Magnetic sensor and magnetic field identification method
The magnetic sensor optimizes element placement and uses a magnetic focusing plate to efficiently identify three-dimensional magnetic field components, addressing size constraints and enhancing accuracy for miniaturized applications.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-09-27
- Publication Date
- 2026-04-08
AI Technical Summary
Existing magnetic sensors struggle to efficiently identify the three components (X, Y, and Z) of an incident magnetic field in a three-dimensional Cartesian coordinate system while maintaining a compact size, as they often require larger areas to accommodate magnetoelectric conversion elements and lack optimal layout designs.
A magnetic sensor design featuring a specific arrangement of magnetoelectric conversion elements with magnetosensitive axes rotated by 45 degrees and opposing directions, combined with a magnetic focusing plate, allows for a compact layout that minimizes the occupied area and enhances accuracy in identifying the three-dimensional magnetic field components.
The compact design enables precise identification of X, Y, and Z components with reduced size, suitable for integration into portable devices, improving miniaturization and functionality in multi-functional applications.
Smart Images
Figure 2026059910000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a magnetic sensor and a method for specifying a magnetic field.
Background Art
[0002] Patent Document 1 describes that "the sensor elements 211 and 212 detect a signal based on the X-axis component in addition to the signal based on the Z-axis component of the magnetic field, and the sensor elements 213 and 214 simultaneously detect a signal based on the Y-axis component in addition to the signal based on the Z-axis component of the magnetic field" (paragraph 0080). Patent Document 2 describes that "by sensing the three-dimensional position information of the magnet module using a plurality of Hall sensor groups, the angle formed by the first main body including the sensor unit and the second main body including the magnet module is measured" (paragraph 0012). [Prior Art Document] [Patent Document] [Patent Document 1] Patent No. 4939540 [Patent Document 2] Patent No. 6151301
Summary of the Invention
[0003] In a first embodiment of the present invention, a magnetic sensor is provided for identifying the three components X, Y, and Z of an incident magnetic field in a three-dimensional Cartesian coordinate system. The magnetic sensor comprises a pair of first magnetoelectric conversion elements located in the first and third quadrants and a pair of second magnetoelectric conversion elements located in the second and fourth quadrants, where four quadrants are defined from the X axis, the Y axis, and the intersection of the X axis and the Y axis, each of the pair of first magnetoelectric conversion elements has a magnetosensitive axis along a first axis obtained by rotating the X axis or the Y axis by 45 degrees, the pair of first magnetoelectric conversion elements are arranged such that the positive directions of their magnetosensitive axes are opposite to each other, and at least one of the pair of first magnetoelectric conversion elements is arranged along the first axis. The pair of first magnetoelectric elements has an electrode pair, each of which has a magnetosensitive axis along a second axis perpendicular to the first axis, and the pair of second magnetoelectric elements are arranged such that the positive directions of their magnetosensitive axes are opposite to each other. In the XY plane, the area of the virtual rectangle formed by connecting a pair of adjacent points of the pair of first magnetoelectric elements and a pair of adjacent points of the pair of second magnetoelectric elements is smaller than the area of each of the four magnetoelectric elements contained in the pair of first magnetoelectric elements and the pair of second magnetoelectric elements.
[0004] In the magnetic sensor described above, the distance between the centroid of one of the pair of first magnetoelectric conversion elements and the centroid of one of the pair of second magnetoelectric conversion elements in the XY plane may be shorter than the distance between the centroids of each of the pair of first magnetoelectric conversion elements.
[0005] In any of the above magnetic sensors, each of the four magnetoelectric conversion elements may have a rectangular outline with diagonals along the first and second axes in the XY plane. In any of the above magnetic sensors, in the XY plane, a virtual first quadrilateral formed by connecting the centroids of the four magnetoelectric conversion elements may be similar to a virtual second quadrilateral that circumscribes the four magnetoelectric conversion elements.
[0006] Any of the above magnetic sensors may include a magnetic focusing plate that is positioned in the XY plane such that its outer edge lies inside the second quadrilateral.
[0007] Any of the above magnetic sensors may include a magnetic focusing plate that is positioned in the XY plane such that it has an outer edge outside the first quadrilateral.
[0008] In any of the above magnetic sensors, the pair of first magnetoelectric conversion elements may be arranged to magnetoelectrically convert a magnetic field of +Hx+Hy and a magnetic field of -Hx-Hy. In any of the above magnetic sensors, the pair of second magnetoelectric conversion elements may be arranged to magnetoelectrically convert a magnetic field of -Hx+Hy and a magnetic field of +Hx-Hy.
[0009] A second embodiment of the present invention provides a magnetic sensor for identifying the three components X, Y, and Z of an incident magnetic field in a three-dimensional Cartesian coordinate system. The magnetic sensor comprises four magnetoelectric elements formed on a silicon substrate and a magnetic focusing plate positioned to overlap the four magnetoelectric elements, wherein at least one of the four magnetoelectric elements has an electrode pair positioned along a first axis rotated 45 degrees from the X or Y axis, and in the XY plane, the area of the portion of the magnetic focusing plate where the four magnetoelectric elements overlap is larger than the area of the portion of the magnetic focusing plate where the four magnetoelectric elements do not overlap, and the four magnetoelectric elements are positioned to detect Hx+Hy+Hz=A, -Hx+Hy+Hz=B, Hx-Hy+Hz=C, and -Hx-Hy+Hz=D, when the signal detected based on the X component of the incident magnetic field is defined as Hx, the signal detected based on the Y component is defined as Hy, and the signal detected based on the Z component is defined as Hz.
[0010] In the magnetic sensor described above, in the XY plane, each of the four magnetoelectric conversion elements has two pairs of electrodes, and the two pairs of electrodes are arranged such that the line connecting one pair of electrodes intersects the line connecting the other pair of electrodes, and the outer edge of the magnetic focusing plate may be positioned above or below one of the electrode pairs.
[0011] A third embodiment of the present invention provides a magnetic field determination method for determining the X, Y, and Z components of an incident magnetic field in a three-dimensional Cartesian coordinate system using four magnetoelectric elements. In the magnetic field determination method, at least one of the four magnetoelectric elements has an electrode pair arranged along a first axis rotated by 45 degrees from the X or Y axis, and magnetic focusing plates are arranged to overlap the four magnetoelectric elements, and in the XY plane, the area of the overlapping portion of the magnetic focusing plate of the four magnetoelectric elements is larger than the area of the non-overlapping portion of the magnetic focusing plate, and the magnetic field determination method determines the signal detected based on the X component of the incident magnetic field based on the Hx and Y components. When the signal detected is defined as Hy and the signal detected based on the Z component is defined as Hz, the system obtains four magnetic field values detected by the four magnetoelectric conversion elements: Hx+Hy+Hz=A, -Hx+Hy+Hz=B, Hx-Hy+Hz=C, and -Hx-Hy+Hz=D; and based on the four magnetic field values, it identifies Hx as Hx={(A+C)-(B+D)} / 4, Hy as Hy={(A+B)-(C+D)} / 4, and Hz as Hz=(A+B+C+D) / 4.
[0012] It should be noted that the above summary of the invention does not enumerate all of its features. Furthermore, subcombinations of these features may also constitute an invention. [Brief explanation of the drawing]
[0013] [Figure 1] This is a block diagram showing the schematic configuration of a magnetic field identification device 10 according to one embodiment. [Figure 2] This is a schematic plan view showing an example of the configuration of a magnetic sensor 100 according to one embodiment. [Figure 3] This is a plan view illustrating the arrangement of magnetoelectric conversion elements 101 and other components in a magnetic sensor 100 according to one embodiment. [Figure 4]This is a plan view illustrating the arrangement of magnetoelectric conversion elements 101 and other components in a magnetic sensor 100 according to one embodiment. [Figure 5] This is a plan view illustrating the arrangement of magnetoelectric conversion elements 101 and other components in a magnetic sensor 100 according to one embodiment. [Figure 6] This is a cross-sectional view illustrating the incident magnetic field incident on the cross-section along line LL' in Figure 2. [Modes for carrying out the invention]
[0014] The present invention will be described below through embodiments of the invention, but these embodiments are not intended to limit the invention as defined in the claims. Furthermore, not all combinations of features described in the embodiments are necessarily essential to the solution of the invention.
[0015] Figure 1 is a block diagram showing the schematic configuration of a magnetic field identification device 10 according to one embodiment. Figure 2 is a schematic plan view showing an example of the configuration of a magnetic sensor 100 according to one embodiment. Figure 3 is a plan view for explaining the arrangement of magnetoelectric conversion elements 101, etc., in the magnetic sensor 100 according to one embodiment.
[0016] The magnetic field identification device 10 is a device that identifies the three components X, Y, and Z of an incident magnetic field in a three-dimensional Cartesian coordinate system. The magnetic field identification device 10 comprises a magnetic sensor 100, a signal selection unit 200, an amplifier 300, an ADC 400, and a calculation processing unit 500. The magnetic field identification device 10 can be incorporated into, for example, a portable device.
[0017] The magnetic sensor 100 is a sensor for identifying the three components described above. The magnetic sensor 100 includes a plurality of magnetoelectric conversion elements 101, 102, 103, and 104 for detecting the incident magnetic field. The magnetic sensor 100 of this embodiment further includes a silicon substrate 110 and a magnetic focusing plate 120, as shown in Figure 2. The three-dimensional orthogonal coordinate system described above is determined, for example, according to the atomic arrangement direction of the silicon substrate 110, but is not limited thereto. When the direction perpendicular to the wafer surface of the silicon substrate 110 is defined as the Z axis, the X and Y directions may be arbitrarily determined as two orthogonal axes in a plane perpendicular to the Z axis.
[0018] As shown in Figure 2, the magnetic sensor 100 comprises a pair of magnetoelectric conversion elements 101 and 104 located in the first quadrant I and the third quadrant III, and a pair of magnetoelectric conversion elements 102 and 103 located in the second quadrant II and the fourth quadrant IV, when four quadrants I to IV are defined from the X axis, Y axis, and the intersection of the X and Y axes. The pair of magnetoelectric conversion elements 101 and 104 is an example of a pair of first magnetoelectric conversion elements, and the pair of magnetoelectric conversion elements 102 and 103 is an example of a pair of second magnetoelectric conversion elements. The four magnetoelectric conversion elements 101, etc. are formed on a silicon substrate 110. In the following description, the magnetoelectric conversion elements 101, etc. may be referred to as Hall elements. Similarly, in the plan views from Figure 2 onward, the four quadrants I to IV are shown, and redundant explanations are omitted.
[0019] Each of the pair of magnetoelectric elements 101 and 104 has a magnetosensitive axis along a first axis obtained by rotating the X-axis or Y-axis by 45 degrees (π / 4). The pair of magnetoelectric elements 101 and 104 are arranged so that the positive directions of their magnetosensitive axes are opposite. More specifically, with respect to the first axis obtained by rotating the X-axis by 45 degrees, as shown by the fine dashed line in Figure 3, magnetoelectric element 101 has a magnetosensitive axis 131 along the first axis, and magnetoelectric element 104 has a magnetosensitive axis 134 along the first axis. In Figure 3, the magnetosensitive axes 131 and 134 are shown by the coarse dashed arrows. The magnetosensitive axis 131 is the axis obtained by rotating the X-axis by 45 degrees, and the magnetosensitive axis 134 is the axis obtained by rotating the X-axis by 225 degrees. Furthermore, the magnetic axis 131 of the magnetoelectric conversion element 101, etc., is determined by the relative position of the magnetoelectric conversion element 101, etc., with respect to the magnetic focusing plate 120, which is shown by the dashed line in Figures 2 and 3, as will be described in more detail later.
[0020] At least one of the pair of magnetoelectric elements 101 and 104 has an electrode pair arranged along a first axis. More specifically, as shown in Figures 2 and 3, the magnetoelectric element 101 has a pair of electrodes 141-1 and 141-4 and a pair of electrodes 141-2 and 141-3, with the pair of electrodes 141-1 and 141-4 arranged along the first axis. The pair of electrodes 141-2 and 141-3 are arranged along an axis intersecting the first axis. In other words, in the XY plane, the magnetoelectric element 101 has two sets of electrode pairs, and the two sets of electrode pairs are arranged such that the line connecting one electrode pair to each other intersects the line connecting the other electrode pair to each other. For example, the pair of electrodes 141-2 and 141-3 may be arranged along the second axis, as described later, as shown in Figure 2. That is, the line connecting the pair of electrodes 141-1 and 141-4 to each other may be perpendicular to the line connecting the pair of electrodes 141-2 and 141-3 to each other. The contour of the electrode 141-1, etc. in the XY plane may be triangular, as illustrated in Figures 2 and 3, or it may not be triangular. The same applies to the electrodes of other magnetoelectric conversion elements 104, etc., and redundant explanations will be omitted.
[0021] Similarly, the magnetoelectric conversion element 104 has a pair of electrodes 144-1 and 144-4, and a pair of electrodes 144-2 and 144-3. The pair of electrodes 144-1 and 144-4 are arranged along the first axis. The pair of electrodes 144-2 and 144-3 are arranged along an axis intersecting the first axis. In other words, in the XY plane, the magnetoelectric conversion element 104 has two pairs of electrode pairs, and the two pairs of electrode pairs are arranged such that the line connecting one pair of electrodes to each other intersects the line connecting the other pair of electrodes to each other. As an example, the pair of electrodes 144-2 and 144-3 may be arranged along the second axis described later, as shown in FIG. 2, that is, the line connecting the pair of electrodes 144-1 and 144-4 to each other may be arranged to be orthogonal to the line connecting the pair of electrodes 144-2 and 144-3 to each other.
[0022] On the other hand, each of the pair of magnetoelectric conversion elements 102 and 103 has a magnetization axis along the second axis orthogonal to the first axis. The pair of magnetoelectric conversion elements 102 and 103 are arranged such that the positive directions of their magnetization axes are opposite to each other. More specifically, with respect to the second axis orthogonal to the first axis, which is shown by the thin broken line in FIG. 3, the magnetoelectric conversion element 102 has a magnetization axis 132 along the second axis, and the magnetoelectric conversion element 103 has a magnetization axis 133 along the second axis. In FIG. 3, the magnetization axes 132 and 133 are shown by the thick broken line arrows. The magnetization axis 132 is an axis obtained by rotating the X axis by 135 degrees, and the magnetization axis 133 is an axis obtained by rotating the X axis by 315 degrees.
[0023] At least one of the pair of magnetoelectric conversion elements 102 and 103 has an electrode pair arranged along the second axis. More specifically, as shown in FIGS. 2 and 3, the magnetoelectric conversion element 102 has a pair of electrodes 142-1 and 142-4, and a pair of electrodes 142-2 and 142-3, and the pair of electrodes 142-2 and 142-3 are arranged along the second axis. The pair of electrodes 142-1 and 142-4 are arranged along an axis intersecting the second axis. In other words, in the XY plane, the magnetoelectric conversion element 102 has two sets of electrode pairs, and the two sets of electrode pairs are arranged such that the line connecting one pair of electrodes to each other intersects the line connecting the other pair of electrodes to each other. As an example, the pair of electrodes 142-1 and 142-4 may be arranged along the first axis, that is, the line connecting the pair of electrodes 142-1 and 142-4 to each other may be arranged to be orthogonal to the line connecting the pair of electrodes 142-2 and 142-3 to each other.
[0024] Similarly, the magnetoelectric conversion element 103 has a pair of electrodes 143-1 and 143-4, and a pair of electrodes 143-2 and 143-3, and the pair of electrodes 143-2 and 143-3 are arranged along the second axis. The pair of electrodes 143-1 and 143-4 are arranged along an axis intersecting the second axis. In other words, in the XY plane, the magnetoelectric conversion element 103 has two sets of electrode pairs, and the two sets of electrode pairs are arranged such that the line connecting one pair of electrodes to each other intersects the line connecting the other pair of electrodes to each other. As an example, the pair of electrodes 143-1 and 143-4 may be arranged along the first axis, that is, the line connecting the pair of electrodes 143-1 and 143-4 to each other may be arranged to be orthogonal to the line connecting the pair of electrodes 143-2 and 143-3 to each other.
[0025] In Figure 3, the rectangle 150, shown by a rough, thick dashed line, is an example of a virtual rectangle formed in the XY plane by connecting a pair of adjacent points of a pair of magnetoelectric conversion elements 101 and 104 with a pair of adjacent points of a pair of magnetoelectric conversion elements 102 and 103. The rectangle 150 can also be described as a virtual rectangle formed by connecting the points closest to the origin of each magnetoelectric conversion element 101, 102, 104, and 103, in that order. In the magnetic sensor 100, the area of the rectangle 150 in the XY plane is smaller than the area of each of the four magnetoelectric conversion elements 101. In other words, the four magnetoelectric conversion elements 101 are formed close to each other on the silicon substrate 110 such that the area of the rectangle 150 is smaller than the area of each of the four magnetoelectric conversion elements 101.
[0026] As described above, the magnetic sensor 100 for identifying the three components X, Y, and Z of an incident magnetic field in a three-dimensional Cartesian coordinate system comprises a pair of magnetoelectric conversion elements 101 and 104 located in the first quadrant I and the third quadrant III, and a pair of magnetoelectric conversion elements 102 and 103 located in the second quadrant II and the fourth quadrant IV. Each pair of magnetoelectric conversion elements 101 and 104 has a magnetosensitive axis along a first axis obtained by rotating the X or Y axis by 45 degrees (π / 4), and is arranged so that the positive directions of their magnetosensitive axes are opposite. At least one of the pair of magnetoelectric conversion elements 101 and 104 has an electrode pair arranged along the first axis. On the other hand, each pair of magnetoelectric conversion elements 102 and 103 has a magnetosensitive axis along a second axis perpendicular to the first axis, and is arranged so that the positive directions of their magnetosensitive axes are opposite.
[0027] Here, as a comparative example of a magnetic sensor 100 having such a configuration, we assume a magnetic sensor comprising a pair of magnetoelectric conversion elements arranged on the X-axis such that the positive directions of their respective magnetic sensing axes are opposite along the X-axis, and another pair of magnetoelectric conversion elements arranged on the Y-axis such that the positive directions of their respective magnetic sensing axes are opposite along the Y-axis. In order for the magnetic sensor to identify the three XYZ components of the incident magnetic field, the pair of magnetoelectric conversion elements must be positioned so that their respective centroids are equidistant from the intersection of the two XY axes, i.e., the origin, in the XY plane, and the other pair of magnetoelectric conversion elements must also be positioned so that their respective centroids are equidistant from the origin in the XY plane.
[0028] In the comparative example magnetic sensor, when attempting to reduce the area occupied by a virtual rectangle on the XY plane circumscribing the four magnetoelectric conversion elements by arranging the four magnetoelectric conversion elements closer to the origin in the XY plane, the width occupied by a pair of magnetoelectric conversion elements arranged on one of the X or Y axes is approximately twice the element width. However, the width occupied by a pair of magnetoelectric conversion elements arranged on the other axis is approximately three times the element width because the pair of magnetoelectric conversion elements arranged on the other axis is interposed between them. Therefore, in the comparative example magnetic sensor, it is not possible to reduce the width occupied by the magnetoelectric conversion elements on at least one of the X or Y axes to three times the element width or less, and thus the aforementioned area cannot be sufficiently reduced.
[0029] In contrast, the magnetic sensor 100 of this embodiment, by having the above configuration, allows the pair of magnetoelectric conversion elements 101 and 104 to be placed close together along the first axis and the pair of magnetoelectric conversion elements 102 and 103 to be placed close together along the second axis without creating dead space near the origin. This minimizes the area occupied by the virtual rectangle on the XY plane that circumscribing the four magnetoelectric conversion elements 101, etc. Furthermore, the magnetic sensor 100 having the above configuration allows the pair of magnetoelectric conversion elements 101 and 104 to be placed spaced apart along the first axis and the pair of magnetoelectric conversion elements 102 and 103 to be placed spaced apart along the second axis, according to the design specifications. In other words, it increases the degree of freedom in the layout of the four magnetoelectric conversion elements.
[0030] Furthermore, as described above, the magnetic sensor 100 of this embodiment has a smaller area of rectangle 150 in the XY plane than each of the four magnetoelectric conversion elements 101, etc., so the occupied area can be significantly reduced compared to the magnetic sensor of the comparative example, and the magnetic sensor 100 can be miniaturized. The magnetic field identification device 10 equipped with the magnetic sensor 100 is incorporated into portable devices, etc., as described above, and the magnetic sensor 100 can meet the increasingly high demand for miniaturization of magnetic sensors that accompanies the demand for multi-functional and miniaturized portable devices. In addition, the magnetic sensor 100 can improve the accuracy of identifying the three XYZ components of the incident magnetic field by using the four magnetoelectric conversion elements 101, etc., which are arranged so closely together.
[0031] The following describes in more detail the four magnetoelectric conversion elements 101, etc., in the magnetic sensor 100 of this embodiment. As an example, the magnetoelectric conversion elements 101, etc., of this embodiment have a rectangular contour in the XY plane, as shown in Figures 2 and 3. More specifically, in the XY plane, each of the four magnetoelectric conversion elements 101, etc., has a rectangular contour with diagonals along the first and second axes described above. In addition, in the XY plane, the rectangular contour of the magnetoelectric conversion elements 101, etc., has a pair of opposing sides along the X axis and another pair of opposing sides along the Y axis. Note that the magnetoelectric conversion elements 101, etc., may have a contour other than a rectangle in the XY plane, for example, a cross-shaped contour where the part where the four electrodes 141-1, etc., are not arranged is concave.
[0032] Figure 4 is a plan view illustrating the arrangement of magnetoelectric conversion elements 101 and the like in a magnetic sensor 100 according to one embodiment. In Figure 4, the centroids G1, G3, and G4 of the magnetoelectric conversion elements 101, 103, and 104 in the XY plane are shown as black dots, the distance D1 between the centroid G1 of magnetoelectric conversion element 101 and the centroid G4 of magnetoelectric conversion element 104 is shown by an arrow, and the distance D2 between the centroid G1 of magnetoelectric conversion element 101 and the centroid G3 of magnetoelectric conversion element 103 is shown by an arrow.
[0033] According to one embodiment of the magnetic sensor 100, in the XY plane, the distance between the centroid of one of the pair of magnetoelectric conversion elements 101 and 104 and the centroid of one of the pair of magnetoelectric conversion elements 102 and 103 is shorter than the distance between the centroids of the pair of magnetoelectric conversion elements 101 and 104. More specifically, as shown in Figure 4, for example, the distance D2 between G1 and G3 is shorter than the distance D1 between G1 and G4.
[0034] Figure 5 is a plan view illustrating the arrangement of magnetoelectric conversion elements 101, etc., in a magnetic sensor 100 according to one embodiment. In Figure 5, the centroids G1, G2, G3, and G4 of the magnetoelectric conversion elements 101, 102, 103, and 104 in the XY plane are shown as black dots, a virtual first quadrilateral 161 formed by connecting the centroids G1, etc. of the four magnetoelectric conversion elements 101, etc., is shown as a thick solid line, and a virtual second quadrilateral 162 circumscribing the four magnetoelectric conversion elements 101, etc. is shown as a thick solid line.
[0035] According to one embodiment of the magnetic sensor 100, as shown in Figure 5, the first quadrilateral 161 and the second quadrilateral 162 described above are similar in the XY plane.
[0036] The magnetic focusing plate 120 of the magnetic sensor 100 of this embodiment is arranged to overlap the four magnetoelectric conversion elements 101, etc., as shown by the dashed line in Figures 2 to 5. Specifically, the magnetic focusing plate 120 is arranged to overlap the four magnetoelectric conversion elements 101, etc., on the positive Z-axis side, such that the outer edge of the magnetic focusing plate 120 is located on the positive Z-axis side of the four magnetoelectric conversion elements 101, etc.
[0037] More specifically, as shown in Figures 2 to 5, the magnetic focusing plate 120 is positioned in the XY plane such that its outer edge crosses above one of the two electrode pairs of each of the four magnetoelectric conversion elements 101, i.e., on the positive Z-axis side. Furthermore, as shown in Figure 5, the magnetic focusing plate 120 is positioned so that its outer edge lies inside the second quadrilateral 162 in the XY plane. Also, as shown in Figure 5, the magnetic focusing plate 120 is positioned so that its outer edge lies outside the first quadrilateral 161 in the XY plane.
[0038] In the magnetic sensor 100, the area of the overlapping portion of the four magnetoelectric conversion elements 101 on the magnetic focusing plate 120 in the XY plane is larger than the area of the non-overlapping portion of the magnetic focusing plate 120. With such a magnetic sensor 100, the occupied area can be significantly reduced compared to the magnetic sensor of the comparative example described above, and the magnetic sensor 100 can be miniaturized.
[0039] The magnetic focusing plate 120 is made of a ferromagnetic material, which has a high relative permeability. The contour of the magnetic focusing plate 120 in the XY plane may be circular, as shown in Figures 2 to 5, or it may be other than circular, as long as the tangent to the outer edge of the magnetic focusing plate 120 is substantially parallel to the first or second axis, that is, as long as the magnetic sensing axes 131 of the four magnetoelectric conversion elements 101 etc. are aligned with the first or second axis. The contour of the magnetic focusing plate 120 in the XY plane may be, for example, an annular shape or a polygon such as a rectangle, rhombus, octagon, or dodecagon. Furthermore, the thickness of the magnetic focusing plate 120 in the Z-axis direction may be arbitrary, and the thickness of the magnetic focusing plate 120 in the Z-axis direction may be uniform within the XY plane, or it may differ between the outer edge and the center.
[0040] Figure 6 is a cross-sectional view illustrating the incident magnetic field incident on the cross-section along line LL' in Figure 2. Each of the four magnetoelectric conversion elements 101, etc., having the arrangement described above, is able to detect signals based on the X-axis component and the Y-axis component of the incident magnetic field, in addition to the signal detected based on the Z-axis component, by the magnetic focusing plate 120, which is made of ferromagnetic material, distorting the magnetic field. More specifically, the four magnetoelectric conversion elements 101, etc., are sensitive to the magnetic component in the Z-axis direction (vertical direction), and as shown in Figures 2 to 5, they are arranged so as to be 90 degrees rotationally symmetric with respect to the origin, overlapping with the edge of the circular magnetic focusing plate 120 in a plan view. As shown by the multiple dashed curves in Figure 6, the magnetic flux in the X-axis direction and Y-axis direction (horizontal direction) is bent in the process of being absorbed by the magnetic focusing plate 120, and comes to have a vertical component. Therefore, the four magnetoelectric conversion elements 101, etc., detect the vertical magnetic flux whose path has been bent from the horizontal direction by the magnetic focusing plate 120. As a result, the magnetic sensor 100 can output a signal from four magnetoelectric conversion elements 101, etc., that is proportional to the sum of the vertical and horizontal magnetic field strengths. As shown in Figure 6, the four magnetoelectric conversion elements 101, etc., may be embedded in a silicon substrate 110 of any thickness, or they may be formed on the silicon substrate 110 by a semiconductor process. Also, as mentioned above, the three-dimensional orthogonal coordinate system is determined, for example, according to the atomic arrangement direction of the silicon substrate 110, but is not limited to this. When the direction perpendicular to the wafer surface of the silicon substrate 110 is taken as the Z axis, the X and Y directions may be arbitrarily determined as two orthogonal axes in a plane perpendicular to the Z axis.
[0041] More specifically, if we define the signal detected based on the X component of the incident magnetic field as Hx, the signal detected based on the Y component as Hy, and the signal detected based on the Z component as Hz, then the four magnetoelectric conversion elements 101 are arranged to detect Hx+Hy+Hz=A, -Hx+Hy+Hz=B, Hx-Hy+Hz=C, and -Hx-Hy+Hz=D. That is, as shown in Figure 1, magnetoelectric conversion element 101 outputs signal A=Hx+Hy+Hz, magnetoelectric conversion element 102 outputs signal B=-Hx+Hy+Hz, magnetoelectric conversion element 103 outputs signal C=Hx-Hy+Hz, and magnetoelectric conversion element 104 outputs signal D=-Hx-Hy+Hz. Since the magnetic sensor 100 is small in size, for example, sub-millimeters or less, it can be considered that a uniform magnetic field is incident on the entire magnetic sensor 100. If we exclude the perpendicular component of the incident magnetic field, we can also define that the pair of magnetoelectric conversion elements 101 and 104 are arranged to perform magnetoelectric conversion on magnetic fields of +Hx+Hy and -Hx-Hy, and the pair of magnetoelectric conversion elements 102 and 103 are arranged to perform magnetoelectric conversion on magnetic fields of -Hx+Hy and +Hx-Hy.
[0042] In the magnetic field identification device 10, the signal selection unit 200 selectively outputs each of the four signals A to D output from the magnetic sensor 100 to the amplifier 300 by sequentially switching between them in a time-division manner. Specifically, the signal selection unit 200 connects the output terminal of the magnetoelectric conversion element 101 to the input terminal of the amplifier 300 to output signal A to the amplifier 300, then connects the output terminal of the magnetoelectric conversion element 102 to the input terminal of the amplifier 300 to output signal B to the amplifier 300, then connects the output terminal of the magnetoelectric conversion element 103 to the input terminal of the amplifier 300 to output signal C to the amplifier 300, then connects the output terminal of the magnetoelectric conversion element 104 to the input terminal of the amplifier 300 to output signal D to the amplifier 300, and so on. The amplifier 300 amplifies the signal input from the signal selection unit 200 and outputs it to the ADC 400, which is an analog-to-digital conversion circuit. The ADC 400 converts the signal into digital data and outputs it to the arithmetic processing unit 500.
[0043] In this way, the arithmetic processing unit 500 obtains the values of four magnetic fields A through D. Based on these four magnetic field values, the arithmetic processing unit 500 determines Hx as Hx = {(A+C)-(B+D)} / 4, Hy as Hy = {(A+B)-(C+D)} / 4, and Hz as Hz = (A+B+C+D) / 4. Once the values of the signals Hx, Hy, and Hz are determined, the arithmetic processing unit 500 can determine the strengths of the X, Y, and Z components of the incident magnetic field corresponding to these values.
[0044] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications or improvements can be made to the above embodiments. It will be clear from the claims that such modified or improved forms may also be included in the technical scope of the present invention.
[0045] It should be noted that the execution order of operations, procedures, steps, and stages in the apparatus, systems, programs, and methods shown in the claims, specifications, and drawings is not explicitly stated as "before," "prior to," etc., and that these can be implemented in any order unless the output of a previous process is used in a later process. Even if the operation flow in the claims, specifications, and drawings is described using phrases such as "first," "next," etc. for convenience, it does not mean that it is essential to perform the operations in that order. [Other possible items] [Item 1] A magnetic sensor for determining the three components X, Y, and Z of an incident magnetic field in a three-dimensional Cartesian coordinate system, When four quadrants are defined by the X-axis, the Y-axis, and the intersection points of the X-axis and the Y-axis, the device comprises a pair of first magnetoelectric conversion elements located in the first and third quadrants, and a pair of second magnetoelectric conversion elements located in the second and fourth quadrants. Each of the pair of first magnetoelectric elements has a magnetosensitive axis along a first axis obtained by rotating the X-axis or Y-axis by 45 degrees, and the pair of first magnetoelectric elements are arranged such that the positive directions of their magnetosensitive axes are opposite to each other, and at least one of the pair of first magnetoelectric elements has a pair of electrodes arranged along the first axis. Each of the pair of second magnetoelectric conversion elements has a magnetosensitive axis along a second axis perpendicular to the first axis, and the pair of second magnetoelectric conversion elements are arranged such that the positive directions of their magnetosensitive axes are opposite to each other. Magnetic sensor. [Item 2] In the XY plane, the distance between the centroid of one of the pair of first magnetoelectric conversion elements and the centroid of one of the pair of second magnetoelectric conversion elements is shorter than the distance between the centroids of each of the pair of first magnetoelectric conversion elements. The magnetic sensor described in item 1. [Item 3] In the XY plane, each of the four magnetoelectric conversion elements included in the pair of first magnetoelectric conversion elements and the pair of second magnetoelectric conversion elements has a rectangular outline with diagonals along the first axis and the second axis. In the XY plane, the first virtual quadrilateral formed by connecting the centroids of the four magnetoelectric conversion elements is similar to the second virtual quadrilateral that the four magnetoelectric conversion elements circumscribe. The magnetic sensor described in item 1. [Item 4] The magnetic focusing plate is arranged in the XY plane such that its outer edge is inside the second quadrilateral. The magnetic sensor described in item 3. [Item 5] The magnetic focusing plate is arranged in the XY plane such that it has an outer green portion outside the first quadrilateral. The magnetic sensor described in item 3. [Item 6] The pair of first magnetoelectric conversion elements are arranged to perform magnetoelectric conversion on a magnetic field of +Hx+Hy and a magnetic field of -Hx-Hy. The pair of second magnetoelectric conversion elements are arranged to perform magnetoelectric conversion on a magnetic field of -Hx+Hy and a magnetic field of +Hx-Hy. A magnetic sensor as described in any one of items 1 through 5. [Item 7] A magnetic sensor for determining the three components X, Y, and Z of an incident magnetic field in a three-dimensional Cartesian coordinate system, Four magnetoelectric conversion elements formed on a silicon substrate, A magnetic focusing plate is positioned so as to overlap the four magnetoelectric conversion elements. Equipped with, At least one of the four magnetoelectric conversion elements has a pair of electrodes arranged along a first axis rotated by 45 degrees along the X or Y axis, When the signal detected based on the X component of the incident magnetic field is defined as Hx, the signal detected based on the Y component as Hy, and the signal detected based on the Z component as Hz, the four magnetoelectric conversion elements are arranged to detect Hx+Hy+Hz=A, -Hx+Hy+Hz=B, Hx-Hy+Hz=C, and -Hx-Hy+Hz=D. Magnetic sensor. [Item 8] In the XY plane, the area of the portion of the magnetic focusing plate where the four magnetoelectric conversion elements overlap is larger than the area of the portion of the magnetic focusing plate where the four magnetoelectric conversion elements do not overlap. The magnetic sensor described in item 7. [Item 9] In the XY plane, each of the four magnetoelectric conversion elements has two pairs of electrodes, and the two pairs of electrodes are arranged such that the line connecting one pair of electrodes intersects the line connecting the other pair of electrodes, and the outer edge of the magnetic focusing plate crosses above or below one of the electrode pairs. A magnetic sensor as described in item 7 or 8. [Item 10] A method for determining the X, Y, and Z components of an incident magnetic field in a three-dimensional Cartesian coordinate system using four magnetoelectric conversion elements, At least one of the four magnetoelectric conversion elements has a pair of electrodes arranged along a first axis rotated by 45 degrees along the X or Y axis, When the signal detected based on the X component of the incident magnetic field is defined as Hx, the signal detected based on the Y component as Hy, and the signal detected based on the Z component as Hz, the four magnetic field values detected by the four magnetoelectric conversion elements are obtained as follows: Hx+Hy+Hz=A, -Hx+Hy+Hz=B, Hx-Hy+Hz=C, and -Hx-Hy+Hz=D. Based on the four magnetic field values mentioned above, Hx is determined as Hx={(A+C)-(B+D)} / 4, Hy is determined as Hy={(A+B)-(C+D)} / 4, and Hz is determined as Hz=(A+B+C+D) / 4. A method for determining a magnetic field, comprising the following features. [Explanation of Symbols]
[0046] 10 Magnetic field identification device 100 Magnetic Sensors 101, 102, 103, 104 Magnetoelectric conversion elements 110 Silicon substrate 120 Magnetic Focusing Plate 131, 132, 133, 134 Magnetically sensitive axis 141-1, 141-2, 141-3, 141-4, 142-1, 142-2, 142-3, 142-4, 143-1, 143-2, 143-3, 143-4, 144-1, 144-2, 144-3, 144-4 Electrode 150 rectangle 161 1st quadrilateral 162 2nd quadrilateral 200 Signal Selection Section 300 Amplifier 400 ADC 500 Arithmetic Processing Unit D1, D2 distance G1, G2, G3, G4 Center of gravity LL′ line
Claims
1. A magnetic sensor for identifying the three components X, Y, and Z of an incident magnetic field in a three-dimensional Cartesian coordinate system, When four quadrants are defined from the X-axis, the Y-axis, and the intersection of the X-axis and the Y-axis, the device comprises a pair of first magnetoelectric conversion elements located in the first and third quadrants, and a pair of second magnetoelectric conversion elements located in the second and fourth quadrants. Each of the pair of first magnetoelectric elements has a magnetosensitive axis along a first axis obtained by rotating the X-axis or Y-axis by 45 degrees, and the pair of first magnetoelectric elements are arranged such that the positive directions of their magnetosensitive axes are opposite to each other, and at least one of the pair of first magnetoelectric elements has a pair of electrodes arranged along the first axis. Each of the pair of second magnetoelectric conversion elements has a magnetosensitive axis along a second axis perpendicular to the first axis, and the pair of second magnetoelectric conversion elements are arranged such that the positive directions of their magnetosensitive axes are opposite to each other. In the XY plane, the area of the virtual rectangle formed by connecting a pair of adjacent points of the pair of first magnetoelectric conversion elements and a pair of adjacent points of the pair of second magnetoelectric conversion elements is smaller than the area of each of the four magnetoelectric conversion elements included in the pair of first magnetoelectric conversion elements and the pair of second magnetoelectric conversion elements. Magnetic sensor.
2. In the XY plane, the distance between the centroid of one of the pair of first magnetoelectric conversion elements and the centroid of one of the pair of second magnetoelectric conversion elements is shorter than the distance between the centroids of each of the pair of first magnetoelectric conversion elements. The magnetic sensor according to claim 1.
3. In the XY plane, each of the four magnetoelectric conversion elements has a rectangular outline with diagonals along the first axis and the second axis. In the XY plane, a virtual first quadrilateral formed by connecting the centroids of the four magnetoelectric conversion elements is similar to a virtual second quadrilateral that circumscribes the four magnetoelectric conversion elements. The magnetic sensor according to claim 1.
4. The magnetic focusing plate is arranged in the XY plane such that its outer edge is inside the second quadrilateral. The magnetic sensor according to claim 3.
5. The magnetic focusing plate is arranged in the XY plane such that it has an outer green portion outside the first quadrilateral. The magnetic sensor according to claim 3.
6. The pair of first magnetoelectric conversion elements are arranged to perform magnetoelectric conversion on a magnetic field of +Hx+Hy and a magnetic field of -Hx-Hy. The pair of second magnetoelectric conversion elements are arranged to perform magnetoelectric conversion on a magnetic field of -Hx + Hy and a magnetic field of +Hx - Hy. A magnetic sensor according to any one of claims 1 to 5.
7. A magnetic sensor for identifying the three components X, Y, and Z of an incident magnetic field in a three-dimensional Cartesian coordinate system, Four magnetoelectric conversion elements formed on a silicon substrate, A magnetic focusing plate is arranged so as to overlap the four magnetoelectric conversion elements. Equipped with, At least one of the four magnetoelectric conversion elements has a pair of electrodes arranged along a first axis rotated by 45 degrees along the X or Y axis, In the XY plane, the area of the portion of the magnetic focusing plate where the four magnetoelectric conversion elements overlap is larger than the area of the portion of the magnetic focusing plate where the four magnetoelectric conversion elements do not overlap. When the signal detected based on the X component of the incident magnetic field is defined as Hx, the signal detected based on the Y component as Hy, and the signal detected based on the Z component as Hz, the four magnetoelectric conversion elements are arranged to detect Hx + Hy + Hz = A, -Hx + Hy + Hz = B, Hx - Hy + Hz = C, and -Hx - Hy + Hz = D. Magnetic sensor.
8. In the XY plane, each of the four magnetoelectric conversion elements has two pairs of electrodes, and the two pairs of electrodes are arranged such that the line connecting one pair of electrodes intersects the line connecting the other pair of electrodes, and the outer edge of the magnetic focusing plate crosses above or below one of the electrode pairs. The magnetic sensor according to claim 7.
9. A method for determining the X, Y, and Z components of an incident magnetic field in a three-dimensional Cartesian coordinate system using four magnetoelectric conversion elements, At least one of the four magnetoelectric conversion elements has a pair of electrodes arranged along a first axis rotated by 45 degrees along the X or Y axis, The four magnetoelectric conversion elements are arranged so that magnetic focusing plates overlap them. In the XY plane, the area of the portion of the magnetic focusing plate where the four magnetoelectric conversion elements overlap is larger than the area of the portion of the magnetic focusing plate where the four magnetoelectric conversion elements do not overlap. When the signal detected based on the X component of the incident magnetic field is defined as Hx, the signal detected based on the Y component as Hy, and the signal detected based on the Z component as Hz, the four magnetic field values detected by the four magnetoelectric conversion elements are obtained as follows: Hx + Hy + Hz = A, -Hx + Hy + Hz = B, Hx - Hy + Hz = C, and -Hx - Hy + Hz = D. Based on the four magnetic field values mentioned above, Hx is specified as Hx = {(A + C) - (B + D)} / 4, Hy is specified as Hy = {(A + B) - (C + D)} / 4, and Hz is specified as Hz = (A + B + C + D) / 4. A method for determining a magnetic field, comprising the following features.