WO2012137543A1 - Capteur magnétique - Google Patents

Capteur magnétique Download PDF

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Publication number
WO2012137543A1
WO2012137543A1 PCT/JP2012/053745 JP2012053745W WO2012137543A1 WO 2012137543 A1 WO2012137543 A1 WO 2012137543A1 JP 2012053745 W JP2012053745 W JP 2012053745W WO 2012137543 A1 WO2012137543 A1 WO 2012137543A1
Authority
WO
WIPO (PCT)
Prior art keywords
magnetoresistive element
magnet
magnetic sensor
case
magnets
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/JP2012/053745
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English (en)
Japanese (ja)
Inventor
濱口大輔
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Murata Manufacturing Co Ltd
Original Assignee
Murata Manufacturing Co Ltd
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.)
Filing date
Publication date
Application filed by Murata Manufacturing Co Ltd filed Critical Murata Manufacturing Co Ltd
Publication of WO2012137543A1 publication Critical patent/WO2012137543A1/fr
Anticipated expiration legal-status Critical
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Classifications

    • 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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/0047—Housings or packaging of magnetic sensors ; Holders
    • 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
    • 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
    • H10N50/80—Constructional details

Definitions

  • the present invention relates to a long magnetic sensor that detects a magnetic pattern printed on, for example, banknotes.
  • Patent Document 1 is disclosed as a magnetic sensor for discriminating an object to be detected such as a bill or a security printed with a predetermined pattern with magnetic ink or the like.
  • the vibration in the fundamental wave mode is a bending vibration in which both ends of the long magnetic sensor are fixed ends.
  • FIG. 1A shows a state in which no bending stress is applied to the long magnetic sensor.
  • a plurality of magnetoresistive elements 2, a plurality of magnets 5 that apply a magnetic field to the magnetic sensing portions of the plurality of magnetoresistive elements 2, and a case 1 that holds the magnetoresistive elements 2 and the magnets 5 are provided. Yes.
  • the plurality of magnets 5 and the plurality of magnets are arranged such that the position of the facing portion between the magnets 5 of the plurality of magnets 5 is the center position of a certain magnetoresistive element 2 of the plurality of magnetoresistive elements 2.
  • a resistance element 2 is arranged.
  • FIG. 1B is a partial sectional view exaggeratingly showing a state in which bending stress is applied to the long magnetic sensor.
  • the case 1 is a resin molded from a resin mold
  • the magnetoresistive element 2 and the magnet 5 are softer than the case 1. For this reason, when bending stress is applied to the long magnetic sensor, stress distortion occurs in the magnetoresistive element 2 corresponding to the facing portion (magnet joint position) between the magnet 5 and the magnet 5.
  • the magnetoresistive element 2 is made of an n-InSb material, InAs material, GaAs material, Ge material, or Si material having high electron mobility. Such a magnetoresistive element material has a piezoresistive effect. Therefore, when stress strain occurs in the magnetoresistive element 2, a signal due to the piezoresistive effect is superimposed, and this acts as noise (piezonoise).
  • the bending stress applied to the magnetoresistive element 2 can be reduced, but not only the distance accuracy between the magnetic sensor and the object to be detected is lowered, but also the amplitude of the bending vibration is increased. End up. Since the detection sensitivity of the magnetic material is affected by the square of the distance between the magnetic sensing portion of each magnetoresistive element of the magnetic sensor and the magnetic material to be detected, the flexibility of the case of the magnetic sensor cannot be used.
  • the stress strain applied to the magnetoresistive element 2 is reduced.
  • the opposing portion of the magnetoresistive element 2 and the magnetoresistive element 2 naturally has no magnetic sensitive part (disconnected)
  • the detection sensitivity of the magnetic material tends to decrease
  • the magnet 5 and the magnet 5 Since the opposing part has a tendency that the detection sensitivity of the magnetic material is lowered due to the small magnetic flux density, both sensitivity reduction factors overlap. Therefore, it is difficult to adopt a structure in which the magnet facing portion overlaps the magnetoresistive element facing portion.
  • the present invention has been made in view of the above-described problems, and an object thereof is to provide a magnetic sensor that solves the above-described piezo noise problem caused by bending vibration accompanying the increase in length of the magnetic sensor.
  • the magnetic sensor of the present invention includes a plurality of magnetoresistive elements, a plurality of magnets, and a case for holding the plurality of magnetoresistive elements and the plurality of magnets, and the case includes the plurality of magnetoresistive elements in series. And a magnet holding part for holding the plurality of magnets in series so as to apply a magnetic field to the magnetoresistive element placed on the magnetoresistive element placing part.
  • the plurality of magnets and the plurality of magnetoresistive elements include a magnet facing portion, which is a facing portion between the magnets of the plurality of magnets, and a magnetoresistive element and a magnetoresistive element of the plurality of magnetoresistive elements.
  • the case includes a protrusion formed on a part of the magnetoresistive element mounting portion corresponding to the position of the magnet facing portion, The magnetoresistive element placed on the magnetoresistive element placing part corresponding to the position of the magnet facing part is joined to the protruding part via an adhesive.
  • FIG. 1A is a cross-sectional view of a conventional general long type magnetic sensor in a state where no bending stress is applied.
  • FIG. 1B is a partial cross-sectional view in a state where bending stress is applied to the long magnetic sensor.
  • 2A is an external perspective view in the middle of attaching the cover of the long magnetic sensor 201 according to the first embodiment, and
  • FIG. 2B is an external perspective view in a state in which the cover is attached.
  • FIG. 3 is a front view showing a structure in which the magnetic sensor 201 is incorporated into an installation destination device.
  • FIG. 4A is a partial plan view of the magnetic sensor 201.
  • FIG. 4B is a partial view of the central longitudinal cross section of the magnetic sensor 201 in the longitudinal direction.
  • FIG. 5 is a partial perspective view of the case 1 as viewed from the magnet holding portion 14 side.
  • FIG. 6 is a comparative example of piezo noise generated between the conventional magnetic sensor and the magnetic sensor 201 according to the first embodiment of the present invention.
  • FIG. 7A is a partial plan view of the magnetic sensor 202 of the second embodiment.
  • FIG. 7B is a partial view of the central longitudinal cross section of the magnetic sensor 202 in the longitudinal direction.
  • FIG. 2A is an external perspective view in the middle of attaching the cover of the long magnetic sensor 201 according to the first embodiment
  • FIG. 2B is an external perspective view in a state in which the cover is attached.
  • the case 1 made of synthetic resin has magnetoresistive elements 2a, 2b, 2c, 2d.
  • a terminal pin 6 that conducts to the plurality of magnetoresistive elements 2a, 2b, 2c, 2d,.
  • Claw engaging grooves 3 are provided on both sides of the case 1 along the longitudinal direction.
  • the cover 4 made of metal is provided with a cover fixing claw portion that engages with the claw portion engagement groove 3 of the case. As shown, a cover 4 is covered on top of the case 1.
  • the object to be detected 100 is conveyed in a direction substantially perpendicular to the longitudinal direction of the long magnetic sensor 201 as indicated by an arrow in the figure.
  • FIG. 3 is a front view showing a structure in which the magnetic sensor 201 is incorporated into an installation destination device.
  • the magnetic sensor 201 is mounted on the circuit board 110 via the terminal pins 6.
  • the circuit board 110 is held by a holder 120, and the holder 120 is fixed to a frame or the like of an installation destination device.
  • FIG. 4A is a partial plan view of the magnetic sensor 201. However, the cover 4 shown in FIG. 2 is shown in a removed state.
  • FIG. 4B is a partial view of the central longitudinal section in the longitudinal direction of the magnetic sensor 201.
  • FIG. 5 is a partial perspective view of the case 1 as viewed from the magnet holding portion 14 side.
  • the magnet holding part 14 is a recess formed in the lower part of the case 1, and the magnet 5 is accommodated in the magnet holding part 14.
  • the case 1 is resin-molded.
  • a plurality of magnetoresistive element mounting portions 13i, 13j, 13k and the like are formed on the upper portion of the case 1.
  • the lower surfaces of these magnetoresistive element mounting portions 13i, 13j, 13k and the like are magnetoresistive element facing surfaces.
  • Magnets 5 are housed in a plurality of magnet holding portions 14 formed in the lower part of case 1.
  • the magnet 5 is filled with a filler 8 such as an epoxy resin so that the magnet 5 is embedded in the magnet holding portion 14.
  • a protrusion 11 is formed on a part of the magnetoresistive element mounting portion corresponding to the position of the facing portion between the magnet 5 and the magnet 5 of the case 1.
  • the engraved portion 12 is formed in a region other than the joint portion which is a part of the magnetoresistive element mounting portion (in this example, the portion where the central portion of the magnetoresistive element is opposed).
  • the magnetoresistive element 2j is joined to the protruding portion 11 via the adhesive layer 7.
  • the protrusion part is not formed in the magnetoresistive element mounting part which is not the position of the opposing part of the magnet 5 of the case 1 and the magnet 5.
  • FIG. The magnetoresistive elements 2i and 2k are bonded to the almost entire surface of the magnetoresistive element mounting portion via the adhesive layer 7.
  • the magnetoresistive elements 2i, 2j, 2k, etc. are bonded to the magnetoresistive element mounting portion on the opposite side of the magnetosensitive element so that the magnetosensitive part is on the upper surface side.
  • the electrode pad of the magnetoresistive element is joined to the inner lead of the lead frame, and the outer lead of the lead frame is thermocompression bonded to the terminal pin 6, but in FIG. Illustration of these leads is omitted.
  • the height of the protruding portion 11 is determined so that the height of the magnetically sensitive parts such as the magnetoresistive elements 2i and 2k joined to the magnetoresistive element placement parts 13i and 13k of the case 1 that are not positioned is uniform. Yes. That is, when the thickness of the adhesive layer 7 is constant, the height of the protruding portion 11 is equal to the height of the magnetoresistive element mounting portions 13i, 13k, etc. that are not the positions of the opposing portions of the magnet 5 and the magnet 5. .
  • the magnetoresistive element 2j joined to the magnetoresistive element mounting portion 13j of the case 1 corresponding to the position of the facing portion between the magnet 5 and the magnet 5 is a part of the lower surface of the magnetoresistive element mounting portion 13j. 1B, even if a bending stress as shown in FIG. 1B is applied to the magnetic sensor 201, the magnetoresistive element by bending at the position of the facing portion between the magnet 5 and the magnet 5 of the case 1 is applied. The bending moment to 2j is reduced. That is, the flat state is maintained with almost no influence of bending at the position of the facing portion between the magnet 5 and the magnet 5 of the case 1. This suppresses the generation of piezo noise.
  • FIG. 6 shows a comparative example of piezo noise generated between the conventional magnetic sensor and the magnetic sensor 201 according to the first embodiment of the present invention.
  • Ch.A (before) is piezo noise generated in the channel A of the conventional magnetic sensor
  • Ch.B (before) is piezo noise generated in the channel B of the conventional magnetic sensor.
  • Ch.A (after) is piezo noise generated in the channel A of the magnetic sensor 201 of the first embodiment
  • Ch.B (after) is piezo noise generated in the channel B of the magnetic sensor 201 of the first embodiment. is there.
  • the channel A corresponds to the sixth magnetoresistive element corresponding to the position of the opposing portion of the magnet 5 among the 18 channels (18 magnetoresistive elements) in total.
  • the channel B corresponds to the eleventh magnetoresistive element corresponding to the position of another facing portion between the magnet 5 and the magnet 5.
  • the horizontal axis represents frequency and the vertical axis represents piezo noise voltage. Both are relative value scales. As shown in FIG. 6, since a mountain shape in which piezo noise rises at a predetermined frequency is drawn, it can be seen that bending vibration is generated at the resonance frequency, and large piezo noise is generated at this resonance frequency. Compared to the magnetic sensor having the conventional structure, the piezo noise can be reduced to about 1/6 or less in the magnetic sensor 201 of the first embodiment.
  • a partition 15 of a magnet-like holding part is disposed below the protrusion 11 of the case 1.
  • the partition 15 and the protruding portion 11 of the magnet holding portion are formed of resin that flows in the space of the molding die. Since the mold gate opening is located at a position corresponding to both end positions in the longitudinal direction of the case 1, the resin flows entirely in the longitudinal direction of the case 1 during molding. At that time, the space for forming the partition 15 of the magnet holding portion acts as a resin flow path, and the resin is easily injected into the space for forming the protruding portion 11. Therefore, molding defects such as short shots in resin molding do not easily occur, and the protruding portion 11 is reliably formed.
  • FIG. 7A is a partial plan view of the magnetic sensor 202 of the second embodiment. However, it is shown with the cover removed.
  • FIG. 7B is a partial view of the central longitudinal cross section of the magnetic sensor 202 in the longitudinal direction.
  • Case 1 is resin molded.
  • a plurality of magnetoresistive element mounting portions 13i, 13j, 13k and the like are formed on the upper portion of the case 1.
  • the lower surfaces of these magnetoresistive element mounting portions 13i, 13j, 13k and the like are magnetoresistive element facing surfaces.
  • magnet holders 14 for storing a plurality of magnets 5 are formed in the lower part of the case 1, and the magnets 5 are respectively stored in these magnet holders 14.
  • the periphery of the magnet 5 is filled with a filler 8 such as an epoxy resin.
  • the protrusion assembly 16 is formed on a part of the magnetoresistive element mounting part corresponding to the position of the opposing part between the magnet 5 and the magnet 5 of the case 1 (in this example, the part where the central part of the magnetoresistive element is opposed). Yes.
  • the magnetoresistive element 2j is joined to the protrusion assembly 16 via the adhesive layer 7.
  • the protrusion assembly portion is not formed on the magnetoresistive element mounting portion which is not the position of the facing portion between the magnet 5 and the magnet 5 of the case 1.
  • the magnetoresistive elements 2i and 2k are bonded to the almost entire surface of the magnetoresistive element mounting portion via the adhesive layer 7.
  • the engraved portion is not formed in a region other than the projection assembly portion of the magnetoresistive element mounting portion.
  • the height of the magnetoresistive element joined to the magnetoresistive element mounting portion 13j of the case 1 corresponding to the position of the facing portion between the magnet 5 and the magnet 5 is mainly determined by the height of the protrusion assembly portion 16. Further, the height of the magnetoresistive elements 2i, 2k, etc. joined to the magnetoresistive element mounting portions 13i, 13k, etc. of the case 1 which is not the position of the opposing portion between the magnets 5 and 5 is mainly the thickness of the adhesive layer 7. Stipulated in
  • the magnetoresistive element 2j to be joined to the magnetoresistive element mounting portion 13j of the case 1 corresponding to the position of the opposing portion between the magnet 5 and the magnet 5 is part of the lower surface of the magnetoresistive element mounting portion 13j. Even if a bending stress as shown in FIG. 1B is applied to the magnetic sensor 201 due to the bonding, the magnetoresistive element 2j by bending at the position of the magnet 5 of the case 1 facing the magnet 5 is used. The bending moment is reduced. That is, the flat state is maintained with almost no influence of bending at the position of the facing portion between the magnet 5 and the magnet 5 of the case 1. This suppresses the generation of piezo noise.
  • the piezo noise reduction effect of the magnetic sensor 202 of the second embodiment is substantially the same as that of the magnetic sensor 201 of the first embodiment.
  • the protrusion part 11 is formed in a part of magnetoresistive element mounting part corresponding to the position of the opposing part of the magnet 5 of the case 1 and the magnet 5, and magnetoresistive element mounting part other than that is formed. No protrusion is formed on the.
  • a protruding portion may be formed on the magnetoresistive element mounting portion where stress is hardly applied by bending the magnetic sensor.
  • protrusions may be formed on all the magnetoresistive element mounting parts, and each magnetoresistive element may be bonded to the protrusions via an adhesive.
  • a protrusion assembly portion as shown in the second embodiment may be formed on the magnetoresistive element mounting portion where stress is hardly applied by bending of the magnetic sensor.
  • the protrusion assembly portions may be formed on all the magnetoresistive element mounting portions, and each magnetoresistive element may be bonded to the protrusion assembly portion via an adhesive.

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  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Magnetic Variables (AREA)

Abstract

Selon l'invention, une pluralité de sections de montage d'éléments de résistance magnétique (13i, 13j, 13k), etc., sont formées sur la section supérieure d'un boîtier (1). Des sections de support d'aimant (14) qui renferment une pluralité d'aimants (5) sont formées dans la section inférieure du boîtier (1), et les aimants (5) sont renfermés dans chacune de ces sections de support d'aimant (14). Une section saillante (11) est formée dans une partie de la section de montage d'éléments de résistance magnétique (13g) correspondant à une position faisant face à l'aimant (5) et de l'aimant (5) dans le boîtier (1). Un élément de résistance magnétique (2j) est lié à cette section saillante (11) par l'intermédiaire d'une couche adhésive (7). En résultat, un capteur magnétique est configuré, celui-ci n'étant pas susceptible de générer un bruit piézoélectrique même si l'amplitude d'une vibration de courbure provoquée par une vibration sympathique en association avec l'allongement du capteur magnétique augmente.
PCT/JP2012/053745 2011-04-01 2012-02-17 Capteur magnétique Ceased WO2012137543A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2011-081932 2011-04-01
JP2011081932 2011-04-01

Publications (1)

Publication Number Publication Date
WO2012137543A1 true WO2012137543A1 (fr) 2012-10-11

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PCT/JP2012/053745 Ceased WO2012137543A1 (fr) 2011-04-01 2012-02-17 Capteur magnétique

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WO (1) WO2012137543A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016013438A1 (fr) * 2014-07-25 2016-01-28 三菱電機株式会社 Dispositif de capteur magnétique et son procédé de fabrication
JP2016125861A (ja) * 2014-12-26 2016-07-11 セイコーＮｐｃ株式会社 磁気ラインセンサ
JP2016125860A (ja) * 2014-12-26 2016-07-11 セイコーＮｐｃ株式会社 磁気ラインセンサにおける磁石の位置決め方法及び位置決め装置
WO2019017219A1 (fr) * 2017-07-19 2019-01-24 三菱電機株式会社 Dispositif capteur magnétique

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000339628A (ja) * 1999-05-26 2000-12-08 Kyocera Corp 磁気ヘッド加工用治具
JP2002204001A (ja) * 2000-12-28 2002-07-19 Teikoku Tsushin Kogyo Co Ltd 磁気信号検出素子及びその製造方法
WO2005083457A1 (fr) * 2004-02-27 2005-09-09 Murata Manufacturing Co., Ltd. Capteur magnétique prolongé

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000339628A (ja) * 1999-05-26 2000-12-08 Kyocera Corp 磁気ヘッド加工用治具
JP2002204001A (ja) * 2000-12-28 2002-07-19 Teikoku Tsushin Kogyo Co Ltd 磁気信号検出素子及びその製造方法
WO2005083457A1 (fr) * 2004-02-27 2005-09-09 Murata Manufacturing Co., Ltd. Capteur magnétique prolongé

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016013438A1 (fr) * 2014-07-25 2016-01-28 三菱電機株式会社 Dispositif de capteur magnétique et son procédé de fabrication
JP5881925B1 (ja) * 2014-07-25 2016-03-09 三菱電機株式会社 磁気センサ装置およびその製造方法
JP2016125861A (ja) * 2014-12-26 2016-07-11 セイコーＮｐｃ株式会社 磁気ラインセンサ
JP2016125860A (ja) * 2014-12-26 2016-07-11 セイコーＮｐｃ株式会社 磁気ラインセンサにおける磁石の位置決め方法及び位置決め装置
WO2019017219A1 (fr) * 2017-07-19 2019-01-24 三菱電機株式会社 Dispositif capteur magnétique
JP6494895B1 (ja) * 2017-07-19 2019-04-03 三菱電機株式会社 磁気センサ装置
US10634739B2 (en) 2017-07-19 2020-04-28 Mitsubishi Electric Corporation Magnetic sensor device

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