Magnetic sensor, electric control device, correction method, and manufacturing method of magnetic sensor

Abstract

The present application provides a kind of magnetic sensor, electric control device, correction method and the manufacturing method of magnetic sensor. Regardless of the direction of the applied external magnetic field, the linearity of the output signal is good, and the magnetic sensor includes a magnetic detection part that outputs a signal by the application of a magnetic field, and a signal correction part that corrects the signal output from the magnetic detection part. The magnetic detection part includes a magnetoresistance effect element with a specified sensitivity axis. The signal correction part uses a correction value that can reduce the distortion error contained in the signal when a magnetic field in the cross direction intersecting the sensitivity axis is applied to the magnetoresistance effect element to correct the signal, and generates a corrected signal.

Description

Technical Field

[0001] This invention relates to a magnetic sensor and an electrical control device using the same, as well as a method for correcting the output signal of the magnetic sensor and a method for manufacturing the magnetic sensor. Background Technology

[0002] In recent years, position detection devices for detecting the position, amount of movement (change), and orientation of a moving body resulting from linear movement have been used in various applications. One known position detection device includes a magnetic sensor unit that outputs a signal by applying a magnetic field. For example, a laminate having a free layer and a magnetized fixed layer can be described, which includes a magnetoresistive element (MR element) whose resistance changes with the direction of the easy magnetization axis of the free layer corresponding to an external magnetic field.

[0003] The magnetoresistive element of the aforementioned magnetic sensor unit has a sensitivity axis that is parallel to the magnetization direction of the magnetization fixing layer. By applying an external magnetic field along the direction of the sensitivity axis to the magnetoresistive element, a signal corresponding to the magnetic field strength of the external magnetic field is output.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent document 1: Japanese Patent Application Publication No. 2019-117184. Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] Depending on the operating environment of the position detection device, sometimes an external magnetic field (hereinafter sometimes referred to as a "tilted magnetic field") that is obliquely crossed relative to the sensitivity axis is applied to the magnetoresistive element. In this case, the distortion caused by higher harmonic components, such as the third harmonic component, in the signal output from the magnetic sensor unit increases. Consequently, the linearity of the output signal from the magnetic sensor unit deteriorates when a tilted magnetic field is applied to the magnetoresistive element.

[0009] In view of the above problems, the object of the present invention is to provide a magnetic sensor that has good linearity of output signal regardless of the direction of the applied external magnetic field, an electrical control device using the magnetic sensor, a method for correcting the output signal of the magnetic sensor, and a method for manufacturing the magnetic sensor.

[0010] Technical means for solving problems

[0011] To address the aforementioned problems, the present invention provides a magnetic sensor, characterized in that it comprises: a magnetic detection unit that outputs a signal by applying a magnetic field; and a signal correction unit that corrects the signal output from the magnetic detection unit, wherein the magnetic detection unit includes a magnetoresistive element having a predetermined sensitivity axis, and the signal correction unit corrects the signal by using a correction value that reduces the distortion error contained in the signal output from the magnetic detection unit when the magnetic field is applied to the magnetoresistive element in a cross direction that is obliquely intersecting the sensitivity axis, thereby generating a correction signal.

[0012] In the magnetic sensor, the magnetic detection unit may also include a magnetoresistive element having the sensitivity axis on the first axis. Furthermore, the magnetoresistive element includes a first magnetoresistive element and a second magnetoresistive element. The sensitivity axis of the first magnetoresistive element is parallel to the first axis, and the sensitivity axis of the second magnetoresistive element is parallel to the second axis. The first axis and the second axis are orthogonal to each other, and the direction of intersection simply needs to be a direction that intersects at an angle relative to both the first axis and the second axis.

[0013] In the magnetic sensor, the signal correction unit can add the inverse distortion of the distortion error, which is the correction value, to the signal, or it can correct the signal using the following mathematical formula (1) to generate the correction signal.

[0014] V' = V + V 3 ×a…(1)

[0015] In the mathematical formula (1), V represents "the signal output from the magnetic detection unit", V' represents "the correction signal", and a represents "the correction coefficient".

[0016] The present invention provides an electrical control device, characterized in that it includes the magnetic sensor.

[0017] The present invention provides a calibration method for calibrating a signal output from a magnetic sensor including a magnetic detection unit, wherein the magnetic detection unit includes a magnetoresistive element having a defined sensitivity axis, and a signal is output by applying a magnetic field to the magnetoresistive element. The calibration method is characterized by comprising: a step of acquiring the signal output from the magnetic detection unit; and a step of calibrating the signal acquired in the step such that when the magnetic field is applied to the magnetoresistive element in a cross direction that is obliquely intersecting the sensitivity axis, the distortion error contained in the signal is reduced.

[0018] The present invention provides a method for manufacturing a magnetic sensor, the magnetic sensor including a magnetic detection unit and a signal correction unit, the magnetic detection unit including a magnetoresistive element having a predetermined sensitivity axis, the magnetoresistive element being subjected to a magnetic field to output a signal, and the signal correction unit correcting the signal output from the magnetic detection unit. The manufacturing method is characterized by comprising: a step of applying a test magnetic field to the magnetic detection unit in a direction intersecting the sensitivity axis of the magnetoresistive element; and a step of determining a correction value that reduces the distortion error contained in the test signal based on the test signal output from the magnetic detection unit corresponding to the application of the test magnetic field.

[0019] Invention Effects

[0020] According to the present invention, a magnetic sensor with good linearity of output signal regardless of the direction of the applied external magnetic field, an electrical control device using the magnetic sensor, a method for correcting the output signal of the magnetic sensor, and a method for manufacturing the magnetic sensor are provided. Attached Figure Description

[0021] Figure 1 This is a block diagram illustrating the schematic structure of a magnetic sensor according to an embodiment of the present invention.

[0022] Figure 2A This is a circuit diagram showing the schematic structure of the magnetic detection unit according to an embodiment of the present invention.

[0023] Figure 2B This is a circuit diagram showing a schematic structure of another embodiment of the magnetic detection unit of the present invention.

[0024] Figure 3 This is a perspective view showing the schematic structure of a magnetoresistive effect element according to an embodiment of the present invention.

[0025] Figure 4 This is a block diagram illustrating a schematic structure of another embodiment of the magnetic sensor according to the present invention.

[0026] Figure 5 This is a graph representing the results of Experiment Example 1.

[0027] Figure 6 This is a graph representing the results of Experiment Example 2.

[0028] Figure 7 This is a graph representing the results of Experiment Example 3.

[0029] Figure 8 This is a graph representing the results of Experiment Example 3. Detailed Implementation

[0030] The magnetic sensor according to an embodiment of the present invention will be described with reference to the accompanying drawings. Furthermore, in this embodiment, a current sensor is described as an example of a magnetic sensor, but the magnetic sensor of this embodiment is not limited to a current sensor.

[0031] In describing this embodiment, "first axis and second axis" are specified in several figures as needed. Here, the first axis is parallel to the sensitivity axis of the magnetoresistive effect element. The second axis is orthogonal to the first axis. Furthermore, in this specification and the figures, the first axis is sometimes referred to as the "X-axis" and the second axis as the "Y-axis". In this specification, "orthogonal" is a concept that includes not only the case where the two line segments, axes, directions, etc., that are objects intersect completely at 90°, but also the case where they are approximately orthogonal, that is, they intersect slightly off-center from 90° (within the range of 90° ± 5°). In addition, "parallel" is a concept that includes not only the case where the two line segments, axes, directions, etc., that are objects are completely parallel, but also the case where they are approximately parallel (within the range of 5° or less).

[0032] like Figure 1 As shown, the magnetic sensor 1 of this embodiment includes: a magnetic detection unit 2 that outputs a signal S by applying a magnetic field; and a signal processing unit 3 that processes the signal S output from the magnetic detection unit 2. The magnetic sensor 1 of this embodiment may be a magnetic sensor integrally formed and monolithically manufactured by combining the magnetic detection unit 2 and the signal processing unit 3, or a magnetic sensor formed by sealing the magnetic detection unit 2 and the signal processing unit 3 with resin and monolithically manufactured, or a magnetic sensor in which the magnetic detection unit 2 and the signal processing unit 3 are separately sealed with resin.

[0033] like Figure 2A and Figure 2B As shown, the magnetic detection unit 2 may include multiple component units 20 (e.g., first to fourth component units 21 to 24), but it may also include a single component unit 20. When multiple component units 20 are included, the magnetic detection unit 2 may also utilize a Wheatstone bridge circuit C formed by the multiple component units 20 (or a full-bridge circuit formed by the first to fourth component units 21 to 24, as shown in the figure). Figure 2A ) or a half-bridge circuit formed by the first element section 21 and the second element section 22 (see reference) Figure 2B ))constitute. Figure 2AThe Wheatstone bridge circuit C shown includes a power supply port V, a ground port G, two output ports E1 and E2, and first to fourth component sections 21 to 24. One end of each of the first component section 21 and the fourth component section 24 is connected to the power supply port V. The other end of the first component section 21 is connected to one end of the second component section 22 and the output port E1. The other end of the fourth component section 24 is connected to one end of the third component section 23 and the output port E2. The other ends of each of the second component section 22 and the third component section 23 are connected to the ground port G. A predetermined power supply voltage is applied to the power supply port V, and the ground port G is connected to ground.

[0034] In this embodiment, such as Figure 3 As shown, the component section 20 includes a plurality of magnetoresistive effect elements 40 connected in series. Each of the plurality of magnetoresistive effect elements 40 is, for example, a spin valve type magnetoresistive effect element. Furthermore, in this embodiment, the component section 20 connects the plurality of magnetoresistive effect elements 40, which are generally elliptical in shape when viewed from above, via a first lead electrode 51 and a second lead electrode 52 (see reference). Figure 3 ).

[0035] The spin valve type magnetoresistive element 40 includes an antiferromagnetic layer 41, a magnetized fixed layer 42, a non-magnetic layer 43, and a free layer 44 sequentially stacked on the substrate side (not shown). Figure 3 In the illustrated configuration, the free layer 44 is electrically connected to the first lead electrode 51, and the antiferromagnetic layer 41 is electrically connected to the second lead electrode 52. The antiferromagnetic layer 41, made of an antiferromagnetic material, generates exchange coupling with the magnetization fixing layer 42, thereby fixing the magnetization direction of the magnetization fixing layer 42. Furthermore, the magnetoresistive effect element 40 may also have a structure formed by sequentially stacking the free layer 44, the non-magnetic layer 43, the magnetization fixing layer 42, and the antiferromagnetic layer 41 from the substrate side. Alternatively, by setting the magnetization fixing layer 42 as a stacked ferrimagnetic layer / non-magnetic intermediate layer / ferromagnetic layer, and setting it as a so-called self-pinned fixing layer (SFP layer) formed by antiferromagnetic coupling of two ferromagnetic layers, the antiferromagnetic layer 41 can be omitted. Furthermore, in Figure 3In the illustrated configuration, the magnetoresistive element 40 may include a capping layer between the free layer 44 and the first lead electrode 51, or a base layer between the antiferromagnetic layer 41 and the second lead electrode 52. The spin-valve type magnetoresistive element 40 may be a TMR element or a GMR element. In the TMR element, the non-magnetic layer 43 is a tunnel barrier layer. In the GMR element, the non-magnetic layer 43 is a non-magnetic conductive layer. In the spin-valve type magnetoresistive element 40, the resistance value varies according to the angle formed by the magnetization direction of the free layer 44 relative to the magnetization direction of the magnetized fixed layer 42; the resistance value is minimum when the angle is 0° and maximum when the angle is 180°.

[0036] In this embodiment, the magnetization direction of the magnetization fixing layer 42 of the magnetoresistive effect element 40 is fixed to a direction parallel to the X-axis. Figure 2A In the illustrated configuration, the magnetization direction of the magnetization fixing layer 42 of the magnetoresistive effect element 40 in the first element section 21 and the third element section 23 is the "+X direction," while the magnetization direction of the magnetization fixing layer 42 of the magnetoresistive effect element 40 in the second element section 22 and the fourth element section 24 is the "-X direction." Furthermore, Figure 2A In the diagram, the magnetization direction of the magnetization fixing layer 42 of the magnetoresistive effect element 40 in the first to fourth element sections 21 to 24 is indicated by arrows. The magnetization direction of the magnetization fixing layer 42 of the magnetoresistive effect element 40 in the first to fourth element sections 21 to 24 is parallel to the minor axis direction or minor side direction of the magnetoresistive effect element 40, which is approximately elliptical or approximately rectangular in shape when viewed from above. That is, the sensitivity axis of the magnetoresistive effect element 40 in the first to fourth element sections 21 to 24 is parallel to the X-axis.

[0037] In this embodiment, the magnetization direction of the free layer 44 of the magnetoresistive element 40 in its initial state (the state before the magnetic field that is the target of detection is applied to the magnetic detection unit 2) is parallel to the Y-axis. Figure 2AIn the illustrated configuration, the easy magnetization axis direction of the free layer 44 of the magnetoresistive effect element 40 in the first element section 21 and the fourth element section 24 is the "-Y direction," while the easy magnetization axis direction of the free layer 44 of the magnetoresistive effect element 40 in the second element section 22 and the third element section 23 is the "+Y direction." In this embodiment, the easy magnetization axis direction of the free layer 44 of the magnetoresistive effect element 40 in the first to fourth element sections 21 to 24 is parallel to the major axis direction of the magnetoresistive effect element 40, which is approximately elliptical in top view. Alternatively, the easy magnetization axis direction of the free layer 44 of the magnetoresistive effect element 40 in the first to fourth element sections 21 to 24 may all be either the "+Y direction" or the "-Y direction." When the magnetoresistive element 40 is viewed from above and has a shape that is longer in the direction parallel to the Y direction, such as an approximately elliptical or approximately rectangular shape, the easy magnetization axis of the free layer 44 is easily set to the "+Y direction" or "-Y direction" due to the magnetic anisotropy of the shape. However, instead of the magnetic anisotropy of the shape, a bias magnetic field generating part such as a hard magnet (illustration omitted) can be provided to set the easy magnetization axis of the free layer 44 to the "+Y direction" or "-Y direction" by applying a bias magnetic field to the free layer 44.

[0038] In the magnetic detection unit 2, as the magnetic field is applied to each magnetoresistive effect element 40 of the first to fourth element units 21 to 24, the potential difference between the output ports E1 and E2 changes. The differential detector (not shown) outputs a signal S corresponding to the potential difference between the output ports E1 and E2 as a signal representing the magnetic field strength to the signal processing unit 3.

[0039] The signal processing unit 3 may include an A / D (analog-to-digital) converter 31 that converts the analog signal output from the magnetic detection unit 2 into a digital signal, and an arithmetic unit 32 that performs arithmetic processing on the digital signal that has been digitally converted by the A / D converter 31.

[0040] The signal S (analog signal) output from the magnetic detection unit 2 is converted into a digital signal by the A / D converter 31, and the digital signal is input to the arithmetic unit 32. The arithmetic unit 32 performs correction processing to correct the digital signal converted from the analog signal by the A / D converter 31, outputs a correction signal, or performs arithmetic processing based on the correction signal. The arithmetic unit 32 is, for example, a microcomputer, an ASIC (Application Specific Integrated Circuit), etc. In this embodiment, the arithmetic unit 32 or the signal processing unit 3 containing the arithmetic unit 32 constitutes a signal correction unit.

[0041] In the magnetic sensor 1 with the above-described structure, when a magnetic field parallel to the sensitivity axis (X-axis) of the magnetoresistive element 40 of the magnetic detection unit 2 is applied, the signal S output from the magnetic detection unit 2 does not actually contain distortion errors caused by higher harmonic components such as the third harmonic. Furthermore, "actually does not contain distortion errors" means that even if distortion errors are present in the signal S, they are contained to a degree that does not produce errors in the physical quantities, orientation, etc., obtained based on the signal S. On the other hand, when a magnetic field that intersects the sensitivity axis (X-axis) of the magnetoresistive element 40 at an angle greater than 0° and less than 90° relative to the X-axis (an inclined magnetic field) is applied, i.e., a magnetic field parallel to the XY plane, the signal S output from the magnetic detection unit 2 contains distortion errors caused by higher harmonic components such as the third harmonic. The distortion error contained in this signal S is a distortion error to a degree that produces unacceptable errors in the physical quantities, orientation, etc., obtained based on this signal S. Furthermore, the magnitude of the distortion error contained in signal S depends on the cross angle of the tilted magnetic field relative to the sensitivity axis (X-axis). Therefore, when the aforementioned tilted magnetic field is applied to the magnetoresistive element 40, the output signal from the magnetic sensor 1 will vary according to the angle of the tilted magnetic field relative to the sensitivity axis (X-axis), and the linearity of the output signal from the magnetic sensor 1 may deteriorate.

[0042] In the magnetic sensor 1 of this embodiment, even when the aforementioned tilted magnetic field is applied to the magnetoresistive element 40, the signal S output from the magnetic detection unit 2 is corrected by the arithmetic unit 32 of the signal processing unit 3, and a correction signal S' is output. Therefore, the linearity of the output signal from the magnetic sensor 1 can be well achieved.

[0043] The correction processing of signals in the arithmetic unit 32 will be explained.

[0044] The arithmetic unit 32 uses a predetermined correction value to correct the signal S output from the magnetic detection unit 2 and generates a correction signal S'.

[0045] The aforementioned correction value is a correction value that reduces the distortion error contained in the signal S when a magnetic field (a magnetic field parallel to the XY plane) that is obliquely intersecting the sensitivity axis (X-axis) of the magnetoresistive element 40 at an angle greater than 0° and less than 90° relative to the X-axis is applied to the magnetoresistive element 40. Specifically, the arithmetic unit 32 may, for example, correct the signal S using the following mathematical formula (1) and generate a correction signal S'.

[0046] V' = V + V 3 ×a…(1)

[0047] In the above mathematical formula (1), V represents "the signal S output from the magnetic detection unit 2", V' represents "the correction signal S'", and a represents "the correction coefficient (correction value)".

[0048] When the tilted magnetic field intersects the sensitivity axis (X-axis) of the magnetoresistive element 40 at a 45° angle, the distortion error contained in the signal S output from the magnetic detection unit 2 reaches its maximum value. Therefore, the "a" representing the correction coefficient in the above mathematical formula (1) is preferably set to a value that can reduce the distortion error contained in the signal S when a tilted magnetic field intersecting the sensitivity axis (X-axis) of the magnetoresistive element 40 at a 45° angle to the magnetoresistive element 40 is applied to the magnetoresistive element 40 to half. That is, the signal S is corrected by adding the anti-distortion caused by the third harmonic component in the same way as the distortion error contained in the signal S when a magnetic field parallel to the sensitivity axis (X-axis) is applied to the magnetoresistive element 40, and a correction signal S' is generated. A correction coefficient (correction value) is set to reduce the distortion error of the signal S when a 45° inclined magnetic field is applied to the magnetoresistive element 40 to half. A correction signal S' is generated using the aforementioned mathematical formula (1). Thus, regardless of the angle at which the magnetic field applied to the magnetoresistive element 40 intersects with the sensitivity axis (X-axis) of the magnetoresistive element 40, the distortion error of the signal S can be stabilized. Therefore, regardless of the angle of the magnetic field applied to the magnetoresistive element 40 with respect to the sensitivity axis (X-axis), the linearity of the output signal from the magnetic sensor 1 can be well maintained. Furthermore, when correcting the signal S by adding the anti-distortion caused by the third harmonic component, it is preferable that the distortion error contained in the signal S when a magnetic field parallel to the sensitivity axis (X-axis) is applied to the magnetoresistive element 40 is the same as the distortion error contained in the signal S when a magnetic field intersecting the sensitivity axis (X-axis) at 45° is applied to the magnetoresistive element 40. However, it is also possible to correct the signal S by adding the anti-distortion caused by the third harmonic component in a way that at least the distortion error contained in the signal S when a magnetic field intersecting the sensitivity axis (X-axis) is applied to the magnetoresistive element 40 is reduced.

[0049] like Figure 4As shown, the magnetic sensor 1 of this embodiment may also include a magnetic detection unit 2 comprising a first magnetic detection unit 2A and a second magnetic detection unit 2B, and a signal processing unit 3. The first magnetic detection unit 2A only needs to have a first magnetoresistive element 40 with its sensitivity axis parallel to the X-axis, and the second magnetic detection unit 2B only needs to have a second magnetoresistive element 40 with its sensitivity axis parallel to the Y-axis. The first magnetic detection unit 2A is used to detect a magnetic field parallel to the X-axis, and the second magnetic detection unit 2B is used to detect a magnetic field parallel to the Y-axis. When a magnetic field that intersects at an angle relative to both the X-axis and Y-axis is applied to the magnetoresistive elements 40 of the first magnetic detection unit 2A and the second magnetic detection unit 2B, the distortion errors contained in the signals S output from each of the first magnetic detection unit 2A and the second magnetic detection unit 2B will overlap, potentially further deteriorating the linearity of the output signal from the magnetic sensor 1. The magnetic sensor 1 of this embodiment can reduce the distortion error of the signal S output from each of the first magnetic detection unit 2A and the second magnetic detection unit 2B by applying a tilted magnetic field, and correct the signal S to generate a correction signal S'. Therefore, regardless of the angle of the magnetic field applied to the magnetoresistive effect element 40 relative to the sensitivity axis, the linearity of the output signal from the magnetic sensor 1 can be good.

[0050] The magnetic sensor 1 of this embodiment can be manufactured, for example, as follows.

[0051] First, a first lead electrode 51, a second lead electrode 52, and a magnetoresistive effect element 40 are formed on a substrate. When forming the magnetoresistive effect element 40, the magnetization fixing layer 42 is magnetized and fixed in a direction parallel to the minor axis direction of the magnetoresistive effect element 40, which is approximately elliptical in shape when viewed from above.

[0052] Next, a test magnetic field is applied to the magnetoresistive element 40 at a 45° angle to the sensitivity axis (magnetization direction of the magnetization fixing layer 42) of the magnetoresistive element 40, and a test signal output from the magnetic detection unit 2 is acquired corresponding to the application of the test magnetic field. This test signal contains distortion error caused by the third harmonic component due to the application of the tilted magnetic field. Therefore, a correction coefficient (correction value) capable of reducing this distortion error to half is obtained. Then, a signal processing unit 3 is fabricated to store the obtained correction coefficient (correction value). Thus, the magnetic sensor 1 of this embodiment can be manufactured.

[0053] The magnetic sensor 1 of this embodiment can be installed in an electronic control device. Furthermore, examples of electronic control devices for this embodiment include magnetic field strength sensors, gaussmeters, electronic compasses, and linear encoders. As described above, the magnetic sensor 1 of this embodiment can output a signal with good linearity regardless of the angle of the magnetic field applied to the magnetoresistive element 40 relative to the sensitivity axis. Therefore, the magnetic sensor 1 of this embodiment is particularly useful as a sensor for detecting orientation in an electronic compass used in an environment where a 360° magnetic field can be applied in the XY plane.

[0054] The embodiments described above are provided for ease of understanding of the present invention and are not intended to limit the scope of the invention. Therefore, the elements disclosed in the above embodiments also include all design modifications and equivalents that fall within the technical scope of the present invention. Furthermore, the dimensions and designs of the elements disclosed in the above embodiments are examples and are not intended to limit the invention.

[0055]

Example

[0056] The present invention will be described in more detail below with examples, but the present invention is not limited by the examples described below.

[0057] [Experimental Example 1]

[0058] Incorporating a magnetoresistive element 40 (reference) Figure 3 Magnetic detection unit 2 (refer to) Figure 2A ) of, having Figure 1 In the magnetic sensor 1 shown, the signal S output from the magnetic detection unit 2 is obtained by simulation when a magnetic field parallel to the sensitivity axis (X-axis) of the magnetoresistive element 40 is applied. The result is then... Figure 5 As shown in [the image]. Furthermore, in [the image]... Figure 5 In the graph shown, the horizontal axis represents the standardized magnetic field strength applied to the magnetoresistive element 40, and the vertical axis represents the output (Vout) of the magnetoresistive element 40 and the distortion error (Delta) caused by the third harmonic component. As a result, the signal S does not contain the distortion error caused by the third harmonic component (Delta = 0), exhibiting good linearity (see reference). Figure 5 ).

[0059] [Experimental Example 2]

[0060] In the magnetic sensor 1 of Experimental Example 1, the signal S output from the magnetic detection unit 2 was obtained by simulation when a magnetic field intersecting the sensitivity axis (X-axis) of the magnetoresistive element 40 at a 45° angle was applied. The results were then... Figure 6 As shown in [the image]. Furthermore, in [the image]... Figure 6In the graph shown, the horizontal axis represents the standardized magnetic field strength applied to the magnetoresistive element 40, and the vertical axis represents the output (Vout) of the magnetoresistive element 40 and the distortion error (Delta) caused by the third harmonic component. As a result, the signal S contains distortion error caused by the third harmonic component, and its linearity deteriorates compared to the signal S obtained in Experimental Example 1 (see reference). Figure 6 ).

[0061] [Experimental Example 3]

[0062] To obtain a correction coefficient (correction value) that reduces the distortion error in the signal S obtained in Experimental Example 2 to half, the signal S obtained in Experimental Example 1 is corrected using the above mathematical formula (1), and the corrected signal S' is obtained. Similarly, the signal S obtained in Experimental Example 2 is corrected, and the corrected signal S' is obtained. The results are then... Figure 7 and Figure 8 As shown in [the image]. Furthermore, in [the image]... Figure 7 and Figure 8 In the chart shown, the horizontal axis represents the standardized magnetic field strength applied to the magnetoresistive element 40, and the vertical axis represents the output (Vout) of the magnetoresistive element 40 and the distortion error (Delta) caused by the third harmonic component.

[0063] As a result, the distortion error caused by the third harmonic component in the corrected signal S' obtained from the signal S obtained in Experimental Example 1 was corrected, and the distortion error caused by the third harmonic component in the corrected signal S' obtained from the signal S obtained in Experimental Example 2 was corrected (refer to...). Figure 7 However, the corrected signal S' obtained by correcting the signal S obtained in Experimental Example 2 exhibits better linearity than the signal S obtained in Experimental Example 2 (see [reference]). Figure 8 ).

[0064] Find the maximum value MAX of the distortion error Er1 contained in the signal S obtained in Experiment Example 1. Er1 (=0) and the maximum value of the distortion error Er2 contained in the signal S obtained in Experimental Example 2, MAX Er2 The difference (MAX) Er1 -MAX Er2 The absolute value of ABS and the maximum value of the distortion error Er1' contained in the corrected signal S' obtained by correcting the signal S obtained in Experimental Example 1. Er1’ And the maximum value MAX of the distortion error Er2' contained in the corrected signal S' obtained by correcting the signal S obtained in Experimental Example 2. Er2’ The difference (MAX) Er1’ -MAX Er2’The absolute value of ABS' was compared between the two. The result showed that the absolute value ABS' was 0.003% of the absolute value ABS. Based on this result, it was determined that by applying a tilted magnetic field to the magnetoresistive element 40, preferably at a 45° angle relative to the sensitivity axis (X-axis), a correction value (correction coefficient a) can reduce the distortion error contained in the signal S output from the magnetic detection unit 2. Regardless of the angle of the magnetic field applied to the magnetoresistive element 40 relative to the sensitivity axis, the linearity of the output signal from the magnetic sensor 1 can be well maintained.

[0065] Explanation of reference numerals in the attached figures

[0066] 1…Magnetic sensor

[0067] 2…Magnetic Detection Department

[0068] 2A…First Magnetic Detection Department

[0069] 2B…Second Magnetic Detection Section

[0070] 21…First Component Section

[0071] 22…Second Component Section

[0072] 23…Third Component Section

[0073] 24…Fourth Component Section

[0074] 3…Signal Processing Department

[0075] 32…Arithmetic Unit

[0076] 40…Magnetoresistive element

[0077] 42…Magnetic fixing layer

[0078] 44… Free Layer

Claims

1. A magnetic sensor, characterized in that, include: The magnetic detection unit outputs a signal by applying a magnetic field; and A signal correction unit that corrects the signal output from the magnetic detection unit. The magnetic detection unit includes a magnetoresistive element with a defined sensitivity axis. The signal correction unit, Receive the signal output from the magnetic detection unit. A correction signal is generated by using a correction value that reduces the distortion error in the signal output from the magnetic detection unit when the magnetic field with a specific value is applied to the magnetoresistive effect element in an oblique direction relative to the sensitivity axis.

2. The magnetic sensor according to claim 1, characterized in that, The magnetic detection unit includes the magnetoresistive effect element having the sensitivity axis on the first axis.

3. The magnetic sensor according to claim 1, characterized in that, The magnetoresistive element includes a first magnetoresistive element and a second magnetoresistive element. The sensitivity axis of the first magnetoresistive element is parallel to the first axis. The sensitivity axis of the second magnetoresistive element is parallel to the second axis. The first axis and the second axis are orthogonal to each other. The intersection direction is a direction that intersects at an angle relative to both the first axis and the second axis.

4. The magnetic sensor according to any one of claims 1 to 3, characterized in that, The signal correction unit adds the inverse distortion of the distortion error, which serves as the correction value, to the signal.

5. The magnetic sensor according to any one of claims 1 to 3, characterized in that, The signal correction unit corrects the signal using the following mathematical formula (1) to generate the corrected signal. V’ = V + V 3 × a …(1), In the mathematical formula (1), V represents the signal output from the magnetic detection unit, V' represents the correction signal, and a represents the correction coefficient.

6. An electrical control device, characterized in that, The magnetic sensor includes any one of claims 1 to 3.

7. A calibration method for calibrating a signal output from a magnetic detection unit in a magnetic sensor including a magnetic detection unit, wherein, The magnetic detection unit includes a magnetoresistive element with a defined sensitivity axis, through which a magnetic field is applied to output a signal. The correction method is characterized by comprising: A process for acquiring the signal output from the magnetic detection unit; The process of calculating the correction value that reduces the distortion error contained in the signal when the magnetic field, having a specific value and intersecting in a cross direction obliquely relative to the sensitivity axis, is applied to the magnetoresistive element; and The process of using the correction value to correct the signal acquired in the process.

8. A method for manufacturing a magnetic sensor, the magnetic sensor comprising a magnetic detection unit and a signal correction unit, the magnetic detection unit including a magnetoresistive element having a predetermined sensitivity axis, the magnetoresistive element being subjected to a magnetic field to output a signal, and the signal correction unit correcting the signal output from the magnetic detection unit, the method for manufacturing the magnetic sensor being characterized in that it comprises: A process of applying a test magnetic field of a specific value to the magnetic detection unit in a direction intersecting the sensitivity axis of the magnetoresistive element; and A process for determining a correction value that reduces the distortion error contained in the test signal based on the test signal output from the magnetic detection unit corresponding to the application of the test magnetic field.

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