JP5066576B2 - Magnetic detector - Google Patents

Description

  The present invention relates to a magnetic detection device capable of expanding a detection range of a magnet located on an XY plane as compared with the conventional case.

  For example, a magneto-resistance effect element (GMR element) is provided in a magnetic detection device for detecting an external magnetic field generated from a magnet.

  The magnetoresistive effect element 1 is a giant magnetoresistive effect element (GMR element) having a laminated structure of a pinned magnetic layer, a free magnetic layer, and a nonmagnetic layer interposed between the pinned magnetic layer and the free magnetic layer. For example, the magnetization direction of the fixed magnetic layer is fixed in the + X direction.

  FIG. 14 is a plan view showing a state where the magnet 2 is opposed to the magnetoresistive element 1. The upper and lower surfaces of the magnet 2 are magnetized surfaces, and as shown in FIGS. 15 to 17, for example, the upper surface 2a of the magnet 2 is magnetized to the S pole and the lower surface 2b is magnetized to the N pole.

  This magnetic detection device is compatible with bipolar detection. For example, as shown in FIG. 15, when the magnet 2 is positioned in the + X direction with respect to the magnetoresistive element 1, the magnetoresistive element 1 has a direction opposite to the magnetization direction (PIN direction) of the pinned magnetic layer. A horizontal magnetic field component H1 in the (−X direction) enters.

The free magnetic layer constituting the magnetoresistive effect element 1 faces the direction of the horizontal magnetic field component, and the electric resistance value of the magnetoresistive effect element 1 varies depending on the magnetization direction (PIN direction) of the pinned magnetic layer. At this time, when a horizontal magnetic field component H1 in a direction substantially opposite to the magnetization direction (PIN direction) of the pinned magnetic layer enters, the electrical resistance value of the magnetoresistive effect element 1 increases. As a result, the potential of the sensor circuit in which the magnetoresistive effect element 1 is incorporated fluctuates greatly from the midpoint potential, and an ON signal indicating that an external magnetic field from the magnet 2 is acting is output. ing. Although not shown, when the magnet 2 is positioned in the −X direction with respect to the magnetoresistive effect element 1, the magnetoresistive effect element 1 has the same direction (+ X direction) as the magnetization direction (PIN direction) of the pinned magnetic layer. A horizontal magnetic field component enters. As a result, the electrical resistance value of the magnetoresistive effect element 1 is reduced, and the potential of the sensor circuit in which the magnetoresistive effect element 1 is incorporated is greatly varied from the midpoint potential, and an ON signal is output. .
JP 2000-252545 A JP 2003-130933 A

  In the conventional bipolar magnetic detection device, the detection range of the magnet 2 located on the XY plane is limited to the area A shown in FIG.

  As shown in FIG. 16, when the magnet 2 was positioned in the + Y direction or the −Y direction with respect to the magnetoresistive element 1, the magnet 2 could not be detected.

  As shown in FIG. 16, when the magnet 2 is positioned in the + Y direction with respect to the magnetoresistive effect element 1, a horizontal magnetic field component H <b> 2 in the −Y direction enters the magnetoresistive effect element 1. However, since the magnetization direction (PIN direction) of the pinned magnetic layer is the + X direction, the magnetization direction of the pinned magnetic layer and the magnetization direction of the free magnetic layer are substantially orthogonal, and the electric resistance value of the magnetoresistive effect element 1 is intermediate. Value. As a result, the potential of the electric circuit incorporating the magnetoresistive effect element 1 does not vary from the midpoint potential, or even if the potential varies, the variation from the midpoint potential is small, and the external magnetic field from the magnet 2 is reduced. An off signal indicating that it is not acting is generated, and therefore it is impossible to detect the magnet 2 when the magnetoresistive element 1 is positioned in the + Y direction or the −Y direction.

  When the magnet 2 is positioned directly above the magnetoresistive effect element 1, as shown in FIG. 17, a perpendicular magnetic field component H3 acts on the magnetoresistive effect element 1 from the magnet 2, but in the first place. Since a horizontal magnetic field component for changing the electric resistance value of the magnetoresistive effect element 1 does not act, a blind spot region is formed even when the magnet 2 is positioned directly above (and directly below) the magnetoresistive effect element 1.

  Patent Document 1 discloses an invention related to “Hall Sensor”, and Patent Document 2 discloses an invention related to “Magnetic Sensor Element”. However, the above-described problems of the prior art are not described at all. The solution is not disclosed.

  Accordingly, the present invention is to solve the above-described conventional problems, and in particular, to provide a magnetic detection device capable of expanding the detection range of a magnet located on the XY plane as compared with the conventional one. It is aimed.

The magnetic detection device according to the present invention includes a magnetoresistive effect element whose lower surface and upper surface are arranged at different height positions with respect to the magnet of the magnetized surface, and whose electric resistance value fluctuates by receiving an external magnetic field from the magnet,
The magnetoresistive effect element has a structure in which at least a pinned magnetic layer, a free magnetic layer, and a nonmagnetic layer interposed between the pinned magnetic layer and the free magnetic layer are stacked in the height direction (Z direction). ,
The magnetization direction of the fixed magnetic layer is fixed in one direction of the X direction orthogonal to the Z direction, and the first magnetic body and the second magnetic material are spaced apart from each other in the X direction of the magnetoresistive element. And a magnetic body,
The opposing surfaces of the first magnetic body and the second magnetic body facing the X direction are arranged so as to be shifted from each other in the Y direction perpendicular to the X direction and the Z direction.

  Thereby, when the magnet is positioned in the Y direction with respect to the magnetoresistive effect element, the direction of the horizontal magnetic field component entering the magnetoresistive effect element is changed to a direction inclined from the conventional Y direction to the X direction, A magnet located in the Y direction with respect to the magnetoresistive element can be detected.

  Further, when the magnet 2 is positioned in the X direction with respect to the magnetoresistive effect element, the magnetic flux density of the horizontal magnetic field component can be amplified, and the detection range in the X direction can be expanded as compared with the conventional case. By the above, compared with the past, the detection range of the magnet located on an XY plane can be expanded.

  In the present invention, the first magnetic body and the second magnetic body may include an X-direction extending portion extending in a direction substantially parallel to the X direction from the opposing surface and away from the magnetoresistive element. It is preferable that a Y-direction extension portion extending in a direction substantially parallel to the Y direction from the opposite surface side of the X-direction extension portion to the Y-direction and extending away from each other. By providing the X-direction extension portion, a horizontal magnetic field component inclined in the X direction from the Y direction can be made to enter the magnetoresistive element more appropriately, and by providing the Y-direction extension portion, the magnet As a result, it is possible to enhance the magnetic flux collection effect of the external magnetic field generated from the magnetic field, and to effectively widen the detection range of the magnet located on the XY plane as compared with the conventional case.

  In the present invention, it is preferable that the opposing surfaces of the first magnetic body and the second magnetic body are shifted in the Z direction. As a result, even if the magnet is positioned directly above or below the magnetoresistive element, a horizontal magnetic field component approaching the same direction as or opposite to the magnetization direction of the pinned magnetic layer can enter the magnetoresistive element. In addition, it is possible to detect a magnet located directly above or below the magnetoresistive element.

Alternatively, the magnetic detection device according to the present invention includes a magnetoresistive element in which the lower surface and the upper surface are arranged at different height positions with respect to the magnetized surface magnet, and the electric resistance value fluctuates by receiving an external magnetic field from the magnet,
The magnetoresistive effect element has a structure in which at least a pinned magnetic layer, a free magnetic layer, and a nonmagnetic layer interposed between the pinned magnetic layer and the free magnetic layer are stacked in the height direction (Z direction). ,
The magnetization direction of the pinned magnetic layer is fixed in one direction of the X direction, and the first magnetic body and the second magnetic body are spaced apart on both sides of the magnetoresistive element in the X direction. Provided,
The opposing surfaces of the first magnetic body and the second magnetic body facing in the X direction are arranged so as to be shifted from each other in the Z direction.

  As a result, even if the magnet is located directly above or below the magnetoresistive effect element, the magnetoresistive effect element enters the same direction as or opposite to the magnetization direction of the pinned magnetic layer, or a horizontal magnetic field component approaching them. Therefore, it is possible to detect a magnet located directly above or below the magnetoresistive element, and the detection range of the magnet located on the XY plane can be expanded as compared with the conventional case.

  In the present invention, the first magnetic body and the second magnetic body may extend in a direction parallel to the X direction and extend away from the magnetoresistive effect element and be offset in the Z direction. A Z-direction extension portion extending from each X-direction extension portion in a direction substantially parallel to the Z-direction and approaching the magnetoresistive effect element, and extending from the X-direction extension portion. It is preferable that one surface facing the direction is the facing surface.

  As a result, even when the magnet is positioned directly above or below the magnetoresistive element, the magnet can be detected more effectively.

  According to the magnetic detection device of the present invention, it is possible to widen the detection range of the magnet located on the XY plane as compared with the conventional case.

  1 is a perspective view of a magnetic detection device according to the present embodiment, FIG. 2 is a side view of the magnetic detection device viewed from the direction of the arrow in FIG. 1, and FIG. 3 is a plan view for explaining a magnet detection range according to the present embodiment. FIG. 4 is a plan view when the magnet is positioned in the + X direction with respect to the magnetoresistive effect element. FIG. 5 is a plan view when the magnet is positioned in the −X direction with respect to the magnetoresistive effect element. 6 is a plan view when the magnet is positioned in the + Y direction with respect to the magnetoresistive effect element, FIG. 7 is a plan view when the magnet is positioned in the −Y direction with respect to the magnetoresistive effect element, and FIG. FIG. 9 is a cross-sectional view showing a laminated structure of the magnetoresistive effect element in the present embodiment, and FIG. 10 is a circuit configuration diagram of the magnetic detection device in the present embodiment. .

  Each direction of the X direction, the Y direction, and the Z direction is orthogonal to the remaining two directions. In each figure, the X direction is represented by + X direction and −X direction which are antiparallel to each other, and the Y direction is represented by + Y direction and −Y direction which are antiparallel to each other. In the following, the term “X direction” is used in a sense that includes both the + X direction and the −X direction, or does not specify the + X direction and the −X direction. The same applies to the “Y direction”.

  As shown in FIGS. 1 and 2, the magnetic detection device 10 of this embodiment includes a substrate 11, a magnetic sensor 12 installed on the substrate 11, a first magnetic body 13, and a second magnetic body 14. And is configured.

  The magnetic sensor 12 has a structure in which a magnetoresistive effect element, a fixed resistance element, an integrated circuit, and the like are incorporated and packaged.

  The first magnetic body 13 is provided on the substrate 11 via a base 15 at a position away from the magnetic sensor 12 in the + X direction, and the second magnetic body 14 is disposed with respect to the magnetic sensor 12. The through hole 11a formed in the substrate 11 is inserted from the back side at a position separated in the -X direction.

  The first magnetic body 13 and the second magnetic body 14 are preferably formed of a soft magnetic material such as NiFe.

  As shown in FIGS. 1 and 2, the first magnetic body 13 and the second magnetic body 14 are each provided with Z-direction extending portions 13a and 14a extending in a direction substantially parallel to the Z-direction, One surface in the X direction facing inward through the magnetic sensor 12 of the Z-direction extending portions 13a and 14a is a facing surface 13a1 and 14a1, respectively. Here, “substantially parallel to the Z direction” means to include an inclination range of up to 10 ° with respect to the Z direction.

  As shown in FIG. 1 and FIG. 2, the X-direction extending portions 13 b in a direction substantially parallel to the X direction and away from the magnetic sensor 12 from the opposite side of the facing surfaces 13 a 1 and 14 a 1 of the Z-direction extending portions 13 a and 14 a. 14b is provided. Here, “substantially parallel to the X direction” means to include an inclination range of up to 25 ° with respect to the X direction.

  As shown in FIG. 2, the X-direction extension 13b of the first magnetic body 13 is at a higher position in the height direction (Z direction) than the X-direction extension 14b of the second magnetic body 14, The Z-direction extension 13a of the first magnetic body 13 is bent downward from the X-direction extension 13b. On the other hand, the Z-direction extension 14a of the second magnetic body 14 is bent upward from the X-direction extension 14b.

  As shown in FIG. 1, the first magnetic body 13 and the second magnetic body 14 are substantially parallel to the Y direction from the opposite surface side of the facing surfaces 13a1 and 14a1 of the X direction extending portions 13b and 14b. Y-direction extending portions 13c and 14c extending in directions away from each other are provided. Here, “substantially parallel to the Y direction” means including an inclination range of up to 10 ° with respect to the Y direction.

  As shown in FIG. 9, the magnetoresistive effect element 20 incorporated in the magnetic sensor 12 includes a base layer 60, an antiferromagnetic layer 61, a fixed magnetic layer 62, a nonmagnetic material layer 63, a free magnetic layer 64, and The protective layers 65 are laminated in this order. The underlayer 60 is, for example, Ta, the antiferromagnetic layer 61 is, for example, IrMn, the pinned magnetic layer 62 is, for example, CoFe, the nonmagnetic material layer 63 is, for example, Cu, magnesium oxide, or aluminum oxide, and the free magnetic layer 64 is, for example, NiFe, a protective layer 65 is made of Ta, for example. For example, the stacking structure shown in FIG. 9 can be changed by reversing the stacking order or forming the pinned magnetic layer 62 with a stacked ferrimagnetic structure, but at least the pinned magnetic layer 62, the nonmagnetic material layer 63, and the free magnetic layer. Must have 64 three-layer structure.

  An exchange coupling magnetic field (Hex) is generated between the antiferromagnetic layer 61 and the pinned magnetic layer 62, and the magnetization direction (PIN direction) of the pinned magnetic layer 62 is pinned in one direction. In this embodiment, the magnetization direction (PIN direction) of the pinned magnetic layer 62 is the + X direction.

  On the other hand, the magnetization direction of the free magnetic layer 64 is not fixed and is directed to the direction of the acting horizontal magnetic field component.

  A characteristic part of the magnetic detection device 10 of the present embodiment is that the first magnetic body is provided with predetermined intervals T1 and T2 (for example, 0.1 to 0.3) on both sides in the X direction of the magnetoresistive effect element 20. 13 and the second magnetic body 14 are provided, and the opposing surfaces 13a1 and 14a1 facing the X direction of the first magnetic body 13 and the second magnetic body 14 are arranged so as to be shifted from each other in the Y direction and the Z direction. (See FIGS. 2 and 4).

  Thereby, the detection range of the magnet 30 located on the XY plane can be expanded to the area B shown in FIG.

  For example, the upper surface 30a of the magnet 30 is magnetized to the S pole and the lower surface 30b is magnetized to the N pole (see FIG. 8). The magnet has a width dimension T4 and a length dimension T5 of 10 to 30 mm, and a thickness dimension T6 of 10 to 20 mm (see FIGS. 3 and 8).

  The magnet 30 is located above the magnetoresistive effect element 20, and when the magnet 30 is located directly above the magnetoresistive effect element 20 as shown in FIG. The height dimension is T3. The height dimension T3 between the magnet 30 and the magnetoresistive effect element 20 shown in FIG. 8 is in the range of 30 to 50 mm.

  Consider the case where the magnet 30 shown in FIG. 3 is positioned in the + X direction, the −X direction, the + Y direction, the −Y direction, and directly above the magnetoresistive effect element 20.

  FIG. 4 shows a state when the magnet 30 is positioned in the + X direction with respect to the magnetoresistive effect element 20. Part of the external magnetic field generated from the magnet 30 is collected in the first magnetic body 13, and the magnetic flux is directed from the facing surface 13 a 1 of the first magnetic body 13 toward the facing surface 14 a 1 of the second magnetic body 14. Is guided. At this time, a horizontal magnetic field component H4 in a direction close to the −X direction enters the magnetoresistive effect element 20 positioned between the first magnetic body 13 and the second magnetic body 14. Since the magnetization direction (PIN direction) of the pinned magnetic layer 62 of the magnetoresistive effect element 20 is the + X direction, when the horizontal magnetic field component H4 flows in, the magnetization direction of the pinned magnetic layer 62 of the magnetoresistive effect element 20 The relationship between the (PIN direction) and the magnetization direction of the free magnetic layer 64 is substantially antiparallel, and the electric resistance value of the magnetoresistive element 20 is increased.

  FIG. 5 shows a state where the magnet 30 is positioned in the −X direction with respect to the magnetoresistive effect element 20. A part of the external magnetic field generated from the magnet 30 is collected in the second magnetic body 14, and the magnetic flux is directed from the facing surface 14 a 1 of the second magnetic body 14 toward the facing surface 13 a 1 of the first magnetic body 13. Is guided. At this time, a horizontal magnetic field component H5 in a direction close to the + X direction enters the magnetoresistive effect element 20 positioned between the first magnetic body 13 and the second magnetic body 14. Since the magnetization direction (PIN direction) of the pinned magnetic layer 62 of the magnetoresistive effect element 20 is the + X direction, the magnetization direction of the pinned magnetic layer 62 of the magnetoresistive effect element 20 by the flow of the horizontal magnetic field component H5. The relationship between the (PIN direction) and the magnetization direction of the free magnetic layer 64 is substantially parallel, and the electric resistance value of the magnetoresistive effect element 20 becomes small.

  As shown in the circuit configuration of FIG. 10, a bridge circuit including the magnetoresistive effect element 20 is configured. As shown in FIG. 10, two magnetoresistive elements 20 are provided, but one may be used. When a plurality of magnetoresistive elements 20 are provided, for example, the magnetoresistive elements 20 are arranged in parallel in the X direction, but the arrangement of the magnetoresistive elements 20 is not limited. The fixed resistance element 25 connected in series with the magnetoresistive effect element 20 is an element whose electric resistance value does not vary with respect to an external magnetic field. As another example, instead of the fixed resistance element 25, a magnetoresistive effect element in which the magnetization direction of the fixed magnetic layer faces the −X direction, which is the opposite direction to the magnetoresistive effect element 20, may be used. . As a result, the output (differential potential) can be increased. Reference numeral 26 shown in FIG. 10 is an input terminal, and reference numeral 27 is a ground terminal.

  As shown in FIG. 10, two output extraction sections 22 and 23 provided in the bridge circuit are connected to a differential amplifier 28, and further the differential amplifier 28 is connected to an external output terminal 24 via a comparison circuit 29. .

  As described with reference to FIGS. 4 and 5, when the magnet 30 is positioned in the + X direction or the −X direction with respect to the magnetoresistive effect element 20, the fluctuation of the electric resistance value of the magnetoresistive effect element 20 increases, and as a result, The potentials of the output extraction units 22 and 23 vary greatly from the midpoint potential. For this reason, the differential potential output from the differential amplifier 28 also fluctuates greatly, and an ON signal is generated when the differential potential exceeds or falls below the reference potential (threshold value) determined by the comparison circuit 29. . The ON signal indicating that an external magnetic field from the magnet 30 has been detected is output from the external output terminal 24.

  In the present embodiment, the first magnetic body 13 and the second magnetic body 14 are provided on both sides in the X direction of the magnetoresistive effect element 20, so that the magnet 30 is X with respect to the magnetoresistive effect element 20. When positioned in the direction, the magnetic flux density of the horizontal magnetic field component can be amplified, and the detection range of the magnet 30 in the + X direction and the −X direction can be expanded as compared with the conventional case. The magnetic flux density can be increased by several mT.

  Subsequently, FIG. 6 shows a state when the magnet 30 is positioned in the + Y direction with respect to the magnetoresistive effect element 20. A part of the external magnetic field generated from the magnet 30 is collected in the second magnetic body 14, and the magnetic flux is directed from the facing surface 14 a 1 of the second magnetic body 14 toward the facing surface 13 a 1 of the first magnetic body 13. Is guided. At this time, a horizontal magnetic field component H6 inclined from the −Y direction to the + X direction enters the magnetoresistive effect element 20 positioned between the first magnetic body 13 and the second magnetic body. That is, the direction of the horizontal magnetic field component acting from the −Y direction as in the prior art in which the first magnetic body 13 and the second magnetic body 14 are not provided is changed to the first magnetic body 13 and the second magnetic body 13 as in this embodiment. By providing the magnetic body 14, the direction can be changed from the −Y direction to the + X direction. Since the magnetization direction (PIN direction) of the pinned magnetic layer 62 of the magnetoresistive effect element 20 is the + X direction, when the horizontal magnetic field component H6 flows in, the magnetization direction of the pinned magnetic layer 62 of the magnetoresistive effect element 20 The angle between the (PIN direction) and the magnetization direction of the free magnetic layer 64 becomes smaller than 90 °, and thus the electric resistance value of the magnetoresistive effect element 20 becomes smaller than the intermediate value.

  FIG. 7 shows a state when the magnet 30 is positioned in the −Y direction with respect to the magnetoresistive effect element 20. Part of the external magnetic field generated from the magnet 30 is collected in the first magnetic body 13, and the magnetic flux is directed from the facing surface 13 a 1 of the first magnetic body 13 toward the facing surface 14 a 1 of the second magnetic body 14. Is guided. At this time, a horizontal magnetic field component H7 inclined from the + Y direction to the −X direction enters the magnetoresistive element 20 positioned between the first magnetic body 13 and the second magnetic body 14. Since the magnetization direction (PIN direction) of the pinned magnetic layer 62 of the magnetoresistive effect element 20 is the + X direction, when the horizontal magnetic field component H7 flows in, the magnetization direction of the pinned magnetic layer 62 of the magnetoresistive effect element 20 The angle between the (PIN direction) and the magnetization direction of the free magnetic layer 64 becomes larger than 90 °, and the electric resistance value of the magnetoresistive effect element 20 becomes larger than the intermediate value.

  Therefore, even when the magnet 30 is positioned in the + Y direction and the −Y direction with respect to the magnetoresistive effect element 20 as shown in FIG. 6 and FIG. 7, the output from the midpoint potential in the output extraction portions 22 and 23 shown in FIG. The potential fluctuation amount can be increased as compared with the conventional case, and the ON signal can be generated by the comparison circuit 29.

  As shown in FIG. 6 and FIG. 7, when the magnet 30 is positioned in the + Y direction and the −Y direction with respect to the magnetoresistive effect element 20, the horizontal direction in the + Y direction or the −Y direction from the magnet 30 toward the magnetoresistive effect element 20. Because of the influence of the magnetic field component, the horizontal magnetic field components H6 and H7 are more likely to approach the + Y direction and the -Y direction than the horizontal magnetic field components H4 and H5 shown in FIGS. Therefore, the differential potential (absolute value) obtained from the differential amplifier 28 is smaller than when the magnet 30 is positioned in the + X direction and the −X direction with respect to the magnetoresistive effect element 20 as shown in FIGS. As shown in FIG. 3, the detection range in the Y direction in the region B tends to be shorter than the detection range in the X direction. In addition, the detection range in the Y direction can be reliably ensured, and the entire area around the magnetoresistive effect element 20 can be determined as the detection range as compared with the conventional case.

  In the present embodiment, the opposing surfaces 13a1 and 14a1 of the first magnetic body 13 and the second magnetic body 14 are shifted from each other in the Y direction in the drawing. For example, if the opposing surfaces 13a1 and 14a1 are not shifted from each other in the Y direction in the drawing and coincide with the X direction, the external magnetic field generated from the magnet 30 is either the first magnetic body 13 or the second magnetic body 14. It is considered that the horizontal magnetic field component guided between the facing surfaces 13a1 and 14a1 becomes very small. As in the present embodiment, by shifting the facing surfaces 13a1 and 14a1 of the first magnetic body 13 and the second magnetic body 14 in the Y direction, the center of the magnet 30 is positioned at the magnetoresistive effect element 20 as shown in FIG. 2, the external magnetic field is preferentially guided to the second magnetic body 14, and the center of the magnet 30 is positioned in the −Y direction with respect to the magnetoresistive effect element 20 as shown in FIG. 7. In this case, as a result of the external magnetic field being preferentially guided to the first magnetic body 13, horizontal magnetic field components H6 and H7 are appropriately generated between the facing surfaces 13a1 and 14a1.

  Alternatively, as shown in FIG. 6, when the magnet 30 is positioned in the vicinity of the magnetoresistive effect element 20, the magnet 30 faces in the Y direction near the opposed surfaces 13 a 1 and 14 a 1 of the first magnetic body 13 and the second magnetic body 14. The side surface is considered to be easily magnetized to the S pole and the N pole under the influence of the horizontal magnetic field component in the −Y direction from the magnet 30. At this time, the opposing surfaces 13a1 and 14a1 of the first magnetic body 13 and the second magnetic body 14 are arranged so as to be shifted from each other in the Y direction in the drawing, so that the N pole of the second magnetic body 14 shown in FIG. It is considered that the surface and the S pole surface of the first magnetic body 13 approach each other in the X direction, and the magnetic flux is easily guided efficiently from the second magnetic body 14 toward the first magnetic body 13. . Therefore, the magnetic flux density of the horizontal magnetic field components H6 and H7 entering the magnetoresistive effect element 20 can be increased, and even when the magnet 30 is positioned in the + Y direction and the −Y direction with respect to the magnetoresistive effect element 20, the magnetism is effectively magnetized. The resistance effect element 30 can be detected.

  In the present embodiment, the first magnetic body 13 and the second magnetic body 14 extend in the direction away from the X-direction extending portions 13b and 14b extending in the direction of the magnetoresistive effect element 20. Since the Y-direction extending portions 13c and 14c are provided, the horizontal magnetic field components H6 and H7 are appropriately generated from the X-direction extending portions 13b and 14b protruding in the direction of the magnetoresistive effect element 20. Even if the magnet 30 is separated from the magnetoresistive effect element 20, the Y-direction extending portions 13c and 14c are located closer to the magnet 30 than the magnetoresistive effect element 20, so that The magnetic flux collection effect can be appropriately increased by the Y direction extending portions 13c and 14c, and the detection range in the Y direction can be effectively increased.

  Next, FIG. 8 shows a state when the magnet 30 is positioned directly above the magnetoresistive effect element 20. As shown in FIG. 8, the upper surfaces 13a2, 14a2 of the Z-direction extending portions 13a, 14a of the first magnetic body 13 and the second magnetic body 14 are attached to the S pole, and the lower faces 13a3, 14a3 are attached to the N pole. Magnetized. In the present embodiment, the opposed surfaces 13a1 and 14a1 of the first magnetic body 13 and the second magnetic body 14 are arranged so as to be shifted in the Z direction shown in the drawing. For this reason, the N pole surface of the lower surface 13a3 of the first magnetic body 13 and the S pole surface of the upper surface 14a2 of the second magnetic body 14 can be brought closer to each other in the X direction. The horizontal magnetic field component H8 in a direction close to the −X direction can be guided from the N pole face of the second magnetic body 14 toward the S pole face of the second magnetic body 14, and the horizontal magnetic field component H8 can be guided to the first magnetic body 13 and the horizontal magnetic field component H8. The magnetoresistive effect element 20 positioned between the second magnetic bodies 14 can be made to enter.

  As a result, the electric resistance value of the magnetoresistive effect element 20 becomes large. Therefore, even when the magnet 30 is positioned immediately above the magnetoresistive effect element 20, the potentials of the output extraction portions 22 and 23 shown in FIG. The potential can be greatly varied from the potential, and an ON signal can be generated by the comparison circuit 29.

  In the present embodiment, the first magnetic body 13 and the second magnetic body 14 are arranged substantially parallel to the X direction and extending away from the magnetoresistive effect element 20 and shifted in the Z direction. X-direction extension portions 13b and 14b, and Z-direction extension portions 13a and 14a extending from the X-direction extension portions 13b and 14b in a direction substantially parallel to the Z direction and approaching the magnetoresistive element 20 The surfaces facing the inside through the magnetoresistive effect element 20 of the Z-direction extending portions 13a and 14a are the facing surfaces 13a1 and 14a1. As a result, the magnetic flux collection effect can be improved more appropriately, the horizontal magnetic field component H8 can be efficiently allowed to enter the magnetoresistive effect element 20, and the magnet 30 can be connected to the true element of the magnetoresistive effect element 20. Even if it is located above (or directly below), the magnet 30 can be detected more effectively.

  Of course, when the magnet 30 is in the region between the X direction and the Y direction, the horizontal magnetic field component approaching the + X direction or the −X direction enters the magnetoresistive effect element 20. The resistance value is appropriately larger or smaller than the intermediate value, an on signal can be generated, and the presence of the magnet 30 can be detected.

  As described above, the region immediately above or directly below the magnetoresistive effect element 20 that has been the blind spot region, and the + Y direction region and the −Y direction region as viewed from the magnetoresistive effect element 20 can all be made detectable regions. Therefore, it is possible to expand the detection range of the magnet 30 located on the XY plane as compared with the conventional case.

  Moreover, in the present embodiment, it is basically sufficient to use one magnetoresistive element 20 for the sensor unit for capturing the external magnetic field from the magnet 30, and even when a plurality of magnetoresistive elements are used, as shown in FIG. Thus, it is only necessary to construct one bridge circuit. Since the circuit configuration of FIG. 10 is the same as that of the conventional bipolar magnetic sensor, the detection range can be expanded using a simple circuit configuration without complication.

  In the above-described embodiment, the opposing surfaces 13a1 and 14a1 of the first magnetic body 13 and the second magnetic body 14 are arranged so as to be shifted from each other in the Y direction and the Z direction. The opposite surfaces 13a1 and 14a1 of the second magnetic body 14 are displaced only in the Y direction, and the opposed surfaces 13a1 and 14a1 of the first magnetic body 13 and the second magnetic body 14 are displaced only in the Z direction. Form may be sufficient.

  Further, for example, as shown in FIG. 6, the opposed surface 13 a 1 of the first magnetic body 13 and the opposed surface 14 a 1 of the second magnetic body 14 are shifted in the Y direction so as not to overlap in the X direction in plan view. Alternatively, it may be arranged so as to be shifted in the Y direction so as to partially overlap in the X direction. If the first magnetic body 13 and the second magnetic body 14 are shifted too much in the Y direction so as not to overlap in the X direction (for example, the side surface 13d of the first magnetic body 13 facing the + Y direction is 2), the horizontal magnetic field components H6 and H7 shown in FIGS. 6 and 7 are closer to the Y direction, and the magnet 30 is magnetized. Since the detection when the resistance effect element 20 is positioned in the Y direction cannot be performed properly, it is not preferable that the resistance effect element 20 is shifted too much. In FIG. 6, the side surface 13 d facing the + Y direction of the first magnetic body 13 and the side surface 14 d facing the −Y direction of the second magnetic body 14 coincide with the X direction shown in the figure. The shift amount between 14d is -1.0 to 0.0 mm (a positive value indicates a shift direction in which the opposing surfaces 13a1 and 14a1 partially overlap in the Y direction, and a negative value indicates that the opposing surfaces 13a1 and 14a1 are in the Y direction) It is preferable that the shift direction is separated without overlapping.

  In this embodiment, the first magnetic body 13 and the second magnetic body 14 are arranged point-symmetrically with the center 20a of the magnetoresistive element 20 as the rotation center. Accordingly, the detection range length in the + Y direction when the magnet 30 is positioned in the + Y direction with respect to the magnetoresistive effect element 20 is the same as the detection range length in the -Y direction when the magnet 30 is positioned in the -Y direction. Can be

  Next, for example, as shown in FIG. 2, in the side view, the facing surface 13a1 of the first magnetic body 13 and the facing surface 14a1 of the second magnetic body 14 are shifted in the Z direction so as not to overlap in the X direction. Even if it arrange | positions, it may be arrange | positioned by shifting in a Z direction so that it may partially overlap in a X direction. If the first magnetic body 13 and the second magnetic body 14 are shifted too much in the Z direction so as not to overlap in the X direction (for example, the lower surface of the Z-direction extending portion 13a of the first magnetic body 13). 13a3 is excessively shifted upward from the upper surface 14a2 of the Z-direction extending portion 14a of the second magnetic body 14), or if the overlapping regions in the X direction of the opposing surfaces 13a1 and 14a1 are too large, The horizontal magnetic field component H8 that enters the magnetoresistive element 20 becomes small, which is not preferable. In FIG. 2, the lower surface 13a3 of the Z-direction extension 13a of the first magnetic body 13 and the upper surface 14a2 of the Z-direction extension 14a of the second magnetic body 14 coincide with each other in the X direction. However, the shift amount between the upper and lower surfaces 13a2 and 14a2 is -0.5 to 0.5 mm (a positive value indicates a shift direction in which the opposing surfaces 13a1 and 14a1 partially overlap in the X direction, and a negative value indicates the opposing surface. It is preferable that 13a1 and 14a1 indicate a shifting direction in which they do not overlap in the X direction.

  As shown in FIG. 8, the magnetoresistive effect element 20 is provided at a position where it does not overlap the first magnetic body 13 in the X direction, while it overlaps the second magnetic body 14 in the X direction. However, the magnetoresistive effect element 20 may be arranged slightly upward. However, in the form of FIG. 8, the lower surface 13a3 of the Z-direction extension 13a of the first magnetic body 13 and the upper surface 14a2 of the Z-direction extension 14a of the second magnetic body 14 are magnetic pole surfaces, respectively. Since the horizontal magnetic field component H8 is easily guided from the lower surface 13a4 of the Z-direction extension portion 13a of the magnetic body 13 toward the upper surface 14a2 of the Z-direction extension portion 14a of the second magnetic body 14, the magnetoresistive effect element 20 is The first magnetic body 13 is preferably disposed in the vicinity of the lower surface 13a3 of the Z-direction extension 13a and the upper surface 14a2 of the Z-direction extension 14a of the second magnetic body 14. Further, as shown in FIG. 8, the magnetoresistive effect element 20 is positioned below the lower surface 13 a 3 of the Z-direction extending portion 13 a of the first magnetic body 13, or the Z-direction of the second magnetic body 14 of the magnetoresistive effect element 20. The horizontal magnetic field component H8 can be made to easily enter the magnetoresistive effect element 20 by disposing it at the position above the upper surface 14a2 of the extending portion 14a.

  Further, the first magnetic body 13 and the second magnetic body 14 may be, for example, in a flat plate shape, but as shown in FIG. 1, the Z-direction extension portions 13a and 14a and the X-direction extension portions 13b and 14b are used. In addition, the configuration including the Y-direction extending portions 13c and 14c can improve the magnetic flux collection effect and can efficiently cause the horizontal magnetic field component to enter the magnetic detection element 20, and is located on the XY plane. This is preferable in that the detection range of the magnet 30 can be appropriately expanded.

  FIG. 11 is a circuit configuration diagram of a magnetic detection device according to another embodiment. A magnetic detection device 100 shown in FIG. 11 includes a sensor unit 101 and an integrated circuit (IC) 102.

  The sensor unit 101 includes a first series circuit 106 in which a first magnetoresistance effect element 103 and a fixed resistance element 104 are connected in series via a first output extraction unit (connection unit) 105, and a second magnetoresistance A second series circuit 110 in which the effect element 107 and the fixed resistance element 108 are connected in series via a second output extraction unit (connection unit) 109 is provided.

  The integrated circuit 102 is provided with a third series circuit 114 in which a fixed resistance element 111 and a fixed resistance element 112 are connected in series via a third output extraction unit 113.

  The third series circuit 114 forms a bridge circuit with the first series circuit 106 and the second series circuit 110 as a common circuit.

  As shown in FIG. 11, the integrated circuit 102 is provided with an input terminal (power source) 119, a ground terminal 120, and two external output terminals 121 and 122.

  As shown in FIG. 11, one differential amplifier (differential output unit) 125 is provided in the integrated circuit 102, and either the + input unit or the −input unit of the differential amplifier 125 is connected to the third input unit. A third output extraction unit 113 of the series circuit 114 is connected.

  The first output extraction unit 105 of the first series circuit 106 and the second output extraction unit 109 of the second series circuit 110 are respectively connected to the input unit of the first switch circuit 126, and the output unit of the first switch circuit 126 is The differential amplifier 35 is connected to either the −input portion or the + input portion (the input portion on the side where the third output extraction portion 113 is not connected).

  As shown in FIG. 11, the output section of the differential amplifier 125 is connected to a Schmitt trigger type comparator 128, and the output section of the comparator 128 is connected to the input section of a second switch circuit (second connection switching section) 129. Further, the output side of the second switch circuit 129 is connected to the first external output terminal 121 and the second external output terminal 122 through two latch circuits and an FET circuit, respectively.

  Further, as shown in FIG. 11, a third switch circuit 130 is provided in the integrated circuit 102. The output portion of the third switch circuit 130 is connected to the ground terminal 120, and one end portions of the first series circuit 106 and the second series circuit 110 are connected to the input portion of the third switch circuit 130. .

  Further, as shown in FIG. 11, an interval switch circuit 131 and a clock circuit 133 are provided in the integrated circuit 102. When the switch of the interval switch circuit 131 is turned off, the power supply to the integrated circuit 102 is stopped. The on / off of the switch of the interval switch circuit 131 is interlocked with the clock signal from the clock circuit 133, and the interval switch circuit 131 has a power saving function of intermittently energizing.

  The clock signal from the clock circuit 133 is also output to the first switch circuit 126, the second switch circuit 129, and the third switch circuit 130.

  The first magnetoresistive effect element 103 is a magnetoresistive effect element that exhibits a magnetoresistive effect based on, for example, a change in the intensity of an external magnetic field in the + X direction, while the second magnetoresistive effect element 107 is in the −X direction. It is a magnetoresistive element that exhibits a magnetoresistive effect based on a change in magnetic field strength of an external magnetic field.

  As illustrated in FIGS. 12 and 13, when an external magnetic field in the + X direction acts, the resistance value of the first magnetoresistance effect element 103 varies, but the resistance value of the second magnetoresistance effect element 107 does not vary ( That is, it acts as a fixed resistor).

  On the other hand, as will be described with reference to FIGS. 12 and 13, when an external magnetic field in the −X direction acts, the resistance value of the second magnetoresistive element 107 varies, but the resistance value of the first magnetoresistive element 103 is Does not fluctuate (ie act as a fixed resistance).

  For example, the magnetization directions (PIN directions) of the pinned magnetic layers of the first magnetoresistive element 103 and the second magnetoresistive element 107 are both in the −X direction.

  On the other hand, the magnetization direction of the free magnetic layer differs between the first magnetoresistive effect element 103 and the second magnetoresistive effect element 107 in a no magnetic field state (a state in which no external magnetic field acts). The magnetization direction of the free magnetic layer of the first magnetoresistive effect element 103 is the -X direction in the absence of a magnetic field, and the magnetization direction of the free magnetic layer of the second magnetoresistance effect element 107 is the + X direction in the absence of a magnetic field. .

  FIG. 12 is an RH curve showing the hysteresis characteristics of the first magnetoresistive element 103. As shown in FIG. 12, the first magnetoresistance effect element 103 is formed with a hysteresis loop HR surrounded by the curves HR1 and HR2 with respect to the change in the magnetic field strength of the external magnetic field in the + X direction. The intermediate value of the maximum resistance value and the minimum resistance value of the first magnetoresistive effect element 103, and the center value of the spread width of the hysteresis loop HR is the “midpoint” of the hysteresis loop HR. The magnitude of the first interlayer coupling magnetic field Hin1 is determined by the strength of the magnetic field from the midpoint of the hysteresis loop HR to the line of the external magnetic field H = 0 (Oe). As shown in FIG. 3, in the first magnetoresistance effect element 103, the first interlayer coupling magnetic field Hin1 is shifted in the magnetic field direction in the + X direction.

  FIG. 13 is an RH curve showing the hysteresis characteristic of the second magnetoresistance effect element 107. As shown in FIG. 13, the second magnetoresistance effect element 107 is formed with a hysteresis loop HR surrounded by the curves HR3 and HR4 with respect to the change in the magnetic field strength of the external magnetic field in the −X direction. The intermediate value of the maximum resistance value and the minimum resistance value of the second magnetoresistance effect element 107, and the center value of the spread width of the hysteresis loop HR is the “midpoint” of the hysteresis loop HR. The magnitude of the second interlayer coupling magnetic field Hin2 is determined by the strength of the magnetic field from the midpoint of the hysteresis loop HR to the line of the external magnetic field H = 0 (Oe). As shown in FIG. 13, in the second magnetoresistive effect element 107, the second interlayer coupling magnetic field Hin2 is shifted in the magnetic field direction in the -X direction.

  4, 7, and 8, the electrical resistance value of the second magnetoresistive element 107 largely fluctuates largely, and at least the first switch circuit 126, the second switch circuit 129, and the third switch circuit 130 When switched from the state of FIG. 1 (switched), an ON signal is output from the second external output terminal 122. On the other hand, in the case of FIG. 5 and FIG. 6, the electrical resistance value of the first magnetoresistive element 103 largely fluctuates greatly, and at least the first switch circuit 126, the second switch circuit 129, and the third switch circuit 130 are illustrated. In the state 1, an ON signal is output from the first external output terminal 121. In the present embodiment, it is detected that the magnet 30 is present in the region B in FIG. 3 by obtaining an ON signal without being particularly distinguished from either the first external output terminal 121 or the second external output terminal 122. it can.

  The magnetic detection device 10 of the present embodiment is used for measuring, for example, whether or not a person has placed the magnet 30 in the region B shown in FIG. Further, the magnet 30 may be a component incorporated in the magnetic detection device 10, and the magnet 30 is not the moving side but the fixed side, and the magnetic sensor 12, the first magnetic body 13, and the second shown in FIG. The substrate 11 having the magnetic body 14 may be on the moving side.

The perspective view of the magnetic detection apparatus in this embodiment, The side view which looked at the magnetic detection apparatus from the arrow direction of FIG. The top view for demonstrating the detection range of the magnet in this embodiment, A plan view when the magnet is positioned in the + X direction with respect to the magnetoresistive element, A plan view when the magnet is positioned in the −X direction with respect to the magnetoresistive element, A plan view when the magnet is positioned in the + Y direction with respect to the magnetoresistive element, The top view when a magnet is located in -Y direction with respect to a magnetoresistive effect element, Side view when the magnet is located directly above the magnetoresistive element, Sectional drawing which shows the laminated structure of the magnetoresistive effect element in this embodiment, The circuit block diagram of the magnetic detection apparatus in this embodiment, The circuit block diagram of the magnetic detection apparatus in other embodiment, RH curve of the first magnetoresistive element, RH curve of the second magnetoresistive element, A plan view showing a conventional magnet detection range, A side view when the magnet is positioned in the + X direction with respect to the magnetoresistive effect element constituting the conventional magnetic detection device, The front view when a magnet is located in + Y direction with respect to the magnetoresistive effect element which comprises the conventional magnetic detection apparatus, A side view when the magnet is positioned directly above the magnetoresistive effect element constituting the conventional magnetic detection device,

Explanation of symbols

10, 100 Magnetic detection device 11 Substrate 12 Magnetic sensor 13 First magnetic body 13a, 14a Z-direction extension portion 13a1, 14a1 Opposing surface 13b, 14b X-direction extension portion 13c, 14c Y-direction extension portion 14 Second Magnetic body 20 Magnetoresistive effect element 22, 23, 105, 109, 113 Output extraction unit 24, 121, 122 External output terminal 25, 104, 108, 111, 112 Fixed resistance element 26, 119 Input terminal 27, 120 Ground terminal 28 , 125 differential amplifier 29 comparison circuit 30 magnet 30a (magnet) upper surface 30b (magnet) lower surface 61 antiferromagnetic layer 62 pinned magnetic layer 63 nonmagnetic layer 64 free magnetic layer 65 protective layer 101 sensor unit 102 integrated circuit 103 first 1 magnetoresistive effect element 107 second magnetoresistive effect element 126 first switch circuit 129 second switch circuit 13 0 third switch circuit 133 clock circuit H4 to H8 horizontal magnetic field components Hin1 and Hin2 interlayer coupling magnetic field PIN magnetization direction of pinned magnetic layer

Claims (5)

The lower surface and the upper surface are arranged at different height positions with respect to the magnet of the magnetized surface, and include a magnetoresistive effect element that varies in electric resistance value by receiving an external magnetic field from the magnet,
The magnetoresistive effect element has a structure in which at least a pinned magnetic layer, a free magnetic layer, and a nonmagnetic layer interposed between the pinned magnetic layer and the free magnetic layer are stacked in the height direction (Z direction). ,
The magnetization direction of the fixed magnetic layer is fixed in one direction of the X direction orthogonal to the Z direction, and the first magnetic body and the second magnetic material are spaced apart from each other in the X direction of the magnetoresistive element. And a magnetic body,
The opposing surfaces of the first magnetic body and the second magnetic body facing in the X direction are arranged to be shifted from each other in the Y direction perpendicular to the X direction and the Z direction.   The first magnetic body and the second magnetic body include an X-direction extending portion extending in a direction substantially parallel to the X direction and away from the magnetoresistive effect element, and an opposite of the X-direction extending portion. The magnetic detection device according to claim 1, further comprising a Y-direction extending portion extending in a direction substantially parallel to the Y direction from the opposite side of the surface side and away from each other.   3. The magnetic detection device according to claim 1, wherein opposing surfaces of the first magnetic body and the second magnetic body are arranged to be shifted in the Z direction. The lower surface and the upper surface are arranged at different height positions with respect to the magnet of the magnetized surface, and include a magnetoresistive effect element that varies in electric resistance value by receiving an external magnetic field from the magnet,
The magnetoresistive effect element has a structure in which at least a pinned magnetic layer, a free magnetic layer, and a nonmagnetic layer interposed between the pinned magnetic layer and the free magnetic layer are stacked in the height direction (Z direction). ,
The magnetization direction of the pinned magnetic layer is fixed in one direction of the X direction, and the first magnetic body and the second magnetic body are spaced apart on both sides of the magnetoresistive element in the X direction. Provided,
The opposing surfaces of the first magnetic body and the second magnetic body facing in the X direction are arranged to be shifted from each other in the Z direction.   Each of the first magnetic body and the second magnetic body extends in a direction substantially parallel to the X direction and away from the magnetoresistive effect element, and is disposed in an offset direction in the Z direction. A Z-direction extension portion extending in a direction substantially parallel to the Z direction from the X-direction extension portion and approaching the magnetoresistive element, and one of the Z-direction extension portions facing the X direction The magnetic detection device according to claim 3, wherein a surface is the facing surface.

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