JPH0896100A - Magnetic recording medium and information reading method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention has a main purpose to significantly enhance the security of a medium and the reading property of information. According to the present invention, a plurality of magnetic marks made of a semi-hard magnetic material are provided in the vicinity of an amorphous magnetostrictive ribbon having a transmitting function, which is arranged in a vibrating state on a support.
This magnetic mark is magnetized with an arbitrary magnetizing pattern so that the peak of the magnetostrictive vibration resonance point of the amorphous magnetostrictive ribbon becomes a predetermined resonance frequency, and when reading information, an AC magnetic field is applied to the magnetic recording medium. To generate mechanical vibration (magnetostrictive vibration) of the amorphous magnetostrictive ribbon,
Information is read in a non-contact manner by detecting the transmission (resonance frequency) of the peak of the magnetostrictive vibration resonance point of the amorphous magnetostrictive ribbon according to the magnetization pattern in the alternating magnetic field.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium such as a magnetic card and an information reading method thereof, and in particular, by using a magnetic mark and a reading method different from conventional magnetic marks, the security of the medium and The present invention relates to a magnetic recording medium having a markedly improved information reading characteristic and a method for reading the information.

[0002]

2. Description of the Related Art In recent years, in our social life, magnetic recording media provided with a magnetic recording portion using a magnetic recording material are, for example, magnetic cards, magnetic tickets, magnetic commuter passes, magnetic coupons, magnetic sheets, etc. Has been widely used as a form of. In this magnetic recording medium, magnetic recording / reproduction is performed by using a magnetic head, an MR sensor, or the like in the magnetic recording portion, and information is recorded on them by the magnetization direction of the magnetic substance. Further, as such a magnetic recording medium,
Recently, magnetic marks are often provided for the purpose of improving the security of the medium.

FIG. 5 is a sectional view showing a structural example of a magnetic card provided with magnetic marks, which is represented by a prepaid card of this type.

That is, as shown in FIG. 5, a magnetic card is usually formed on a non-magnetic substrate 5 having a thickness of 100 to 250 μm.
1, a magnetic recording layer having a thickness of 10 to 15 μm is provided on the entire surface by a method such as whole surface coating, partial coating, or tape transfer. Also,
A magnetic bar 52 which is a magnetic mark, a dummy bar 53, a concealing layer 54, and the like are laminated between the protective layer 55 which is a top coat. In addition to this, a thermal recording layer, a rewrite recording layer, or the like may be provided. In this case,
The number of layers and the types of layers are determined by the required output and required characteristics of the magnetic card.

Here, the magnetic bar code, which is a magnetic mark, is a combination of a magnetic bar 61 containing a magnetic material and a dummy bar 62 containing no magnetic material, as shown in FIG. 6A. In general, the difference between the two is read by a magnetic sensor for security.

In this case, there are two types of reading methods depending on the characteristics of the magnetic material used.

That is, when a magnetic material having a low coercive force is used, a bias magnetic field is applied when reading with a magnetic sensor. If a semi-hard material with a relatively high coercive force is used as the magnetic material, the bar that has been magnetized in advance can be read by the magnetic sensor as it is, and the bias magnetic field can be changed as in the former case. It is also possible to read while applying.

As the output of the magnetic sensor, for example, as shown in the read output waveform in FIG. 6B, the output voltage can be obtained when the magnetic bar 61 is present, and the output can be obtained at the dummy bar 62. Therefore, the electric pattern obtained from the whole is used as fixed information such as the card ticket type and the issuing office.

Recently, in order to enhance the security of the magnetic bar, magnetic bars having different coercive forces may be combined (for example, "Japanese Patent Laid-Open No. 63-133321" or "Japanese Patent Laid-Open No. 63-308245"). , Combining magnetic bars with different amounts of magnetization (see, for example, "JP-A-63-
No. 223892 "), or a combination of magnetic bars using magnetic materials having different Curie points (see, for example," JP-A-62-
No. 147191 ”) has been proposed.

These are fixed information different from the magnetic information in the ordinary magnetic recording layer, and in general, providing a magnetic bar code on a magnetic card is nothing but providing security.

However, the conventional magnetic bar code as a magnetic mark basically only determines whether or not a bar using a magnetic material and a bar not using a magnetic material are mixed. Is a very simple one. The presence / absence of such a magnetic material can be easily distinguished by using a commercially available magnetic fluid. Therefore, it cannot be said that the effect of anti-counterfeiting is so great. , Security is low.

Further, in reading information, it is necessary to use a contact type or a super-proximity type (for example, 0.1 mm or less) magnetic head, a magnetic sensor, or the like, and therefore the distance between the magnetic mark and the magnetic sensor. Depending on the size of the output of the obtained signal, or the magnetic sensor cannot read the signal of the medium due to foreign matter such as dust or dirt (dusts coming out of the magnetic recording medium due to the scanning of the magnetic sensor). I have a problem.

Furthermore, since the information obtained by reading the magnetic mark provided on the medium is completely fixed information, it is difficult to deal with simple alterations such as cutting and pasting.

[0014]

As described above, the magnetic mark provided on the conventional magnetic recording medium has not only low security but also poor information reading characteristics.

The present invention has been made to solve the above problems, and provides a magnetic recording medium and a method of reading the same, which can remarkably improve the security of the medium and the information reading characteristic. The purpose is to provide.

[0016]

In order to achieve the above object, first, the magnetic recording medium of the invention according to claim 1 is arranged in a vibrating state not fixed to a support, and at least as a transmitter. Amorphous magnetostrictive ribbon having a function and a support, which are arranged in the vicinity of the amorphous magnetostrictive ribbon, and are magnetized in an arbitrary magnetizing pattern such that the magnetostrictive vibration resonance point peak of the amorphous magnetostrictive ribbon has a predetermined resonance frequency. , A plurality of magnetic marks made of a semi-hard magnetic material.

On the other hand, in the information reading method of the magnetic recording medium according to the second aspect of the present invention, an alternating magnetic field is applied to the magnetic recording medium to mechanically vibrate the amorphous magnetostrictive ribbon (magnetostrictive vibration).
Is generated and information is read in a non-contact manner by detecting the transmission (resonance frequency) of the magnetostrictive vibration resonance point peak of the amorphous magnetostrictive ribbon according to the magnetization pattern in the applied AC magnetic field.

[0018]

Therefore, in the magnetic recording medium and the information reading method thereof of the present invention, the magnetic mark made of a semi-hard magnetic material having an amorphous magnetostrictive ribbon in the vicinity thereof is read in an alternating magnetic field as the magnetic mark. The magnetic pattern information including the non-contact magnetic polarization can be read as the information unique to the medium.

As a result, it is possible to improve a reading error due to insufficient output due to spacing or dust inclusion, as compared with the conventional magnetic mark, so that the information reading characteristic can be remarkably improved.

Since the method of reading information is new and it is necessary to distinguish the polarity of magnetization of the magnetic mark, it is expected that the security of the medium will be significantly improved.

Furthermore, by arranging the amorphous magnetostrictive ribbon on the substrate itself in an embedded manner, it is extremely effective for simple modification such as cutting and pasting.

[0022]

EXAMPLES Recently, for example, "WO92 / 12402 publication"
As disclosed in, a semi-hard magnetic material used in a magnetic recording medium and an amorphous magnetostrictive ribbon are combined, the magnetic pattern recorded in the semi-hard magnetic material is used as a bias magnetic field, and the A magnetic recording medium has been developed which can be read in a non-contact manner using the detected resonance point peak of the amorphous magnetostrictive ribbon as information.

This information recording medium comprises at least an amorphous magnetostrictive ribbon having a function as an oscillator and a magnetic recording body made of a semi-hard magnetic material for generating a bias magnetic field.

That is, the concept of transmission of this information recording medium is that when a bias magnetic field is applied along the magnetostrictive curve of the amorphous magnetostrictive ribbon and an alternating magnetic field is superimposed, the amorphous magnetostrictive ribbon generates magnetostrictive vibration along the magnetostrictive curve.
This applied AC magnetic field is received by the antenna as a transmission signal from the amorphous magnetostrictive ribbon. This transmission signal is the recorded information on the information recording medium, and the information can be read by non-contact (possible even at a distance of about 1 m). Then, normally, in information communication, a resonance point depending on the shape of the amorphous magnetostrictive ribbon is used to obtain a large output.

The present invention is based on the above concept, and a plurality of magnetic marks made of a semi-hard magnetic material are provided in the vicinity of an amorphous magnetostrictive ribbon having a transmitting function, which is arranged in a vibrating state on a support. This magnetic mark is magnetized with an arbitrary magnetizing pattern so that the magnetostrictive vibration resonance point peak of the amorphous magnetostrictive ribbon becomes a predetermined resonance frequency, and when reading information, the magnetic recording medium is An AC magnetic field is applied to generate mechanical vibration (magnetostrictive vibration) of the amorphous magnetostrictive ribbon, and the magnetostrictive vibration resonance point peak of the amorphous magnetostrictive ribbon according to the magnetization pattern in the AC magnetic field is transmitted (resonance frequency). Is detected in a non-contact manner to detect magnetic pattern information including the polarity of magnetization.

An embodiment of the present invention based on the above concept will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view showing a structural example of a magnetic card provided with a magnetic mark according to the present invention.

That is, the magnetic card of this embodiment is shown in FIG.
, A plastic case 11 that is a support for supporting the medium, an amorphous magnetostrictive ribbon 12,
Basically, a plurality of (eight in this embodiment) magnetic marks (magnetic bar codes in this embodiment) 13 made of a semi-hard magnetic material are combined. Further, a concealing layer 14 and a protective layer 15 are sequentially laminated on the magnetic mark 13 so as to conceal and protect the magnetic mark 13.

Here, the amorphous magnetostrictive ribbon 12 is
It is arranged in a space provided in the plastic case 11 as shown in the figure in a vibrating state that is not fixed and has at least a function as a transmitter.

Further, the magnetic mark 13 is arranged on the plastic case 11 close to the amorphous magnetostrictive ribbon 12, and the magnetostrictive vibration resonance point peak of the amorphous magnetostrictive ribbon 12 is arbitrarily set to have a predetermined resonance frequency. It is magnetized with the magnetization pattern.

Then, an AC magnetic field is applied to the magnetic card to mechanically vibrate the amorphous magnetostrictive ribbon 12 (magnetostrictive vibration).
Is generated, and the transmission of the peak of the magnetostrictive vibration resonance point (resonance frequency) of the amorphous magnetostrictive ribbon 12 according to the magnetization pattern in the applied AC magnetic field is detected (resonance frequency) to read the information in a non-contact manner. ing.

As the amorphous magnetostrictive ribbon 12, Fc-Ni-Mo-B having a high magnetic permeability and magnetostriction is generated.
System, Fe-B-Si system, Fe-B-Si-C system, Fe-
A Co—B—Si-based alloy or the like can be formed into a ribbon shape having a thickness of 10 to 50 μm as an amorphous material by the ultraquenching method. If necessary, post-processing such as magnetic field annealing may be performed in order to improve the signal detection sensitivity.

The semi-hard magnetic material of the magnetic mark 13 is an important element in the present invention. And as this material, for example, Cu-Ni-Fe alloy, Cu-N
i-Co alloy, Fe-Cr-Co alloy, Fe-Co-V
Alloy, Fe-Ni-Cr alloy, Fe-Mn alloy, Co-
A magnetic alloy such as a Pt alloy may be drawn into a plate shape and cut out and used.

Rare earth-cobalt magnets such as R-Co5, Ba-ferrite magnets, Sr-ferrite magnets, alnico magnets and the like can also be used.

Further, as a matter of course, as used in a magnetic tape or the like, a magnetic powder, for example, Ba-ferrite, Sr-ferrite, γ-iron oxide powder or the like dispersed in a binder to form a paint is used as a plastic. It is possible to use those printed on the base material, or those obtained by vapor deposition and transfer of a magnetic material.

In the present invention, the magnetic mark 13 made of a semi-hard magnetic material preferably has a coercive force of 300 Oe or more in order to ensure recording stability.

FIG. 2 is an overall perspective view showing a structural example of a magnetic card provided with a magnetic mark according to this embodiment.

In FIG. 2, a magnetic recording track 21 capable of ordinary magnetic recording is provided by transferring a magnetic tape. The magnetic mark 13 is provided on a magnetic mark track 22 different from the magnetic recording track 21.

Next, an example of the information reading method of the magnetic card of the present embodiment having the above-mentioned structure will be described with reference to FIG.

FIG. 3 is a block diagram showing a configuration example of a reading device for reading information from a magnetic card provided with a magnetic mark according to this embodiment.

That is, in FIG. 3, the magnetic card 31
Are arranged between the transmitting coil 32 and the receiving coil 33 arranged to face each other. From the transmission coil 32,
A weak AC magnetic field that does not affect the magnetic recording of the magnetic card 31 is generated using the frequency modulation oscillator 34 as a power source.

The amorphous magnetostrictive ribbon 12 generates magnetostrictive vibration by the AC magnetic field applied from the transmitting coil 32, and when the frequency of the applied AC magnetic field and the magnetostrictive vibration resonance frequency of the amorphous magnetostrictive ribbon 12 match, the receiving coil. The magnitude of the magnetic field received by 33 takes a maximum.

The signals received by the receiving coil 33 and the signal from the frequency modulation oscillator 34, which is the AC power source of the transmitting coil 32, are input to the lock-in amplifier 35 and amplified, as reference signals. The decoder 36 decodes the signal.

In this case, the detectable resonance frequency of the magnetostrictive vibration resonance point peak of the amorphous magnetostrictive ribbon 12 differs depending on the pattern of the magnetic mark 13 and the pattern magnetized to the magnetic mark 13.

Therefore, the magnetic mark 13 is magnetized in an arbitrary magnetizing pattern so that the peak of the magnetostrictive vibration resonance point of the amorphous magnetostrictive ribbon 12 becomes a predetermined resonance frequency, and when reading information. , Magnetic card 31
An alternating magnetic field is applied to the magnetic field to generate magnetostrictive vibration of the amorphous magnetostrictive ribbon 12, and the oscillation (resonance frequency) of the resonance point peak of the magnetostrictive vibration of the amorphous magnetostrictive ribbon 12 corresponding to the magnetization pattern in the alternating magnetic field is detected. By doing
Magnetic pattern information including the polarity of magnetization can be read without contact.

Next, an example of an actually manufactured magnetic card 31 of this embodiment will be described.

That is, as the amorphous magnetostrictive ribbon 12, Metglas 2826MB (manufactured by Allied)
Was cut into a size of 40 × 5 × 0.03 mm. Then, first, by injection molding, a base 11 having a recess for disposing the amorphous magnetostrictive ribbon 12 in the central portion is made of ABS resin, and the amorphous magnetostrictive ribbon 12 is disposed in this recess to have a thickness of 0.2 mm. AB
The lid was covered with an S resin plate. At this time, the amorphous magnetostrictive ribbon 12 was in a state where it could freely vibrate without being subjected to treatment such as adhesion. It should be noted that the entire base 11 is about 1 m.
The thickness was m.

As the semi-hard magnetic material used for the magnetic mark 13, γ-iron oxide (300 Oe) 70 parts by weight Vinyl chloride-vinyl acetate copolymer resin 15 parts by weight Cyclohexanone 10 parts by weight Butyl cellosolve 5 parts by weight Using screen ink, sol thickness 20μm, 2
Using a 00-line / inch screen plate, a magnetic pattern 13 was formed by a screen printing method in a rectangle of 1 × 5 mm per bar. The film thickness in the dried state was about 10 μm.

Further, as the concealing layer 14, 30 parts by weight of aluminum paste, 60 parts by weight of polyester resin, 5 parts by weight of cyclohexanone, and 5 parts by weight of butyl cellosolve were used as a screen ink having a sol thickness of 4 μm and 300 lines / inch. The thickness was about 3 μm by the screen printing method.

Furthermore, as the protective layer 15, the ink is FDOP available from Toyo Ink Mfg. Co., Ltd.
The varnish was used to form a film having a thickness of about 2 μm by the UV dry offset printing method.

On the other hand, as the reading device, a coil having a diameter of 35 mm and 200 turns was made of a copper wire having a diameter of 0.4 mm as the transmitting coil 32 and the receiving coil 33. Then, the AC magnetic field modulated by the frequency modulation transmitter 34 to 50 to 300 kHz was transmitted using the transmission coil 32. At this time, the transmitting coil 32 and the receiving coil 3 facing each other
The distance from the magnetic card 31 was about 40 mm, and the magnetic field near the magnetic card 31 was a weak 0.1 Oe order.

FIG. 4 is a diagram showing an example of an output waveform of information reading in this prototype example.

That is, when the magnetic mark 13 is not magnetized at all, the magnetostrictive vibration resonance points of the amorphous magnetostrictive ribbon 12 are 54 kHz, 108 kHz, 162 kHz.
The resonance point peaks of z, 208 kHz and 257 kHz could be observed.

On the other hand, when the magnetic mark 13 is magnetized as a magnetic pattern with the N pole of the magnetic bar 41 and the S pole of the magnetic bar 48, only the resonance point peak of 108 kHz is obtained as shown in FIG. 4A. Was detected.

When the magnetic pattern is magnetized so that the magnetic bar 44 has the N pole and the magnetic bar 45 has the N pole, FIG.
As shown in (b), only the resonance point peak at 162 kHz could be detected.

Further, when magnetization is performed as a magnetic pattern with the N pole on the magnetic bar 43 and the S pole on the magnetic bar 46, 20
Only the resonance peak at 8 kHz could be detected.

Furthermore, magnetizing is performed as a magnetic pattern,
If the magnetic bar 42 is an N pole and the magnetic bar 47 is an N pole,
Only the resonance peak at 257 kHz could be detected.

The position of the magnetic mark 13 was appropriately adjusted in order to detect these resonance point peaks independently. Further, depending on the magnetization pattern, it is possible to detect a plurality of resonance point peaks. Furthermore, as the magnetization direction,
The sensitivity was better in the vertical direction than in the longitudinal direction.

As described above, in this embodiment, the base 11
Amorphous magnetostrictive ribbon 1 that is arranged in a freely vibrating state and is not fixed to the
2 and a semi-hard material which is arranged on the substrate 11 in the vicinity of the amorphous magnetostrictive ribbon 12 and which is magnetized in an arbitrary magnetizing pattern so that the peak of the magnetostrictive vibration resonance point of the amorphous magnetostrictive ribbon 12 becomes a predetermined resonance frequency. 8 made of magnetic material
The magnetic card 31 is provided with the individual magnetic marks 13, and when reading the information, an AC magnetic field is applied to the magnetic card 31 to generate magnetostrictive vibration of the amorphous magnetostrictive ribbon 12, and the applied AC is applied. Information is read in a non-contact manner by detecting the transmission (resonance frequency) of the peak of the magnetostrictive vibration resonance point of the amorphous magnetostrictive ribbon 12 according to the magnetization pattern in the magnetic field.

Therefore, as the magnetic mark, the magnetic mark 13 made of a semi-hard magnetic material provided in the vicinity of the amorphous magnetostrictive ribbon 12 is read in an alternating magnetic field to obtain a magnetic field including the magnetization polarity in a non-contact manner. The pattern information can be read as information unique to the medium.

As a result, it is possible to improve the reading error due to insufficient output due to spacing and the presence of dust, as compared with the conventional magnetic mark, and it is possible to remarkably improve the information reading characteristic.

Since the method of reading information is new and it is necessary to distinguish the polarity of magnetization of the magnetic mark 13, it is possible to expect a significant improvement in the security of the magnetic card 31. .

Further, since the amorphous magnetostrictive ribbon 12 is arranged in the substrate 11 itself in an embedded manner, it is extremely effective for simple modification such as cutting and sticking.

The present invention is not limited to the above embodiment, but can be implemented in the same manner as described below.

(A) In the above embodiment, the case where the magnetic marks 13 are all made of a magnetic material has been described, but the present invention is not limited to this, and a dummy is mixed so that only a specific resonance point peak is present. Of course, it is also possible to detect. In this case, the reading by the magnetic sensor can be performed in the same manner as the conventional one.

(B) In the above embodiments, the case where the present invention is applied to a magnetic card has been described. However, the present invention is not limited to this, and other forms such as a magnetic ticket, a magnetic commuter pass, a magnetic coupon ticket, a magnetic sheet, etc. The same effects can be obtained by applying the present invention to magnetic recording media as well.

[0067]

As described above, according to the present invention, an amorphous magnetostrictive ribbon which is not fixed to a support and is arranged in a vibrating state and which has at least a function as an oscillator, and a support close to the amorphous magnetostrictive ribbon. And a plurality of magnetic marks made of a semi-hard magnetic material, which are magnetized in any magnetization pattern so that the magnetostriction vibration resonance point peak of the amorphous magnetostriction ribbon has a predetermined resonance frequency, and When reading the information, an AC magnetic field is applied to the magnetic recording medium to generate mechanical vibration (magnetostriction vibration) of the amorphous magnetostrictive ribbon, and the amorphous magnetostriction according to the magnetization pattern in the applied AC magnetic field. Information is read in a non-contact manner by detecting the transmission of the peak of the magnetostrictive vibration resonance point of the ribbon (resonance frequency). Utility properties, as well as significantly magnetic recording medium and the information reading method capable of enhancing the reading characteristic information can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a magnetic card provided with a magnetic mark according to the present invention.

FIG. 2 is an overall perspective view showing an embodiment of the magnetic recording medium.

FIG. 3 is a block diagram showing a configuration example of a reading device for reading information from a magnetic card provided with a magnetic mark in the embodiment.

FIG. 4 is a diagram showing an example of an output waveform of information reading in the embodiment.

FIG. 5 is a cross-sectional view showing a configuration example of a conventional magnetic card provided with a magnetic mark.

FIG. 6 is a view showing an example of an output waveform of information reading of a conventional magnetic card provided with a magnetic mark.

[Explanation of symbols]

11 ... Substrate, 12 ... Amorphous magnetostrictive ribbon, 13 ... Magnetic mark made of semi-hard material, 14 ... Concealing layer, 15 ... Protective layer, 21 ... Track (magnetic transfer tape) for normal magnetic recording, 22 ... Magnetic mark track, 31 ... Medium, 3
2 ... Transmission coil, 33 ... Reception coil, 34 ... Frequency modulation oscillator, 35 ... Lock-in amplifier, 36 ... Decoder,
41-48 ... magnetic bar, 51 ... base, 52 ... magnetic bar,
53 ... Dummy bar, 54 ... Concealing layer, 55 ... Protective layer, 61
... magnetic bar, 62 ... dummy bar.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location G06K 19/10 G11B 5/00 Z 8841-5D (72) Inventor Ken Namikawa 4th Hisagahara, Ota-ku, Tokyo Chome 33-9

Claims (2)

[Claims] 1. An amorphous magnetostrictive ribbon which is not fixed to a support and which is arranged in a freely vibrating state and which has at least a function as a transmitter; and an amorphous magnetostriction which is arranged on the support in proximity to the amorphous magnetostrictive ribbon. A magnetic recording comprising a plurality of magnetic marks made of a semi-hard magnetic material, magnetized in an arbitrary magnetization pattern so that the peak of the magnetostrictive vibration resonance point of the ribbon has a predetermined resonance frequency. Medium. 2. An amorphous magnetostrictive ribbon which is not fixed to a support and which is arranged in a freely vibrating state and which has at least a function as an oscillator; and an amorphous magnetostriction which is arranged on the support in proximity to the amorphous magnetostrictive ribbon. In a method for reading information on a magnetic recording medium, which is magnetized with an arbitrary magnetizing pattern so that a magnetostriction vibration resonance point peak of a ribbon has a predetermined frequency, and a plurality of magnetic marks made of a semi-hard magnetic material, An AC magnetic field is applied to a magnetic recording medium to generate mechanical vibration (magnetostrictive vibration) of the amorphous magnetostrictive ribbon, and the magnetostrictive vibration of the amorphous magnetostrictive ribbon according to the magnetization pattern in the applied AC magnetic field. The feature is that the information is read in a non-contact manner by detecting the transmission of the resonance point peak (resonance frequency). Information reading method of a magnetic recording medium.