WO2016170885A1 - Dispositif de capteur magnétique - Google Patents

Dispositif de capteur magnétique Download PDF

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Publication number
WO2016170885A1
WO2016170885A1 PCT/JP2016/058775 JP2016058775W WO2016170885A1 WO 2016170885 A1 WO2016170885 A1 WO 2016170885A1 JP 2016058775 W JP2016058775 W JP 2016058775W WO 2016170885 A1 WO2016170885 A1 WO 2016170885A1
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WO
WIPO (PCT)
Prior art keywords
magnetic
magnet
magnetosensitive element
magnetosensitive
sensor device
Prior art date
Application number
PCT/JP2016/058775
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English (en)
Japanese (ja)
Inventor
百瀬　正吾
Original Assignee
日本電産サンキョー株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by 日本電産サンキョー株式会社 filed Critical 日本電産サンキョー株式会社
Priority to CN201680023051.3A priority Critical patent/CN108156821A/zh
Publication of WO2016170885A1 publication Critical patent/WO2016170885A1/fr

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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
    • G—PHYSICS
    • G07—CHECKING-DEVICES
    • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
    • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
    • G07D7/04—Testing magnetic properties of the materials thereof, e.g. by detection of magnetic imprint
    • 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
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/08—Methods or arrangements for sensing record carriers, e.g. for reading patterns by means detecting the change of an electrostatic or magnetic field, e.g. by detecting change of capacitance between electrodes
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/265—Structure or manufacture of a head with more than one gap for erasing, recording or reproducing on the same track

Definitions

  • the present invention relates to a magnetic sensor device for detecting a magnetic pattern.
  • a magnetic sensor device including a magnet that generates a bias magnetic field and a magnetosensitive element such as a magnetoresistive element is used.
  • the magnetosensitive element detects a change in the magnetic field when the magnetic pattern passes through the detection position of the magnetic sensor device, and outputs a signal corresponding to the change in its resistance value.
  • a magnetic sensor device is described in Patent Document 1.
  • the magnetic pattern is printed with a magnetic ink containing a hard material such as ferrite powder, or a magnetic ink containing a soft material (soft magnetic material) such as a soft magnetic stainless steel powder.
  • the magnetic pattern has a magnetic permeability, so that the magnetosensitive element detects a change in the magnetic field caused by the magnetic permeability.
  • the magnetosensitive element detects a change in the magnetic field due to the residual magnetic flux density, but the change in the magnetic field due to the residual magnetic flux density. Is detected by being superimposed on the change in the magnetic field due to the magnetic permeability, so that the signal component derived from the residual magnetic flux density cannot be separated. Therefore, it cannot be determined whether the magnetic pattern is printed with magnetic ink containing hard material or magnetic ink containing soft material.
  • an object of the present invention is to provide a magnetic sensor device capable of discriminating either a hard material or a soft material from a magnetic pattern applied to a medium.
  • the present invention provides a magnetic sensor device for detecting a magnetic pattern applied to a medium that moves relative to a moving surface by a magnetosensitive element, a magnet that applies a bias magnetic field to the medium, A downstream yoke disposed on the downstream side of the magnet in the moving direction of the medium, and as the magnetosensitive element, the magnet facing the downstream yoke in an orthogonal direction perpendicular to the moving surface, Comprises a first magnetosensitive element disposed at a first position that does not oppose, and a second magnetosensitive element disposed at a second position that opposes the magnet in the orthogonal direction.
  • the second magnetosensitive element is disposed at the second position facing the magnet to which the bias magnetic field is applied. Therefore, when the medium passes through the second position along the moving surface, the change in the magnetic field due to the magnetic permeability of the magnetic pattern can be detected by the second magnetosensitive element.
  • the first magnetosensitive element is disposed at a first position facing a yoke disposed downstream of the magnet to which the bias magnetic field is applied.
  • the first position is in a region separated from the region facing the magnet, the change in the direction of the magnetic field is small and the magnetic flux density is small when the medium passes through the second position along the moving surface.
  • the signal component output from the first magnetosensitive element arranged at the first position is substantially output from the magnetic permeability. Can be zero.
  • the first position is in a region away from the region facing the magnet on the downstream side of the magnet in the moving direction of the medium, the first magnetosensitive element arranged in the first position is caused by the residual magnetic flux density of the magnetic pattern. The change of the magnetic field can be detected. Therefore, based on the signal output from the first magnetosensitive element, it is possible to determine whether the magnetic pattern applied to the medium is a hard material or a soft material.
  • the first position and the second position may be in the bias magnetic field from the magnet to the downstream yoke via the moving surface.
  • the first magnetosensitive element has a magnetosensitive direction in the moving direction. In this way, the first magnetosensitive element detects the moving direction component of the change in the direction of the magnetic field. Thereby, it becomes easy to make the output of the signal component derived from the magnetic permeability substantially zero for the signal output from the first magnetosensitive element.
  • an MR element can be used as the magnetosensitive element.
  • the present invention it is desirable to have an upstream yoke disposed on the upstream side of the magnet in the moving direction. If it does in this way, it can control that the magnetic field which a magnet generates by downstream Yuku and an upstream yoke spreads more than necessary. Therefore, it is possible to prevent the magnetic sensing element from detecting a change in the magnetic field due to the movement of the magnetic material different from the medium. In this way, it is possible to prevent or suppress the magnetosensitive element from being affected by the magnetic field outside the apparatus.
  • the end surface on the moving surface side in the magnet, the end surface on the moving surface side in the downstream yoke, and the end surface on the moving surface side in the upstream yoke are located on the same plane, It is desirable to extend parallel to the moving surface.
  • the magnetosensitive element includes a third magnetosensitive element disposed at a third position facing the upstream yoke in a direction orthogonal to the moving surface and not facing the magnet. be able to.
  • the third magnetosensitive element arranged at the third position. That is, when the relative movement direction of the medium with respect to the apparatus is reversed, the medium passes through the third position after passing through the position facing the magnet along the moving surface. Therefore, when a magnetic pattern made of a hard material is applied to the medium, the hard material is magnetized when the medium passes through the third position. Therefore, a change in the magnetic field due to the residual magnetic flux density of the magnetic pattern (hard material) can be detected by the third magnetosensitive element.
  • this invention has a 2nd magnet which applies a 2nd bias magnetic field to the said medium, and the said 2nd magnet shall be located in the downstream of the said downstream yoke in the said moving direction. .
  • the change of the magnetic field caused by the residual magnetic flux density of the magnetic pattern (hard material) is caused by the first magnetosensitive element arranged at the first position.
  • the medium passes through the first position after passing through the position facing the second magnet along the moving surface. Therefore, when a magnetic pattern made of a hard material is applied to the medium, the hard material is magnetized when the medium passes through the first position. Therefore, a change in the magnetic field due to the residual magnetic flux density of the magnetic pattern (hard material) can be detected by the first magnetosensitive element.
  • a plurality of the first magnetosensitive elements and the second magnetosensitive elements are respectively arranged in a direction along the moving surface so as to intersect the moving direction, and the magnet includes a plurality of the second magnetosensitive elements. It is desirable to extend in the arrangement direction of the magnetosensitive elements and to face each second magnetosensitive element. In this way, the magnetic pattern can be detected in a wide range extending in the width direction of the medium. Further, since one long magnet extending in the arrangement direction of the first magnetosensitive elements is used as the magnet, a plurality of magnets corresponding to the first magnetosensitive elements are arranged in the arrangement direction of the first magnetosensitive elements.
  • the downstream yoke extends along the magnet and opposes each first magnetosensitive element. Since the magnetic field generated by the magnet is guided to the downstream yoke, in this way, the magnetic field of the magnet formed so as to pass through the transport surface is made uniform along the magnetic sensing direction of each magnetic sensing element. be able to. As a result, it is possible to prevent or suppress the occurrence of a difference in the output from the first magnetosensitive element due to the position of the first magnetosensitive element in the arrangement direction.
  • the first magnetic sensitive element and the second magnetic sensitive element in the width direction of the transport path orthogonal to the moving direction of the medium are such that the distance from the end of the magnet is the moving direction of the medium of the magnet and It is desirable that they are separated by 1/2 or more of the height dimension orthogonal to the width direction of the transport path.
  • the magnetic pattern applied to the medium is a hard material or a soft material based on a signal output from the first magnetosensitive element.
  • FIG. 1 is an explanatory view schematically showing a main part configuration of a magnetic sensor device to which the present invention is applied.
  • the magnetic sensor device 20 of the present invention detects the magnetic pattern M applied to the sheet-like medium 3 such as banknotes conveyed along the conveyance path 21 (conveying surface 2) by the magnetic sensitive elements 11 and 12.
  • the magnetic pattern M detected by the magnetic sensor device 20 includes one printed with magnetic ink containing a hard material and one printed with magnetic ink containing a soft material.
  • the hard material is a magnetic material that is easily magnetized when applied with a magnetic field from the outside, such as a magnetic material used in a magnet, having a large hysteresis and a high residual magnetic flux density.
  • the soft material is a magnetic material that has a small hysteresis, a low residual magnetic flux density, and is not easily magnetized, like a core material of a motor or a magnetic head.
  • the magnetic sensor device 20 includes a sensor unit 1 and a transport mechanism 22 that transports the medium 3 along a transport path 21 that passes through a detection position by the sensor unit 1.
  • the transport mechanism 22 includes a transport roller 23 and a transport motor 24 serving as a drive source for the transport roller 23.
  • the sensor unit 1 extends in the width direction Y of the transport path 21 orthogonal to the transport direction X1 of the medium 3.
  • the conveyance roller 23 is disposed to face the sensor unit 1 in the orthogonal direction Z orthogonal to the conveyance surface 2 that is a moving surface.
  • the sensor unit 1 is accommodated in a nonmagnetic case 25.
  • the facing surface facing the transport roller 23 defines the detection position of the magnetic pattern M by the magnetic sensor device 20 and constitutes a part of the transport surface 2 in the transport path 21.
  • the sensor unit 1 includes a plurality of MR substrates 26 on which the first magnetosensitive element 11 and the second magnetosensitive element 12 are formed.
  • the MR substrate 26 is arranged in the width direction Y along the transport surface 2. Therefore, the sensor unit 1 includes a plurality of first magnetosensitive elements 11 arranged in the width direction Y and a plurality of second magnetosensitive elements 12 arranged in the width direction Y.
  • the second magnetosensitive element 12 is disposed upstream of the first magnetosensitive element 11 in the transport direction X1.
  • the sensor unit 1 includes a permanent magnet 5, a downstream yoke 6 disposed on the downstream side of the permanent magnet 5 in the conveyance direction X ⁇ b> 1 of the medium 3, and an upstream yoke 7 disposed on the upstream side of the permanent magnet 5.
  • the permanent magnet 5 applies a bias magnetic field 4 to the medium 3, the first magnetosensitive element 11 and the second magnetosensitive element 12 conveyed on the conveyance surface 2.
  • the transport surface 2 is disposed on the opposite side (orthogonal direction Z side) of the permanent magnet 5, the downstream yoke 6 and the upstream yoke 7 with the first and second magnetosensitive elements 11 and 12 interposed therebetween. .
  • the permanent magnet 5 is long and has a rectangular parallelepiped shape.
  • the permanent magnet 5 extends with a constant width in the width direction Y (the arrangement direction of the plurality of first magnetosensitive elements 11).
  • the permanent magnet 5 faces each second magnetosensitive element 12.
  • the downstream yoke 6 abuts against the downstream end surface of the permanent magnet 5 and extends along the permanent magnet 5 with a constant width in the width direction Y.
  • the downstream yoke 6 faces each first magnetosensitive element 11.
  • the upstream yoke 7 is in contact with the upstream end surface of the permanent magnet 5 and extends along the permanent magnet 5 with a constant width in the width direction Y.
  • the downstream yoke 6 and the upstream yoke 7 are each elongated and have a rectangular parallelepiped shape.
  • the dimensions in the width direction Y of the permanent magnet 5, the downstream yoke 6 and the upstream yoke 7 are the same.
  • the first magnetosensitive element 11 and the second magnetosensitive element 12 positioned at both end portions in the width direction Y are disposed at positions spaced from the end portion 5a of the permanent magnet 5 by a predetermined distance T or more.
  • the specified distance T is 1 ⁇ 2 of the height dimension L in the vertical direction of the permanent magnet 5.
  • FIG. 2 is an explanatory view of the arrangement of the permanent magnet 5 and the magnetic sensitive elements 11 and 12 in the sensor unit 1 of the magnetic sensor device 20 of the present invention.
  • 3A is a graph of the resistance value-magnetic flux density characteristic curve of the first magnetosensitive element 11
  • FIG. 3B is a graph of the resistance value-magnetic flux density characteristic curve of the second magnetosensitive element 12.
  • FIG. 2 contrary to FIG. 1, the permanent magnet 5 is shown above the magnetic sensing elements 11 and 12 toward the drawing, and the conveying surface 2 is shown below the magnetic sensing elements 11 and 12 toward the drawing.
  • the permanent magnet 5 is magnetized in a direction perpendicular to the transport surface 2.
  • the permanent magnet 5 has the N pole facing the transport surface 2 side.
  • the downstream yoke 6 contacts the permanent magnet 5 from the downstream side
  • the upstream yoke 7 contacts the permanent magnet 5 from the upstream side.
  • the end surface of the permanent magnet 5 on the side of the conveyance surface 2 and the end surface of the downstream yoke 6 and the upstream yoke 7 on the side of the conveyance surface 2 are located on the same plane and extend in parallel with the conveyance surface 2.
  • the first magnetosensitive element 11 and the second magnetosensitive element 12 are both magnetoresistive elements. More specifically, it is an anisotropic magnetoresistive element (AMR (Anisotropic-Magneto-Resistance)) having a magnetoresistive pattern made of a thin film ferromagnetic metal.
  • AMR Anasotropic-Magneto-Resistance
  • the resistance value decreases according to the strength of the magnetic field.
  • the magnetosensitive direction F of the first magnetosensitive element 11 and the second magnetosensitive element 12 is the conveyance direction X1, and the first magnetosensitive element 11 and the second magnetosensitive element 12 detect a change in the magnetic flux vector in the conveyance direction X1. .
  • the first magnetosensitive element 11 is disposed at a first position A that faces the downstream yoke 6 and does not face the permanent magnet 5 in the orthogonal direction Z perpendicular to the transport surface 2.
  • the second magnetosensitive element 12 is disposed at the second position B facing the permanent magnet 5 in the orthogonal direction Z.
  • the second position B is upstream of the first position A in the transport direction X1.
  • the first position A and the second position B are in the bias magnetic field 4 from the permanent magnet 5 to the downstream yoke 6 via the transport surface 2.
  • the distance between the end surface of the downstream yoke 6 on the transport surface 2 side and the first magnetosensitive element 11 is the same as the distance between the end surface of the permanent magnet 5 on the transport surface 2 side and the second magnetosensitive element 12. is there.
  • a bias magnetic field 4 (first magnetic flux vector Ha0) is applied so that the change in resistance value increases with respect to the change in magnetic flux density in the resistance value-magnetic flux density characteristics of the first magnetosensitive element 11. It is a position. In other words, at the first position A, when the first magnetosensitive element 11 is disposed, the resistance value R1 is plotted on the steep curve portion of the resistance value-magnetic flux density characteristic curve of FIG. It is a position.
  • a bias magnetic field 4 (second magnetic flux vector Hb0) is applied so that the change in resistance value increases with respect to the change in magnetic flux density in the resistance value-magnetic flux density characteristics of the second magnetosensitive element 12. It is a position. In other words, at the second position B, when the second magnetosensitive element 12 is arranged, the resistance value R2 is plotted in a curve portion having a steep slope in the resistance value-magnetic flux density characteristic curve of FIG. It is a position.
  • the first magnetic flux vector Ha0 at the first position A is inclined in the direction toward the downstream yoke 6 toward the downstream side.
  • the second magnetic flux vector Hb0 at the second position B is inclined in the direction away from the permanent magnet 5 toward the downstream side.
  • the inclination of the first magnetic flux vector Ha0 with respect to the orthogonal direction Z is larger than the inclination of the second magnetic flux vector Hb0 with respect to the orthogonal direction Z.
  • the first magnetosensitive element 11 and the second magnetosensitive element 12 a semiconductor magnetoresistive element, a Hall element, an MI element (Magneto-Impedance element), a fluxgate type magnetic sensor, or the like may be used. Further, the first magnetosensitive element 11 may be disposed on the opposite side of the downstream yoke 6 with the transport surface 2 interposed therebetween. Similarly, the second magnetosensitive element 12 may be disposed on the opposite side of the permanent magnet 5 with the transport surface 2 interposed therebetween. Furthermore, the 1st magnetosensitive element 11 and the 2nd magnetosensitive element 12 may be arrange
  • the second position B can be a position where at least a part of the second magnetosensitive element 12 faces the permanent magnet 5 in the orthogonal direction Z.
  • the distance between the end face of the downstream yoke 6 on the transport surface 2 side and the first magnetosensitive element 11 is the distance between the end face of the permanent magnet 5 on the transport surface 2 side and the second magnetosensitive element 12. It may be different.
  • the upstream yoke 7 may be omitted.
  • the permanent magnet may be arranged with the south pole facing the transport surface 2 side.
  • FIG. 4 is a schematic diagram showing the sensor unit 1 partially enlarged.
  • FIG. 5 is an explanatory diagram of changes in the magnetic flux vectors Ha 0 and Hb 0 when the magnetic pattern M moves on the transport surface 2.
  • FIG. 6 is an explanatory diagram of changes in the magnetic field when the magnetic pattern M including the hard material moves on the transport surface 2. 4 to 6, only the magnetic pattern M applied to the medium 3 is shown with the medium 3 omitted in order to easily show the changes in the magnetic flux vectors Ha0 and Hb0 and the change in the magnetic field.
  • the bias magnetic field 4 is caused by the magnetic permeability of the magnetic pattern M.
  • the direction of the magnetic flux changes so as to be absorbed by the magnetic pattern M.
  • the second magnetic flux vector Hb0 passing through the second position B where the second magnetosensitive element 12 is disposed changes its direction before and after the transport direction X.
  • the second magnetic flux vector Hb0 is inclined in the direction approaching the normal line (orthogonal direction Z) toward the magnetic pattern M (magnetic flux vector Hb1). As shown in FIG. 5 (b), it is inclined toward the downstream side of the first magnetic flux vector Hb0 (magnetic flux vector Hb2).
  • the magnetic flux density is large (the magnetic flux vector Hb0 is large). Accordingly, the component Hbf in the magnetic sensing direction F of the magnetic flux vector Hb0 detected by the second magnetic sensing element 12 changes greatly. Thereby, the resistance value of the second magnetosensitive element 12 varies within a relatively large range S2 shown in FIG. 3B, and a signal corresponding to the variation of the resistance value is output from the second magnetosensitive element 12. .
  • the direction of the first magnetic flux vector Ha0 passing through the first position A is also changed back and forth.
  • the magnetic flux density of the bias magnetic field 4 passing through the first position A is small (magnetic flux vector Ha0) as schematically shown in FIG. Is small).
  • the component Haf of the first magnetic flux vector Ha0 detected by the first magnetic sensing element 11 in the magnetic sensing direction F is the sensitivity of the first magnetic flux vector Ha0 detected by the second magnetic sensing element 12. It becomes smaller than the component Hbf in the magnetic direction F.
  • the resistance value of the second magnetosensitive element 12 changes only in a very small range S1 shown in FIG. 3, corresponding to the resistance value fluctuation.
  • the signal output from the second magnetosensitive element 12 is substantially zero.
  • the magnetic pattern M applied to the medium 3 passes through the downstream detection position D facing the first position A on the transport surface 2, the magnetic pattern M is an area facing the permanent magnet 5 (critical path). Range). Therefore, when the magnetic pattern M is made of a hard material, the magnetic pattern M is magnetized. Therefore, as shown in FIG. 6A, the magnetic pattern M generates a residual magnetic field 8. On the other hand, when the magnetic pattern M is made of a soft material, the magnetic pattern M is not magnetized. Therefore, no residual magnetic field is generated as shown in FIG.
  • the downstream side detection position D and the first position A are at positions deviating from the region facing the permanent magnet 5 (critical path range). Therefore, the first magnetosensitive element 11 detects a change in the magnetic field caused by the residual magnetic flux density of the magnetic pattern M when the magnetic pattern M is magnetized. Thereby, since the resistance value of the first magnetosensitive element 11 varies, a signal corresponding to the variation of the resistance value is output from the first magnetosensitive element 11. On the other hand, when the magnetic pattern M is not magnetized, the first magnetosensitive element 11 does not detect a change in the magnetic field due to the residual magnetic flux density of the magnetic pattern M. Does not output a signal corresponding to a change in resistance value.
  • FIG. 7A is a graph showing an output example from the first magnetosensitive element 11 and an output example from the second magnetosensitive element 12 when the sensor unit 1 detects a magnetic pattern M made of a hard material.
  • 7 (b) is a graph showing an output example from the first magnetosensitive element 11 and an output example from the second magnetosensitive element 12 when the sensor unit 1 detects a magnetic pattern M made of a soft material.
  • FIG. 7A when the magnetic pattern M is made of a hard material, signals are output from both the second magnetic sensing element 12 and the first magnetic sensing element 11.
  • FIG. 7B when the magnetic pattern M is made of a soft material, a signal is output from the second magnetosensitive element 12, but a signal is output from the first magnetosensitive element 11.
  • a signal is output from the second magnetosensitive element 12
  • a signal is output from the first magnetosensitive element 11.
  • the magnetic sensor device 20 can determine whether the magnetic pattern M is formed of a hard material or a soft material based on a signal from the first magnetosensitive element 11.
  • the magnetic information of the magnetic pattern M can be acquired based on the signal from the first magnetosensitive element 11 and the signal from the second magnetosensitive element 12.
  • the magnetic pattern M is made of a soft material
  • the magnetic information of the magnetic pattern M can be acquired based on the signal from the second magnetosensitive element 12.
  • the magnetic sensor device 20 since the plurality of first magnetosensitive elements 11 and the plurality of second magnetosensitive elements 12 arranged in the width direction Y of the conveyance path 21 (conveyance surface 2) are provided, The magnetic pattern M applied to the medium 3 can be detected in a wide range extending in the width direction.
  • the first magnetic sensing element 11 detects a component of the magnetic flux vector in the conveyance direction X1 (magnetic sensing direction F). Therefore, if the first magnetosensitive element 11 is disposed in a magnetic field portion including a magnetic flux vector directed in the transport direction X1 in the bias magnetic field 4, the first magnetosensitive element 11 can detect a change in the magnetic flux vector. On the other hand, when the first magnetosensitive element 11 is disposed in the magnetic field portion including the magnetic flux vector inclined with respect to the transport direction X1 in the bias magnetic field 4, the first magnetosensitive element 11 is along the transport direction X1 of the magnetic flux vector. Only detected components are detected.
  • the bias magnetic field 4 (magnetic flux vector) passing through the first magnetosensitive element 11 is directed in the magnetosensitive direction F.
  • Different signals are output from the first magnetosensitive element 11 when the bias magnetic field 4 (magnetic flux vector) passing through the first magnetosensitive element 11 is inclined. Therefore, if the bias magnetic field 4 (magnetic flux vector) is not uniform in the magnetic sensing direction F, there is a problem that the detection accuracy of the magnetic information of the magnetic pattern M is lowered.
  • the downstream yoke 6 and the upstream yoke 7 are arranged on both sides of the long permanent magnet 5 between the permanent magnet 5 and the downstream in the transport direction X1.
  • the side yoke 6 and the upstream yoke 7 extend in parallel to a direction orthogonal to the transport direction X1. Accordingly, the bias magnetic field 4 (magnetic flux vector) formed by the permanent magnet 5 so as to pass through the transport surface 2 is guided to the downstream yoke 6 and the upstream yoke 7, and the first magnetosensitive element 11 and the second magnetosensitive element. It becomes uniform in the transport direction X1, which is the magnetic sensing direction F of the element 12.
  • the bias magnetic field 4 (magnetic flux vector) passing through the first magnetosensitive element 11 does not tilt with respect to the transport direction X1 regardless of the position in the width direction Y, so that the magnetic information of the magnetic pattern M can be accurately obtained. It can be detected.
  • the magnetic sensing elements 11 and 12 arranged at the end in the width direction Y are separated from the end of the permanent magnet 5 by a distance T of 1/2 or more of the height L in the vertical direction of the permanent magnet 5. ing. Therefore, the bias magnetic field 4 (magnetic flux vector) passing through the magnetosensitive elements 11 and 12 disposed at the end in the width direction Y can also be oriented in the magnetosensitive direction F.
  • the bias magnetic field 4 generated by the permanent magnet 5 is unnecessarily spread by the downstream side YUK and the upstream side yoke 7 arranged on both sides of the permanent magnet 5. Accordingly, it is possible to prevent the first magnetic sensing element 11 and the second magnetic sensing element 12 from detecting a change in the magnetic field caused by the movement of a magnetic material different from the magnetic pattern M of the medium 3. Further, by providing the downstream side YUK and the upstream side yoke 7 disposed on both sides of the permanent magnet 5, the first magnetic sensing element 11 and the second magnetic sensing element 12 are affected by the magnetic field outside the sensor unit 1. It can be prevented or suppressed.
  • FIG. 8A is an explanatory diagram of the sensor unit of the first modification
  • FIG. 8B is an explanatory diagram of the sensor unit of the second modification.
  • the sensor unit 1A of the first modification includes a first magnetosensitive element 11, a second magnetosensitive element 12, and a third magnetosensitive element 13 as magnetosensitive elements.
  • the third magnetosensitive element 13 is disposed at a third position E facing the upstream yoke 7 in the orthogonal direction Z orthogonal to the transport surface 2 and not facing the permanent magnet 5.
  • the third position E is only in a range where the resistance value of the third magnetosensitive element 13 arranged at the third position E when the medium 3 passes through the second magnetosensitive element 12 along the transport surface 2 is extremely small. It can be set to a position where the signal output from the third magneto-sensitive element 13 becomes substantially zero corresponding to the variation of the resistance value without changing.
  • the third magnetosensitive element 13 is magnetized by the permanent magnet 5.
  • the residual magnetic flux density of M is detected.
  • the third magnetosensitive element 13 does not detect a change in the bias magnetic field 4 due to the magnetic permeability of the magnetic pattern M. Accordingly, when the medium 3 is transported in the reverse transport direction X2, whether the magnetic pattern M is formed from a hard material or a soft material based on a signal from the third magnetosensitive element 13 is determined. Can be determined.
  • the magnetic information of the magnetic pattern M made of a hard material can be acquired based on the signal from the second magnetosensitive element 12 and the signal from the third magnetosensitive element 13, and based on the signal from the second magnetosensitive element 12.
  • Magnetic information of the magnetic pattern M made of a soft material can be acquired.
  • the sensor unit 1 ⁇ / b> B of Modification 2 includes a second permanent magnet 15 on the downstream side of the downstream yoke 6 in the transport direction X ⁇ b> 1.
  • the upstream yoke 7 is omitted.
  • the second permanent magnet 15 applies the second bias magnetic field 16 to the medium 3.
  • the first position A changes only within a very small range of the resistance value of the first magnetosensitive element 11 disposed at the first position A when the medium 3 passes the position facing the permanent magnet 5.
  • the signal output corresponding to the variation of the resistance value is substantially zero.
  • the first position A has a very small resistance value of the first magnetosensitive element 11 disposed at the first position A when the medium 3 passes the position facing the second permanent magnet 15. It can be set to a position where the signal that changes only within a certain range and the signal output corresponding to the change in the resistance value becomes substantially zero.
  • the first magnetosensitive element 11 when the medium 3 is transported in the reverse transport direction X2 passing through the second permanent magnet 15, the downstream yoke 6 and the permanent magnet 5 in this order, the first magnetosensitive element 11 is The residual magnetic flux density of the magnetic pattern M magnetized by the two permanent magnets 15 is detected. On the other hand, the first magnetosensitive element 11 does not detect a change in the bias magnetic field 16 due to the magnetic permeability of the magnetic pattern M. Therefore, when the medium 3 is transported in the reverse transport direction X2, whether the magnetic pattern M is formed of a hard material or a soft material based on a signal from the first magnetosensitive element 11 is determined. Can be determined.
  • the magnetic information of the magnetic pattern M made of a hard material can be acquired based on the signal from the first magnetosensitive element 11 and the signal from the second magnetosensitive element 12, and based on the signal from the second magnetosensitive element 12.
  • Magnetic information of the magnetic pattern M made of a soft material can be acquired.
  • the upstream yoke 7 may be provided in the sensor unit 1B. Further, a second downstream yoke may be provided on the downstream side of the second permanent magnet 15 in the transport direction X1. If these yokes are provided, the bias magnetic fields 4 and 16 generated by the permanent magnets 5 and 15 are prevented from spreading more than necessary. Accordingly, it is possible to prevent the first magnetosensitive element 11, the second magnetosensitive element 12, and the third magnetosensitive element from detecting a change in the magnetic field caused by the movement of a magnetic material different from the magnetic pattern M. Moreover, it can prevent or suppress that the 1st magneto-sensitive element 11, the 2nd magneto-sensitive element 12, and the 3rd magneto-sensitive element 13 are influenced from the magnetic field outside the sensor part 1B.
  • SYMBOLS 1 Sensor part, 2 ... Conveyance surface (moving surface), 3 ... Medium, 4 ... Bias magnetic field, 5 ... Permanent magnet, 6 ... Downstream side yoke, 7 ... Upstream side yoke, 11 ... 1st magnetoresistive element, 12 ... 2nd magnetic sensing element, 13 ... 3rd magnetic sensing element, 15 ... 2nd permanent magnet, 16 ... 2nd bias magnetic field, 20 ... Magnetic sensor apparatus, A ... 1st position, B ... 2nd position, E ... 3rd position, F ... Magnetosensitive direction, M ... Magnetic pattern, X1 ... Moving direction, Z ... Orthogonal direction

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Manufacturing & Machinery (AREA)
  • Artificial Intelligence (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Theoretical Computer Science (AREA)
  • Measuring Magnetic Variables (AREA)
  • Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)

Abstract

L'invention concerne un dispositif de capteur magnétique qui peut déterminer si un motif magnétique appliqué à un support est un matériau magnétique dur ou un matériau magnétique doux. De façon précise, le dispositif de détecteur magnétique (20) est pourvu d'une unité de capteur (1) destinée à détecter un motif magnétique (M) sur un support (3) transporté le long d'une surface de transport (2). L'unité de capteur (1) est équipée d'un aimant permanent (5) destiné à appliquer un champ magnétique de polarisation (4), d'une culasse côté aval (6) disposée côté aval de l'aimant permanent (5), d'un premier élément magnéto-sensitif (11) disposé dans une première position (A) qui est à l'opposé de la culasse côté aval (6) mais pas à l'opposé de l'aimant permanent (5) dans une direction perpendiculaire (Z) coupant perpendiculairement la surface de transport (2), et d'un second élément magnéto-sensitif (12) disposé dans une seconde position (B) qui est à l'opposé de l'aimant permanent (5) dans la direction perpendiculaire (Z). Le premier élément magnéto-sensitif (11) détecte seulement des changements dans le champ magnétique de polarisation (4) pouvant être attribués à la densité de flux magnétique résiduelle du motif magnétique (M) (matériau magnétique dur), et, par conséquent, il est possible de déterminer si le motif magnétique (M) appliqué sur le support (3) est un matériau magnétique dur ou un matériau magnétique doux.
PCT/JP2016/058775 2015-04-24 2016-03-18 Dispositif de capteur magnétique WO2016170885A1 (fr)

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JP2015-089684 2015-04-24

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JP6660191B2 (ja) * 2016-01-25 2020-03-11 株式会社ヴィーネックス 磁気センサ装置
WO2017191823A1 (fr) * 2016-05-06 2017-11-09 三菱電機株式会社 Dispositif de capteur magnétique
JP7020258B2 (ja) * 2018-04-06 2022-02-16 村田機械株式会社 位置検出システムおよび走行システム
WO2020149375A1 (fr) * 2019-01-17 2020-07-23 キヤノン電子株式会社 Capteur d'identification magnétique
JP6980166B1 (ja) * 2020-03-30 2021-12-15 三菱電機株式会社 磁気センサ装置

Citations (2)

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Publication number Priority date Publication date Assignee Title
WO2010052797A1 (fr) * 2008-11-10 2010-05-14 グローリー株式会社 Appareil de détection de propriété magnétique
JP2013120538A (ja) * 2011-12-08 2013-06-17 Nidec Sankyo Corp 磁気センサ装置

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JP5719515B2 (ja) * 2010-02-05 2015-05-20 日本電産サンキョー株式会社 磁気センサ装置
KR101564126B1 (ko) * 2010-12-28 2015-10-28 니혼 덴산 산쿄 가부시키가이샤 자기 센서 장치, 및 자기 센서 장치의 제조 방법
JP5979214B2 (ja) * 2012-02-13 2016-08-24 株式会社村田製作所 磁気センサ装置
WO2013153986A1 (fr) * 2012-04-09 2013-10-17 三菱電機株式会社 Capteur magnétique

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WO2010052797A1 (fr) * 2008-11-10 2010-05-14 グローリー株式会社 Appareil de détection de propriété magnétique
JP2013120538A (ja) * 2011-12-08 2013-06-17 Nidec Sankyo Corp 磁気センサ装置

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