magnetic sensor

Abstract

The present invention relates to a magnetic sensor. The object of the present invention is to improve the sensitivity of a magnetic sensor using a sensing element that senses a magnetic field by a magnetoimpedance effect. The solution of the present invention is that a magnetic sensor (200) is provided with: a sensing element (10) that senses a magnetic field by a magnetoimpedance effect; and a concentrating member (20) that is provided opposite to the sensing element (10), the concentrating member (20) being composed of a soft magnetic body and concentrating magnetic lines of force from the outside to the sensing element (10).

Description

Technical Field

[0001] This invention relates to magnetic sensors. Background Technology

[0002] As described in the prior art, there exists a magnetoresistive effect element comprising: a thin-film magnet formed on a non-magnetic substrate and formed of a hard magnetic film; an insulating layer covering the upper part of the aforementioned thin-film magnet; and a magnetically sensing portion formed on the aforementioned insulating layer, endowed with uniaxial anisotropy, and formed of one or more rectangular soft magnetic films (see Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2008-249406 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] For magnetic sensors that use sensing elements that sense magnetic fields through the magnetoresistance effect, high sensitivity to changes in the magnetic field is required.

[0008] The purpose of this invention is to improve the sensitivity of magnetic sensors that use sensing elements that sense magnetic fields through the magnetoresistance effect.

[0009] Methods for solving problems

[0010] The magnetic sensor employing the present invention comprises: a sensing element that senses a magnetic field through the magnetoresistance effect; and a clustering member disposed opposite to the sensing element, the clustering member being made of a soft magnetic material and causing magnetic field lines from the outside to be clustered onto the sensing element.

[0011] Such a magnetic sensor is characterized in that, for the clustering member, in the direction of intersection with the direction of the external magnetic field lines, the width of the side where the magnetic field lines enter from the outside is greater than the width of the side opposite to the sensing element.

[0012] Furthermore, the feature is that the clustering member has: a facing portion opposite to the sensing element; and a wide portion, which is provided on the side where the magnetic field lines enter from the outside, and the width in the direction of intersecting the direction of the external magnetic field lines is larger than that of the facing portion.

[0013] Alternatively, the feature may be that the clustering member comprises: a facing portion opposite to the sensing element; a wide portion disposed on the side where magnetic field lines enter from the outside, and the width in the direction intersecting the direction of the external magnetic field lines is greater than that of the facing portion; and an extension portion extending from the end of the wide portion toward the sensing element side.

[0014] Such a magnetic sensor is characterized by having a bias magnetic field applying member, which is arranged in a manner that contacts or approaches the gathering member, and applies a bias magnetic field to the sensing element through the gathering member.

[0015] In addition, the magnetic sensor of the present invention is characterized by having a diverging member disposed opposite to the sensing element, the diverging member being made of a soft magnet and causing the magnetic field lines passing through the sensing element to diverge outward.

[0016] Such a magnetic sensor is characterized in that, for the diverging component, in the direction where it intersects with the direction of the external magnetic field lines, the width of the side of the magnetic field lines radiating outward is greater than the width of the side opposite to the sensing element.

[0017] Furthermore, the feature is that the diverging member has: a facing portion opposite to the sensing element; and a wide portion, which is provided on the side where the magnetic field lines radiate outward, and the width in the direction intersecting the direction of the external magnetic field lines is greater than that of the facing portion.

[0018] Alternatively, the feature may be that the diverging member comprises: a facing portion opposite to the sensing element; a wide portion disposed on the side where the magnetic field lines radiate outward, and the width in the direction intersecting the direction of the external magnetic field lines is greater than that of the facing portion; and an extension portion extending from the end of the wide portion toward the sensing element side.

[0019] Such a magnetic sensor is characterized by having a bias magnetic field applying member, which is arranged in a manner that contacts or approaches a diverging member, and applies a bias magnetic field to the sensing element through the diverging member.

[0020] In addition, its feature is that the sensing element has a substrate and a sensing circuit, and the clustering member and the diverging member are disposed on the outside of the substrate.

[0021] The effects of the invention

[0022] According to the present invention, the sensitivity of a magnetic sensor using a sensing element that senses a magnetic field through the magnetoresistance effect can be improved. Attached Figure Description

[0023] [ Figure 1 [This is a diagram illustrating the magnetic sensor applied according to the first embodiment.]

[0024] [ Figure 2 [This is a diagram illustrating other magnetic sensors that utilize the first embodiment.]

[0025] [ Figure 3The figure illustrates an example of a sensing element. (a) is a top view, and (b) is a cross-sectional view along line IIIB-IIIB of (a).

[0026] [ Figure 4 This diagram illustrates the relationship between the magnetic field applied along the long side of the sensing part of the sensing element and the impedance of the sensing element.

[0027] [ Figure 5 [This is a diagram illustrating the relationship between impedance and magnetic field in the magnetic sensor using the first embodiment.]

[0028] [ Figure 6 [A graph showing the sensitivity and anisotropic magnetic field of the magnetic sensor applied in the first embodiment.]

[0029] [ Figure 7 [Figure 1] illustrates a modified example of the magnetic sensor according to the first embodiment. (a) is a magnetic sensor having a trapezoidal planar member and a diverging member, and (b) is a magnetic sensor having a Y-shaped planar member and a diverging member.

[0030] [ Figure 8 [A diagram showing the application of the magnetic sensor of the second embodiment.]

[0031] [ Figure 9 [Figure showing the detection sensitivity of the magnetic sensor applied in the second embodiment.]

[0032] [ Figure 10 [Figures illustrating the relationship between the method of applying the bias magnetic field and noise. (a) A magnetic sensor with a "T-shaped" clustering and diverging member, and using a permanent magnet to apply the bias magnetic field; (b) A magnetic sensor using a bonded magnet to apply the bias magnetic field.]

[0033] [ Figure 11 [Figure showing the noise in a magnetic sensor with a "T-shaped" clustering and diverging component and a bias magnetic field applied by a permanent magnet. (a) shows the time-varying voltage of the sensing element, and (b) shows the FFT data obtained by performing a Fast Fourier Transform (FFT) on the time-varying voltage.]

[0034] [ Figure 12 The figure illustrates the noise in a magnetic sensor that uses a bonded magnet to apply a bias magnetic field. (a) shows the time-varying voltage of the sensing element 10, and (b) shows the FFT data obtained by performing a Fast Fourier Transform (FFT) on the time-varying voltage.

[0035] [ Figure 13[Figure showing the application of another magnetic sensor 310 of the second embodiment.]

[0036] Explanation of reference numerals in the attached figures

[0037] 10… Sensing element, 11… Substrate, 12… Sensing circuit, 20, 21, 22, 23… Bundling member, 20a, 21a, 30a, 31a… Opposing part, 20b, 21b, 30b, 31b… Wide part, 21c, 21d, 31c, 31d… Extension part, 30, 31, 32, 33… Diverging member, 40… Permanent magnet, 50, 50a, 50b… Bonded magnet, 100, 200, 210, 220, 230, 300, 310, 400… Magnetic sensor, 121… Sensing part, 122… Connecting part, 123, 123a, 123b… Terminal part, H… Magnetic field, Hb… Bias magnetic field, Hk… Anisotropic magnetic field, Z… Impedance Detailed Implementation

[0038] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0039] [First Implementation]

[0040] (Magnetic sensors 200, 210)

[0041] Figure 1 This diagram illustrates the application of the magnetic sensor 200 according to the first embodiment. Figure 1 As shown, the horizontal direction of the attached drawing is taken as the x-direction, the upward direction as the y-direction, and the surface direction as the z-direction. It should be noted that... Figure 1 In the diagram, magnetic field lines are indicated by arrows.

[0042] The magnetic sensor 200 includes: a sensing element 10; a focusing member 20 that focuses magnetic field lines from external space onto the sensing element 10; and a diverging member 30 that diverges the magnetic field lines that have passed through the sensing element 10. Furthermore, the focusing member 20, the sensing element 10, and the diverging member 30 are arranged in this order along the x-direction. Here, the magnetic sensor 200 refers to... Figure 1 The portion enclosed by a dashed line is shown; the area outside of it is referred to as the outer space or the exterior. The same applies in other cases.

[0043] The sensing element 10 senses the magnetic field or changes in the magnetic field in the x direction through the magnetoresistance effect.

[0044] The clustering member 20 has a facing portion 20a opposite to the sensing element 10 and a wide portion 20b whose width in the y-direction is larger than that of the facing portion 20a. That is, the clustering member 20 is T-shaped in planar shape, with the facing portion 20a as the longitudinal line and the wide portion 20b as the transverse line. Moreover, the clustering member 20 has a certain thickness in the z-direction.

[0045] In the clustering member 20, the width W (in the y-direction) of the portion of the opposing part 20a opposite to the sensing element 10 20a For example, 4.5mm, the length L in the x-direction. 20a For example, the width W in the y-direction of the wide section 20b is 6mm. 20b For example, 16mm, the length L in the x direction 20b For example, it is 2mm. Furthermore, the distance L between the opposing portion 20a and the sensing element 10... 20ag For example, 2mm. It should be noted that these are just examples; other values ​​are also possible.

[0046] The diverging member 30 has a facing portion 30a opposite to the sensing element 10, and a wide portion 30b whose width in the y-direction is larger than that of the facing portion 30a. That is, the diverging member 30 has the same planar shape as the focusing member 20, and its planar shape is T-shaped. Moreover, the diverging member 30 has a certain thickness in the z-direction.

[0047] In the diverging member 30, the width W (in the y-direction) of the portion of the opposing part 30a opposite to the sensing element 10 30a For example, 4.5mm, the length L in the x-direction. 30a For example, the width W in the y-direction of the 30b wide section is 6mm. 30b For example, 16mm, the length L in the x direction 30b For example, it is 2mm. Furthermore, the distance L between the opposing portion 30a and the sensing element 10... 30ag For example, 2mm. It should be noted that these are just examples; other values ​​are also possible.

[0048] Incidentally, the magnetic sensor 200 has, in the x-direction, a wide portion 20b of the focusing member 20, a corresponding portion 20a, a sensing element 10, and a corresponding portion 30a and a wide portion 30b of the diverging member 30, arranged sequentially. Furthermore, the focusing member 20 and the diverging member 30 have the same T-shaped planar shape and are arranged symmetrically to sandwich the sensing element 10 in the x-direction. Hereinafter, the magnetic sensor 200 is described as having a "T-shaped" focusing member 20 and a diverging member 30.

[0049] It should be noted that, Figure 1In the shown clustering member 20, the opposing portion 20a is provided at the center of the wide portion 20b in the y-direction. However, the opposing portion 20a may not be provided at the center of the wide portion 20b, but may be provided at an end in the y-direction or an end in the -y-direction of the wide portion 20b. That is, the planar shape of the clustering member 20 may also be L-shaped ("L-shaped"). The same applies to the diverging member 30.

[0050] The clustering member 20 and the diverging member 30 are made of soft magnetic materials. Soft magnetic materials are materials with low coercivity, meaning they are easily magnetized by a magnetic field, but quickly return to an unmagnetized or poorly magnetized state when the magnetic field is removed. Here, the clustering member 20 and the diverging member 30 are, for example, made of ferrite. Examples of such ferrites include those made of MnZn with an initial permeability of 2500 ± 25% and a saturation magnetic flux density Bs of 420 mT. Furthermore, the opposing portion 20a and the wide portion 20b of the clustering member 20 are integrally formed, and the opposing portion 30a and the wide portion 30b of the diverging member 30 are also integrally formed.

[0051] like Figure 1 As shown, magnetic field lines from external space enter the wide portion 20b of the gathering member 20 from the left side (-x direction side) of the attached drawing. As they travel from the wide portion 20b towards the opposite portion 20a, they are gathered and emitted from the opposite portion 20a. Then, the magnetic field lines passing through the sensing element 10 enter the opposite portion 30a of the diverging member 30. Then, the magnetic field lines diverge as they travel from the opposite portion 30a towards the wide portion 30b, emitting from the wide portion 30b towards external space. That is, the magnetic field lines from external space are gathered by the gathering member 20, increasing the magnetic flux density (magnetic field line density) and allowing them to pass through the sensing element 10. It should be noted that... Figure 1 In this context, the magnetic field of external space (referred to as the external magnetic field) is denoted as magnetic field H.

[0052] Furthermore, the diverging member 30 and the converging member 20 have the same planar shape and are symmetrically arranged, sandwiching the sensing element 10 in the x-direction. The diverging member 30 is provided to allow the magnetic field lines, which have been converging in the converging member 20, to pass through the sensing element 10 in a converging state. That is, by providing the diverging member 30, the magnetic field lines can easily pass through the sensing element 10 in parallel. As a result, the magnetic field of the external space is enhanced and applied to the sensing element 10.

[0053] It should be noted that in the magnetic sensor 200, as long as a predetermined sensitivity can be obtained, the divergence component 30 may not be required.

[0054] As explained above, the clustering member 20 should be able to cluster the magnetic field lines from the external space. Therefore, for the clustering member 20, the width W of the wide portion 20b (-x direction side) where the magnetic field lines enter from the external space is... 20b The width W of the opposite portion 20a (+x direction side) emanating from the clustered magnetic field lines toward the sensing element 10 20a Larger is fine (W) 20a <W 20b ).

[0055] Furthermore, the diverging member 30 can cause the magnetic field lines to diverge into the external space. Therefore, for the diverging member 30, the width W of the magnetic field lines entering from the sensing element 10 on the opposite portion 30a side (-x direction side) is... 30a The width W of the 30b side of the diverging magnetic field lines 30b Narrow is fine (W) 30a <W 30b ).

[0056] It should be noted that, Figure 1 In the case of the beam member 20, the -x direction side of the wide portion 20b is arranged perpendicular (90°) to the magnetic field lines from the external space in the x direction. However, the end of the wide portion 20b of the beam member 20 may not be arranged perpendicular to the magnetic field lines from the external space, and can be set at an angle of 45° or more and 90° or less. It should be noted that the same applies to the diverging member 30.

[0057] In addition, such as Figure 1 As shown by dashed lines, the ends of the wide portion 20b of the focusing member 20 and the wide portion 30b of the diverging member 30 in the magnetic sensor 200 can be tilted at an angle toward the sensing element 10. This obliquely removed portion is where magnetic field lines are difficult to pass through when the magnetic field lines in the focusing member 20 move from the wide portion 20b toward the opposing portion 20a, or when the magnetic field lines in the diverging member 30 move from the opposing portion 30a toward the wide portion 30b. Therefore, even if the ends of the wide portion 20b of the focusing member 20 and the wide portion 30b of the diverging member 30 are tilted at an angle toward the sensing element 10, the impact on the characteristics of magnetic field line focusing or diverging is small.

[0058] Here, for comparison purposes, the sensing element 10, which lacks both the focusing member 20 and the diverging member 30, is referred to as a magnetic sensor 100. It should be noted that the terms "magnetic sensor" are used without distinguishing between magnetic sensors 100 and 200. The same applies to the magnetic sensors described later.

[0059] Figure 2 The figure illustrates another magnetic sensor 210 using the first embodiment.

[0060] The magnetic sensor 210 includes: a sensing element 10; a clustering member 21 that clusters magnetic field lines from external space onto the sensing element 10; and a diverging member 31 that diverges the magnetic field lines that have passed through the sensing element 10. Furthermore, the clustering member 21, the sensing element 10, and the diverging member 31 are arranged in this order along the x-direction.

[0061] The sensing element 10 is the same as the sensing element 10 of the magnetic sensor 200.

[0062] The clustering member 21 includes: a facing portion 21a opposite to the sensing element 10; a wide portion 21b whose width in the y-direction is larger than that of the facing portion 21a; and extension portions 21c and 21d extending from both ends of the wide portion 21b in the x-direction, respectively. It should be noted that the extension portions 21c and 21d are configured parallel to the facing portion 21a. That is, the clustering member 21 has an E-shape in planar shape, with the wide portion 21b as a longitudinal line and the facing portion 21a and the extension portions 21c and 21d as transverse lines. Furthermore, the clustering member 21 has a certain thickness in the z-direction. It should be noted that the facing portion 21a and the wide portion 21b are the same as the facing portion 20a and the wide portion 20b in the magnetic sensor 200.

[0063] In the clustering member 21, the width W (in the y-direction) of the portion of the opposing part 21a opposite to the sensing element 10 21a Length L in the x direction 21a The width W of the portion 20a opposite to the magnetic sensor 200 20a Length L in the x direction 20a Same. The width W in the y-direction of the wide portion 21b. 21b Length L in the x direction 21b The width W of the wide portion 20b of the magnetic sensor 200 20b Length L in the x direction 20b Same. The width W in the y-direction of the extension 21c 21c and the width W in the y direction of the extension 21d 21d For example, the length L in the x-direction of the extension 21c is 2mm. 21c and the length L in the x direction of the extension 21d 21d For example, it is 6mm. Furthermore, the distance L between the opposing portion 21a and the sensing element 10 is... 21ag The distance L between the opposing portion 20a of the clustering member 20 in the magnetic sensor 200 and the sensing element 10. 20ag They are the same. It should be noted that these values ​​are one example, but they can also be other values.

[0064] The diverging member 31 includes: a facing portion 31a opposite to the sensing element 10; a wide portion 31b with a width in the y-direction greater than that of the facing portion 31a; and extension portions 31c and 31d extending from both ends of the wide portion 31b in the -x direction, respectively. It should be noted that the extension portions 31c and 31d are configured parallel to the facing portion 31a. That is, the diverging member 31 has the same planar shape as the focusing member 21, being E-shaped. Furthermore, the diverging member 31 has a certain thickness in the z-direction. It should be noted that the facing portion 31a and the wide portion 31b are the same as the facing portion 30a and the wide portion 30b in the magnetic sensor 200.

[0065] In the diverging member 31, the width W (in the y-direction) of the portion of the opposing part 31a opposite to the sensing element 10 31a Length L in the x direction 31a The width W of the portion 30a opposite to the magnetic sensor 200 30a Length L in the x direction 30a Same. The width W in the y-direction of the wide portion 31b 31b Length L in the x direction 31b The width W of the wide portion 30b of the magnetic sensor 200 30b Length L in the x direction 30b Same. The width W in the y-direction of the extension 31c 31c and the width W in the y direction of the extension 31d 31d For example, the length L in the x-direction of the extension 31c is 2mm. 31c and the length L in the x direction of the extension 31d 31d For example, it is 6mm. Furthermore, the distance L between the opposing portion 31a and the sensing element 10 is... 31ag The distance L between the opposing portion 30a of the diverging member 30 in the magnetic sensor 200 and the sensing element 10. 30ag They are the same. It should be noted that these values ​​are one example, but they can also be other values.

[0066] Incidentally, the magnetic sensor 210 has, in the x-direction, a wide portion 21b of the focusing member 21, a corresponding portion 21a, a sensing element 10, and a corresponding portion 31a and a wide portion 31b of the diverging member 31, arranged sequentially. Furthermore, the focusing member 21 and the diverging member 31 have the same E-shaped planar shape and are arranged symmetrically, sandwiching the sensing element 10 in the x-direction. Hereinafter, the magnetic sensor 210 is described as having an "E-shaped" focusing member 21 and a diverging member 31.

[0067] It should be noted that, Figure 2In the shown clustering member 21, the opposing portion 21a is provided at the center of the wide portion 21b in the y-direction, and the extension portions 21c and 21d are provided at the ends of the wide portion 21b in the ±y-direction. However, the opposing portion 20a may also be provided offset from the center of the wide portion 20b in the +y or -y direction. Alternatively, one of the extension portions 21c and 21d may be omitted. That is, in the clustering member 21, the opposing portion 21a may be provided at one end of the wide portion 21b, and the extension portion 21c or 21d may be provided at the other end of the wide portion 21b. In other words, the planar shape of the clustering member 21 may also be C-shaped. The same applies to the diverging member 31.

[0068] like Figure 2 As shown, magnetic field lines from external space enter the wide portion 21b of the gathering member 21 from the left side (-x direction side) of the attached drawing. A portion of these lines are gathered as they travel from the wide portion 21b towards the opposite portion 21a and are emitted from the opposite portion 21a. It should be noted that another portion of the magnetic field lines already in the wide portion 21b of the gathering member 21 are gathered as they travel towards the extension portions 21c and 21d and are emitted from the extension portions 21c and 21d. Then, the magnetic field lines emitted from the opposite portion 21a pass through the sensing element 10 and enter the opposite portion 31a of the diverging member 31. Additionally, the magnetic field lines emitted from the extension portions 21c and 21d each enter the extension portions 31d and 31c of the diverging member 31. Then, the magnetic field lines diverge as they travel from the opposite portion 31a, extension portions 31c and 31d towards the wide portion 31b and are emitted from the wide portion 31b towards external space. That is, magnetic field lines from external space are bundled by the gathering member 21, thereby increasing the magnetic flux density, which is the density of the magnetic field lines, and allowing it to pass through the sensing element 10. It should be noted that... Figure 2 In this context, the magnetic field of external space (referred to as the external magnetic field) is denoted as magnetic field H.

[0069] As explained above, the gathering member 21 can gather magnetic field lines from the external space to the opposing portion 21a. Therefore, for the gathering member 21, the width W of the wide portion 21b (-x direction side) where the magnetic field lines enter from the external space is... 21b The width W of the opposite portion 21a (+x direction side) emanating from the gathered magnetic field lines toward the sensing element 10 21a Larger is fine (W) 21a <W 21b ).

[0070] Furthermore, the diverging member 31 can cause the magnetic field lines to diverge into the external space. Therefore, for the diverging member 31, the width W of the magnetic field lines entering from the sensing element 10 on the opposite portion 31a side (-x direction side) is... 31a The width W of the wide portion 31b (+x direction side) emanating from the diverging magnetic field lines31b Narrow is fine (W) 31a <W 31b ).

[0071] It should be noted that the distance L0 between the opposing portion 21a of the clustering member 21 and the opposing portion 31a of the diverging member 31 is preferably smaller than or the same as the distance L1 between the extension portion 21c of the clustering member 21 and the extension portion 31d of the diverging member 31, and the distance L2 between the extension portion 21d of the clustering member 21 and the extension portion 31c of the diverging member 31 (L0 ≤ L1, L2). If the distance L1 and / or the distance L2 is smaller than the distance L0, the magnetic reluctance between the extension portion 21c and the extension portion 31d and / or the extension portion 21d and the extension portion 31c (gap) becomes smaller than the magnetic reluctance between the opposing portion 21a and the opposing portion 31a. Therefore, magnetic lines of force tend to concentrate on the side between the extension portion 21c and the extension portion 31d and / or the extension portion 21d and the extension portion 31c (gap), and the magnetic field applied to the sensing element 10 disposed between the opposing portions 21a and the opposing portion 31a becomes smaller.

[0072] Furthermore, the diverging member 31 and the focusing member 21 have the same planar shape and are symmetrically arranged with the sensing element 10 sandwiched in the x-direction. The reason for this is the same as that explained in the magnetic sensor 200. Therefore, in the magnetic sensor 210, the diverging member 31 may not be required as long as a predetermined sensitivity can be obtained.

[0073] In the following text, the clustering member 20 of the magnetic sensor 200 and the clustering member 21 of the magnetic sensor 210 will be referred to as the clustering member. Similarly, the diverging member 30 of the magnetic sensor 200 and the diverging member 31 of the magnetic sensor 210 will be referred to as the diverging member. The same applies in other cases.

[0074] (Sensing element 10)

[0075] Figure 3 The figure illustrates an example of the sensing element 10. Figure 3 (a) is a top view. Figure 3 (b) is along Figure 3 (a) Cross-sectional view of line IIIB-IIIB. Figure 3 In (a), the horizontal direction of the paper is the x-direction, the upward direction of the paper is the y-direction, and the surface direction of the paper is the z-direction. Figure 3 In (b), the horizontal direction of the paper is the x-direction, the upward direction of the paper is the z-direction, and the direction of the back of the paper is the y-direction.

[0076] use Figure 3(b) shows a cross-sectional view illustrating the cross-sectional structure of the sensing element 10. The sensing element 10 includes a substrate 11 and a sensing circuit 12 disposed on the substrate 11.

[0077] use Figure 3 (a) is a top view illustrating the planar structure of the sensing element 10. As an example, the sensing element 10 has a quadrilateral planar shape. The planar shape of the sensing element 10 is several millimeters square. For example, the length in the x-direction is 4mm to 6mm, and the length in the y-direction is 3mm to 5mm. It should be noted that the size of the planar shape of the sensing element 10 can also be other values.

[0078] The sensing circuit 12 includes: a plurality of sensing units 121; a connecting part 122 that connects the sensing units 121 in series in a zigzag shape; and a terminal part 123 that is disposed at one end and the other end of the sensing units 121 connected in series.

[0079] The planar shape of the sensing part 121 is a rectangle with a long side and a short side. Figure 3 (a) The sensing unit 121 shown uses the x-direction as the long side direction and the y-direction as the short side direction. Furthermore, Figure 3 In (a), six sensing elements 121 are arranged side-by-side in the y-direction. Each sensing element 121 is endowed with uniaxial magnetic anisotropy along a direction intersecting the long side direction, for example, a short side direction (width direction) orthogonal to the long side direction. It should be noted that the direction intersecting the long side direction simply needs to have an angle greater than 45° relative to the long side direction. Thus, the sensing element 121 exhibits a magnetoresistive effect. Therefore, the sensing element 10 or the sensing circuit 12 is sometimes described as a magnetoresistive element.

[0080] For each sensing element 121, for example, the length in the long side direction is 1 mm to 10 mm, the width in the short side direction is 50 μm to 150 μm, and the thickness is 0.2 μm to 5 μm. The spacing between adjacent sensing elements 121 is 50 μm to 150 μm. Furthermore, the number of sensing elements 121 is, for example, 18.

[0081] It should be noted that the size (length, area, thickness, etc.) of each sensing element 121, the number of sensing elements 121, and the spacing between sensing elements 121 can be set according to the magnitude of the magnetic field to be sensed, i.e., measured. It should also be noted that there can be only one sensing element 121.

[0082] A connecting portion 122 is disposed between the ends of adjacent sensing portions 121, thereby connecting multiple sensing portions 121 in series. That is, the connecting portion 122 is disposed in such a way that adjacent sensing portions 121 are connected in a zigzag (winding) shape. Figure 3(a) shows a sensing element 10 with six sensing units 121, and five connecting units 122. The number of connecting units 122 varies depending on the number of sensing units 121. For example, when there are four sensing units 121, there are three connecting units 122. Alternatively, when there is only one sensing unit 121, there is no connecting unit 122. It should be noted that the width of the connecting unit 122 can be set according to the current flowing in the sensing circuit 12. For example, the width of the connecting unit 122 can be the same as that of the sensing unit 121.

[0083] Terminal portion 123 is disposed at one end and the other end of the sensing portion 121 which are connected in series. Figure 3 In (a), a terminal portion 123a is provided on the lower side of the paper, and a terminal portion 123b is provided on the upper side of the paper. When terminal portions 123a and 123b are not distinguished, they are referred to as terminal portion 123. Terminal portion 123 is simply large enough to connect a wire. It should be noted that... Figure 3 In the sensing element 10 shown in (a), there are 6 sensing portions 121, so the terminal portions 123a and 123b are located on the left side of the paper. When the number of sensing portions 121 is odd, the two terminal portions 123a and 123b can be arranged on the left and right sides of the paper. It should be noted that the sensing element 10 can also be configured by reversing the left and right sides.

[0084] As explained above, the sensing circuit 12 is configured such that the sensing units 121 are connected in series in a zigzag shape via the connecting units 122, and current flows through the terminal units 123a and 123b provided at both ends. Therefore, it is referred to as the sensing circuit 12.

[0085] The substrate 11 is a non-magnetic substrate, such as an electrically insulating oxide substrate like glass or sapphire, a semiconductor substrate like silicon, or a metal substrate like aluminum, stainless steel, or a metal plated with nickel phosphide. It should be noted that when the substrate 11 is a semiconductor substrate like silicon, or a metal substrate like aluminum, stainless steel, or a metal plated with nickel phosphide, and has high conductivity, it is preferable to provide an insulating layer on the surface of the substrate 11 on the side where the sensing circuit 12 is disposed, electrically insulating the substrate 11 from the sensing circuit 12. Examples of insulating materials constituting such an insulating layer include oxides such as SiO2, Al2O3, and TiO2, or nitrides such as Si3N4 and AlN. Here, the substrate 11 is described as glass. In such a substrate 11, the thickness is, for example, 0.3 mm to 2 mm. It should be noted that the thickness can also be other values.

[0086] As the soft magnetic material constituting the sensing element 121, an amorphous alloy formed by adding high-melting-point metals such as Nb, Ta, and W to an alloy with Co as the main component is preferable. Examples of Co alloys constituting the sensing element 121 include CoNbZr, CoFeTa, and CoWZr. Such a soft magnetic material constituting the sensing element 121 can be formed using a sputtering method.

[0087] The connecting portion 122 and the terminal portion 123 in the sensing circuit 12 are integrally formed with the sensing portion 121. It should be noted that one or both of the connecting portion 122 and the terminal portion 123 can be constructed using a conductive material. Examples of such conductive materials for the connecting portion 122 and the terminal portion 123 include Ag, Cu, Au, and Al. It should be noted that different conductive materials can be used to construct the connecting portion 122 and the terminal portion 123. It should be noted that if the connecting portion 122 and the terminal portion 123 are integrally formed with the sensing portion 121, it is not necessary to form the sensing portion 121 separately from the connecting portion 122 and the terminal portion 123. It should be noted that after the connecting portion 122 and the terminal portion 123 are integrally formed with the sensing portion 121, a conductive material can be superimposed on the connecting portion 122 and / or the terminal portion 123.

[0088] In the above description, the sensing element 121 is composed of a single layer of soft magnetic material (referred to as a soft magnetic material layer). However, the soft magnetic material layer can also consist of two layers: an upper soft magnetic material layer and a lower soft magnetic material layer. An antiferromagnetic coupling layer is provided between the upper and lower soft magnetic material layers to enable antiferromagnetic coupling (AFC) between them. Examples of such an antiferromagnetic coupling layer include Ru. By providing an antiferromagnetic coupling layer, the generation of a counter-magnetic field can be suppressed, thereby improving the sensitivity of the sensing element 10.

[0089] Additionally, a conductive layer can be provided between the upper and lower soft magnetic layers constituting the sensing unit 121 to reduce the resistance of the sensing unit 121. As the conductive layer, a metal or alloy with high conductivity is preferred, and a metal or alloy with high conductivity and no magnetic properties is more preferred. Examples of such conductive layers include aluminum, copper, and silver. The thickness of the conductive layer is, for example, 10 nm to 500 nm. By providing a conductive layer, the frequency of the alternating current flowing in the sensing circuit 12 can be increased.

[0090] Furthermore, a domain suppression layer can be provided between the upper and lower soft magnetic layers constituting the sensing unit 121 to suppress the generation of closed magnetic domains in both layers. Examples of such a domain suppression layer include non-magnetic materials such as Ru and SiO2, and non-magnetic amorphous metals such as CrTi, AlTi, CrB, CrTa, and CoW. By providing the domain suppression layer to suppress the generation of closed magnetic domains in the sensing unit 121, noise generated based on the movement of magnetic walls and caused by the so-called Barkhausen effect can be suppressed.

[0091] It should be noted that the soft magnetic layer constituting the sensing unit 121 can also be a multilayer structure with more than two layers, and an antiferromagnetic coupling layer, a conductive layer, or a domain suppression layer can be provided between each layer. Alternatively, two or all of the above-mentioned antiferromagnetic coupling layer, conductive layer, and domain suppression layer can be used in combination.

[0092] (Function of sensing element 10)

[0093] Next, the function of the sensing element 10 will be explained.

[0094] Figure 4 This figure illustrates the relationship between the magnetic field H applied along the long side of the sensing section 121 of the sensing element 10 and the impedance Z of the sensing element 10. Figure 4 In the diagram, the horizontal axis represents the magnetic field H, and the vertical axis represents the impedance Z. It should be noted that, for the impedance Z, in... Figure 3 (a) The alternating current is passed between the terminals 123a and 123b of the sensing circuit 12 shown in (a) for measurement. Therefore, the impedance Z is the impedance of the sensing circuit 12, and is recorded as the impedance Z of the sensing element 10.

[0095] like Figure 4 As shown, the impedance Z of the sensing element 10 increases as the magnetic field H applied in the long side direction of the sensing section 121 increases. Furthermore, when the applied magnetic field H is greater than the anisotropic magnetic field Hk, the impedance Z of the sensing element 10 decreases. Within a range smaller than the anisotropic magnetic field Hk of the sensing section 121, when using the steep portion (ΔZ / ΔH) of the change in impedance Z relative to the change in magnetic field H, the slight change in magnetic field H can be extracted as the change in impedance Z ΔZ. Figure 4 In this context, the center of a magnetic field H with a large ΔZ / ΔH is denoted as the magnetic field Hb. That is, it is possible to measure the vicinity of the magnetic field Hb with high precision. Figure 4The change in magnetic field H (ΔH) within the range indicated by the middle arrow. Here, the sensitivity is the value (Zmax / Zb) obtained by dividing the steepest part of the change in impedance Z (ΔZ / ΔH maximum), i.e., the change in impedance per unit magnetic field in magnetic field Hb, by the impedance Z at magnetic field Hb (referred to as impedance Zb). The higher the sensitivity, the greater the magnetoresistance effect, and the easier it is to measure the magnetic field or its change. In other words, the steeper the change in impedance Z relative to magnetic field H, the higher the sensitivity. Magnetic field Hb is sometimes called the bias magnetic field. In the following text, magnetic field Hb will be referred to as bias magnetic field Hb. It should be noted that the higher the frequency of the alternating current flowing in the induction circuit 12, the higher the sensitivity.

[0096] (The relationship between the impedance Z of magnetic sensors 200 and 210 and the magnetic field H)

[0097] Figure 5 The figure illustrates the relationship between impedance Z and magnetic field H in the magnetic sensors 200 and 210 of the first embodiment. Figure 5 In the diagram, the horizontal axis represents the magnetic field H (Oe), and the vertical axis represents the impedance Z (Ω). Figure 5 The impedance Z of the magnetic field H is shown in the range of ±15 Oe. Furthermore, Figure 5 In addition to the magnetic sensor 200 with a "T-shaped" clustering member 20 and a diverging member 30, and the magnetic sensor 210 with an "E-shaped" clustering member 21 and a diverging member 31, a magnetic sensor 100 consisting of a sensing element 10 without a clustering member and a diverging member is also shown for comparison. Hereinafter, the magnetic sensor 200 with a "T-shaped" clustering member 20 and a diverging member 30 will be referred to as magnetic sensor 200 ("T-shaped"), the magnetic sensor 210 with an "E-shaped" clustering member 21 and a diverging member 31 will be referred to as magnetic sensor 210 ("E-shaped"), and the magnetic sensor 100 consisting of a sensing element 10 without a clustering member and a diverging member will be referred to as magnetic sensor 100 ("none"). Furthermore, Figure 5 In this diagram, magnetic sensor 200 (“T-type”) is designated as “T-type”, magnetic sensor 210 (“E-type”) is designated as “E-type”, and magnetic sensor 100 (“none”) is designated as “none”. The same applies to other diagrams.

[0098] Compared to magnetic sensor 100 (“None”), magnetic sensor 200 (“T-type”) and magnetic sensor 210 (“E-type”) exhibit anisotropic magnetic fields Hk (see [reference]). Figure 4 As the magnetic field H decreases, the impedance Z changes steeply relative to the magnetic field H. It should be noted that, compared to the magnetic sensor 210 (“Type E”), the magnetic sensor 200 (“Type T”) has a smaller anisotropic magnetic field Hk, resulting in a steeper change in impedance Z relative to the magnetic field H.

[0099] Figure 6 The graph shows the sensitivity Zmax / Zb and anisotropic magnetic field Hk of the magnetic sensors 200 and 210 using the first embodiment. The left vertical axis represents the sensitivity Zmax / Zb ( / Oe), and the right vertical axis represents the anisotropic magnetic field Hk (Oe). Figure 6 It is based on Figure 5 The graph shows the relationship between impedance Z and magnetic field H, from which the values ​​of sensitivity Zmax / Zb and anisotropic magnetic field Hk are extracted and displayed. It should be noted that... Figure 6 In addition to magnetic sensor 200 (“T-type”) and magnetic sensor 210 (“E-type”), magnetic sensor 100 (“none”) is also shown for comparison.

[0100] like Figure 6 As shown, compared to magnetic sensor 100 (“none”), magnetic sensors 200 (“T-type”) and 210 (“E-type”) have smaller anisotropic magnetic fields Hk, resulting in improved sensitivity Zmax / Zb. Furthermore, it is evident that compared to magnetic sensor 210 (“E-type”), magnetic sensor 200 (“T-type”) has an even smaller anisotropic magnetic field Hk, further improving sensitivity Zmax / Zb.

[0101] This is believed to be because by equipping the sensing element 10 with a clustering member and a diverging member, such as magnetic sensors 200 and 210, the magnetic flux density through the sensing element 10 increases, and the magnetic field applied to the sensing element 10 becomes larger.

[0102] Figure 7 The figure illustrates a modified example of the magnetic sensor 200 of the first embodiment. Figure 7 (a) is a magnetic sensor 220 having a trapezoidal planar clustering member 22 and a diverging member 32. Figure 7 (b) is a magnetic sensor 230 having a Y-shaped bundle member 23 and a diverging member 33.

[0103] like Figure 7 As shown in (a), the magnetic sensor 220 is obtained by replacing the T-shaped planar clustering member 20 and diverging member 30 in the magnetic sensor 200 (“T-type”) with a trapezoidal planar clustering member 22 and diverging member 32. Therefore, the magnetic sensor 220 is referred to as the magnetic sensor 220 (“trapezoidal type”). Regarding the clustering member 22, the lower base of the trapezoid is positioned on the side where magnetic field lines enter from the external space in the -x direction, and the upper base of the trapezoid is positioned on the side opposite to the sensing element 10. In the clustering member 22, the width W in the y-direction of the upper base opposite to the sensing element 10... 22a The width W of the lower base in the y-direction of the magnetic field lines entering from the outer space. 22b Small (W)22a <W 22b Similarly, for the diverging member 32, the upper base of the trapezoid is positioned on the side opposite to the sensing element 10, and the lower base is positioned on the side where the magnetic field lines radiate outwards in the +x direction. In the diverging member 32, the width W in the y-direction of the upper base opposite to the sensing element 10... 32a The width W of the lower base emanating from the magnetic field lines into external space. 32b Small (W) 32a <W 32b That is, the focusing member 22 and the diverging member 32 are symmetrically arranged in the x-direction, sandwiching the sensing element 10. In this way, the focusing member 22 focuses magnetic field lines entering from the external space onto the sensing element 10. Meanwhile, the diverging member 32 diverges the magnetic field lines that have passed through the sensing element 10. Compared to the magnetic sensor 200 ("T-type"), the magnetic sensor 220 ("trapezoidal type") has lower magnetic resistance in both the focusing member and the diverging member. It should be noted that the planar shapes of the focusing member 22 and the diverging member 32 of the magnetic sensor 220 ("trapezoidal type") may not be symmetrical in the y-direction.

[0104] like Figure 7 As shown in (b), the magnetic sensor 230 is obtained by replacing the T-shaped planar clustering member 20 and the diverging member 30 in the magnetic sensor 200 (“T-type”) with a Y-shaped planar clustering member 23 and the diverging member 33. Therefore, the magnetic sensor 230 is referred to as the magnetic sensor 230 (“Y-type”). Regarding the clustering member 23, the wider portion of the Y-shape is positioned on the side where the magnetic field lines enter from the external space in the -x direction, and the narrower portion of the Y-shape is positioned on the side opposite to the sensing element 10. The width W in the y-direction of the clustering member 23 on the side opposite to the sensing element 10... 23a The width W in the y-direction of the side where the magnetic field lines enter from the external space. 23b Small (W) 23a <W 23b Similarly, for the diverging member 33, the narrow portion of the Y-shape is positioned on the side opposite to the sensing element 10, and the wide portion of the Y-shape is positioned on the side where the magnetic field lines radiate outwards in the +x direction. In the diverging member 33, the width W in the y-direction on the side opposite to the sensing element 10... 33a The width W in the y-direction of the side of the magnetic field lines emanating into external space. 33b Small (W) 33a <W 33bThat is, the focusing member 23 and the diverging member 33 are symmetrically arranged in the x-direction, sandwiching the sensing element 10. In this way, the focusing member 23 focuses the magnetic field lines entering from the external space onto the sensing element 10. In addition, the diverging member 33 diverges the magnetic field lines that have passed through the sensing element 10. It should be noted that the wide portion of the Y-shape of the focusing member 23 and the diverging member 33 in the magnetic sensor 230 (“Y-type”) may only be one side. Alternatively, the planar shape of the focusing member 23 and the diverging member 33 may be V-shaped.

[0105] As mentioned above, the clustering member gathers the magnetic field lines from the external magnetic field, increasing the magnetic flux density and allowing them to pass through the induction element 10. The diverging member causes the magnetic field lines that have passed through the induction element 10 to diverge and be emitted outward. Therefore, as Figure 7 (a) The clustering component 22 of the magnetic sensor 220, and Figure 7 (b) As with the gathering member 23 of the magnetic sensor 230, the gathering member can be a member that gathers the magnetic field lines generated by an external magnetic field. Additionally, as... Figure 7 (a) the diverging component 32 of the magnetic sensor 220, and Figure 7 (b) The diverging member 33 of the magnetic sensor 230 is shown. The diverging member can be a member that causes the magnetic field lines to diverge outward into the external space.

[0106] Therefore, for the clustering member, the width of the side where the magnetic field lines from the external space enter, i.e., the side farther from the sensing element 10, should be larger than the width of the side with the sensing element 10. Similarly, for the diverging member, the width of the side where the magnetic field lines radiate outward, i.e., the side farther from the sensing element 10, should be larger than the width of the side with the sensing element 10.

[0107] [Second Implementation]

[0108] In the first embodiment, the bias magnetic field Hb applied to the sensing element 10 is applied in an overlapping manner with an external magnetic field from the external space. In the second embodiment, the bias magnetic field Hb is applied by a permanent magnet positioned in close proximity to or in contact with either or both of the focusing member and the diverging member.

[0109] Figure 8 The diagram illustrates the application of the magnetic sensor 300 according to the second embodiment. The magnetic sensor 300 includes... Figure 1 The magnetic sensor 200 and permanent magnet 40 are shown. Therefore, for... Figure 1The same parts of the magnetic sensor 200 shown are labeled with the same reference numerals and descriptions are omitted. As the permanent magnet 40, a disk-shaped permanent magnet can be used, for example. Examples of such a permanent magnet 40 include ferrite magnets with a diameter of 1 mm to 5 mm and a thickness of 0.1 mm to 2 mm. The permanent magnet 40 is an example of a bias magnetic field application member.

[0110] In the magnetic sensor 300, the permanent magnet 40 is disposed in contact with the sensing element 10 side at the -y direction side end of the wide portion 20b of the clustering member 20. The position where the permanent magnet 40 is disposed is denoted as position A. Figure 8 In the text, it is recorded as [A]. The others are the same. ). At this time, it is arranged such that the N pole of the permanent magnet 40 is on the wide portion 20b side of the clustering member 20.

[0111] As indicated by the thick arrow, magnetic field lines emanating from the N pole of the permanent magnet 40 pass through the sensing element 10 via the wide portion 20b of the converging member 20 and the opposing portion 20a. Then, the magnetic field lines passing through the sensing element 10 return to the S pole of the permanent magnet 40 via the opposing portion 30a of the diverging member 30 and the wide portion 30b. In other words, the magnetic field lines from the permanent magnet 40 pass through the sensing element 10 via the converging member 20 and the diverging member 30, thereby applying a bias magnetic field Hb to the sensing element 10.

[0112] It should be noted that in the magnetic sensor 300 (“T-type + permanent magnet”), the magnetic field lines travel a distance L3 when returning from the wide portion 30b of the diverging member 30 to the permanent magnet 40.

[0113] It should be noted that, in addition to being located at position A, the permanent magnet 40 can also be located at any of the following positions: the side of the sensing element 10 at the +y direction end of the wide portion 20b of the clustering member 20 (position B), the side of the sensing element 10 at the -y direction end of the wide portion 30b of the diverging member 30 (position C), and the side of the sensing element 10 at the +y direction end (position D).

[0114] Alternatively, it can be disposed at the -y direction side end of the wide portion 20b of the clustering member 20 (position E). Furthermore, the permanent magnet 40 can be disposed at the -y direction side end of the wide portion 20b of the clustering member 20, on the side opposite to the sensing element 10 (position F), or it can be disposed on the side of the wide portion 20b of the clustering member 20 on the sensing element 10 side, in a portion close to the opposing portion 20a (position G). Positions A to G shown here are examples; the permanent magnet 40 can also be disposed in portions other than positions A to G. Additionally, multiple permanent magnets 40 can be disposed at multiple positions (positions A to G, etc.). The multiple permanent magnets 40 used in this case can be permanent magnets with the same performance or permanent magnets with different performance. It should be noted that... Figure 8 Similarly, as shown in the case where the permanent magnet 40 is set at position A, the permanent magnet 40 can be configured such that the magnetic field lines from the permanent magnet 40 pass through the sensing element 10 to apply a bias magnetic field Hb.

[0115] Figure 9 This diagram illustrates the detection sensitivity of the magnetic sensor 300 using the second embodiment. The horizontal axis represents AC voltage (V), and the vertical axis represents detection sensitivity (mV / nT). Here, the magnetic sensor 300 is referred to as magnetic sensor 300 (“T-type + permanent magnet”). Figure 9 The text describes it as "T-type + permanent magnet". Furthermore, Figure 9 In addition to the magnetic sensor 300 (“T-type + permanent magnet”), a magnetic sensor 100 (“none”) is also shown.

[0116] The detection sensitivity is the voltage of the sensing element 10 per unit magnetic field when the magnetic sensor (magnetic sensor 300 ("T-type + permanent magnet"), magnetic sensor 100) is set in the AM modulation circuit and an AC voltage is applied.

[0117] like Figure 9 As shown, the detection sensitivity of the magnetic sensor 300 ("T-type + permanent magnet") is more than twice that of the magnetic sensor 100 ("none").

[0118] In addition, in terms of noise density, it is 38 pT / √Hz in magnetic sensor 100 (“None”) and 12.4 pT / √Hz in magnetic sensor 300 (“T-type + permanent magnet”), which is nearly 3 times higher.

[0119] Figure 10 A graph of a magnetic sensor used to illustrate the relationship between the method of applying the bias magnetic field Hb and noise. Figure 10(a) A magnetic sensor 300 having a “T-shaped” clustering member 20 and a diverging member 30, and using a permanent magnet 40 to apply a bias magnetic field Hb. Figure 10 (b) A magnetic sensor 400 that uses a bonded magnet 50 to apply a bias magnetic field Hb.

[0120] Figure 10 (a) is Figure 8 The magnetic sensor 300 shown (“T-type + permanent magnet”) has a permanent magnet 40 at position A.

[0121] Figure 10 (b) The magnetic sensor 400 includes a sensing element 10 and bonding magnets 50a and 50b. Furthermore, the bonding magnets 50a and 50b are arranged along the y-direction such that they sandwich the sensing element 10. It should be noted that, without distinguishing between the bonding magnets 50a and 50b, they are referred to as bonding magnet 50. Additionally, bonding magnet 50 is sometimes referred to simply as bonding magnet. A bonding magnet is a rod-shaped permanent magnet obtained by mixing and molding tiny magnetic particles or powders with a binder such as resin. It should be noted that the magnetic sensor 400 that uses the bonding magnet 50 to apply a bias magnetic field Hb is referred to as magnetic sensor 400 (“bonded magnet”).

[0122] Figure 11 This figure illustrates the noise in a magnetic sensor 300 (“T-type + permanent magnet”) that has a “T-shaped” clustering member 20 and a diverging member 30, and applies a bias magnetic field Hb using a permanent magnet 40. Figure 11 (a) shows the time-varying voltage of sensing element 10. Figure 11 (b) is the FFT data obtained by performing a Fast Fourier Transform (FFT) on the time-varying voltage. Figure 11 In (a), the horizontal axis represents time (sec) and the vertical axis represents voltage (V). Figure 11 In (b), the horizontal axis represents frequency (Hz), and the vertical axis represents FFT data (mV / √Hz). It should be noted that the voltage of the sensing element 10 is the voltage of the sensing element 10 when it is connected to the AM modulation circuit and an AC voltage is applied. Furthermore, Figure 11 In (a), the results of the four measurements are shown overlaid. Figure 11 (b) shows one of the four measurements.

[0123] Figure 12 A figure illustrating noise in a magnetic sensor 400 (“bonded magnet”) that uses a bonding magnet 50 to apply a bias magnetic field Hb. Figure 12 (a) shows the time-varying voltage of sensing element 10. Figure 12(b) is the FFT data obtained by performing a Fast Fourier Transform (FFT) on the time-varying voltage. Figure 12 In (a), the horizontal axis represents time (sec) and the vertical axis represents voltage (V). Figure 12 In (b), the horizontal axis represents frequency (Hz), and the vertical axis represents FFT data (mV / √Hz). It should be noted that the voltage of the sensing element 10 is the same as in the case of the magnetic sensor 300. Furthermore, Figure 12 In (a), the results of the four measurements are shown overlaid. Figure 12 (b) shows one of the four measurements.

[0124] Figure 11 (a) shows the magnetic sensor 300 (“T-type + permanent magnet”) and Figure 12 Compared to the magnetic sensor 400 (“bonded magnet”) shown in (a), the voltage variation (fluctuation) with respect to time is less. That is, compared to the magnetic sensor 400 (“bonded magnet”), the generation of noise related to voltage fluctuations with respect to time is suppressed in the magnetic sensor 300 (“T-type + permanent magnet”). Figure 12 Compared to the magnetic sensor 400 (“bonded magnet”) shown in (a), in Figure 11 A stable voltage can be obtained in the magnetic sensor 300 (“T-type + permanent magnet”) shown in (a).

[0125] in addition, Figure 11 (b) shows the magnetic sensor 300 (“T-type + permanent magnet”) and Figure 12 Compared to the magnetic sensor 400 (“bonded magnet”) shown in (b), the FFT data at frequencies from 10 Hz to 100 Hz shows less variation. Especially... Figure 11 (b) shows the magnetic sensor 300 (“T-type + permanent magnet”), Figure 12 (b) The noise appearing around 30 Hz in the magnetic sensor 400 (“bonded magnet”) shown is suppressed. This is believed to be because the heat capacity of the clustering member 20 and the diverging member 30 is much more stable in the magnetic sensor 300 (“T-type + permanent magnet”) compared to the bonded magnet 50.

[0126] In the magnetic sensor 400 (“bonded magnet”), magnetic field lines from the bonded magnet 50 tend to emanate into the external space. In contrast, in the magnetic sensor 300 (“T-type + permanent magnet”), because the gathering member 20 and the diverging member 30 are provided, and the bias magnetic field Hb is applied using the permanent magnet 40, the magnetic field lines generated by the permanent magnet 40 are easily confined within the gathering member and the diverging member. This is believed to be because, in the bonded magnet 50, magnetic field lines tend to emanate into the external space, and the bias magnetic field Hb is prone to variation. Therefore, it is believed that the magnetic sensor 300 (“T-type + permanent magnet”) can suppress noise generation compared to the magnetic sensor 400 (“bonded magnet”).

[0127] However, in the magnetic sensor 300 (“T-type + permanent magnet”), in Figure 8 With a permanent magnet 40 positioned at location E, a greater than Figure 11 The noise shown in (a) and (b) is large. This is believed to be because the magnetic field lines generated by the permanent magnet 40 are not only within the clustering member 20 and the diverging member 30, but also easily emitted into the external space.

[0128] Figure 13 This figure illustrates another magnetic sensor 310 using the second embodiment. The magnetic sensor 310 includes... Figure 2 The magnetic sensor 210 (“Type E”) and permanent magnet 40 are shown. Therefore, for... Figure 2 The same parts of the magnetic sensor 210 (“Type E”) shown are labeled with the same reference numerals and descriptions are omitted. As for the permanent magnet 40, similarly to the magnetic sensor 300 (“Type T + Permanent Magnet”), a disk-shaped permanent magnet can be used. Therefore, the permanent magnet is referred to as permanent magnet 40. Furthermore, the magnetic sensor 310 is referred to as magnetic sensor 310 (“Type E + Permanent Magnet”).

[0129] In the magnetic sensor 310, the permanent magnet 40 is positioned in contact with the +x direction side end (position I) of the extension 21c of the clustering member 21. At this time, the permanent magnet 40 is positioned with its N pole facing the extension 21c of the clustering member 21. As indicated by the thick arrow, magnetic field lines emanating from the N pole of the permanent magnet 40 pass through the extension 21c, the wide portion 21b, and the opposing portion 21a of the clustering member 21 and then through the sensing element 10. The magnetic field lines that have passed through the sensing element 10 then return to the S pole of the permanent magnet 40 via the opposing portion 31a, the wide portion 31b, and the extension 31d of the diverging member 31. In other words, the magnetic field lines from the permanent magnet 40 pass through the sensing element 10 via the clustering member 21 and the diverging member 31, thereby applying a bias magnetic field Hb to the sensing element 10.

[0130] It should be noted that, in addition to position I, the permanent magnet 40 can also be disposed at any of the following positions: the +x direction end (position J) of the extension 21d of the clustering member 21, the -x direction end (position K) of the extension 31c of the diverging member 31, and the -x direction end (position M) of the extension 31d of the diverging member 31. It should be noted that positions I to M are examples, and it can also be disposed at other positions. Multiple permanent magnets 40 can also be disposed at multiple positions (positions I to M, etc.).

[0131] It should be noted that, Figure 13 In the magnetic sensor 310 (“Type E + Permanent Magnet”) shown, the focusing member 21 has extensions 21c and 21d, and the diverging member 31 has extensions 31c and 31d. Furthermore, the extension 21c of the focusing member 21 is opposite to the extension 31d of the diverging member 31. Similarly, the extension 21d of the focusing member 21 is opposite to the extension 31c of the diverging member 31. Therefore, as... Figure 13 As shown, the magnetic field lines travel a distance L4 when they return from the extension 31d of the diverging member 31 to the permanent magnet 40.

[0132] on the other hand, Figure 8 In the magnetic sensor 300 (“T-type + permanent magnet”), the magnetic field lines travel a distance L3 when returning from the wide portion 30b of the diverging member 30 to the permanent magnet 40. In the magnetic sensor 310 (“E-type + permanent magnet”), the diverging member 31 has an extension 31d, therefore, the distance L4 is shorter than the distance L3 (L4 < L3). Therefore, compared to the magnetic sensor 300 (“T-type + permanent magnet”), the magnetic field lines returning to the permanent magnet 40 are less likely to leak into the external space in the magnetic sensor 310 (“E-type + permanent magnet”). That is, compared to the magnetic sensor 300 (“T-type + permanent magnet”), the magnetic sensor 310 (“E-type + permanent magnet”) is better at suppressing noise generation.

[0133] It should be noted that electromagnetic field analysis was performed on the magnetic field strength of the sensing element 10 portion in both the magnetic sensor 300 (“T-type + permanent magnet”) and the magnetic sensor 310 (“E-type + permanent magnet”). Here, the planar shape of the magnetic sensor 300 (“T-type + permanent magnet”) is such that the extensions 21c and 21d of the clustering member 21 and the extensions 31c and 31d of the diverging member 31 in the magnetic sensor 310 (“E-type + permanent magnet”) are removed. Therefore, in terms of the magnetic field strength in the sensing element 10, it is 2.78 times stronger in the magnetic sensor 300 (“T-type + permanent magnet”) and 2.25 times stronger in the magnetic sensor 310 (“E-type + permanent magnet”) compared to the magnetic sensor 100 (“none”) which lacks both the clustering and diverging members.

[0134] This is believed to be because, in the magnetic sensor 300 (“T-type + permanent magnet”), the magnetic field lines are clustered at the opposing portions 20a and 30a, while in the magnetic sensor 310 (“E-type + permanent magnet”), the magnetic field lines are clustered not only at the opposing portions 21a and 31a, but also at the extension portions 21c, 21d, 31c, and 31d (see [link to relevant documentation]). Figure 1 , Figure 2 ).

[0135] However, when multiple magnetic sensors are arranged in a row, the bias magnetic field Hb used in each magnetic sensor may affect the other magnetic sensors in the row. In such cases, it is advisable to use a magnetic sensor 310 ("Type E + permanent magnet") whose bias magnetic field Hb is not easily leaked.

[0136] It should be noted that in magnetic sensor 300 (“T-type + permanent magnet”) and magnetic sensor 310 (“E-type + permanent magnet”), the permanent magnet 40 is arranged in a manner that contacts the clustering member and / or the diverging member, but the permanent magnet 40 may also be arranged in a manner that is close to the clustering member and / or the diverging member.

[0137] Furthermore, the permanent magnet 40 that applies a bias magnetic field Hb to the sensing element 10 can be in conjunction with... Figure 7 (a) The magnetic sensor 220 shown has a trapezoidal planar shape, with the clustering member 22 and / or the diverging member 32 positioned close to or in contact with it. It can also be positioned in conjunction with... Figure 7 (b) The magnetic sensor 230 shown has a planar shape of Y-shaped clustering member 23 and / or diverging member 33 arranged in a manner that is close to or in contact with it.

[0138] The embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. The clustering and diverging components shown in each of the magnetic sensors 200, 210, 220, 230, 300, and 310 using this embodiment can be combined for use. That is, various modifications and combinations are possible as long as the spirit of the present invention is not violated.

Claims

1. A magnetic sensor, which has the following characteristics: The sensing element has a sensing circuit on the substrate, which uses the sensing circuit to sense the magnetic field through the magnetoresistance effect; A clustering member is disposed opposite to the sensing element. The clustering member is a different member from the sensing element. The clustering member is made of a soft magnetic material and clusters magnetic lines of force from the outside onto the sensing element. A diverging member, which is different from the sensing element and the focusing member, is arranged opposite to the sensing element from the opposite side of the side opposite to the focusing member. The diverging member is made of a soft magnetic material and causes the magnetic lines of force passing through the sensing element to diverge outward. and A bias magnetic field applying member is provided, wherein the bias magnetic field applying member is in contact with either the focusing member or the diverging member, but not with the other of the focusing member or the diverging member, and applies a bias magnetic field to the sensing element through the focusing member and the diverging member. The clustering member includes: a facing portion opposite to the sensing element; and a wide portion, wherein the wide portion of the clustering member is provided on the side where magnetic field lines enter from the outside, and its width in the direction intersecting the direction of the external magnetic field lines is larger than that of the facing portion of the clustering member, and the wide portion extends to both sides of the facing portion of the clustering member. The diverging member includes: a facing portion opposite to the sensing element; and a wide portion, the wide portion of the diverging member being provided on the side where magnetic field lines radiate outward, and its width in the direction intersecting the direction of the external magnetic field lines is wider on both sides than the facing portion of the diverging member. The bias magnetic field applying member is in contact with any one of the wide portion of the bundle member that expands towards the opposite side of the bundle member, or the wide portion of the diverging member that expands towards the opposite side of the diverging member, and is opposite to any other one of the wide portion of the bundle member that expands towards the opposite side of the bundle member, or the wide portion of the diverging member that expands towards the opposite side of the diverging member.

2. A magnetic sensor, which has the following characteristics: The sensing element has a sensing circuit on the substrate, which uses the sensing circuit to sense the magnetic field through the magnetoresistance effect; A clustering member is disposed opposite to the sensing element. The clustering member is a different member from the sensing element. The clustering member is made of a soft magnetic material and clusters magnetic lines of force from the outside onto the sensing element. A diverging member, which is different from the sensing element and the focusing member, is arranged opposite to the sensing element from the opposite side of the side opposite to the focusing member. The diverging member is made of a soft magnetic material and causes the magnetic lines of force passing through the sensing element to diverge outward. and A bias magnetic field applying member is provided, wherein the bias magnetic field applying member is in contact with either the focusing member or the diverging member, but not with the other of the focusing member or the diverging member, and applies a bias magnetic field to the sensing element through the focusing member and the diverging member. The clustering member includes: an opposing portion opposite to the sensing element; The wide portion of the clustering member is provided on the side where magnetic lines of force enter from the outside, and its width in the direction intersecting the direction of the external magnetic lines of force is wider on both sides than the opposite portion of the clustering member; and the extension portion extends from the end of the wide portion of the clustering member toward the sensing element side. The diverging member includes: an opposing portion opposite to the sensing element; The wide portion of the diverging member is located on the side where the magnetic field lines radiate outward, and its width in the direction intersecting the direction of the external magnetic field lines is wider on both sides than the opposite portion of the diverging member; and the extension portion extends from the end of the wide portion of the diverging member toward the sensing element side. The bias magnetic field applying member is in contact with either the end of the extension of the clustering member on the sensing element side or the end of the extension of the diverging member on the sensing element side, and is opposite to either the other end of the extension of the clustering member on the sensing element side or the end of the extension of the diverging member on the sensing element side.

3. The magnetic sensor as described in claim 1 or 2, characterized in that, The clustering member and the diverging member are disposed on the outside of the substrate.

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