JPH09231302A - Magnetic marker and its reading method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extremely simply and inexpensively form a magnetic marker allowed to be contactlessly read out and increasing its recordable information quantity. SOLUTION: Magnetic patterns 11, 12 are collectively formed by screen printing so that their easily magnetized directions form a +45 deg. and -45 deg. angle from a scanning direction. When an excitation coil 23 magnetically excites these patterns 11, 12, induced electromotive force is generated in a detection coil 22 by a component bent by the pattern 11 or 12 and oriented in the same direction as the scanning direction or its reverse direction out of magnetically excited magnetic flux. The induced electromotive force depends upon an angle formed between the magnetic direction of the magnetic pattern and the scanning direction. Thereby a sign can be acquired by the polarity and voltage of the induced electromotive force generated in the coil 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic marker composed of a magnetic pattern formed on the surface of a recording medium, and more particularly, it can be read in a non-contact manner and has a large amount of information in the magnetic pattern. The present invention relates to a magnetic marker and its reading method.

[0002]

2. Description of the Related Art In recent years, recording media in which a large amount of information is recorded on a magnetic marker composed of a magnetic pattern are becoming widespread. Such recording media include, for example, magnetic cards and
There are magnetic tickets, magnetic commuter passes, magnetic coupons, and magnetic sheets. Such a magnetic marker shows various kinds of information about the medium, and is more resistant to dirt such as mud compared to the method using an optical bar code, so that it can be used in fields such as FA and physical distribution. Has been.

Of such recording media, for example, a magnetic card is usually formed by applying a magnetic recording layer having a thickness of about 10 to 15 μm on a non-magnetic substrate having a thickness of about 100 to 200 μm. Further, from the magnetic recording layer to the surface protective layer, as magnetic markers, a layer provided with a magnetic barcode, a concealing layer, a thermal printing layer and the like are laminated. The number of layers of each of these layers, the type of layers, etc. are set so as to suit the output required for the magnetic card, the characteristics, and the like. Here, the barcode is composed of a combination of a magnetic portion containing a magnetic substance and a non-magnetic portion not containing a magnetic substance in the magnetic recording layer, and the fixed information (for example, user ID or , Pattern information about the amount of money, issuing agency, etc.). This ensures security in the recording medium. Such a bar code BC is formed on the surface of the magnetic card at a position as shown in FIG. 10, for example. In the figure, for convenience of explanation, the barcode B
Although both the magnetic portion and the non-magnetic portion of C are shown in the figure, in reality, they cannot be discriminated with the naked eye unless a magnet viewer or the like is used as described later.

FIG. 11 is an enlarged sectional view taken along the line AA 'in FIG. As shown in this figure, in the magnetic card 70, a magnetic recording layer 72 is formed on a non-magnetic substrate 71, and a magnetic powder having a coercive force lower than that of the magnetic material used in the magnetic recording layer 72 is formed therein. The magnetic bar code portion 73 made of non-magnetic powder and the dummy bar code portion 74 made of non-magnetic powder are formed by offset printing, screen printing, or the like. Further, in a general magnetic card, a concealing layer 75 that conceals these magnetic / non-magnetic bar code portions, a protective layer 76 for protecting the surface, and the like are formed by similar printing or the like.

By the way, in this type of magnetic card, as a magnetic material forming the magnetic bar code portion 73,
Conventionally, the two types have been mainly used, and therefore, the reading method also differs as follows. That is,
The first type has a coercive force of the magnetic bar code portion 73 that does not affect the coercive force of the magnetic recording layer 72.
In addition, after forming a magnetic material having a coercive force sufficient for recording, writing / reading of recording is performed by the same method as that used for the magnetic recording layer. The magnetic material used in this case, for example, magnetite (Fe ₃ O ₄₎ and, gamma-iron oxide (γ-Fe ₂ O ₃₎ or the like. However, in the first type, the magnetically recorded magnetic bar code section 73 can be distinguished from the magnetic bar code section 73 and the dummy bar code section 74 by using a commercially available so-called magnet viewer or the like. Will end up. In order to prevent this, it is necessary to take measures such as degaussing after reading the information recorded in the magnetic bar code portion 73, but there is a disadvantage that the reading configuration is complicated and bloated. .

Then, in order to solve such a problem, a second type described below has been devised. That is, the second type is a carbonyl iron powder having a low coercive force of 30 Oe or less, Mn-Zn ferrite, or the like, which is a magnetic material of the magnetic bar code portion 73, which cannot be detected by a magnet viewer or the like. It is used (see, for example, Japanese Patent Application Laid-Open No. 1-109524).

Then, the magnetic bar code portion 73 formed by the second type is read by the following method. That is, first, a direct current is supplied to the reading magnetic head as a bias, and a weak direct current magnetic field that does not affect magnetic recording is applied to the magnetic bar code portion 73. Then, the DC magnetic field magnetizes the magnetic bar code portion 73 formed of a magnetic material having a low coercive force, and the reading magnetic head simultaneously reads the magnetic bar code portion 73, thereby obtaining an output signal waveform as shown in FIG. In this case, since the dummy bar code portion 74 is not magnetized, there is no corresponding output. Therefore, by combining the magnetic bar code unit 73 and the dummy bar code unit 74, an output signal waveform according to a specific pattern can be obtained, and this waveform is analyzed by a subsequent analysis circuit to be encoded with the specific pattern. You can get information.

In addition to the above-mentioned first and second types, a method of combining magnetic materials having different coercive forces in order to ensure security (for example, JP-A-63-133).
No. 321, JP-A-63-308724) or a method of combining magnetic bar codes having different magnetization amounts (see, for example, JP-A-63-223892),
There are various methods such as a method using magnetic materials having different Curie points (see, for example, Japanese Utility Model Laid-Open No. 62-147191). The information indicated by the barcode by these methods is fixed information different from the usual magnetic recording method, and generally providing a magnetic barcode on a magnetic card is nothing but ensuring of security.

On the other hand, the magnetic marker has been put to practical use other than the use for a card (for example, Japanese Patent Laid-Open No. 1-2336).
No. 75 and JP-A-1-233688.
A barcode composed of such a magnetic marker records data in an array of bar-shaped metals. The magnetic marker is formed by a permanent magnet that generates a DC magnetic field and an MR (magnetic resistance) sensor that detects the amount of magnetic flux. Can be read without contact. As a result, the magnetic marker functions sufficiently even if it is soiled by mud or the like, so that the drawbacks of using a general optical barcode are eliminated.

As described above, many magnetic markers are currently used, and most of them are used as magnetic bar codes.

[0011]

However, since most of the conventional magnetic markers are read by a contact type, the reading performance is deteriorated when dust or dirt is generated on the magnetic marker. It had drawbacks. Further, even if the MR sensor is read in a non-contact manner, the presence or absence of magnetic flux and the binary value of the code are finally associated with each other, so that the amount of recordable information is extremely small. The present invention has been made in view of the above background, and an object thereof is a magnetic marker that can be read in a non-contact manner and that can increase the amount of recordable information, and the magnetic marker. It is to provide a reading method.

[0012]

In order to solve the above-mentioned problems, in the invention described in claim 1, the magnetic pattern is formed so that the easy magnetization direction forms a predetermined angle with the scanning direction. The magnetic marker is characterized in that it is encoded by the angle and the magnetic pattern is arranged in the scanning direction corresponding to the code to be recorded. According to the invention of claim 2, in the invention of claim 1, the angle is -45 degrees or +45 degrees.
Is a degree and is characterized in that each corresponds to a code "0" or "1". In the invention according to claim 3, in the invention according to claim 1, the angle is in a range of −45 degrees to +45 degrees, and corresponds to a value associated in advance in the range. It has a feature. According to a fourth aspect of the invention, in the invention according to any one of the first to third aspects, a magnetic ink is printed on the substrate to form the magnetic pattern. According to a fifth aspect of the invention, in the invention according to any one of the first to third aspects, a foil made of a magnetic material is formed by deposition, and the foil is transferred to a substrate to form the magnetic pattern. It is characterized by that. In the invention according to claim 6, the magnetic pattern is formed so that the easy magnetization direction forms a predetermined angle with the scanning direction, and the magnetic pattern is arranged in the scanning direction corresponding to the code to be recorded. Inducing electromotive force is generated by a process of magnetically exciting the magnetic pattern provided and a component of the magnetically excited magnetic flux that is bent by the magnetic pattern and is in the same or opposite direction to the scanning direction. And a step of obtaining a code corresponding to the arrangement of the time pattern by the induced electromotive force.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing the configuration of a magnetic recording medium to which the magnetic marker of this embodiment is applied. On the upper surface of the magnetic recording medium 10 shown in this figure, a bar code BC consisting of five magnetic patterns 11 and 12, that is, a magnetic marker is formed. The magnetic patterns 11 and 12 have a code “0”,
This corresponds to "1" and is composed of a large number of arrays of magnetic material pieces having high magnetic permeability. The angle formed between the strip direction (easy magnetization direction) of each magnetic piece and the scanning direction is +45 degrees for the magnetic pattern 11 when the clockwise direction is positive in the figure, and the magnetic pattern 1
2 is -45 degrees.

Next, the structure for reading the bar code BC formed on the magnetic recording medium 10 described above will be described with reference to FIG.
This will be described with reference to FIG. As shown in this figure, at the time of reading, the magnetic recording medium 10 is scanned by the detection element 20 at intervals d without contact, and at that time, the bar code BC is read. In this case, even if the magnetic recording medium 10 is transported and read by the fixed detection element 20,
On the contrary, with the magnetic recording medium 10 fixed, the detection element 20
May be configured to scan. That is, as long as relative movement in the scanning direction shown in the drawing occurs between the magnetic recording medium 10 and the detection element 20, any configuration may be used in this embodiment.

Here, the detection element 20 is composed of a core 21, a detection coil 22 and an excitation coil 23, as shown in the figure. Detection coil 22 and excitation coil 23
As shown in FIG. 3, each is formed in a rectangular 8-shape, and they are orthogonal to each other and are separated for the sake of explanation in the drawing, but their forming planes are substantially the same. In order to increase the detected magnetic flux of the detection coil 22 and the generated magnetic flux of the excitation coil 23, a cross-shaped groove is formed in the core 21 as shown in FIG. The excitation coil 23 is wound, and the core 21 is made of a high magnetic permeability material such as ferrite. Further, the detection coil 22 and the excitation coil 23 have one turn for the sake of explanation in the figure, but normally have a plurality of turns in order to increase the magnetic flux.

Next, how the information of the bar code BC is obtained in the reading configuration will be described. First, assuming that a current is applied to the excitation coil 23 in the direction shown in FIG. 3, the magnetic field generated by this current causes a magnetic flux φ _P as shown in the figure on the lower surface of the excitation coil 23. At this time, when the magnetic marker is not formed on the upper surface of the magnetic recording medium 10, the same magnetic flux φ _P causes the magnetic recording medium 10 to be viewed from above in FIG.
Occurs in the direction perpendicular to the scanning direction. In contrast, for example, in a portion where the magnetic pattern 11 is formed, as shown in FIG. 4 (b), the magnetic field generated is bent in accordance with the strip direction of the magnetic pattern 11, the magnetic flux phi _A according to the bending magnetic field Occur. The magnetic flux φ _A is
It can be decomposed into a magnetic flux φ _P 'having a component in the direction perpendicular to the scanning direction and a magnetic flux φ _B having a component in the direction opposite to the scanning direction. Therefore, magnetic flux having a component in the scanning direction is newly generated by magnetic excitation by the excitation coil 23. On the other hand, in the place where the magnetic pattern 12 is formed, a magnetic flux in the direction opposite to the magnetic flux φ _B is generated for the same reason. In addition, in the portion where the magnetic marker is not formed, the magnetic flux φ _P goes straight in the direction perpendicular to the scanning direction (see FIG. 4A), so that the magnetic flux having a component in the scanning direction does not occur.

By the magnetic pattern 11, the magnetic flux φ _B
When this occurs, a magnetic field is generated by the magnetic flux φ _B in a direction perpendicular to the scanning direction, as shown in FIG.
Since the detection coil 22 moves relative to this magnetic field in the scanning direction, an induced electromotive force is generated in the detection coil 22 in the direction shown in the figure. Further, with respect to the magnetic pattern 12, since the direction of the magnetic field is opposite to the direction shown in the figure, induced electromotive force in the opposite direction is generated. In addition, in a portion where the magnetic marker is not formed, an induced electromotive force is not generated in the detection coil 22 because there is no magnetic flux having a scanning direction component due to the magnetic field generated by the excitation coil 23.

Therefore, a current is passed through the excitation coil 23 to move the detection element 20 relative to the magnetic recording medium 10 so as to determine whether or not there is an induced electromotive force generated in the detection coil 22 and, if any, the voltage (and polarity) thereof. ) Is detected, the information corresponding to the barcode BC can be acquired.

By the way, it is not preferable to keep the direct current flowing through the excitation coil 22 because it causes a magnetization phenomenon in the peripheral portion, and the output voltage is small. Therefore, in the present embodiment, an alternating current is used as the excitation signal in the excitation coil 22,
This is intended to generate an alternating magnetic field. An example of such a configuration is shown in FIG. In this example, the frequency of the excitation signal is 100 kHz, and the lock-in amplifier 30 obtains the voltage V _out that is obtained by rectifying the output of the detection coil 22 in synchronization with the excitation signal.

The relationship between the output voltage V _out and the position of the detecting element 20 is shown in FIG. As shown in this figure, even if a configuration is used in which an alternating current is passed through the excitation coil 23, it is possible to obtain information corresponding to the barcode BC by detecting the presence or absence of the V _out signal and, if there is, the polarity thereof. In the example shown in this figure, the magnetic patterns 11, 12, 1
It is possible to obtain the codes “0”, “1”, “1”, “1”, “0” by the voltage V _out corresponding to 2, 12, 11.

Now, in the above-described embodiment, the strip direction of the magnetic material forming the magnetic marker is set to the detection element 2
The scanning direction was set to +45 degrees and -45 degrees. Here, in FIG. 8A, the angle θ of the direction of the magnetic strip with respect to the scanning direction ranges from −90 degrees to +90.
The characteristic of the voltage V _out when the voltage is changed up to 10 degrees is shown in FIG. As shown in this figure, the output voltage V
_out becomes maximum when the angle θ is +45 degrees and −45 degrees. Therefore, also in the present embodiment, the angle θ is set to +45 degrees and −4 for the magnetic patterns 11 and 12, respectively.
It was set to 5 degrees.

Conversely, as can be seen from FIG. 8B, when the angle θ changes, the voltage V _out also changes continuously. In particular, when −45 ≦ θ ≦ 45, the angle θ is uniquely determined if the voltage V _out is determined. Therefore, the angle θ
By preliminarily associating the voltage V _out with the voltage V _out , not only digital data with the codes “0” and “1” but also continuous analog data and multi-valued data can be handled. For example, the angle θ is −45 degrees, −30 degrees, +
30 degrees and +45 degrees are coded as "00",
Corresponds to "01", "10" and "11". Here, when the voltage V _out when the angle θ is +45 degrees is normalized to be “1”, the output voltage V _out is “−1”,
When "-0.5", "0.5", and "+1", by setting the code to "00", "01", "10", and "11", 2 bits for one bar Information can be assigned.

Therefore, according to such a magnetic marker, not only the contactless reading but also the analog data and the multi-valued data can be shown by one bar. Therefore, the amount of recordable information can be dramatically increased.

In addition, in the magnetic marker according to the present embodiment, since the excitation magnetization at the time of reading is an alternating current, the scanning speed is higher than that of the conventional bar code system in which the bar code width corresponds to the code. The barcode can be read stably without depending on it.

[0025]

EXAMPLES Next, specific examples of the magnetic recording medium will be described. FIG. 9 is a cross-sectional view showing the structure of the magnetic recording medium according to this example. The magnetic recording medium 10 according to this example has a magnetic pattern 1 for a PET substrate.
This is to collectively form the magnetic substance pieces 1 and 12 by screen printing with magnetic ink. As the magnetic ink, it is suitable to use Mn-Zn ferrite as a magnetic material, a magnetic powder of high magnetic permeability such as iron alloy magnetic powder, magnetite, or carbonyl iron powder in a vinyl chloride vinyl acetate binder. That is, in this embodiment, the magnetic ink formed by printing is applied to the magnetic patterns 11 and 1.
It acts as one of the magnetic substance pieces in 2. According to this embodiment, the magnetic recording medium can be manufactured at an extremely low cost.

In addition, various methods such as gravure, offset, and the like, in which a magnetic piece of the magnetic patterns 11 and 12 corresponding to a small magnetic piece is formed by deposition such as vapor deposition and sputtering, and then transferred to a substrate, are formed. A method of collectively forming by a printing method or the like can be considered. In these cases, the magnetic piece may be laminated with the concealing layer 75 and the protective layer 76 (see FIG. 9).

In any case, the magnetic material is formed on the substrate in parallel with a plurality of columns in a direction substantially perpendicular to the scanning direction, and
Multiple rows are formed in the scanning direction. At this time, the angle formed by the strip direction of the magnetic material and the scanning direction is set to -45 degrees or +45 degrees corresponding to the code to be recorded.
Further, when one bar corresponds to multi-valued or analog data, the correspondence between the angle in the range of −45 degrees to +45 degrees and the multi-valued or analog data is determined in advance,
It is necessary to set the angle between the strip direction of the magnetic material and the scanning direction.

[0028]

As described above, according to the present invention,
It is possible to provide a magnetic marker that can be read in a non-contact manner and can increase the amount of recordable information (claims 1 to 3). Further, the magnetic marker can be formed extremely easily and at low cost (claims 4 and 5).

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration of a magnetic recording medium according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a configuration for reading the magnetic recording medium.

FIG. 3 is a perspective view showing a configuration of an excitation coil and a detection coil in a configuration for reading the magnetic recording medium, and is a diagram showing a reading principle.

FIG. 4A and FIG. 4B are views showing a reading principle of the magnetic recording medium.

FIG. 5 is a diagram showing a reading principle in the magnetic recording medium.

FIG. 6 is a block diagram showing an electrical configuration for reading the magnetic recording medium.

FIG. 7 is a characteristic diagram showing an output signal in the same electrical configuration and a positional relationship between magnetic patterns.

FIG. 8A is a diagram showing the positional relationship of the magnetic piece to the scanning direction, and FIG. 8B is a characteristic showing the relationship between the output voltage and the angle formed by the magnetic piece with the scanning direction in the same electrical configuration. It is a figure.

FIG. 9 is a cross-sectional view showing the structure of a magnetic recording medium according to an example of the invention.

FIG. 10 is a plan view showing an example of the configuration of a conventional magnetic recording medium.

FIG. 11 is a cross-sectional view showing an example of the configuration of a conventional magnetic recording medium.

FIG. 12 is a characteristic diagram showing a detection signal by a magnetic pattern and a positional relationship of the magnetic pattern in a conventional magnetic recording medium.

[Explanation of symbols]

10 ... Magnetic recording medium, 11, 12 ... Magnetic pattern,
22 ... Detection coil, 23 ... Excitation coil

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location G11B 5/80 G06K 19/00 B (72) Inventor Masao Kuroiwa 1-5, Taito, Taito-ku, Tokyo No. 1 Toppan Printing Co., Ltd. (72) Inventor Ichiro Sasada 1-11-13 Atagohama, Nishi-ku, Fukuoka-shi, Fukuoka (72) Inventor Naoyuki Watanabe 19-22, Kotake, Fukuma-cho, Munakata-gun, Fukuoka Prefecture

Claims (6)

[Claims] 1. A magnetic marker comprising a magnetic pattern formed so that the direction of easy magnetization forms a predetermined angle with respect to the scanning direction, and the magnetic marker is encoded by the angle to record the magnetic pattern. A magnetic marker arranged in the scanning direction corresponding to a power code. 2. The magnetic marker according to claim 1, wherein the angle is −45 degrees or +45 degrees, each of which corresponds to a code “0” or “1”. 3. The magnetic marker according to claim 1, wherein the angle is in a range of −45 degrees to +45 degrees and corresponds to a value associated in advance in the range. 4. The magnetic marker according to claim 1, wherein a magnetic ink is printed on the substrate to form the magnetic pattern. 5. A foil made of a magnetic material is formed by deposition,
The magnetic marker according to claim 1, wherein the magnetic marker is transferred to a substrate to form the magnetic pattern. 6. A magnetic pattern formed so that the direction of easy magnetization forms a predetermined angle with the scanning direction, and magnetically excites the magnetic pattern arranged in the scanning direction corresponding to the code to be recorded. A step of generating an induced electromotive force by a component of the magnetically excited magnetic flux that is bent by the magnetic pattern and is in the same direction as or a direction opposite to the scanning direction; And a step of obtaining a code corresponding to the arrangement of the time pattern, the method for reading a magnetic marker.