CN203038357U - Magnetically-biased currency-detection magnetic head with sensitive direction parallel to detection surface - Google Patents
Magnetically-biased currency-detection magnetic head with sensitive direction parallel to detection surface Download PDFInfo
- Publication number
- CN203038357U CN203038357U CN2012205645396U CN201220564539U CN203038357U CN 203038357 U CN203038357 U CN 203038357U CN 2012205645396 U CN2012205645396 U CN 2012205645396U CN 201220564539 U CN201220564539 U CN 201220564539U CN 203038357 U CN203038357 U CN 203038357U
- Authority
- CN
- China
- Prior art keywords
- magnetic head
- currency examine
- magnetic
- currency
- bias unit
- 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.)
- Expired - Lifetime
Links
Images
Landscapes
- Measuring Magnetic Variables (AREA)
Abstract
The utility model relates to a magnetically-biased currency-detection magnetic head with the sensitive direction parallel to the detection surface. The currency-detection magnetic head comprises a magnetoresistive sensor chip, a flexible printed circuit board coupled with the magnetoresistive sensor chip and a magnetic bias unit. The magnetoresistive sensor chip includes a circuit containing a magneto-sensitive element, the sensitive direction of the magneto-sensitive element is parallel to the detection surface of the currency-detection magnetic head, the magnetic bias unit has a concave structure and is separated from the magnetoresistive sensor chip in placement at one side, far away from the detection surface of the currency-detection magnetic head, of the magnetoresistive sensor chip, and the concave structure faces towards the magnetoresistive sensor chip. The currency-detection magnetic head of the utility model has higher sensitivity and signal-to-noise ratio.
Description
Technical field
The utility model relates to the magnetoresistive transducer technical field, particularly a kind of magnetic resistance currency examine magnetic head.
Background technology
In the daily life, the application of currency examine magnetic head is very extensive, for example automatic vending machine, paper money counter, and the bank note inspection machine etc.Usually, the magnetic of bank note very a little less than, therefore, the currency examine magnetic head that is used for identification bank note magnetic need have the characteristic of high sensitivity, low noise and high s/n ratio.
Fig. 1 shows a kind of currency examine magnetic head of prior art, and what the sensor element in this currency examine magnetic head detected is the magnetic-field component vertical with the magnetic head detection faces, and this magnetic field is produced by the magnetic ink on the bank note.Generally, this sensor element material therefor is indium antimonide.The currency examine magnetic head that is made of this sensor element has following shortcoming:
(1) sensitivity of indium antimonide Hall unit and signal to noise ratio (S/N ratio) are very low, cause the sensitivity of this kind currency examine magnetic head and signal to noise ratio (S/N ratio) very low;
(2) indium antimonide sensor and be subjected to Temperature Influence very obvious needs complicated temperature-compensation circuit;
(3) indium antimonide sensor intrinsic noise is bigger, therefore needs the magnetic bias element that very big offset signal is provided, and to improve signal to noise ratio (S/N ratio), causes the volume of magnetic bias element bigger thus, and then causes currency examine magnetic head volume bigger;
(4) have a planar poles of magnetic bias element near the magnetic head detection faces, this magnetic pole produces the magnetic-field component parallel with detection faces.Because the existence of this magnetic-field component causes being difficult to accurately measuring the size that testee produces magnetic field.
Therefore, need a kind of currency examine head that can accurately measure testee magnetic field size.
The utility model content
In order to solve the above problems, the utility model provides a kind of magnetic resistance currency examine magnetic head.Used magnetoresistive transducer can be measured the magnetic-field component that is parallel to detection faces that testee produces in the utility model, and magnetoresistive transducer can be the tunnel magnetoresistive sensor, or giant magneto-resistance sensor, or anisotropic magnetoresistive sensor etc.
According to an aspect of the present utility model, a kind of currency examine magnetic head is provided, this currency examine magnetic head comprises the magnetoresistive transducer chip, with flexible printed circuit board and the magnetic bias unit of this magnetoresistive transducer chip coupling,
Described magnetoresistive transducer chip comprises the circuit with magneto sensor, and the sensitive direction of described magneto sensor is parallel to the detection faces of described currency examine magnetic head,
Described magnetic bias unit has sunk structure and placed apart away from currency examine magnetic head detection faces one side and described magnetoresistive transducer chip at described magnetoresistive transducer chip, and this sunk structure is towards described magnetoresistive transducer chip.
Preferably, described magnetic bias unit comprises having perpendicular to the rectangular recess of detection faces or the rectangular permanent magnet of pit.
Preferably, described magnetic bias unit comprises the pole piece that surface that permanent magnetism rectangular parallelepiped and high permeability magnetic material constitute has rectangular depression.
Preferably, described magnetic bias unit comprises the rectangular ring pole piece that permanent magnetism rectangular parallelepiped and high permeability magnetic material constitute.
Preferably, the surveyed area of described currency examine magnetic head be positioned at described magnetic bias element sunk structure directly over.
Preferably, the magnetic field that is arranged such that its generation, described magnetic bias unit at the component of described magneto sensor sensitive direction less than 25 Gausses.
Preferably, this currency examine magnetic head comprises that further the currency examine magnetic head input and output that are connected with flexible PCB draw pin.
Preferably, described magneto sensor is tunnel magnetoresistive TMR element, giant magnetoresistance GMR element or anisotropic magnetoresistive AMR element.
Preferably, described magneto sensor constitutes single armed structure or half-bridge structure or full bridge structure for series connection and/or the TMR element that is connected in parallel or series connection and/or the GMR element that is connected in parallel or series connection and/or the AMR element that is connected in parallel.
Preferably, described magnetoresistive transducer chip is TMR magneto sensor chip, the magneto sensor sensor chip that half-bridge connects, perhaps the magneto sensor sensor chip of full-bridge connection that is connected in series.
Preferably, described magnetoresistive transducer chip is single armed sensor chip, half-bridge sensor chip, perhaps full-bridge sensors chip.
Preferably, this magnetic head further comprises the metal shell that holds described magnetoresistive transducer chip and described magnetic bias unit, and described metal shell is provided with earth terminal.
Preferably, be filled with in the described metal shell for injection molding body fixing and that isolate.
Preferably, this magnetic head further comprises the metal shell that holds described magnetoresistive transducer chip and described magnetic bias unit, and this shell has opening at magnetic head detection faces opposite side.
The utlity model has following beneficial effect:
(1) currency examine magnetic head described in the utility model both had been applicable to the bank note that identification is made by retentive material, was applicable to the bank note that identification is made by soft magnetic material again;
(2) currency examine magnetic head described in the utility model adopts the magnetoresistive transducer chip that comprises as magneto sensors such as tunnel magnetoresistive TMR element, giant magnetoresistance GMR element or anisotropic magnetoresistive AMR elements, compare with indium antimonide Hall unit, sensitivity and the signal to noise ratio (S/N ratio) of above-mentioned magneto sensor are higher, and therefore currency examine magnetic head of the present utility model has higher sensitivity and signal to noise ratio (S/N ratio);
(3) because the manufacture craft of above-mentioned magneto sensor is simpler, and be not subject to environment temperature and stress influence, the yield rate height, therefore simpler according to the processing technology of currency examine magnetic head of the present utility model, cost is lower;
(4) form depression by the magnetic bias element with the currency examine magnetic head, it is very little or level off to zero at the component of above-mentioned magneto sensor sensitive direction to have magnetic field that the magnetic bias element of depression produces, make magneto sensor can be operated in linear zone, thereby can guarantee that the currency examine magnetic head can operate as normal;
(5) because the sensor chip of currency examine magnetic head adopts bridge architecture, make the currency examine magnetic head can effectively suppress the interference from the common mode magnetic field outside the described currency examine magnetic head;
(6) currency examine magnetic head of the present utility model both can be used for cash inspecting machine, can be used for cashier's machine again;
(7) adopt flexible circuit board connection printed-wiring board (PWB) and output to draw pin according to currency examine magnetic head of the present utility model, and flexible circuit board can not produce restriction to the profile of permanent magnet, be conducive to the design of permanent magnet.
Description of drawings
Fig. 1 is the synoptic diagram of the currency examine magnetic head of prior art comparative example 1;
Fig. 2 (A) is the magnetic line of force distribution plan in the magnetic field that the rectangle permanent magnet produces in the magnetic head shown in Figure 1;
Fig. 2 (B) is the magnetic field distribution that the rectangle permanent magnet produces in the magnetic head shown in Figure 1;
Fig. 3 (A) is the magnetic line of force distribution plan in the magnetic field that the rectangle permanent magnet produces in the magnetic head of prior art comparative example 2;
Fig. 3 (B) is the magnetic field distribution that the rectangle permanent magnet produces in the magnetic head of prior art comparative example 2;
Fig. 4 is the synoptic diagram according to the currency examine magnetic head of the utility model embodiment;
Fig. 5 illustrates the schematic top plan view according to the currency examine magnetic head of the utility model embodiment;
Fig. 6 (A) is the magnetic line of force distribution plan according to the magnetic field of magnetic bias unit generation in the magnetic head of the utility model example 1;
Fig. 6 (B) is the magnetic field distribution that produces according to magnetic bias unit in the magnetic head of the utility model example 1;
Fig. 7 (A) is the magnetic line of force distribution plan in the magnetic field that the magnetic bias unit produces in the magnetic head of example 2;
Fig. 7 (B) is the magnetic field distribution that the magnetic bias unit produces in the magnetic head of example 2;
Fig. 7 (C) is the skeleton view of pole piece in the magnetic bias unit of example 2;
Fig. 8 (A) is the magnetic line of force distribution plan in the magnetic field that the magnetic bias unit produces in the magnetic head of example 3;
Fig. 8 (B) is the magnetic field distribution that the magnetic bias unit produces in the magnetic head of example 3;
Fig. 8 (C) is the skeleton view of magnetic bias unit in the magnetic head of example 3.
Embodiment
Below with reference to the accompanying drawings and in conjunction with the embodiments, describe the technical solution of the utility model in detail.In embodiment, similar Reference numeral is represented similar feature or element.
Comparative example 1
Fig. 1 illustrates the synoptic diagram of the currency examine magnetic head of comparative example 1.This currency examine magnetic head comprises that sensor chip 11, printed-wiring board (PWB) (PCB) 12, input and output draw pin 13, metal shell 14, permanent magnet 15 and injection molding body (not shown).On the face away from detection faces of metal shell 14 opening is arranged, be used for assembling and input and output and draw drawing of pin.Sensor chip 11 is installed near the detection faces of metal shell 14, and its magnetosensitive direction is perpendicular to the magnetic head detection faces.Sensor chip 11 and permanent magnet 15 are located at the both sides of printed-wiring board (PWB) 12 respectively.The magnetizing direction of permanent magnet 15 as shown in Figure 1.Directly do not contact between printed-wiring board (PWB) 12 and the permanent magnet 15.The input end of sensor chip 11 and output terminal respectively with printed-wiring board (PWB) 12 on respective terminal welding, make printed-wiring board (PWB) 12 can support and fixation of sensor chip 11.The respective terminal welding of an end and the printed-wiring board (PWB) 12 of pin 13 is drawn in input and output, makes input and output draw input end and the output terminal conducting of pin 13 and sensor chip 11.Input and output are drawn the other end of pin 13 as the output terminal of currency examine magnetic head.Sensor chip 11 adopts indium antimonide Hall unit, and the sensitive direction 17 of indium antimonide Hall unit is perpendicular to the detection faces of magnetic head.Metal shell 14 is provided with ground connection and draws pin 16.Be provided with ground connection and draw the metal shell 14 of pin 16 and be used for shielding from the electromagnetic interference (EMI) outside the metal shell 14, and eliminate static.The shape of permanent magnet 15 can be rectangular parallelepiped.The shape and size of injection molding body are mated with the shape and size of metal shell 14, printed-wiring board (PWB) 12 and permanent magnet 15 respectively, are used for fixing metal shell 14, printed-wiring board (PWB) 12 and permanent magnet 15, and realize the electrical isolation of printed-wiring board (PWB) 12 and permanent magnet 15.
The sensor chip of currency examine magnetic head adopts indium antimonide Hall unit in this comparative example 1, and the sensitivity of described currency examine magnetic head and signal to noise ratio (S/N ratio) are very low.Since the complex manufacturing technology of indium antimonide Hall unit, and be subjected to temperature and stress influence very obvious, and yield rate is low, causes the processing technology complexity of the currency examine magnetic head of comparative example, the cost height.On the other hand, directly be fixed on the printed-wiring board (PWB) because an end of pin is drawn in the output of the currency examine magnetic head of comparative example, and output draws pin and can not directly pass permanent magnet, therefore the size of permanent magnet has been limited in the output position of drawing pin, increases the difficulty of design.In addition, because the permanent magnet of the currency examine magnetic head of comparative example 1 is rectangular parallelepiped, when sensor chip adopts the MTJ element, the magnetic field that the rectangle permanent magnet produces is very big along the component of MTJ element sensitive direction, cause the working point of MTJ element to depart from its linear work district, even the resistance that causes the MTJ element reaches capacity to the response in magnetic field, thereby influences the performance of currency examine magnetic head, even causes the currency examine magnetic head can't operate as normal.
Fig. 2 (A) is in the currency examine magnetic head shown in Figure 1, the magnetic line of force distribution plan in the magnetic field that rectangular magnet produces.Have the direction of magnetization of permanent magnet 15 of rectangular cross section structure among the figure perpendicular to detection faces 40, detection faces is with " AA " among figure expression.Magnetoresistive sensor element 41 is positioned at the below of detection faces 40, and " BB " direction in figure is placed.The magnetic line of force in the magnetic field that permanent magnet 15 produces is shown in the fine line 23 among the figure.Fig. 2 (B) has showed that magnetic field that permanent magnet 15 produces is parallel to the component 28 of detection faces direction at the detection faces place and perpendicular to the component 27 of detection faces direction, transverse axis 29 is illustrated in the side-play amount of position on " AA " direction.In traditional Hall effect currency examine magnetic head, only detection of vertical is in the magnetic-field component 27 of detection faces direction for sensor, and the magnetic-field component 28 that therefore is parallel to the detection faces direction can not produce any influence to the work of currency examine magnetic head.
If when the induction direction of magnetoresistive transducer is parallel to detection faces 40, must improve lift magnet, to reduce the magnetic field that is parallel to detection faces that permanent magnet produces to the influence of sensor sensing signal.
Prior art comparative example 2
The volume ratio that increases lift magnet and sensor element is a kind of effective ways that address the above problem.Fig. 3 (A) and 3 (B) are respectively magnetic line of force distribution plan and the magnetic field distribution figure in the magnetic field that the rectangle permanent magnet produces in the magnetic head of prior art comparative example 2.Comparison diagram 3(A) and Fig. 2 (A) as can be seen, lift magnet 35 proximity sense elements 41 one side has the area of remarkable increase.As can be seen, the direction of magnetization 21 of permanent magnet 35 is perpendicular to detection faces 40 from Fig. 3 (A), and the detection side is to being " AA " among the figure.Magnetoresistive sensor element 41 is positioned at the below of detection faces 40, and " BB " direction in figure is placed.The magnetic line of force in the magnetic field that permanent magnet 35 produces is shown in the solid line 23 among the figure.Fig. 3 (B) has showed that magnetic field that permanent magnet 35 produces is parallel to the component 28 of detection faces direction at the detection faces place and perpendicular to the component 27 of detection faces direction, transverse axis 29 is illustrated in the side-play amount of position on " AA " direction.From Fig. 3 (B) as can be seen, comparative example 2 magnetic-field component 28 that is parallel to the detection faces direction is significantly less than the magnetic-field component that is parallel to the detection faces direction of comparative example 1 among Fig. 2 (B).
But in the comparative example 2, bigger permanent magnet volume can increase the volume of currency examine magnetic head, and then increases its mounting hardness in cash inspecting machine.Further, the volume that increases permanent magnet and magnetic head means the increase of cost of products, and then increases the cost of cash inspecting machine.
Preferred embodiment of the present utility model
Fig. 4 illustrates the currency examine magnetic head synoptic diagram according to the utility model embodiment.Comprise that according to magnetic resistance currency examine magnetic head of the present utility model pin 43, metal shell 44 are drawn in magnetoresistive transducer chip 41, printed-wiring board (PWB) 42, input and output, magnetic bias unit 45 with sunk structure for example has permanent magnet, flexible circuit board (FPC) 46, first injection molding body 47 and second injection molding body 50 of depression, and has detection faces 40.This magnetic bias unit with depression for example is the permanent magnet that has rectangular recess in a side, or has the permanent magnet of rectangle pit in a side.Metal shell 44 adopts non magnetic high-abrasive material, and it has opening in the side away from detection faces 40.Magnetoresistive transducer chip 41 is installed near detection faces 40 in metal shell 44, and the sensitive direction of magneto sensor is parallel with the detection faces of currency examine magnetic head in the chip.Detection faces 40 side outer surface of outer cover are less than or equal to 0.2mm apart from the distance between the magnetoresistive transducer chip upper surface.Magnetoresistive transducer chip 41 and magnetic bias unit 45 lay respectively at the both sides of printed-wiring board (PWB) 42, and the sunk part of magnetic bias unit 45 is towards printed-wiring board (PWB) 42.The magnetizing direction of magnetic bias unit 45 is perpendicular to detection faces 40, as shown in Figure 4.Second injection molding body 50 for example between printed-wiring board (PWB) 42 and magnetic bias unit 45, is used for printed-wiring board (PWB) 42 and magnetic bias unit 45 are isolated.The input end of sensor chip 41 and output terminal respectively with printed-wiring board (PWB) 42 on respective terminal for example by being welded to connect, make printed-wiring board (PWB) 42 can support and fixation of sensor chip 41.First injection molding body 47 is positioned at a side opposite with sunk part of magnetic bias unit 45.It is fixing by first injection molding body 47 that pin 43 is drawn in input and output.One end of flexible circuit board 46 is electrically connected with the respective terminal of printed-wiring board (PWB) 42, and the other end of flexible circuit board 46 is electrically connected with the end that pin 43 is drawn in input and output, make input and output draw pin 43 respectively with input end and the output terminal conducting of sensor chip 41.Input and output are drawn the other end of pin 43 as the input/output terminal of currency examine magnetic head.Sensor chip 41 comprises a bridge circuit at least, and this bridge circuit comprises a brachium pontis at least, and preferably, each brachium pontis can comprise a for example tunnel magnetoresistive TMR element at least, the magneto sensor of giant magnetoresistance GMR element or anisotropic magnetoresistive AMR element.More preferably, the tunnel magnetoresistive TMR element that each brachium pontis can comprise series connection and/or be connected in parallel, the giant magnetoresistance GMR element of connecting and/or being connected in parallel, or the anisotropic magnetoresistive AMR element of connecting and/or being connected in parallel.In the present embodiment, sensor chip 41 has full bridge structure, and each brachium pontis in this full bridge structure comprises a magneto sensor at least.The sensitive direction 49 of magneto sensor is parallel with the detection faces of currency examine magnetic head, and the sensitive direction 49 of magneto sensor is vertical with the depression direction of magnetic bias unit 45.Preferably, metal shell 44 is provided with ground connection and draws pin 48, and the metal shell of ground connection is used for shielding from the electromagnetic interference (EMI) outside the metal shell 44, and is used for eliminating static.The shape and size of second injection molding body 50 are complementary with the shape and size of metal shell 44, printed-wiring board (PWB) 42 and magnetic bias unit 45 respectively, are used for printed-wiring board (PWB) 42 and magnetic bias unit 45 are fixed on metal shell 44.Preferably, first injection molding body 47 and second injection molding body 50 can fasten.
Fig. 5 illustrates the schematic top plan view according to the currency examine magnetic head of the magnetoresistive transducer chip that the utlity model has full bridge structure.As shown in the figure, magnetoresistive transducer chip 41 is positioned at the top of magnetic bias unit 45 sunk structures.Have a surveyed area 90 in magnetoresistive transducer chip 41, in this zone, the magnetic induction density that is parallel to detection faces 40 that permanent magnet 45 produces is less than 25 Gausses, and magnetic bias unit 45 can not be magnetized into each magneto sensor 91 in should the zone saturated.Therefore, can guarantee to be in the magneto sensor that its magnetosensitive direction is parallel to detection faces in the surveyed area and be operated in linear zone.In the direction that is parallel to magneto sensor sensitive direction 49, the range of size of surveyed area 90 for example is that 1mm is to 10mm.
When using magnetic resistance currency examine magnetic head, with the detection faces of bank note near described magnetic resistance currency examine magnetic head, and it is moved with respect to this detection faces, and sensor chip will detect the magnetic variation of bank note and draw the pin output correlation signal by output, thereby realizes the identification to bank note magnetic.
Both be applicable to the magnetic of the bank note that identification is made by retentive material according to the magnetic resistance currency examine magnetic head of the utility model preferred embodiment, be applicable to the magnetic of the bank note that identification is made by soft magnetic material again.Described magnetic resistance currency examine magnetic head preferably adopts its sensitive direction to be parallel to the magneto sensor of the detection faces of currency examine magnetic head, for example TMR element, giant magnetoresistance GMR element or anisotropic magnetoresistive AMR element.Compare with indium antimonide Hall unit, sensitivity and the signal to noise ratio (S/N ratio) of these magneto sensors are higher, and therefore sensitivity and the signal to noise ratio (S/N ratio) of described magnetic resistance currency examine magnetic head are higher.The manufacture craft of these magneto sensors is simpler, and is not subject to temperature and stress influence, the yield rate height, and therefore the processing technology of described magnetic resistance currency examine magnetic head is simpler, and cost is lower.Because described magnetic resistance currency examine magnetic head adopts flexible circuit board to connect printed-wiring board (PWB) and pin is drawn in input and output, and flexible circuit board can not produce restriction to the profile of permanent magnet, be conducive to the design of permanent magnet.Because the permanent magnet of magnetic resistance currency examine magnetic head has sunk structure, it is very little or level off to zero along the component of magneto sensor sensitive direction to have magnetic field that the permanent magnet of sunk structure produces, make magneto sensor in its linear work district, thereby can guarantee described magnetic resistance currency examine magnetic head operate as normal.Because the sensor chip of described magnetic resistance currency examine magnetic head adopts the magneto sensor of bridge circuit structure, makes described magnetic resistance currency examine magnetic head can effectively suppress the interference from the common mode magnetic field outside the described magnetic resistance currency examine magnetic head.Described magnetic resistance currency examine magnetic head both can be used for cash inspecting machine, can be used for cashier's machine again
Being used for realizing that the method for designing of above-mentioned magnetic bias unit 45 is more, for example can be aforesaid magnetic element with sunk structure, the combined element of the perhaps combined element of magnet-pole piece, or rectangular magnet.The magnetic bias unit of listed these structures all has the production of being easy to, lower-cost advantage.Respectively the various examples of magnetic bias unit are described in detail below with reference to accompanying drawings.
Example 1
The magnetic line of force distribution plan in the magnetic field that Fig. 6 (A) produces for the rectangle permanent magnet that has sunk structure in the magnetic head according to the utility model example 1.Shown in Fig. 6 (A), permanent magnet 55 has groove 52 on the surface near detection faces 40, and the depth of groove direction forms reeded surface perpendicular to permanent magnet 55.The direction of magnetization 51 of permanent magnet 55 is perpendicular to detection faces 40.In the center of detection faces 40, have magnetic field 53 that the permanent magnet 55 of groove 52 produces perpendicular to detection faces 40, therefore eliminated at for example horizontal component ofmagnetic field at TMR sensor chip 41 places.
Fig. 6 (B) is the magnetic field distribution figure along detection faces 40, wherein dotted line 57 is perpendicular to the magnetic field strength component of detection faces 40, fine line 58 is the magnetic field strength component that are parallel to detection faces 40, and the longitudinal axis 56 is magnetic induction density, and transverse axis is the distance apart from the skew of detection faces 40 central points.As can be seen from the figure, the magnetic field strength component that is parallel to detection faces 40 of groove 55 tops is less, and the numerical value of the magnetic field intensity of this direction is significantly less than the situation of the traditional structure among Fig. 2 and Fig. 3.
Be appreciated that the magnetic bias unit with sunk structure also can be the rectangle permanent magnet with pit.
Example 2
Fig. 7 (A) is the magnetic line of force distribution plan in the magnetic field that the magnetic bias element produces in the magnetic head of example 2.As Fig. 7 (A), the permanent magnet top with square-section 65 has covered a soft magnetic alloy sheet, is also referred to as " pole piece " 64, is used for adjusting the Distribution of Magnetic Field that is parallel to detection faces 40.Pole piece 64 is normally made by magnetically soft alloy, such as permalloy.The direction of magnetization 61 of permanent magnet 65 is perpendicular to detection faces 40, and the direction of magnetization of pole piece 64 is determined by the direction of magnetization of permanent magnet 65.The groove 62 of pole piece is used for reducing magnetic field in the magnetic field intensity that is parallel to detection faces 40 directions.
Fig. 7 (B) is that example 2 is along the magnetic field distribution figure of detection faces 40, wherein dotted line 67 is perpendicular to the magnetic field strength component of detection faces 40, fine line 68 is the magnetic field strength component that are parallel to detection faces 40, and the longitudinal axis 66 is magnetic induction density, and transverse axis is the offset distance along detection faces 40.As can be seen from the figure, the magnetic field intensity that is parallel to detection faces 40 above pole piece groove 64 is less, and the numerical value of the magnetic field intensity of this direction is significantly less than the situation of the traditional structure among Fig. 2 and Fig. 3.
Fig. 7 (C) is the skeleton view of example 2 pole pieces 64, and wherein groove structure 62 can be realized by methods such as die casting, punching press, cuttings.
Example 3
Fig. 8 (A) is the magnetic line of force distribution plan in the magnetic field that the magnetic bias element produces in the magnetic head of example 3.Shown in Fig. 8 (A), the permanent magnet top with square-section 75 has covered a soft magnetic alloy sheet, also is referred to as pole piece 74, is used for adjusting permanent magnet in the Distribution of Magnetic Field that is parallel to detection faces 40.Pole piece 74 is normally made by magnetically soft alloy, such as permalloy.The direction of magnetization 71 of permanent magnet 75 is perpendicular to detection faces 40, and the direction of magnetization of pole piece 74 is determined by the direction of magnetization of permanent magnet 75.Perforate 72 on the pole piece 74 is used for reducing being parallel to the intensity in the magnetic field of detection faces 40.
Fig. 8 (B) is the magnetic field distribution figure along detection faces 40, wherein dotted line 77 is perpendicular to the magnetic field strength component of detection faces 40, fine line 78 is the magnetic field strength component that are parallel to detection faces 40, and the longitudinal axis 76 is magnetic induction density, and transverse axis is the distance apart from detection faces 40 neutral point excursions.As can be seen from the figure, the magnetic field intensity that is parallel to detection faces 40 above pole piece 74 perforates is less, and the numerical value of the magnetic field intensity of this direction is significantly less than the situation of the traditional structure among Fig. 2 and Fig. 3.
Fig. 8 (C) is the skeleton view of example 3 pole pieces 64, and wherein the structure of perforate 72 can be by die casting, punching press, and methods such as cutting realize.
The above is preferred embodiment of the present utility model only, is not limited to the utility model, and for a person skilled in the art, the utility model can have various changes and variation.All within spirit of the present utility model and principle, any modification of doing, be equal to replacement, improvement etc., all should be included within the protection domain of the present utility model.
Claims (13)
1. a currency examine magnetic head comprises the magnetoresistive transducer chip, with flexible printed circuit board and the magnetic bias unit of this magnetoresistive transducer chip coupling,
It is characterized in that,
Described magnetoresistive transducer chip comprises the circuit with magneto sensor, and the sensitive direction of described magneto sensor is parallel to the detection faces of described currency examine magnetic head,
Described magnetic bias unit has sunk structure and placed apart away from currency examine magnetic head detection faces one side and described magnetoresistive transducer chip at described magnetoresistive transducer chip, and this sunk structure is towards described magnetoresistive transducer chip.
2. currency examine magnetic head as claimed in claim 1 is characterized in that, described magnetic bias unit comprises having perpendicular to the rectangular recess of detection faces or the rectangular permanent magnet of pit.
3. currency examine magnetic head as claimed in claim 1 is characterized in that, described magnetic bias unit comprises the pole piece that the surface of permanent magnetism rectangular parallelepiped and high permeability magnetic material formation has rectangular depression.
4. currency examine magnetic head as claimed in claim 1 is characterized in that, described magnetic bias unit comprises the rectangular ring pole piece that permanent magnetism rectangular parallelepiped and high permeability magnetic material constitute.
5. currency examine magnetic head as claimed in claim 1 is characterized in that, the surveyed area of described currency examine magnetic head be positioned at described magnetic bias element sunk structure directly over.
6. currency examine magnetic head as claimed in claim 1 is characterized in that, the magnetic field that described magnetic bias unit is arranged such that its generation at the component of described magneto sensor sensitive direction less than 25 Gausses.
7. currency examine magnetic head as claimed in claim 1 is characterized in that, this currency examine magnetic head comprises that further the currency examine magnetic head input and output that are connected with flexible PCB draw pin.
8. currency examine magnetic head as claimed in claim 1 is characterized in that, described magneto sensor is tunnel magnetoresistive TMR element, giant magnetoresistance GMR element or anisotropic magnetoresistive AMR element.
9. currency examine magnetic head as claimed in claim 1, it is characterized in that described magneto sensor constitutes single armed structure or half-bridge structure or full bridge structure for series connection and/or the TMR element that is connected in parallel, the GMR element of connecting and/or being connected in parallel or series connection and/or the AMR element that is connected in parallel.
10. currency examine magnetic head as claimed in claim 1 is characterized in that, described magnetoresistive transducer chip is single armed sensor chip, half-bridge sensor chip, perhaps full-bridge sensors chip.
11. currency examine magnetic head as claimed in claim 1 is characterized in that, this magnetic head further comprises the metal shell that holds described magnetoresistive transducer chip and described magnetic bias unit, and described metal shell is provided with earth terminal.
12. currency examine magnetic head as claimed in claim 11 is characterized in that, is filled with in the described metal shell for injection molding body fixing and that isolate.
13. currency examine magnetic head as claimed in claim 1 is characterized in that, this magnetic head further comprises the metal shell that holds described magnetoresistive transducer chip and described magnetic bias unit, and this shell has opening at magnetic head detection faces opposite side.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012205645396U CN203038357U (en) | 2012-10-31 | 2012-10-31 | Magnetically-biased currency-detection magnetic head with sensitive direction parallel to detection surface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012205645396U CN203038357U (en) | 2012-10-31 | 2012-10-31 | Magnetically-biased currency-detection magnetic head with sensitive direction parallel to detection surface |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203038357U true CN203038357U (en) | 2013-07-03 |
Family
ID=48690455
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2012205645396U Expired - Lifetime CN203038357U (en) | 2012-10-31 | 2012-10-31 | Magnetically-biased currency-detection magnetic head with sensitive direction parallel to detection surface |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203038357U (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103744038A (en) * | 2013-12-31 | 2014-04-23 | 江苏多维科技有限公司 | Short-distance magnetic resistance imaging sensor array |
| WO2014067462A1 (en) * | 2012-10-31 | 2014-05-08 | 江苏多维科技有限公司 | Magnetic head for banknote detection |
| CN103942872A (en) * | 2014-04-18 | 2014-07-23 | 江苏多维科技有限公司 | Small-fly-height inner-face magnetic image recognition sensor chip |
| WO2015010649A1 (en) * | 2013-07-26 | 2015-01-29 | 江苏多维科技有限公司 | Single reluctance tmr magnetic field sensor chip and currency detector magnetic head |
| WO2015144046A1 (en) * | 2014-03-25 | 2015-10-01 | 江苏多维科技有限公司 | Magneto resistance sensor for identifying magnetic image |
-
2012
- 2012-10-31 CN CN2012205645396U patent/CN203038357U/en not_active Expired - Lifetime
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014067462A1 (en) * | 2012-10-31 | 2014-05-08 | 江苏多维科技有限公司 | Magnetic head for banknote detection |
| US9721415B2 (en) | 2012-10-31 | 2017-08-01 | MultiDimension Technology Co., Ltd. | Magnetic head for banknote detection |
| WO2015010649A1 (en) * | 2013-07-26 | 2015-01-29 | 江苏多维科技有限公司 | Single reluctance tmr magnetic field sensor chip and currency detector magnetic head |
| US9804235B2 (en) | 2013-07-26 | 2017-10-31 | MultiDimension Technology Co., Ltd. | Single magnetoresistor TMR magnetic field sensor chip and magnetic currency detector head |
| CN103744038A (en) * | 2013-12-31 | 2014-04-23 | 江苏多维科技有限公司 | Short-distance magnetic resistance imaging sensor array |
| US10371761B2 (en) | 2013-12-31 | 2019-08-06 | MultiDimension Technology Co., Ltd. | Low profile magnetoresistive imaging sensor array |
| WO2015144046A1 (en) * | 2014-03-25 | 2015-10-01 | 江苏多维科技有限公司 | Magneto resistance sensor for identifying magnetic image |
| JP2017514114A (en) * | 2014-03-25 | 2017-06-01 | 江▲蘇▼多▲維▼科技有限公司Ｍｕｌｔｉｄｉｍｅｎｓｉｏｎ Ｔｅｃｈｎｏｌｏｇｙ Ｃｏ．， Ｌｔｄ． | Magnetoresistive magnetic imaging sensor |
| US10598743B2 (en) | 2014-03-25 | 2020-03-24 | Multidimension Technology Co., Ltd | Magnetoresistive magnetic imaging sensor |
| CN103942872A (en) * | 2014-04-18 | 2014-07-23 | 江苏多维科技有限公司 | Small-fly-height inner-face magnetic image recognition sensor chip |
| CN103942872B (en) * | 2014-04-18 | 2016-08-24 | 江苏多维科技有限公司 | Magnetic picture identification sensor chip in a kind of low fly height face |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102968845B (en) | A kind of sensitive direction by magnetic bias is parallel to the currency examine magnetic head of detection faces | |
| CN203038357U (en) | Magnetically-biased currency-detection magnetic head with sensitive direction parallel to detection surface | |
| CN202916902U (en) | Currency detection magnetic head with magnetic bias processing-based sensitive direction parallel to detection surface | |
| CN2788259Y (en) | Huge magnetic resistance sensor of paper money counter | |
| CN203224930U (en) | Chip type weak magnetism detection sensor | |
| US10288700B2 (en) | Magnetic sensor for detecting a vertical component of a magnetic field on the surface of a magnetic pattern | |
| CN102722932A (en) | Magnetic head of currency detector | |
| CN104157068A (en) | Magnetic sensor | |
| CN103814399A (en) | Measuring device for measuring magnetic properties of surroundings of measuring device | |
| CN103927811B (en) | A kind of magneto-resistor magnetic picture identification sensor | |
| JP6300506B2 (en) | Position sensor using variable magnetic collector | |
| CN211180162U (en) | Wide-range vertical sensitive magnetic sensor with feedback on closed-loop core | |
| CN102721938A (en) | Sensor for identifying magnetism of medium | |
| CN202694446U (en) | Currency detector magnetic head | |
| CN203433575U (en) | Sensor for identifying magnetic medium | |
| CN103971444A (en) | Magnetic sensor for magnetic detection | |
| CN104903938B (en) | For measuring the measuring device of magnetic characteristic around measuring device | |
| CN104167043A (en) | Chip-type weak magnetic detection sensor | |
| CN104157069A (en) | High-sensitivity sensor | |
| CN203275621U (en) | Magnetic sensor | |
| CN104215920B (en) | A kind of chip magnetic measurement sensor | |
| CN103268658B (en) | Magnetic moment orientation device for identifying magnetic graph on magnetic stripe and identification method of magnetic moment orientation device | |
| CN203217645U (en) | Magnetic moment orientation device for indentifying magnetic graphics on magnetic stripe | |
| CN110146737A (en) | A kind of wide range current sensor based on shunt magnetic structure | |
| CN104471355A (en) | Chip-type magnetic sensor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130703 |