JP5467209B2 - Magnetic sensor - Google Patents

Description

  The present invention relates to a magnetic sensor using a magnetoresistive effect element.

  In recent years, a magnetoresistive element (GMR element) using a giant magnetoresistive effect (GMR effect) has been used in a magnetic encoder (Patent Document 1). A magnetic sensor for flow rate detection using this magnetic encoder has been developed. This magnetic sensor is arranged at a predetermined interval to a magnet that is a magnetic flux generation source, and detects a magnetism when a magnetic flux generated from the magnet is applied.

JP 2008-151759 A

  In principle, when the gap (Gap) between the magnetic sensor and the magnetic flux generation source (magnet) increases, the magnetic flux diverges and the magnetic flux density decreases. As a result, it is considered that a sufficient magnetic flux density is not applied to the magnetic sensor and the magnetic sensor cannot be operated. On the other hand, there is a demand for miniaturization of a unit that accommodates a magnetic flux generation source and a magnetic sensor, and in order to improve the degree of freedom of unit design, the magnetic sensor can detect a magnetic flux even with a low magnetic flux density, that is, with a wide gap. Is strongly demanded.

  The present invention has been made in view of such a point, and provides a magnetic sensor using a magnetoresistive effect element that can detect a magnetic field even when a gap (Gap) between the magnetic flux generation source (magnet) is wide. The purpose is to do.

The magnetic sensor of the present invention has a meandering shape having a sensitive axis in a first direction, formed by sandwiching nonmagnetic layer by a pair of the free magnetic layer magnetization varies with respect to an external magnetic field, including a fixed magnetic layer First magnetoresistive element having a laminated structure that is not biased , and a first magnetic sensing element composed of a pair of soft magnetic films arranged so as to sandwich the first magnetoresistive element in plan view If has a meandering shape having a sensitive axis in a second direction different from said first direction, formed by sandwiching nonmagnetic layer by a pair of the free magnetic layer magnetization varies with respect to an external magnetic field, the fixed magnetic layer A second magnetoresistive element having a laminated structure that does not include a bias and a pair of soft magnetic films arranged to sandwich the second magnetoresistive element in plan view A sensing element, Is provided on the first substrate, wherein the first magnetoresistive element second magnetoresistive element are connected in series, constitute a bridge circuit in which the middle point potential is taken out from therebetween, said first magnetoresistive In each of the element and the second magnetoresistive element, when an external magnetic field in the sensitivity axis direction acts, the magnetization direction of the pair of free magnetic layers faces the direction of the external magnetic field and approaches parallel, and the resistance value decreases . It is characterized by that.

  According to this configuration, the yoke effect is exhibited for an external magnetic field in a specific direction, and the shield effect is exhibited for an external magnetic field in a direction different from the specific direction. Thereby, even if the space | interval (Gap) between magnetic flux generation sources (magnets) is wide, a magnetic detection is possible. In addition, according to this configuration, magnetic sensing elements having different sensitivity axis directions (first magnetic sensing element, second magnetic sensing element) are arranged, so even in the environment where external magnetic fields in different directions coexist, individual weak magnetic fields It is possible to detect the external magnetic field in the sensitivity axis direction with high sensitivity. Thereby, the magnetic detection of the magnetic flux generation source (magnet) of a complicated shape can be performed correctly.

  In the magnetic sensor of the present invention, it is preferable that the first direction and the second direction are orthogonal to each other.

  In the magnetic sensor of the present invention, the magnetic sensor is disposed at a distance from a magnetic flux generation source that is rotatable with respect to the rotation center, and the rotation direction and the radial direction about the rotation center are the first direction and the second direction. It is preferable that In this case, the interval is preferably 7 mm or more.

  In the magnetic sensor of the present invention, the material constituting the soft magnetic film is preferably selected from the group consisting of CoZrNb, NiFe, Co alloy, and an alloy containing Ni and Fe.

  The magnetic sensor of the present invention has a meander shape having a sensitivity axis in a first direction, and has a laminated structure in which a nonmagnetic layer is sandwiched between a pair of free magnetic layers whose magnetization varies with an external magnetic field. A magnetoresistive element, and a first magnetic sensing element composed of a pair of soft magnetic films arranged so as to sandwich the first magnetoresistive element in plan view; and a second magnetic sensor different from the first direction. A second magnetoresistive element having a meander shape having a sensitivity axis in the direction and having a laminated structure in which a nonmagnetic layer is sandwiched between a pair of free magnetic layers whose magnetization varies with respect to an external magnetic field; A second magnetic sensing element composed of a pair of soft magnetic films arranged so as to sandwich the second magnetoresistive effect element is provided on the same substrate and constitutes a bridge circuit. Distance between (magnet) ( Even ap) wide can be magnetically detected.

It is a figure which shows the magnetic sensor which concerns on embodiment of this invention. It is a figure for demonstrating the magnetoresistive effect element in the magnetic sensor which concerns on embodiment of this invention. It is a figure for demonstrating the space | interval (Gap) between the magnetic sensor which concerns on Embodiment 1 of this invention, and a magnetic flux generation source (magnet). It is a figure for demonstrating the circuit in the magnetic sensor which concerns on embodiment of this invention. (A), (b) is a figure which shows the magnetic field-resistance value characteristic of the magnetoresistive effect element based on Embodiment of this invention. It is a figure which shows the magnetic detection output by one magnetic detection element which does not have the structure of this invention. (A) is a figure which shows the magnetic detection output at the time of detecting the (theta) component by the magnetic sensor which concerns on Embodiment 1 of this invention, (b) is based on the magnetic sensor which concerns on Embodiment 1 of this invention. It is a figure which shows the magnetic detection output at the time of detecting R component. (A) is a figure which shows the output of the midpoint voltage of (theta) component detection element and R component detection element in the magnetic sensor which concerns on Embodiment 1 of this invention, (b) is embodiment of this invention 2 is a diagram showing a magnetic detection output of the magnetic sensor according to FIG. (A) is a figure for demonstrating the effect about the magnetic sensor which concerns on Embodiment 1 of this invention, (b) demonstrates the effect about the magnetic sensor which concerns on Embodiment 2 of this invention. FIG. It is a figure for demonstrating the space | interval (Gap) between the magnetic sensor which concerns on Embodiment 2 of this invention, and a magnetic flux generation source (magnet). It is a figure which shows the magnetic detection output by one magnetic detection element which does not have the structure of this invention. (A) is a figure which shows the magnetic detection output at the time of detecting the (theta) component by the magnetic sensor which concerns on Embodiment 2 of this invention, (b) is based on the magnetic sensor which concerns on Embodiment 2 of this invention. It is a figure which shows the magnetic detection output at the time of detecting R component. (A) is a figure which shows the output of the midpoint voltage of (theta) component detection element and R component detection element in the magnetic sensor which concerns on Embodiment 2 of this invention, (b) is Embodiment of this invention FIG. 6 is a diagram showing a magnetic detection output of a magnetic sensor according to FIG. It is a figure which shows the magnetoresistive effect element used for the magnetic sensor which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a plan view showing a magnetic sensor according to an embodiment of the present invention. FIG. 2 is a diagram for explaining a magnetoresistive element in the magnetic sensor according to the embodiment of the present invention.

  As shown in FIG. 1, a first element 2 that is a magnetic detection element and a second element 3 that is a magnetic detection element are provided on a substrate 1 (on the same substrate). The first element 2 includes a magnetoresistive effect element 21 whose resistance value is changed by application of an external magnetic field, and a pair of soft magnetic films 22 arranged so as to sandwich the magnetoresistive effect element 21 in plan view. Yes. The second element 3 includes a magnetoresistive effect element 31 whose resistance value is changed by application of an external magnetic field, and a pair of soft magnetic films 32 arranged so as to sandwich the magnetoresistive effect element 31 in plan view. Has been. As the substrate 1, a substrate used for a normal printed wiring board can be used. Reference numeral 4 in the figure indicates an electrode pad.

  The magnetoresistive elements 21 and 31 each have a meander shape having a sensitivity axis in a specific direction. The magnetoresistive element 21 has a meander shape having a sensitivity axis in the arrow X direction shown in FIG. That is, as shown in FIG. 2, the magnetoresistive effect element 21 has a straight portion 21a formed substantially in parallel and a connecting portion 21b connecting the straight portions 21a. A direction (arrow X direction) orthogonal to the extending direction of the straight line portion 21a is the sensitivity axis direction. The magnetoresistive effect element 31 has a meander shape having a sensitivity axis in the arrow Y direction shown in FIG. Similarly, the magnetoresistive effect element 31 has a straight portion formed substantially in parallel and a connecting portion that connects the straight portions. The direction (arrow Y direction in FIG. 2) orthogonal to the extending direction of the straight line portion is the sensitivity axis direction. In FIG. 1, the sensitivity axis direction (arrow X direction) of the magnetoresistive effect element 21 and the sensitivity axis direction (arrow Y direction) of the magnetoresistive effect element 31 are orthogonal to each other.

Here, the present inventors examined the relationship between the pattern width (D ₁ ) of the magnetoresistive effect elements 21 and 31 and the detected magnetic field shift amount. As a result, it was found that the sensitivity is higher as the element pattern width is relatively larger with respect to the magnetic field in the sensitivity axis direction, and the sensor operates with a relatively small magnetic field. From such a viewpoint, the widths (element pattern widths) of the magnetoresistive effect elements 21 and 31 are preferably 2 μm to 10 μm.

  As the magnetoresistive effect elements 21 and 31, a TMR element (tunnel magnetoresistive effect element), a GMR element (giant magnetoresistive effect element), or the like can be used. For example, as the GMR element, a GMR element or a TMR element having a multilayer structure in which a nonmagnetic layer is sandwiched between a pair of free magnetic layers each having a magnetization variation with respect to an external magnetic field can be used. That is, as shown in FIG. 14, the magnetoresistive effect elements 21 and 31 have a laminated structure of free magnetic layer / nonmagnetic layer / free magnetic layer. Here, Cu, etc. are mentioned as a material which comprises a nonmagnetic layer. Moreover, as a material which comprises a free magnetic layer, soft magnetic materials, such as a Ni-Fe alloy, are mentioned. The magnetoresistive elements 21 and 31 may have at least a laminated structure of free magnetic layer / nonmagnetic layer / free magnetic layer, and other layers may be provided. Further, the thickness of the free magnetic layer is preferably 1 nm to 6 nm, and the thickness of the nonmagnetic layer is preferably 1.8 nm to 2.6 nm.

  Since the magnetoresistive effect elements 21 and 31 used here do not need to detect a magnetic field from a specific direction due to the installation of the sensor in the apparatus and do not need to determine the polarity, the fixed magnetic layer (pinned layer) Is used, and a laminated structure of free magnetic layer / nonmagnetic layer / free magnetic layer is employed. For this reason, it is not necessary to form a pinned magnetic layer (pinned layer) by applying a magnetic field under heating in the manufacturing process. Thereby, a magnetoresistive effect element can be patterned on a board | substrate by photolithography and an etching, and a manufacturing process can be simplified. Moreover, since patterning can be performed by photolithography, the magnetoresistive effect element can be patterned even in a minute region.

  For example, when forming a free magnetic layer or a nonmagnetic layer, after depositing a free magnetic layer material on a substrate, forming a resist layer thereon, patterning by photolithography and etching, and forming a free magnetic layer The resist layer is removed.

  The pair of soft magnetic films 22 and 32 arranged so as to sandwich the magnetoresistive effect elements 21 and 31 amplifies an external magnetic field in a specific direction and attenuates an external magnetic field in a direction different from the specific direction. That is, the soft magnetic films 22 and 32 exhibit a yoke effect with respect to an external magnetic field in a specific direction, and shield effect with respect to an external magnetic field in a direction different from the specific direction (direction orthogonal to the specific direction). Demonstrate. The soft magnetic film 22 amplifies the external magnetic field in the sensitivity axis direction (arrow X direction) and shields the external magnetic field in the direction orthogonal to the sensitivity axis direction (arrow Y direction). On the other hand, the soft magnetic film 32 amplifies the external magnetic field in the sensitivity axis direction (arrow Y direction) and shields the external magnetic field in the direction orthogonal to the sensitivity axis direction (arrow X direction). The material constituting the soft magnetic film is preferably selected from the group consisting of CoZrNb, NiFe, Co alloy, and an alloy containing Ni and Fe.

Here, the inventors examined the relationship between the pattern widths (D ₂ , D ₃ ) of the soft magnetic films 22 and 32 and the external magnetic flux density (G) detected by the sensor. As a result, it was found that as the pattern width of the soft magnetic film becomes wider, the detection magnetic field of the sensor becomes smaller (higher sensitivity of the sensor). For this reason, from the viewpoint of increasing the sensitivity of the sensor, the pattern widths (D ₂ , D ₃ ) of the soft magnetic films 22 and 32 are preferably 50 μm to 150 μm.

In addition, the inventors examined the relationship between the pattern width (D ₂ , D ₃ ) of the soft magnetic films 22 and 32 and the magnetic flux density gain. As a result, it was found that the amplification factor of the magnetic flux density increases as the pattern width of the soft magnetic film increases. For this reason, from the viewpoint of the amplification factor of the magnetic flux density, the pattern widths (D ₂ , D ₃ ) of the soft magnetic films 22 and 32 are set to 50 μm or more, and are set according to the sensor sensitivity required for each magnetic detection system. can do.

  From the above results, the width of the soft magnetic film is preferably 50 μm or more in consideration of the high sensitivity of the sensor and the gain of the magnetic flux density. The thickness of the soft magnetic film is preferably 0.5 μm or more.

  In the individual magnetic sensing elements (first element 2 and second element 3) of the magnetic sensor of the present invention, the external magnetic field in the sensitivity axis direction (arrow X direction in the first element 2 and arrow Y direction in the second element 3). Acts, the magnetization direction of the pair of free magnetic layers is directed to the external magnetic field direction. Thereby, the magnetization direction of both free magnetic layers approaches parallel, and resistance value falls. Magnetism can be detected by using this change in resistance value as an output. At this time, an external magnetic field in a specific direction can be detected with high sensitivity by the pair of soft magnetic films sandwiching the magnetoresistive effect element. That is, the pair of soft magnetic films exerts a yoke effect on an external magnetic field in a specific direction, and has a shielding effect on an external magnetic field in a direction different from the specific direction (here, a direction orthogonal to the specific direction). Demonstrate. Thereby, even if the space | interval (Gap) between magnetic flux generation sources (magnets) is wide, a magnetic detection is possible.

  As shown in FIG. 1, by arranging magnetic sensing elements (first element 2 and second element 3) so that the sensitivity axis directions are orthogonal to each other, even in a weak external magnetic field in an environment where external magnetic fields in different directions coexist. It becomes possible to detect the external magnetic field in the direction of each sensitivity axis with high sensitivity.

(Embodiment 1)
In the present embodiment, the magnetic detection of the magnetic flux generation source (magnet) 41 as shown in FIG. 3 will be described. In FIG. 3, the distance between the magnet 41 and the magnetic sensor 42 (the distance between the magnet surface and the sensor center) is Gap. The magnet 41 (four-pole magnetic pole) is gear-shaped (substantially cross-shaped in cross section) and rotates around the rotation shaft 41a. That is, the magnetic sensor 42 is disposed with a gap from the magnet 41 that can rotate with respect to the rotation center (the rotation shaft 41a).

  Moreover, the magnetic sensor 42 has the structure shown in FIG. 1, and detects magnetism when the respective tip portions of the magnets 41 approach each other. That is, the magnetic sensor 42 magnetically detects the rotating magnet 41 at every rotation angle of 90 °. The arrow X direction in FIG. 1 is the magnet rotation direction (θ direction) about the rotation center, and the arrow Y direction in FIG. 1 is the magnet radial direction (R direction) about the rotation center. Therefore, the first element 2 in the magnetic sensor 42 is a θ component detection element that amplifies the component in the θ direction (θ component) and attenuates the component in the R direction (R component), and the second element in the magnetic sensor 42. Reference numeral 3 denotes an R component detection element that amplifies the component in the R direction (R component) and attenuates the component in the θ direction (θ component).

  In the magnetic sensor 42, the first element 2 and the second element 3 are electrically connected as shown in FIG. 4 to form a bridge circuit. The output of the magnetic sensor 42 is the midpoint potential of the R component detection element and the θ component detection element as shown in FIG. By using such a circuit, the magnet 41 having four teeth shown in FIG. 3 can be magnetically detected at every rotation angle of 90 °.

  Here, the output of the magnetic sensor 42 was examined when the distance between the magnet 41 and the magnetic sensor 42 shown in FIG. 3 was changed to 5.1 mm, 6.1 mm, and 7.1 mm, respectively. In addition, as a magnetoresistive effect element of the magnetic sensor 42, what has the characteristic shown to FIG. 5 (a), (b) was used. That is, in the magnetoresistive effect element of the magnetic sensor 42, the relationship between the magnetic field and the resistance value in the direction orthogonal to the sensitivity axis direction is a curve shown in FIG. It is a curve shown in FIG.5 (b).

  FIG. 6 is a diagram showing a case where the magnet 41 is magnetically detected by one magnetic detection element not having the configuration of the present invention. As can be seen from FIG. 6, the R component and the θ component are mixed. With such an output, particularly when the gap is 7.1 mm, it is difficult to accurately magnetically detect the four teeth (cannot be output as a periodic pulse).

  On the other hand, when the magnetic sensor 42 of the present invention is used, the output of only the first element 2 that is the θ component detection element is as shown in FIG. That is, the θ component is amplified and the R component is attenuated. Further, the output of only the second element 3 which is the R component detection element is as shown in FIG. That is, the R component is amplified and the θ component is attenuated. The midpoint potential of the θ component detection element and the R component detection element is as shown in FIG. FIG. 8A shows a gap with a gap of 5.1 mm and a gap with a gap of 7.1 mm. If this midpoint potential is a pulse output, the result is as shown in FIG. As can be seen from FIG. 8 (b), the four teeth could be accurately magnetically detected (gap could be output as a periodic pulse) regardless of whether the gap was 5.1 mm or 7.1 mm.

  Here, the magnet 41 shown in FIG. 3 and the magnetic sensor 42 that is a bipolar one-output having the configuration shown in FIG. 1 are prepared, and the distance between them (the distance between the magnet surface and the sensor center: Gap) is set. The duty of the sensor output pulse when it was set to 5.1 mm and 7.1 mm was examined (Example 1). The result is shown in FIG. Further, the duty of the sensor output pulse when the gap was set to 5.1 mm and 7.1 mm was examined using the magnetic sensor 42 having the bipolar output of the configuration shown in FIG. 1 (Example 2). The results are also shown in FIG. Further, using a magnetic sensor having the bipolar output of the configuration shown in FIG. 1 and not having the pair of soft magnetic films 22 and 32, Gap is 5.1 mm, 5.5 mm, 6.0 mm, 6.1 mm, 7 The duty of the sensor output pulse when .1 mm was set (Comparative Example 1). The results are also shown in FIG. Furthermore, using a magnetic sensor that has the configuration shown in FIG. 1 and is not provided with a pair of soft magnetic films 22 and 32, Gap was set to 5.1 mm, 5.5 mm, 5.8 mm, and 6.1 mm. The duty of the sensor output pulse at that time was examined (Comparative Example 2). The results are also shown in FIG. Furthermore, the sensor output when the gap is set to 5.1 mm, 5.5 mm, and 6.1 mm using a magnetic sensor that has the configuration shown in FIG. 1 and does not include the pair of soft magnetic films 22 and 32. The pulse duty was examined (Comparative Example 3). The results are also shown in FIG.

  As can be seen from FIG. 9A, in the case where the magnetic sensors of Examples 1 and 2 are used, the target duty (50% ± 20%) is satisfied up to Gap of 7.1 mm, and the magnet 41 has a magnetism. Detection is possible (gap dependence is slight). On the other hand, when the magnetic sensors of Comparative Examples 1 to 3 were used, the gap was 6.1 mm and the target duty (50% ± 20%) could not be satisfied (gap dependence was large).

  As described above, according to the magnetic sensor of the present invention, since the magnetic sensing elements (first element 2 and second element 3) having different sensitivity axis directions are arranged, a weak external environment in an environment where external magnetic fields in different directions coexist. Even with a magnetic field, an external magnetic field in the direction of each sensitivity axis can be detected with high sensitivity. Thereby, even if the gap between the magnets is wide, the magnetic detection of the magnetic flux generation source (magnet) having a complicated shape as shown in FIG. 3 can be performed accurately.

(Embodiment 2)
In the present embodiment, magnetic detection of a magnetic flux generation source (magnet) 43 as shown in FIG. 10 will be described. In FIG. 10, the distance between the magnet 43 and the magnetic sensor 42 (the distance between the magnet surface and the sensor center) is Gap. The magnet 43 (six-pole magnetic pole) has a ring shape having six protrusions 43a, and rotates around a rotation axis (broken line). That is, the magnetic sensor 42 is disposed with a gap from the magnet 43 that can rotate with respect to the rotation center (broken line).

  Moreover, the magnetic sensor 42 has the structure shown in FIG. 1, and detects magnetism when the respective tip portions of the magnets 43 approach each other. That is, the magnetic sensor 42 magnetically detects the rotating magnet 43 every rotation angle of 60 °. The arrow X direction in FIG. 1 is the magnet rotation direction (θ direction) about the rotation center, and the arrow Y direction in FIG. 1 is the magnet radial direction (R direction) about the rotation center. Therefore, the first element 2 in the magnetic sensor 42 is a θ component detection element that amplifies the component in the θ direction (θ component) and attenuates the component in the R direction (R component), and the second element in the magnetic sensor 42. Reference numeral 3 denotes an R component detection element that amplifies the component in the R direction (R component) and attenuates the component in the θ direction (θ component).

  In the magnetic sensor 42, the first element 2 and the second element 3 are electrically connected as shown in FIG. 4 to form a bridge circuit. The output of the magnetic sensor 42 is the midpoint potential of the R component detection element and the θ component detection element as shown in FIG. With such a circuit, it is possible to detect the magnetism at every rotation angle of 60 ° with respect to the magnet 43 having six teeth shown in FIG.

  Here, the output of the magnetic sensor 42 was examined when the distance between the magnet 43 and the magnetic sensor 42 shown in FIG. 10 was changed to 5.1 mm and 7.1 mm, respectively. In addition, as a magnetoresistive effect element of the magnetic sensor 42, what has the characteristic shown to FIG. 5 (a), (b) was used. That is, in the magnetoresistive effect element of the magnetic sensor 42, the relationship between the magnetic field and the resistance value in the direction orthogonal to the sensitivity axis direction is a curve shown in FIG. It is a curve shown in FIG.5 (b).

  FIG. 11 is a diagram showing a case where magnetism of the magnet 43 is detected by one magnetic sensing element not having the configuration of the present invention. As can be seen from FIG. 11, the R component and the θ component are mixed. With such an output, particularly when Gap is 7.1 mm, it is difficult to accurately magnetically detect the six protrusions (cannot be output as a periodic pulse).

  On the other hand, when the magnetic sensor 42 of the present invention is used, the output of only the first element 2 that is the θ component detection element is as shown in FIG. That is, the θ component is amplified and the R component is attenuated. Further, the output of only the second element 3 which is the R component detection element is as shown in FIG. That is, the R component is amplified and the θ component is attenuated. The midpoint potential of the θ component detection element and the R component detection element is as shown in FIG. If this midpoint potential is a pulse output, the result is as shown in FIG. As can be seen from FIG. 13 (b), even when the gap was 5.1 mm and the gap was 7.1 mm, the six protrusions could be accurately magnetically detected (can be output as periodic pulses). .

  Here, the magnet 43 shown in FIG. 10 and the magnetic sensor 42 which is the bipolar 1 output of the structure shown in FIG. 1 are prepared, and the distance between them (the distance between the magnet surface and the sensor center: Gap) is set. The duty of the sensor output pulse when it was set to 5.1 mm and 7.1 mm was examined (Example 3). The result is shown in FIG. Further, the duty of the sensor output pulse when the gap was set to 5.1 mm and 7.1 mm was examined using the magnetic sensor having the bipolar one output configured as shown in FIG. 1 (Example 4). The results are also shown in FIG. Furthermore, using a magnetic sensor that has the configuration shown in FIG. 1 and does not have a pair of soft magnetic films 22 and 32, Gap was set to 5.1 mm, 5.5 mm, 6.0 mm, and 7.1 mm. The duty of the sensor output pulse at that time was examined (Comparative Example 4). The results are also shown in FIG. Furthermore, the sensor output when the gap is set to 5.1 mm, 5.5 mm, and 6.1 mm using a magnetic sensor that has the configuration shown in FIG. 1 and does not include the pair of soft magnetic films 22 and 32. The pulse duty was examined (Comparative Example 5). The results are also shown in FIG. Furthermore, the sensor output when the gap is set to 5.1 mm, 5.5 mm, and 6.1 mm using a magnetic sensor that has the configuration shown in FIG. 1 and does not include the pair of soft magnetic films 22 and 32. The pulse duty was examined (Comparative Example 6). The results are also shown in FIG.

  As can be seen from FIG. 9B, when the magnetic sensors of the third and fourth embodiments are used, the target duty (50% ± 20%) is satisfied up to Gap of 7.1 mm, and the magnet 41 is magnetized. Detection is possible (gap dependence is slight). On the other hand, when the magnetic sensors of Comparative Examples 4 to 6 were used, the gap was 6.1 mm and the target duty (50% ± 20%) could not be satisfied (gap dependence was large).

  As described above, according to the magnetic sensor of the present invention, since the magnetic sensing elements (first element 2 and second element 3) having different sensitivity axis directions are arranged, a weak external environment in an environment where external magnetic fields in different directions coexist. Even with a magnetic field, an external magnetic field in the direction of each sensitivity axis can be detected with high sensitivity. Thereby, even if the gap between the magnets is wide, the magnetic detection of the magnetic flux generation source (magnet) having a complicated shape as shown in FIG. 10 can be accurately performed.

  The present invention is not limited to the first and second embodiments, and can be implemented with various modifications. For example, the materials, connection relations, thicknesses, sizes, manufacturing methods, and the like in the first and second embodiments can be changed as appropriate. In addition, the present invention can be implemented with appropriate modifications without departing from the scope of the present invention.

  The present invention can be applied to a magnetic sensor for detecting a flow rate.

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 1st element 3 2nd element 4 Electrode pad 21,31 Magnetoresistive effect element 21a Linear part 21b Connection part 22,32 Soft magnetic film 41,43 Magnet 41a Rotating shaft 42 Magnetic sensor 43a Protrusion part

Claims (5)

Non- biased stack without a pinned magnetic layer, having a meander shape with a sensitivity axis in the first direction and sandwiching a nonmagnetic layer between a pair of free magnetic layers whose magnetization varies with an external magnetic field A first magnetoresistive element having a structure, a first magnetic sensing element including a pair of soft magnetic films arranged so as to sandwich the first magnetoresistive element in plan view, and the first direction It has a meandering shape having a sensitive axis in a second direction different from the, formed by sandwiching nonmagnetic layer by a pair of the free magnetic layer magnetization varies with respect to an external magnetic field, are biased free of fixed magnetic layer A second magnetoresistive element having a non- stacked structure and a second magnetic sensing element composed of a pair of soft magnetic films arranged so as to sandwich the second magnetoresistive element in plan view. Provided on Ri, wherein the first magnetoresistive element second magnetoresistive element are connected in series, constitute a bridge circuit in which the middle point potential is taken out from therebetween, said first magnetoresistive element and the second magnetoresistance In each of the effect elements, when an external magnetic field in the sensitivity axis direction acts, the magnetization direction of the pair of free magnetic layers is directed in the direction of the external magnetic field and approaches a parallel, and the resistance value decreases. .   The magnetic sensor according to claim 1, wherein the first direction and the second direction are orthogonal to each other.   The magnetic sensor is disposed at a distance from a magnetic flux generation source that is rotatable with respect to a rotation center, and a rotation direction and a radial direction with respect to the rotation center are the first direction and the second direction. The magnetic sensor according to claim 2.   The magnetic sensor according to claim 3, wherein the distance is 7 mm or more.   The material constituting the soft magnetic film is selected from the group consisting of CoZrNb, NiFe, Co alloy, and an alloy containing Ni and Fe. The magnetic sensor described.

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