Magnetic sensor, position detection device, and electronic equipment

Abstract

The magnetic sensor of the present invention comprises: a magnetic field converter that outputs an input magnetic field in a first direction as an output magnetic field in a second direction orthogonal thereto; a magnetic field detector located at a position where the output magnetic field can be applied; and a magnetic shield that shields the external magnetic field in a third direction orthogonal to the first and second directions. When viewed along the first direction, the magnetic field converter has a length in the third direction that is longer than its length in the second direction. The magnetic shield is located at a position overlapping the magnetic field converter and the magnetic field detector. The magnetic field detector comprises a Wheatstone bridge circuit formed by connecting a first bridge circuit including the first and second magnetic field detectors in parallel with a second bridge circuit including the third and fourth magnetic field detectors. The first to fourth magnetic field detectors include two magnetoresistive elements each having a magnetoresistive effect element having a magnetized fixed layer with mutually different magnetization directions.

Description

Technical Field

[0001] The present invention relates to a magnetic sensor, a position detection device and an electronic device. Background Art

[0002] In recent years, physical quantity detection devices (position detection devices) for detecting physical quantities (e.g., the position or amount of movement (amount of change) resulting from the rotational or linear movement of a moving object) have been used in various applications. Known physical quantity detection devices include a device that includes a magnetic sensor that detects changes in an external magnetic field and a magnetic field generator (e.g., a magnet) that changes its relative position relative to the magnetic sensor. The magnetic sensor outputs a sensor signal corresponding to the change in the external magnetic field.

[0003] Known magnetic sensors include those in which a magnetic sensor element for detecting a magnetic field to be detected is provided on a substrate. As such magnetic sensor elements, magnetoresistive elements (GMR elements, TMR elements, etc.) whose resistance changes according to changes in an external magnetic field are used.

[0004] The magnetoresistance element is constructed by a stacked structure comprising at least a free layer whose magnetization direction changes in response to an external magnetic field, a fixed magnetization layer whose magnetization direction is fixed, and a nonmagnetic layer interposed between the free layer and the fixed magnetization layer. In a magnetoresistance element having this structure, the resistance of the magnetoresistance element is determined by the angle between the magnetization directions of the free layer and the fixed magnetization layer. Furthermore, as the magnetization direction of the free layer changes in response to an external magnetic field, the resulting change in the angle between the magnetization directions of the free layer and the fixed magnetization layer causes the resistance of the magnetoresistance element to change. This change in resistance outputs a sensor signal corresponding to the change in the external magnetic field. Magnetoresistance elements disposed on a substrate are often constructed to be sensitive to magnetic fields in a direction parallel to the substrate surface.

[0005] On the other hand, magnetic sensors are also required to detect a magnetic field perpendicular to the substrate surface using a magnetoresistive element disposed on the substrate (see Patent Document 1). Such magnetic sensors can be used to detect the position of a magnet. In such magnetic sensors, a soft magnetic material is provided to apply the magnetic field component perpendicular to the substrate surface, among the components of the magnetic field generated by the magnet, to the magnetoresistive element. This soft magnetic material converts the perpendicular magnetic field component generated by the magnet into a magnetic field component parallel to the substrate surface, to which the magnetoresistive element is sensitive. This converted magnetic field component is then applied to the magnetoresistive element.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-129697 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] In the magnetic sensor described above, the magnetic field generated by the magnet includes the aforementioned perpendicular magnetic field component and a horizontal magnetic field component parallel to the substrate surface. When this horizontal magnetic field component is applied to the magnetoresistive element, the detection accuracy of the magnetic sensor may be reduced. To address this technical issue, a magnetic shield can be used to block the horizontal magnetic field component.

[0011] However, the aforementioned magnetic shield cannot completely block the horizontal magnetic field component; a portion of the horizontal magnetic field component is transmitted through it. Consequently, the transmitted horizontal magnetic field component affects the signal output from the magnetic sensor. Specifically, the horizontal magnetic field component that transmits the magnetic shield through the magnetic sensor causes an offset in the output of the magnetic sensor or a change in the midpoint potential, potentially reducing the detection accuracy of the magnetic sensor.

[0012] In view of the above problems, an object of the present invention is to provide a magnetic sensor, a position detection device, and an electronic device that suppress fluctuations in midpoint potential and improve detection accuracy.

[0013] Technical solutions to solve problems

[0014] To solve the above-mentioned problems, the present invention provides a magnetic sensor comprising: a magnetic field converter that receives an input magnetic field input along a first direction and outputs an output magnetic field along a second direction orthogonal to the first direction; a magnetic field detector provided at a position where the output magnetic field can be applied; and a magnetic shield that shields an external magnetic field along the second direction. When viewed along the first direction, the magnetic field converter has a shape whose length in a third direction orthogonal to both the first and second directions is longer than its length in the second direction. When viewed along the first direction, the magnetic shield is provided at a position overlapping the magnetic field converter and the magnetic field detector. The magnetic field detector is configured by a Wheatstone bridge circuit in which a first bridge circuit including first and second magnetic field detectors is connected in parallel with a second bridge circuit including third and fourth magnetic field detectors. Each of the first to fourth magnetic field detectors includes a first magnetoresistive section and a second magnetoresistive section, and each of the first to fourth magnetic field detectors includes a magnetoresistive element having magnetization pinned layers having mutually different magnetization directions.

[0015] In the magnetic sensor described above, the first magnetic resistance portion and the second magnetic resistance portion included in each of the first to fourth magnetic field detection portions may be connected in parallel or in series.

[0016] In the above-mentioned magnetic sensor, it may also be that the Wheatstone bridge circuit includes a power supply port, a ground port, a first output port and a second output port, the first magnetic field detection unit is arranged between the power supply port and the first output port, the second magnetic field detection unit is arranged between the first output port and the ground port, the third magnetic field detection unit is arranged between the power supply port and the second output port, and the fourth magnetic field detection unit is arranged between the second output port and the ground port, the first magnetic resistance unit and the second magnetic resistance unit included in two of the first magnetic field detection unit, the second magnetic field detection unit, the third magnetic field detection unit and the fourth magnetic field detection unit are connected in parallel, and the first magnetic resistance unit and the second magnetic resistance unit included in the other two magnetic field detection units are connected in series.

[0017] The first and second magnetoresistive sections included in each of the first to fourth magnetic field detection sections each include a plurality of magnetoresistive elements. The number of magnetoresistive elements included in the first magnetoresistive section may be the same as the number of magnetoresistive elements included in the second magnetoresistive section, or the number of magnetoresistive elements included in the first magnetoresistive section may be greater than the number of magnetoresistive elements included in the second magnetoresistive section. The ratio of the number of magnetoresistive elements included in the first magnetoresistive section to the number of magnetoresistive elements included in the second magnetoresistive section may be set to 2:1 to 4:1.

[0018] The magnetization direction of the magnetization pinned layer of the magnetoresistive element included in the first magnetoresistive portion and the magnetization direction of the magnetization pinned layer of the magnetoresistive element included in the second magnetoresistive portion may be antiparallel to each other and oriented along the second direction. When viewed along the first direction, the magnetic shield may have a shape whose maximum length in the third direction is longer than its maximum length in the second direction. Multiple magnetic converters may be arranged in parallel along the second direction. The magnetic shield may include a first magnetic shield and a second magnetic shield, and the magnetic field converter and magnetic field detector may be disposed between the first and second magnetic shields in the first direction. The magnetic shield may be located on one side or the other side of the magnetic field converter and magnetic field detector along the first direction. When viewed along the first direction, the first and second magnetoresistive portions included in each of the first to fourth magnetic field detectors may be arranged in line-symmetrical positions about an axis along the longitudinal direction of the magnetic field converter, the axis passing through the center of the lateral direction of the magnetic field converter. The magnetoresistive element may be either a TMR element or a GMR element.

[0019] The present invention provides a position detection device, characterized in that it comprises: the magnetic sensor; a magnetic field generating unit that generates the input magnetic field; a substrate on which the magnetic sensor device is provided, and the magnetic field generating unit is supported by the substrate in a manner that allows relative movement along at least one of the second direction and the third direction relative to the substrate.

[0020] The present invention provides an electronic device including the position detection device.

[0021] Effects of the Invention

[0022] According to the present invention, it is possible to provide a magnetic sensor, a position detection device, and an electronic device that suppress fluctuations in midpoint potential and improve detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a perspective view schematically showing the configuration of a camera module including the magnetic sensor device according to one embodiment of the present invention.

[0024] Figure 2 It is schematically represented Figure 1 A schematic diagram of the internal structure of the camera module shown.

[0025] Figure 3 Yes Figure 1 A perspective view of the driving device of the camera module is shown.

[0026] Figure 4 Yes Figure 3 A perspective view of multiple coils of the driving device is shown.

[0027] Figure 5A Yes Figure 3 A cross-sectional view of the main parts of the drive device is shown.

[0028] Figure 5B Yes Figure 3 A cross-sectional view of the main parts of the drive device is shown.

[0029] Figure 6 This is a perspective view showing the main parts of a magnetic sensor device according to one embodiment of the present invention.

[0030] Figure 7 It is a perspective view showing a schematic structure of a magnetic sensor according to one embodiment of the present invention.

[0031] Figure 8A This is a plan view schematically showing the structure of a magnetic sensor according to one embodiment of the present invention.

[0032] Figure 8B This is a plan view schematically showing the structure of a magnetic sensor according to one embodiment of the present invention.

[0033] Figure 8C This is a plan view schematically showing the structure of a magnetic sensor according to one embodiment of the present invention.

[0034] Figure 8D This is a plan view schematically showing the structure of a magnetic sensor according to one embodiment of the present invention.

[0035] Figure 9 This is a side view schematically showing the structure of a magnetic sensor according to one embodiment of the present invention.

[0036] Figure 10 This is a side view schematically showing the structure of a magnetic sensor according to one embodiment of the present invention.

[0037] Figure 11 This is a perspective view schematically showing the structure of a magnetoresistive effect element according to one embodiment of the present invention.

[0038] Figure 12 It is a perspective view showing a schematic configuration of a magnetic field detection unit according to one embodiment of the present invention.

[0039] Figure 13A This is a circuit diagram showing a circuit configuration of a magnetic field detection unit according to one embodiment of the present invention.

[0040] Figure 13B This is a circuit diagram showing a circuit configuration of a magnetic field detection unit according to one embodiment of the present invention.

[0041] Figure 13C This is a circuit diagram showing a circuit configuration of a magnetic field detection unit according to one embodiment of the present invention.

[0042] Figure 13D This is a circuit diagram showing a circuit configuration of a magnetic field detection unit according to one embodiment of the present invention.

[0043] Figure 14A These are explanatory diagrams for explaining the magnetization directions of the free layer and the magnetization pinned layer in the initial state of the magnetoresistive element according to one embodiment of the present invention.

[0044] Figure 14B These are explanatory diagrams for explaining the magnetization directions of the free layer and the magnetization pinned layer in the initial state of the magnetoresistive element according to one embodiment of the present invention.

[0045] Figure 14C These are explanatory diagrams for explaining the magnetization directions of the free layer and the magnetization pinned layer in the initial state of the magnetoresistive element according to one embodiment of the present invention.

[0046] Figure 14DThese are explanatory diagrams for explaining the magnetization directions of the free layer and the magnetization pinned layer in the initial state of the magnetoresistive element according to one embodiment of the present invention.

[0047] Figure 15A These are explanatory diagrams for explaining the magnetization directions of the free layer and the magnetization pinned layer when the second magnetic field component is applied to the magnetoresistive element according to one embodiment of the present invention.

[0048] Figure 15B These are explanatory diagrams for explaining the magnetization directions of the free layer and the magnetization pinned layer when the second magnetic field component is applied to the magnetoresistive element according to one embodiment of the present invention.

[0049] Figure 15C These are explanatory diagrams for explaining the magnetization directions of the free layer and the magnetization pinned layer when the second magnetic field component is applied to the magnetoresistive element according to one embodiment of the present invention.

[0050] Figure 15D These are explanatory diagrams for explaining the magnetization directions of the free layer and the magnetization pinned layer when the second magnetic field component is applied to the magnetoresistive element according to one embodiment of the present invention.

[0051] Figure 16A These are explanatory diagrams for explaining the magnetization directions of the free layer and the magnetization pinned layer when the second magnetic field component and the bias magnetic field component are applied to the magnetoresistive element according to one embodiment of the present invention.

[0052] Figure 16B These are explanatory diagrams for explaining the magnetization directions of the free layer and the magnetization pinned layer when the second magnetic field component and the bias magnetic field component are applied to the magnetoresistive element according to one embodiment of the present invention.

[0053] Figure 16C These are explanatory diagrams for explaining the magnetization directions of the free layer and the magnetization pinned layer when the second magnetic field component and the bias magnetic field component are applied to the magnetoresistive element according to one embodiment of the present invention.

[0054] Figure 16D These are explanatory diagrams for explaining the magnetization directions of the free layer and the magnetization pinned layer when the second magnetic field component and the bias magnetic field component are applied to the magnetoresistive element according to one embodiment of the present invention.

[0055] Figure 17A This is a graph showing the differential output obtained in Test Example 1.

[0056] Figure 17B This is a graph showing the output potentials obtained in Test Example 1.

[0057] Figure 18A This is a graph showing the differential output obtained in Experimental Example 2.

[0058] Figure 18B This is a graph showing the output potential obtained in Test Example 2.

[0059] Figure 19A This is a graph showing the differential output obtained in Experimental Example 3.

[0060] Figure 19B This is a graph showing the output potentials obtained in Test Example 3.

[0061] Figure 20A This is a graph showing the differential output obtained in Test Example 4.

[0062] Figure 20B This is a graph showing the output potentials obtained in Test Example 4.

[0063] Figure 21A This is a graph showing the sensitivity of the magnetic sensor of Sample 1 obtained in Test Example 5.

[0064] Figure 21B This is a graph showing the sensitivity of the magnetic sensor of Sample 2 obtained in Test Example 5. DETAILED DESCRIPTION

[0065] Embodiments of the present invention will be described with reference to the accompanying drawings.

[0066] In the magnetic sensor device of this embodiment, "X direction, Y direction, and Z direction" are specified in some drawings as needed. Here, the X direction and the Y direction are the first surface 104A and the second surface 104B of the substrate 104 in this embodiment (see Figure 2 ) are mutually orthogonal directions within planes that are actually parallel, and the Z direction is the thickness direction of the substrate 104 (a direction orthogonal to the first surface 104A and the second surface 104B of the substrate 104).

[0067] The camera module 100 of this embodiment is a camera module that constitutes a portion of a camera for a smartphone equipped with an optical shake correction mechanism and an autofocus mechanism, and is used in combination with an image sensor 200 using a CMOS or the like (see FIG. Figure 1 and Figure 2 ).

[0068] The camera module 100 includes a driving device, a lens 102, a housing 103, and a substrate 104 (see FIG. Figure 1 and Figure 2 The drive device has the function of moving the lens 102. The drive device includes the magnetic sensor device of this embodiment. The housing 103 has the function of protecting the drive device. The substrate 104 has a first surface 104A and a second surface 104B opposite thereto.

[0069] The lens 102 is disposed above the first surface 104A of the substrate 104, with its optical axis parallel to the Z direction. The substrate 104 has an opening (not shown) through which light passing through the lens 102 passes. The camera module 100 is aligned with respect to the image sensor 200 so that light passing through the lens 102 and the opening of the substrate 104 is incident on the image sensor 200.

[0070] The driving device includes a first holding member 105, a second holding member 106, a plurality of first conductive wires 107, and a plurality of second conductive wires 108 (see Figure 2 The second holding member 106 is a holding member that holds the lens 102 and may have, for example, a cylindrical shape in which the lens 102 can be fitted.

[0071] The second holding member 106 is configured to be repositionable relative to the first holding member 105 in one direction, specifically, in a direction parallel to the optical axis (Z direction) of the lens 102. In this embodiment, the first holding member 105 has a box-like shape capable of accommodating the lens 102 and the second holding member 106. A plurality of second wires 108 connect the first holding member 105 and the second holding member 106, supporting the second holding member 106 so that it can move relative to the first holding member 105 in the Z direction.

[0072] The first holding member 105 is disposed above the first surface 104A of the substrate 104 so as to be positionally adjustable relative to the substrate 104 in at least one of the X and Y directions. A plurality of first conductive wires 107 connect the substrate 104 and the first holding member 105, supporting the first holding member 105 so as to enable relative movement relative to the substrate 104 in at least one of the X and Y directions. When the relative position of the first holding member 105 relative to the substrate 104 changes, the relative position of the second holding member 106 relative to the substrate 104 also changes.

[0073] The driving device includes a plurality of magnets (first to eighth magnets 21 to 28) and a plurality of coils (first to sixth coils 31 to 36) (see Figure 1 and Figure 3 The first magnet 21 and the second magnet 22 are arranged so as to sandwich the lens 102 therebetween along the Y direction. The third magnet 23 and the fourth magnet 24 are arranged so as to sandwich the lens 102 therebetween along the X direction. The fifth to eighth magnets 25 to 28 are arranged above the first to fourth magnets 21 to 24, respectively (in the +Z direction). The first to eighth magnets 21 to 28 are fixed to the first holding member 105.

[0074] The first magnet 21, the second magnet 22, the fifth magnet 25, and the sixth magnet 26 each have a rectangular parallelepiped shape with the longitudinal direction facing the X direction. The third magnet 23, the fourth magnet 24, the seventh magnet 27, and the eighth magnet 28 each have a rectangular parallelepiped shape with the longitudinal direction facing the Y direction (see Figure 1 and Figure 3 The magnetization direction H of the first magnet 21 (refer to Figure 6 The magnetization directions of the first and second magnets 23 and 28 are in the +X direction, and the magnetization directions of the fourth and seventh magnets 24 and 27 are in the -X direction.

[0075] The first coil 31 is disposed between the first magnet 21 and the substrate 104, and the second coil 32 is disposed between the second magnet 22 and the substrate 104 (see Figure 2 The third coil 33 is positioned between the third magnet 23 and the substrate 104, and the fourth coil 34 is positioned between the fourth magnet 24 and the substrate 104. The fifth coil 35 is positioned between the first and fifth magnets 21 and 25 and the lens 102, and the sixth coil 36 is positioned between the second and sixth magnets 22 and 26 and the lens 102. The first to fourth coils 31 to 34 are fixed to the first surface 104A of the substrate 104, and the fifth and sixth coils 35 and 36 are positioned on the second holding member 106.

[0076] The first coil 31 is mainly applied with the magnetic field generated by the first magnet 21 , the second coil 32 is mainly applied with the magnetic field generated by the second magnet 22 , the third coil 33 is mainly applied with the magnetic field generated by the third magnet 23 , and the fourth coil 34 is mainly applied with the magnetic field generated by the fourth magnet 24 .

[0077] The fifth coil 35 includes a first conductor portion 351 extending in the X direction along the first magnet 21, a second conductor portion 352 extending in the X direction along the fifth magnet 25, and two third conductor portions 353 connecting one end of the first conductor portion 351 and the other end of the second conductor portion 352 in the Z direction (see FIG. Figure 4 The sixth coil 36 includes a first conductor portion 361 extending in the X direction along the second magnet 22, a second conductor portion 362 extending in the X direction along the sixth magnet 26, and two third conductor portions 363 connecting one end of the first conductor portion 361 and the other end of the second conductor portion 362 in the Z direction (see Figure 4 ).

[0078] The first conductor portion 351 of the fifth coil 35 is primarily applied with the +Y-direction component of the magnetic field generated by the first magnet 21. The second conductor portion 352 of the fifth coil is primarily applied with the -Y-direction component of the magnetic field generated by the fifth magnet 25. The first conductor portion 361 of the sixth coil 36 is primarily applied with the -Y-direction component of the magnetic field generated by the second magnet 22. The second conductor portion 362 of the sixth coil 36 is primarily applied with the +Y-direction component of the magnetic field generated by the sixth magnet 26.

[0079] The driving device includes a magnetic sensor 10 fixed to the substrate 104 on the inner side of either the first coil 31 or the second coil 32, and a magnetic sensor 10 fixed to the substrate 104 on the inner side of either the third coil 33 or the fourth coil 34. In this embodiment, the two magnetic sensors 10 are respectively arranged on the inner side of the first coil 31 and the inner side of the fourth coil 34 (see Figure 5A 、 Figure 5B In order to reduce the influence of vibration, the two magnetic sensors 10 output sensor signals for changing the position of the lens 102.

[0080] The magnetic sensor 10 disposed inside the first coil 31 detects the magnetic field generated by the first magnet 21 and outputs a sensor signal corresponding to the position of the first magnet 21. The magnetic sensor 10 disposed inside the fourth coil 34 detects the magnetic field generated by the fourth magnet 24 and outputs a sensor signal corresponding to the position of the fourth magnet 24. The structure of each magnetic sensor 10 will be described later.

[0081] The driving device includes a magnet 41 and a magnetic sensor 42 (see Figure 1 and Figure 3 Magnetic sensor 42 is used to detect the position of lens 102 during automatic focusing. Magnetic sensor 42 is fixed to first surface 104A of substrate 104 near end surface 21A of first magnet 21 and end surface 24A of fourth magnet 24. Magnetic sensor 42 may include a magnetoresistive element such as a Hall effect element, an AMR element, a GMR element, or a TMR element.

[0082] The magnet 41 is fixed to the second holding member 106 above the magnetic sensor 42 and has a rectangular parallelepiped shape. When the relative position of the second holding member 106 with respect to the first holding member 105 changes in a direction parallel to the Z direction, the relative position of the magnet 41 with respect to the first holding member 105 also changes in a direction parallel to the Z direction.

[0083] Here, the operation of the drive device will be described.

[0084] The drive device forms part of the optical shake correction mechanism and the autofocus mechanism. The drive device, the optical shake correction mechanism, and the autofocus mechanism are controlled by a control unit (not shown) outside the camera module 100.

[0085] The optical image stabilization mechanism is configured to detect camera shake using, for example, a gyroscopic sensor external to the camera module 100. When the optical image stabilization mechanism detects camera shake, the control unit controls the drive device so that the relative position of the lens 102 relative to the substrate 104 changes in accordance with the type of camera shake. This stabilizes the absolute position of the lens 102, reducing the effects of camera shake. Furthermore, the relative position of the lens 102 relative to the substrate 104 changes in both the X and Y directions depending on the type of camera shake.

[0086] The autofocus mechanism is configured to detect the state of focusing on a subject using, for example, the image sensor 200 or an autofocus sensor. The control unit uses the drive device to change the relative position of the lens 102 with respect to the substrate 104 in the Z direction so that the subject is in focus. This allows automatic focusing on the subject.

[0087] The operation of the drive device related to the optical shake correction mechanism will be described.

[0088] When the control unit applies current to the first coil 31 and the second coil 32, the interaction between the magnetic fields generated by the first and second magnets 21 and 22 and the magnetic fields generated by the first and second coils 31 and 32 causes the first holding member 105, to which the first and second magnets 21 and 22 are fixed, to move in the Y direction. Consequently, the lens 102 also moves in the Y direction. Furthermore, when the control unit applies current to the third and fourth coils 33 and 34, the interaction between the magnetic fields generated by the third and fourth magnets 23 and 24 and the magnetic fields generated by the third and fourth coils 33 and 34 causes the first holding member 105, to which the third and fourth magnets 23 and 24 are fixed, to move in the X direction. Consequently, the lens 102 also moves in the X direction. The control unit detects the position of the lens 102 based on signals corresponding to the positions of the first and fourth magnets 21 and 24 detected by the two magnetic sensors 10.

[0089] The operation of the driving device related to the autofocus mechanism will be described.

[0090] To move the relative position of lens 102 with respect to substrate 104 in the Z direction, the control unit applies current to fifth coil 35, causing current to flow through first conductor 351 in the +X direction and through second conductor 352 in the -X direction. Current is also applied to sixth coil 36, causing current to flow through first conductor 361 in the -X direction and through second conductor 362 in the +X direction. These currents and the magnetic fields generated by first magnet 21, second magnet 22, fifth magnet 25, and sixth magnet 26 exert a Z-directional Lorentz force on first conductor 351 and second conductor 352 of fifth coil 35 and first conductor 361 and second conductor 362 of sixth coil 36. This causes second holding member 106, which secures fifth coil 35 and sixth coil 36, to move in the Z direction. Consequently, lens 102 also moves in the Z direction. When moving the relative position of the lens 102 to the substrate 104 in the −Z direction, the control unit may apply a current in the opposite direction to that in the case of moving the lens 102 in the Z direction to the fifth coil 35 and the sixth coil 36 .

[0091] When the relative position of lens 102 with respect to substrate 104 changes in the Z direction, the relative position of magnet 41 with respect to magnetic sensor 42 also changes in the Z direction. Magnetic sensor 42 detects at least the magnetic field generated by magnet 41 and generates a signal corresponding to the position of magnet 41. The control unit detects the position of lens 102 based on the signal generated by magnetic sensor 42.

[0092] Next, a schematic configuration of the magnetic sensor device according to this embodiment will be described.

[0093] The magnetic sensor device of this embodiment includes a magnetic sensor 10 disposed inside a first coil 31 and a first magnet 21 serving as a magnetic field generator. Furthermore, the magnetic sensor device of this embodiment includes a magnetic sensor 10 disposed inside a second coil 32 and a second magnet 22 serving as a magnetic field generator. The following description uses as an example a magnetic sensor device including the magnetic sensor 10 and the first magnet 21 disposed inside the first coil 31. However, the following description also applies to a magnetic sensor device including the magnetic sensor 10 and the second magnet 22 disposed inside the second coil 32.

[0094] In the magnetic sensor device, the magnetic sensor 10 and the first magnet 21 are configured so that a partial magnetic field, which is a portion of the magnetic field generated by the first magnet 21, can be applied to the magnetic sensor 10. The partial magnetic field generated by the first magnet 21 includes, for example, a first magnetic field component H1 parallel to the Z direction as the first direction (see Figure 6) and a magnetic field component parallel to the Y direction as the second direction. In this embodiment, the magnetization direction H of the first magnet 21 is parallel to the Y direction. Therefore, as described later, a portion of the magnetic field component parallel to the Y direction included in the partial magnetic field generated by the first magnet 21 can be applied to the magnetic sensor 10 as a bias magnetic field component Hb (see Figure 6 ).

[0095] As described above, the magnetic sensor 10 is fixed to the substrate 104, and the first magnet 21 is fixed to the first holding member 105. When the position of the first holding member 105 relative to the substrate 104 changes in the Y direction, the relative position of the first magnet 21 with respect to the magnetic sensor 10 also changes in the Y direction. The output from the magnetic sensor 10 corresponds to the relative position of the first magnet 21 with respect to the magnetic sensor 10 in the Y direction.

[0096] The magnetic sensor 10 and the first magnet 21 are configured so that the first magnetic field component H1 changes when their relative positions change in the Y direction. In this embodiment, when the first holding member 105 moves in the Y direction, the relative positions of the magnetic sensor 10 and the first magnet 21 change, and the first magnetic field component H1 changes.

[0097] The magnetic sensor 10 of this embodiment includes: a magnetic field conversion unit 11, which receives the magnetic field component (first magnetic field component H1) in the Z direction generated by the first magnet 21 as an input magnetic field, converts the first magnetic field component H1 into a magnetic field component (second magnetic field component H2) in the Y direction and outputs it; a magnetic field detection unit 12, which is provided at a position where the second magnetic field component H2 output as an output magnetic field from the magnetic field conversion unit 11 can be applied; and a magnetic shield 13, which is used to shield the magnetic field component in the Y direction included in the partial magnetic field generated by the first magnet 21 from being applied as an external magnetic field to the magnetic field detection unit 12 (see Figures 7 to 10 ).

[0098] The magnetic field conversion unit 11 includes a plurality of magnetic yokes 111 made of a soft magnetic material. In this embodiment, the magnetic field conversion unit 11 includes a plurality of magnetic yokes 111 as an example, but the present invention is not limited to this. The magnetic field conversion unit 11 may also include a single magnetic yoke 111. The plurality of magnetic yokes 111 are shaped such that the length in the X direction, which is the third direction, is longer than the length in the Y direction, for example, having a rectangular shape when viewed along the Z direction. The plurality of magnetic yokes 111 may be arranged so that the long side direction of each magnetic yoke 111 is parallel to the X direction when viewed along the Z direction, or may be arranged in parallel along the Y direction. In this embodiment, the shape, length in the long side direction, and length in the short side direction of the plurality of magnetic yokes 111 are the same as each other, but at least one of them may be different. In addition, each magnetic yoke 111 is continuous in the X direction, but may also be divided into multiple (for example, two) in the X direction. In addition, the rectangular shape of each magnetic yoke 111 when viewed along the Z direction is an example and is not limited to this embodiment. For example, the shape of each yoke 111 when viewed in the Z direction may be a quadrilateral with four corners of 89 to 91 degrees, or a rectangle with four rounded corners.

[0099] The magnetic field detecting unit 12 receives the first magnetic field component H1 as the input magnetic field, which is converted by the magnetic field converting unit 11 (yoke 111) and outputted as the second magnetic field component H2 (see Figures 15A to 15D ), and outputs a signal corresponding to the change of the first magnetic field component H1.

[0100] The magnetic field detection unit 12 includes a first magnetic field detection unit R1, a second magnetic field detection unit R2, a third magnetic field detection unit R3 and a fourth magnetic field detection unit R4. The first magnetic field detection unit R1, the second magnetic field detection unit R2, the third magnetic field detection unit R3 and the fourth magnetic field detection unit R4 respectively include first magnetoresistance units R11 to R41 and second magnetoresistance units R12 to R42. Each of the first magnetoresistance units R11 to R41 and the second magnetoresistance units R12 to R42 only needs to include at least one magnetoresistance effect element 120, but may also include an element array in which a plurality of magnetoresistance effect elements 120 are connected in series. Figures 8A to 8D In the example shown, each of the first magnetoresistance sections R11 to R41 and the second magnetoresistance sections R12 to R42 includes an element array formed by connecting eight magnetoresistance effect elements 120 in series. In this embodiment, the number of magnetoresistance effect elements 120 included in the first magnetoresistance sections R11 to R41 is not limited to the number of magnetoresistance effect elements 120 included in the second magnetoresistance sections R12 to R42 being the same (see Figures 8A to 8D). The number of magnetoresistance effect elements 120 included in the first magnetoresistance sections R11 to R41 and the number of magnetoresistance effect elements 120 included in the second magnetoresistance sections R12 to R42 may be different. In this case, the ratio (number ratio) of the number of magnetoresistance effect elements 120 included in the first magnetoresistance sections R11 to R41 and the number of magnetoresistance effect elements 120 included in the second magnetoresistance sections R12 to R42 may be, for example, 2:1 to 10:1 or 1:2 to 1:10, or 2:1 to 4:1 or 1:2 to 1:4. When the number of magnetoresistance effect elements 120 included in the first magnetoresistance sections R11 to R41 and the number of magnetoresistance effect elements 120 included in the second magnetoresistance sections R12 to R42 are the same, a stable output can be obtained from the magnetic sensor device regardless of whether the bias magnetic field Hb in the +Y direction or the bias magnetic field Hb in the -Y direction is applied to the magnetic sensor 10. On the other hand, when their numbers are different, there is a risk that the sensitivity of the magnetic sensor device will be reduced depending on the direction of the bias magnetic field Hb applied to the magnetic sensor 10. However, by setting the number ratio to the above range, by applying the bias magnetic field Hb in only one direction (for example, +Y direction or -Y direction) to the magnetic sensor 10, the sensitivity of the magnetic sensor device can be made better than when the number ratio is 1:1 (the same).

[0101] The magnetic field detection unit 12 may include a first magnetic resistance unit and a second magnetic resistance unit connected in series, or may include a first magnetic resistance unit and a second magnetic resistance unit connected in parallel. For example, each of the first magnetic field detection unit R1, the second magnetic field detection unit R2, the third magnetic field detection unit R3, and the fourth magnetic field detection unit R4 may include first magnetic resistance units R11 to R41 and second magnetic resistance units R12 to R42 connected in series (see Figure 8A 、 Figure 13A ), and may also include first magnetic resistance portions R11 to R41 and second magnetic resistance portions R12 to R42 connected in parallel (see Figure 8B 、 Figure 13B ).

[0102] In addition, the magnetic field detection unit 12 may also include a first magnetic resistance unit and a second magnetic resistance unit connected in series and a first magnetic resistance unit and a second magnetic resistance unit connected in parallel. Specifically, each of two magnetic field detection units among the first magnetic field detection unit R1, the second magnetic field detection unit R2, the third magnetic field detection unit R3 and the fourth magnetic field detection unit R4 may include a first magnetic resistance unit and a second magnetic resistance unit connected in series, and each of the other two magnetic field detection units may include a first magnetic resistance unit and a second magnetic resistance unit connected in parallel. For example, each of the first magnetic field detection unit R1 and the third magnetic field detection unit R3 may include a first magnetic resistance unit R11, R31 and a second magnetic resistance unit R12, R32 connected in series, and each of the second magnetic field detection unit R2 and the fourth magnetic field detection unit R4 may include a first magnetic resistance unit R21, R41 and a second magnetic resistance unit R22, R42 connected in parallel (refer to Figure 8C 、 Figure 13C ). In addition, the first magnetic field detection unit R1 and the second magnetic field detection unit R2 may each include first magnetic resistance units R11 and R21 and second magnetic resistance units R12 and R22 connected in parallel, and the third magnetic field detection unit R3 and the fourth magnetic field detection unit R4 may each include first magnetic resistance units R31 and R41 and second magnetic resistance units R32 and R42 connected in series (see Figure 8D 、 Figure 13D ). In addition, although not shown in the figure, the first magnetic field detection part R1 and the third magnetic field detection part R3 may each include a first magnetic resistance part R11, R31 and a second magnetic resistance part R12, R32 connected in parallel, and the second magnetic field detection part R2 and the fourth magnetic field detection part R4 may each include a first magnetic resistance part R21, R41 and a second magnetic resistance part R22, R42 connected in series. Alternatively, the first magnetic field detection part R1 and the second magnetic field detection part R2 may each include a first magnetic resistance part R11, R21 and a second magnetic resistance part R12, R22 connected in series, and the third magnetic field detection part R3 and the fourth magnetic field detection part R4 may each include a first magnetic resistance part R31, R41 and a second magnetic resistance part R32, R42 connected in parallel.

[0103] As the magnetoresistive effect element 120 of this embodiment, for example, an MR element such as a TMR element or a GMR element can be used. The magnetoresistive effect element 120 includes an MR stack 125 including an antiferromagnetic layer 124, a magnetization fixed layer 123, a nonmagnetic layer 122, and a free layer 121 stacked in this order (see Figure 11The antiferromagnetic layer 124 is made of an antiferromagnetic material and functions to fix the magnetization direction of the magnetization-fixed layer 123 by generating exchange coupling with the magnetization-fixed layer 123. Alternatively, the antiferromagnetic layer 124 can be omitted by providing the magnetization-fixed layer 123 with a laminated ferromagnetic structure of a ferromagnetic layer / non-magnetic intermediate layer / ferromagnetic layer, and by providing a so-called self-pinned layer (SFP layer) in which the two ferromagnetic layers are antiferromagnetically coupled.

[0104] The magnetization direction of the magnetization fixed layer 123 of the magnetoresistive effect element 120 is along the Y direction. The magnetization direction of the magnetization fixed layer 123 of the magnetoresistive effect element 120 included in the first magnetoresistive sections R11 to R41 and the magnetization direction of the magnetoresistive effect element 120 included in the second magnetoresistive sections R12 to R42 are antiparallel to each other. For example, the magnetization direction of the magnetization fixed layer 123 of the magnetoresistive effect element 120 included in the first magnetoresistive sections R11 to R41 can be along the +Y direction, while the magnetization direction of the magnetization fixed layer 123 of the magnetoresistive effect element 120 included in the second magnetoresistive sections R12 to R42 can be along the -Y direction.

[0105] In a TMR element, the nonmagnetic layer 122 serves as a tunnel barrier layer. In a GMR element, the nonmagnetic layer 122 serves as a nonmagnetic conductive layer. In both TMR and GMR elements, the resistance value varies depending on the angle between the magnetization direction of the free layer 121 and the magnetization direction of the fixed magnetization layer 123. The resistance value is minimum when the angle is 0° (the magnetization directions are parallel to each other), and maximum when the angle is 180° (the magnetization directions are antiparallel to each other).

[0106] The magnetoresistive effect element 120 may also be formed by connecting a plurality of MR stacks 125 having a substantially rectangular shape when viewed in the Z direction in series via upper lead electrodes 126 and lower lead electrodes 127 (see FIG. Figure 12 ). In addition, Figure 12While the MR stack 125 shown in the figure allows current to flow in the stacking directions (+Z and -Z directions), the magnetoresistive element 120 of this embodiment may also be a CIP (Current In Plane) type element, in which current flows in the in-plane direction (e.g., +X or -X directions) of the MR stack 125. The upper lead electrode 126 and the lower lead electrode 127 are formed from a single conductive material, or a composite film of two or more conductive materials, such as Cu, Al, Au, Ta, or Ti. Furthermore, the term "substantially rectangular" includes not only a rectangular shape in which the length in the X direction is longer than the length in the Y direction when viewed along the Z direction, but also a rectangular shape in which the length in the X direction is longer than the length in the Y direction and the four corners are 89 to 91 degrees, and a rectangular shape in which the length in the X direction is longer than the length in the Y direction and the four corners are rounded. In this embodiment, the shape of the MR stack 125 when viewed along the Z direction is not limited to a substantially rectangular shape; for example, an elliptical shape or an oblong shape may also be used. Even in this case, when viewed along the Z direction, the major axis of the elliptical shape, the oval shape, or the like is in the X direction, and the minor axis is in the Y direction.

[0107] The plurality of lower lead electrodes 127 have, for example, a generally rectangular shape. A predetermined gap is provided between adjacent lower lead electrodes 127 in the direction in which the plurality of MR stacks 125 are electrically connected in series, thereby connecting the plurality of MR stacks 125 in series. The adjacent MR stacks 125 are electrically connected to each other. An MR stack 125 is provided near each of the longitudinal ends of the lower lead electrodes 127. In other words, two MR stacks 125 are provided on each of the plurality of lower lead electrodes 127.

[0108] A plurality of upper lead electrodes 126 are provided on the plurality of MR stacks 125. Each upper lead electrode 126 has, for example, an elongated, substantially rectangular shape. The upper lead electrodes 126 are arranged to connect the plurality of MR stacks 125 in series, with a predetermined gap between adjacent upper lead electrodes 126 in the direction of electrical series connection of the plurality of MR stacks 125. This arrangement electrically connects adjacent MR stacks 125 to each other. Furthermore, a cover layer (protective layer) may be provided between the free layer 121 and the lower lead electrode 127 or the upper lead electrode 126.

[0109] When viewed along the Z direction, in each of the first magnetic field detection portion R1 and the fourth magnetic field detection portion R4, the plurality of magnetoresistance effect elements 120 included in the first magnetoresistance portions R11 and R41 are arranged on the +Y side of the magnetic field conversion portion 11 (magnetic yoke 111) closest to each magnetoresistance effect element 120 in the Y direction, and the plurality of magnetoresistance effect elements 120 included in the second magnetoresistance portions R12 and R42 are arranged on the -Y side of the magnetic field conversion portion 11 (magnetic yoke 111) closest to each magnetoresistance effect element 120 in the Y direction (see FIG. Figures 8A to 8D ). In addition, in each of the second magnetic field detection unit R2 and the third magnetic field detection unit R3, the plurality of magnetoresistance effect elements 120 included in the first magnetoresistance units R21 and R31 are arranged on the -Y side of the magnetic field conversion unit 11 (magnetic yoke 111) closest to each magnetoresistance effect element 120 in the Y direction, and the plurality of magnetoresistance effect elements 120 included in the second magnetoresistance units R22 and R32 are arranged on the +Y side of the magnetic field conversion unit 11 (magnetic yoke 111) closest to each magnetoresistance effect element 120 in the Y direction (see Figures 8A to 8D The plurality of magnetoresistive effect elements 120 are arranged at positions symmetrical to each other about an axis passing through the center of the short side of the magnetic field conversion unit 11 (yoke 111) (an axis extending along the long side of the magnetic field conversion unit 11 (yoke 111)) (see FIG. Figures 8A to 8D ). In addition, it is not limited to Figures 8A to 8D In the embodiment shown, the length (length in the Y direction) between the axis of at least one magnetic field conversion unit 11 (yoke 111) and the magnetoresistance effect element 120 located on the +Y side of the magnetic field conversion unit 11 (yoke 111) and the length (length in the Y direction) between the axis of the magnetic field conversion unit 11 (yoke 111) and the magnetoresistance effect element 120 located on the -Y side of the magnetic field conversion unit 11 (yoke 111) can be substantially the same as or different from each other. The two lengths being substantially the same means that the ratio of the two lengths is approximately 1:0.95 to 1:1.05. Furthermore, the multiple magnetoresistance effect elements 120 do not need to be arranged in positions that are linearly symmetrical about the axis of at least one magnetic field conversion unit 11 (yoke 111).

[0110] The magnetic shield 13 includes a first magnetic shield 131 and a second magnetic shield 132 positioned so as to sandwich the magnetic field converter 11 and the magnetic field detector 12 when viewed in the Z direction (see FIG. Figures 9 to 12). That is, the magnetic shield 13 overlaps with the magnetic field conversion unit 11 and the magnetic field detection unit 12 when viewed along the Z direction. In addition, as long as the effect of the magnetic sensor device of this embodiment is achieved, the magnetic shield 13 may overlap with a portion of the magnetic field conversion unit 11 and the magnetic field detection unit 12 when viewed along the Z direction, or may overlap with the entirety of the magnetic field conversion unit 11 and the magnetic field detection unit 12. When viewed along the Z direction, the first magnetic shield 131 is located closer to the +Z direction (above) than the magnetic field conversion unit 11 and the magnetic field detection unit 12, and the second magnetic shield 132 is located closer to the -Z direction (below) than the magnetic field conversion unit 11 and the magnetic field detection unit 12. The first magnetic shield 131 and the second magnetic shield 132 may each have a shape such that, when viewed along the Z direction, their maximum length in the Y direction is shorter than their maximum length in the X direction. For example, they may have a rectangular shape, a quadrilateral with four corners having angles of 89 to 91 degrees, a rectangular shape with rounded corners, a rectangular shape with four chamfered corners (octagonal shape), an oblong shape including an ellipse, a shape in which two opposing short sides of a rectangle are arc-shaped, a trapezoid, a parallelogram, a rhombus, or the like. Furthermore, when the magnetic shield 13 including the first magnetic shield 131 and the second magnetic shield 132 has a quadrilateral shape such as a quadrilateral with four corners having angles of 89 to 91 degrees, a trapezoid, a rhombus, or the like, at least one of the two sets of opposing sides may be parallel, or both sets of opposing sides may be non-parallel.

[0111] The magnetic shield 13 only needs to be made of, for example, a soft magnetic material. Examples of soft magnetic materials include NiFe. When the magnetic shield 13 is made of NiFe, the thermal stress of the magnetic shield 13 is reduced. Therefore, it is preferred that the magnetic shield 13 be made of NiFe having a Ni ratio of 35 to 60% by mass. If the NiFe has such a composition, the thermal expansion coefficient can be reduced. When the magnetic properties of the magnetic shield 13 are also considered, it is preferred that the magnetic shield 13 be made of NiFe having a Ni ratio of 40 to 60% by mass. As one of the performance requirements for the magnetic shield 13, a large maximum magnetic flux absorption amount can be cited. The maximum magnetic flux absorption amount of the magnetic shield 13 is substantially proportional to the product of the saturation magnetization and the thickness (dimension in the Z direction) of the magnetic shield 13. In order to ensure the performance of the magnetic shield 13, the product of the saturation magnetization and the thickness of the magnetic shield 13, that is, the magnetic moment per unit area, is preferably 0.6 emu / cm 2 above.

[0112] Furthermore, in this embodiment, the magnetic shield 13 includes a first magnetic shield 131 positioned above (on the +Z side) one side of the magnetic field converter 11 and magnetic field detector 12 when viewed in the Z direction, and a second magnetic shield 132 positioned below (on the -Z side) the other side of the magnetic field converter 11 and magnetic field detector 12. However, as long as the function of the magnetic shield 13 is achieved, either the first magnetic shield 131 or the second magnetic shield 132 may be omitted. Furthermore, at least one of the first magnetic shield 131 and the second magnetic shield 132 may be configured as multiple magnetic shields arranged in parallel in the Y direction. Arranging multiple magnetic shields in parallel in the Y direction can relatively increase the area available for the installation of the magnetic field converter 11 and magnetic field detector 12. Furthermore, when the spacing between magnetic shields arranged in parallel in the Y direction (the spacing in the Y direction) is relatively narrow, the magnetic shields tend to saturate easily. However, by relatively increasing this spacing, this tendency to saturate can be suppressed. Furthermore, at least one of the first magnetic shield 131 and the second magnetic shield 132 may be configured as multiple magnetic shields arranged in parallel in the X or Z direction.

[0113] The circuit configuration of the magnetic field detector 12 of this embodiment may be a Wheatstone bridge circuit C formed by bridging four magnetic field detectors (first to fourth magnetic field detectors R1 to R4) (see Figures 13A to 13D For example, the Wheatstone bridge circuit C constituting the magnetic field detector 12 may be formed by connecting in parallel a first bridge circuit C1 including the first magnetic field detector R1 and the second magnetic field detector R2 and a second bridge circuit C2 including the third magnetic field detector R3 and the fourth magnetic field detector R4.

[0114] The Wheatstone bridge circuit C constituting the magnetic field detector 12 includes a power supply port V, a ground port G, a first output port E1, a second output port E2, a first magnetic field detector R1 disposed between the power supply port V and the first output port E1, a second magnetic field detector R2 disposed between the first output port E1 and the ground port G, a third magnetic field detector R3 disposed between the power supply port V and the second output port E2, and a fourth magnetic field detector R4 disposed between the second output port E2 and the ground port G. A constant current source is connected to the power supply port V to apply a power supply voltage (constant current) of a predetermined magnitude, and the ground port G is connected to the ground. The constant current applied to the power supply port V is controlled to a predetermined current value by a driver IC (not shown).

[0115] In this embodiment, the magnetization directions ( Figures 14A to 16D The solid arrows shown in FIG. 2 are fixed in the same direction (+Y direction) (refer to FIG. Figures 14A to 16DOn the other hand, the magnetization direction ( Figures 14A to 16D The solid arrows shown in FIG. 2 are fixed in the same direction (-Y direction) (refer to FIG. Figures 14A to 16D ). Furthermore, the magnetization directions of the fixed magnetization layers 123 in all MR stacks 125 only need to be substantially fixed to each other along the Y direction. In this case, the magnetization directions of the fixed magnetization layers 123 in each MR stack 125 included in the first magnetoresistive sections R11 to R41 only need to be tilted at an angle of less than 10° relative to the +Y direction, and the magnetization directions of the fixed magnetization layers 123 in each MR stack 125 included in the second magnetoresistive sections R21 to R42 only need to be tilted at an angle of less than 10° relative to the -Y direction. When viewed along the Z direction, all MR stacks 125 have a shape that is elongated in the X direction (e.g., a roughly rectangular shape, an elliptical shape, an oblong shape, etc.). Therefore, the free layer 121 in each MR stack 125 has shape anisotropy with the easy magnetization axis oriented in the X direction. As a result, the magnetization directions ( Figures 14A to 14D The dashed arrows shown in FIG. 1 are the same as each other and are in the orthogonal direction (+X direction) relative to the magnetization direction of the magnetization pinned layer 123 (see FIG. Figures 14A to 14D Since the magnetization directions of the fixed magnetization layer 123 and the free layer 121 are in the above-described directions, as the resistance values of the first to fourth magnetic field detection units R1 to R4 change in response to the second magnetic field component H2, the potential difference between the first output port E1 and the second output port E2 changes, and a signal representing the change in the potential difference is output.

[0116] In the magnetic sensor device of this embodiment, when a first magnetic field component H1 parallel to the Z direction of a partial magnetic field as a portion of the magnetic field generated by the first magnet 21 is input to the magnetic field conversion unit 11, the magnetic field conversion unit 11 converts the component into a second magnetic field component H2 parallel to the Y direction and outputs the component. The second magnetic field component H2 in the +Y direction is applied to the magnetoresistance effect element 120 included in the first magnetoresistance sections R11 and R41 of the first magnetic field detection unit R1 and the fourth magnetic field detection unit R4, respectively, and the second magnetic field component H2 in the -Y direction is applied to the magnetoresistance effect element 120 included in the second magnetoresistance sections R12 and R42, respectively. The magnetization direction of each free layer 121 changes accordingly (see FIG. 1 ). Figures 15A to 15DOn the other hand, the second magnetic field component H2 in the -Y direction is applied to the magnetoresistance effect element 120 included in the first magnetoresistance portion R21 and R31 of the second magnetic field detection portion R2 and the third magnetic field detection portion R3, and the second magnetic field component H2 in the +Y direction is applied to the magnetoresistance effect element 120 included in the second magnetoresistance portion R22 and R32, respectively. The magnetization direction of each free layer 121 changes accordingly (see Figures 15A to 15D ). As a result, the angles θ11, θ12, θ41, and θ42 formed by the magnetization of the free layer 121 and the magnetization fixed layer 123 in the first magnetic resistance parts R11, R41 and the second magnetic resistance parts R12, R42 of the first magnetic field detection part R1 and the fourth magnetic field detection part R4 are less than 90° (refer to Figures 15A to 15D On the other hand, the angles θ21, θ22, θ31, and θ32 formed by the magnetization of the free layer 121 and the magnetization fixed layer 123 in the first magnetoresistive portions R21, R31 and the second magnetoresistive portions R22, R32 of the second magnetic field detection portion R2 and the third magnetic field detection portion R3 are greater than 90° (see Figures 15A to 15D ). In addition, Figures 15A to 15D In FIG. 1 , the dashed arrow indicates the magnetization of the free layer 121 whose direction is changed by application of the second magnetic field component H2 , and the hollow dashed arrow indicates the magnetization direction of the free layer 121 in the initial state.

[0117] As described above, the partial magnetic field, which is a portion of the magnetic field generated by the first magnet 21, includes a magnetic field component parallel to the Y direction. Most of this Y-direction magnetic field component is absorbed by the magnetic shield 13, but not all of this magnetic field component is completely absorbed by the magnetic shield 13. A portion of this magnetic field component is applied to the magnetoresistive element 120 as the bias magnetic field component Hb, thereby changing the magnetization direction of the free layer 121 (see Figures 16A to 16D ). In addition, Figures 16A to 16D In the figure, the dotted arrows represent the magnetization of the free layer 121 whose direction changes due to the application of the second magnetic field component H2 and the bias magnetic field component Hb, and the hollow dotted arrows represent the magnetization direction of the free layer 121 in the initial state. As a result, the angles θ11', θ21', θ31', θ41', θ12', θ22', θ32', and θ42' formed by the magnetization of the free layer 121 and the magnetization fixed layer 123 in the first magnetic resistance parts R11 to R41 and the second magnetic resistance parts R12 to R42 of the first to fourth magnetic field detection parts R1 to R4 are respectively Figures 16A to 16D ) than the angles θ11, θ21, θ31, θ41, θ12, θ22, θ32, and θ42 that should be displayed when the bias magnetic field component Hb is not applied (refer to Figures 15A to 15D As a result, the outputs of the first output port E1 and the second output port E2 vary.

[0118] However, in this embodiment, the magnetization of the fixed magnetization layers 123 of all magnetoresistive elements 120 included in the first to fourth magnetic field detection units R1 to R4 is fixed in the Y direction, and the initial magnetization of the free layers 121 of all magnetoresistive elements 120 is in the same direction. Therefore, when the bias magnetic field component Hb is applied to the magnetoresistive elements 120, the fluctuation in the output of the first output port E1 and the fluctuation in the output of the second output port E2 are substantially the same. If the fluctuation in the output of the first output port E1 and the fluctuation in the output of the second output port E2 due to the bias magnetic field component Hb differ, the output of the magnetic sensor device may be offset. However, in this embodiment, this offset can be suppressed. Furthermore, in this embodiment, the initial magnetization direction of the free layer 121 is orthogonal to the bias magnetic field component Hb, thereby suppressing a decrease in the sensitivity of the magnetic sensor device. In addition, in this embodiment, each of the first to fourth magnetic field detection units R1 to R4 includes: a first magnetoresistance unit R11 to R41, which includes a magnetoresistance effect element 120 having a magnetization fixed layer 123 fixedly magnetized in the +Y direction; and a second magnetoresistance unit R12 to R42, which includes a magnetoresistance effect element 120 having a magnetization fixed layer 123 fixedly magnetized in the -Y direction. As a result, the resistance fluctuation in the first magnetoresistance units R11 to R41 and the resistance fluctuation in the second magnetoresistance units R12 to R42 caused by the bias magnetic field Hb can be offset, thereby suppressing the fluctuation of the midpoint potential of the magnetic sensor device. In particular, when a constant current is applied to the power supply port V, when the first magnetoresistance units R11 to R41 and the second magnetoresistance units R12 to R42 included in each of the first to fourth magnetic field detection units R1 to R4 are connected in parallel (refer to Figure 8B 、 Figure 13B ), the effect of suppressing fluctuations in the midpoint potential of the magnetic sensor device is significantly excellent. Furthermore, in this embodiment, the midpoint potential refers to the potential above ground G at the output of the first output port E1 and the output of the second output port E2 of the Wheatstone bridge circuit C constituting the magnetic sensor 10 when the magnetic field to be detected by the magnetic sensor 10 (the second magnetic field H2) is zero.

[0119] When viewed along the Z direction, in a magnetoresistive element 120 having a shape with the X direction as the longitudinal direction, the magnetization direction of the magnetization fixed layer 123 is fixed in the Y direction. When a bias magnetic field Hb in the Y direction is applied to the magnetoresistive element 120, the magnetization direction of the free layer 121 changes. In this case, the resistance R of the magnetoresistive element 120 is 120 (Ω) is represented by the following formula (1).

[0120] [Formula 1]

[0121]

[0122] In the above formula (1), G 120 represents the conductance (Ω) of the magnetoresistive element 120. -1 )”, △G 120 represents the amplitude of change in conductance of the magnetoresistive element 120 (Ω -1 )”, δθ represents “the angular displacement amount (deg) of the magnetization of the free layer 121”.

[0123] As can be seen from equation (1), the magnetization direction of the free layer 121 fluctuates due to the influence of the Y-direction bias magnetic field Hb, causing the resistance of the magnetoresistive element 120 to change due to the application of the second magnetic field component H2. In other words, the output from the magnetic sensor device deviates from the ideal sine wave. In other words, the Y-direction bias magnetic field Hb causes a fluctuation in the midpoint potential.

[0124] like Figure 8A and Figure 13A As shown, when the first magnetoresistance parts R11 to R41 and the second magnetoresistance parts R12 to R42 of the first to fourth magnetic field detection parts R1 to R4 are connected in series, the resistance R of each of the first to fourth magnetic field detection parts R1 to R4 is expressed by the following formula (2) based on the resistance R1 (Ω) of the magnetoresistance effect element 120 included in the first magnetoresistance part R11 to R41 and the resistance R2 (Ω) of the magnetoresistance effect element 120 included in the second magnetoresistance part R12 to R42.

[0125] R=R1+R2……(2)

[0126] Since the magnetization directions of the magnetization fixed layers 123 of the magnetoresistive effect elements 120 included in the first magnetoresistive sections R11 to R41 and the magnetization fixed layers 123 of the magnetoresistive effect elements 120 included in the second magnetoresistive sections R12 to R42 are antiparallel to each other, the first to fourth magnetic field detection sections R1 to R4 can, as a whole, offset the influence of the change in the magnetization direction of the free layer caused by the bias magnetic field Hb in the Y direction on the output from the magnetic sensor device, thereby suppressing the change in the midpoint potential. However, as can be seen from the above formula (2), the bias magnetic field Hb in the Y direction may cause extremely small changes in the midpoint potential.

[0127] On the other hand, Figure 8B and Figure 13B As shown, when the first magnetoresistance parts R11 to R41 and the second magnetoresistance parts R12 to R42 of the first to fourth magnetic field detection parts R1 to R4 are connected in parallel, the resistance R of each of the first to fourth magnetic field detection parts R1 to R4 is expressed by the following formula (3) based on the resistance R1 (Ω) of the magnetoresistance effect element 120 included in the first magnetoresistance part R11 to R41 and the resistance R2 (Ω) of the magnetoresistance effect element 120 included in the second magnetoresistance part R12 to R42.

[0128] R=(1 / R1+1 / R2) -1 ……(3)

[0129] Since the magnetization directions of the magnetization fixed layer 123 of the magnetoresistive effect element 120 included in the first magnetoresistive section R11 to R41 and the magnetization fixed layer 123 of the magnetoresistive effect element 120 included in the second magnetoresistive section R12 to R42 are antiparallel to each other, the first to fourth magnetic field detection sections R1 to R4 can, as a whole, offset the influence of the change in the magnetization direction of the free layer caused by the bias magnetic field Hb in the Y direction on the output from the magnetic sensor device. As can be seen from the above formula (3), theoretically, the change in the midpoint potential caused by the bias magnetic field Hb in the Y direction cannot be completely suppressed.

[0130] The embodiments described above are for easy understanding of the present invention and are not intended to limit the present invention. Therefore, the main contents of the various elements disclosed in the above embodiments also include all design changes and equivalents within the technical scope of the present invention.

[0131] In the above embodiment, a lens module is described as an example of an application in which a magnetic sensor device is provided, but the present invention is not limited to this embodiment. The magnetic sensor device of this embodiment can be used to detect position changes within the XY plane and position changes in the Z direction based on changes in the magnetic field in the Z direction. Examples of applications in which this magnetic sensor device is provided include actuators used in robot joint mechanisms, laptop computer opening and closing detection mechanisms, joysticks, brushless motors, magnetic encoders, and other electronic devices.

[0132] Example

[0133] Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the present invention is not limited to the following Examples and the like.

[0134] [Test Example 1]

[0135] Use with Figure 8A 、 Figure 9 、 Figure 10 and Figure 13A The magnetic sensor 10 (Sample 1) of the structure shown in FIG. 1 was subjected to a bias magnetic field Hb of 10 mT. The output (V OUT , V1) and the output of the second output port E2 (V OUT , V2), and differential output (dV OUTSimilarly, the output of the first output port E1 (V OUT , V1') and the output of the second output port E2 (V OUT , V2') and differential output (dV OUT , V1'-V2'). Put the result in Figure 17A and Figure 17B In addition, the anisotropic magnetic field of the free layer 121 of each magnetoresistive effect element 120 included in the first to fourth magnetic field detection units R1 to R4 is set to 25 mT.

[0136] [Test Example 2]

[0137] In addition to using Figure 8B 、 Figure 9 、 Figure 10 and Figure 13B The same test as in Experimental Example 1 was performed except for the magnetic sensor 10 (Sample 2) having the structure shown in FIG. 1 , and the output (V OUT , V1), the output of the second output port E2 (V OUT , V2) and differential output (dV OUT , V1-V2), and the output of the first output port E1 (V OUT , V1'), the output of the second output port E2 (V OUT , V2') and differential output (dV OUT , V1'-V2'). Put the result in Figure 18A and Figure 18B Indicated in.

[0138] [Test Example 3]

[0139] In addition to using Figure 8C 、 Figure 9 、 Figure 10 and Figure 13C The same test as in Experimental Example 1 was performed except for the magnetic sensor 10 (Sample 3) having the structure shown in FIG. 1 , and the output (V OUT , V1), the output of the second output port E2 (V OUT , V2) and differential output (dV OUT , V1-V2), and the output of the first output port E1 (V OUT , V1'), the output of the second output port E2 (V OUT , V2') and differential output (dV OUT , V1'-V2'). The result is Figure 19A and Figure 19B Indicated in.

[0140] [Test Example 4]

[0141] In addition to using Figure 8D 、 Figure 9 、 Figure 10 and Figure 13D The same test as in Experimental Example 1 was performed except for the magnetic sensor 10 (Sample 4) having the structure shown in FIG. 1 , and the output (V OUT , V1), the output of the second output port E2 (V OUT , V2) and differential output (dV OUT , V1-V2), and the output of the first output port E1 (V OUT , V1'), the output of the second output port E2 (V OUT , V2') and differential output (dV OUT , V1'-V2'). Put the result in Figure 20A and Figure 20B Indicated in.

[0142] Figure 17A 、 Figure 18A 、 Figure 19A and Figure 20A The vertical axis of the graph shows the differential output (dV OUT ), and Figure 17B 、 Figure 18B 、 Figure 19B and Figure 20B The vertical axis of the graph shown is output (V OUT ) values are all standardized values.

[0143] according to Figure 17A 、 Figure 18A 、 Figure 19A and Figure 20A The results shown confirm that, in the magnetic sensors 10 of Samples 1 to 4, even when the bias magnetic field Hb is applied, the sensitivity hardly fluctuates and an offset hardly occurs.

[0144] In addition, according to Figure 17B 、 Figure 18B 、 Figure 19B and Figure 20BThe results shown indicate that, for the magnetic sensors 10 of Samples 1 to 4, the midpoint potential fluctuation (mV) when the bias magnetic field Hb was applied was less than 2% of the midpoint potential (mV) when the bias magnetic field Hb was not applied, indicating that the midpoint potential was less likely to fluctuate. In particular, the magnetic sensor 10 (Sample 2) in which the first magnetoresistors R11 to R41 and the second magnetoresistors R12 to R42 were connected in parallel in all of the first to fourth magnetic field detectors R1 to R4, and the magnetic sensor 10 (Sample 3) in which the first magnetoresistors R21 and R41 and the second magnetoresistors R22 and R42 were connected in parallel in the second magnetic field detector R2 and the fourth magnetic field detector R4, demonstrated extremely excellent suppression of midpoint potential fluctuation.

[0145] [Test Example 5]

[0146] In the above-mentioned samples 1 and 2, the ratio (number ratio NR) of the number of magnetoresistance effect elements 120 included in the first magnetoresistance sections R11 to R41 of the first to fourth magnetic field detection sections R1 to R4 and the number of magnetoresistance effect elements 120 included in the second magnetoresistance sections R12 to R42 is set to 1:1, 2:1, 4:1, and 10:1, and the range of the magnetic field strength of the bias magnetic field Hb is set to -10mT to 10mT. The same as in Experiment 1 is performed, and the output (V1) of the first output port E1, the output (V2) of the second output port E2, and the differential output (V1-V2) are obtained by simulation, and the sensitivity (S) of the magnetic sensor device is obtained. The results are shown in Figure 21A and Figure 21B In addition, Figure 21A and Figure 21B In FIG. 5 , the sensitivity (S) value of the magnetic sensor device is a value normalized by setting the sensitivity when the magnetic field intensity of the bias magnetic field Hb is 0 mT to “1”.

[0147] like Figure 21A and Figure 21BAs shown, in Sample 1, it was confirmed that by varying the number of magnetoresistance effect elements 120 included in the first magnetoresistance sections R11 to R41 and the number of magnetoresistance effect elements 120 included in the second magnetoresistance sections R12 to R42, the bias magnetic field Hb applied to the magnetic sensor 10 is always in a single direction (e.g., the +Y direction), thereby further suppressing fluctuations in the sensitivity of the magnetic sensor device. Therefore, by incorporating the magnetic sensor device so that the bias magnetic field Hb is always applied in a single direction, a magnetic sensor device can be provided that is significantly more effective in suppressing sensitivity fluctuations due to the bias magnetic field Hb. On the other hand, when the number of magnetoresistance effect elements 120 included in the first magnetoresistance sections R11 to R41 and the number of magnetoresistance effect elements 120 included in the second magnetoresistance sections R12 to R42 are the same, the trajectory of sensitivity fluctuations remains unchanged regardless of whether the bias magnetic field Hb applied to the magnetic sensor 10 is in a single direction (e.g., the +Y direction) or in a different direction (e.g., the -Y direction). Therefore, in electronic equipment, etc., a bias magnetic field Hb in two directions (for example, +Y direction and -Y direction) may be applied to the magnetic sensor 10 depending on the position where the magnetic sensor device is installed. Even in this case, the sensitivity of the magnetic sensor device can be stabilized.

[0148] Explanation of symbols

[0149] 10 ...magnetic sensor; 11 ...magnetic field conversion unit; 111 ...magnetic yoke; 12 ...magnetic field detection unit; 120 ...magnetoresistive effect element; 13 ...magnetic shield; 131 ...first magnetic shield; 132 ...second magnetic shield.

Claims

1. A magnetic sensor, characterized in that: have: a magnetic field converter that receives an input magnetic field input along a first direction and outputs an output magnetic field along a second direction orthogonal to the first direction; a magnetic field detection unit provided at a position where the output magnetic field can be applied; as well as a magnetic shield that shields an external magnetic field along the second direction, When viewed along the first direction, the magnetic field conversion portion has a shape in which a length in a third direction perpendicular to both the first direction and the second direction is longer than a length in the second direction. When viewed along the first direction, the magnetic shield is provided at a position overlapping with the magnetic field conversion unit and the magnetic field detection unit. The magnetic field detection unit is composed of a Wheatstone bridge circuit in which a first bridge circuit including a first magnetic field detection unit and a second magnetic field detection unit is connected in parallel with a second bridge circuit including a third magnetic field detection unit and a fourth magnetic field detection unit. The first to fourth magnetic field detection units respectively include a first magnetic resistance unit and a second magnetic resistance unit. The first magnetoresistive section and the second magnetoresistive section included in each of the first to fourth magnetic field detection sections include magnetoresistive effect elements including magnetization fixed layers having magnetization directions different from each other. The magnetization direction of the magnetization fixed layer of the magnetoresistive element included in the first magnetoresistive portion and the magnetization direction of the magnetization fixed layer of the magnetoresistive element included in the second magnetoresistive portion are antiparallel to each other and are along the second direction.

2. The magnetic sensor according to claim 1, wherein The first magnetic resistance portion and the second magnetic resistance portion included in each of the first to fourth magnetic field detection units are connected in parallel.

3. The magnetic sensor according to claim 1, wherein The first magnetic resistance portion and the second magnetic resistance portion included in each of the first to fourth magnetic field detection units are connected in series.

4. The magnetic sensor according to claim 1, wherein The Wheatstone bridge circuit includes a power port, a ground port, a first output port and a second output port. The first magnetic field detection unit is provided between the power port and the first output port. The second magnetic field detection unit is provided between the first output port and the ground port, The third magnetic field detection unit is provided between the power port and the second output port. The fourth magnetic field detection unit is provided between the second output port and the ground port, The first magnetic resistance part and the second magnetic resistance part included in two of the first magnetic field detection part, the second magnetic field detection part, the third magnetic field detection part and the fourth magnetic field detection part are connected in parallel, and the first magnetic resistance part and the second magnetic resistance part included in the other two magnetic field detection parts are connected in series.

5. The magnetic sensor according to any one of claims 1 to 4, characterized in that The first magnetoresistive section and the second magnetoresistive section included in each of the first to fourth magnetic field detection sections each include a plurality of the magnetoresistive effect elements. The number of the magnetoresistance effect elements included in the first magnetoresistance portion is the same as the number of the magnetoresistance effect elements included in the second magnetoresistance portion.

6. The magnetic sensor according to any one of claims 1 to 4, characterized in that The first magnetoresistive section and the second magnetoresistive section included in each of the first to fourth magnetic field detection sections each include a plurality of the magnetoresistive effect elements. The number of the magnetoresistance effect elements included in the first magnetoresistance portion is greater than the number of the magnetoresistance effect elements included in the second magnetoresistance portion.

7. The magnetic sensor according to claim 6, wherein A ratio of the number of the magnetoresistance effect elements included in the first magnetoresistance portion to the number of the magnetoresistance effect elements included in the second magnetoresistance portion is 2:1 to 4:

1.

8. The magnetic sensor according to any one of claims 1 to 4, characterized in that The magnetic shield has a shape in which, when viewed along the first direction, a maximum length in the third direction is longer than a maximum length in the second direction.

9. The magnetic sensor according to any one of claims 1 to 4, characterized in that The plurality of magnetic field conversion units are arranged in parallel along the second direction.

10. The magnetic sensor according to any one of claims 1 to 4, characterized in that The magnetic shield includes a first magnetic shield and a second magnetic shield, The magnetic field conversion unit and the magnetic field detection unit are provided between the first magnetic shield and the second magnetic shield in the first direction.

11. The magnetic sensor according to any one of claims 1 to 4, characterized in that The magnetic shield is located on one side or the other side of the magnetic field conversion unit and the magnetic field detection unit along the first direction.

12. The magnetic sensor according to claim 1, wherein When viewed along the first direction, the first magnetic resistance portion and the second magnetic resistance portion included in each of the first to fourth magnetic field detection portions are arranged at line-symmetrical positions around an axis along the long side direction of the magnetic field conversion portion, and the axis passes through the center of the short side direction of the magnetic field conversion portion.

13. The magnetic sensor according to any one of claims 1 to 4, characterized in that The magnetoresistive effect element is a TMR element or a GMR element.

14. A position detection device, characterized in that: have: The magnetic sensor according to any one of claims 1 to 4; a magnetic field generating unit that generates the input magnetic field; and a substrate provided with the magnetic sensor, The magnetic field generating unit is supported by the substrate so as to be movable relative to the substrate in at least one of the second direction and the third direction.

15. An electronic device, characterized in that: A position detection device according to claim 14 is provided.

Images