CN203204700U - Magnetic head used for detecting magnetic field on surface of magnetic pattern based on magneto-resistance technology - Google Patents
Magnetic head used for detecting magnetic field on surface of magnetic pattern based on magneto-resistance technology Download PDFInfo
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- CN203204700U CN203204700U CN 201320191112 CN201320191112U CN203204700U CN 203204700 U CN203204700 U CN 203204700U CN 201320191112 CN201320191112 CN 201320191112 CN 201320191112 U CN201320191112 U CN 201320191112U CN 203204700 U CN203204700 U CN 203204700U
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Abstract
The utility model discloses a magnetic head used for detecting the magnetic field on the surface of a magnetic pattern based on the magneto-resistance technology, which comprises a bracket, a PCB board arranged on the bracket, a horizontal excitation structure used for generating a magnetic field parallel to the surface of the magnetic head, and a magnetic field detection component used for detecting the distribution of vertical components of a leakage magnetic field on the surface of a magnetic pattern based on a magneto-resistance (MR) component. According to the technical scheme of the utility model, due to the adoption of the magnetic head, magnetic patterns made of soft magnetic materials or hard magnetic materials can be effectively detected. By means of the horizontal excitation structure, soft magnetic materials are magnetized in an in-plane manner, so that a specific leakage magnetic field can be generated on the surface of a magnetic pattern. Based on the MR component of a Wheatstone bridge structure, the vertical components of a specific leakage magnetic field can be effectively detected. Therefore, the features of magnetic patterns made of soft magnetic materials or hard magnetic materials can be effectively detected.
Description
Technical field
The utility model relates to a kind of magnetic head based on magneto-resistor technology for detection magnetic pattern thereon Surface field.
Background technology
In banknote magnetic anti-counterfeit field, mainly use now audio head technology, magnetoresistive head technology and giant magnetoresistance effect technology on the market; In the bill anti-counterfeit field, be mainly the audio head technology.
The audio head technology: the soft magnetic materials such as this utilization permalloy are made into the ring texture with a slit, winding around on the ring texture.When the air gap of this ring texture during fast by magnetic pattern thereon surperficial, based on Faraday's electromagnetic induction law, coil inside produces induction current.Obtain the variation of magnetic pattern thereon Surface field by detecting faradic variation.The major defect of this technology is: 1. be adapted to detect the surface leakage magnetic field of hard magnetic material, need to add external drive magnetic field when detecting soft magnetic material, but this external drive magnetic field affected the sensitivity of this magnetic head to a great extent; 2. make in the situation of multichannel head, the consistance of the sensitivity of each road magnetic head is very difficult to guarantee, has reduced the yield rate of producing, and has increased the production cost of product; 3. this magnetic head has the ability that very low anti-external magnetic field disturbs, just require under the working environment of complexity, various interference sources to be carried out necessary shielding processing, increase on the one hand the cost of subsequent applications product, also increased on the other hand the design difficulty of subsequent applications product; 4. the output amplitude of signal and head relative are relevant in the relative velocity of detected magnetic pattern thereon, have increased difficulty for the quantitative test of signal; 5. really exist in some magnetic fields, but in the little situation of the difference on the space, the actual output of magnetic head is very little, may produce the undetected of magnetic information.
Magnetoresistive head technology: the magnetic resistance materials such as this utilization InSb, use two magnetic resistance resistance to form a Hui Sitong half-bridge, two magnetic resistance planar have the position difference on the space, detect the magnetic field gradient on magnetic pattern thereon surface by the difference that detects magnetic field on two magnetic resistance.Some shortcomings that this technology exists: 1. this technology must add in the vertical direction of element a bias magnetic field, magnetoresistive element could be worked, simultaneously, owing to needing perpendicular magnetization soft magnetism figure, needed magnetic field, in general is larger, and the very ferromagnetic permanent magnet of generation needs in this magnetic field produces to reduce the decay of magnetic, but the certainty of magnetic decay causes the sensitivity of magnetic resistance to change, that is to say the increase along with the time, the sensitivity meeting of magnetic head changes.2. the remolding sensitivity of magnetoresistive element is lower, general scope at 0.2 mV/V/Gs –, 1 mV/V/G, this just requires in the situation that measure low-intensity magnetic field (magnetic field intensity of the soft magnetism information on the banknote is generally all lower), and the enlargement factor of follow-up signal treatment circuit is very high.3. the noise of magnetoresistive element is larger, when detecting the low-intensity magnetic field signal, needs comparatively complicated frequency locking amplifying technique, and the frequency of the field signal that can detect is subject to certain limitation.4. owing to being to have adopted half-bridge structure, limited in one's ability for power-supply fluctuation and coupled outside Anti-jamming of signal, just require under the working environment of complexity, various interference sources to be carried out necessary shielding processing, increase on the one hand the cost of subsequent applications product, also increased on the other hand the design difficulty of subsequent applications product.5. in the design of multichannel head, be difficult to ensure the consistance of the sensitivity of each road magnetic head of card, reduced the yield rate of producing, increased the production cost of product.6. owing to having adopted the design of gradiometer, the spatial gradient of the vertical component in magnetic field can only be identified, the actual distribution in magnetic field can not be intuitively measured, really exist in some magnetic fields, but in the little situation of the difference on the space, the actual output of magnetic head is very little, may produce the undetected of magnetic information.
Giant magnetoresistance effect (GMR) technology: this technology can adopt the thin-film technique preparation, and sensitive direction is in pellicular front.Realization based on the magnetic head of this technology mainly contains dual mode: a kind of is at two GMR resistance of substrate preparation, the sensitive direction of these two GMR resistance can be consistent, also can be reverse, these two GMR resistance be connected into the form of Hui Sitong half-bridge.The plane of two GMR resistance placements is parallel plane with magnetic pattern thereon place to be detected, and simultaneously, the direction that the relative position of two GMR resistance placements can be and the checking magnetic pattern thereon is advanced is parallel, also can be the perpendicular direction of advancing with magnetic pattern thereon.This dual mode all is to detect the Grad on two GMR resistor chain column directions in face of component in the face of magnetic pattern thereon surface leakage field.The advantage of this technology is, owing to having adopted thin-film technique, the conformity of production ratio of product to be easier to guarantee.The shortcoming of this technology is: 1. because the mode that has adopted gradient to detect, can not directly measure the actual distribution in magnetic field, really exist in some magnetic fields, but in the little situation of the difference on the space, the actual output of magnetic head is very little, may produce the undetected of magnetic information; 2. owing to being to have adopted half-bridge structure, limited in one's ability for power-supply fluctuation and coupled outside Anti-jamming of signal, just require under the working environment of complexity, various interference sources to be carried out necessary shielding processing, increase on the one hand the cost of subsequent applications product, also increased on the other hand the design difficulty of subsequent applications product.
The utility model content
The utility model purpose is to provide the magnetic head based on magneto-resistor technology for detection soft magnetism figure that can accurately measure the actual size of magnetic field vertical component for the defective that prior art exists, and its quantitative test for magnetic pattern thereon surface leakage field provides possibility.
The utility model for achieving the above object, adopt following technical scheme: a kind of magnetic head based on magneto-resistor technology for detection magnetic pattern thereon Surface field, comprise support and the pcb board that is arranged on the support, also comprise horizontal excitation structure, it is for generation of a magnetic field that is parallel to head surface; With the magnetic field detection parts based on magneto-resistor MR element, it is for detection of the distribution situation of the vertical component in magnetic pattern thereon surface leakage magnetic field.
Further, described horizontal excitation structure is the two magnetized permanent magnets of level in front and back are placed on described magnetic field detection parts along direction of magnetization front and back position.
Further, described horizontal excitation structure is the permanent magnet of two perpendicular magnetizations in front and back oppositely is placed on the front and back of described magnetic field detection parts along the vertical direction of direction of magnetization symmetric position.
Further, described horizontal excitation structure is front end/rear end that a magnetized permanent magnet of level is placed on described magnetic field detection parts, and another piece soft magnetic material block is placed on the rear end/front position of described magnetic field detection parts.
Further, described magnetic field detection parts are the Hui Sitong bridge architecture that is comprised of a plurality of magneto-resistor MR elements.
Further, described favour stone bridge architecture is Hui Sitong full bridge structure or Hui Sitong half-bridge structure.
Further, when described favour stone bridge architecture was the Hui Sitong full bridge structure, two magneto-resistor MR elements wherein were near the surface of magnetic head, and two other magneto-resistor MR element is away from the surface of magnetic head; When described favour stone bridge architecture was the Hui Sitong half-bridge structure, one of them magneto-resistor MR element was near the surface of magnetic head, and another one magneto-resistor MR element is away from the surface of magnetic head.
Further, the sensitive direction of described magneto-resistor MR element is unanimously perpendicular to the surface of magnetic head.
Further, described magneto-resistor MR element is at least a kind of in anisotropic magnetoresistance AMR element or giant magnetoresistance GMR element or the tunneling magnetic resistance TMR element.
The beneficial effects of the utility model: (1) the utility model adopts the magneto-resistor technology, has high magnetic field sensitivity, so that the follow-up signal treatment circuit is relatively simple.Adopt horizontal excitation mode, can directly add excitation field in the position of detecting, because magnetic pattern thereon is laminar in macroscopic view, its magnetic easy magnetizing axis in the horizontal direction, needed excitation field is less, therefore producing the needed permanent magnet in this magnetic field can be cheap Ferrite Material, when effectively reducing production costs, has increased the thermal stability of excitation field.
(2) the utility model can effectively detect the magnetic pattern thereon that the soft magnetic property material forms.By horizontal excitation structure soft magnetic material is magnetized in face, produce specific stray field on the magnetic pattern thereon surface; Vertical direction detects the Hui Sitong bridge arrangement that forms with the MR element, this structure can effectively detect the size of vertical component of the surperficial leakage field of magnetic pattern thereon, can truly reflect the truth in magnetic pattern thereon surface leakage magnetic field, thereby effectively detect the feature of the magnetic pattern thereon of soft magnetic material composition; For the quantitative test of magnetic pattern thereon surface leakage field provides possibility.But stopped really to exist in the less situation of the spatial gradient of magnetic field in face in stray field the situation that existing magnetic head may be undetected.
(3) the utility model adopts the Hui Sitong full bridge structure, and the sensitive direction of four magneto-resistors wherein is identical, therefore has extraordinary anti-external electromagnetic field interference performance.
Description of drawings
The schematic diagram of Fig. 1 the first excitation structure of the present utility model;
The schematic diagram of Fig. 2 the second excitation structure of the present utility model;
The schematic diagram of Fig. 3 the third excitation structure of the present utility model;
Fig. 4 favour stone of the present utility model bridge architecture schematic diagram;
The connection diagram of the three kinds of bridge circuits of Hui Sitong bridge architecture in Fig. 5 the utility model;
The scatter chart in Fig. 6 magnetic field of the present utility model;
Fig. 7 MR element of the present utility model is in the scatter chart in the magnetic field.
Embodiment
Fig. 1 is a kind of magnetic head based on magneto-resistor technology for detection magnetic pattern thereon Surface field to shown in Figure 3, comprises support 1 and the pcb board 5 that is arranged on the support, also comprises horizontal excitation structure, and it is for generation of a magnetic field that is parallel to head surface; The magnetic pattern thereon that soft magnetic material consists of can be magnetized in this magnetic field, after this magnetic pattern thereon is magnetized, produces specific Magnetic fluxleakage distribution on its surface, and the numerical value in this magnetic field is along with the increase of the distance on distance magnetic pattern thereon surface sharply reduces; With the magnetic field detection parts based on magneto-resistor MR element, it is for detection of the distribution situation of the vertical component in magnetic pattern thereon surface leakage magnetic field.
This excitation structure can have the mode of a variety of realizations:
Among Fig. 1, described excitation structure is that the magnetized permanent magnet 20 of two levels in front and back, 21 is placed on the front and back position of described magnetic field detection parts 4 along direction of magnetization.
Among Fig. 2, described excitation structure is that the permanent magnet 20,21 of two perpendicular magnetizations in front and back oppositely is placed on the symmetric position of the front and back of described magnetic field detection parts 4 along the vertical direction of direction of magnetization.
Among Fig. 3, described excitation structure is front end/rear end that a magnetized permanent magnet 21 of level is placed on described magnetic field detection parts 4, and another piece soft magnetic material block 7 is placed on the rear end/front position of described magnetic field detection parts 4.In addition, also have a variety of methods that obtain the horizontal direction excitation field.
Shown in Figure 4, the magnetic field detection parts are the Hui Sitong bridge architecture that is comprised of a plurality of magneto-resistor MR elements.The sensitive direction of described magneto-resistor MR element wherein is unanimously perpendicular to the surface of magnetic head.Wherein, described magneto-resistor MR element is at least a kind of in anisotropic magnetoresistance AMR element or giant magnetoresistance GMR element or the tunneling magnetic resistance TMR element.When described favour stone bridge architecture was the Hui Sitong full bridge structure, two magneto-resistor MR elements wherein were near the surface of magnetic head, and two other magneto-resistor MR element is away from the surface of magnetic head; When described favour stone bridge architecture was the Hui Sitong half-bridge structure, one of them magneto-resistor MR element was near the surface of magnetic head, and another one magneto-resistor MR element is away from the surface of magnetic head.
Fig. 5 is concrete embodiment: the situation of a magneto-resistor R1/R2(half-bridge) or the situation of two magneto-resistor R1 and R2(full-bridge) near the surface of magnetic head; The situation of a magneto-resistor R3/R4(half-bridge in addition) or the situation of two magneto-resistor R3 and R4(full-bridge) away from the surface of magnetic head.These magneto-resistors MR element is according to the structure of Hui Sitong full-bridge or Hui Sitong half-bridge link together (seeing the method for attachment of a among Fig. 5, b, three kinds of bridge circuits of c).Because the magnetic field amplitude that the magnetic field amplitude of experiencing near the magneto-resistor of head surface arrives much larger than the resistor senses away from head surface, and the latter's magnetic field is close to zero, so these magnetic field detection parts 4 can detect the true distribution situation of the vertical component in magnetic pattern thereon surface leakage magnetic field.
Shown in Figure 6, the resistance of magneto-resistor MR element has two types along with the change curve of external magnetic field.A kind of is external magnetic field during less than saturation magnetic field, and the resistance of magneto-resistor MR element is referred to as " linear magnetoresistance MR element " along with the external magnetic field lines variation; Another is external magnetic field during less than saturation magnetic field, the resistance of magneto-resistor MR element along with the change curve of external magnetic field for falling " V " type curve, be referred to as " V-type magneto-resistor MR element ".Because the impact of the error of the relative position of magnet and magneto-resistor MR element and the factors such as mismachining tolerance of magnet, on the sensitive direction of magneto-resistor MR element, may have a certain size magnetic field, but this magnetic field all can be controlled in the MR element operation interval within.For linear magnetoresistance MR element, use permanent magnet with respect to the location arrangements of magneto-resistor MR element symmetry, can be so that close zero magnetic field (seeing the scatter chart 6a in magnetic field) of the operation interval of magneto-resistor MR element; For V-type magneto-resistor MR element, can suitably adjust permanent magnet with respect to the asymmetry of the position of magneto-resistor MR element, the operation interval of adjusting magneto-resistor MR is positioned at positive flux field interval or negative fluxfield interval (seeing the scatter chart 6b in magnetic field).
Shown in Figure 7, the distribution of the two kind components of magneto-resistor MR element in magnetic field: Fig. 7 a is that linear magnetoresistance MR element is in the distribution situation in the magnetic field; Fig. 7 b is that V-type magneto-resistor MR element is in the distribution situation in the magnetic field.
The above only is preferred embodiment of the present utility model, and is in order to limit the utility model, not all within spirit of the present utility model and principle, any modification of doing, is equal to replacement, improvement etc., all should be included within the protection domain of the present utility model.
Claims (9)
1. the magnetic head based on magneto-resistor technology for detection magnetic pattern thereon Surface field comprises support and the pcb board that is arranged on the support, it is characterized in that, also comprise horizontal excitation structure, it is for generation of a magnetic field that is parallel to head surface; With the magnetic field detection parts based on magneto-resistor MR element, it is for detection of the distribution situation of the vertical component in magnetic pattern thereon surface leakage magnetic field.
2. a kind of magnetic head based on magneto-resistor technology for detection magnetic pattern thereon Surface field as claimed in claim 1, it is characterized in that, described horizontal excitation structure is the two magnetized permanent magnets of level in front and back are placed on described magnetic field detection parts along direction of magnetization front and back position.
3. a kind of magnetic head based on magneto-resistor technology for detection magnetic pattern thereon Surface field as claimed in claim 1, it is characterized in that, described horizontal excitation structure is the permanent magnet of two perpendicular magnetizations in front and back oppositely is placed on the front and back of described magnetic field detection parts along the vertical direction of direction of magnetization symmetric position.
4. a kind of magnetic head based on magneto-resistor technology for detection magnetic pattern thereon Surface field as claimed in claim 1, it is characterized in that, described horizontal excitation structure is front end/rear end that a magnetized permanent magnet of level is placed on described magnetic field detection parts, and another piece soft magnetic material block is placed on the rear end/front position of described magnetic field detection parts.
5. such as each described a kind of magnetic head based on magneto-resistor technology for detection magnetic pattern thereon Surface field of claim 1 to 4, it is characterized in that, described magnetic field detection parts are the Hui Sitong bridge architecture that is comprised of a plurality of magneto-resistor MR elements.
6. a kind of magnetic head based on magneto-resistor technology for detection magnetic pattern thereon Surface field as claimed in claim 5 is characterized in that, described favour stone bridge architecture is Hui Sitong full bridge structure or Hui Sitong half-bridge structure.
7. a kind of magnetic head based on magneto-resistor technology for detection magnetic pattern thereon Surface field as claimed in claim 6, it is characterized in that, when described favour stone bridge architecture is the Hui Sitong full bridge structure, two magneto-resistor MR elements wherein are near the surface of magnetic head, and two other magneto-resistor MR element is away from the surface of magnetic head; When described favour stone bridge architecture was the Hui Sitong half-bridge structure, one of them magneto-resistor MR element was near the surface of magnetic head, and another one magneto-resistor MR element is away from the surface of magnetic head.
8. a kind of magnetic head based on magneto-resistor technology for detection magnetic pattern thereon Surface field as claimed in claim 7 is characterized in that, the sensitive direction of described magneto-resistor MR element is unanimously perpendicular to the surface of magnetic head.
9. a kind of magnetic head based on magneto-resistor technology for detection magnetic pattern thereon Surface field as claimed in claim 8, it is characterized in that, described magneto-resistor MR element is at least a kind of in anisotropic magnetoresistance AMR element or giant magnetoresistance GMR element or the tunneling magnetic resistance TMR element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320191112 CN203204700U (en) | 2013-04-16 | 2013-04-16 | Magnetic head used for detecting magnetic field on surface of magnetic pattern based on magneto-resistance technology |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320191112 CN203204700U (en) | 2013-04-16 | 2013-04-16 | Magnetic head used for detecting magnetic field on surface of magnetic pattern based on magneto-resistance technology |
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| CN203204700U true CN203204700U (en) | 2013-09-18 |
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| CN 201320191112 Withdrawn - After Issue CN203204700U (en) | 2013-04-16 | 2013-04-16 | Magnetic head used for detecting magnetic field on surface of magnetic pattern based on magneto-resistance technology |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103226865A (en) * | 2013-04-16 | 2013-07-31 | 白建民 | Magnetic head for detecting surface magnetic field of magnetic graph based on magnetoresistive technology |
| CN107607612A (en) * | 2017-08-11 | 2018-01-19 | 清华大学 | The defects of vertical component based on magnetic leakage signal outline identification method and device |
-
2013
- 2013-04-16 CN CN 201320191112 patent/CN203204700U/en not_active Withdrawn - After Issue
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103226865A (en) * | 2013-04-16 | 2013-07-31 | 白建民 | Magnetic head for detecting surface magnetic field of magnetic graph based on magnetoresistive technology |
| CN103226865B (en) * | 2013-04-16 | 2016-05-25 | 无锡乐尔科技有限公司 | A kind of magnetic head based on magneto-resistor technology for detection magnetic pattern thereon Surface field |
| CN107607612A (en) * | 2017-08-11 | 2018-01-19 | 清华大学 | The defects of vertical component based on magnetic leakage signal outline identification method and device |
| CN107607612B (en) * | 2017-08-11 | 2019-11-22 | 清华大学 | The defect profile recognition methods of vertical component based on magnetic leakage signal and device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20130918 Effective date of abandoning: 20160525 |
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| C25 | Abandonment of patent right or utility model to avoid double patenting |