JP2006284466A - Magnetic detecting sensor, and magnetic substance detector - Google Patents

Magnetic detecting sensor, and magnetic substance detector Download PDF

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Publication number
JP2006284466A
JP2006284466A JP2005106986A JP2005106986A JP2006284466A JP 2006284466 A JP2006284466 A JP 2006284466A JP 2005106986 A JP2005106986 A JP 2005106986A JP 2005106986 A JP2005106986 A JP 2005106986A JP 2006284466 A JP2006284466 A JP 2006284466A
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Japan
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magnetic
magnetic field
coil
pattern
element
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Pending
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JP2005106986A
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Japanese (ja)
Inventor
Fumio Kaneko
Osamu Maeda
Hiroshi Nakamura
寛 中村
修 前田
文夫 金子
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Nikkoshi Co Ltd
ニッコーシ株式会社
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Priority to JP2005106986A priority Critical patent/JP2006284466A/en
Publication of JP2006284466A publication Critical patent/JP2006284466A/en
Application status is Pending legal-status Critical

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Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic detecting sensor capable of measuring a magnetic characteristic of a portion in an area as narrow as possible of a detected pattern, by a magnetic detecting part and a bias magnetic field impressing coil, and a magnetic substance detector using the magnetic detecting sensor. <P>SOLUTION: A fine magnetic substance pattern is detected by the magnetic detecting sensor of structure with a Hall element chip 11 and the magnetic field impressing coil 6 mounted on the same substrate 1. The magnetic substance detector is constituted to obtain a high S/N ratio of signal by allow a pulse-like current to flow in the coil 6, or to obtain a signal due to the magnetic substance by changing a level of the pulse-like current. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a magnetic detection sensor and a magnetic detection device that measure a magnetic flux density changed by a magnetic material by applying a magnetic field to adjacent magnetic materials using a magnetic material detection element.

  Conventionally, using a semiconductor magnetoresistive element, a bias magnetic field is applied to the semiconductor magnetoresistive element by a permanent magnet, and a magnetic print pattern close to the surface of the semiconductor magnetoresistive element is used as a signal of resistance change of the semiconductor magnetoresistive element. There is a magnetic sensor to read. In recent years, magnetic patterns tend to become more complicated, for example, by using a plurality of types of magnetic inks having different magnetization characteristics for inks that have a finer magnetic printing pattern and that contain magnetic substances of the magnetic printing pattern.

  FIG. 3 is a cross-sectional view of Conventional Example 1 of a magnetic sensor 30 using a semiconductor magnetoresistive element for reading a magnetic print pattern. A magnetoresistive element 31 made of single crystal indium antimony (InSb) is installed in a case 35, and a magnetic pattern is read on the case upper surface 39 of FIG. A permanent magnet 32 is installed on the back surface of the magnetoresistive element 31 to apply a bias magnetic field to the magnetoresistive element 31. In the magnetic sensor 30, the width of the magnetic sensitive pattern of the magnetoresistive element 31 is about 0.5 mm. Therefore, when reading a printed magnetic pattern of 0.5 mm or less, the width of the magnetic sensitive pattern is relatively large. It is difficult to obtain the output of the element in accordance with the printed magnetic pattern, and an averaged signal of the magnetic pattern can be obtained.

Further, in the magnetic sensor 30 shown in FIG. 3, when a pattern to be detected by two kinds of magnetic inks each containing a magnetic material having different magnetization characteristics is printed close in width of 0.5 mm or less, the magnetoresistive element The area of the magnetic sensing pattern 31 is larger than the detected pattern printed in close proximity, and the output of the magnetoresistive element 31 is an output obtained by averaging the outputs of the two types of magnetic inks. The output corresponding to the pattern cannot be obtained. These phenomena can be regarded as a problem that the resolution of the magnetic pattern reading device using the semiconductor magnetoresistive element does not have sufficient resolution with respect to the detected pattern of the magnetic ink.

There is a strong demand that the magnetic detection pattern of the magnetic field detection element is equal to or smaller than the width of the detected pattern of the magnetic ink and that the detected pattern can be detected by an electrical signal corresponding to the detected pattern of the magnetic ink.

As a means for reducing the magnetic sensitive pattern of the magnetic field detecting element, there is a method of using a Hall element having a smaller magnetic sensitive pattern as the magnetic field detecting element. The width of the magnetic sensitive pattern of the Hall element can be about 10 μm, and the magnetic pattern can be read with a resolution close to this pattern width.

FIG. 5 shows a principle diagram of the Hall element. As shown in FIG. 5, the input / output wiring of the Hall element is formed by forming an input electrode 52 and an output electrode 53 at two opposing positions of the semiconductor thin plate 51 and applying a voltage Vc between the input electrodes 52 to thereby form the semiconductor thin plate 51. The output voltage VH corresponding to the magnetic field strength B in the direction perpendicular to the output electrode 53 is output between the output electrodes 53. When the voltage Vc between the input electrodes 52 is constant, the voltage VH between the output electrodes 53 is substantially proportional to the magnetic field strength B. The width of the magnetic sensitive pattern of the Hall element is the width w shown in FIG. 5 of the semiconductor thin plate.

A schematic diagram of a magnetic field strength sensor using the Hall element of FIG. A Hall element 41 is mounted as a magnetic field detection element, and a magnetic field generating coil 42 is connected to the output side of the Hall element 41, and a current obtained by amplifying the Hall element output can be passed through the magnetic field generating coil 42. A possible amplification amplifier 43 is connected. A current for canceling the magnetic field is supplied from the amplifier 43 to the magnetic field generating coil 42 in accordance with the magnetic field strength. According to this method, an output independent of the sensitivity and temperature characteristics of the Hall element is obtained. However, this conventional example 2 is not intended to measure the magnetization characteristics of a fine pattern by printed magnetic ink, but is intended to measure the magnetic field strength as an average value of the space. Therefore, the magnetic field generating coil 42 is installed behind the Hall element 41, and it is not assumed that the magnetic body is brought close to the detection unit of the magnetic field strength sensor 40.

In addition, as a conventional example, there is an example in which a magnetic bias is applied to the Hall element with an electromagnet in order to increase the detection sensitivity of the magnetic substance of the magnetic field detection element. It is shown in Patent Document 2 and is referred to as Conventional Example 3. However, this conventional example 3 is intended to detect the passage of the magnetic body through the space between the magnet and the electromagnet. The electromagnet and the permanent magnet are arranged on both sides of the moving magnetic body, and the electromagnet is sandwiched between them. It has a complicated configuration in which two Hall elements are arranged. Further, a permanent magnet or a coil for applying a magnetic bias to the magnetic body and the magnetic field detection element is also provided behind the magnetic field detection element. Conventional Example 3 is configured to detect a magnetic flux passing through a magnetic body between a permanent magnet and an electromagnet, and is not intended to directly detect a fine magnetic pattern close to the magnetic field detection element. It is not the size and composition for grasping the position.
JP 2001-91612 A JP 2002-267405 A

  In a conventional sensor that detects a close magnetic material by a change in magnetic field, the magnetic sensing element pattern of the magnetic field detection element is generally large, and when the magnetic measurement result is to be recognized as a magnetic distribution, the magnetic detection sensor detects the magnetic field detection part. It is difficult to accurately grasp which position is detected and the relative position to the object to be measured. In order to accurately grasp the position of the measurement object and the magnetic measurement sensor and obtain more accurate magnetic distribution data, the detection pattern of the magnetic field detection element is compared with the detection pattern including the magnetic material to be measured. It must be small enough and close enough.

For the bias magnetic field application coil, it is necessary to apply magnetism only to a limited range, so the coil must also be made small. The problem was to make the structures close to each other.

For two or more detected patterns having different types of magnetic substances to be contained, it is necessary to set a detection method that can clearly show that the magnetization characteristics of the magnetic substances contained in the respective detected patterns are different.

  The present invention provides a magnetic detection sensor and a magnetic body detection device using the magnetic detection sensor, in which the magnetic detection unit and the bias magnetic field application coil can measure the magnetic characteristics of the portion of the pattern to be detected as small as possible. For the purpose. As a means for achieving the above object, a magnetic detection sensor capable of reading out a fine magnetic pattern by mounting a magnetic field detection element and a coil as close as possible and placing the magnetic detection element and a coil close to the pattern to be detected. And the magnetic body detection apparatus using this sensor is provided. As a means for this purpose, the coil and the magnetic field detecting element are arranged so that the magnetic sensing pattern of the magnetic field detecting element is placed in the coil while the center of the magnetic sensitive surface of the magnetic field detecting element is aligned with the center of the coil in the circumferential direction. A magnetic detection sensor is configured by mounting.

The magnetic field detection element and the coil are arranged on the same substrate with the magnetic field generation center line of the coil perpendicular to the substrate, and the magnetic field generation center line of the coil is aligned with the center of the magnetic sensing pattern of the magnetic field detection element. The installation area of the coil and the magnetic field detection element can be minimized. In order to achieve the configuration in which the magnetic field is efficiently applied to the magnetic field detection element that is the smallest in the coil length direction, the magnetic sensing pattern of the magnetic field detection element is provided inside the coil.

In addition, a magnetic field having a different magnitude is applied to a magnetic pattern having two or more different magnetic characteristics by changing the magnitude of the current passed through the coil, and the output of the magnetic field detection element in each magnetic field is measured. It can be set as the magnetic body detection apparatus which detects the magnetic pattern from which a magnetic characteristic differs by detecting the change of the output of a magnetic field detection element with respect to the change of the electric current sent through a coil, and calculating the change rate of a magnetic field detection element.

As a method for changing the magnitude of the current flowing through the coil, a magnetic field is applied by an alternating current. By setting the current flowing through the coil to alternating current, the amount of heat generated can be suppressed and a current larger than direct current can be flowed, and a larger magnetic field can be applied compared to the direct current magnetic field. By increasing the output signal, it is possible to accurately measure the output of the magnetic field detection element. Further, a signal having a large S / N ratio can be obtained by amplifying the signal by synchronizing the output of the magnetic field detecting element with the alternating current. As a result, the magnetic material pattern can be read with high accuracy.

According to the magnetic detection sensor of the present invention, a magnetic field detection element and a coil are mounted as close as possible, and a magnetic field detection element and a coil can be installed as close as possible to an object to be detected. It is possible to obtain magnetic pattern distribution data with high accuracy. In addition, when two or more magnetic patterns having different magnetic characteristics exist in close proximity as the object to be measured, the magnetic patterns having different magnetic characteristics can be identified by comparing the change rates of the magnetic characteristics.

A fine magnetic pattern can be read by allowing the magnetic field detection element of the magnetic detection sensor and the direction of the magnetic field to be applied to the coil to be close to each other with the same center and flowing an alternating current through the coil. Further, the rate of change of the output of the magnetic field detection element can be obtained by passing two or more different alternating currents through the coil installed close to the magnetic field detection element as the magnetic field applied to the magnetic field detection element. Examples will be described below.

  FIG. 1 shows a magnetic detection sensor according to a first embodiment of the present invention. 1a is a cross-sectional view and FIG. 1b is a plan view. An indium antimony (InSb) Hall element chip 22 formed on the glass substrate 2 as a magnetic field detection element is mounted on the glass epoxy substrate 5. An indium antimony (InSb) layer 2 is formed on the glass substrate 2 as a Hall element operation layer, and an electrode layer 3 for taking out an electrode is formed on a part of the indium antimony (InSb) layer 3. One of the gold wires 4 connected to the electrode layer 5 is connected to the wiring pattern 8 on the glass epoxy substrate 1 to form input / output conductors. The bottom surface of the Hall element chip 22, which is a magnetic field detection element, is fixed on the glass epoxy substrate 1 via the epoxy resin 7. The surface on which the InSb layer 2 of the Hall element is formed is covered with an epoxy layer 7 for protection.

The coil 11 is mounted on the glass epoxy substrate 1, and the surface of the coil 11 that is in contact with the substrate and the surface on which the Hall element chip 22 is mounted are on the same surface of the glass epoxy substrate. The center of the magnetosensitive pattern of the element chip is configured to match. Therefore, the center line of the magnetic field generated by the coil passes through the center of the magnetic sensitive pattern of the Hall element. Further, since the magnetic sensing pattern of the Hall element is formed on the surface facing the glass epoxy substrate surface of the Hall element chip 22, it is in the coil 11. With this configuration, the distance between the coil 11 and the Hall element chip 22 is minimized. Further, if the magnetic material to be measured is placed on the surface of the glass epoxy substrate on which the Hall element and the coil are mounted, the thickness of the glass epoxy substrate 1 and the thickness of the Hall element chip 22 are added. The distance is the distance between the surface of the magnetic material to be detected and the Hall element chip magnetosensitive surface, which is the shortest in this configuration.

The operation of this magnetic sensor will be described. The magnetic field generated from the coil 11 passes through the Hall element chip 22 to form a magnetic flux circuit having a closed loop around the coil. When a magnetic material is placed close to the front surface of the coil, the magnetic flux circuit is deformed according to the magnetic permeability of the magnetic material, and the magnetic flux density applied perpendicularly to the Hall element chip changes. Since the magnetic flux density applied to the Hall element chip changes in proportion to the magnetic permeability of the magnetic body, the output of the Hall element chip is an output corresponding to the magnetic permeability of the magnetic body.

  When the magnitude of the magnetic field applied to the magnetic material is changed by changing the level of the current flowing through the coil, the change in the output changes depending on the type of the magnetic material according to the change in the magnitude of the magnetic field. The difference between the output of the magnetic field detection element at one current level and the output of the magnetic field detection element at a different current level can be regarded as the rate of change with respect to the change in the current flowing through the coil.

  When the current flowing through the coil is alternating current, the amount of heat generated can be suppressed more than direct current, so that a larger current than direct current can be passed at the peak of alternating current. A signal with a large S / N ratio can be obtained by amplifying the output of the Hall element in synchronism with the frequency of the AC flowing through the coil. If the alternating current level flowing through the coil is changed periodically, the magnitude of the magnetic field applied to the magnetic material can be changed periodically, and the output of the magnetic field detection element corresponding to this can be changed periodically. Therefore, the type of the magnetic material can be specified by comparing the data with respect to the magnetic material acquired in advance according to how the output changes.

  The alternating current flowing through the coil may be not only + −symmetrical alternating current but also + −asymmetrical alternating current to which a direct current bias is applied.

Example 1 is an example in which the Hall element as a magnetic field detection element is made of InSb (indium antimony), but the material can be Ge (germanium) or InAs (indium arsenide). is there.

  FIG. 2 shows a magnetic detection sensor according to a second embodiment of the present invention. 2a is a sectional view and FIG. 2b is a plan view. An indium antimony (InSb) Hall element chip 22 formed on the glass substrate 2 as a magnetic field detection element is mounted in the glass epoxy substrate 1. An indium antimony (InSb) layer 3 is formed as a Hall element operation layer on the glass substrate 2, and an electrode layer 5 for taking out an electrode is formed on a part of the indium antimony (InSb) layer 3. One of the gold wires 4 connected to the electrode layer 5 is connected to the wiring pattern 8 on the glass epoxy substrate 1 to form input / output conductors. The glass substrate 1 of the magnetic field detection element is fixed in the hole of the glass epoxy substrate 1 with an epoxy resin 6. The holes in the glass epoxy substrate 1 penetrate the glass epoxy substrate 1. The glass substrate 1 of the Hall element chip 22 is fixed to the glass epoxy substrate 5 through the epoxy resin 6 on the side surface and the bottom surface.

A step 12 in which the hole on the Hall element wiring side becomes smaller is formed on the side surface of the through hole formed in the glass epoxy substrate 1, and the coil 11 is mounted in the hole. The coil 11 is mounted from the back surface on which the wiring of the Hall element is formed. The conductive wire pattern 9 connected to the coil is formed on the back surface of the glass epoxy substrate 1 on which the Hall element conductive wire pattern 8 is formed. The magnetic sensing surface of the Hall element chip 22 is installed so as to be inside the coil 6, and the center of the circle of the coil 6 and the center of the sensor pattern of the Hall element chip are mounted so as to coincide. With this configuration, the distance between the coil 8 and the Hall element chip 22 is minimized. When the magnetic material to be measured is placed on the surface of the glass epoxy substrate 1 on which the coil 11 is mounted, the distance between the surface of the magnetic material to be measured and the coil or Hall element chip is the same as that of the glass epoxy substrate 1. Less than the thickness. The distance between the surface of the magnetic material to be measured and the coil or Hall element chip is smaller than that in Example 1. The surface of the magnetic Hall element chip 22 on which the InSb layer 2 is formed is covered with an epoxy layer 7 for protection.

  The operation of this sensor is the same as in the first embodiment.

Example 2 is an example in which the Hall element as a magnetic field detection element is made of InSb (indium antimony), but the material can be Ge (germanium) or InAs (indium arsenide). is there.

This magnetic detection sensor can be applied as a magnetic substance detection probe for detecting a complicated and fine magnetic pattern.
In addition, a magnetic body detection apparatus using the magnetic detection sensor can extract a magnetic change caused by the magnetic body pattern as an electric signal by moving the magnetic detection sensor, and can draw the magnetic pattern as a change in magnetic intensity.

It is a block diagram which shows the 1st Example of the magnetic detection sensor by this invention. It is a block diagram which shows the 2nd Example of the magnetic detection sensor by this invention. It is a block diagram which shows the prior art example which detects a magnetic pattern using a magnetoresistive element. It is a block diagram which shows the prior art example of the magnetic field intensity sensor which uses a Hall element. It is a principle diagram of a Hall element.

Explanation of symbols

1 Glass epoxy substrate 2 Glass substrate 3 InSb layer 4 Au wire 5 Electrode layer 6 Resin 7 Resin 8 Conductive pattern 9 Coil conductive pattern 11 Coil 12 Step 22 Hall element chip 30 Magnetic sensor 31 Magnetoresistive element 32 Permanent magnet 33 Substrate 34 External Connection terminal 35 Case 37 Case ground terminal 38 Injection resin 39 Case upper surface 40 Magnetic field strength sensor 41 Hall element 42 Magnetic field generation coil 43 Amplifier 41 Hall element 42 Magnetic field generation coil 43 Amplifier 51 Semiconductor thin plate 52 Input electrode 53 Output electrode

Claims (3)

  1. A magnetic field detecting element for outputting an electric signal by an external magnetic field; and a magnetic field generating coil for applying a bias magnetic field to the magnetic field detecting element. The magnetic field generating coil and the magnetic field detecting element are mounted on the same substrate. In addition, the magnetic field detecting element is installed inside the magnetic field generating coil, and the center of the magnetic field generated from the magnetic field generating coil is coincident with the center of the magnetic field detecting element in the vertical direction. Magnetic detection sensor.
  2. 2. The magnetic detection sensor according to claim 1, wherein the magnetic field detection element is a Hall element, and the material thereof is Ge (germanium), InSb (indium antimony), or InAs (indium arsenide).
  3. A magnetic substance detection apparatus using the magnetic detection sensor, wherein an alternating current is passed through the magnetic field generating coil.
JP2005106986A 2005-04-04 2005-04-04 Magnetic detecting sensor, and magnetic substance detector Pending JP2006284466A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016519310A (en) * 2013-05-10 2016-06-30 アレグロ・マイクロシステムズ・エルエルシー Magnetic field sensor resistant to external magnetic effects
US10310028B2 (en) 2017-05-26 2019-06-04 Allegro Microsystems, Llc Coil actuated pressure sensor
US10324141B2 (en) 2017-05-26 2019-06-18 Allegro Microsystems, Llc Packages for coil actuated position sensors

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016519310A (en) * 2013-05-10 2016-06-30 アレグロ・マイクロシステムズ・エルエルシー Magnetic field sensor resistant to external magnetic effects
US9664494B2 (en) 2013-05-10 2017-05-30 Allegro Microsystems, Llc Magnetic field sensor with immunity to external magnetic influences
US10310028B2 (en) 2017-05-26 2019-06-04 Allegro Microsystems, Llc Coil actuated pressure sensor
US10324141B2 (en) 2017-05-26 2019-06-18 Allegro Microsystems, Llc Packages for coil actuated position sensors

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