WO2011052596A1 - Magnetic sensor - Google Patents

Magnetic sensor Download PDF

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Publication number
WO2011052596A1
WO2011052596A1 PCT/JP2010/068981 JP2010068981W WO2011052596A1 WO 2011052596 A1 WO2011052596 A1 WO 2011052596A1 JP 2010068981 W JP2010068981 W JP 2010068981W WO 2011052596 A1 WO2011052596 A1 WO 2011052596A1
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WIPO (PCT)
Prior art keywords
magnetic
magnetic sensor
pair
sensor
magnetic field
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PCT/JP2010/068981
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French (fr)
Japanese (ja)
Inventor
秀人 安藤
真次 杉原
貴史 野口
徳男 中村
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アルプス電気株式会社
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Priority claimed from JP2009246851A external-priority patent/JP5467210B2/en
Priority claimed from JP2009246850A external-priority patent/JP5467209B2/en
Application filed by アルプス電気株式会社 filed Critical アルプス電気株式会社
Publication of WO2011052596A1 publication Critical patent/WO2011052596A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G01R33/09—Magnetoresistive devices
    • G01R33/091—Constructional adaptation of the sensor to specific applications
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N50/00—Galvanomagnetic devices
    • H10N50/10—Magnetoresistive devices

Definitions

  • the present invention relates to a magnetic sensor using a magnetoresistive effect element.
  • GMR element magnetoresistive effect element
  • GMR effect giant magnetoresistive effect
  • Patent Document 1 A magnetic sensor for flow rate detection using this magnetic encoder. 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.
  • 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 meander shape having a sensitivity axis in a specific direction, and has a magnetoresistive effect having 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. And a pair of soft magnetic films arranged so as to sandwich the magnetoresistive element in a plan view.
  • 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.
  • 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 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.
  • 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.
  • interval (Gap) between magnetic flux generation sources (magnets) is wide, a magnetic detection is possible.
  • magnetic sensing elements having different sensitivity axis directions first magnetic sensing element, second magnetic sensing element
  • 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.
  • the first direction and the second direction are orthogonal to each other.
  • the magnetoresistive element has a width of 2 ⁇ m to 10 ⁇ m.
  • the soft magnetic film preferably has a width of 50 ⁇ m to 150 ⁇ m.
  • 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 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.
  • the magnetic sensor of the present invention has a meander shape having a sensitivity axis in a specific direction, and has a magnetoresistive effect having 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. Since it includes a magnetic sensing element composed of an element and a pair of soft magnetic films arranged so as to sandwich the magnetoresistive effect element in plan view, the distance between the magnetic flux generating source (magnet) ( Magnetic detection is possible even if Gap) is wide.
  • 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 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 Gap,) wide can be magnetically detected.
  • (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.
  • FIG. 1 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. 2 It is a figure for demonstrating the space
  • (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.
  • 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. It is a figure which shows the relationship between the pattern width of a magnetoresistive effect element, and a detection magnetic field shift amount.
  • A) is a figure which shows the relationship between the pattern width of a soft magnetic film, and a sensor detection external magnetic flux density
  • (b) shows the relationship between the pattern width of a soft magnetic film and magnetic flux density gain.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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 this point of view, the width (element pattern width) of the magnetoresistive elements 21 and 31 is preferably 2 ⁇ m to 10 ⁇ m.
  • the pattern width (D 1 ) of the magnetoresistive effect elements 21 and 31 is changed from 2 ⁇ m to 20 ⁇ m.
  • the detected magnetic field shift amount (Oe) was examined by the magnetic field-resistance change characteristic (RH characteristic). The result is shown in FIG.
  • the sensitivity does not change depending on the element pattern width ( ⁇ mark). That is, for a magnetic field in a direction orthogonal to the sensitivity axis direction, the sensor operates with a relatively small magnetic field regardless of the element pattern width.
  • the sensitivity changes depending on the element pattern width ( ⁇ mark), and the sensitivity decreases as the element pattern width decreases. That is, with respect to the magnetic field in the sensitivity axis direction, the sensitivity is better as the element pattern width is relatively larger, and the sensor operates with a relatively smaller magnetic field.
  • the width (element pattern width) of the magnetoresistive effect elements 21 and 31 is preferably a width of 10 ⁇ m or less in which a difference in detection magnetic field between the X direction and the Y direction occurs.
  • the width (element pattern width) of the magnetoresistive effect elements 21 and 31 is preferably 2 ⁇ m to 10 ⁇ m.
  • a TMR element tunnel type magnetoresistive effect element
  • a GMR element giant magnetoresistive effect element
  • 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.
  • Cu, etc. are mentioned as a material which comprises a nonmagnetic layer.
  • the material constituting the free magnetic layer examples include soft magnetic materials such as Ni—Fe alloys.
  • 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.
  • 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.
  • the magnetoresistive effect elements 21 and 31 used here do not need to detect a magnetic field from a specific direction because of the sensor installation in the apparatus and do not need to determine the polarity
  • a magnetoresistive effect element can be patterned on a board
  • 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 disposed so as to sandwich the magnetoresistive effect elements 21 and 31 amplify an external magnetic field in a specific direction and attenuate 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).
  • 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.
  • the relationship between the pattern widths (D 2 , D 3 ) of the soft magnetic films 22 and 32 and the sensor detected external magnetic flux density (G) was examined. That is, the pattern width (D 2 , D 3 ) of a 0.5 ⁇ m thick soft magnetic film (CoZrNb film) is 0 (none), 50 ⁇ m, 100 ⁇ m, and 150 ⁇ m, and the sensor detected external magnetic flux density (G) at that time The magnetic field-resistance change characteristic (RH characteristic) was examined. The result is shown in FIG. As can be seen from FIG. 16A, the detection magnetic field of the sensor decreases as the pattern width of the soft magnetic film increases (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 ⁇ m or more, particularly 50 ⁇ m to 150 ⁇ m.
  • the pattern width (D 2 , D 3 ) of the soft magnetic films 22 and 32 was examined. That is, the pattern width (D 2 , D 3 ) of a 0.5 ⁇ m thick soft magnetic film (CoZrNb film) is set to 0 (Reference), 50 ⁇ m, 100 ⁇ m, and 150 ⁇ m, and the magnetic flux density amplification factor (Reference reference) at that time Were examined by magnetic field-resistance change characteristics (RH characteristics). The result is shown in FIG. As can be seen from FIG. 16B, the wider the pattern width of the soft magnetic film, the higher the amplification factor of the magnetic flux density (2 times when the width is 50 ⁇ m and 4 times when the width is 150 ⁇ m).
  • the pattern widths (D 2 , D 3 ) of the soft magnetic films 22 and 32 should be 50 ⁇ m or more and set according to the sensor sensitivity required for each magnetic detection system. Is preferred.
  • the width of the soft magnetic film is preferably 50 ⁇ m or more in consideration of the high sensitivity of the sensor and the viewpoint of the magnetic flux density gain.
  • the thickness of the soft magnetic film is preferably 0.5 ⁇ m or more.
  • 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.
  • 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
  • the present inventors examined the relationship between the pattern widths (D 2 , D 3 ) of the soft magnetic films 22 and 32 and the sensor detected external magnetic flux density (G). 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). Therefore, 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 ⁇ m to 150 ⁇ m.
  • 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 ⁇ m or more, and are set according to the sensor sensitivity required for each magnetic detection system. can do.
  • the width of the soft magnetic film is 50 ⁇ m or more in consideration of the high sensitivity of the sensor and the viewpoint of the magnetic flux density gain.
  • the thickness of the soft magnetic film is preferably 0.5 ⁇ m or more.
  • 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.
  • 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
  • the magnetic detection of the magnetic flux generation source (magnet) 41 as shown in FIG. 3 will be described.
  • 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).
  • the magnetic sensor 42 has the configuration shown in FIG. 1, and detects the magnetism when the tip portions of the magnets 41 are close to 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 ( ⁇ direction) about the rotation center
  • 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 ⁇ component detection element that amplifies the component in the ⁇ direction ( ⁇ 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 ⁇ direction ( ⁇ component).
  • 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 ⁇ component detection element as shown in FIG.
  • the magnet 41 having four teeth shown in FIG. 3 can be magnetically detected at every rotation angle of 90 °.
  • 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.
  • 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 magnetism of the magnet 41 is detected by one magnetic sensing element not having the configuration of the present invention.
  • the R component and the ⁇ 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).
  • the output of only the first element 2 which is the ⁇ component detection element is as shown in FIG. That is, the ⁇ component is amplified and the R component is attenuated.
  • 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 ⁇ component is attenuated.
  • the midpoint potential of the ⁇ 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.
  • 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.
  • 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.
  • 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.
  • the duty of the sensor output pulse at that time was examined (Comparative Example 2).
  • the results are also shown in FIG.
  • 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.
  • the target duty 50% ⁇ 20%
  • the magnet 41 has a magnetism. Detection is possible (gap dependence is slight).
  • the gap was 6.1 mm and the target duty (50% ⁇ 20%) could not be satisfied (gap dependence was large).
  • 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.
  • 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).
  • the magnetic sensor 42 has the configuration shown in FIG. 1, and detects the magnetism when the tips 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 ( ⁇ direction) about the rotation center
  • 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 ⁇ component detection element that amplifies the component in the ⁇ direction ( ⁇ 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 ⁇ direction ( ⁇ component).
  • the first element 2 and the second element 3 are electrically connected as shown in FIG. 4 and constitute a bridge circuit.
  • the output of the magnetic sensor 42 is the midpoint potential of the R component detection element and the ⁇ 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.
  • 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.
  • 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.
  • the R component and the ⁇ 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).
  • the output of only the first element 2 which is the ⁇ component detection element is as shown in FIG. That is, the ⁇ 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 ⁇ component is attenuated.
  • the midpoint potential of the ⁇ 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). .
  • 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.
  • 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.
  • the target duty 50% ⁇ 20%
  • the magnetism of the magnet 43 is increased. Detection is possible (gap dependence is slight).
  • the gap was 6.1 mm and the target duty (50% ⁇ 20%) could not be satisfied (gap dependence was large).
  • 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.
  • the materials, connection relations, thicknesses, sizes, manufacturing methods, and the like in the first and second embodiments can be changed as appropriate.
  • 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.

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  • Condensed Matter Physics & Semiconductors (AREA)
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Abstract

Disclosed is a magnetic sensor that uses a magnetoresistance effect element and is capable of magnetic detection even if there is a wide spacing between the magnetic sensor and a magnetic flux source. The magnetic sensor is characterized by being provided, upon the same substrate, with a first magnetic detection element that is formed by a first magnetoresistance effect element, which has a meandering shape with a sensitivity axis in a first direction and has a layered structure that is formed by sandwiching a nonmagnetic layer between a pair of free magnetic layers with a magnetization that fluctuates with respect to an external magnetic field, and a pair of soft magnetic films that are disposed in a manner so as to sandwich the aforementioned first magnetoresistance effect element when viewed from above; and a second magnetic detection element that is formed by a second magnetoresistance effect element, which has a meandering shape with a sensitivity axis in a second direction differing from the aforementioned first direction and has a layered structure that is formed by sandwiching a nonmagnetic layer between a pair of free magnetic layers with a magnetization that fluctuates with respect to the external magnetic field, and a pair of soft magnetic films that are disposed in a manner so as to sandwich the aforementioned second magnetoresistance effect element when viewed from above.

Description

磁気センサMagnetic sensor
　本発明は、磁気抵抗効果素子を用いた磁気センサに関する。 The present invention relates to a magnetic sensor using a magnetoresistive effect element.
　近年、巨大磁気抵抗効果（ＧＭＲ効果）を利用した磁気抵抗効果素子（ＧＭＲ素子）が磁気エンコーダに使用されている（特許文献１）。そして、この磁気エンコーダを応用した流量検知用の磁気センサが開発されている。この磁気センサは、磁束発生源である磁石に所定の間隔をおいて配置され、磁石から発生する磁束が印加されることにより磁気検知する。 Recently, a magnetoresistive effect element (GMR element) using a giant magnetoresistive effect (GMR effect) has been used for 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.
特開２００８－１５１７５９号公報JP 2008-151759 A
　上記のような磁気センサは、原理的に磁束発生源（磁石）との間の間隔（Ｇａｐ）が広がると、磁束が発散して磁束密度が小さくなる。その結果、磁気センサに十分な磁束密度が印加されず動作できなくなることが考えられる。一方で、磁束発生源及び磁気センサを収容するユニットには小型化の要求があり、ユニット設計の自由度を向上させるために、磁気センサには、低磁束密度検知、すなわち広いＧａｐでも磁気検知できることが強く求められている。 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.
　本発明はかかる点に鑑みてなされたものであり、磁束発生源（磁石）との間の間隔（Ｇａｐ）が広くても磁気検知することができる、磁気抵抗効果素子を用いた磁気センサを提供することを目的とする。 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.
　本発明の磁気センサは、特定の方向に感度軸を持つミアンダ形状を有し、外部磁界に対して磁化変動する一対のフリー磁性層で非磁性層を挟持してなる積層構造を有する磁気抵抗効果素子と、平面視において前記磁気抵抗効果素子を挟持するように配置された一対の軟磁性膜と、で構成された磁気検知素子を具備することを特徴とする。 The magnetic sensor of the present invention has a meander shape having a sensitivity axis in a specific direction, and has a magnetoresistive effect having 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. And a pair of soft magnetic films arranged so as to sandwich the magnetoresistive element in a plan view.
　この構成によれば、特定の方向の外部磁界に対してはヨーク効果を発揮し、特定の方向と異なる方向の外部磁界に対してはシールド効果を発揮する。これにより、磁束発生源（磁石）との間の間隔（Ｇａｐ）が広くても磁気検知することができる。 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.
　本発明の磁気センサは、第１の方向に感度軸を持つミアンダ形状を有し、外部磁界に対して磁化変動する一対のフリー磁性層で非磁性層を挟持してなる積層構造を有する第１磁気抵抗効果素子、及び平面視において前記第１磁気抵抗効果素子を挟持するように配置された一対の軟磁性膜で構成された第１磁気検知素子と、前記第１の方向と異なる第２の方向に感度軸を持つミアンダ形状を有し、外部磁界に対して磁化変動する一対のフリー磁性層で非磁性層を挟持してなる積層構造を有する第２磁気抵抗効果素子、及び平面視において前記第２磁気抵抗効果素子を挟持するように配置された一対の軟磁性膜で構成された第２磁気検知素子と、が同一基板上に設けられており、ブリッジ回路を構成することを特徴とする。 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. .
　この構成によれば、特定の方向の外部磁界に対してはヨーク効果を発揮し、特定の方向と異なる方向の外部磁界に対してはシールド効果を発揮する。これにより、磁束発生源（磁石）との間の間隔（Ｇａｐ）が広くても磁気検知することができる。また、この構成によれば、感度軸方向が異なる磁気検知素子（第１磁気検知素子、第２磁気検知素子）を配置するので、異なる方向の外部磁界が混在する環境において微弱な外部磁界でも個々の感度軸方向の外部磁界を感度良く磁気検知することが可能となる。これにより、複雑な形状の磁束発生源（磁石）の磁気検知を正確に行うことができる。 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.
　本発明の磁気センサにおいては、前記第１の方向と前記第２の方向とが直交することが好ましい。 In the magnetic sensor of the present invention, it is preferable that the first direction and the second direction are orthogonal to each other.
　本発明の磁気センサにおいては、前記磁気抵抗効果素子の幅が、２μｍ～１０μｍであることが好ましい。 In the magnetic sensor of the present invention, it is preferable that the magnetoresistive element has a width of 2 μm to 10 μm.
　本発明の磁気センサにおいては、前記軟磁性膜の幅が、５０μｍ～１５０μｍであることが好ましい。 In the magnetic sensor of the present invention, the soft magnetic film preferably has a width of 50 μm to 150 μm.
　本発明の磁気センサにおいては、前記軟磁性膜を構成する材料が、ＣｏＺｒＮｂ、ＮｉＦｅ、Ｃｏ合金、及びＮｉ，Ｆｅを含む合金からなる群より選ばれたものであることが好ましい。 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.
　本発明の磁気センサにおいては、回転中心に対して回転可能である磁束発生源から間隔をおいて配置され、前記回転中心についての回転方向及び半径方向が前記第１の方向及び前記第２の方向であることが好ましい。この場合において、前記間隔が７ｍｍ以上であることが好ましい。 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.
　本発明の磁気センサは、特定の方向に感度軸を持つミアンダ形状を有し、外部磁界に対して磁化変動する一対のフリー磁性層で非磁性層を挟持してなる積層構造を有する磁気抵抗効果素子と、平面視において前記磁気抵抗効果素子を挟持するように配置された一対の軟磁性膜と、で構成された磁気検知素子を具備するので、磁束発生源（磁石）との間の間隔（Ｇａｐ）が広くても磁気検知することができる。 The magnetic sensor of the present invention has a meander shape having a sensitivity axis in a specific direction, and has a magnetoresistive effect having 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. Since it includes a magnetic sensing element composed of an element and a pair of soft magnetic films arranged so as to sandwich the magnetoresistive effect element in plan view, the distance between the magnetic flux generating source (magnet) ( Magnetic detection is possible even if Gap) is wide.
　本発明の磁気センサは、第１の方向に感度軸を持つミアンダ形状を有し、外部磁界に対して磁化変動する一対のフリー磁性層で非磁性層を挟持してなる積層構造を有する第１磁気抵抗効果素子、及び平面視において前記第１磁気抵抗効果素子を挟持するように配置された一対の軟磁性膜で構成された第１磁気検知素子と、前記第１の方向と異なる第２の方向に感度軸を持つミアンダ形状を有し、外部磁界に対して磁化変動する一対のフリー磁性層で非磁性層を挟持してなる積層構造を有する第２磁気抵抗効果素子、及び平面視において前記第２磁気抵抗効果素子を挟持するように配置された一対の軟磁性膜で構成された第２磁気検知素子と、が同一基板上に設けられており、ブリッジ回路を構成するので、磁束発生源（磁石）との間の間隔（Ｇａｐ）が広くても磁気検知することができる。 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 Gap,) wide can be magnetically detected.
本発明の実施の形態に係る磁気センサを示す図である。It is a figure which shows the magnetic sensor which concerns on embodiment of this invention. 本発明の実施の形態に係る磁気センサにおける磁気抵抗効果素子を説明するための図である。It is a figure for demonstrating the magnetoresistive effect element in the magnetic sensor which concerns on embodiment of this invention. 本発明の実施の形態１に係る磁気センサと磁束発生源（磁石）との間の間隔（Ｇａｐ）を説明するための図である。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). 本発明の実施の形態に係る磁気センサにおける回路を説明するための図である。It is a figure for demonstrating the circuit in the magnetic sensor which concerns on embodiment of this invention. （ａ），（ｂ）は、本発明の実施の形態に係る磁気抵抗効果素子の磁場－抵抗値特性を示す図である。(A), (b) is a figure which shows the magnetic field-resistance value characteristic of the magnetoresistive effect element based on Embodiment of this invention. 本発明の構成を有しない一つの磁気検出素子による磁気検知出力を示す図である。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）は、本発明の実施の形態１に係る磁気センサによるθ成分を検知した際の磁気検知出力を示す図であり、（ｂ）は、本発明の実施の形態１に係る磁気センサによるＲ成分を検知した際の磁気検知出力を示す図である。(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）は、本発明の実施の形態１に係る磁気センサにおいて、θ成分検知素子とＲ成分検知素子の中点電圧の出力を示す図であり、（ｂ）は、本発明の実施の形態１に係る磁気センサの磁気検知出力を示す図である。(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）は、本発明の実施の形態１に係る磁気センサについての効果を説明するための図であり、（ｂ）は、本発明の実施の形態２に係る磁気センサについての効果を説明するための図である。(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. 本発明の実施の形態２に係る磁気センサと磁束発生源（磁石）との間の間隔（Ｇａｐ）を説明するための図である。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). 本発明の構成を有しない一つの磁気検出素子による磁気検知出力を示す図である。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）は、本発明の実施の形態２に係る磁気センサによるθ成分を検知した際の磁気検知出力を示す図であり、（ｂ）は、本発明の実施の形態２に係る磁気センサによるＲ成分を検知した際の磁気検知出力を示す図である。(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）は、本発明の実施の形態２に係る磁気センサにおいて、θ成分検知素子とＲ成分検知素子の中点電圧の出力を示す図であり、（ｂ）は、本発明の実施の形態２に係る磁気センサの磁気検知出力を示す図である。(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. 本発明の実施の形態に係る磁気センサに用いる磁気抵抗効果素子を示す図である。It is a figure which shows the magnetoresistive effect element used for the magnetic sensor which concerns on embodiment of this invention. 磁気抵抗効果素子のパターン幅と検知磁界シフト量との間の関係を示す図である。It is a figure which shows the relationship between the pattern width of a magnetoresistive effect element, and a detection magnetic field shift amount. （ａ）は、軟磁性膜のパターン幅とセンサ検知外部磁束密度との間の関係を示す図であり、（ｂ）は、軟磁性膜のパターン幅と磁束密度増幅率との間の関係を示す図である。(A) is a figure which shows the relationship between the pattern width of a soft magnetic film, and a sensor detection external magnetic flux density, (b) shows the relationship between the pattern width of a soft magnetic film and magnetic flux density gain. FIG.
　以下、本発明の実施の形態について、添付図面を参照して詳細に説明する。
　図１は、本発明の実施の形態に係る磁気センサを示す平面図である。図２は、本発明の実施の形態に係る磁気センサにおける磁気抵抗効果素子を説明するための図である。 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.
　図１に示すように、基板１上（同一基板上）には、磁気検出素子である第１素子２と、磁気検出素子である第２素子３とが設けられている。第１素子２は、外部磁界の印加により抵抗値が変化する磁気抵抗効果素子２１と、平面視において磁気抵抗効果素子２１を挟持するように配置された一対の軟磁性膜２２とから構成されている。また、第２素子３は、外部磁界の印加により抵抗値が変化する磁気抵抗効果素子３１と、平面視において磁気抵抗効果素子３１を挟持するように配置された一対の軟磁性膜３２とから構成されている。基板１には、通常のプリント配線板に用いられる基板を用いることができる。また、図中の参照符号４は電極パッドを示す。 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.
　磁気抵抗効果素子２１，３１は、それぞれ特定の方向に感度軸を持つミアンダ形状を有している。磁気抵抗効果素子２１は、図１に示す矢印Ｘ方向に感度軸を持つミアンダ形状を有する。すなわち、図２に示すように、磁気抵抗効果素子２１は、略平行して形成された直線部２１ａと、直線部２１ａ同士を連接する連接部２１ｂとを有する。この直線部２１ａの延在方向に対して直交する方向（矢印Ｘ方向）が感度軸方向である。また、磁気抵抗効果素子３１は、図１に示す矢印Ｙ方向に感度軸を持つミアンダ形状を有する。同様に、磁気抵抗効果素子３１は、略平行して形成された直線部と、直線部同士を連接する連接部とを有する。この直線部の延在方向に対して直交する方向（図２における矢印Ｙ方向）が感度軸方向である。なお、図１においては、磁気抵抗効果素子２１の感度軸方向（矢印Ｘ方向）と磁気抵抗効果素子３１の感度軸方向（矢印Ｙ方向）とが直交している。 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.
　ここで、本発明者らは、磁気抵抗効果素子２１，３１のパターン幅（Ｄ１）と検知磁界シフト量との間の関係を調べた。その結果、感度軸方向の磁場に対しては、素子パターン幅が相対的に大きいほど感度が良く、比較的小さい磁場でセンサが動作することが分かった。このような観点から、磁気抵抗効果素子の２１，３１の幅（素子パターン幅）は、２μｍ～１０μｍであることが好ましい。 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 this point of view, the width (element pattern width) of the magnetoresistive elements 21 and 31 is preferably 2 μm to 10 μm.
　また、磁気抵抗効果素子２１，３１のパターン幅（Ｄ１）と検知磁界シフト量との間の関係を調べるため、磁気抵抗効果素子のパターン幅（Ｄ１）を２μｍから２０μｍまで変え、そのときの検知磁界シフト量（Ｏｅ）を磁界－抵抗変化特性（Ｒ－Ｈ特性）により調べた。その結果を図１５に示す。図１５から分かるように、感度軸方向に直交する方向の磁場に対しては、素子パターン幅により感度が変わらない（■印）。すなわち、感度軸方向に直交する方向の磁場に対しては、素子パターン幅に拘わらず、比較的小さい磁場でセンサが動作する。一方、感度軸方向の磁場に対しては、素子パターン幅により感度が変わり（◆印）、素子パターン幅が小さくなると、感度が低下する。すなわち、感度軸方向の磁場に対しては、素子パターン幅が相対的に大きいほど感度が良く、比較的小さい磁場でセンサが動作する。このような観点から、磁気抵抗効果素子の２１，３１の幅（素子パターン幅）は、Ｘ方向とＹ方向の検知磁界差が発生する１０μｍ以下の幅が好ましい。特に、磁気抵抗効果素子の２１，３１の幅（素子パターン幅）は、２μｍ～１０μｍであることが好ましい。 Further, in order to investigate the relationship between the pattern width (D 1 ) of the magnetoresistive effect elements 21 and 31 and the detected magnetic field shift amount, the pattern width (D 1 ) of the magnetoresistive effect element is changed from 2 μm to 20 μm. The detected magnetic field shift amount (Oe) was examined by the magnetic field-resistance change characteristic (RH characteristic). The result is shown in FIG. As can be seen from FIG. 15, for the magnetic field in the direction orthogonal to the sensitivity axis direction, the sensitivity does not change depending on the element pattern width (■ mark). That is, for a magnetic field in a direction orthogonal to the sensitivity axis direction, the sensor operates with a relatively small magnetic field regardless of the element pattern width. On the other hand, for the magnetic field in the sensitivity axis direction, the sensitivity changes depending on the element pattern width (♦ mark), and the sensitivity decreases as the element pattern width decreases. That is, with respect to the magnetic field in the sensitivity axis direction, the sensitivity is better as the element pattern width is relatively larger, and the sensor operates with a relatively smaller magnetic field. From such a viewpoint, the width (element pattern width) of the magnetoresistive effect elements 21 and 31 is preferably a width of 10 μm or less in which a difference in detection magnetic field between the X direction and the Y direction occurs. In particular, the width (element pattern width) of the magnetoresistive effect elements 21 and 31 is preferably 2 μm to 10 μm.
　磁気抵抗効果素子２１，３１としては、ＴＭＲ素子（トンネル型磁気抵抗効果素子）、ＧＭＲ素子（巨大磁気抵抗効果素子）などを用いることができる。例えば、ＧＭＲ素子として、それぞれ外部磁界に対して磁化変動する一対のフリー磁性層で非磁性層を挟持してなる多層膜積層構造を有するＧＭＲ素子やＴＭＲ素子を用いることができる。すなわち、図１４に示すように、磁気抵抗効果素子２１，３１は、フリー磁性層／非磁性層／フリー磁性層の積層構造を有する。ここで、非磁性層を構成する材料としては、Ｃｕ、などが挙げられる。また、フリー磁性層を構成する材料としては、Ｎｉ－Ｆｅ合金などの軟磁性材料が挙げられる。なお、磁気抵抗効果素子２１，３１は、フリー磁性層／非磁性層／フリー磁性層の積層構造を少なくとも有していれば良く、他の層が設けられていても良い。また、フリー磁性層の厚さとしては、１ｎｍ～６ｎｍであることが好ましく、非磁性層の厚さとしては、１．８ｎｍ～２．６ｎｍであることが好ましい。 As the magnetoresistive effect elements 21 and 31, a TMR element (tunnel type 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. Examples of the material constituting the free magnetic layer include soft magnetic materials such as Ni—Fe alloys. 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. In addition, 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.
　ここで使用する磁気抵抗効果素子２１，３１は、装置内のセンサ設置の関係から特定の方向からの磁界を検知する必要がなく、極性も判別する必要がないので、固定磁性層（ピンド層）が不要であり、フリー磁性層／非磁性層／フリー磁性層の積層構造を採用している。このため、製造工程において、加熱下で磁場を印加して固定磁性層（ピンド層）を形成する必要がない。これにより、基板上にフォトリソグラフィ及びエッチングにより磁気抵抗効果素子をパターニングすることができ、製造工程を簡略化することができる。また、フォトリソグラフィでパターニングすることができるので、微細な領域にも磁気抵抗効果素子をパターニングすることができる。 Since the magnetoresistive effect elements 21 and 31 used here do not need to detect a magnetic field from a specific direction because of the sensor installation 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.
　例えば、フリー磁性層や非磁性層を形成する場合、基板上にフリー磁性層材料を被着し、その上にレジスト層を形成し、フォトリソグラフィ及びエッチングでパターニングしてフリー磁性層を形成した後にレジスト層を除去する。 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.
　磁気抵抗効果素子２１，３１を挟持するように配置された一対の軟磁性膜２２，３２は、特定の方向の外部磁界を増幅すると共に、特定の方向と異なる方向の外部磁界を減衰させる。すなわち、軟磁性膜２２，３２は、特定の方向の外部磁界に対してはヨーク効果を発揮し、特定の方向と異なる方向（特定の方向と直交する方向）の外部磁界に対してはシールド効果を発揮する。軟磁性膜２２は、感度軸方向（矢印Ｘ方向）の外部磁界を増幅すると共に、感度軸方向に直交する方向（矢印Ｙ方向）の外部磁界をシールドする。一方、軟磁性膜３２は、感度軸方向（矢印Ｙ方向）の外部磁界を増幅すると共に、感度軸方向に直交する方向（矢印Ｘ方向）の外部磁界をシールドする。なお、軟磁性膜を構成する材料が、ＣｏＺｒＮｂ、ＮｉＦｅ、Ｃｏ合金、及びＮｉ，Ｆｅを含む合金からなる群より選ばれたものであることが好ましい。 The pair of soft magnetic films 22 and 32 disposed so as to sandwich the magnetoresistive effect elements 21 and 31 amplify an external magnetic field in a specific direction and attenuate 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.
　ここで、軟磁性膜２２，３２のパターン幅（Ｄ２，Ｄ３）とセンサ検知外部磁束密度（Ｇ）との間の関係を調べた。すなわち、厚さ０．５μｍの軟磁性膜（ＣｏＺｒＮｂ膜）のパターン幅（Ｄ２，Ｄ３）を０（なし）、５０μｍ、１００μｍ、１５０μｍとし、そのときのセンサ検知外部磁束密度（Ｇ）を磁界－抵抗変化特性（Ｒ－Ｈ特性）により調べた。その結果を図１６（ａ）に示す。図１６（ａ）から分かるように、軟磁性膜のパターン幅が広くなるほどセンサの検知磁界が小さくなる（センサの高感度化）。このため、センサの高感度化の観点からは、軟磁性膜２２，３２のパターン幅（Ｄ２，Ｄ３）は、５０μｍ以上、特に５０μｍ～１５０μｍであることが好ましい。 Here, the relationship between the pattern widths (D 2 , D 3 ) of the soft magnetic films 22 and 32 and the sensor detected external magnetic flux density (G) was examined. That is, the pattern width (D 2 , D 3 ) of a 0.5 μm thick soft magnetic film (CoZrNb film) is 0 (none), 50 μm, 100 μm, and 150 μm, and the sensor detected external magnetic flux density (G) at that time The magnetic field-resistance change characteristic (RH characteristic) was examined. The result is shown in FIG. As can be seen from FIG. 16A, the detection magnetic field of the sensor decreases as the pattern width of the soft magnetic film increases (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 or more, particularly 50 μm to 150 μm.
　また、軟磁性膜２２，３２のパターン幅（Ｄ２，Ｄ３）と磁束密度増幅率との間の関係を調べた。すなわち、厚さ０．５μｍの軟磁性膜（ＣｏＺｒＮｂ膜）のパターン幅（Ｄ２，Ｄ３）を０（Reference）、５０μｍ、１００μｍ、１５０μｍとし、そのときの磁束密度の増幅率（Reference基準）を磁界－抵抗変化特性（Ｒ－Ｈ特性）により調べた。その結果を図１６（ｂ）に示す。図１６（ｂ）から分かるように、軟磁性膜のパターン幅が広くなるほど磁束密度の増幅率が高くなる（幅５０μｍで２倍、幅１５０μｍで４倍）。このため、磁束密度の増幅率の観点からは、軟磁性膜２２，３２のパターン幅（Ｄ２，Ｄ３）は、５０μｍ以上とし、各磁気検知システムで必要なセンサ感度に合わせて設定することが好ましい。 Further, the relationship between the pattern width (D 2 , D 3 ) of the soft magnetic films 22 and 32 and the magnetic flux density gain was examined. That is, the pattern width (D 2 , D 3 ) of a 0.5 μm thick soft magnetic film (CoZrNb film) is set to 0 (Reference), 50 μm, 100 μm, and 150 μm, and the magnetic flux density amplification factor (Reference reference) at that time Were examined by magnetic field-resistance change characteristics (RH characteristics). The result is shown in FIG. As can be seen from FIG. 16B, the wider the pattern width of the soft magnetic film, the higher the amplification factor of the magnetic flux density (2 times when the width is 50 μm and 4 times when the width is 150 μm). 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 should be 50 μm or more and set according to the sensor sensitivity required for each magnetic detection system. Is preferred.
　図１６（ａ），（ｂ）の結果から、センサの高感度化の観点、磁束密度の増幅率の観点を考慮すると、軟磁性膜の幅は５０μｍ以上であることが好ましい。また、軟磁性膜の厚さは０．５μｍ以上であることが好ましい。 From the results shown in FIGS. 16A and 16B, the width of the soft magnetic film is preferably 50 μm or more in consideration of the high sensitivity of the sensor and the viewpoint of the magnetic flux density gain. The thickness of the soft magnetic film is preferably 0.5 μm or more.
　本発明の磁気センサの個々の磁気検知素子（第１素子２、第２素子３）においては、感度軸方向（第１素子２では矢印Ｘ方向、第２素子３では矢印Ｙ方向）の外部磁界が作用すると、一対のフリー磁性層の磁化方向が外部磁界方向に向く。これにより、両フリー磁性層の磁化方向が平行に近づいて抵抗値が低下する。この抵抗値の変化を出力とすることにより磁気検知することができる。このとき、磁気抵抗効果素子を挟持する一対の軟磁性膜により特定の方向の外部磁界を感度良く検知することができる。すなわち、一対の軟磁性膜が、特定の方向の外部磁界に対してヨーク効果を発揮し、特定の方向と異なる方向（ここでは特定の方向と直交する方向）の外部磁界に対してシールド効果を発揮する。これにより、磁束発生源（磁石）との間の間隔（Ｇａｐ）が広くても磁気検知することができる。 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.
　上記のように、本発明者らは、軟磁性膜２２，３２のパターン幅（Ｄ２，Ｄ３）とセンサ検知外部磁束密度（Ｇ）との間の関係を調べた。その結果、軟磁性膜のパターン幅が広くなるほどセンサの検知磁界が小さくなる（センサの高感度化）ことが分かった。このため、センサの高感度化の観点からは、軟磁性膜２２，３２のパターン幅（Ｄ２，Ｄ３）は、５０μｍ～１５０μｍであることが好ましい。 As described above, the present inventors examined the relationship between the pattern widths (D 2 , D 3 ) of the soft magnetic films 22 and 32 and the sensor detected external magnetic flux density (G). 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). Therefore, 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.
　また、本発明者らは、軟磁性膜２２，３２のパターン幅（Ｄ２，Ｄ３）と磁束密度増幅率との間の関係を調べた。その結果、軟磁性膜のパターン幅が広くなるほど磁束密度の増幅率が高くなることが分かった。このため、磁束密度の増幅率の観点からは、軟磁性膜２２，３２のパターン幅（Ｄ２，Ｄ３）は、５０μｍ以上とし、各磁気検知システムで必要とするセンサ感度に合わせた設定にすることができる。 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.
　上記の結果から、センサの高感度化の観点、磁束密度の増幅率の観点を考慮すると、軟磁性膜の幅は５０μｍ以上であることが好ましい。また、軟磁性膜の厚さは０．５μｍ以上であることが好ましい。 From the above results, it is preferable that the width of the soft magnetic film is 50 μm or more in consideration of the high sensitivity of the sensor and the viewpoint of the magnetic flux density gain. The thickness of the soft magnetic film is preferably 0.5 μm or more.
　本発明の磁気センサの個々の磁気検知素子（第１素子２、第２素子３）においては、感度軸方向（第１素子２では矢印Ｘ方向、第２素子３では矢印Ｙ方向）の外部磁界が作用すると、一対のフリー磁性層の磁化方向が外部磁界方向に向く。これにより、両フリー磁性層の磁化方向が平行に近づいて抵抗値が低下する。この抵抗値の変化を出力とすることにより磁気検知することができる。このとき、磁気抵抗効果素子を挟持する一対の軟磁性膜により特定の方向の外部磁界を感度良く検知することができる。すなわち、一対の軟磁性膜が、特定の方向の外部磁界に対してヨーク効果を発揮し、特定の方向と異なる方向（ここでは特定の方向と直交する方向）の外部磁界に対してシールド効果を発揮する。これにより、磁束発生源（磁石）との間の間隔（Ｇａｐ）が広くても磁気検知することができる。 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.
　（実施の形態１）
　本実施の形態においては、図３に示すような磁束発生源（磁石）４１の磁気検知について説明する。図３において、磁石４１と磁気センサ４２との間の距離（磁石表面とセンサ中心との間の距離）をＧａｐとする。磁石４１（４極磁極）は、歯車状（断面略十字状）であり、回転軸４１ａを中心に回転する。すなわち、磁気センサ４２は、回転中心（回転軸４１ａ）に対して回転可能である磁石４１からＧａｐをおいて配置される。 (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).
　また、磁気センサ４２は、図１に示す構成を有しており、磁石４１のそれぞれの先端部が近接した際に磁気を検知するようになっている。すなわち、磁気センサ４２は、回転する磁石４１を回転角９０°毎に磁気検知するようになっている。なお、図１における矢印Ｘ方向が回転中心についての磁石回転方向（θ方向）であり、図１における矢印Ｙ方向が回転中心についての磁石半径方向（Ｒ方向）である。したがって、磁気センサ４２における第１素子２は、θ方向の成分（θ成分）を増幅して、Ｒ方向の成分（Ｒ成分）を減衰させるθ成分検知素子であり、磁気センサ４２における第２素子３は、Ｒ方向の成分（Ｒ成分）を増幅して、θ方向の成分（θ成分）を減衰させるＲ成分検知素子である。 Further, the magnetic sensor 42 has the configuration shown in FIG. 1, and detects the magnetism when the tip portions of the magnets 41 are close to 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).
　また、磁気センサ４２において、第１素子２と第２素子３とは、図４に示すように電気的に接続されており、ブリッジ回路を構成している。そして、磁気センサ４２の出力は、図４に示すように、Ｒ成分検知素子とθ成分検知素子の中点電位としている。このような回路とすることにより、図３に示す４つの歯を持つ磁石４１に対して回転角９０°毎に磁気検知することができる。 Further, 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 °.
　ここでは、図３に示す磁石４１と磁気センサ４２との間の距離をそれぞれ５．１ｍｍ、６．１ｍｍ、７．１ｍｍと変えたときの磁気センサ４２の出力を調べた。なお、磁気センサ４２の磁気抵抗効果素子としては、図５（ａ），（ｂ）に示す特性を持つものを用いた。すなわち、磁気センサ４２の磁気抵抗効果素子は、感度軸方向に直交する方向の磁場－抵抗値の関係が図５（ａ）に示す曲線であり、感度軸方向の磁場－抵抗値の特性曲線が図５（ｂ）に示す曲線である。 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).
　図６は、本発明の構成を有しない一つの磁気検知素子で磁石４１の磁気検知をした場合を示す図である。図６から分かるように、Ｒ成分とθ成分とが混在した状態である。このような出力では、特に、Ｇａｐが７．１ｍｍの場合には、４つの歯を正確に磁気検知することは難しい（周期的なパルスとして出力することができない）。 FIG. 6 is a diagram showing a case where magnetism of the magnet 41 is detected by one magnetic sensing 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).
　一方、本発明の磁気センサ４２を用いた場合においては、θ成分検知素子である第１素子２のみの出力は図７（ａ）に示すようになる。すなわち、θ成分が増幅され、Ｒ成分が減衰されている。また、Ｒ成分検知素子である第２素子３のみの出力は図７（ｂ）に示すようになる。すなわち、Ｒ成分が増幅され、θ成分が減衰されている。そして、θ成分検知素子とＲ成分検知素子の中点電位は、図８（ａ）に示すようになる。図８（ａ）では、Ｇａｐが５．１ｍｍのものとＧａｐが７．１ｍｍのものを示している。この中点電位をパルス出力とすると、図８（ｂ）に示すようになる。図８（ｂ）から分かるように、Ｇａｐが５．１ｍｍでもＧａｐが７．１ｍｍでも、４つの歯を正確に磁気検知することができた（周期的なパルスとして出力することができた）。 On the other hand, when the magnetic sensor 42 of the present invention is used, the output of only the first element 2 which 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.
　ここで、図３に示す磁石４１と、図１に示す構成の双極１出力である磁気センサ４２とを準備し、両者の間の距離（磁石表面とセンサ中心との間の距離：Ｇａｐ）を５．１ｍｍ、７．１ｍｍとしたときのセンサ出力パルスのデューティを調べた（実施例１）。その結果を図９（ａ）に示す。また、図１に示す構成の双極１出力である磁気センサ４２を用いて、Ｇａｐを５．１ｍｍ、７．１ｍｍとしたときのセンサ出力パルスのデューティを調べた（実施例２）。その結果を図９（ａ）に併記する。さらに、図１に示す構成の双極１出力であり、一対の軟磁性膜２２，３２を設けない磁気センサを用いて、Ｇａｐを５．１ｍｍ、５．５ｍｍ、６．０ｍｍ、６．１ｍｍ、７．１ｍｍとしたときのセンサ出力パルスのデューティを調べた（比較例１）。その結果を図９（ａ）に併記する。さらに、図１に示す構成の双極１出力であり、一対の軟磁性膜２２，３２を設けない磁気センサを用いて、Ｇａｐを５．１ｍｍ、５．５ｍｍ、５．８ｍｍ、６．１ｍｍとしたときのセンサ出力パルスのデューティを調べた（比較例２）。その結果を図９（ａ）に併記する。さらに、図１に示す構成の双極１出力であり、一対の軟磁性膜２２，３２を設けない磁気センサを用いて、Ｇａｐを５．１ｍｍ、５．５ｍｍ、６．１ｍｍとしたときのセンサ出力パルスのデューティを調べた（比較例３）。その結果を図９（ａ）に併記する。 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.
　図９（ａ）から分かるように、実施例１、実施例２の磁気センサを用いた場合においては、Ｇａｐが７．１ｍｍまで目標デューティ（５０％±２０％）を満足し、磁石４１の磁気検知が可能である（Ｇａｐ依存が軽微）。一方、比較例１～比較例３の磁気センサを用いた場合においては、Ｇａｐが６．１ｍｍで目標デューティ（５０％±２０％）を満足できなかった（Ｇａｐ依存が大）。 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).
　このように、本発明の磁気センサによれば、感度軸方向が異なる磁気検知素子（第１素子２、第２素子３）を配置するので、異なる方向の外部磁界が混在する環境において微弱な外部磁界でも個々の感度軸方向の外部磁界を感度良く磁気検知することが可能となる。これにより、磁石との間のＧａｐが広くても、図３に示すような複雑な形状の磁束発生源（磁石）の磁気検知を正確に行うことができる。 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.
　（実施の形態２）
　本実施の形態においては、図１０に示すような磁束発生源（磁石）４３の磁気検知について説明する。図１０において、磁石４３と磁気センサ４２との間の距離（磁石表面とセンサ中心との間の距離）をＧａｐとする。磁石４３（６極磁極）は、６つの突出部４３ａを持つリング状であり、回転軸（破線）を中心に回転する。すなわち、磁気センサ４２は、回転中心（破線）に対して回転可能である磁石４３からＧａｐをおいて配置される。 (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).
　また、磁気センサ４２は、図１に示す構成を有しており、磁石４３のそれぞれの先端部が近接した際に磁気を検知するようになっている。すなわち、磁気センサ４２は、回転する磁石４３を回転角６０°毎に磁気検知するようになっている。なお、図１における矢印Ｘ方向が回転中心についての磁石回転方向（θ方向）であり、図１における矢印Ｙ方向が回転中心についての磁石半径方向（Ｒ方向）である。したがって、磁気センサ４２における第１素子２は、θ方向の成分（θ成分）を増幅して、Ｒ方向の成分（Ｒ成分）を減衰させるθ成分検知素子であり、磁気センサ４２における第２素子３は、Ｒ方向の成分（Ｒ成分）を増幅して、θ方向の成分（θ成分）を減衰させるＲ成分検知素子である。 Further, the magnetic sensor 42 has the configuration shown in FIG. 1, and detects the magnetism when the tips 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).
　また、磁気センサ４２において、第１素子２と第２素子３とは、上記図４に示すように電気的に接続されており、ブリッジ回路を構成している。そして、磁気センサ４２の出力は、図４に示すように、Ｒ成分検知素子とθ成分検知素子の中点電位としている。このような回路とすることにより、図１０に示す６つの歯を持つ磁石４３に対して回転角６０°毎に磁気検知することができる。 Further, in the magnetic sensor 42, the first element 2 and the second element 3 are electrically connected as shown in FIG. 4 and constitute 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.
　ここでは、図１０に示す磁石４３と磁気センサ４２との間の距離をそれぞれ５．１ｍｍ、７．１ｍｍと変えたときの磁気センサ４２の出力を調べた。なお、磁気センサ４２の磁気抵抗効果素子としては、図５（ａ），（ｂ）に示す特性を持つものを用いた。すなわち、磁気センサ４２の磁気抵抗効果素子は、感度軸方向に直交する方向の磁場－抵抗値の関係が図５（ａ）に示す曲線であり、感度軸方向の磁場－抵抗値の特性曲線が図５（ｂ）に示す曲線である。 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).
　図１１は、本発明の構成を有しない一つの磁気検知素子で磁石４３の磁気検知をした場合を示す図である。図１１から分かるように、Ｒ成分とθ成分とが混在した状態である。このような出力では、特に、Ｇａｐが７．１ｍｍの場合には、６つの突出部を正確に磁気検知することは難しい（周期的なパルスとして出力することができない）。 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).
　一方、本発明の磁気センサ４２を用いた場合においては、θ成分検知素子である第１素子２のみの出力は図１２（ａ）に示すようになる。すなわち、θ成分が増幅され、Ｒ成分が減衰されている。また、Ｒ成分検知素子である第２素子３のみの出力は図１２（ｂ）に示すようになる。すなわち、Ｒ成分が増幅され、θ成分が減衰されている。そして、θ成分検知素子とＲ成分検知素子の中点電位は、図１３（ａ）に示すようになる。この中点電位をパルス出力とすると、図１３（ｂ）に示すようになる。図１３（ｂ）から分かるように、Ｇａｐが５．１ｍｍでもＧａｐが７．１ｍｍでも、６つの突出部を正確に磁気検知することができた（周期的なパルスとして出力することができた）。 On the other hand, when the magnetic sensor 42 of the present invention is used, the output of only the first element 2 which 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). .
　ここで、図１０に示す磁石４３と、図１に示す構成の双極１出力である磁気センサ４２とを準備し、両者の間の距離（磁石表面とセンサ中心との間の距離：Ｇａｐ）を５．１ｍｍ、７．１ｍｍとしたときのセンサ出力パルスのデューティを調べた（実施例３）。その結果を図９（ｂ）に示す。また、図１に示す構成の双極１出力である磁気センサを用いて、Ｇａｐを５．１ｍｍ、７．１ｍｍとしたときのセンサ出力パルスのデューティを調べた（実施例４）。その結果を図９（ｂ）に併記する。さらに、図１に示す構成の双極１出力であり、一対の軟磁性膜２２，３２を設けない磁気センサを用いて、Ｇａｐを５．１ｍｍ、５．５ｍｍ、６．０ｍｍ、７．１ｍｍとしたときのセンサ出力パルスのデューティを調べた（比較例４）。その結果を図９（ｂ）に併記する。さらに、図１に示す構成の双極１出力であり、一対の軟磁性膜２２，３２を設けない磁気センサを用いて、Ｇａｐを５．１ｍｍ、５．５ｍｍ、６．１ｍｍとしたときのセンサ出力パルスのデューティを調べた（比較例５）。その結果を図９（ｂ）に併記する。さらに、図１に示す構成の双極１出力であり、一対の軟磁性膜２２，３２を設けない磁気センサを用いて、Ｇａｐを５．１ｍｍ、５．５ｍｍ、６．１ｍｍとしたときのセンサ出力パルスのデューティを調べた（比較例６）。その結果を図９（ｂ）に併記する。 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.
　図９（ｂ）から分かるように、実施例３、実施例４の磁気センサを用いた場合においては、Ｇａｐが７．１ｍｍまで目標デューティ（５０％±２０％）を満足し、磁石４３の磁気検知が可能である（Ｇａｐ依存が軽微）。一方、比較例４～比較例６の磁気センサを用いた場合においては、Ｇａｐが６．１ｍｍで目標デューティ（５０％±２０％）を満足できなかった（Ｇａｐ依存が大）。 As can be seen from FIG. 9B, in the case where 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 magnetism of the magnet 43 is increased. 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).
　このように、本発明の磁気センサによれば、感度軸方向が異なる磁気検知素子（第１素子２、第２素子３）を配置するので、異なる方向の外部磁界が混在する環境において微弱な外部磁界でも個々の感度軸方向の外部磁界を感度良く磁気検知することが可能となる。これにより、磁石との間のＧａｐが広くても、図１０に示すような複雑な形状の磁束発生源（磁石）の磁気検知を正確に行うことができる。 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.
　本発明は上記実施の形態１，２に限定されず、種々変更して実施することができる。例えば、上記実施の形態１，２における材料、各素子の接続関係、厚さ、大きさ、製法などは適宜変更して実施することが可能である。その他、本発明は、本発明の範囲を逸脱しないで適宜変更して実施することができる。 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.
　本発明は、流量検知用の磁気センサに適用することが可能である。 The present invention can be applied to a magnetic sensor for detecting a flow rate.
　本出願は、２００９年１０月２７日出願の特願２００９－２４６８５０及び、２００９年１０月２７日出願の特願２００９－２４６８５１に基づく。この内容は、全てここに含めておく。 This application is based on Japanese Patent Application No. 2009-246850 filed on October 27, 2009 and Japanese Patent Application No. 2009-246851 filed on October 27, 2009. All this content is included here.

Claims (8)

  1. 　特定の方向に感度軸を持つミアンダ形状を有し、外部磁界に対して磁化変動する一対のフリー磁性層で非磁性層を挟持してなる積層構造を有する磁気抵抗効果素子と、平面視において前記磁気抵抗効果素子を挟持するように配置された一対の軟磁性膜と、で構成された磁気検知素子を具備することを特徴とする磁気センサ。 A magnetoresistive element having a meander shape having a sensitivity axis in a specific direction and having a laminated structure in which a nonmagnetic layer is sandwiched between a pair of free magnetic layers that change in magnetization with respect to an external magnetic field; A magnetic sensor comprising: a magnetic sensing element comprising a pair of soft magnetic films arranged so as to sandwich a magnetoresistive effect element.
  2. 　第１の方向に感度軸を持つミアンダ形状を有し、外部磁界に対して磁化変動する一対のフリー磁性層で非磁性層を挟持してなる積層構造を有する第１磁気抵抗効果素子、及び平面視において前記第１磁気抵抗効果素子を挟持するように配置された一対の軟磁性膜で構成された第１磁気検知素子と、前記第１の方向と異なる第２の方向に感度軸を持つミアンダ形状を有し、外部磁界に対して磁化変動する一対のフリー磁性層で非磁性層を挟持してなる積層構造を有する第２磁気抵抗効果素子、及び平面視において前記第２磁気抵抗効果素子を挟持するように配置された一対の軟磁性膜で構成された第２磁気検知素子と、が同一基板上に設けられており、ブリッジ回路を構成することを特徴とする磁気センサ。 A first magnetoresistive element having a meander shape having a sensitivity axis in a first direction and having 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, and a plane And a meander having a sensitivity axis in a second direction different from the first direction, and a first magnetic sensing element composed of a pair of soft magnetic films arranged to sandwich the first magnetoresistive element when viewed A second magnetoresistive element having a laminated structure in which a nonmagnetic layer is sandwiched between a pair of free magnetic layers having a shape and magnetization variation with respect to an external magnetic field, and the second magnetoresistive element in plan view A magnetic sensor comprising: a second magnetic sensing element including a pair of soft magnetic films arranged so as to be sandwiched between the second magnetic sensing element and the second magnetic sensing element; and a bridge circuit.
  3. 　前記第１の方向と前記第２の方向とが直交することを特徴とする請求項２記載の磁気センサ。 3. The magnetic sensor according to claim 2, wherein the first direction and the second direction are orthogonal to each other.
  4. 　前記磁気抵抗効果素子の幅が、２μｍ～１０μｍであることを特徴とする請求項１記載の磁気センサ。 2. The magnetic sensor according to claim 1, wherein the magnetoresistive element has a width of 2 μm to 10 μm.
  5. 　前記軟磁性膜の幅が、５０μｍ～１５０μｍであることを特徴とする請求項１記載の磁気センサ。 2. The magnetic sensor according to claim 1, wherein the width of the soft magnetic film is 50 μm to 150 μm.
  6. 　前記軟磁性膜を構成する材料が、ＣｏＺｒＮｂ、ＮｉＦｅ、Ｃｏ合金、及びＮｉ，Ｆｅを含む合金からなる群より選ばれたものであることを特徴とする請求項１記載の磁気センサ。 The magnetic sensor according to claim 1, wherein 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.
  7. 　前記磁気センサは、回転中心に対して回転可能である磁束発生源から間隔をおいて配置され、前記回転中心についての回転方向及び半径方向が前記第１の方向及び前記第２の方向であることを特徴とする請求項３記載の磁気センサ。 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 3.
  8. 　前記間隔が７ｍｍ以上であることを特徴とする請求項７記載の磁気センサ。 The magnetic sensor according to claim 7, wherein the interval is 7 mm or more.
PCT/JP2010/068981 2009-10-27 2010-10-26 Magnetic sensor WO2011052596A1 (en)

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JP2009-246850 2009-10-27
JP2009246851A JP5467210B2 (en) 2009-10-27 2009-10-27 Magnetic sensor
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JP2009-246851 2009-10-27

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004039869A (en) * 2002-07-03 2004-02-05 Hitachi Ltd Magnetic reluctance sensor, magnetic head, and magnetic recording equipment
JP2009025319A (en) * 2006-11-21 2009-02-05 Hitachi Metals Ltd Rotation angle detector and rotary machine
WO2009084435A1 (en) * 2007-12-28 2009-07-09 Alps Electric Co., Ltd. Magnetic sensor and magnetic sensor module

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004039869A (en) * 2002-07-03 2004-02-05 Hitachi Ltd Magnetic reluctance sensor, magnetic head, and magnetic recording equipment
JP2009025319A (en) * 2006-11-21 2009-02-05 Hitachi Metals Ltd Rotation angle detector and rotary machine
WO2009084435A1 (en) * 2007-12-28 2009-07-09 Alps Electric Co., Ltd. Magnetic sensor and magnetic sensor module

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