dimensions along the vertical and horizontal dimensions.

5. The magnetic field generator as claimed in claim 1 or 2, wherein each of the upper coil (20) and the lower coil (30) includes a lead portion connected to GND, and a resistor (60, 70) is provided at a location between the lead portion and GND.

6. The magnetic field generator as described in claim 5, further comprising: A slit (22) is formed in the coil portion of the upper coil, and a high-frequency current from the upper power supply is supplied to one of the two ends of the coil portion formed by the slit; A slit (32) is formed in the coil portion of the lower coil, and a high-frequency current from the lower power supply is supplied to one of the two ends of the coil portion formed by the slit; An input switching switch (100) is used to switch the high-frequency current from the upper power supply to one of the two ends of the coil portion of the upper coil. as well as An input switching switch (100) is used to switch the high-frequency current from the lower power supply to flow to one of the two ends of the coil portion of the lower coil.

7. The magnetic field generator as described in claim 5, further comprising: A phase adjuster (80) is used to generate a standing wave of high-frequency current in the upper coil by supplying a high-frequency current from the upper power supply to the two ends of the coil section formed by the slit (22); as well as A phase adjuster (90) is used to generate a standing wave of high-frequency current in the lower coil by supplying a high-frequency current from the lower power source to the two ends of the coil portion formed by the slit (32).

8. The magnetic field generator as claimed in claim 1 or 2, wherein... The upper coil is a resonant coil that is magnetically or electrically coupled to the lower coil. The lower power supply (50) is configured to supply high-frequency current to the lower coil, and By supplying a high-frequency current to the lower coil, a high-frequency current having an opposite phase to the high-frequency current supplied to the lower coil flows through the upper coil.

9. The magnetic field generator as claimed in claim 8, wherein... A slit (32) is formed in the coil portion of the lower coil, and a high-frequency current from the power source is supplied to one end of the coil portion formed by the slit. An input switching switch (100) is provided for switching which end of the coil portion of the lower coil receives the high-frequency current supply from the power source.

10. The magnetic field generator of claim 8, wherein... A slit (32) is formed in the coil portion of the lower coil, and A phase adjuster (90) is provided to generate a standing wave of high-frequency current in the lower coil when a high-frequency current is supplied from the power source to the two ends of the coil portion formed by the slit.

11. A magnetic sensor, comprising: The magnetic field generator as described in claim 1 or 2, wherein The substrate has a through hole (11) that penetrates the front and rear surfaces of the substrate and passes through the inner side of the coil portions of the upper and lower coils, and The magnetic field measuring element (2) is arranged in the through hole (11) and measures the external magnetic field, and The light source (3) illuminates the magnetic field measuring element with light of a specific wavelength.

12. The magnetic sensor of claim 11, further comprising: The measuring unit (5) is disposed in the magnetic field measuring element for receiving wavelength-converted light from the irradiated light.

13. The magnetic field generator as claimed in claim 8, wherein... The plane parallel to the coil portions of the upper and lower coils and located between the upper and lower coils is designated as the XY plane, where one direction is referred to as the vertical direction and the other direction as the horizontal direction. The coil portion of the upper coil or the lower coil has an aspect ratio of 1 with respect to the dimensions along the vertical and horizontal dimensions.

14. The magnetic field generator of claim 8, wherein... The plane parallel to the coil portions of the upper and lower coils and located between the upper and lower coils is designated as the XY plane, where one direction is referred to as the vertical direction and the other direction as the horizontal direction. The coil portion of the upper coil or the lower coil has an aspect ratio that is not 1 with respect to the dimensions along the vertical and horizontal dimensions.

15. A magnetic field generator, comprising: The upper coil is made of a first conductive material and forms a ring circuit with a coil portion; The lower coil is made of a second conductive material and forms a ring circuit having coil portions arranged opposite to the coil portions of the upper coil at a predetermined distance. A substrate that supports the upper coil and the lower coil, and has a dielectric material located between the upper coil and the lower coil; as well as A grounding layer having a ground potential and comprising (i) a top grounding layer portion located on the top surface of the substrate, and (ii) a bottom grounding layer portion located on the bottom surface of the substrate, such that the upper coil and the lower coil are sandwiched between the top grounding layer portion and the bottom grounding layer portion, wherein High-frequency currents of opposite phase pass through the upper coil and the lower coil, respectively, and The length of each loop in the upper coil and the lower coil is matched to one wavelength of the high-frequency current.

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