JP2024076479A - Magnetic Sensor - Google Patents

Abstract

[Problem] To provide an improved magnetic sensor capable of detecting magnetic fields in the low frequency range with high sensitivity. [Solution] The magnetic sensor 1 comprises magnetic substance structures 10, 20 arranged in the X direction with a magnetic gap G1 between them, a magnetic sensing element R1 arranged on a magnetic path formed by the magnetic gap G1 and with the X direction as its sensitivity axis direction, magnetic substance structures 30, 40 magnetically connecting the magnetic substance structures 10 and 20 so as to bypass the magnetic gap G1, an excitation coil C1 wound around the magnetic substance structure 30, and an excitation coil C2 wound around the magnetic substance structure 40. According to this, by passing a current having a predetermined frequency through the excitation coils C1, C2, the detection signal output from the magnetic substance sensing element R1 can be modulated at the predetermined frequency, making it possible to detect magnetic fields in the low frequency range with high sensitivity. [Selected Figure] Figure 1

Description

This disclosure relates to a magnetic sensor, and in particular to a magnetic sensor capable of detecting magnetic fields in the low-frequency range with high sensitivity.

Currently, magnetic sensors using magneto-sensitive elements are used in a variety of fields, but to detect extremely weak magnetic fields, magnetic sensors with a high S/N ratio are required. One factor that reduces the S/N ratio of magnetic sensors is 1/f noise. Since 1/f noise becomes more pronounced the lower the frequency component of the magnetic field being measured, it is important to reduce 1/f noise in order to detect magnetic fields in the low-frequency range, for example, below 1 kHz, with high sensitivity.

The magnetic sensor described in Patent Document 1 is known as a magnetic sensor that reduces 1/f noise. The magnetic sensor described in Patent Document 1 reduces 1/f noise by modulating the operating point of the magnetic sensing element using a modulation means.

JP 2020-522696 A

However, the magnetic sensor described in Patent Document 1 had the problem that the noise of the magnetic sensing element itself was also modulated.

This disclosure describes an improved magnetic sensor that can detect magnetic fields in the low-frequency range with high sensitivity.

The magnetic sensor according to the present disclosure includes first and second magnetic structures arranged in a first direction via a magnetic gap, a magnetic sensing element arranged on a magnetic path formed by the magnetic gap and having a sensitivity axis direction in the first direction, third and fourth magnetic structures that magnetically connect the first magnetic structure and the second magnetic structure so as to bypass the magnetic gap, a first excitation coil wound around the third magnetic structure, and a second excitation coil wound around the fourth magnetic structure.

The present disclosure provides an improved magnetic sensor capable of detecting magnetic fields in the low-frequency range with high sensitivity.

FIG. 1 is a schematic perspective view showing the appearance of a magnetic sensor 1 according to a first embodiment of the present disclosure. FIG. 2 is a schematic exploded perspective view of the magnetic sensor 1. As shown in FIG. FIG. 3 is a schematic exploded perspective view showing the magnetic substance structures 10 and 20 and the sensor chip 100 separated from each other. FIG. 4 is a schematic perspective view for explaining the structure of the sensor chip 100. As shown in FIG. FIG. 5 is a schematic perspective view showing the sensor chip 100 with the magnetic layers 111 and 112 removed. FIG. 6 is an XZ cross-sectional view of a main part of the sensor chip 100. As shown in FIG. FIG. 7 is a schematic diagram for explaining a method of using the magnetic sensor 1. As shown in FIG. FIG. 8 is a graph for explaining the effect of the magnetic sensor 1. In FIG. FIG. 9 is a schematic perspective view showing the appearance of a magnetic sensor 2 according to the second embodiment of the present disclosure. FIG. 10 is a schematic exploded perspective view of the magnetic sensor 2. As shown in FIG. FIG. 11 is a schematic perspective view showing the appearance of a magnetic sensor 3 according to the third embodiment of the present disclosure.

Below, an embodiment of the technology disclosed herein will be described in detail with reference to the attached drawings.

Figure 1 is a schematic perspective view showing the appearance of a magnetic sensor 1 according to a first embodiment of the present disclosure. Also, Figure 2 is a schematic exploded perspective view of the magnetic sensor 1.

As shown in Figures 1 and 2, the magnetic sensor 1 according to the first embodiment includes a substrate 5, and a sensor chip 100 and magnetic structures 10, 20, 30, and 40 mounted on the substrate 5. The substrate 5 has an XZ plane as its main surface, and the sensor chip 100 and magnetic structures 10, 20, 30, and 40 are mounted on the main surface.

The magnetic substance structures 10, 20, 30, and 40 are all blocks made of a high magnetic permeability material such as ferrite. The magnetic substance structure 10 is made of a rod-shaped main body 11 with the X direction as its longitudinal direction, and a protrusion 12 provided at the end of the main body 11 in the -X direction. Similarly, the magnetic substance structure 20 is made of a rod-shaped main body 21 with the X direction as its longitudinal direction, and a protrusion 22 provided at the end of the main body 21 in the +X direction. The protrusion 12 and the protrusion 22 are not in contact with each other, and a magnetic gap G1 in the X direction is formed between them. In this way, the magnetic substance structures 10 and 20 are arranged in the X direction via the magnetic gap G1. The thickness of the protrusions 12 and 22 in the Z direction is thinner than the thickness of the main bodies 11 and 21 in the Z direction, and the sensor chip 100 is arranged so as to overlap the protrusions 12 and 22 in the Z direction.

The magnetic substance structure 30 has a winding core 31 around which the excitation coil C1 is wound, a connection part 32 located at the end of the winding core 31 in the +X direction and magnetically connecting the winding core 31 to the magnetic substance structure 10, and a connection part 33 located at the end of the winding core 31 in the -X direction and magnetically connecting the winding core 31 to the magnetic substance structure 20. Similarly, the magnetic substance structure 40 has a winding core 41 around which the excitation coil C2 is wound, a connection part 42 located at the end of the winding core 41 in the +X direction and magnetically connecting the winding core 41 to the magnetic substance structure 10, and a connection part 43 located at the end of the winding core 41 in the -X direction and magnetically connecting the winding core 41 to the magnetic substance structure 20. As a result, both of the magnetic substance structures 30 and 40 magnetically connect the magnetic substance structure 10 to the magnetic substance structure 20 so as to bypass the magnetic gap G1. The thickness in the Z direction and the height in the Y direction of the winding core parts 31 and 41 are smaller than the thickness in the Z direction and the height in the Y direction of the connection parts 32, 33, 42, and 43, which prevents interference between the excitation coils C1 and C2 and the magnetic structures 10 and 20 and the sensor chip 100, and also prevents interference between the excitation coils C1 and C2 and the substrate 5.

The magnetic substance structures 30 and 40 have the same shape. Therefore, the magnetic substance structures 30 and 40 are plane-symmetrical with respect to the XY plane passing through the centers of the magnetic substance structures 10 and 20 in the Z direction. The magnetic substance structures 10 and 20 may also have the same shape.

Figure 3 is a schematic exploded perspective view showing the magnetic structures 10, 20 and the sensor chip 100 separated.

As shown in FIG. 3, the element forming surface 105, which is the main surface of the sensor chip 100, constitutes an XY plane. In other words, the element forming surface 105 of the sensor chip 100 is perpendicular to the main surface of the substrate 5. Magnetic layers 111 and 112 are formed on the element forming surface 105. The magnetic layer 111 overlaps the protruding portion 12 of the magnetic substance structure 10 in the Z direction, and the magnetic layer 112 overlaps the protruding portion 22 of the magnetic substance structure 20 in the Z direction.

Figure 4 is a simplified perspective view illustrating the structure of the sensor chip 100.

As shown in FIG. 4, the magnetic sensing element R1, magnetic layers 111 and 112, and terminal electrodes T11 to T14 are formed on the element forming surface 105 of the sensor chip 100. The magnetic layers 111 and 112 are thin films made of NiFe-based materials such as permalloy, and the magnetic sensing element R1 is arranged on a magnetic path formed by the magnetic gap G2 made of the magnetic layers 111 and 112. The magnetic gap G2 is narrower than the magnetic gap G1, which reduces leakage magnetic flux, so that a larger magnetic field can be applied to the magnetic sensing element R1 compared to the case where the magnetic layers 111 and 112 are not provided. The magnetic layer 111 overlaps the protrusion 12 of the magnetic structure 10 in the Z direction, and the magnetic layer 112 overlaps the protrusion 22 of the magnetic structure 20 in the Z direction. As a result, the magnetic flux in the X direction flowing between the magnetic structures 10 and 20 is applied to the magnetic sensing element R1 via the magnetic layers 111 and 112.

Figure 5 is a simplified perspective view showing the sensor chip 100 with the magnetic layers 111 and 112 removed.

As shown in FIG. 5, the magnetic sensing element R1 extends in the Y direction on the element forming surface 105, one end of which is connected to the terminal electrode T11 via the wiring L1, and the other end of which is connected to the terminal electrode T12 via the wiring L2. The magnetic sensing element R1 is a magnetoresistance effect element whose electrical resistance changes depending on the direction of the magnetic flux. The fixed magnetization direction, which is the sensitivity axis direction of the magnetic sensing element R1, is the X direction. In the present invention, the magnetic sensing element R1 does not need to be a magnetoresistance effect element, but by using a magnetoresistance effect element as the magnetic sensing element R1, it becomes possible to detect a weak magnetic field with high sensitivity. A compensation coil 120 is also formed in the lower or upper layer of the element forming surface 105. One end of the compensation coil 120 is connected to the terminal electrode T13, and the other end is connected to the terminal electrode T14. The compensation coil 120 is used to perform so-called closed loop control by canceling out the magnetic field applied to the magnetic sensing element R1. In this embodiment, the sensor chip 100 is mounted upright so that the element forming surface 105, which is the main surface of the sensor chip 100, is perpendicular to the main surface of the substrate 5, thereby shortening the wiring distance between the terminal electrodes T11 to T14 and the substrate 5. This makes it possible to directly connect the land pattern provided on the substrate 5 to the terminal electrodes T11 to T14 using solder or the like.

Figure 6 is an XZ cross-sectional view of the main part of the sensor chip 100.

6, a magnetic sensing element R1 is formed on the element forming surface 105 of the sensor chip 100. The magnetic sensing element R1 is covered with an insulating layer 107, and magnetic layers 111 and 112 are formed on the surface of the insulating layer 107. The magnetic layers 111 and 112 are covered with an insulating layer 108. In addition, in a plan view (viewed from the Z direction), the magnetic sensing element R1 is located between the magnetic layers 111 and 112. As a result, the magnetic field passing through the magnetic gap G2 is applied to the magnetic sensing element R1. In other words, the magnetic sensing element R1 is located near the magnetic gap G2 formed by the magnetic layers 111 and 112, and is arranged on a magnetic path that can detect the magnetic field to be detected that passes through the magnetic gap G2. In this way, it is not necessary to arrange the magnetic sensing element R1 between the two magnetic layers 111 and 112, and it is sufficient that at least a part of the magnetic field passing through the magnetic gap G2 formed by the magnetic layers 111 and 112 is applied to the magnetic sensing element R1. The relationship between the width of the magnetic gap G2 and the width of the magnetic sensing element R1 is not particularly limited. In the example shown in FIG. 6, the width G2x of the magnetic gap G2 in the X direction is narrower than the width Rx of the magnetic sensing element R1 in the x direction, and as a result, the magnetic layers 111, 112 and the magnetic sensing element R1 overlap OV when viewed from the Z direction. In order to apply as much of the magnetic field passing through the magnetic gap G2 to the magnetic sensing element R1, it is desirable that the distance in the Z direction between the magnetic layers 111, 112 and the magnetic sensing element R1 at the overlap OV is as close as possible, and it is even more desirable that the distance in the Z direction between the magnetic layers 111, 112 and the magnetic sensing element R1 is closer than the width G2x of the magnetic gap G2 in the X direction. As a result, the magnetic sensing element R1 becomes the main magnetic path of the magnetic field passing through the magnetic gap G2.

Figure 7 is a schematic diagram for explaining how to use the magnetic sensor 1 according to this embodiment.

As shown in FIG. 7, when using the magnetic sensor 1 according to this embodiment, the excitation coils C1 and C2 are connected to a modulation circuit 50 to pass an AC current i having a predetermined frequency through the excitation coils C1 and C2. Here, the winding direction and current direction of the excitation coils C1 and C2 are set so that the direction A of the magnetic flux flowing through the magnetic structure 30 by the excitation coil C1 and the direction B of the magnetic flux flowing through the magnetic structure 40 by the excitation coil C2 are opposite to each other. The excitation coils C1 and C2 are connected in series, so that the amount of current flowing through the excitation coils C1 and C2 is the same. In addition, a variable resistor 51 is connected to the current path of the AC current i, and the amount of the AC current i can be adjusted by changing the resistance value of the variable resistor 51. Instead of the AC current i, a pulsed DC current may be intermittently passed.

When the magnetic structures 30, 40 are excited by passing an AC current i through the excitation coils C1, C2, the magnetic structures 30, 40 are magnetically saturated, and the magnetic permeability is significantly reduced. In other words, during the period when the magnetic structures 30, 40 are excited, the magnetic field component in the X direction to be detected passes through the magnetic structures 10, 20 without bypassing the magnetic structures 30, 40. Therefore, the magnetic field in the X direction passing through the magnetic gap G1 is applied to the magnetic sensing element R1. In addition, a feedback current corresponding to the detection signal obtained from the magnetic sensing element R1 flows through the compensation coil 120, and the magnetic field applied to the magnetic sensing element R1 is kept at zero by the cancellation magnetic field generated by this. Such closed-loop control makes it possible to obtain high detection accuracy.

In addition, since the direction A of the magnetic field generated by the magnetic structure 30 by the excitation coil C1 and the direction B of the magnetic field generated by the magnetic structure 40 by the excitation coil C2 are opposite to each other, the magnetic field generated by the excitation coils C1 and C2 circulates around the loop consisting of the magnetic structures 10, 20, 30, and 40. Therefore, the magnetic field generated by the excitation coils C1 and C2 is hardly applied to the magnetic sensing element R1. In particular, in this embodiment, since the magnetic structure 30 and the magnetic structure 40 are arranged symmetrically with respect to the XY plane, there is little leakage of the magnetic field circulating around the loop consisting of the magnetic structures 10, 20, 30, and 40, and it has almost no effect on the magnetic sensing element R1.

On the other hand, at the timing when the current flowing through the excitation coils C1, C2 becomes zero, the magnetic material structures 30, 40 are not excited, so the magnetic permeability of the magnetic material structures 30, 40 is maintained at a high level. As a result, the magnetic field component in the X direction to be detected does not pass through the magnetic material structures 10, 20 having the magnetic gap G1, but is bypassed by the magnetic material structures 30, 40. Therefore, the magnetic field in the X direction to be detected is no longer applied to the magnetic sensing element R1.

In this way, during the period when the excitation coils C1 and C2 are excited, the magnetic field component in the X direction to be detected is applied to the magnetic sensing element R1, and during the period when the excitation coils C1 and C2 are not excited, the magnetic field component in the X direction to be detected bypasses the magnetic structures 30 and 40. As a result, the detection signal obtained from the magnetic sensing element R1 is modulated by the frequency of the AC current i, and 1/f noise is significantly reduced.

In this way, the magnetic sensor 1 according to this embodiment includes a pair of magnetic structures 10, 20 that collect the weak magnetic field to be detected in the magnetic sensor element R1, and also includes magnetic structures 30, 40 that bypass the magnetic gap G1 formed by the magnetic structures 10, 20, and the excitation coils C1, C2 are wound around the magnetic structures 30, 40, respectively. This allows the detection signal obtained by the magnetic sensor element R1 to be modulated by passing an AC current i through the excitation coils C1, C2. As a result, even if the frequency of the weak magnetic field to be detected is low, it is possible to significantly reduce 1/f noise. Moreover, the magnetic field generated by the excitation coils C1, C2 circulates around the magnetic structures 10, 20, 30, 40 in a loop shape and is not applied to the magnetic sensor element R1, so the noise of the magnetic sensor element R1 itself is not modulated. Furthermore, since a magnetoresistance effect element is used as the magnetic sensor element R1, the magnetic detection efficiency per unit area can be increased compared to the case where a coil is used to detect the magnetic field.

Figure 8 is a graph for explaining the effect of the magnetic sensor 1 according to this embodiment, where the solid line shows the frequency characteristics of noise in the magnetic sensor 1 according to this embodiment, and the dashed line shows the frequency characteristics of noise in a conventional magnetic sensor that does not have a modulation means. As shown in Figure 8, it can be seen that the magnetic sensor 1 according to this embodiment significantly reduces 1/f noise, especially in the low frequency range, because the detection signal obtained by the magnetic sensing element R1 is modulated.

Figure 9 is a schematic perspective view showing the appearance of the magnetic sensor 2 according to the second embodiment of the present disclosure. Also, Figure 10 is a schematic exploded perspective view of the magnetic sensor 2.

As shown in Figures 9 and 10, the magnetic sensor 2 according to the second embodiment differs from the magnetic sensor 1 according to the first embodiment described above in that the magnetic structures 30, 40 are each composed of a combination of three magnetic structure pieces. Since the other basic configurations are the same as those of the magnetic sensor 1 according to the first embodiment, the same elements are given the same reference numerals and redundant explanations are omitted.

The magnetic body structure 30 includes a magnetic body structure piece P1 around which an excitation coil C1 is wound, a magnetic body structure piece P2 that magnetically connects the magnetic body structure piece P1 to the magnetic body structure 10, and a magnetic body structure piece P3 that magnetically connects the magnetic body structure piece P1 to the magnetic body structure 20. Similarly, the magnetic body structure 40 includes a magnetic body structure piece P4 around which an excitation coil C2 is wound, a magnetic body structure piece P5 that magnetically connects the magnetic body structure piece P4 to the magnetic body structure 10, and a magnetic body structure piece P5 that magnetically connects the magnetic body structure piece P4 to the magnetic body structure 20. The magnetic body structure pieces P2 and P3 have an L-shaped groove, and the magnetic body structure 30 is formed by fitting the magnetic body structure piece P1 around which an excitation coil C1 is wound into this groove. Similarly, magnetic structure pieces P5 and P6 have an L-shaped groove, and magnetic structure 40 is formed by fitting magnetic structure piece P4, around which excitation coil C2 is wound, into this groove.

In this way, constructing the magnetic structures 30, 40 by combining multiple magnetic structure pieces not only makes it easier to process and modify the design of the magnetic block made of ferrite, etc., but also makes it easier to wind the excitation coils C1, C2. Furthermore, if positioning portions such as grooves that can position the magnetic structure pieces P1, P4 are provided in the magnetic structure pieces P2, P3, P5, P6, it becomes easier to position the magnetic structure pieces P1 and P2, P3, and the magnetic structure pieces P4 and P5, P6.

Figure 11 is a schematic perspective view showing the appearance of a magnetic sensor 3 according to a third embodiment of the present disclosure.

As shown in FIG. 11, the magnetic sensor 3 according to the third embodiment differs from the magnetic sensor 1 according to the first embodiment described above in that a magnetic material structure 60 is used instead of the magnetic material structures 30 and 40. The other basic configuration is the same as that of the magnetic sensor 1 according to the first embodiment, so the same elements are given the same reference numerals and redundant explanations are omitted.

The magnetic substance structure 60 has a winding core 61 around which the excitation coil C1 is wound, a winding core 62 around which the excitation coil C2 is wound, a connection part 63 that magnetically connects the winding core parts 61 and 62 to the magnetic substance structure 10, and a connection part 64 that magnetically connects the winding core parts 61 and 62 to the magnetic substance structure 20. The winding core part 62 is sandwiched in the Y direction between the magnetic substance structures 10 and 20 and the winding core part 61.

As illustrated by the magnetic sensor 3 according to the third embodiment, in the present invention, it is not essential that the magnetic structure bypassing the magnetic gap G1 is made up of two blocks that are symmetrical to each other. In addition, the two winding cores 61 and 62 around which the excitation coils C1 and C2 are wound, respectively, may have one end connected to the magnetic structure 10 via a common connection part 63 and the other end connected to the magnetic structure 20 via a common connection part 64.

Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications are possible without departing from the spirit of the present disclosure, and it goes without saying that these modifications are also included within the scope of the present disclosure.

The technology disclosed herein includes, but is not limited to, the following configuration examples:

The magnetic sensor according to the present disclosure includes first and second magnetic structures arranged in a first direction via a magnetic gap, a magnetic sensing element arranged on a magnetic path formed by the magnetic gap and having a sensitivity axis in the first direction, third and fourth magnetic structures that magnetically connect the first magnetic structure and the second magnetic structure so as to bypass the magnetic gap, a first excitation coil wound around the third magnetic structure, and a second excitation coil wound around the fourth magnetic structure. With this, by passing a current having a predetermined frequency through the first and second excitation coils, the detection signal output from the magnetic sensing element can be modulated at a predetermined frequency, making it possible to detect magnetic fields in the low-frequency range with high sensitivity.

In the above magnetic sensor, the first and second excitation coils may be connected in series so that they generate magnetic fields in opposite directions. In this way, the magnetic fields generated by the first and second excitation coils circulate around the first to fourth magnetic structures, so that the magnetic fields generated by the first and second excitation coils are less likely to become noise for the magnetic sensing element.

The above magnetic sensor may further include a modulation circuit that causes a current having a predetermined frequency to flow through the first and second excitation coils. This makes it possible to cause a current having a predetermined frequency to flow through the first and second excitation coils.

In the above magnetic sensor, the third and fourth magnetic structures may each be a combination of multiple magnetic structure pieces. This makes it easier to fabricate the third and fourth magnetic structures and to wind the first and second excitation coils.

In the above magnetic sensor, the third magnetic structure may include a first magnetic structure piece around which a first excitation coil is wound, a second magnetic structure piece that magnetically connects the first magnetic structure piece to the first magnetic structure, and a third magnetic structure piece that magnetically connects the first magnetic structure piece to the second magnetic structure, and the fourth magnetic structure may include a fourth magnetic structure piece around which a second excitation coil is wound, a fifth magnetic structure piece that magnetically connects the fourth magnetic structure piece to the first magnetic structure, and a sixth magnetic structure piece that magnetically connects the fourth magnetic structure piece to the second magnetic structure. This makes it possible to simplify the shape of each magnetic structure piece.

In the above magnetic sensor, the second and third magnetic structure pieces may have a positioning portion capable of positioning the first magnetic structure piece, and the fifth and sixth magnetic structure pieces may have a positioning portion capable of positioning the fourth magnetic structure piece. This makes it easy to position the first magnetic structure piece and the second and third magnetic structure pieces, and to position the fourth magnetic structure piece and the fifth and sixth magnetic structure pieces.

1 to 3 magnetic sensor 5 substrate 10, 20, 30, 40 magnetic substance structure 11, 21 main body 12, 22 protrusion 31, 41 winding core 32, 33, 42, 43 connection 50 modulation circuit 51 variable resistor 60 magnetic substance structure 61, 62 winding core 63, 64 connection 100 sensor chip 105 element formation surface 107, 108 insulating layer 111, 112 magnetic substance layer 120 compensation coil A, B direction C1, C2 excitation coil G1, G2 magnetic gap L1, L2 wiring P1 to P6 magnetic substance structure piece R1 magnetic sensing element T11 to T14 terminal electrode i AC current

Claims (6)

first and second magnetic structures arranged in a first direction with a magnetic gap between them;
a magnetic sensing element disposed on a magnetic path formed by the magnetic gap and having a sensitivity axis direction aligned with the first direction;
third and fourth magnetic body structures magnetically connecting the first magnetic body structure and the second magnetic body structure so as to bypass the magnetic gap;
a first exciting coil wound around the third magnetic structure;
a second excitation coil wound around the fourth magnetic structure. The magnetic sensor according to claim 1, wherein the first excitation coil and the second excitation coil are connected in series so as to generate magnetic fields in opposite directions. The magnetic sensor according to claim 2, further comprising a modulation circuit that passes a current having a predetermined frequency through the first and second excitation coils. The magnetic sensor according to any one of claims 1 to 3, wherein the third and fourth magnetic structures each consist of a combination of multiple magnetic structure pieces. the third magnetic structure includes a first magnetic structure piece around which the first excitation coil is wound, a second magnetic structure piece that magnetically connects the first magnetic structure piece and the first magnetic structure, and a third magnetic structure piece that magnetically connects the first magnetic structure piece and the second magnetic structure,
The magnetic sensor of claim 4, wherein the fourth magnetic structure includes a fourth magnetic structure piece around which the second excitation coil is wound, a fifth magnetic structure piece that magnetically connects the fourth magnetic structure piece to the first magnetic structure, and a sixth magnetic structure piece that magnetically connects the fourth magnetic structure piece to the second magnetic structure. the second and third magnetic structure pieces each have a positioning portion capable of positioning the first magnetic structure piece,
The magnetic sensor according to claim 5 , wherein the fifth and sixth magnetic structure pieces have positioning portions capable of positioning the fourth magnetic structure piece.

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