Magnetic sensor, its manufacturing method and design method, and motor device

Abstract

Generates detection signals that can be used for motor rotation control. [Solution] The magnetic sensor 1 comprises a first bridge circuit 11 including first to fourth resistance sections R11 to R14, and a second bridge circuit 12 including first to fourth resistance sections R21 to R24. The average direction of the magnetization directions of the multiple magnetization fixed layers 52 is the first to fourth magnetization directions m11 to m14 for the first to fourth resistance sections R11 to R14, and the first to fourth magnetization directions m21 to m24 for the first to fourth resistance sections R21 to R24, respectively. In the first to fourth resistance sections R11 to R14, the three magnetization directions corresponding to the three resistance sections intersect each other at angles other than 0° and 180°. In the first to fourth resistance sections R21 to R24, the three magnetization directions corresponding to the three resistance sections intersect each other at angles other than 0° and 180°.

Description

Technical Field

[0001] The present disclosure relates to a magnetic sensor configured to detect the rotation angle of a motor, a manufacturing method and a design method thereof, and a motor device including the motor and the magnetic sensor.

Background Art

[0002] In a brushless motor (also referred to as a brushless DC motor), an angle detector is used to detect the rotation angle of the brushless motor. As the angle detector, a detector using a magnetic detection element such as a Hall element or an optical detector using light is known. The detection signal of the angle detector is used for feedback control of the rotation angle and rotation speed of the brushless motor.

[0003] A brushless motor is generally a three-phase motor driven by a three-phase AC voltage. The three-phase motor includes a plurality of coils that are controlled so that voltages are applied at different timings from each other. When the three-phase motor includes three coils, it is possible to control the timing of voltage application using three logic signals (signals representing two states of "High" and "Low") having phases different by 120° each. The detection signal of the angle detector is used to generate the three logic signals. When generating the three logic signals by an angle detector using a Hall element, it is necessary to arrange Hall elements at three locations in the brushless motor.

[0004] By the way, as the magnetic detection element, in addition to the Hall element, a spin valve type magnetoresistive effect element is known. The spin valve type magnetoresistive effect element has a magnetization fixed layer having a magnetization with a fixed direction, a free layer having a magnetization whose direction can change according to the direction of an applied magnetic field, and a gap layer disposed between the magnetization fixed layer and the free layer.

[0005] Patent documents 1, 2, and 3 disclose magnetic sensors using spin valve type magnetoresistive elements. Patent document 1 also discloses a magnetoresistive Wheatstone bridge including a plurality of resistors with pinning directions set in different directions from each other. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2016 / 083420 [Patent Document 2] Japanese Patent Publication No. 2022-111711 [Patent Document 3] Japanese Patent Publication No. 2013-88232 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Here, we consider the case where a magnetic sensor using a spin valve type magnetoresistive element is used for motor rotation control. In this case, it is conceivable to configure the magnetic sensor to generate two detection signals with different phases, and then use these two detection signals to generate three logic signals. When the direction of the magnetic field detected by the magnetic sensor changes at a predetermined angular velocity, the waveforms of the two detection signals will ideally be sinusoidal (including sine and cosine waveforms). However, when a magnetic sensor is placed inside a brushless motor, the waveforms of the two detection signals may be significantly distorted from a sinusoidal curve. In this case, it is not possible to generate three logic signals with a predetermined phase difference.

[0008] This disclosure has been made in view of the aforementioned problems, and its purpose is to provide a magnetic sensor capable of generating a detection signal usable for motor rotation control, a method for manufacturing and designing the same, and a motor device equipped with this magnetic sensor. [Means for solving the problem]

[0009] The magnetic sensor of this disclosure comprises at least one bridge circuit and a plurality of magnetoresistive elements. The at least one bridge circuit includes a first port, a second port, a third port, a fourth port, a first resistive section provided between the first port and the second port, a second resistive section provided between the second port and the third port, a third resistive section provided between the third port and the fourth port, and a fourth resistive section provided between the fourth port and the first port. Each of the plurality of magnetoresistive elements includes a magnetization-fixed layer having a magnetization with a fixed direction and a free layer having a magnetization with a direction that can change depending on the applied magnetic field. The plurality of magnetoresistive elements include a plurality of first magnetoresistive elements constituting a first resistive section, a plurality of second magnetoresistive elements constituting a second resistive section, a plurality of third magnetoresistive elements constituting a third resistive section, and a plurality of fourth magnetoresistive elements constituting a fourth resistive section. The first, second, and third resistive sections are configured such that a first magnetization direction, which is the average direction of the magnetization directions of multiple magnetization fixed layers included in a plurality of first magnetoresistive elements, a second magnetization direction, which is the average direction of the magnetization directions of multiple magnetization fixed layers included in a plurality of second magnetoresistive elements, and a third magnetization direction, which is the average direction of the magnetization directions of multiple magnetization fixed layers included in a plurality of third magnetoresistive elements, intersect each other at angles other than 0° and 180°.

[0010] The motor device of this disclosure comprises a motor, a motor drive circuit, and a magnetic sensor of this disclosure. The magnetic sensor is connected to the drive circuit.

[0011] The method for manufacturing a magnetic sensor according to this disclosure includes an element formation step for forming a plurality of magnetoresistive elements. The element formation step includes a step of forming a laminated film including a plurality of first magnetic parts which will later become a plurality of magnetization fixed layers and a plurality of second magnetic parts which will later become a plurality of free layers, and a fixing step of fixing the magnetization direction of each of the plurality of first magnetic parts using laser light and an external magnetic field. The fixing step includes a first step of fixing the magnetization direction of a plurality of specific first magnetic parts which will later become a plurality of magnetization fixed layers of a plurality of first magnetoresistive elements, a second step of fixing the magnetization direction of a plurality of specific second magnetic parts which will later become a plurality of magnetization fixed layers of a plurality of second magnetoresistive elements, and a third step of fixing the magnetization direction of a plurality of specific third magnetic parts which will later become a plurality of magnetization fixed layers of a plurality of third magnetoresistive elements. The directions of the external magnetic field in the first process, the second process, and the third process intersect each other at angles other than 0° and 180°.

[0012] A magnetic sensor designed by the design method of the present disclosure comprises a bridge circuit and a plurality of magnetoresistive elements. The bridge circuit includes a first port, a second port, a third port, a fourth port, a first resistive section between the first port and the second port, a second resistive section between the second port and the third port, a third resistive section between the third port and the fourth port, and a fourth resistive section between the fourth port and the first port. Each of the plurality of magnetoresistive elements includes a magnetization-fixed layer having a magnetization with a fixed direction and a free layer having a magnetization with a direction changeable in response to an applied magnetic field. The plurality of magnetoresistive elements include a plurality of first magnetoresistive elements constituting a first resistive section, a plurality of second magnetoresistive elements constituting a second resistive section, a plurality of third magnetoresistive elements constituting a third resistive section, and a plurality of fourth magnetoresistive elements constituting a fourth resistive section. The bridge circuit is configured to detect a rotating magnetic field whose direction is rotating at the detection location.

[0013] The design method of the present disclosure includes setting the magnetization directions of a plurality of magnetization stationary layers contained in each of a plurality of first magnetoresistive elements, a plurality of second magnetoresistive elements, a plurality of third magnetoresistive elements, and a plurality of fourth magnetoresistive elements, such that the bridge circuit generates a first detection signal and a second detection signal corresponding to a change in the direction of a rotating magnetic field, respectively, and setting the magnetization directions of the plurality of magnetization stationary layers such that a temporal interval corresponding to one rotation of the direction of the rotating magnetic field is divided into three or more temporal sub-intervals based on the first detection signal and the second detection signal. [Effects of the Invention]

[0014] In this disclosure, the first magnetization direction, the second magnetization direction, and the third magnetization direction intersect each other at angles other than 0° and 180°. This has the effect of enabling a magnetic sensor that can generate a detection signal usable for motor rotation control. [Brief explanation of the drawing]

[0015] [Figure 1] This is an explanatory diagram showing the configuration of a motor device according to the first embodiment of this disclosure. [Figure 2] This is a plan view showing a part of a motor device according to the first embodiment of this disclosure. [Figure 3] This is an explanatory diagram showing the inside of a magnetic sensor according to the first embodiment of the present disclosure. [Figure 4] This is a circuit diagram showing the circuit configuration of a magnetic sensor according to the first embodiment of this disclosure. [Figure 5] This is an explanatory diagram illustrating the definitions of direction and angle in the first embodiment of the present disclosure. [Figure 6] This is a perspective view showing a portion of the resistor in the first embodiment of the present disclosure. [Figure 7] This is a waveform diagram showing the waveforms of the first and second detection signals in the first embodiment of the present disclosure. [Figure 8]A timing chart showing the first to third logic signals in the first embodiment of the present disclosure. [Figure 9] A flowchart showing a method for manufacturing a magnetic sensor according to the first embodiment of the present disclosure. [Figure 10] A flowchart showing a design method for a magnetic sensor according to the first embodiment of the present disclosure. [Figure 11] A circuit diagram showing the circuit configuration of a magnetic sensor of a comparative example. [Figure 12] A waveform diagram showing the waveforms of each of the first and second detection signals of a comparative example. [Figure 13] A waveform diagram showing the waveforms of each of the first and second detection signals in a first modification of the magnetic sensor according to the first embodiment of the present disclosure. [Figure 14] A waveform diagram showing the waveforms of each of the first and second detection signals in a second modification of the magnetic sensor according to the first embodiment of the present disclosure. [Figure 15] A waveform diagram showing the waveforms of each of the first and second detection signals in a third modification of the magnetic sensor according to the first embodiment of the present disclosure. [Figure 16] A circuit diagram showing the circuit configuration of a magnetic sensor according to the second embodiment of the present disclosure. [Figure 17] A waveform diagram showing the waveforms of each of the first and second detection signals in the second embodiment of the present disclosure.

Embodiments for Carrying Out the Invention

[0016] [First Embodiment] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. First, referring to FIGS. 1 and 2, a schematic configuration of a motor device according to the first embodiment of the present disclosure will be described. FIG. 1 is an explanatory diagram showing the configuration of a motor device 100 according to the present embodiment. FIG. 2 is a plan view showing a part of the motor device 100.

[0017] The motor device 100 according to this embodiment comprises a magnetic sensor 1 according to this embodiment, a motor 70, and a drive circuit 120 for driving the motor 70. The motor 70 is, for example, a three-phase brushless motor (also called a brushless DC motor). The following explanation will take the case where the motor 70 is a three-phase brushless motor as an example. In this case, the motor 70 includes a shaft (not shown) configured to rotate around a rotation axis C, a rotor 71 (not shown) fixed to the shaft, a stator 72, and a plurality of coils.

[0018] Figure 1 shows an example where the stator 72 has three slots. In this example, the motor 70 includes a number of coils: a first coil 73u, a second coil 73v, and a third coil 73w. The first coil 73u, the second coil 73v, and the third coil 73w are also called the U-phase coil, V-phase coil, and W-phase coil, respectively. The first coil 73u, the second coil 73v, and the third coil 73w are arranged at 120° intervals around the rotation axis C.

[0019] The rotor 71 is composed of a magnetic field generator 74 that generates a magnetic field. Figures 1 and 2 show a multipole magnet as an example of a magnetic field generator 74, in which one or more pairs of north poles and south poles are arranged alternately in a ring shape. In the example shown in Figures 1 and 2, the magnetic field generator 74 is a four-pole magnet containing two pairs of north poles and south poles.

[0020] Furthermore, the number of slots in the stator 72 is not limited to three, but may be a number greater than three, such as six or nine. Also, the magnetic field generator 74 may be a cylindrical two-pole magnet having a north pole and a south pole arranged symmetrically around a virtual plane containing the rotation axis C. If the magnetic field generator 74 is a multi-pole magnet, the number of poles of the magnetic field generator 74 is not limited to four, but may be eight.

[0021] The direction of the magnetic field generated by the magnetic field generator 74 rotates in conjunction with the rotation of the motor 70, i.e., the rotation of a shaft not shown. Hereinafter, the magnetic field generated by the magnetic field generator 74 will be referred to as the rotating magnetic field MF. The rotating magnetic field MF is shown in Figure 5, which will be explained later. When n is an integer of 1 or more, if the magnetic field generator is a 2n-pole magnet, the rotating magnetic field MF rotates n times while the rotor 71 rotates once. The magnetic sensor 1 is configured to detect the rotating magnetic field MF and generate three logic signals used to control the timing of the voltages applied to the first to third coils 73u, 73v, and 73w. In this embodiment, the magnetic sensor 1 is located away from the rotation axis C. For example, the magnetic sensor 1 is located outside the outer surface of the magnetic field generator 74. The configuration of the magnetic sensor 1 will be explained in detail later.

[0022] The drive circuit 120 includes a control circuit 121 and an output circuit 122. The control circuit 121 is configured to receive three logic signals generated by the magnetic sensor 1 and an external speed command Sc. The control circuit 121 controls the output circuit 122 based on the three logic signals and the speed command Sc. The output circuit 122 applies voltage to the first to third coils 73u, 73v, and 73w, respectively, according to the command from the control circuit 121.

[0023] The output circuit 122 includes six switching elements (not shown). Each of the six switching elements is, for example, a transistor. The control circuit 121 controls the timing at which voltage is applied to each of the first to third coils 73u, 73v, and 73w, so that the combined magnetic field (hereinafter referred to as the combined magnetic field) generated from the magnetic fields generated by the first to third coils 73u, 73v, and 73w rotates by controlling the ON and OFF states of the six switching elements. This timing is controlled based on three logic signals. The rotor 71 rotates due to the interaction between the magnetic field generated by the magnetic field generator 74 (rotating magnetic field MF) and the combined magnetic field.

[0024] Furthermore, the control circuit 121 compares the speed command Sc with the rotational speed of the motor 70 obtained from the three logic signals, and controls the output circuit 122 so that the rotational speed of the motor 70 follows the speed command Sc.

[0025] Next, the magnetic sensor 1 will be described in detail with reference to Figures 3 and 4. Figure 3 is an explanatory diagram showing the inside of the magnetic sensor 1. Figure 4 is a circuit diagram showing the circuit configuration of the magnetic sensor 1.

[0026] First, the configuration of the magnetic sensor 1 will be outlined. As mentioned above, the magnetic sensor 1 is used in the drive circuit 120 of the motor 70. The magnetic sensor 1 comprises a detection circuit 10 and a logic signal generation circuit 20. Each of the detection circuit 10 and the logic signal generation circuit 20 may have the form of a rectangular parallelepiped chip. Hereinafter, the chip containing the detection circuit 10 will be referred to as the first chip 3, and the chip containing the logic signal generation circuit 20 will be referred to as the second chip 4. The magnetic sensor 1 comprises the first chip 3 and the second chip 4.

[0027] As shown in Figure 3, one of the first chip 3 and the second chip 4 is mounted on top of the other. The magnetic sensor 1 further includes a substrate 5. In this embodiment in particular, the second chip 4 is mounted on the substrate 5, and the first chip 3 is mounted on top of the second chip 4.

[0028] The magnetic sensor 1 further comprises a plurality of wires 41, 42 and a plurality of leads 43. The plurality of wires 41 connect the first chip 3 and the second chip 4. The plurality of wires 42 connect the second chip 4 and the plurality of leads 43.

[0029] The magnetic sensor 1 further comprises a body 2 that incorporates a first chip 3 and a second chip 4. The body 2 includes a sealing resin 44 that seals the first chip 3 and the second chip 4. Multiple leads 43 extend outward from the sealing resin 44.

[0030] The logic signal generation circuit 20 (second chip 4) does not necessarily have to be built into the main unit 2. In this case, the logic signal generation circuit 20 may be located in a different position from the main unit 2.

[0031] Next, the configuration of the detection circuit 10 will be described. The detection circuit 10 is configured to detect a physical quantity that changes periodically in conjunction with the rotation angle of the motor 70 and to output a first detection signal S1 and a second detection signal S2. In this embodiment, the physical quantity is the rotating magnetic field MF generated by the magnetic field generator 74. The direction of the rotating magnetic field MF rotates in conjunction with the rotation angle of the motor 70.

[0032] Here, the definitions of direction and angle in this embodiment will be explained with reference to Figures 1, 3, and 5. Figure 5 is an explanatory diagram showing the definitions of direction and angle in this embodiment. First, the direction parallel to the rotation axis C shown in Figure 1 is defined as the Z direction. In Figure 3, the Z direction is represented as the direction pointing upwards, and in Figure 5, the Z direction is represented as the direction pointing from back to front in Figure 5. As shown in Figure 3, the first chip 3 (detection circuit 10) and the second chip 4 (logic signal generation circuit 20) are stacked in the Z direction.

[0033] Next, the two directions perpendicular to the Z direction and orthogonal to each other are defined as the X and Y directions. In Figures 3 and 5, the X direction is represented as the direction moving to the right. In Figure 3, the Y direction is represented as the direction moving from the foreground to the background in Figure 3, and in Figure 5, the Y direction is represented as the direction moving upwards. Furthermore, the direction opposite to the X direction is defined as the -X direction, the direction opposite to the Y direction is defined as the -Y direction, and the direction opposite to the Z direction is defined as the -Z direction.

[0034] In Figure 5, the symbol PL represents a virtual plane perpendicular to the rotation axis C. Hereinafter, this virtual plane will be referred to as the reference plane PL. In this embodiment, the detection circuit 10 is configured to detect the component of the rotating magnetic field MF at the reference position PR within the reference plane PL that is parallel to the reference plane PL. In the following description, the direction of the rotating magnetic field MF refers to the direction located within the reference plane PL. The reference position PR is located away from the rotation axis C (for example, the position where the magnetic sensor 1 is placed).

[0035] In Figure 5, the direction of the rotating magnetic field MF is indicated by an arrow denoted with the symbol MF. In this embodiment, the direction of the rotating magnetic field MF is expressed by the angle θ it makes with respect to the reference direction DR (hereinafter referred to as the rotating magnetic field angle). The reference direction DR is the X direction. The direction of the rotating magnetic field MF is assumed to be counterclockwise in Figure 5. The rotating magnetic field angle θ is expressed as a positive value when viewed counterclockwise from the reference direction DR, and as a negative value when viewed clockwise from the reference direction DR.

[0036] The detection circuit 10 includes at least one bridge circuit and a plurality of magnetoresistive elements (hereinafter referred to as MR elements) 50. The at least one bridge circuit includes a plurality of resistive sections composed of the plurality of MR elements 50. The at least one bridge circuit may be a Wheatstone bridge circuit (full bridge circuit) including four resistive sections, or a circuit consisting of two half-bridge circuits, each including two resistive sections. The at least one bridge circuit further includes four ports. Each of the four resistive sections is located between any two of the four ports.

[0037] In this embodiment, the detection circuit 10 specifically includes at least one bridge circuit, namely a first bridge circuit 11 and a second bridge circuit 12. The first and second bridge circuits 11 and 12 are each Wheatstone bridge circuits.

[0038] The first bridge circuit 11 includes a power port V1, a ground port G1, a first output port E11, a second output port E12, a first resistor R11, a second resistor R12, a third resistor R13, and a fourth resistor R14. The first resistor R11 is located between the power port V1 and the first output port E11 in the circuit configuration. The second resistor R12 is located between the ground port G1 and the first output port E11 in the circuit configuration. The third resistor R13 is located between the ground port G1 and the second output port E12 in the circuit configuration. The fourth resistor R14 is located between the power port V1 and the second output port E12 in the circuit configuration. In this application, the expression "in the circuit configuration" refers to the arrangement on the circuit diagram, not the arrangement in the physical configuration.

[0039] The second bridge circuit 12 includes a power port V2, a ground port G2, a first output port E21, a second output port E22, a first resistor R21, a second resistor R22, a third resistor R23, and a fourth resistor R24. The first resistor R21 is located between the power port V2 and the first output port E21 in the circuit configuration. The second resistor R22 is located between the ground port G2 and the first output port E21 in the circuit configuration. The third resistor R23 is located between the ground port G2 and the second output port E22 in the circuit configuration. The fourth resistor R24 ​​is located between the power port V2 and the second output port E22 in the circuit configuration.

[0040] The detection circuit 10 further includes power terminals 10a1, 10a2, ground terminals 10b1, 10b2, a first output terminal 10c, a second output terminal 10d, a first differential amplifier 13, and a second differential amplifier 14.

[0041] Power ports V1 and V2 are connected to power terminals 10a1 and 10a2, respectively. Ground ports G1 and G2 are connected to ground terminals 10b1 and 10b2, respectively. A predetermined voltage or current is applied to each of the power terminals 10a1 and 10a2. Each of the ground terminals 10b1 and 10b2 is connected to ground.

[0042] The first differential amplifier 13 has two input terminals and one output terminal. The first and second output ports E11 and E12 are connected to the two input terminals of the first differential amplifier 13. The output terminal of the first differential amplifier 13 is connected to the first output terminal 10c. The first differential amplifier 13 generates a signal corresponding to the potential difference between the first and second output ports E11 and E12 as the first detection signal S1. The first output terminal 10c outputs the first detection signal S1.

[0043] The second differential amplifier 14 has two input terminals and one output terminal. The first and second output ports E21 and E22 are connected to the two input terminals of the second differential amplifier 14. The output terminal of the second differential amplifier 14 is connected to the second output terminal 10d. The second differential amplifier 14 generates a signal corresponding to the potential difference between the first and second output ports E21 and E22 as the second detection signal S2. The second output terminal 10d outputs the second detection signal S2.

[0044] Here, the MR element 50 will be described in detail. In this embodiment, the MR element 50 is a spin-valve type MR element. The spin-valve type MR element includes a magnetization fixed layer having magnetization with a fixed direction, a free layer which is a magnetic layer having magnetization whose direction can be changed according to a rotating magnetic field MF, and a gap layer disposed between the magnetization fixed layer and the free layer. The spin-valve type MR element may be a TMR (tunnel magnetoresistance) element or a GMR (giant magnetoresistance) element. In a TMR element, the gap layer is a tunnel barrier layer. In a GMR element, the gap layer is a non-magnetic conductive layer. In a spin-valve type MR element, the resistance value changes according to the angle that the direction of magnetization of the free layer makes with respect to the direction of magnetization of the magnetization fixed layer. The resistance value is at its minimum when this angle is 0° and at its maximum when the angle is 180°.

[0045] Figure 6 is a perspective view showing a portion of any of the resistors R11-R14 and R21-R24. Any resistor includes a plurality of lower electrodes 61, a plurality of MR elements 50, and a plurality of upper electrodes 62. The plurality of lower electrodes 61 are arranged on a substrate (not shown). Each lower electrode 61 has an elongated shape. A gap is formed between two adjacent lower electrodes 61 in the longitudinal direction. As shown in Figure 6, the MR elements 50 are arranged near both ends in the longitudinal direction on the upper surface of the lower electrodes 61.

[0046] The MR element 50 includes an antiferromagnetic layer 51, a magnetization-fixing layer 52, a gap layer 53, and a free layer 54, stacked in order from the lower electrode 61 side. The antiferromagnetic layer 51 is electrically connected to the lower electrode 61. The antiferromagnetic layer 51 is made of an antiferromagnetic material and creates exchange coupling with the magnetization-fixing layer 52, fixing the direction of magnetization of the magnetization-fixing layer 52. Multiple upper electrodes 62 are arranged on top of multiple MR elements 50. Each upper electrode 62 has an elongated shape and is placed on two lower electrodes 61 adjacent to each other in the longitudinal direction of the lower electrode 61, electrically connecting the free layers 54 of two adjacent MR elements 50. With this configuration, any resistor shown in Figure 6 includes multiple MR elements 50 connected in series by multiple lower electrodes 61 and multiple upper electrodes 62.

[0047] The magnetization fixed layer 52 may be a so-called self-pinned fixed layer (Synthetic Ferri Pinned layer, SFP layer). The self-pinned fixed layer has a laminated ferri structure in which a ferromagnetic layer, a non-magnetic intermediate layer, and a ferromagnetic layer are stacked, and two ferromagnetic layers are antiferromagnetically coupled. If the magnetization fixed layer 52 is a self-pinned fixed layer, the antiferromagnetic layer 51 may be omitted.

[0048] Furthermore, the arrangement of layers 51-54 in the MR element 50 may be reversed vertically from the arrangement shown in Figure 6.

[0049] Next, the direction of magnetization of the magnetization fixed layer 52 in each of the first to fourth resistive sections R11 to R14 of the first bridge circuit 11 and the sensitivity of each of the first to fourth resistive sections R11 to R14 will be described. The plurality of MR elements 50 include a plurality of first MR elements 50A1 constituting the first resistive section R11, a plurality of second MR elements 50B1 constituting the second resistive section R12, a plurality of third MR elements 50C1 constituting the third resistive section R13, and a plurality of fourth MR elements 50D1 constituting the fourth resistive section R14.

[0050] Here, the direction obtained by averaging the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple first MR elements 50A1 is called the first magnetization direction m11, the direction obtained by averaging the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple second MR elements 50B1 is called the second magnetization direction m12, the direction obtained by averaging the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple third MR elements 50C1 is called the third magnetization direction m13, and the direction obtained by averaging the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple fourth MR elements 50D1 is called the fourth magnetization direction m14.

[0051] The magnetization direction of each of the multiple magnetization fixed layers 52 included in the multiple first MR elements 50A1 may coincide with the first magnetization direction m11. Alternatively, the magnetization directions of at least some of the multiple magnetization fixed layers 52 may not coincide with the first magnetization direction m11, as long as the requirement that the average direction of the magnetization directions of the multiple magnetization fixed layers 52 is equal to the first magnetization direction m11 is satisfied.

[0052] The above description of the multiple first MR elements 50A1 also applies to the multiple second MR elements 50B1, the multiple third MR elements 50C1, and the multiple fourth MR elements 50D1.

[0053] Of the first to fourth resistive sections R11 to R14, three resistive sections are configured such that the three magnetization directions corresponding to the three resistive sections intersect each other at angles other than 0° and 180°. Of the first to fourth resistive sections R11 to R14, the remaining resistive section may be configured such that the magnetization direction corresponding to the remaining resistive section intersects each of the above three magnetization directions at angles other than 0° and 180°, or it may be configured to be in the same direction as any of the above three magnetization directions. In particular, in this embodiment, the first to fourth resistive sections R11 to R14 are configured such that the first to fourth magnetization directions m11 to m14 intersect each other at angles other than 0° and 180°.

[0054] The first resistor R11 has sensitivity in a first direction parallel to the first reference direction M11. The second resistor R12 has sensitivity in a second direction parallel to the second reference direction M12. The third resistor R13 has sensitivity in a third direction parallel to the third reference direction M13. The fourth resistor R14 has sensitivity in a fourth direction parallel to the fourth reference direction M14. In Figure 4, the first to fourth reference directions M11 to M14 are represented by arrows labeled M11 to M14, respectively.

[0055] Of the first to fourth resistors R11 to R14, three resistors are configured such that the three sensitivity directions (three reference directions) corresponding to the three resistors intersect each other at angles other than 0° and 180°. Of the first to fourth resistors R11 to R14, the remaining resistor may be configured such that the sensitivity direction corresponding to the remaining resistor intersects each of the above three sensitivity directions (three reference directions) at angles other than 0° and 180°, or it may be configured to be in the same direction as any of the above three sensitivity directions (three reference directions). In the example shown in Figure 4, the first to fourth resistors R11 to R14 are configured such that the first to fourth directions (first to fourth reference directions M11 to M14) intersect each other at angles other than 0° and 180°.

[0056] The first reference direction M11 may coincide with the first magnetization direction m11, or it may be different from the first magnetization direction m11. If the first reference direction M11 is different from the first magnetization direction m11, the first resistive section R11 may include, in addition to the plurality of first MR elements 50A1, at least one MR element 50 including a magnetization fixing layer 52 having a magnetization direction different from the first magnetization direction m11. In the following description, the first reference direction M11 is assumed to coincide with the first magnetization direction m11.

[0057] The above description of the first reference direction M11 and the first magnetization direction m11 also applies to the second reference direction M12 and the second magnetization direction m12, the third reference direction M13 and the third magnetization direction m13, and the fourth reference direction M14 and the fourth magnetization direction m14. In the following description, the second reference direction M12 coincides with the second magnetization direction m12, the third reference direction M13 coincides with the third magnetization direction m13, and the fourth reference direction M14 coincides with the fourth magnetization direction m14.

[0058] Next, the direction of magnetization of the magnetization fixed layer 52 in each of the first to fourth resistive sections R21 to R24 of the second bridge circuit 12 and the sensitivity of each of the first to fourth resistive sections R21 to R24 will be described. The plurality of MR elements 50 further includes a plurality of first MR elements 50A2 constituting the first resistive section R21, a plurality of second MR elements 50B2 constituting the second resistive section R22, a plurality of third MR elements 50C2 constituting the third resistive section R23, and a plurality of fourth MR elements 50D2 constituting the fourth resistive section R24.

[0059] Here, the direction obtained by averaging the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple first MR elements 50A2 is called the first magnetization direction m21, the direction obtained by averaging the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple second MR elements 50B2 is called the second magnetization direction m22, the direction obtained by averaging the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple third MR elements 50C2 is called the third magnetization direction m23, and the direction obtained by averaging the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple fourth MR elements 50D2 is called the fourth magnetization direction m24.

[0060] The explanation above for the first to fourth magnetization directions m11 to m14 also applies to the first to fourth magnetization directions m21 to m24. If we replace the first to fourth resistive parts R11 to R14 and the first to fourth magnetization directions m11 to m14 with the first to fourth resistive parts R21 to R24 and the first to fourth magnetization directions m21 to m24, respectively, then we get the explanation for the first to fourth magnetization directions m21 to m24.

[0061] The first resistor R21 has sensitivity in a first direction parallel to the first reference direction M21. The second resistor R22 has sensitivity in a second direction parallel to the second reference direction M22. The third resistor R23 has sensitivity in a third direction parallel to the third reference direction M23. The fourth resistor R24 ​​has sensitivity in a fourth direction parallel to the fourth reference direction M24. In Figure 4, the first to fourth reference directions M21 to M24 are represented by arrows labeled M21 to M24, respectively.

[0062] The above-mentioned explanation of the first to fourth directions of the first to fourth resistance sections R11 to R14 also applies to the first to fourth directions of the first to fourth resistance sections R21 to R24. If we replace the first to fourth resistance sections R11 to R14, the first to fourth reference directions M11 to M14, and the first to fourth magnetization directions m11 to m14 in the explanation of the first to fourth directions of the first to fourth resistance sections R11 to R14 with the first to fourth resistance sections R21 to R24, the first to fourth reference directions M21 to M24, and the first to fourth magnetization directions m21 to m24, respectively, then we get the explanation of the first to fourth directions of the first to fourth resistance sections R21 to R24.

[0063] Next, with reference to Figures 4 and 5, examples of the first to fourth magnetization directions m11 to m14, the first to fourth magnetization directions m21 to m24, the first to fourth reference directions M11 to M14, and the first to fourth reference directions M21 to M24 will be described. Figure 5 shows the direction of the first magnetization direction m11. The first magnetization direction m11 is the direction rotated 151° counterclockwise from the reference direction DR. That is, the angle between the reference direction DR and the first magnetization direction m11 is 151°. Note that this angle, like the rotating magnetic field angle θ, is expressed as a positive value when viewed counterclockwise from the reference direction DR and as a negative value when viewed clockwise from the reference direction DR. In the following explanation, the first magnetization direction m11 will be expressed as the angle between the reference direction DR and the first magnetization direction m11. Magnetization directions other than the first magnetization direction m11, as well as the reference direction, are expressed in the same manner as the first magnetization direction m11.

[0064] As mentioned above, the first reference direction M11 coincides with the first magnetization direction m11. As shown in Figure 4, the first reference direction M11 is 151°. Also as shown in Figure 4, the second reference direction M12 is 290°, the third reference direction M13 is 154°, and the fourth reference direction M14 is 184°. Although not shown, the second magnetization direction m12 is 290°, the third magnetization direction m13 is 154°, and the fourth magnetization direction m14 is 184°.

[0065] Furthermore, as shown in Figure 4, the first reference direction M21 is 97°, the second reference direction M22 is 252°, the third reference direction M23 is 100°, and the fourth reference direction M24 is 280°. Although not shown, the first magnetization direction m21 is 97°, the second magnetization direction m22 is 252°, the third magnetization direction m23 is 100°, and the fourth magnetization direction m24 is 280°.

[0066] Furthermore, the magnetization direction and reference direction may be slightly deviated from the above-mentioned directions from the viewpoint of the accuracy of the fabrication of the MR element 50.

[0067] Next, the configuration of the logic signal generation circuit 20 will be described with reference to Figure 4. The logic signal generation circuit 20 is configured to acquire a first detection signal S1 and a second detection signal S2, generate and output a first logic signal Su using the first detection signal S1, generate and output a second logic signal Sv having a different phase from the first logic signal Su using the second detection signal S2, and generate and output a third logic signal Sw having a different phase from the first logic signal Su and the second logic signal Sv using the first detection signal S1 and the second detection signal S2.

[0068] The logic signal generation circuit 20 can be implemented, for example, by an application-specific integrated circuit (ASIC) or multiple comparators. A logic signal generation circuit 20 that can be configured to have a chip form factor, such as the logic signal generation circuit 20 implemented by an ASIC, is also specifically called a "logic signal generator."

[0069] The logic signal generation circuit 20 includes a power terminal 20a, a ground terminal 20b, a first input terminal 20c, a second input terminal 20d, a first output terminal 20e, a second output terminal 20f, a third output terminal 20g, a first comparator 21, a second comparator 22, a third comparator 23, and two resistors 24 and 25. The first comparator 21 has a first input terminal 21a, a second input terminal 21b, and an output terminal 21c. The second comparator 22 has a first input terminal 22a, a second input terminal 22b, and an output terminal 22c. The third comparator 23 has a first input terminal 23a, a second input terminal 23b, and an output terminal 23c.

[0070] One end of resistor 24 is connected to power terminal 20a. One end of resistor 25 is connected to the other end of resistor 24. The other end of resistor 25 is connected to ground terminal 20b. A voltage of a predetermined magnitude is applied to power terminal 20a. Ground terminal 20b is connected to ground.

[0071] The first input terminal 21a of the first comparator 21 and the first input terminal 23a of the third comparator 23 are connected to the first input terminal 20c. The first input terminal 22a of the second comparator 22 and the second input terminal 23b of the third comparator 23 are connected to the second input terminal 20d. The second input terminal 21b of the first comparator 21 and the second input terminal 22b of the second comparator 22 are connected to the connection point of resistors 24 and 25.

[0072] The first output terminal 10c of the detection circuit 10 is connected to the first input terminal 20c of the logic signal generation circuit 20. The first output terminal 10c is connected to the first input terminal 21a of the first comparator 21 and the first input terminal 23a of the third comparator 23 via the first input terminal 20c. The second output terminal 10d of the detection circuit 10 is connected to the second input terminal 20d of the logic signal generation circuit 20. The second output terminal 10d is connected to the first input terminal 22a of the second comparator 22 and the second input terminal 23b of the third comparator 23 via the second input terminal 20d.

[0073] The output terminal 21c of the first comparator 21 is connected to the first output terminal 20e. The first output terminal 20e outputs the signal output from the output terminal 21c of the first comparator 21 as the first logic signal Su.

[0074] The output terminal 22c of the second comparator 22 is connected to the second output terminal 20f. The second output terminal 20f outputs the signal output from the output terminal 22c of the second comparator 22 as the second logic signal Sv.

[0075] The output terminal 23c of the third comparator 23 is connected to the third output terminal 20g. The third output terminal 20g outputs the signal output from the output terminal 23c of the third comparator 23 as the third logic signal Sw.

[0076] Next, the first and second detection signals S1 and S2, and the first to third logic signals Su, Sv, and Sw will be described. First, the first and second detection signals S1 and S2 will be described. The first differential amplifier 13 generates a signal corresponding to the potential difference between the first and second output ports E11 and E12 as the first detection signal S1. The second differential amplifier 14 generates a signal corresponding to the potential difference between the first and second output ports E21 and E22 as the second detection signal S2.

[0077] Figure 7 is a waveform diagram showing the waveforms of the first and second detection signals S1 and S2, respectively. In Figure 7, the horizontal axis represents the rotation angle θM of the motor 70, and the vertical axis represents the magnitudes of the first and second detection signals S1 and S2, respectively. Also in Figure 7, reference numeral 91 represents the first detection signal S1, and reference numeral 92 represents the second detection signal S2. Furthermore, Figure 7 shows the range in which the rotation angle θM is between 0° and 600°. In this embodiment, the value of the rotation angle θM is equal to or approximately equal to the value of the rotating magnetic field angle θ.

[0078] Next, the first to third logic signals Su, Sv, and Sw will be described with reference to Figures 7 and 8. Figure 8 is a timing chart showing the first to third logic signals Su, Sv, and Sw.

[0079] First, the first logic signal Su will be described. The first detection signal S1 is input to the first input terminal 21a of the first comparator 21. A reference voltage with a magnitude corresponding to the value of 0 on the vertical axis in Figure 7 is input to the second input terminal 21b of the first comparator 21. The first comparator 21 compares the value of the first detection signal S1 with the value of the reference voltage and outputs the first logic signal Su. In the range of rotation angle θM shown in Figure 7, the value of the first detection signal S1 is greater than the value of the reference voltage (0 on the vertical axis in Figure 7) when the rotation angle θM satisfies the first case of 149.6° < θM < 327.8° or 509.6° < θM ≤ 600°, and is smaller than the value of the reference voltage when the rotation angle θM satisfies the second case of 0° ≤ θM < 149.6° or 327.8° < θM < 509.6°. Therefore, within the range described above, the first comparator 21 outputs a high-level signal when the rotation angle θM is first, and outputs a low-level signal when the rotation angle θM is second.

[0080] Next, the second logic signal Sv will be described. The second detection signal S2 is input to the first input terminal 22a of the second comparator 22. A reference voltage with a magnitude corresponding to the value of 0 on the vertical axis in Figure 7 is input to the second input terminal 22b of the second comparator 22. The second comparator 22 compares the value of the second detection signal S2 with the value of the reference voltage and outputs the second logic signal Sv. In the range of rotation angles θM shown in Figure 7, the value of the second detection signal S2 is greater than the value of the reference voltage in the third case where the rotation angle θM satisfies 91° < θM < 269.1° or 451° < θM ≤ 600°, and is less than the value of the reference voltage in the fourth case where the rotation angle θM satisfies 0° ≤ θM < 91° or 269.1° < θM < 451°. Therefore, within the range described above, the second comparator 22 outputs a high-level signal when the rotation angle θM is the third, and outputs a low-level signal when the rotation angle θM is the fourth.

[0081] Next, the third logic signal Sw will be described. The first detection signal S1 is input to the first input terminal 23a of the third comparator 23. The second detection signal S2 is input to the second input terminal 23b of the third comparator 23. The third comparator 23 compares the value of the first detection signal S1 with the value of the second detection signal S2 and outputs the third logic signal Sw. In the range of rotation angles θM shown in Figure 7, the value of the first detection signal S1 is greater than the value of the second detection signal S2 in the fifth case where the rotation angle θM satisfies 0°≦θM<29.5°, 207°<θM<389.5°, or 567°<θM≦600°, and is less than the value of the second detection signal S2 in the sixth case where the rotation angle θM satisfies 29.5°<θM<207° or 389.5°<θM<567°. Therefore, within the range described above, the third comparator 23 outputs a high-level signal when the rotation angle θM is the fifth, and outputs a low-level signal when the rotation angle θM is the sixth.

[0082] In this embodiment, the control circuit 121 detects the rotation angle θM using the first to third logic signals Su, Sv, and Sw. In particular, in this embodiment, the first and second bridge circuits 11 and 12 are configured such that a time interval corresponding to one rotation in the direction of the rotation angle θM is divided into three or more time sub-intervals based on the first detection signal S1 and the second detection signal S2. The control circuit 121 can detect three or more time sub-intervals using the first to third logic signals Su, Sv, and Sw. As a result, the control circuit 121 can detect the rotation angle θM. For example, if a time interval corresponding to one rotation in the direction of the rotation angle θM is divided into three sub-intervals, the control circuit 121 can detect that the direction of the rotation angle θM has rotated by approximately 1 / 3, that is, that the rotation angle θM has changed by approximately 120°. Furthermore, if the time interval corresponding to one rotation in the direction of the rotation angle θM is divided into six sub-intervals, the control circuit 121 can detect that the direction of the rotation angle θM has rotated by approximately 1 / 6, that is, that the rotation angle θM has changed by approximately 60°.

[0083] The control circuit 121 can detect three or more temporal sub-intervals by detecting, for example, the timing at which each of the first to third logic signals Su, Sv, and Sw switches from a high-level signal to a low-level signal. In Figure 8, symbol P1 indicates the timing at which the third logic signal Sw switches from a high-level signal to a low-level signal. Symbol P2 indicates the timing at which the first logic signal Su switches from a low-level signal to a high-level signal. Symbol P3 indicates the timing at which the second logic signal Sv switches from a high-level signal to a low-level signal. Symbol P4 indicates the timing at which the third logic signal Sw switches from a high-level signal to a low-level signal. Symbol P5 indicates the timing at which the first logic signal Su switches from a low-level signal to a high-level signal.

[0084] Figure 7 shows five points corresponding to timings P1 to P5 shown in Figure 8. The point corresponding to timing P1 is the point where the magnitude of the first detection signal S1 and the magnitude of the second detection signal S2 are equal, and the rotation angle θM is 29.5°. The point corresponding to timing P2 is the point where the magnitude of the first detection signal S1 is 0, and the rotation angle θM is 149.6°. The point corresponding to timing P3 is the point where the magnitude of the second detection signal S2 is 0, and the rotation angle θM is 269.1°. The point corresponding to timing P4 is the point where the magnitude of the first detection signal S1 and the magnitude of the second detection signal S2 are equal, and the rotation angle θM is 389.5°. The point corresponding to timing P5 is the point where the magnitude of the first detection signal S1 is 0, and the rotation angle θM is 509.6°.

[0085] In the temporal sub-interval from timing P1 to timing P2, the rotation angle θM changes by 120.1°. In the temporal sub-interval from timing P2 to timing P3, the rotation angle θM changes by 119.5°. In the temporal sub-interval from timing P3 to timing P4, the rotation angle θM changes by 120.4°. In the temporal sub-interval from timing P4 to timing P5, the rotation angle θM changes by 120.1°. Therefore, the control circuit 121 can effectively detect the temporal sub-interval by detecting timings P1 to P5. As a result, the control circuit 121 can detect that the rotation angle θM has changed by approximately 120°.

[0086] The timing for detecting the rotation angle θM (hereinafter referred to as the detection timing) can be as follows: For example, if the first detection timing is when the first logic signal Su switches from a high-level signal to a low-level signal, then the second detection timing is when the second logic signal Sv switches from a high-level signal to a low-level signal, then the third detection timing is when the third logic signal Sw switches from a high-level signal to a low-level signal, and then the fourth detection timing is when the first logic signal Su switches from a high-level signal to a low-level signal.

[0087] Alternatively, if the detection timing is determined by detecting multiple instances where one of the first to third logic signals Su, Sv, or Sw switches from a high-level signal to a low-level signal, the third detection timing counting from the first detection timing can be designated as the second detection timing, the fifth detection timing counting from the first detection timing can be designated as the third detection timing, and the seventh detection timing counting from the first detection timing can be designated as the fourth detection timing.

[0088] Next, a method for manufacturing the magnetic sensor 1 according to this embodiment will be described. The method for manufacturing the magnetic sensor 1 includes the steps of forming a first bridge circuit 11 and forming a second bridge circuit 12. The step of forming the first bridge circuit 11 includes an element formation step of forming a plurality of MR elements 50 and a step of forming a plurality of wires so that first to fourth resistance sections R11 to R14 are formed. The step of forming the second bridge circuit 12 includes an element formation step of forming a plurality of MR elements 50 and a step of forming a plurality of wires so that first to fourth resistance sections R21 to R24 are formed.

[0089] The element formation process will be described below using the first bridge circuit 11 as an example. Figure 9 is a flowchart of the element formation process for the first bridge circuit 11. In the element formation process, first, a laminated film is formed which includes a plurality of first magnetic parts that will later become a plurality of magnetization fixed layers 52 and a plurality of second magnetic parts that will later become a plurality of free layers 54 (step S10). The laminated film further includes a non-magnetic layer that will later become a plurality of gap layers 53 and an antiferromagnetic layer that will later become a plurality of antiferromagnetic layers 51. Next, a fixing process is performed which fixes the magnetization direction of each of the plurality of first magnetic parts using laser light and an external magnetic field in a predetermined direction (step S20). The fixing process includes a first step (step S21), a second step (step S22), a third step (step S23), and a fourth step (step S24).

[0090] In the first step (step S21), the magnetization direction of a specific first magnetic part, which will later become the magnetization fixing layers 52 of the multiple first MR elements 50A1 that constitute the first resistive part R11, is fixed. Specifically, a laser beam is irradiated onto the portion of the laminated film containing the specific first magnetic part while applying an external magnetic field in the same direction as the first magnetization direction m11 shown in Figure 5 (the same as the first reference direction M11 shown in Figure 4). If the laminated film contains an antiferromagnetic layer, the laser beam is irradiated such that the temperature of the laminated film irradiated with the laser beam is above the blocking temperature of the antiferromagnetic layer. The temperature of the laminated film can be adjusted, for example, by the intensity or pulse width of the laser beam. After irradiation with the laser beam, when the temperature of the laminated film falls below the blocking temperature, the magnetization direction of the specific first magnetic part is fixed to the first magnetization direction m11.

[0091] In the second step (step S22), similar to the first step, the magnetization direction of a specific second magnetic portion, which will later become the magnetization fixing layer 52 of the multiple second MR elements 50B1 that constitute the second resistance portion R12 among the multiple first magnetic portions, is fixed. Specifically, while applying an external magnetic field in the same direction as the second magnetization direction m12 (the same as the second reference direction M12 shown in Figure 4), laser light is irradiated onto the portion of the laminated film that includes the specific second magnetic portion. Through the second step, the magnetization direction of the specific second magnetic portion is fixed to the second magnetization direction m12.

[0092] In the third step (step S23), similar to the first step, the magnetization direction of a third specific magnetic part, which will later become the magnetization fixing layer 52 of the multiple third MR elements 50C1 that constitute the third resistance part R13, is fixed. Specifically, while applying an external magnetic field in the same direction as the third magnetization direction m13 (the same as the third reference direction M13 shown in Figure 4), laser light is irradiated onto the portion of the laminated film containing the third specific magnetic part. Through the third step, the magnetization direction of the third specific magnetic part is fixed to the third magnetization direction m13.

[0093] In the fourth step (step S24), similar to the first step, the magnetization direction of a specific fourth magnetic portion, which will later become the magnetization fixing layers 52 of the multiple fourth MR elements 50D1 that constitute the fourth resistive portion R14 among the multiple first magnetic portions, is fixed. Specifically, while applying an external magnetic field in the same direction as the fourth magnetization direction m14 (the same as the fourth reference direction M14 shown in Figure 4), laser light is irradiated onto the portion of the laminated film that includes the specific fourth magnetic portion. Through the fourth step, the magnetization direction of the specific fourth magnetic portion is fixed to the fourth magnetization direction m14.

[0094] Note that the order of steps 1 through 4 is not limited to the example shown in Figure 9 and is arbitrary. Also, the direction of the external magnetic field may be set by changing the direction of the external magnetic field itself, or by changing the orientation of the laminated film.

[0095] The element formation process further includes a process of patterning the multilayer film so that it forms multiple MR elements 50. This process may be performed after the fixing process, or between the process of forming the multilayer film and the fixing process.

[0096] Up to this point, we have explained the element formation process using the process of forming the first bridge circuit 11 as an example. The element formation process for forming the second bridge circuit 12 is basically the same as the element formation process for forming the first bridge circuit 11. If the first to fourth resistive sections R11 to R14, the first to fourth MR elements 50A1, 50B1, 50C1, 50D1, the first to fourth magnetization directions m11 to m14, and the first to fourth reference directions M11 to M14 in the description of the element formation process for forming the first bridge circuit 11 are replaced with the first to fourth resistive sections R21 to R24, the first to fourth MR elements 50A2, 50B2, 50C2, 50D2, the first to fourth magnetization directions m21 to m24, and the first to fourth reference directions M21 to M24, respectively, then the description becomes the element formation process for forming the second bridge circuit 12.

[0097] Next, a design method for the magnetic sensor 1 according to this embodiment will be described. The design method for the magnetic sensor 1 is a method for setting the magnetization direction of the magnetization fixed layer 52 so that the magnetic sensor 1 can be used for rotation control of the motor 70. Figure 10 is a flowchart of the design method for the magnetic sensor 1. The design method for the magnetic sensor 1 includes a first setting step (step S101) and a second setting step (step S102).

[0098] In the first setting step (S101), the magnetization directions of the multiple magnetization fixed layers 52 of the multiple first MR elements 50A1 constituting the first resistor R11, the magnetization directions of the multiple second MR elements 50B1 constituting the second resistor R12, the magnetization directions of the multiple third MR elements 50C1 constituting the third resistor R13, and the magnetization directions of the multiple fourth MR elements 50D1 constituting the fourth resistor R14 are set so that the first bridge circuit 11 generates the first detection signal S1. In this embodiment, the first setting step is performed such that the average direction of the magnetization directions of the multiple magnetization fixed layers 52 of the first MR element 50A1 becomes the first magnetization direction m11, the average direction of the magnetization directions of the multiple magnetization fixed layers 52 of the second MR element 50B1 becomes the second magnetization direction m12, the average direction of the magnetization directions of the multiple magnetization fixed layers 52 of the third MR element 50C1 becomes the third magnetization direction m13, and the average direction of the magnetization directions of the multiple magnetization fixed layers 52 of the fourth MR element 50D1 becomes the fourth magnetization direction m14.

[0099] Furthermore, in the first setting step, the magnetization directions of the multiple magnetization fixed layers 52 of the multiple first MR elements 50A2 constituting the first resistor R21, the magnetization directions of the multiple magnetization fixed layers 52 of the multiple second MR elements 50B2 constituting the second resistor R22, the magnetization directions of the multiple magnetization fixed layers 52 of the multiple third MR elements 50C2 constituting the third resistor R23, and the magnetization directions of the multiple magnetization fixed layers 52 of the multiple fourth MR elements 50D2 constituting the fourth resistor R24 ​​are set so that the second bridge circuit 12 generates the second detection signal S2. In this embodiment, the first setting step is performed such that the average direction of the magnetization of the multiple magnetization fixed layers 52 of the first MR element 50A2 becomes the first magnetization direction m21, the average direction of the magnetization of the multiple magnetization fixed layers 52 of the second MR element 50B2 becomes the second magnetization direction m22, the average direction of the magnetization of the multiple magnetization fixed layers 52 of the third MR element 50C2 becomes the third magnetization direction m23, and the average direction of the magnetization of the multiple magnetization fixed layers 52 of the fourth MR element 50D2 becomes the fourth magnetization direction m24.

[0100] In the second setting step (step S102), the magnetization directions of the aforementioned multiple magnetization fixed layers 52 are set such that a time interval corresponding to one rotation (rotation by rotation angle θM) in the direction of the rotating magnetic field MF is divided into three or more time sub-intervals based on the first detection signal S1 and the second detection signal S2. In this embodiment in particular, in the second setting step, the magnetization directions m11~m14 and m21~m24 are set.

[0101] When the direction of the rotating magnetic field MF rotates with a predetermined period, each of the first and second detection signals S1 and S2 includes an ideal component that changes periodically to trace an ideal sinusoidal curve, and multiple harmonic components corresponding to higher-order harmonics of the ideal component. When the first to fourth magnetization directions m11 to m14 are changed, the initial phase of the multiple harmonic components changes, thereby changing the waveform of the first detection signal S1. Similarly, when the first to fourth magnetization directions m21 to m24 are changed, the initial phase of the multiple harmonic components changes, thereby changing the waveform of the second detection signal S2. In the second setting step, the magnetization directions of the multiple magnetization fixed layers 52 are set so that three or more temporal sub-intervals are obtained by utilizing the influence of the first to fourth magnetization directions m11 to m14 on the waveform of the first detection signal S1 and the influence of the first to fourth magnetization directions m21 to m24 on the waveform of the second detection signal S2.

[0102] In this embodiment, the magnetization direction of the multiple magnetization fixed layers 52 is set such that the above sub-section corresponds to a change of within 120° ± α in the direction of the rotating magnetic field MF. In this way, first and second bridge circuits 11 and 12 are configured to generate first and second detection signals S1 and S2 that can be used to control the rotation of the motor 70 using the magnetic sensor 1. α is preferably, for example, 10°.

[0103] Next, the operation and effects of the magnetic sensor 1 according to this embodiment will be described. In this embodiment, of the first to fourth resistive sections R11 to R14 of the first bridge circuit 11, three resistive sections are configured such that the three magnetization directions corresponding to the three resistive sections intersect each other at angles other than 0° and 180°. In particular in this embodiment, the first to fourth resistive sections R11 to R14 are configured such that the first to fourth magnetization directions m11 to m14 intersect each other at angles other than 0° and 180°. Also in this embodiment, of the first to fourth resistive sections R21 to R24 of the second bridge circuit 12, three resistive sections are configured such that the three magnetization directions corresponding to the three resistive sections intersect each other at angles other than 0° and 180°. In particular in this embodiment, the first to fourth resistive sections R21 to R24 are configured such that the first to fourth magnetization directions m21 to m24 intersect each other at angles other than 0° and 180°. As a result, according to this embodiment, three or more temporal sub-intervals can be detected based on the first detection signal S1 generated by the first bridge circuit 11 and the second detection signal S2 generated by the second bridge circuit 12, and the rotation angle θM can also be detected. Consequently, according to this embodiment, the first and second detection signals S1 and S2 can be used for rotation control of the motor 70.

[0104] The above effects will be explained in detail below, with reference to the comparative example magnetic sensor. First, the configuration of the comparative example magnetic sensor 101 will be described with reference to Figure 11. Figure 11 is a circuit diagram showing the circuit configuration of the comparative example magnetic sensor 101. The comparative example magnetic sensor 101 includes a first bridge circuit 111 and a second bridge circuit 112 instead of the first and second bridge circuits 11 and 12 in this embodiment. The other configurations of the comparative example magnetic sensor 101 are the same as those of the magnetic sensor 1 in this embodiment.

[0105] The configuration of the first bridge circuit 111 is basically the same as the configuration of the first bridge circuit 11 in this embodiment. However, in the first bridge circuit 111, the direction of sensitivity of each of the first to fourth resistors R11 to R14 is different from the direction of sensitivity of each of the first to fourth resistors R11 to R14 in this embodiment. That is, in the comparative example, the first resistor R11 has sensitivity in a first direction parallel to the first reference direction M111, the second resistor R12 has sensitivity in a second direction parallel to the second reference direction M112, the third resistor R13 has sensitivity in a third direction parallel to the third reference direction M113, and the fourth resistor R14 has sensitivity in a fourth direction parallel to the fourth reference direction M114. As shown in Figure 11, the first reference direction M111 and the third reference direction M113 are 90° apart, and the second reference direction M112 and the fourth reference direction M114 are 270° apart.

[0106] In the comparative example, the first magnetization direction, which is the average direction of the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple first MR elements 50A1 constituting the first resistance section R11, is the same direction as the first reference direction M111. The second magnetization direction, which is the average direction of the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple second MR elements 50B1 constituting the second resistance section R12, is the same direction as the second reference direction M112. The third magnetization direction, which is the average direction of the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple third MR elements 50C1 constituting the third resistance section R13, is the same direction as the third reference direction M113. The fourth magnetization direction, which is the average direction of the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple fourth MR elements 50D1 constituting the fourth resistance section R14, is the same direction as the fourth reference direction M114.

[0107] The first magnetization direction and the third magnetization direction are in the same direction, the second magnetization direction and the fourth magnetization direction are in the same direction, the first magnetization direction and the second magnetization direction are 180° apart, and the third magnetization direction and the fourth magnetization direction are 180° apart. Therefore, in the comparative example, the first to fourth resistors R11 to R14 are not configured such that the first to fourth magnetization directions intersect each other.

[0108] The configuration of the second bridge circuit 112 is basically the same as the configuration of the second bridge circuit 12 in this embodiment. However, in the second bridge circuit 112, the direction of sensitivity of each of the first to fourth resistors R21 to R24 is different from the direction of sensitivity of each of the first to fourth resistors R21 to R24 in this embodiment. That is, in the comparative example, the first resistor R21 has sensitivity in a first direction parallel to the first reference direction M121, the second resistor R22 has sensitivity in a second direction parallel to the second reference direction M122, the third resistor R23 has sensitivity in a third direction parallel to the third reference direction M123, and the fourth resistor R24 ​​has sensitivity in a fourth direction parallel to the fourth reference direction M124. As shown in Figure 11, the first reference direction M121 and the third reference direction M123 are 0°, and the second reference direction M122 and the fourth reference direction M124 are 180°.

[0109] In the comparative example, the first magnetization direction, which is the average direction of the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple first MR elements 50A2 constituting the first resistance section R21, is the same direction as the first reference direction M121. The second magnetization direction, which is the average direction of the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple second MR elements 50B2 constituting the second resistance section R22, is the same direction as the second reference direction M122. The third magnetization direction, which is the average direction of the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple third MR elements 50C2 constituting the third resistance section R23, is the same direction as the third reference direction M113. The fourth magnetization direction, which is the average direction of the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple fourth MR elements 50D2 constituting the fourth resistance section R14, is the same direction as the fourth reference direction M114.

[0110] The first magnetization direction and the third magnetization direction are in the same direction, the second magnetization direction and the fourth magnetization direction are in the same direction, the first magnetization direction and the second magnetization direction are 180° apart, and the third magnetization direction and the fourth magnetization direction are 180° apart. Therefore, in the comparative example, the first to fourth resistors R21 to R24 are not configured such that the first to fourth magnetization directions intersect each other.

[0111] Next, the first and second detection signals S1 and S2 of the comparative example will be described with reference to Figure 12. Figure 12 is a waveform diagram showing the waveforms of the first and second detection signals S1 and S2 of the comparative example. In Figure 12, the horizontal axis represents the rotation angle θM of the motor 70, and the vertical axis represents the magnitude of the first and second detection signals S1 and S2 of the comparative example. Also in Figure 12, reference numeral 191 represents the first detection signal S1 of the comparative example, and reference numeral 192 represents the second detection signal S2 of the comparative example. Furthermore, Figure 12 shows the range in which the rotation angle θM is between 0° and 600°.

[0112] In the range of rotation angles θM shown in Figure 12, the value of the first detection signal S1 of the comparative example is greater than the value of the reference voltage (0 on the vertical axis in Figure 12) when the rotation angle θM satisfies 83° < θM < 262.7° or 443° < θM ≤ 600°, and is smaller than the value of the reference voltage when the rotation angle θM satisfies 0° ≤ θM < 83° or 262.7° < θM < 443°.

[0113] Furthermore, within the range of rotation angle θM shown in Figure 12, the value of the second detection signal S2 in the comparative example is greater than the reference voltage value when the rotation angle θM satisfies 0° ≤ θM < 178.8° or 358.8° < θM < 538.8°, and less than the reference voltage value when the rotation angle θM satisfies 178.8° < θM < 358.8° or 538.8° < θM ≤ 600°.

[0114] Furthermore, within the range of rotation angles θM shown in Figure 12, the value of the first detection signal S1 in the comparative example is greater than the second detection signal S2 when the rotation angle θM satisfies 158.7° < θM < 338.6° or 518.7° < θM ≤ 600°, and is smaller than the value of the second detection signal S2 when the rotation angle θM satisfies 0° ≤ θM < 158.7° or 338.6° < θM < 518.7°.

[0115] The comparative example logic signal generation circuit 20 generates first to third logic signals Su, Sv, and Sw using the first and second detection signals S1 and S2 of the comparative example, similar to this embodiment. However, in the comparative example, the first to third logic signals Su, Sv, and Sw cannot be used for rotation control of the motor 70. For example, if the timing of switching between a high-level signal and a low-level signal for any of the first to third logic signals Su, Sv, and Sw is detected multiple times, the third timing counting from the first detection timing is designated as the second detection timing, the fifth timing counting from the first detection timing is designated as the third detection timing, and the seventh timing counting from the first detection timing is designated as the fourth detection timing. If the first detection timing is defined as the timing when the rotation angle θM is 0°, then the second detection timing is when the rotation angle θM is 158.7°, the third detection timing is when the rotation angle θM is 262.7°, and the fourth detection timing is when the rotation angle θM is 358.8°.

[0116] In the temporal sub-interval from the first detection timing to the second detection timing, the rotation angle θM changes by 158.7°. In the temporal sub-interval from the second detection timing to the third detection timing, the rotation angle θM changes by 104°. In the temporal sub-interval from the third detection timing to the fourth detection timing, the rotation angle θM changes by 96.1°. In order to use the first to third logic signals Su, Sv, and Sw for rotation control of the motor 70, it is necessary that the amount of change in the rotation angle θM is the same or approximately the same across the multiple temporal sub-intervals detected by the control circuit 121. However, in the comparative example, the amount of change in the rotation angle θM differs for each temporal sub-interval.

[0117] In contrast, in this embodiment, as described above, the amount of change in the rotation angle θM is approximately 120° in any of the multiple temporal sub-intervals detected by the control circuit 121. As a result, according to this embodiment, the first to third logic signals Su, Sv, Sw, i.e., the first and second detection signals S1, S2 can be used for rotation control of the motor 70.

[0118] [Differentiation] Next, first to third modifications of the magnetic sensor 1 according to this embodiment will be described. First, the first modification of the magnetic sensor 1 will be described. In the first modification, the configuration of the third resistor R13 of the first bridge circuit 11 is different from the example shown in Figure 4. As mentioned above, the third resistor R13 has sensitivity in a third direction parallel to the third reference direction M13. In the first modification, the third reference direction M13 is 151°, which is the same direction as the first reference direction M11. Although not shown, the third magnetization direction m13, which is the average direction of the magnetization directions of the multiple magnetization fixed layers 52 included in the multiple third MR elements 50C1 constituting the third resistor R13, is also 151°. Therefore, the third magnetization direction m13 is in the same direction as the first magnetization direction m11, which is the average direction of the magnetization directions of the multiple magnetization fixed layers 52 included in the multiple first MR elements 50A1 that constitute the first resistive section R11.

[0119] Figure 13 is a waveform diagram showing the waveforms of the first and second detection signals S1 and S2 in the first modified example. In Figure 13, the horizontal axis represents the rotation angle θM of the motor 70, and the vertical axis represents the magnitudes of the first and second detection signals S1 and S2. Also in Figure 13, reference numeral 291 represents the first detection signal S1, and reference numeral 292 represents the second detection signal S2. Furthermore, Figure 13 shows the range in which the rotation angle θM is between 0° and 600°.

[0120] In the range of rotation angle θM shown in Figure 13, the value of the first detection signal S1 is greater than the value of the reference voltage (0 on the vertical axis in Figure 13) when the rotation angle θM satisfies the first case, which is 148.8° < θM < 326.9° or 508.8° < θM ≤ 600°, and less than the value of the reference voltage when the rotation angle θM satisfies the second case, which is 0° ≤ θM < 148.8° or 326.9° < θM < 508.8°. Therefore, in the above range, the first comparator 21 (see Figure 4) outputs a high-level signal when the rotation angle θM is the first case, and outputs a low-level signal when the rotation angle θM is the second case.

[0121] In the range of rotation angle θM shown in Figure 13, the value of the second detection signal S2 is greater than the value of the reference voltage when the rotation angle θM satisfies the third case, which is 91° < θM < 269.1° or 451° < θM ≤ 600°, and is less than the value of the reference voltage when the rotation angle θM satisfies the fourth case, which is 0° ≤ θM < 91° or 269.1° < θM < 451°. Therefore, in the above range, the second comparator 22 (see Figure 4) outputs a high-level signal when the rotation angle θM is the third case and outputs a low-level signal when the rotation angle θM is the fourth case.

[0122] In the range of rotation angles θM shown in Figure 13, the value of the first detection signal S1 is greater than the value of the second detection signal S2 when the rotation angle θM satisfies the fifth case: 0° ≤ θM < 29.6°, 207° < θM < 389.6°, or 567° < θM ≤ 600°. When the rotation angle θM satisfies the sixth case: 29.6° < θM < 207° or 389.6° < θM < 567°, the value of the first detection signal S1 is greater than the value of the second detection signal S2. Therefore, in the above range, the third comparator 23 (see Figure 4) outputs a high-level signal when the rotation angle θM is the fifth case and outputs a low-level signal when the rotation angle θM is the sixth case.

[0123] Point P1 shown in Figure 13 is the point where the magnitude of the first detection signal S1 and the magnitude of the second detection signal S2 are equal, and the rotation angle θM is 29.6°. Point P2 is the point where the magnitude of the first detection signal S1 is 0, and the rotation angle θM is 148.8°. Point P3 is the point where the magnitude of the second detection signal S2 is 0, and the rotation angle θM is 269.1°. Point P4 is the point where the magnitude of the first detection signal S1 and the magnitude of the second detection signal S2 are equal, and the rotation angle θM is 389.6°. Point P5 is the point where the magnitude of the first detection signal S1 is 0, and the rotation angle θM is 508.8°.

[0124] In the time sub-interval from the timing corresponding to point P1 to the timing corresponding to point P2, the rotation angle θM changes by 119.2°. In the time sub-interval from the timing corresponding to point P2 to the timing corresponding to point P3, the rotation angle θM changes by 120.3°. In the time sub-interval from the timing corresponding to point P3 to the timing corresponding to point P4, the rotation angle θM changes by 120.5°. In the time sub-interval from the timing corresponding to point P4 to the timing corresponding to point P5, the rotation angle θM changes by 119.2°.

[0125] Next, a second modified example of the magnetic sensor 1 will be described. In the second modified example, the configuration of the first resistor R21 of the second bridge circuit 12 is different from the example shown in Figure 4. As mentioned above, the first resistor R21 has sensitivity in a first direction parallel to the first reference direction M21. In the second modified example, the first reference direction M21 is 100°, which is the same direction as the third reference direction M23. Although not shown, the first magnetization direction m21, which is the average direction of the magnetization directions of the multiple magnetization fixed layers 52 included in the multiple first MR elements 50A2 that constitute the first resistor R21, is also 100°. Therefore, the first magnetization direction m21 is the same direction as the third magnetization direction m23, which is the average direction of the magnetization directions of the multiple magnetization fixed layers 52 included in the multiple third MR elements 50C2 that constitute the third resistor R23.

[0126] Figure 14 is a waveform diagram showing the waveforms of the first and second detection signals S1 and S2 in the second modified example. In Figure 14, the horizontal axis represents the rotation angle θM of the motor 70, and the vertical axis represents the magnitudes of the first and second detection signals S1 and S2. Also in Figure 14, reference numeral 391 represents the first detection signal S1, and reference numeral 392 represents the second detection signal S2. Furthermore, Figure 14 shows the range in which the rotation angle θM is between 0° and 600°.

[0127] In the range of rotation angle θM shown in Figure 14, the value of the first detection signal S1 is greater than the value of the reference voltage (0 on the vertical axis of Figure 14) when the rotation angle θM satisfies the first case, which is 149.6° < θM < 327.8° or 509.6° < θM ≤ 600°, and less than the value of the reference voltage when the rotation angle θM satisfies the second case, which is 0° ≤ θM < 149.6° or 327.8° < θM < 509.6°. Therefore, in the above range, the first comparator 21 (see Figure 4) outputs a high-level signal when the rotation angle θM is the first case, and outputs a low-level signal when the rotation angle θM is the second case.

[0128] In the range of rotation angle θM shown in Figure 14, the value of the second detection signal S2 is greater than the value of the reference voltage in the third case where the rotation angle θM satisfies 93.3° < θM < 271.3° or 453.3° < θM ≤ 600°, and is less than the value of the reference voltage in the fourth case where the rotation angle θM satisfies 0° ≤ θM < 93.3° or 271.3° < θM < 453.3°. Therefore, in the above range, the second comparator 22 (see Figure 4) outputs a high-level signal when the rotation angle θM is in the third case and a low-level signal when the rotation angle θM is in the fourth case.

[0129] In the range of rotation angles θM shown in Figure 14, the value of the first detection signal S1 is greater than the value of the second detection signal S2 when the rotation angle θM satisfies the fifth case, 0° ≤ θM < 30.3°, 207.9° < θM < 390.3°, or 567.9° < θM ≤ 600°, and is less than the value of the second detection signal S2 when the rotation angle θM satisfies the sixth case, 30.3° < θM < 207.9° or 390.3° < θM < 567.9°. Therefore, in the above range, the third comparator 23 (see Figure 4) outputs a high-level signal when the rotation angle θM is the fifth case and outputs a low-level signal when the rotation angle θM is the sixth case.

[0130] Point P1 shown in Figure 14 is the point where the magnitude of the first detection signal S1 and the magnitude of the second detection signal S2 are equal, and the rotation angle θM is 30.3°. Point P2 is the point where the magnitude of the first detection signal S1 is 0, and the rotation angle θM is 149.6°. Point P3 is the point where the magnitude of the second detection signal S2 is 0, and the rotation angle θM is 271.3°. Point P4 is the point where the magnitude of the first detection signal S1 and the magnitude of the second detection signal S2 are equal, and the rotation angle θM is 390.3°. Point P5 is the point where the magnitude of the first detection signal S1 is 0, and the rotation angle θM is 509.6°.

[0131] In the time sub-interval from the timing corresponding to point P1 to the timing corresponding to point P2, the rotation angle θM changes by 119.3°. In the time sub-interval from the timing corresponding to point P2 to the timing corresponding to point P3, the rotation angle θM changes by 121.7°. In the time sub-interval from the timing corresponding to point P3 to the timing corresponding to point P4, the rotation angle θM changes by 119°. In the time sub-interval from the timing corresponding to point P4 to the timing corresponding to point P5, the rotation angle θM changes by 119.3°.

[0132] Next, a third modified example of the magnetic sensor 1 will be described. In the third modified example, the configuration of the third resistor R13 of the first bridge circuit 11 is the same as in the first modified example. Also, in the third modified example, both the first reference direction M21 and the third reference direction M23 are 99°. Although not shown in the diagram, both the first magnetization direction m21 and the third magnetization direction m23 are 99°.

[0133] Figure 15 is a waveform diagram showing the waveforms of the first and second detection signals S1 and S2 in the third modified example. In Figure 15, the horizontal axis represents the rotation angle θM of the motor 70, and the vertical axis represents the magnitudes of the first and second detection signals S1 and S2. Also in Figure 15, reference numeral 491 represents the first detection signal S1, and reference numeral 492 represents the second detection signal S2. Furthermore, Figure 15 shows the range in which the rotation angle θM is between 0° and 600°.

[0134] In the range of rotation angle θM shown in Figure 15, the value of the first detection signal S1 is greater than the value of the reference voltage (0 on the vertical axis of Figure 15) when the rotation angle θM satisfies the first case, which is 148.8° < θM < 326.9° or 508.8° < θM ≤ 600°, and less than the value of the reference voltage when the rotation angle θM satisfies the second case, which is 0° ≤ θM < 148.8° or 326.9° < θM < 508.8°. Therefore, in the above range, the first comparator 21 (see Figure 4) outputs a high-level signal when the rotation angle θM is the first case, and outputs a low-level signal when the rotation angle θM is the second case.

[0135] In the range of rotation angle θM shown in Figure 15, the value of the second detection signal S2 is greater than the value of the reference voltage in the third case where the rotation angle θM satisfies 91.7° < θM < 269.8° or 451.7° < θM ≤ 600°, and is less than the value of the reference voltage in the fourth case where the rotation angle θM satisfies 0° ≤ θM < 91.7° or 269.8° < θM < 451.7°. Therefore, in the above range, the second comparator 22 (see Figure 4) outputs a high-level signal when the rotation angle θM is in the third case and outputs a low-level signal when the rotation angle θM is in the fourth case.

[0136] In the range of rotation angles θM shown in Figure 15, the value of the first detection signal S1 is greater than the value of the second detection signal S2 when the rotation angle θM satisfies the fifth case, 0° ≤ θM < 29.9°, 207.3° < θM < 389.9°, or 567.3° < θM ≤ 600°, and is less than the value of the second detection signal S2 when the rotation angle θM satisfies the sixth case, 29.9° < θM < 207.3° or 389.9° < θM < 567.3°. Therefore, in the above range, the third comparator 23 (see Figure 4) outputs a high-level signal when the rotation angle θM is the fifth case and outputs a low-level signal when the rotation angle θM is the sixth case.

[0137] Point P1 shown in Figure 15 is the point where the magnitude of the first detection signal S1 and the magnitude of the second detection signal S2 are equal, and the rotation angle θM is 29.9°. Point P2 is the point where the magnitude of the first detection signal S1 is 0, and the rotation angle θM is 148.8°. Point P3 is the point where the magnitude of the second detection signal S2 is 0, and the rotation angle θM is 269.8°. Point P4 is the point where the magnitude of the first detection signal S1 and the magnitude of the second detection signal S2 are equal, and the rotation angle θM is 389.9°. Point P5 is the point where the magnitude of the first detection signal S1 is 0, and the rotation angle θM is 508.8°.

[0138] In the time sub-interval from the timing corresponding to point P1 to the timing corresponding to point P2, the rotation angle θM changes by 118.9°. In the time sub-interval from the timing corresponding to point P2 to the timing corresponding to point P3, the rotation angle θM changes by 121.0°. In the time sub-interval from the timing corresponding to point P3 to the timing corresponding to point P4, the rotation angle θM changes by 120.1°. In the time sub-interval from the timing corresponding to point P4 to the timing corresponding to point P5, the rotation angle θM changes by 118.9°.

[0139] [Second Embodiment] Next, a second embodiment of the present disclosure will be described. First, the configuration of the magnetic sensor 1 according to this embodiment will be described with reference to Figure 16. Figure 16 is a circuit diagram showing the circuit configuration of the magnetic sensor 1.

[0140] The magnetic sensor 1 according to this embodiment includes a detection circuit 210 instead of the detection circuit 10 in the first embodiment. The detection circuit 210 is configured to detect a rotating magnetic field MF and output a first detection signal S1 and a second detection signal S2.

[0141] The detection circuit 210 includes a bridge circuit 211 which includes a first resistor R211, a second resistor R212, a third resistor R213, and a fourth resistor R214, all composed of multiple MR elements 50. The bridge circuit 211 further includes a power port V21, a ground port G21, a first output port E211, and a second output port E212.

[0142] As shown in Figure 16, the first resistor R211 is located between the power port V21 and the first output port E211 in the circuit configuration. The second resistor R212 is located between the ground port G21 and the first output port E211 in the circuit configuration. The third resistor R213 is located between the ground port G21 and the second output port E212 in the circuit configuration. The fourth resistor R214 is located between the power port V21 and the second output port E212 in the circuit configuration.

[0143] The detection circuit 210 further includes a power terminal 210a, a ground terminal 210b, a first output terminal 210c, a second output terminal 210d, and a bridge circuit 211. Power port V21 is connected to power terminal 210a. Ground port G21 is connected to ground terminal 210b. A predetermined voltage or current is applied to power terminal 210a. Ground terminal 210b is connected to ground.

[0144] The first output port E211 is connected to the first output terminal 210c. The bridge circuit 211 generates a signal corresponding to the potential of the first output port E211 as the first detection signal S1. The first output terminal 210c outputs the first detection signal S1.

[0145] The second output port E212 is connected to the second output terminal 210d. The bridge circuit 211 generates a signal corresponding to the potential of the second output port E212 as the second detection signal S2. The second output terminal 210d outputs the second detection signal S2.

[0146] The first output terminal 210c is connected to the first input terminal 20c of the logic signal generation circuit 20. The second output terminal 210d is connected to the second input terminal 20d of the logic signal generation circuit 20.

[0147] Next, with reference to Figure 16, the magnetization direction of the magnetization fixed layer 52 in each of the first to fourth resistive sections R211 to R214 of the bridge circuit 211 and the sensitivity of each of the first to fourth resistive sections R11 to R14 will be described. In this embodiment, the plurality of MR elements 50 include a plurality of first MR elements 50A3 constituting the first resistive section R211, a plurality of second MR elements 50B3 constituting the second resistive section R212, a plurality of third MR elements 50C3 constituting the third resistive section R213, and a plurality of fourth MR elements 50D3 constituting the fourth resistive section R214.

[0148] Here, the direction obtained by averaging the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple first MR elements 50A3 is called the first magnetization direction m211, the direction obtained by averaging the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple second MR elements 50B3 is called the second magnetization direction m212, the direction obtained by averaging the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple third MR elements 50C3 is called the third magnetization direction m213, and the direction obtained by averaging the magnetization directions of the multiple magnetization fixed layers 52 contained in the multiple fourth MR elements 50D3 is called the fourth magnetization direction m214.

[0149] The first resistor R211 has sensitivity in a first direction parallel to the first reference direction M211. The second resistor R212 has sensitivity in a second direction parallel to the second reference direction M212. The third resistor R213 has sensitivity in a third direction parallel to the third reference direction M213. The fourth resistor R214 has sensitivity in a fourth direction parallel to the fourth reference direction M214. In Figure 16, the first to fourth reference directions M211 to M214 are represented by arrows labeled M211 to M214, respectively. The first reference direction M211 coincides with the first magnetization direction m211, the second reference direction M212 coincides with the second magnetization direction m212, the third reference direction M213 coincides with the third magnetization direction m213, and the fourth reference direction M214 coincides with the fourth magnetization direction m214.

[0150] As shown in Figure 16, the first reference direction M211 is 266°, the second reference direction M212 is 42°, the third reference direction M213 is 328°, and the fourth reference direction M214 is 92°. Although not shown, the first magnetization direction m211 is 266°, the second magnetization direction m212 is 42°, the third magnetization direction m213 is 328°, and the fourth magnetization direction m214 is 92°.

[0151] Next, with reference to Figure 17, the first and second detection signals S1 and S2, and the first to third logic signals Su, Sv, and Sw in this embodiment will be described. Figure 17 is a waveform diagram showing the waveforms of the first and second detection signals S1 and S2. In Figure 17, the horizontal axis represents the rotation angle θM of the motor 70, and the vertical axis represents the magnitude of the first and second detection signals S1 and S2. Also in Figure 17, reference numeral 591 represents the first detection signal S1, and reference numeral 592 represents the second detection signal S2. Figure 17 also shows the range in which the rotation angle θM is between 0° and 600°.

[0152] In the range of rotation angle θM shown in Figure 17, the value of the first detection signal S1 is greater than the value of the reference voltage (0 on the vertical axis of Figure 17) when the rotation angle θM satisfies the first case, which is 0°≦θM<28.2°, 208.3°<θM<388.2°, or 568.3°<θM≦600°, and less than the value of the reference voltage when the rotation angle θM satisfies the second case, which is 28.2°<θM<208.3° or 388.2°<θM<568.3°. Therefore, in the above range, the first comparator 21 outputs a high-level signal when the rotation angle θM is the first case, and outputs a low-level signal when the rotation angle θM is the second case.

[0153] Furthermore, within the range of rotation angle θM shown in Figure 17, the value of the second detection signal S2 is greater than the value of the reference voltage when the rotation angle θM satisfies the third case, which is 149° < θM < 328.9° or 509° < θM ≤ 600°, and less than the value of the reference voltage when the rotation angle θM satisfies the fourth case, which is 0° ≤ θM < 149° or 328.9° < θM < 509°. Therefore, within the above range, the second comparator 22 outputs a high-level signal when the rotation angle θM is the third case, and outputs a low-level signal when the rotation angle θM is the fourth case.

[0154] Furthermore, within the range of rotation angles θM shown in Figure 17, the value of the first detection signal S1 is greater than the value of the second detection signal S2 when the rotation angle θM satisfies the fifth case, 0° ≤ θM < 88.3° or 265.7° < θM < 448.3°, and less than the value of the second detection signal S2 when the rotation angle θM satisfies the sixth case, 88.3° < θM < 265.7° or 448.3° < θM ≤ 600°. Therefore, within the above range, the third comparator 23 outputs a high-level signal when the rotation angle θM is the fifth case and outputs a low-level signal when the rotation angle θM is the sixth case.

[0155] Point P11 in Figure 17 is the point where the magnitude of the first detection signal S1 and the magnitude of the second detection signal S2 are equal, and the rotation angle θM is 88.3°. Point P12 is the point where the magnitude of the first detection signal S1 is 0, and the rotation angle θM is 208.3°. Point P13 is the point where the magnitude of the second detection signal S2 is 0, and the rotation angle θM is 328.9°. Point P14 is the point where the magnitude of the first detection signal S1 and the magnitude of the second detection signal S2 are equal, and the rotation angle θM is 448.3°. The point corresponding to point P15 is the point where the magnitude of the first detection signal S1 is 0, and the rotation angle θM is 568.3°.

[0156] In the time sub-interval from the timing corresponding to point P11 to the timing corresponding to point P12, the rotation angle θM changes by 120.0°. In the time sub-interval from the timing corresponding to point P12 to the timing corresponding to point P13, the rotation angle θM changes by 120.6°. In the time sub-interval from the timing corresponding to point P13 to the timing corresponding to point P14, the rotation angle θM changes by 119.4°. In the time sub-interval from the timing corresponding to point P14 to the timing corresponding to point P15, the rotation angle θM changes by 120.0°.

[0157] Other configurations, operations, and effects in this embodiment are the same as those in the first embodiment.

[0158] This disclosure is not limited to the embodiments described above, and various modifications are possible. For example, each magnetization direction can be any direction, as long as the requirements of the claims are met. The specific direction of each magnetization direction can be explored by the design method of this disclosure.

[0159] Furthermore, at least a portion of the control circuit 121 and the logic signal generation circuit 20 may be implemented by an ASIC or a microcomputer.

[0160] As described above, the magnetic sensor of this disclosure comprises at least one bridge circuit and a plurality of magnetoresistive elements. The at least one bridge circuit includes a first port, a second port, a third port, a fourth port, a first resistive section provided between the first port and the second port, a second resistive section provided between the second port and the third port, a third resistive section provided between the third port and the fourth port, and a fourth resistive section provided between the fourth port and the first port. Each of the plurality of magnetoresistive elements includes a magnetization-fixed layer having magnetization with a fixed direction and a free layer having magnetization with a direction that can change in response to an applied magnetic field. The plurality of magnetoresistive elements include a plurality of first magnetoresistive elements constituting a first resistive section, a plurality of second magnetoresistive elements constituting a second resistive section, a plurality of third magnetoresistive elements constituting a third resistive section, and a plurality of fourth magnetoresistive elements constituting a fourth resistive section. The first, second, and third resistive sections are configured such that a first magnetization direction, which is the average direction of the magnetization directions of multiple magnetization fixed layers included in a plurality of first magnetoresistive elements, a second magnetization direction, which is the average direction of the magnetization directions of multiple magnetization fixed layers included in a plurality of second magnetoresistive elements, and a third magnetization direction, which is the average direction of the magnetization directions of multiple magnetization fixed layers included in a plurality of third magnetoresistive elements, intersect each other at angles other than 0° and 180°.

[0161] In the magnetic sensor of this disclosure, the first resistive section, the second resistive section, and the third resistive section may each have sensitivity in a first direction, sensitivity in a second direction, and sensitivity in a third direction. The first resistive section, the second resistive section, and the third resistive section may be configured such that the first direction, the second direction, and the third direction intersect each other at angles other than 0° and 180°.

[0162] Furthermore, in the magnetic sensor of this disclosure, the fourth resistive portion may be configured such that the fourth magnetization direction, which is the average direction of the magnetization directions of a plurality of magnetization fixed layers included in a plurality of fourth magnetoresistive effect elements, intersects with each of the first magnetization direction, the second magnetization direction, and the third magnetization direction at angles other than 0° and 180°.

[0163] Furthermore, in the magnetic sensor of this disclosure, at least one bridge circuit may be two bridge circuits. At least one of the four resistive sections of the two bridge circuits may be configured such that the fourth magnetization direction, which is the average direction of the magnetization directions of a plurality of magnetization fixed layers included in a plurality of fourth magnetoresistive elements, intersects with the first magnetization direction, the second magnetization direction, and the third magnetization direction at angles other than 0° and 180°.

[0164] Furthermore, in the magnetic sensor of this disclosure, the fourth resistive element may be configured such that the fourth magnetization direction, which is the average direction of the magnetization directions of the plurality of magnetization fixed layers included in the plurality of fourth magnetoresistive elements, is the same direction as any of the first magnetization direction, the second magnetization direction, and the third magnetization direction.

[0165] Furthermore, the magnetic sensor of this disclosure may further include a body that incorporates at least one bridge circuit.

[0166] Furthermore, in the magnetic sensor of this disclosure, at least one bridge circuit is configured to detect a rotating magnetic field whose direction rotates at the detection position and to generate a first detection signal and a second detection signal corresponding to the change in the direction of the magnetic field, and a temporal interval corresponding to one rotation of the direction of the rotating magnetic field may be divided into three or more temporal sub-intervals based on the first detection signal and the second detection signal. At least one bridge circuit may be configured such that the sub-intervals correspond to a change in the direction of the magnetic field within 120° ± 10°. The magnetic sensor of this disclosure may further include a logic signal generation circuit configured to generate a first logic signal, a second logic signal, and a third logic signal having different phases from each other using the first detection signal and the second detection signal.

[0167] The motor device of this disclosure comprises a motor, a motor drive circuit, and a magnetic sensor of this disclosure. The magnetic sensor is connected to the drive circuit.

[0168] The method for manufacturing a magnetic sensor according to this disclosure includes an element formation step for forming a plurality of magnetoresistive elements. The element formation step includes a step of forming a laminated film including a plurality of first magnetic parts which will later become a plurality of magnetization fixed layers and a plurality of second magnetic parts which will later become a plurality of free layers, and a fixing step of fixing the magnetization direction of each of the plurality of first magnetic parts using laser light and an external magnetic field. The fixing step includes a first step of fixing the magnetization direction of a plurality of specific first magnetic parts which will later become a plurality of magnetization fixed layers of a plurality of first magnetoresistive elements, a second step of fixing the magnetization direction of a plurality of specific second magnetic parts which will later become a plurality of magnetization fixed layers of a plurality of second magnetoresistive elements, and a third step of fixing the magnetization direction of a plurality of specific third magnetic parts which will later become a plurality of magnetization fixed layers of a plurality of third magnetoresistive elements. The directions of the external magnetic field in the first process, the second process, and the third process intersect each other at angles other than 0° and 180°.

[0169] A magnetic sensor designed by the design method of the present disclosure comprises a bridge circuit and a plurality of magnetoresistive elements. The bridge circuit includes a first port, a second port, a third port, a fourth port, a first resistive section between the first port and the second port, a second resistive section between the second port and the third port, a third resistive section between the third port and the fourth port, and a fourth resistive section between the fourth port and the first port. Each of the plurality of magnetoresistive elements includes a magnetization-fixed layer having a magnetization with a fixed direction and a free layer having a magnetization with a direction changeable in response to an applied magnetic field. The plurality of magnetoresistive elements include a plurality of first magnetoresistive elements constituting a first resistive section, a plurality of second magnetoresistive elements constituting a second resistive section, a plurality of third magnetoresistive elements constituting a third resistive section, and a plurality of fourth magnetoresistive elements constituting a fourth resistive section. The bridge circuit is configured to detect a rotating magnetic field whose direction is rotating at the detection location.

[0170] The design method of the present disclosure includes setting the magnetization directions of a plurality of magnetization stationary layers contained in each of a plurality of first magnetoresistive elements, a plurality of second magnetoresistive elements, a plurality of third magnetoresistive elements, and a plurality of fourth magnetoresistive elements, such that the bridge circuit generates a first detection signal and a second detection signal corresponding to a change in the direction of a rotating magnetic field, respectively, and setting the magnetization directions of the plurality of magnetization stationary layers such that a temporal interval corresponding to one rotation of the direction of the rotating magnetic field is divided into three or more temporal sub-intervals based on the first detection signal and the second detection signal. [Explanation of Symbols]

[0171] 1…Magnetic sensor, 2…Main unit, 3…First chip, 4…Second chip, 5…Circuit board, 10…Detection circuit, 10a1,10a2…Power terminals, 10b1,10b2…Ground terminals, 10c…First output terminal, 10d…Second output terminal, 11…First bridge circuit, 12…Second bridge circuit, 13…First differential amplifier, 14…Second differential amplifier, 20…Logic signal generation circuit, 20a…Power terminal, 20b…Ground terminal, 20c…First input terminal, 20d…Second Input terminal, 20e...First output terminal, 20f...Second output terminal, 20g...Third output terminal, 21...First comparator, 21a...First input terminal, 21b...Second input terminal, 21c...Output terminal, 22...Second comparator, 22a...First input terminal, 22b...Second input terminal, 22c...Output terminal, 23...Third comparator, 23a...First input terminal, 23b...Second input terminal, 23c...Output terminal, 24,25...Resistors, 41,42...Wires, 43...Leads, 44...Sealing rods 50…MR element, 51…Antiferromagnetic layer, 52…Magnetic fixed layer, 53…Gap layer, 54…Free layer, 61…Lower electrode, 62…Upper electrode, 70…Motor, 71…Rotor, 72…Stator, 73u…First coil, 73v…Second coil, 73w…Third coil, 74…Magnetic field generator, 100…Motor device, 120…Drive circuit, 121…Control circuit, 122…Output circuit, C…Rotation axis, DR…Reference direction, E11, E21…First output port, E12, E22…Second output Force port, G1, G2... Ground port, M11~M14, M21~M24... Reference direction, m11~m14, m21~m24... Magnetization direction, MF... Rotating magnetic field, PL... Reference plane, PR... Reference position, R11~R14, R21~R24... Resistance section, S1... First detection signal, S2... Second detection signal, Sc... Speed ​​command, Su... First logic signal, Sv... Second logic signal, Sw... Third logic signal, V1, V2... Power port, θ... Rotating magnetic field angle, θM... Rotation angle.

Claims

1. A magnetic sensor comprising at least one bridge circuit and a plurality of magnetoresistive elements, The at least one bridge circuit is, The first port and The second port and The third port and The fourth port and A first resistor is provided between the first port and the second port, A second resistor is provided between the second port and the third port, A third resistor is provided between the third port and the fourth port, A fourth resistor is provided between the fourth port and the first port. Includes, Each of the plurality of magnetoresistive elements includes a magnetization-fixed layer having magnetization with a fixed direction and a free layer having magnetization with a direction that can change according to the applied magnetic field. The plurality of magnetoresistive elements include a plurality of first magnetoresistive elements constituting the first resistive portion, a plurality of second magnetoresistive elements constituting the second resistive portion, a plurality of third magnetoresistive elements constituting the third resistive portion, and a plurality of fourth magnetoresistive elements constituting the fourth resistive portion. A magnetic sensor characterized in that the first resistive portion, the second resistive portion, and the third resistive portion are configured such that a first magnetization direction, which is the average direction of the magnetization directions of a plurality of magnetization fixed layers included in the plurality of first magnetoresistive effect elements, a second magnetization direction, which is the average direction of the magnetization directions of a plurality of magnetization fixed layers included in the plurality of second magnetoresistive effect elements, and a third magnetization direction, which is the average direction of the magnetization directions of a plurality of magnetization fixed layers included in the plurality of third magnetoresistive effect elements, intersect each other at angles other than 0° and 180°.

2. The first resistor, the second resistor, and the third resistor each have sensitivity in a first direction, sensitivity in a second direction, and sensitivity in a third direction, The magnetic sensor according to claim 1, characterized in that the first resistive portion, the second resistive portion, and the third resistive portion are configured such that the first direction, the second direction, and the third direction intersect each other at angles other than 0° and 180°.

3. The magnetic sensor according to claim 1, characterized in that the fourth resistive portion is configured such that the fourth magnetization direction, which is the average direction of the magnetization directions of the plurality of magnetization fixed layers included in the plurality of fourth magnetoresistive effect elements, intersects with each of the first magnetization direction, the second magnetization direction, and the third magnetization direction at angles other than 0° and 180°.

4. The aforementioned at least one bridge circuit is two bridge circuits, The magnetic sensor according to claim 1, characterized in that the fourth resistive portion of at least one of the two bridge circuits is configured such that the fourth magnetization direction, which is the average direction of the magnetization directions of the plurality of magnetization fixed layers included in the plurality of fourth magnetoresistive elements, intersects with each of the first magnetization direction, the second magnetization direction, and the third magnetization direction at angles other than 0° and 180°.

5. The magnetic sensor according to claim 1, characterized in that the fourth resistive portion is configured such that the fourth magnetization direction, which is the average direction of the magnetization directions of the plurality of magnetization fixed layers included in the plurality of fourth magnetoresistive effect elements, is the same direction as any of the first magnetization direction, the second magnetization direction, and the third magnetization direction.

6. Furthermore, the magnetic sensor according to claim 1 is characterized by comprising a main body that incorporates at least one of the bridge circuits.

7. The magnetic sensor according to claim 1, wherein the at least one bridge circuit is configured to detect a rotating magnetic field whose direction rotates at the detection position and to generate a first detection signal and a second detection signal corresponding to the change in the direction of the magnetic field, and a temporal interval corresponding to one rotation of the direction of the rotating magnetic field is divided into three or more temporal sub-intervals based on the first detection signal and the second detection signal.

8. The magnetic sensor according to claim 7, characterized in that the at least one bridge circuit is configured such that the sub-section corresponds to a change of within 120° ± 10° in the direction of the magnetic field.

9. Furthermore, the magnetic sensor according to claim 7 is characterized by comprising a logic signal generation circuit configured to generate a first logic signal, a second logic signal, and a third logic signal having different phases from each other using the first detection signal and the second detection signal.

10. Motor and, The motor drive circuit and A magnetic sensor as described in any one of claims 1 to 9, The motor device is characterized in that the magnetic sensor is connected to the drive circuit.

11. A method for manufacturing a magnetic sensor according to any one of claims 1 to 9, The process includes an element formation step for forming the plurality of magnetoresistive effect elements, The element formation step includes forming a laminated film which includes a plurality of first magnetic portions that will later become a plurality of magnetized fixed layers and a plurality of second magnetic portions that will later become a plurality of free layers. The process includes a fixing step of fixing the magnetization direction of each of the multiple first magnetic parts using laser light and an external magnetic field, The fixing step includes a first step of fixing the magnetization direction of a plurality of specific first magnetic parts among the plurality of first magnetic parts which will later become a plurality of magnetization fixing layers of the plurality of first magnetoresistive elements; a second step of fixing the magnetization direction of a plurality of specific second magnetic parts among the plurality of first magnetic parts which will later become a plurality of magnetization fixing layers of the plurality of second magnetoresistive elements; and a third step of fixing the magnetization direction of a plurality of specific third magnetic parts among the plurality of first magnetic parts which will later become a plurality of magnetization fixing layers of the plurality of third magnetoresistive elements. A method for manufacturing a magnetic sensor, characterized in that the direction of the external magnetic field in the first step, the direction of the external magnetic field in the second step, and the direction of the external magnetic field in the third step intersect each other at angles other than 0° and 180°.

12. A method for designing a magnetic sensor comprising a bridge circuit and multiple magnetoresistive elements, The aforementioned bridge circuit is The first port and The second port and The third port and The fourth port and A first resistor is provided between the first port and the second port, A second resistor is provided between the second port and the third port, A third resistor is provided between the third port and the fourth port, A fourth resistor is provided between the fourth port and the first port. Includes, Each of the plurality of magnetoresistive elements includes a magnetization-fixed layer having magnetization with a fixed direction and a free layer having magnetization with a direction that can change according to the applied magnetic field. The plurality of magnetoresistive elements include a plurality of first magnetoresistive elements constituting the first resistive portion, a plurality of second magnetoresistive elements constituting the second resistive portion, a plurality of third magnetoresistive elements constituting the third resistive portion, and a plurality of fourth magnetoresistive elements constituting the fourth resistive portion. The bridge circuit is configured to detect a rotating magnetic field whose direction rotates at the detection position. The aforementioned design method is The magnetization directions of the multiple magnetization fixed layers included in each of the multiple first magnetoresistive elements, the multiple second magnetoresistive elements, the multiple third magnetoresistive elements, and the multiple fourth magnetoresistive elements are set such that the bridge circuit generates a first detection signal and a second detection signal corresponding to a change in the direction of the rotating magnetic field, respectively. The magnetization direction of the plurality of magnetized fixed layers is set such that a time interval corresponding to one rotation in the direction of the rotating magnetic field is divided into three or more time sub-intervals based on the first detection signal and the second detection signal. A method for designing a magnetic sensor, characterized by including the following:

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