WO2024147171A1

WO2024147171A1 - Magnetic sensor

Info

Publication number: WO2024147171A1
Application number: PCT/JP2023/000007
Authority: WO
Inventors: 崇人福井
Original assignee: Tdk株式会社
Filing date: 2023-01-04
Publication date: 2024-07-11

Abstract

[Problem] To provide an improved magnetic sensor capable of detecting a magnetic field of a low-frequency region with high sensitivity. [Solution] A magnetic sensor 1 comprises: a sensor chip 100; a magnetic body structure M1 that applies a magnetic field to be detected to the sensor chip 100; and a saturation coil C1 wound on the magnetic body structure M1. The magnetic body structure M1 includes a magnetic body part 10 made of a ceramic soft-magnetic material, and a magnetic body part 20 made of a metal soft-magnetic material. The saturation coil C1 is wound on the magnetic body part 20. Accordingly, by supplying the saturation coil C1 with AC current having a prescribed frequency, the magnetic field applied to the sensor chip 100 can be modulated on the basis of the frequency of the AC current. Thus, the magnetic field of a low-frequency region can be detected with high sensitivity.

Description

Magnetic Sensors

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 comprises a magnetoelectric transducer, a first magnetic structure that applies a magnetic field to be detected to the magnetoelectric transducer, and a first saturation coil wound around the first magnetic structure, the first magnetic structure including a first magnetic part made of a ceramic-based soft magnetic material and a second magnetic part made of a metal-based soft magnetic material and magnetically coupled to the first magnetic part, and the first saturation coil is wound around the second magnetic part.

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 an 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 of the magnetic substance structure M1. FIG. 4 is a schematic enlarged perspective view of a portion of the magnetic sensor 1. As shown in FIG. FIG. 5 is a schematic perspective view for explaining the structure of the sensor chip 100. As shown in FIG. FIG. 6 is a schematic perspective view showing the sensor chip 100 with the magnetic layers 111 and 112 removed. FIG. 7 is an XZ cross-sectional view of a main part of the sensor chip 100. As shown in FIG. FIG. 8 is a schematic diagram for explaining a method of using the magnetic sensor 1. As shown in FIG. FIG. 9 is a graph showing the BH characteristics of the ceramic soft magnetic material constituting the magnetic body parts 10 and 30 and the metal soft magnetic material constituting the magnetic body parts 20 and 40. As shown in FIG. FIG. 10 is a graph showing the relationship between the relative permeability of the magnetic body parts 20, 40 and the magnetic flux density of the magnetic flux applied to the magnetoresistance effect element R1.

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

FIG. 1 is a simplified perspective view showing the appearance of a magnetic sensor 1 according to one embodiment of the present disclosure. FIG. 2 is a simplified exploded perspective view of the magnetic sensor 1.

As shown in Figures 1 and 2, the magnetic sensor 1 according to this embodiment includes a substrate 5, and a sensor chip 100 and magnetic structures M1 and M2 mounted on the substrate 5. As described below, the sensor chip 100 has a magnetoelectric conversion element, and the magnetic structures M1 and M2 serve to apply the magnetic field to be detected in the X direction to the magnetoelectric conversion element. The substrate 5 has an XZ plane as its main surface, and the sensor chip 100 and magnetic structures M1 and M2 are mounted on the main surface.

Figure 3 is a schematic exploded perspective view of the magnetic structure M1.

As shown in FIG. 3, the magnetic structure M1 has magnetic parts 10, 30 made of a ceramic soft magnetic material such as ferrite, magnetic parts 20, 40 made of a metal soft magnetic material such as permalloy or amorphous magnetic alloy, and non-magnetic parts 21, 41 that support the magnetic parts 20, 40, respectively. The magnetic parts 10, 30 are block-shaped and are arranged in the X direction on the substrate 5. In contrast, the magnetic parts 20, 40 are flat or ribbon-shaped extending in the X direction, and are supported by the high-strength non-magnetic parts 21, 41 made of alumina titanium carbide (AlTiC) or the like. There are no particular limitations on the material that makes up the non-magnetic parts 21, 41, and a resin material may be used.

The magnetic body part 10 has a main body part 11 and a protruding part 12 protruding in the X direction from an end surface 11A constituting the YZ plane of the main body part 11. The main body part 11 has two grooves 13, 14 extending in the X direction. The grooves 13, 14 are arranged in the Z direction. Similarly, the magnetic body part 30 has two grooves 33, 34 extending in the X direction. The grooves 33, 34 are arranged in the Z direction. The magnetic body part 20 and the non-magnetic body part 21 supporting it are fixed to the magnetic body parts 10, 30 by being accommodated in the grooves 13, 33. As a result, one end of the magnetic body part 20 in the X direction is magnetically coupled to the magnetic body part 10, and the other end of the magnetic body part 20 in the X direction is magnetically coupled to the magnetic body part 30. Similarly, the magnetic body part 40 and the non-magnetic body part 41 supporting it are fixed to the magnetic body parts 10, 30 by being accommodated in the grooves 14, 34. As a result, one end of the magnetic body part 40 in the X direction is magnetically coupled to the magnetic body part 10, and the other end of the magnetic body part 40 in the X direction is magnetically coupled to the magnetic body part 30. As a result, the magnetic body parts 10, 20, 30, and 40 form a ring structure.

Here, the magnetic body parts 20, 40 are supported by the non-magnetic body parts 21, 41, respectively, because the metallic soft magnetic material constituting the magnetic body parts 20, 40 is flat or ribbon-shaped, and the magnetic body parts 20, 40 alone are insufficient in mechanical strength and workability. As shown in FIG. 3, the non-magnetic body part 21 has a support surface 21A constituting the XY plane, and the magnetic body part 20 is attached to this support surface 21A. The support surface 21A faces the magnetic body parts 10, 30, and thus, when the magnetic body part 20 and the non-magnetic body part 21 are accommodated in the grooves 13, 33, the magnetic body part 20 and the magnetic body parts 10, 30 come into contact with each other, and the two are magnetically coupled with low magnetic resistance. Similarly, the non-magnetic body part 41 has a support surface 41A constituting the XY plane, and the magnetic body part 40 is attached to this support surface 41A. The support surface 41A faces the magnetic parts 10 and 30, so that when the magnetic part 40 and the non-magnetic part 41 are housed in the grooves 14 and 34, the magnetic part 40 comes into contact with the magnetic parts 10 and 30, and the two are magnetically coupled with low magnetic resistance.

Then, a saturated coil C1 is wound around the magnetic body part 20 and the non-magnetic body part 21, and a saturated coil C2 is wound around the magnetic body part 40 and the non-magnetic body part 41. As shown in FIG. 3, a recess 21B is formed on the surface of the non-magnetic body part 21 opposite the support surface 21A, and the saturated coil C1 is wound around this recess 21B as the winding core. Similarly, a recess 41B is formed on the surface of the non-magnetic body part 41 opposite the support surface 41A, and the saturated coil C2 is wound around this recess 41B as the winding core.

The magnetic structure M2, like the magnetic parts 10 and 30, is made of a ceramic soft magnetic material such as ferrite, and has a bobbin-shaped main body 51 and a protruding part 52 protruding from the main body 51. A compensation coil C3 is wound around the bobbin-shaped main body 51. As described later, if a compensation coil is integrated in the sensor chip 100, the compensation coil C3 may be omitted. The protruding part 12 belonging to the magnetic structure M1 and the protruding part 52 belonging to the magnetic structure M2 are not in contact with each other, and a magnetic gap G1 in the X direction is formed between them. The thickness of the protruding parts 12 and 52 in the Z direction is thinner than the thickness of the main body parts 11 and 51 in the Z direction, and the sensor chip 100 is positioned so that it overlaps with the protruding parts 12 and 52 in the Z direction.

As shown in FIG. 2, the sensor chip 100 has side surfaces 101 and 102 that form a YZ plane and are located opposite each other, side surfaces 103 and 104 that form an XZ plane and are located opposite each other, and an element forming surface 105 and a back surface 106 that form an XY plane and are located opposite each other. The sensor chip 100 is mounted upright on the substrate 5 so that the side surface 103 faces the main surface of the substrate 5. Then, as shown in FIG. 4, the sensor chip 100 is mounted on the substrate 5 so that the side surface 101 of the sensor chip 100 faces the end surface 11A of the main body 11, and the side surface 102 of the sensor chip 100 faces the end surface 51A of the main body 51. Here, a gap in the X direction is formed between the side surface 101 of the sensor chip 100 and the end surface 11A of the main body 11. Similarly, a gap in the X direction is formed between the side surface 102 of the sensor chip 100 and the end surface 51A of the main body 51. By providing such a gap, the sensor chip 100 and the main body parts 11 and 51 do not interfere with each other in the X direction, making it possible to fine-tune the position of the sensor chip 100 in the X direction.

Magnetic layers 111 and 112 are formed on element forming surface 105, which is the main surface of sensor chip 100. The position of sensor chip 100 in the X direction on substrate 5 is adjusted so that magnetic layer 111 overlaps protruding portion 12 in the Z direction, and magnetic layer 112 overlaps protruding portion 52 in the Z direction.

Figure 5 is a simplified perspective view illustrating the structure of the sensor chip 100.

As shown in FIG. 5, the magnetoresistance effect element R1, magnetic layers 111 and 112, and terminal electrodes T11 to T14 are formed on the element formation 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 magnetoresistance effect element R1 is disposed on a magnetic path formed by a 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, allowing a larger magnetic field to be applied to the magnetoresistance effect 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 part 10 in the Z direction, and the magnetic layer 112 overlaps the protrusion 52 of the magnetic structure M2 in the Z direction. As a result, the magnetic flux in the X direction flowing between the magnetic structures M1 and M2 is applied to the magnetoresistance effect element R1 via the magnetic layers 111 and 112.

FIG. 6 is a simplified perspective view showing the sensor chip 100 with the magnetic layers 111 and 112 removed.

As shown in FIG. 6, the magnetoresistance effect 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 magnetoresistance effect 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 magnetoresistance effect element R1, is the X direction. In the present invention, the magnetoelectric conversion element does not need to be the magnetoresistance effect element R1, but by using the magnetoresistance effect element R1 as the magnetoelectric conversion element, it is 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 magnetoresistance effect 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 7 is an XZ cross-sectional view of the main part of the sensor chip 100.

As shown in FIG. 7, a magnetoresistance effect element R1 is formed on the element forming surface 105 of the sensor chip 100. The magnetoresistance effect 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 plan view (viewed from the Z direction), the magnetoresistance effect element R1 is located between the magnetic layers 111 and 112. This causes a magnetic field passing through the magnetic gap G2 to be applied to the magnetoresistance effect element R1. In other words, the magnetoresistance effect element R1 is located near the magnetic gap G2 formed by the magnetic layers 111 and 112, and is positioned on a magnetic path that can detect the magnetic field to be detected that passes through the magnetic gap G2. In this way, the magnetoresistance effect element R1 does not necessarily need to be disposed 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 magnetoresistance effect element R1. There is no particular limitation on the relationship between the width of the magnetic gap G2 and the width of the magnetoresistance effect element R1. In the example shown in FIG. 7, the width G2x of the magnetic gap G2 in the X direction is narrower than the width Rx of the magnetoresistance effect element R1 in the x direction, and thus the magnetic layers 111 and 112 and the magnetoresistance effect element R1 have an 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 magnetoresistance effect element R1, it is desirable that the distance in the Z direction between the magnetic layers 111 and 112 and the magnetoresistance effect element R1 in the overlap OV is as close as possible, and it is more desirable that the distance in the Z direction between the magnetic layers 111 and 112 and the magnetoresistance effect element R1 is closer than the width G2x of the magnetic gap G2 in the X direction. This makes the magnetoresistance effect element R1 the main magnetic path for the magnetic field passing through the magnetic gap G2.

FIG. 8 is a schematic diagram for explaining how to use the magnetic sensor 1 according to this embodiment.

As shown in FIG. 8, when using the magnetic sensor 1 according to this embodiment, the saturated coils C1 and C2 are connected to a modulation circuit 60, so that an AC current i having a predetermined frequency flows through the saturated coils C1 and C2. Here, the winding direction and current direction of the saturated coils C1 and C2 are set so that the direction A of the magnetic flux flowing through the magnetic body 20 by the saturated coil C1 and the direction B of the magnetic flux flowing through the magnetic body 40 by the saturated coil C2 are opposite to each other. The saturated coils C1 and C2 are connected in series, so that the amount of current flowing through the saturated coils C1 and C2 is the same. In addition, a variable resistor 61 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 61. Instead of the AC current i, a pulsed DC current may be intermittently passed.

When the magnetic body parts 20, 40 are excited by passing an AC current i through the saturation coils C1, C2, the magnetic body parts 20, 40 are magnetically saturated and the magnetic permeability is significantly reduced. In other words, during the period when the magnetic body parts 20, 40 are excited, the magnetic field component in the X direction applied to the magnetoresistance effect element R1 via the magnetic structure M1 is reduced.

Moreover, since the direction A of the magnetic field generated by the magnetic body 20 due to the saturated coil C1 and the direction B of the magnetic field generated by the magnetic body 40 due to the saturated coil C2 are opposite to each other, the magnetic field generated by the saturated coils C1 and C2 circulates around the loop consisting of the magnetic body parts 10, 20, 30, and 40. Therefore, the magnetic field generated by the saturated coils C1 and C2 is hardly applied to the magnetoresistance effect element R1.

On the other hand, at the timing when the current flowing through the saturation coils C1, C2 becomes zero, the magnetic body parts 20, 40 are not excited, so the magnetic permeability of the magnetic body parts 20, 40 is maintained at a high level. As a result, during the period when the magnetic body parts 20, 40 are not excited, the magnetic field component in the X direction is efficiently applied to the magnetoresistance effect element R1 via the magnetic structure M1. In addition, a feedback current corresponding to the detection signal obtained from the magnetoresistance effect element R1 flows through the compensation coil 120 or compensation coil C3, and the magnetic field applied to the magnetoresistance effect 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 this way, during the period when the saturation coils C1 and C2 are not excited, most of the X-direction magnetic field components to be detected are applied to the magnetoresistance effect element R1, and during the period when the saturation coils C1 and C2 are excited, the X-direction magnetic field components applied to the magnetoresistance effect element R1 are reduced. As a result, the detection signal obtained from the magnetoresistance effect element R1 is modulated by the frequency of the AC current i, and 1/f noise is significantly reduced.

Figure 9 is a graph showing the BH characteristics of the ceramic-based soft magnetic material that constitutes the magnetic parts 10 and 30 and the metal-based soft magnetic material that constitutes the magnetic parts 20 and 40, where (a) shows the case where the vertical axis is the absolute value, and (b) shows the case where the vertical axis is the normalized value.

As shown in Figure 9(a), it can be seen that the metallic soft magnetic material constituting the magnetic body parts 20, 40 has a higher magnetic permeability than the ceramic soft magnetic material constituting the magnetic body parts 10, 30. Moreover, as shown in Figure 9(b), it can be seen that the metallic soft magnetic material constituting the magnetic body parts 20, 40 has a steep BH characteristic and reaches magnetic saturation in a weaker magnetic field than the ceramic soft magnetic material constituting the magnetic body parts 10, 30.

In this embodiment, the saturation coils C1, C2 are wound around the magnetic parts 20, 40 made of a metal-based soft magnetic material, so that the magnetic parts 20, 40 can be saturated with less current, and more magnetic flux can be applied to the magnetoresistance effect element R1 during the period when the saturation coils C1, C2 are not excited. Furthermore, the magnetic parts 10, 30 made of a ceramic-based soft magnetic material that is easy to process and has excellent mechanical strength are used for the parts mounted on the substrate 5 and the parts that overlap with the sensor chip 100, so that the magnetic structure M1 can be easily manufactured and the mechanical strength of the entire magnetic structure M1 can be sufficiently ensured.

As described above, the magnetic sensor 1 according to this embodiment includes a pair of magnetic structures M1 and M2 that collect the weak magnetic field to be detected in the sensor chip 100, and saturation coils C1 and C2 that magnetically saturate the magnetic structure M1. This allows the detection signal obtained by the magnetoresistance effect element R1 to be modulated by passing an AC current i through the saturation coils C1 and 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 saturation coils C1 and C2 circulates around the loop-shaped magnetic structure M1 and is not applied to the magnetoresistance effect element R1, so the noise of the magnetoresistance effect element R1 itself is not modulated. Furthermore, since the magnetoresistance effect element R1 is used as a magnetoelectric conversion element, it is possible to detect magnetic fields with higher sensitivity.

Moreover, in this embodiment, the magnetic structure M1 is formed by combining magnetic parts 10, 30 made of a ceramic-based soft magnetic material and magnetic parts 20, 40 made of a metal-based soft magnetic material, and the magnetic parts 20, 40 are supported by non-magnetic parts 21, 41. In other words, the parts mounted on the substrate 5 (magnetic parts 10, 30) are made of a ceramic-based soft magnetic material, and the parts around which the saturation coils C1, C2 are wound (magnetic parts 20, 40) are made of a metal-based soft magnetic material. This makes it possible to ensure the workability and overall mechanical strength of the magnetic structure M1 while achieving sufficient modulation with a small excitation current.

Figure 10 is a graph showing the relationship between the relative permeability of the magnetic body parts 20, 40 and the magnetic flux density of the magnetic flux applied to the magnetoresistance effect element R1. As shown in Figure 10, when the relative permeability of the magnetic body parts 20, 40 decreases by passing a current through the saturation coils C1, C2, the magnetic flux density of the magnetic flux applied to the magnetoresistance effect element R1 decreases accordingly. The decrease in magnetic flux density is remarkable in the range of the relative permeability of the magnetic body parts 20, 40 from 100 to 10,000, while the decrease in magnetic flux density is slight even if the relative permeability of the magnetic body parts 20, 40 is reduced to less than 100. Considering this point, it can be said that the amount of current passed through the saturation coils C1, C2 is sufficient to reduce the relative permeability of the magnetic body parts 20, 40 to about 100, and there is little need to pass a current greater than that.

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 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 comprises a magnetoelectric conversion element, a first magnetic structure that applies a magnetic field to be detected to the magnetoelectric conversion element, and a first saturation coil wound around the first magnetic structure, the first magnetic structure including a first magnetic part made of a ceramic-based soft magnetic material and a second magnetic part made of a metal-based soft magnetic material and magnetically coupled to the first magnetic part, and the first saturation coil is wound around the second magnetic part. With this, by passing an alternating current having a predetermined frequency through the first saturation coil, the magnetic field applied to the magnetoelectric conversion element can be modulated by the frequency of the alternating current. This makes it possible to detect magnetic fields in the low frequency range with high sensitivity.

In the above magnetic sensor, the first magnetic structure may further include a non-magnetic part that supports the second magnetic part, and the first saturation coil may be wound around the second magnetic part and the non-magnetic part. This makes it possible to ensure sufficient mechanical strength for the entire first magnetic structure even if the mechanical strength of the second magnetic part is low.

The magnetic sensor further includes a second saturation coil wound around the first magnetic structure, and the first magnetic structure further includes a third magnetic part made of a ceramic-based soft magnetic material and a fourth magnetic part made of a metal-based soft magnetic material, and one end of the second and fourth magnetic parts is magnetically coupled to the first magnetic part and the other end of the second and fourth magnetic parts is magnetically coupled to the third magnetic part, so that the first to fourth magnetic parts have a ring-shaped structure, and the second saturation coil may be wound around the fourth magnetic part. In this way, the magnetic field generated by the first and second saturation coils circulates around the first to fourth magnetic parts having a ring-shaped structure, making it difficult for the magnetic field generated by the first and second saturation coils to be applied to the magnetoelectric conversion element.

In the above magnetic sensor, the magnetoelectric conversion element is provided on the main surface of a sensor chip having first and second magnetic layers, and the magnetoelectric conversion element is disposed on a magnetic path formed by a magnetic gap between the first and second magnetic layers, and the first magnetic portion of the first magnetic structure may overlap the first magnetic layer. This makes it possible to efficiently apply the magnetic field collected by the first magnetic structure to the magnetoelectric conversion element.

The above magnetic sensor may further include a second magnetic structure made of a ceramic soft magnetic material and overlapping the second magnetic layer, and a compensation coil wound around the second magnetic structure. This allows for so-called closed-loop control.

The above magnetic sensor further includes a substrate on which a sensor chip and a first magnetic structure are mounted, and the first magnetic part of the first magnetic structure has a main body to which the second magnetic part is fixed and a protrusion protruding from an end face of the main body, the protrusion covering the main surface of the sensor chip so as to overlap the first magnetic layer of the sensor chip, the end face of the main body covering a side surface of the sensor chip perpendicular to the main surface, and a predetermined gap may be formed between the end face of the main body and the side surface of the sensor chip. This prevents interference between the sensor chip and the first magnetic structure, making it possible to adjust the mounting position of the sensor chip with high precision.

In the above magnetic sensor, the magnetoelectric conversion element may be a magnetoresistance effect element. This makes it possible to provide a small, highly sensitive magnetic sensor.

1 Magnetic sensor 5 Substrate 10, 20, 30, 40 Magnetic body portion 11, 51 Main body portion 11A, 51A End surface 12, 52 Protrusion portion 13, 14, 33, 34 Groove 21, 41 Non-magnetic body portion 21A, 41A Support surface 21B, 41B Recess 60 Modulation circuit 61 Variable resistor 100 Sensor chip 101 to 104 Side surface 105 Element formation surface 106 Back surface 107, 108 Insulating layer 111, 112 Magnetic body layer 120 Compensation coil C1, C2 Saturation coil C3 Compensation coil G1, G2 Magnetic gap L1, L2 Wiring M1, M2 Magnetic body structure R1 Magnetoresistance effect element T11 to T14 Terminal electrode i AC current

Claims

A magnetoelectric conversion element;
a first magnetic structure that applies a magnetic field to be detected to the magnetoelectric conversion element;
a first saturating coil wound around the first magnetic structure;
the first magnetic structure includes a first magnetic body portion made of a ceramic-based soft magnetic material and a second magnetic body portion made of a metal-based soft magnetic material and magnetically coupled to the first magnetic body portion;
The first saturation coil is wound around the second magnetic material portion.
the first magnetic structure further includes a non-magnetic portion supporting the second magnetic portion,
The magnetic sensor according to claim 1 , wherein the first saturation coil is wound around the second magnetic material portion and the non-magnetic material portion.
a second saturating coil wound around the first magnetic structure;
The first magnetic structure further includes a third magnetic body portion made of a ceramic-based soft magnetic material and a fourth magnetic body portion made of a metal-based soft magnetic material,
one ends of the second and fourth magnetic body parts are magnetically coupled to the first magnetic body part, and the other ends of the second and fourth magnetic body parts are magnetically coupled to the third magnetic body part, so that the first to fourth magnetic body parts have annular structures;
The magnetic sensor according to claim 1 , wherein the second saturation coil is wound around the fourth magnetic portion.
the magnetoelectric conversion element is provided on a main surface of a sensor chip having first and second magnetic layers;
the magnetoelectric transducer is disposed on a magnetic path formed by a magnetic gap between the first magnetic layer and the second magnetic layer;
The magnetic sensor according to claim 1 , wherein the first magnetic material portion of the first magnetic material structure overlaps the first magnetic material layer.
a second magnetic structure made of a ceramic-based soft magnetic material and overlapping the second magnetic layer;
The magnetic sensor of claim 4 further comprising a compensation coil wound around the second magnetic material structure.
The sensor chip and the first magnetic structure are mounted on a substrate.
The first magnetic body portion of the first magnetic body structure has a main body portion to which the second magnetic body portion is fixed and a protrusion portion protruding from an end surface of the main body portion,
the protrusion covers the main surface of the sensor chip so as to overlap the first magnetic layer of the sensor chip;
the end surface of the body covers a side surface of the sensor chip that is perpendicular to the main surface,
The magnetic sensor according to claim 4 , wherein a predetermined gap is formed between the end surface of the main body and the side surface of the sensor chip.
The magnetic sensor according to any one of claims 1 to 5, wherein the magnetoelectric conversion element is a magnetoresistance effect element.