CN204883909U - Coin test probe and detecting system thereof - Google Patents

Abstract

The utility model discloses a coin test probe, including a plurality of magnetic transducing units and electric current wire, the electric current wire is used for providing the excitation field pulse to the coin that awaits measuring to the messenger coin burble field of awaiting measuring, a plurality of magnetic transducing unit regular spread, the sensitive direction in magnetic field is the same for detect the vortex field, the magnetic transducing unit is single resistor structure or half -bridge structure or full -bridge structure, single resistor structure includes a magneto resistor, the half -bridge structure includes the magneto resistor of two series connection, the full -bridge structure includes four magneto resistors, the magneto resistor of two series connection wherein and the magnetism resistor parallel with of other two series connection, the magneto resistor is established ties and/or is connected in parallel by one or more magnetism sensing element and constitutes, magnetism sensing element is huge magnetism resistance element and/or magnetism tunnel junction component constitutes, the utility model also discloses a coin detecting system, the utility model discloses coin test probe precision is high, and is small, and dynamic is wide, the strong and low power dissipation of interference killing feature.

Description

A kind of Detecting of coin probe and detection system thereof

Technical field

The utility model relates to magnetic sensor techniques field, particularly a kind of Detecting of coin probe and detection system thereof.

Background technology

Along with coin uses more and more extensive, the dependency degree checking application for the value of money of coin, true and false judgement and coin in the mechanism such as traffic, finance is more and more higher.Existing checking for coin mainly contains three kinds with the mode of authenticity: (1) judges face amount and the true and false according to the weight of coin; (2) pattern of coin is optically detected to judge its face amount and the true and false; (3) judge that the material of coin detects the true and false of coin by then measuring its vortex field of inducting to coin applying high-frequency alternating magnetic field.For adopting the method for check weighing to detect coin, because counterfeit money is identical with the weight of coin, and in daily life, coin is due to wearing and tearing and contamination, and its weight is different, even if improve the measuring accuracy to weight, still cannot judge the true and false exactly, judge that the method for coin pattern is to detect coin for employing, because present counterfeit money is produced on pattern almost as broad as long with genuine note, existing accuracy of detection cannot distinguish genuine note and counterfeit money at all, the true and false is judged for the vortex field measuring coin, existing method is employing is that telefault is as current vortex sensor, the information detecting coin is obtained by the impedance analyzing coil, but its measuring accuracy and sensitivity lower, its length of penetration is also low, the vortex field signal of more depths cannot be measured, and poor anti jamming capability, and be an inductive coil due to what usually adopt in the market, only can measure the signal at a coin position, then its accuracy of measurement is also low-down, in the face of the pseudo-technology for making of more and more brilliant coin, we are not difficult to find out, existing Coin detecting equipment can not meet the high-precision requirement to Detecting of coin in the mechanism such as Modern Traffic and finance.

For the problems referred to above, China's publication number be CN103617669A to patent discloses a kind of giant magnetoresistance element or magnetic tunnel junction element of adopting be the coin detection sensor of sensitive element, it applies excitation field by drive coil to coin, now coin can produce certain vortex field, and magnetic field sensing cell coordinates the typical curve of coin to judge the true and false of coin by the distribution of measuring magnetic field.Adopt which measurement coin can realize the analysis of full frequency band in theory, there is the advantage of superhigh precision and small size, but but there is certain problem in actual production with in using in the coin detection sensor of the fabrication techniques adopting above-mentioned patent to disclose: (1) has inductance due to drive coil, loss can be produced, in order to can high-frequency signal be applied, the volume that drive coil often designs is very large, and therefore its power consumption is very high, easily generates heat; (2) circuit separating high-frequency signal is often very complicated, and the volume shared by this circuit is very large and solution value precision is on the low side; (3) noise signal near eddy current coil frequency is very serious, is difficult to filtering.

As can be seen from above-mentioned, existing Detecting of coin mode can not meet high precision and the little requirement of volume simultaneously.

Summary of the invention

Technical problem to be solved in the utility model overcomes the deficiencies in the prior art and provides a kind of Detecting of coin to pop one's head in and detection system, and Detecting of coin probe precision of the present utility model is high, and volume is little, wide dynamic range, and antijamming capability is strong and low in energy consumption.

The utility model is for solving the problems of the technologies described above by the following technical solutions:

According to a kind of Detecting of coin probe that the utility model proposes, comprise multiple magnetic transducing unit and current lead,

Described current lead is used for providing excitation field pulse to coin to be measured, thus makes coin to be measured produce vortex field;

Described multiple magnetic transducing unit rules arrangement, magnetic-field-sensitive direction is identical, in order to detect vortex field.

To pop one's head in further prioritization scheme as a kind of Detecting of coin described in the utility model, described magnetic transducing unit imports alternating current.

To pop one's head in further prioritization scheme as a kind of Detecting of coin described in the utility model, described magnetic transducing unit is single electric resistance structure or half-bridge structure or full bridge structure; Described single electric resistance structure comprises a magneto-resistor; Described half-bridge structure comprises the magneto-resistor of two series connection; Described full bridge structure comprises four magneto-resistors, and the magneto-resistor that the magneto-resistor of two series connection is wherein connected with another two is in parallel; Described magneto-resistor is connected by one or more magnetic sensor elements and/or parallel connection is formed.

To pop one's head in further prioritization scheme as a kind of Detecting of coin described in the utility model, described magnetic sensor elements is anisotropic magnetoresistance element, giant magnetoresistance element and/or magnetic tunnel junction element; Described half-bridge structure is for recommending half-bridge or with reference to half-bridge or gradient half-bridge, and described full bridge structure is for recommending full-bridge or with reference to full-bridge or gradient full-bridge.

To pop one's head in further prioritization scheme as a kind of Detecting of coin described in the utility model, also comprise operational amplifier, described operational amplifier is connected with magnetic transducing unit.

To pop one's head in further prioritization scheme as a kind of Detecting of coin described in the utility model, described current lead provides the excitation field pulse of different frequency to coin to be measured.

To pop one's head in further prioritization scheme as a kind of Detecting of coin described in the utility model, described current lead provides excitation field pulse to be square wave to coin to be measured.

To pop one's head in further prioritization scheme as a kind of Detecting of coin described in the utility model, described multiple magnetic transducing unit forms a line or multiple row, and the magnetic-field-sensitive direction of each magnetic transducing unit is identical.

To pop one's head in further prioritization scheme as a kind of Detecting of coin described in the utility model, also comprise wave filter, described wave filter is connected with magnetic transducing unit.

A kind of Detecting of coin system, comprises Detecting of coin as above probe, detection module; Wherein,

Current lead in described Detecting of coin probe is used for providing excitation field pulse to coin to be measured, thus makes coin to be measured generation frequency be ω ₁vortex field;

It is ω that magnetic transducing unit in described Detecting of coin probe imports frequency ₀alternating current, magnetic transducing unit is ω for detecting vortex field and exporting crest frequency ₁, ω ₁-ω ₀and ω ₁+ ω ₀signal to detection module;

Detection module is used for ω ₁and/or ω ₁-ω ₀and/or ω ₁+ ω ₀as judging that the characteristic signal frequency of Coin truth carries out check processing.

The utility model adopts above technical scheme compared with prior art, has following technique effect: Detecting of coin probe precision of the present utility model is high, and volume is little, wide dynamic range, and antijamming capability is strong and low in energy consumption.

Accompanying drawing explanation

Fig. 1 is the structural representation of the Detecting of coin probe that the utility model proposes.

Fig. 2 is the electrical connection schematic diagram of gradient full-bridge type magnetic transducing unit.

Fig. 3 is the physical location schematic diagram of gradient full-bridge type magnetic transducing unit.

Fig. 4 is the spectrum analysis curve of single channel magnetic transducing unit.

Reference numeral in figure is interpreted as: 1-magnetic-field-sensitive direction, 11a-first magnetic transducing unit, 11b-second magnetic transducing unit, 11c-the 3rd magnetic transducing unit, 11n-n-th magnetic transducing unit, 12-current lead, 13-PCB, 20-coin to be measured, 21-first magneto-resistor, 22-second magneto-resistor, 23-the 3rd magneto-resistor, 24-the 4th magneto-resistor, 25-the 5th magneto-resistor, 26-the 6th magneto-resistor, 27-the 7th magneto-resistor, 28-the 8th magneto-resistor, 11-magnetic transducing unit, 32-vortex field.

Embodiment

Below in conjunction with accompanying drawing, the technical solution of the utility model is described in further detail:

Technical scheme in the application is understood better in order to make those skilled in the art person, below in conjunction with the accompanying drawing in the embodiment of the present application, technical scheme in the embodiment of the present application is clearly and completely described, obviously, described embodiment is only some embodiments of the present application, instead of whole embodiments.Based on the embodiment in the application, those of ordinary skill in the art are not making the every other embodiment obtained under creative work prerequisite, all should belong to the scope of the application's protection.

As shown in Figure 1, the Detecting of coin probe that the utility model proposes comprises multiple magnetic transducing unit (11a, 11b, 11c ... 11n), current lead 12, n be greater than 1 integer, pin (not indicating in figure) is drawn in PCB13 and output.The magnetic-field-sensitive direction 1 of described multiple magnetic transducing unit is identical, forms a line, and with these row for y-axis, the side of coin 20 to be measured is parallel to y-axis.The magnetic-field-sensitive direction 1 of multiple magnetic transducing unit is parallel to z-axis, and the direct of travel of coin to be measured 20 is x-axis, and wherein, x, y, z axle is parallel between two.Multiple magnetic transducing unit and current lead 12 are arranged on PCB13, and multiple magnetic transducing unit is positioned at the side of current lead 12 along the z-axis direction.During work, current lead 12 applies excitation field to coin 20 to be measured, coin 20 to be measured therefore produce current vortex, form vortex field 32 near current vortex simultaneously, multiple magnetic transducing unit is then in order to measure the vortex field 32 of position, and draw pin by output export rear end to by organizing signal more, therefore can scan the signal of the vortex field 32 on the whole surface of its side after coin to be measured passes through, wherein the direction of motion of coin to be measured is x-axis.Wherein, output is drawn pin and is electrically connected with multiple magnetic transducing unit and current lead 12 respectively, is used for importing working current and output signal.Multiple magnetic field sensing cell and current lead 12 can be arranged on PCB13, and also accessible site is on a chip (Die), also by a single die integrated for multiple magnetic transducing unit, can be integrated on another chip by current lead 12.Adopt current lead 12 to replace the volume that drive coil can reduce probe greatly, probe can be set to frivolous PCB structure or directly be integrated into chip, achieve the small size of such sensor and lightening.Current lead 12 and multiple magnetic transducing unit all have corresponding input end and output terminal, and described output terminal is connected with rear end with the mode of input end by welding or lead-in wire.

The length of penetration of excitation field and its frequency dependence and be inversely proportional to, therefore the length of penetration of low-frequency range is high, but its vortex field density is little, and the sensitivity of the telefault sensing unit usually adopted and precision all very low, the vortex field of low-frequency range cannot be recorded, its output signal narrow dynamic range and the eddy current signal of more depths under material surface cannot be measured, what the magnetic transducing unit of therefore popping one's head at the Detecting of coin that the utility model proposes adopted is the anisotropic magnetoresistance element that sensitivity and precision are all very high, giant magnetoresistance element or magnetic tunnel junction element are sensitive element, according to existing technology, above-mentioned anisotropic magnetoresistance element, the resistance value R of giant magnetoresistance element or magnetic tunnel junction element with outfield H at its saturation field-H _sand H _sbetween linear change, when the outfield applied is greater than the absolute value of its saturation field along the absolute value of the field intensity of its sensitive direction, its resistance is constant, and namely this magnetic sensor elements is saturated.Owing to adopting multiple magnetic transducing unit mode arranged in columns to scan coin, can obtain the vortex field signal in a coin face, i.e. the magnetic image of whole tested surface, the magnetic signal measuring single position than single magnetic transducing unit has higher precision.

Giant magnetoresistance element or tunnel magneto resistance element are the multi-layer film structure of nanometer grade thickness; Described multi-layer film structure comprises nano-level thin-membrane free layer, nonmagnetic layer and pinning layer, and nano-level thin-membrane free layer, pinning layer lay respectively at the both sides up and down of nonmagnetic layer.By magnetosphere, (magnetosphere is as CoFe, FeNi etc. by the alloy of Fe, Co, Ni or above-mentioned three kinds of ferromagnetic materials to free layer, or the single thin film that forms as CoFeB etc. of the alloy of Fe, Co, Ni and other nonmagnetic substances or multiple layer film) form, also can be that (its intermediate interlayer is that nonmagnetic material is formed to SAF layer (i.e. the multi-layer compound structure of magnetosphere-wall-magnetosphere three-decker or magnetosphere-wall) structure, be generally Ru, Ta, Pt, Pb etc.), its magnetic moment changes with outfield; Nonmagnetic layer is made up of nonmagnetic substance, if giant magnetoresistance element, then nonmagnetic layer is metal material, as Cu, Al etc., if magnetic tunnel junction element, is then nonmetallic materials, as AlO, MgO, HfO, ZrO or TaO etc.; The magnetic moment of pinning layer is constant, normally magnetosphere-inverse ferric magnetosphere composite structure or SAF layer-inverse ferric magnetosphere structure.When free layer magnetic moment and pinning layer magnetic moments parallel, the resistance R of element is minimum; When free layer magnetic moment and pinning layer magnetic moment antiparallel, the resistance R of element is maximum.The specific works mode of giant magnetoresistance element or magnetic tunnel junction element can be the patent of CN103926543A with reference to Chinese publication number: based on the magnetic head of magneto-resistor technology.

Magnetic transducing unit 11 can be single resistance, half-bridge or full bridge structure usually.The brachium pontis of described single resistance, half-bridge or full-bridge is connected by one or more identical magnetic sensor elements (giant magnetoresistance element or magnetic tunnel junction element) and/or is composed in parallel, each brachium pontis we can be equivalent to a magneto-resistor, the magnetic-field-sensitive direction of the magnetic sensor elements in each brachium pontis is identical.Aforesaid single electric resistance structure contains a magneto-resistor, and half-bridge structure is composed in series by the magneto-resistor that two physical propertys are identical, and full bridge structure is connected and composed by the magneto-resistor that four physical propertys are identical.The working mechanism of above-mentioned single resistance, half-bridge and full bridge structure can with reference to the patent of Chinese publication number CN103617669A: a kind of Coin detection device.

In the utility model, the structure of prioritizing selection is gradient full bridge structure, below will elaborate this structure.Fig. 2, Fig. 3 are electrical connection and the physical location schematic diagram of the gradient full-bridge magneto-resistor that the present embodiment adopts, and be the putting position of first to fourth magneto-resistor 21,22,23,24 for the first magnetic transducing unit 11a, Fig. 3, Fig. 2 is its electric connection mode.We can see that magnetic-field-sensitive direction 1, first magneto-resistor 21 along magnetic transducing unit 11 is identical with the position of the 4th magneto-resistor 24, and the second magneto-resistor 22 is identical with the position of the 3rd magneto-resistor 23, between two input solder joints, pass into constant voltage or electric current.Under the effect not having outfield, the resistance of first to fourth magneto-resistor 21,22,23,24 is identical, no-output.When vortex field 32 puts in four magneto-resistors, because this magnetic field is gradient fields, field intensity along gradient fields direction varies in size, the first then identical along gradient direction position magneto-resistor 21 is identical with the resistance change of the 4th magneto-resistor 24, second magneto-resistor 22 is identical with the resistance change of the 3rd magneto-resistor 23, first magneto-resistor 21 is different with the change in resistance of the second magneto-resistor 22 (23 and 24), then the output terminal V of gradient full-bridge ₁+ and V ₁-between there is output voltage V _out.

Above-mentioned is the working method of gradient full-bridge adopting direct drive, and in actual measurement, owing to having much noise near the frequency of vortex field, affect measuring accuracy, for this reason, it is ω that drive source is set to frequency by us ₀alternating current, introduce modulation signal in order to change output signal frequency, then have:

Measuring-signal: f ₁=A ₁cos (ω ₁t)

Modulation signal: f ₂=A ₂cos (ω ₀t)

Then output signal is: $\begin{array}{c}{V}_{out}=f_1\·f_2=A_1{A}_2\·\cos \left({\mathrm{\ω}}_{1}t\right)\cos \left({\mathrm{\ω}}_{0}t\right)\\ =\frac{A_1{A}_2}{2}\·\[\cos \left({\mathrm{\ω}}_1+{\mathrm{\ω}}_0\right)t+\cos \left({\mathrm{\ω}}_1-{\mathrm{\ω}}_0\right)t\]\end{array}$

Wherein, A ₁, A ₂constant, ω ₁the frequency of vortex field, ω ₀for drive source frequency, t is the time.As can be seen from the above equation, output signal can be decomposed into and vortex field frequencies omega ₁(the ω that difference is larger ₁+ ω ₀) and (ω ₁-ω ₀) these two parts, we become process of heterodyning to adopt this solution, and as shown in Figure 4, its characteristic peaks is direct current component, (ω to its spectrogram ₁-ω ₀) frequency-portions, ω ₁frequency-portions, the saturated peak that causes and (ω ₁+ ω ₀) frequency-portions, from figure, we can be clear that in vortex field frequencies omega ₁near have a large amount of noises.Adopting process of heterodyning to solve us can with (ω ₁-ω ₀) frequency-portions is characteristic spectral line, filtering and useful signal frequencies omega ₁close noise, owing to useful signal be divide into two parts larger with primary frequency difference---(ω ₁-ω ₀) frequency-portions and (ω ₁+ ω ₀) frequency-portions, we can adopt these two parts as characteristic spectral line simultaneously, also can adopt above-mentioned any one frequency range between the two arbitrarily, or adopt ω ₁frequency-portions, or (ω ₁-ω ₀) frequency-portions, (ω ₁+ ω ₀) frequency-portions and this three of frequency-portions appoint get two be one group as characteristic spectra, in reality to solving of exporting, in order to reduce power consumption, reduce the peripheral circuit of redundancy, can only to the difference (ω of survey frequency and driving frequency ₁-ω ₀) frequency-portions judges as characteristic spectral line, by the wave filter filtering of other frequency-portions.If need more high-precision judgement, also (ω can be adopted ₁-ω ₀) frequency-portions, ω ₁frequency-portions and (ω ₁+ ω ₀) these three parts of frequency-portions are as characteristic spectral line.

The excitation field pulse of current lead 12 can be square wave, because square wave can Fourier expansion, can think full frequency band.Above-mentioned vortex field frequencies omega ₁might not be a frequency range, such as, when excitation field pulse is square wave, then vortex field frequencies omega ₁it is exactly full frequency band.

The electric connection mode of multiple magnetic transducing unit as shown in Figure 2, multiple magnetic transducing unit (11a, 11b ... 11n) in parallel, unification provides drive current by rear end, and many group output signals are passed to rear end and carry out processing and analyzing.Many groups output signal can directly export, also by exporting after wave filter and/or operational amplifier process.

Should be appreciated that above is illustrative and not restrictive by preferred embodiment to the detailed description that the technical solution of the utility model is carried out.Those of ordinary skill in the art can modify to the technical scheme described in each embodiment on the basis of reading the utility model instructions, or carries out equivalent replacement to wherein portion of techniques feature; And these amendments or replacement, do not make the essence of appropriate technical solution depart from the spirit and scope of each embodiment technical scheme of the utility model.

Claims (10)

1. a Detecting of coin probe, comprises multiple magnetic transducing unit and current lead, it is characterized in that,

Described current lead is used for providing excitation field pulse to coin to be measured, thus makes coin to be measured produce vortex field;

Described multiple magnetic transducing unit rules arrangement, magnetic-field-sensitive direction is identical, in order to detect vortex field.

2. a kind of Detecting of coin probe as claimed in claim 1, it is characterized in that, described magnetic transducing unit imports alternating current.

3. a kind of Detecting of coin probe as claimed in claim 1, is characterized in that: described magnetic transducing unit is single electric resistance structure or half-bridge structure or full bridge structure; Described single electric resistance structure comprises a magneto-resistor; Described half-bridge structure comprises the magneto-resistor of two series connection; Described full bridge structure comprises four magneto-resistors, and the magneto-resistor that the magneto-resistor of two series connection is wherein connected with another two is in parallel; Described magneto-resistor is connected by one or more magnetic sensor elements and/or parallel connection is formed.

4. a kind of Detecting of coin probe as claimed in claim 3, is characterized in that: described magnetic sensor elements is anisotropic magnetoresistance element, giant magnetoresistance element and/or magnetic tunnel junction element; Described half-bridge structure is for recommending half-bridge or with reference to half-bridge or gradient half-bridge, and described full bridge structure is for recommending full-bridge or with reference to full-bridge or gradient full-bridge.

5. a kind of Detecting of coin probe as claimed in claim 1, it is characterized in that: also comprise operational amplifier, described operational amplifier is connected with magnetic transducing unit.

6. a kind of Detecting of coin probe as claimed in claim 1, is characterized in that: described current lead provides the excitation field pulse of different frequency to coin to be measured.

7. a kind of Detecting of coin probe as claimed in claim 1, is characterized in that: described current lead provides excitation field pulse to be square wave to coin to be measured.

8. a kind of Detecting of coin probe as claimed in claim 1, is characterized in that: described multiple magnetic transducing unit forms a line or multiple row, and the magnetic-field-sensitive direction of each magnetic transducing unit is identical.

9., as a kind of Detecting of coin probe in claim 1-8 as described in any one, it is characterized in that: also comprise wave filter, described wave filter is connected with magnetic transducing unit.

10. a Detecting of coin system, is characterized in that, comprises Detecting of coin as claimed in claim 1 probe, detection module; Wherein,

Current lead in described Detecting of coin probe is used for providing excitation field pulse to coin to be measured, thus makes coin to be measured produce frequency to be ω ₁vortex field;

Magnetic transducing unit in described Detecting of coin probe imports frequency and is ω ₀alternating current, magnetic transducing unit for detecting vortex field and exporting crest frequency is ω ₁, ω ₁- ω ₀with ω ₁+ ω ₀signal to detection module;

Detection module is used for will ω ₁and/or ω ₁- ω ₀and/or ω ₁+ ω ₀as judging that the characteristic signal frequency of Coin truth carries out check processing.