JPH07296130A - Magnetic marker - Google Patents

Abstract

PURPOSE:To provide the marker for electronic article monitoring system which improves strength and sharpness for outputting signals at a higher-order resonance frequency. CONSTITUTION:Concerning the marker, this is composed of a laminated object laminating a hard magnetic metal plate (A) 1 and a magneto-strictive metal plate (B)2, which is mechanically resonated at a prescribed frequency in the incidental AC magnetic field of a frequency to be fluctuated in the state of magnetizing the metal plate (A) 1 so as to change magnetic flux density and magnetic permeability but is not resonated at the prescribed frequency in the state of not magnetizing that plate (A)1 so as not to change magnetic flux density and magnetic permeability, so as to resonate the metal plate (B)2, the metal plate (A)1 is divided into plural magnetic domains and magnetized so that the N poles of two adjacent domains can face each other. The magnetostrictive metal plate (B)2 is a magnetostrictive metal plate provided with the hysteresis loss from 0.05 to 5J/m<3> at a frequency 1KHz and in the AC magnetic field whose maximum magnetic field is 0.25ersteds.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic marker such as a data carrier, and more particularly to a magnetic marker for reading identification information such as collation data.

[0002]

2. Description of the Related Art Magnetic markers typified by magnetic recording media are widely used for bank cash cards, bankbooks, railway commuter passes, and tickets due to the convenience of magnetic recording. Abrasion and damage occur. As a non-contact, simple information medium, a bar code system is generally used.
There are difficulties such as not being able to write.

Therefore, recently, as a completely new magnetic application identification system, WO92 / 12401, WO92 / 12402, etc. by Demes Andrew Nicholas et al. Developed a plurality of bias magnetic fields by devising the magnetization state of a hard magnetic material. Magnetic markers have been proposed in which ductile stripes of a single ferromagnetic magnetostrictive material tuned to participate mechanically resonate at different preselected frequencies.

The above-mentioned WO92 / 12401 and WO92
/ 12402 proposes to use an amorphous metal such as Methgrass "2605" manufactured by Allied Chemical Co., Ltd. or silicon steel as the ferromagnetic magnetostrictive material.

[0005]

However, in the marker described in the above publication, the problem of obtaining a high-order resonance frequency with high strength remains unsolved. Therefore, it has been completely unclear as to the preferable characteristics of the ferromagnetic magnetostrictive material for that purpose.

[0006]

Therefore, the inventors of the present invention, in order to master the markers described in the above publications,
As a result of diligent studies on a magnetostrictive metal plate capable of obtaining a high-order resonance frequency with high strength, in an alternating magnetic field with a frequency of 1 KHz and a maximum magnetic field of 0.25 Oersted,
It was found that the use of a magnetostrictive metal plate having a hysteresis loss of 0.05 to 5 J / m ³ is extremely important for increasing the strength of output and sharpness of output at higher resonance frequencies, The present invention has been completed.

Next, the resonance frequency generating type marker of the present invention will be described. This marker mechanically resonates with a hard magnetic metal plate (A) at a predetermined frequency in an incident AC magnetic field with a varying frequency in a state where the metal plate (A) is magnetized, and the magnetic flux density and transmission A metal plate (B) having magnetostriction, which does not resonate at the predetermined frequency in the state where the magnetic susceptibility is changed and is not magnetized, and the magnetic flux density and the magnetic permeability are not changed, It is composed of a laminated material that is laminated so that it can resonate physically.

The characteristic feature of this type of marker is that the frequency of forming the magnetic field is gradually changed from a low frequency to a high frequency or from a high frequency to a low frequency. In the state where the coating film is magnetized, a predetermined frequency at which the magnetic flux density or magnetic permeability changes is generated as a signal and responds to an alternating magnetic field. In this type of marker, when the metal plate (A) is not magnetized, the metal plate (B) is based on a predetermined frequency at which the magnetic flux density or permeability changes with respect to the fluctuating incident AC magnetic field. No output signal is generated.

In the resonance frequency generating marker, the metal plate (A) and the metal plate (B) must be laminated so that the metal plate (B) can mechanically resonate. In the case of this type of marker, it should be noted that if the metal plate (A) and the metal plate (B) are adhered, they will not function as markers. Typically, a structure in which a metal plate (B) is embedded in a hollow portion of a hexahedron provided with a metal plate (A) on at least one surface so that the metal plate (B) can resonate in the same direction as the coating film. Is mentioned.

An example of the structure of the marker used in the present invention will be described below. The basic structure of the marker for an electronic article monitoring system is, for example, as shown in FIG. 1, a metal plate 2 having magnetostriction and a non-magnetic housing 3 having a storage space so that the metal plate 2 mechanically resonates. , And a hard magnetic metal plate 1 serving as a lid of the non-magnetic casing 3.

The non-magnetic casing 3 may have its bottom portion and the outer edge portion (frame portion) of a desired height separately obtained, and these components may be bonded together, or they may be obtained as one component from the beginning. You may use the thing.

The hard magnetic metal plate 1 and the non-magnetic housing 3 in which the metal plate 2 having magnetostriction is contained without being fixed are not connected or fixed, but for example, contact portions thereof are not shown. Examples thereof include a method of forming a composite shape that can integrate the shapes, a method of using a pressure-sensitive adhesive, and a method of using an adhesive tape.

The hard magnetic metal plate (A) is a metal plate having a coercive force higher than that of the metal plate (B) described later, for example, a metal having a coercive force of 20 Oersted or more, and the magnetic force can be retained therein. This is a plate, and it gives a bias magnetic field to the metal plate (B) described later. Such a metal plate (A) is disclosed in, for example, JP-A-58-192.
SAE1095 as described in Japanese Patent Publication No. 197
A flat strip of a metal material having a high coercive force such as steel, baicalloy, remalloy, and anochrome can be used. Further, for example, a thin body of a ferromagnetic metal such as stainless steel, nickel, ferrite or soft iron as described in WO92 / 12402 can be used. The thickness of the metal plate (A) is
For example, it is 20 μm to 1 mm.

As the non-magnetic housing 3, for example, a molded rectangular tray-shaped plastic case can be used. Of course, this case may be formed by molding a thermoplastic resin or may be formed by curing and molding a thermosetting resin.

Examples of the thermoplastic resin include polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polymethylmethacrylate, polystyrene, polyvinyl chloride, polyurethane resin, polycarbonate resin, ABS resin, polyamide resin and "Delrin" (DuPont, USA). Company trademark, polyacetal resin) and the like.

As the thermosetting resin, for example, acid anhydride,
Examples thereof include a combination of at least one curing agent selected from the group consisting of polyamine compounds and polyamide resins and an epoxy resin, a combination of polyamine and a novolac type phenol resin, a resol type phenol resin, an unsaturated polyester resin and the like.

In the present invention, the metal plate (B) having magnetostriction
However, it is characterized by using a magnetostrictive metal plate having a hysteresis loss of 0.05 to 5 J / m ³ in an alternating magnetic field having a frequency of 1 KHz and a maximum magnetic field of 0.25 oersted.

Next, in order to understand the importance of using the above-mentioned metal plate having a specific magnetostrictive property in the present invention, the magnetic energy given as an alternating magnetic field to the magnetic marker of the present invention is A process of converting the metal plate (B) in the magnetic marker into mechanically resonating energy will be described.

The resonance frequency of the metal plate (B) having magnetostriction is expressed by the following equation 1.

[0020]

## EQU1 ## fn = (n / 2L). (E / D) ^1/2 ... Equation 1

In the above formula 1, L, E and D are respectively
It represents the length of the ribbon, the Young's modulus, and the mass density, and n represents the order of the resonant harmonic.

At the resonance frequency represented by the above equation 1, the magnetic energy applied to the metal plate (B) is converted into mechanical resonance energy. At this time, energy loss due to hysteresis loss and eddy current loss is considered due to the hysteresis and resistivity of the metal plate (B).

In the present invention, when the metal plate (B) resonates with the magnetic energy given from the alternating magnetic field at the frequency expressed by the equation 1, the magnetic flux density or the magnetic permeability increases at the same time, which causes the signal output. Obtained as. It is desirable that the given magnetic energy be converted into mechanical resonance energy with a conversion efficiency as high as possible.

However, since it is difficult to expect 100% conversion efficiency, in the present invention, among the AC loss,
The most important consideration is hysterisis loss.

The hysteresis loss per second is W _h A
lf (where W _h is the area enclosed by the hysteresis curve, A is the cross-sectional area, l is the length, and f is the frequency).
Therefore, if the sample volume is constant, the hysteresis loss is proportional to the area surrounded by the hysteresis curve and the frequency f. The coercive force of the metal plate (B) is usually 0.5 oersted or less, but the residual magnetic flux density may be high. In that case, the hysteresis loss, which is an AC loss, cannot be ignored.

The hysteresis loss per second is the frequency f
Proportional to. Therefore, the difference in the hysteresis loss measured at a frequency of 1 KHz is the same as the difference in the type of the metal plate (B) in the measurement at a higher frequency.

Therefore, the magnetostrictive metal plate (B) is
It is desirable that the hysteresis loss at the resonance frequency is as small as possible. The frequency is 1 KHz and the maximum magnetic field is 0.25.
0.05-5 J / m ³ in an Oersted AC magnetic field
Is particularly desirable.

On the other hand, the eddy current loss per ^second is f ²
B ² / ρ (where f is frequency, B is magnetic flux density, and ρ is resistivity). Therefore, the eddy current loss is the frequency f
And is inversely proportional to the resistivity ρ. The resonance frequency of the magnetostrictive metal plate (B) expressed by the equation 1 is inevitable even when the harmonic order n is high or the stripe length is short, and the resonance frequency inevitably exceeds 1 MHz. Occurs.

Therefore, it is desirable that the metal plate (B) has a resistivity as high as possible, and the resistivity is 135 to 200 μm.
The range of Ω-cm is particularly desirable. This is because when the electric resistance of the metal plate (B) is as small as 120 to 160 μΩ-cm, the eddy current loss cannot be ignored at high frequencies.

The metal plate (B) can be selected from ferromagnetic and magnetostrictive metal plates and has a frequency of 1 KH.
z, 0.05-5 J / m ³ in an alternating magnetic field with a maximum magnetic field of 0.25 Oersted, and a resistivity of 135-20
The use of the magnetostrictive metal plate having 0 μΩ-cm can further reduce the above-mentioned energy loss, and as a result, can enhance the output intensity and the sharpness at higher resonance frequencies. Therefore, it is particularly preferable.

The metal plate (B) is, for example, a magnetostrictive metal plate having a ferromagnetism, a low coercive force, and a high magnetic permeability, which has a coercive force of less than 1 oersted and a magnetic permeability of 10 ³ order or more. It is preferable to select and use one having the above-mentioned specific hysteresis loss. Specifically, some amorphous metal materials have the above-mentioned specific range of hysteresis loss, and examples thereof include Methograss "2826MB" manufactured by Allied Chemicals.

The shape of the metal plate is usually a rectangle having long sides and short sides, the length of the long side is 3 to 100 mm, and the thickness thereof is usually 20 to 30 μm.

Next, a method of magnetizing the marker of the present invention will be described. In the present invention, from the metal plate (A),
The metal plate (A) is magnetized in order to apply a bias magnetic field toward the metal plate (B). The magnetizing method is such that one surface in the longitudinal direction of the metal plate (A) is divided and magnetized so as to have a plurality of magnetized sections, which is N of one of the two adjacent sections. The pole and the north pole of the other section adjacent to the pole must be divided and magnetized so as to at least face each other.

Since there are only two types of magnetic poles, the S pole and the N pole, "the N pole of one of the two adjacent sections and the N pole of the other section adjacent to it are the same. The expression "at least face each other" is exactly the same as the expression "the S pole of one of the two adjacent sections and the S pole of the other section adjacent to it at least face each other". Is the meaning of.

The natural frequency at which the metal plate (B) mechanically resonates is represented by the above-mentioned formula 1, and generates a bias magnetic field applied to the metal plate (B) that resonates with the incident AC magnetic field. The magnetized state of the metal plate (A) is shown in FIG. 2, for example.

The state that "the N pole of one of the two adjacent sections and the N pole of the other section adjacent thereto are at least dividedly magnetized so as to face each other" is as follows:
When n magnetized sections having N poles and S poles are arranged side by side, two arbitrarily magnetized adjacent two magnetized sections, for example, (n
-2) It is shown that the north poles of the (n-1) th section and the (n-1) th section are magnetized so as to face each other (that is, the N poles face each other and face each other). ing.

In the example of FIG. 2, the N pole and n = in the section of n = 2.
The N poles in the section 3 are facing each other, and the S poles in the section n = 1 and the S poles in the section n = 2 are facing each other.

In the marker of the present invention, the number of longitudinally magnetized sections on the metal plate (A) is plural, that is, two or more. The number of sections depends on the length of the metal plate (A) in the longitudinal direction, but when using a section of about 10 cm, for example,
The number of sections is usually 2 to 50.

As for the magnetization, the whole one surface in the longitudinal direction of the metal plate (A) may be divided and magnetized, or a part of the surface may be divided and magnetized. The widths of the magnetized sections may all be the same width (that is, a state in which the magnetized sections are magnetized equally at equal intervals), or may have different widths. Usually, the entire one surface in the longitudinal direction of the metal plate (A) is magnetized, and all the magnetized sections have the same width (that is, a state in which the metal plate (A) is magnetized in equal intervals at equal intervals).

As shown in FIG. 2, magnetic information is recorded on the metal plate 1, that is, a metal plate (A) having a length L is magnetized to generate a bias magnetic field toward the metal plate (B). As a method of making it possible, as shown in FIG. 3, for example, a writing method of magnetic recording by an ordinary encoder or the like can be followed.

There are two writing methods, for example, a sine wave recording method and a digital magnetic recording method. As a recording method, for example, recording by a ring head or a method by a magnetizer can be used.

FIG. 4 shows the identification information corresponding to the magnetic recording of the non-contact magnetic marker of the present invention having the metal plate 2 [metal plate (B)] and the metal plate 1 [metal plate (A)]. A schematic diagram of an example of a contact detection system is shown.

The apparatus 100 includes a transmitter 101 for generating a sine wave capable of sweeping a frequency, an output amplifier 102 for amplifying the sine wave signal, and an amplified sine wave signal according to the shape thereof. Metal plate 2 having properties
And an exciting coil 103 capable of applying an alternating magnetic field. The exciting coil 103 is made to generate an incident AC magnetic field having a varying frequency.

The apparatus 200 comprises a pickup coil coaxially arranged inside the exciting coil 103 and a spectrum analyzer 202 capable of measuring the amplitude of the response by detecting the frequency at which the metal plate 2 in the marker mechanically resonates. Become. Since the magnetic marker of the present invention is magnetized so as to have a plurality of sections in advance, the metal plate 2 in the marker resonates at the specific frequency of the above-described Expression 1 in the above-mentioned incident AC magnetic field, respond.

Therefore, when the frequency of the alternating magnetic field is swept near fn, a characteristic signal is generated. This is because when an alternating magnetic field and a bias magnetic field are introduced into the metal plate 2 in the marker, its energy is alternately accumulated and released in magnetic energy and mechanical energy depending on the frequency of the alternating magnetic field. The stored and released magnetostrictive energy is maximal at the material's mechanical resonance frequency.

Due to the accumulation and release of this energy, a voltage is induced in the pickup coil 201 via the magnetic permeability of the metal plate 2, that is, the change in magnetic flux density. Therefore, it is possible to determine the identification information of the non-contact magnetic marker by examining the characteristic frequency component of the output signal induced in the pickup coil 201.

Oscillator 1 for generating an incident AC magnetic field
The frequency of 01 is preferably in the range of 10 KHz to 5 MHz. The strength of the magnetic field generated in the exciting coil 103 is, for example, 5 Oersted, and the magnetic field of this level does not erase or attenuate the recorded information on the metal plate 1 of the present invention.

Since the marker of the present invention uses a metal plate having a magnetostrictive property with a specific hysteresis loss, the output at the resonance frequency does not decrease significantly even if the resonance frequency becomes high, and the resonance frequency is high. The sharpness of the output at (which can be represented by a Q value, for example) is also high. Therefore, it has become possible to increase the recording density. In particular, this tendency becomes particularly remarkable when it is necessary to detect higher-order resonance frequencies of the fifth order or higher.

Of course, also in the case of detecting resonance frequencies of the 2nd to 4th order, the marker of the present invention has higher output intensity and higher than the marker obtained by using the conventional metal plate having magnetostriction. A sharpness response signal is obtained. These were surprising results that were completely unexpected from the prior art.

[0050]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples.

(Example) Thickness of 25 μm, resistivity of 160 μ
Ω-cm Fe-Ni-Mo-B type metoglas "282
6 MB "(manufactured by Allied Chemical Co., Ltd., thickness: 28 μm) was cut into a width of 2 mm and a length of 100 mm to prepare a magnetostrictive metal plate (B1). This metal plate, frequency 1K
AC magnetic characteristics were measured with an AC magnetization measuring device (manufactured by Riken Denshi Co., Ltd.) under an excitation condition of Hz and maximum magnetic field strength of 0.25 Oersted.

A window having a width of 3 mm and a length of 102 mm was opened in the central portion of a milky white polyethylene terephthalate plate having a thickness of 250 μm and a size of 150 mm × 50 mm, and a thickness of 250 μm.
A 150 mm × 50 mm milk-white polyethylene terephthalate plate was adhered to form a rectangular tray case used for a non-contact magnetic marker. Then, the metal plate (B
1) was inserted so that mechanical resonance could occur.

As a hard magnetic metal plate (A1), 150m
A Co-Fe-Ni ferromagnetic metal ribbon (Vacuumshmelze, Germany, thickness: 66 μm) cut into a size of m × 50 mm was used to form a rectangular tray case with a metal plate (B1) in the window. 5mm
The non-contact magnetic marker of the present invention was obtained by punching into a size of 105 mm.

The metal plate (A1) at a position corresponding to the end face portion of the metal plate (B1) in the marker so that the 6th harmonic of the frequency 130 KHz and the 29th harmonic of the frequency 620 KHz resonate from the marker and are generated. The top is 100/6 mm, 1
The encoder was magnetized so that the magnetization was saturated at regular intervals of 00/29 mm.

Next, a system for contactlessly detecting the identification information corresponding to the contactless magnetic marker shown in FIG. 4 was prepared.

An exciting coil 103 was prepared by winding a copper wire having a diameter of 1 mm 200 times around a core having an inner diameter of 60 mm. Further, a copper wire having a diameter of 0.1 mm was wound 50 times around a core having an inner diameter of 10 mm to prepare an operation type pickup coil 201, which was inserted into the exciting coil 103. These exciting coil 103 and pickup coil 201 are combined with a gain phase analyzer [trademark: 4194 manufactured by Yokogawa Hewlett-Packard Co., Ltd.
A], and the above-mentioned non-contact magnetic marker is inserted into the pickup coil 201, and the frequency is 50 to 800 KH.
AC magnetic field is swept up to z, and the sixth harmonic is 130KH
z, the signal output at 620 KHz, which is the 29th harmonic, was measured.

Example 2 Magnetostrictive Metal Plate (B
2) Fe-Co-B having a resistivity of 130 μΩ-cm
Measurement of AC magnetic characteristics, preparation of non-contact magnetic marker, 130 KHz of 6th harmonic, in the same manner as in Example 1 except that Si-based metoglass “2605CO” (Allied Chemical Co., thickness 26 μm) was used. 62 of the 29th harmonic
The signal output was measured at 0 KHz.

Comparative Example 1 Magnetostrictive Metal Plate (B
As 3), Fe-B-Si having a resistivity of 125 μΩ-cm
Measurement of AC magnetic characteristics, preparation of non-contact magnetic marker, 130 KHz of 6th harmonic, in the same manner as in Example 1 except that C-type metoglass "2605SC" (manufactured by Allied Chemical Co., thickness 30 μm) was used. 620 of the 29th harmonic
The signal output was measured at KHz.

Comparative Example 2 Magnetostrictive Metal Plate (B
4) Fe-B-Si having a resistivity of 130 μΩ-cm
Measurement of AC magnetic characteristics and preparation of non-contact magnetic marker were conducted in the same manner as in Example 1 except that the system metgrass “2605S2” (manufactured by Allied Chemical Co., thickness 31 μm) was used.
6th harmonic 130KHz, 29th harmonic 620KH
The signal output at z was measured.

Comparative Example 3 Magnetostrictive Metal Plate (B
5) Fe-B-Si having a resistivity of 130 μΩ-cm
Example 1 except that a Cr-based metoglass "2605S3A" (manufactured by Allied Chemical Co., thickness 26 μm) was used.
In the same manner as above, measurement of AC magnetic characteristics, creation of non-contact magnetic marker, 6th harmonic 130KHz, 29th harmonic 6
The signal output was measured at 20 KHz.

Hereinafter, in the markers measured in Examples 1 and 2 and Comparative Examples 1 to 3, hysteresis loss derived from each metal plate (B), resistivity of each metal plate (B), and each marker signal at the resonance frequency. The output intensity is shown in Table 1.

[0062]

[Table 1]

In Table 1, the hysteresis loss is 5 J /
The marker using a metal plate having a magnetostrictive property exceeding m ³ has a low signal output at 130 KHz and 620 KHz,
In addition, the signal output decreases as the frequency increases,
It can be seen that the second harmonic cannot be detected.

FIG. 5 shows a hysteresis curve when an alternating magnetic field having a frequency of 1 KHz and a maximum magnetic field strength of 0.25 oersted was applied to the metal plate (B1) measured in Example 1. Similarly to FIG. 5, FIG. 6 to FIG.
And metal plates measured in Comparative Examples 1 to 3 (B2 to B5)
Shows a hysteresis curve when an alternating magnetic field having a frequency of 1 KHz and a maximum magnetic field strength of 0.25 oersted is applied to the.

FIG. 10 shows a graph of 6 when the AC magnetic field was swept up to the frequency of 50 to 800 KHz measured in Example 1.
The detection result of the signal of the next harmonic at 130 KHz is shown.
Similarly to FIG. 10, when the AC magnetic field is swept up to the frequencies 50 to 800 KHz measured in Example 2 and Comparative Examples 1 to 3 in FIGS.
The detection results of the signal at are shown.

FIG. 15 shows 2 when the AC magnetic field was swept up to the frequency of 50 to 800 KHz measured in Example 1.
The detection results of the signal at 620 KHz of the 9th harmonic are shown. Similarly to FIG. 15, the frequencies 50 to 800 KH measured in Example 2 and Comparative Examples 1 to 3 in FIGS.
620 of the 29th harmonic when the AC magnetic field is swept up to z
The detection result of the signal in KHz is shown.

FIG. 20 is a graph showing the relationship between the resistivity of each magnetostrictive metal plate used in Examples 1-2 and Comparative Examples 1-3 and the signal output at 620 KHz at the 29th harmonic. showed that.

Further, in FIGS. 10 to 19, the hysteresis loss exceeds 5 J / m ³ and the resistivity is 135 μΩ-c.
It is understood that the sharpness of the response signal at the resonance frequency of the marker using the metal plate having a magnetostrictive property of less than m further decreases as the frequency increases.

In FIG. 20, the resistivity is 135 μΩ.
It can be seen that the marker using a metal plate having a magnetostriction of less than −cm has a small signal output at 620 kHz and a low signal output at a high frequency.

In the above examples and comparative examples, the non-contact magnetic marker having a size of 5 mm × 105 mm has been described, but it may have a general size of 54 mm × 85 mm. Further, in the present embodiment, an example in which the pickup coil is inserted in the exciting coil is shown.
It goes without saying that the detection system can be created by increasing the current flowing through the exciting coil and making the exciting coil and the pickup coil face each other.

[0071]

The marker for an electronic article monitoring system of the present invention comprises a magnetostrictive metal plate having a hysteresis loss of 0.05 to 5 J / m ³ in an alternating magnetic field having a frequency of 1 KHz and a maximum magnetic field of 0.25 oersteds. Since it is used, by improving the signal strength and sharpness at the resonance frequency, it is possible to identify higher harmonic signals and increase the amount of information recorded on the data carrier.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a basic configuration of a magnetic marker that mechanically resonates at a frequency selected in advance with respect to an incident AC magnetic field having a frequency that fluctuates in a detection region.

FIG. 2 shows a state in which a hard magnetic metal plate having a length L is magnetized into n equal parts, and shows an example in which a bias magnetic field is applied to the magnetostrictive metal plate used in the present invention having a length L. It is a schematic diagram.

FIG. 3 is a schematic diagram showing a normal magnetic recording writing method as a method of magnetizing a hard magnetic metal plate (hard magnetic material).

FIG. 4 is a schematic diagram showing a system for non-contactly detecting identification information corresponding to magnetic recording of a non-contact magnetic marker having a magnetostrictive metal plate.

FIG. 5 shows a magnetostrictive metal plate (B1) having a frequency of 1 KHz and a maximum magnetic field strength of 0.25 measured in Example 1.
It is the figure which showed the hysteresis curve when the alternating magnetic field of Oersted is added.

FIG. 6 shows a magnetostrictive metal plate (B2) having a frequency of 1 KHz and a maximum magnetic field strength of 0.25 measured in Example 2.
It is the figure which showed the hysteresis curve when the alternating magnetic field of Oersted is added.

FIG. 7 shows a magnetostrictive metal plate (B3) having a frequency of 1 KHz and a maximum magnetic field strength of 0.25 measured in Comparative Example 1.
It is the figure which showed the hysteresis curve when the alternating magnetic field of Oersted is added.

FIG. 8 shows a magnetostrictive metal plate (B4) having a frequency of 1 KHz and a maximum magnetic field strength of 0.25 measured in Comparative Example 2.
It is the figure which showed the hysteresis curve when the alternating magnetic field of Oersted is added.

9 is a magnetostrictive metal plate (B5) having a frequency of 1 KHz and a maximum magnetic field strength of 0.25 measured in Comparative Example 3. FIG.
It is the figure which showed the hysteresis curve when the alternating magnetic field of Oersted is added.

FIG. 10 shows the frequency of a marker using a magnetostrictive metal plate (B1) measured in Example 1, which is 50 to 800.
130th of 6th harmonic when AC magnetic field is swept up to KHz
It is the figure which showed the detection result of the signal in KHz.

11 is a frequency range of 50 to 800 of a marker using a magnetostrictive metal plate (B2) measured in Example 2. FIG.
130th of 6th harmonic when AC magnetic field is swept up to KHz
It is the figure which showed the detection result of the signal in KHz.

FIG. 12 is a frequency range of markers 50 to 800 measured using a metal plate (B3) having magnetostriction measured in Comparative Example 1.
130th of 6th harmonic when AC magnetic field is swept up to KHz
It is the figure which showed the detection result of the signal in KHz.

13 is a frequency range 50 to 800 of a marker using a metal plate (B4) having magnetostriction, measured in Comparative Example 2. FIG.
130th of 6th harmonic when AC magnetic field is swept up to KHz
It is the figure which showed the detection result of the signal in KHz.

FIG. 14 shows frequencies of markers 50 to 800 using a magnetostrictive metal plate (B5) measured in Comparative Example 3.
130th of 6th harmonic when AC magnetic field is swept up to KHz
It is the figure which showed the detection result of the signal in KHz.

FIG. 15 is a frequency range 50 to 800 of a marker measured using a metal plate (B1) having magnetostriction measured in Example 1.
62 of the 29th harmonic when the AC magnetic field was swept up to KHz
It is the figure which showed the detection result of the signal in 0 KHz.

16 is a frequency range 50 to 800 of a marker using a metal plate (B2) having magnetostriction measured in Example 2. FIG.
62 of the 29th harmonic when the AC magnetic field was swept up to KHz
It is the figure which showed the detection result of the signal in 0 KHz.

FIG. 17 is a frequency range 50 to 800 of a marker using a magnetostrictive metal plate (B3) measured in Comparative Example 1.
62 of the 29th harmonic when the AC magnetic field was swept up to KHz
It is the figure which showed the detection result of the signal in 0 KHz.

FIG. 18 is a frequency range 50 to 800 of a marker using a magnetostrictive metal plate (B4) measured in Comparative Example 2.
62 of the 29th harmonic when the AC magnetic field was swept up to KHz
It is the figure which showed the detection result of the signal in 0 KHz.

FIG. 19 shows the frequency of a marker using a magnetostrictive metal plate (B5) measured in Comparative Example 3, which is 50 to 800.
62 of the 29th harmonic when the AC magnetic field was swept up to KHz
It is the figure which showed the detection result of the signal in 0 KHz.

FIG. 20 shows the resistivity of each magnetostrictive metal plate used in Examples 1 and 2 and Comparative Examples 1 to 3, and the marker obtained using each of the metal plates at 620 KHz at the 29th harmonic. It is the figure which showed the graph showing the relationship of a signal output.

[Explanation of symbols]

 1 Hard Magnetic Metal Plate (A) 2 Magnetostrictive Metal Plate (B) 3 Non-Magnetic Enclosure 100 Device 101 Oscillator 102 Output Amplifier 103 Excitation Coil 200 Device 201 Pickup Coil 202 Spectrum Analyzer

Claims (2)

[Claims] 1. A hard magnetic metal plate (A) and, in the state where the metal plate (A) is magnetized, mechanically resonates at a predetermined frequency in an incident AC magnetic field having a varying frequency to generate a magnetic flux density and In the state where the magnetic permeability changes and it is not magnetized, it does not resonate at the predetermined frequency, the magnetic flux density and the magnetic permeability do not change, and the metal plate (B) having magnetostriction and the metal plate (B) are The metal plate (A) is made of a laminated material that is mechanically resonated, and when the metal plate (A) is magnetized, the magnetic flux density or magnetic permeability changes with respect to the incident AC magnetic field. The metal plate (A) is divided and magnetized so as to have a plurality of magnetized sections, and the N pole of one of the two adjacent sections, and The N pole of the other adjacent section is less Even in the electronic article surveillance system marker which is divided magnetized so as to face the metal plate having a magnetostrictive (B) is, in the AC magnetic field having a frequency of 1KHz and the maximum magnetic field 0.25 Oe, 0.05
A marker for an electronic article monitoring system, which is a magnetostrictive metal plate having a hysteresis loss of 5 J / m ³ . 2. A magnetostrictive metal plate (B) has a frequency of 1
A magnetostrictive metal plate having a hysteresis loss of 0.05 to 5 J / m ³ and a resistivity of 135 to 200 μΩ-cm in an alternating magnetic field of KHz and a maximum magnetic field of 0.25 oersted. The described marker.