JP2680980B2 - Method and apparatus for checking authenticity of an object to be detected - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to important documents, securities, bills such as banknotes and checks, traveler's checks, cards such as ID cards, CD cards, credit cards, passports, and works of art. The present invention relates to a method and an apparatus for checking an object to be detected which need to prevent forgery.

[0002]

2. Description of the Related Art As a means for checking the authenticity of documents and the like, Patent Application Publication No. 63-501250 (USP 4,820,
No. 912), a check method and apparatus using microwaves are known. In this prior art, a microwave is incident on a large number of metal wires randomly distributed in a document, and a unique digital mark corresponding to a response microwave flux is recorded at an appropriate position on the document according to a certain rule.
When the authenticity of the document is determined, a microwave is incident on the document, and the response microwave flux is compared with the digital mark. When the two match, it is determined that the document is authentic.

[0003]

The checking means using a microwave as in the prior art described above is susceptible to external noise when measuring a response microwave packet, so that the SN ratio deteriorates. Further, since the above-mentioned prior art device oscillates microwaves, it can be considered as a noise source. In addition, microwave transmitters and receivers are generally large and costly.

Further, if a metal wire is mixed into a thin object such as a bill, the metal wire may be exposed on the surface. When the metal wire is exposed, it is not preferable because it is conspicuous in appearance. Moreover, it becomes an obstacle when printing or coloring the object to be detected, and rust may occur. Also, when the object to be detected is bent, the metal wire may be bent to project onto the surface of the object to be detected, or the code unique to this object is different from that at the time of creation of the object to be verified. It may be impossible. These problems can be alleviated by making the diameter of the metal wire smaller, but cannot be a fundamental solution. Further, making the metal wire thinner is not practical because it not only causes the SN ratio to deteriorate but also leads to an increase in cost.

Therefore, it is an object of the present invention to avoid the problems found when burying a metal wire, and not to be a source of noise, and to detect a detected object having a high SN ratio. And to provide a device.

[0006]

The device of the present invention, which has been developed to achieve the above object, has a base material made of a non-magnetic material and a large number of magnetic materials in which an element body made of a polymer material contains a magnetic metal. An apparatus for checking the authenticity of an object to be detected, which has a polymer element and a scanning area in which the magnetic polymer element is randomly mixed, the first and second magnetoelectric elements arranged in a direction for scanning the scanning area. A magnetic sensor including a conversion element, a magnetic field generating means for applying an external magnetic field to the magnetoelectric conversion element and a magnetic polymer element in the scanning region, and a transfer means for relatively moving the object to be detected in the scanning direction with respect to the magnetoelectric conversion element. And, when the magnetic polymer element passes near the magnetoelectric conversion element, the change in the electrical output generated between the pair of magnetoelectric conversion elements in accordance with the magnetic polymer element is detected. A detection circuit for obtaining a detection signal peculiar to the inspection area, a means for obtaining an encryption code by encrypting the detection signal, a code writing means for recording the encryption code in the code display section, and a recording in the code display section. The reading means for reading the above-mentioned encryption code and the encryption code read by the reading means are collated with the detection signal detected by the magnetic sensor, and when the two correspond to each other, the detected object is authentic. And a means for judging.

As the magnetoelectric conversion element, a magnetoresistive element (MR element) whose resistance value increases substantially in proportion to the strength of the magnetic field is suitable. For example, a magnetic diode or a Hall element other than the MR element may be used as long as the characteristic changes.

The magnetic metal contained in the magnetic polymer element is, for example, permalloy, sendust, C or the like.
Powder made of magnetically soft high-permeability magnetic material such as o-type amorphous or soft ferrite, or powder made of magnetically hard high coercive force material such as ferrite, Sm-Co alloy, and Nd alloy The body is suitable.

[0009]

According to the present invention, a large number of magnetic polymer elements are randomly mixed in the scanning area of the object to be detected in the production process for producing the object to be detected, and this scanning area is obtained by scanning with the magnetic sensor. The unique detection signal is used to check the authenticity of the detected object. That is, when the scanning region is moved with respect to the pair of magnetoelectric conversion elements, the first and second magnetic polymer elements are distributed in accordance with the distribution of the magnetic polymer elements.
Since the magnetic flux passing through the magnetoelectric conversion element changes, the characteristics of each magnetoelectric conversion element change with time. As a result, an output change occurs between the magnetoelectric conversion elements and is taken out as a detection signal. Since this detection signal changes for each minute portion of the scanning area depending on the mixing density of the magnetic polymer element, the size or the arrangement direction of the magnetic polymer element, the detection signal has an output pattern unique to each scanning area. This detection signal is encrypted according to a specific rule when the detected object is created and recorded on the code display unit such as the detected object or the host computer.

In the process of checking whether the detected object is genuine or not, the scanning area is scanned in the same manner as the above-described preparation process to obtain a detection signal unique to the scanning area, and When the signal corresponds to the encryption code recorded on the code display section, it is determined that the detected object is genuine.

The magnetic polymer element mixed into the object of the present invention is sufficiently flexible as compared with a metal wire.
Even if the element is bent when mixed with a thin object to be detected, there is no problem that the element projects or breaks on the surface of the object to be detected. For this reason, this detection object can maintain a favorable surface state, does not rust, and can be printed or colored without any problem. Further, a change in the distribution pattern of the elements is also avoided.

[0012]

Embodiments of the present invention will be described below with reference to FIGS. As shown in FIG. 2, a large number of magnetic polymer elements 12 are randomly mixed in the base material 11 of the object to be detected 10 so as to face an unspecified large number of directions. The base material 11 is made of a non-magnetic material such as paper or plastic.

The magnetic polymer element 12 is a wire-shaped element in which a magnetic metal powder 14 is mixed in the inside of an element body 13 made of a polymer material, for example, as shown in the cross section shown in FIG. An example of the polymer material used for the element body 13 is polyethylene, polyester, urethane, or the like, in short, a well-known synthetic resin having appropriate flexibility can be applied. As the magnetic metal powder 14, a magnetically soft high permeability magnetic material or a magnetically hard high coercive force material is suitable.

As an example of a method for manufacturing the magnetic polymer element 12, a dry manufacturing method using a double-structured container 15 as shown in FIG. 4 is applied. In this case, the polymeric material 13a that has been liquefied by heating to, for example, 200 ° C. to 500 ° C. is placed in the outer chamber 15a of the container 15, and the magnetic metal powder 14 mixed with the liquid polymeric material is placed in the inner chamber 15b of the container 15. Put in. Then, both the polymer material 13a and the magnetic metal powder 14 mixed with the polymer material are supplied to the nozzle 16 at the bottom of the container 15.
The polymer material 13a comes out of the nozzle 16 and is cooled by dropping from the nozzle or extruding with pressure.
During solidification, the magnetic metal powder 14 is mixed inside the polymer material 13a.

Alternatively, as shown in FIG. 5, by preliminarily impregnating a pipe 13b made of a polymer material with an alkaline solution 14a containing magnetic metal ions, magnetic metal is deposited on the inner surface 13c of the pipe 13b. Such a wet manufacturing method may be applied.

These magnetic polymer elements 12 are mixed so as to be contained in a specific scanning area 17 at a certain density when the object 10 to be detected is manufactured. In addition, a nonwoven fabric is prepared by the magnetic polymer element 12, and the nonwoven fabric is cut into an appropriate size and the scanning region 1 of the detection object 10 is cut.
7 may be embedded.

Although the magnetic polymer element 12 in the illustrated example has a wire shape, the cross-sectional shape is not limited to a circular shape, and may be, for example, a polygonal shape, a rectangular shape, an oval shape or the like. The element 12 may be ribbons or foils, or a mixture thereof.
The outer diameter D1 (or thickness) of the magnetic polymer element 12 depends on the size of the object to be detected 10, but is, for example, about 5 to 50 μm. The inner diameter D2 of the element body 13 is 2 to 20 μm.
m. The particle size of the magnetic metal powder 14 is, for example, 1 μm or less. The mixing ratio of the magnetic metal powder 14 is 40 by volume.
Approximately 70% is suitable, and it is desirable that the magnetic metal powder 14 be mixed in the center of the cross section of the element 12 as much as possible.

A code display section 18 is provided on the detected object 10. Unique information corresponding to the distribution state of the magnetic polymer elements 12 in the scanning region 17 is encrypted and written in the code display unit 18 by the processing device 20 illustrated in FIG. 1. The processing device 20 includes a housing 25 and a transfer mechanism 26. The transfer mechanism 26 uses the transfer member 27 that uses a belt, a roller, or the like to detect the object 1 to be detected.
0 is moved at a predetermined speed in the direction of arrow F in the figure.

A magnetic sensor 30 is provided midway along the movement path of the object to be detected 10. The magnetic sensor 30 arranges a first MR element 31 and a second MR element 32 as an example of a pair of magneto-electric conversion elements in the moving direction of the detection object 10 and has the MR elements 31 and 32 behind them. A magnet 33 is disposed as an example of a magnetic field generating means. The magnet 33 may be a permanent magnet as shown in FIG. 6, or an electromagnet using a coil 33a as shown in FIG. 7 may be used.

The MR elements 31 and 32 are magnetoresistive elements whose electric resistance value changes according to the strength of the magnetic field. Depending on required specifications, for example, a positive magnetic field using a compound semiconductor such as indium antimony or gallium arsenide is used. A material having characteristics or a material having negative magnetic characteristics such as a ferromagnetic material such as nickel cobalt or permalloy is used.

These MR elements 31 and 32 are electrically connected to each other, and moreover, the MR elements 31 and 32 are connected to each other.
A magnetic field of the same strength is applied by the magnet 33. Further, the first MR element 31 is connected to a controller 50 described below via a detection circuit 44. Second M
The R element 32 is connected to the DC power supply circuit 45. The scanning area 17 is moved along the direction in which the MR elements 31 and 32 are arranged.

As conceptually shown in FIG. 6, the MR element 3
When the magnetic polymer element 12 passes under 1, 32, as the position of the magnetic polymer element 12 changes to a, b, c, the output voltage V _out changes as shown in FIG.
That is, when the magnetic polymer element 12 is not present in the vicinity of the MR elements 31 and 32, the magnetic field of the magnet 33 is evenly applied to the MR elements 31 and 32, and the MR elements 31 and 32 are
, The output voltage V _out is about half (V _in / 2) with respect to the input voltage V _in . Then, when the magnetic polymer element 12 passes under the MR elements 31 and 32 by moving the magnetic polymer element 12 in the direction of the arrow F, each MR is moved in accordance with the position of the magnetic polymer element 12.
As the magnetic flux passing through the elements 31 and 32 changes with time, and the resistance values of the MR elements 31 and 32 differ, the output voltage V _out rises and falls substantially at (V _in / 2).

Here, the resistance of the first MR element 31 is set to R ₁ ,
Assuming that the resistance of the second MR element 32 is R ₂ , the output voltage V
_out is represented by V _out = V _in × {R ₂ / (R ₁ + R ₂ )}. The output voltage V _out changes in size according to the distribution density of the magnetic polymer element 12, the diameter (or thickness), the length, the direction of the magnetic polymer element 12, and the like. A unique output voltage pattern is detected as shown.

The processing device 20 includes a controller 50 using a microcomputer, a code writing section 51 for recording the following encryption code on the code display section 18 of the object to be detected 10, and a code display section 18 for recording. A code reading unit 52 for reading the generated encryption code is provided. The code writing section 51 and the reading section 52 are connected to a read / write circuit 53. The controller 50 includes an A / D converter 60, a comparator 61, an encryption code converter 62, and the like. A display 65 is connected to the controller 50.

Next, the operation of the apparatus 20 of the above embodiment will be described. FIG. 10 shows an outline of a process for producing the detected object 10. In step S1, the magnetic polymer element 12 is mixed into the substrate 11 when the substrate 11 of the detection object 10 is manufactured. The scanning / detecting step S2 includes a scanning step S3 and a detecting step S4,
The detection object 10 is moved at a predetermined speed in the direction of arrow F in FIG.
A unique detection signal corresponding to is obtained.

That is, in the scanning step S3, when the object 10 to be detected is moved in the direction of arrow F at a predetermined speed by the transfer mechanism 26, a plurality of minute portions of the scanning region 17 are MR-extracted.
The light sequentially passes near the elements 31 and 32. At this time, the density, diameter, direction, and length of the magnetic polymer element 12 and the magnetic metal powder 1
The magnetic flux passing through the MR elements 31 and 32 changes with time according to the property of No. 4, etc.
_Due to the difference between ₁ and R ₂ , the output voltage V _out is measured as an inherent output voltage pattern as illustrated in FIG. 9. In this embodiment, in the detection step S4,
The scanning area 17 is divided and detected for each minute time, and the output voltage for each minute time is ranked in a plurality of stages and digitized. In this way, a coded detection signal specific to the scanning area 17 is obtained.

In the encryption step S5, the above-mentioned detection signal is encrypted by the encryption code converter 62 according to a specific rule. The code encrypted in this way
In the writing step S6, the data is recorded on the code display unit 18 by the magnetic head of the code writing unit 51. The code display section 18 of this embodiment is a magnetic band.
May be recorded as a barcode. Further, the encryption code may be stored in a code storage area of a host computer.

The processing device 20 is also used to check whether or not the object 10 to be detected is authentic. FIG. 11 shows the outline of the matching process for checking the authenticity of the detected object 10. Step S11 includes a scanning step S3 and a detection step S4 similar to the above-described process of creating the detected object 10. The magnetic sensor 30 scans the scanning region 17 at a predetermined speed to distribute the magnetic polymer element 12. Etc. to obtain a detection signal.

In the code reading step S12,
The code reading unit 52 reads the encryption code recorded on the code display unit 18. This encryption code
In the code reproduction step S13, the code for decryption is reproduced by the encryption code converter 62 based on a predetermined rule. And the discriminating step S
In step 14, the verification code and the detection step S4
Is compared with the detection signal detected by the comparator 61. Only when the two match, the detected object 10 is determined to be genuine, and the result of the comparison is displayed on the display 65.

According to the processing device 20, the object 10 to be detected is
Since the scanning area 17 can be detected even when the external magnetic field applied to the image is weak, even if the encryption code or other information is magnetically recorded on the code display section 18 or other places, such magnetic information is There is no destruction. Since the magnetic sensor 30 obtains a detection signal based on the output ratio between the two MR elements 31 and 32, it is less susceptible to temperature changes and noise. Further, in a general magnetic head, the magnitude of the output changes depending on the moving speed of the detected object. However, the processing device 20 including the magnetic sensor 30 according to the present embodiment is not affected by the moving speed or temperature change. And the output always shows a substantially constant magnitude.

In addition, in the above-described process of creating the detected object 10, when the cryptographic code is registered in the code storage area of the host computer, the cryptographic code is called from the host computer in the collation process and collated with the detection signal. May be. Alternatively, in the collation process, the detection signal obtained in the detection step S4 may be encrypted according to the same rules as in the creation process, and this encryption code may be collated with the encryption code read in the code reading step S12.

The magnetic polymer element 12 used in the object to be detected 10 of the above embodiment is extremely flexible and has a high degree of flexibility so that it cannot be bent even when bent. For this reason, for example, when the detection object 10 is bent when it is mixed with the detection object 10 as thin as paper, the element 12 is bent and the detection object 10 is bent.
This does not cause a problem such as protruding from the surface of the object 10 and does not affect the unique pattern when the object 10 is created.

Moreover, since the surface of the magnetic polymer element 12 is covered with the element body 13 made of a polymer material, it can be easily colored by a well-known coloring means. Therefore, there is no problem in performing printing, coloring, or the like so that even if a part of the element 12 is exposed on the surface of the detection object 10, it is not noticeable. In particular, when the base material 11 of the object to be detected 10 is made of paper, it is not known from the outside that the element 12 is mixed, so that the security is high. When a high coercive force material (for example, a magnetically hard metal such as ferrite, Sm—Co alloy, or Nd alloy) is used for the magnetic metal powder 14 of the magnetic polymer element 12, the magnetic polymer element 12 is previously attached. Can be magnetized.

The present invention can also be proved that the painting is genuine by embedding the magnetic polymer element 12 on the back surface of the canvas of the painting and recording the encryption code in the code display portion. Further, the present invention is useful for discriminating imitation from a real object if the magnetic polymer element 12 is embedded in a three-dimensional object such as an art object.

[0035]

According to the present invention, since the object to be detected in which a large number of magnetic polymer elements are randomly mixed is magnetically checked based on the output of the magnetoelectric conversion element, it is possible to compare with the checking means using microwaves. The cost of the processing device is low, and the device can be made compact. Further, since it is possible to detect using a weak magnetic field, noise generation is avoided and S
The N ratio is also high. Even if the detected object is bent, the magnetic polymer element does not cause problems such as protruding or breaking on the surface of the detected object, and a good surface condition suitable for printing or coloring can be obtained, and the distribution of elements Problems such as pattern changes will also disappear. Further, generation of rust can be avoided.

[Brief description of the drawings]

FIG. 1 is a side view schematically showing a partial cross section of an apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view conceptually showing an example of an object to be detected.

FIG. 3 is a sectional view of a magnetic polymer device used in an embodiment of the present invention.

4 is a sectional view showing an outline of an apparatus for manufacturing the magnetic polymer element shown in FIG.

FIG. 5 is a sectional view showing another example of an apparatus for producing a magnetic polymer element.

6 is a schematic diagram of a magnetic sensor in the apparatus shown in FIG.

FIG. 7 is a schematic diagram showing a modification of the magnetic sensor.

8 is a diagram showing a change in basic output voltage of the magnetic sensor shown in FIG.

9 is a diagram showing an example of an output pattern of the device shown in FIG.

FIG. 10 is a flowchart showing steps of processing when creating an object to be detected.

FIG. 11 is a flowchart showing steps of a process for collating an object to be detected.

[Explanation of symbols]

10 ... Object to be detected, 11 ... Base material, 12 ... Magnetic polymer element, 17 ... Scan area, 18 ... Code display part, 20 ... Processing device, 26 ... Transfer mechanism, 30 ... Magnetic sensor, 31 ... First
Magnetic-electric conversion element, 32 ... Second magnetic-electric conversion element, 33 ... Magnetic field generating means, 44 ... Detection circuit, 50 ... Controller, 5
1 ... Code writing unit, 52 ... Code reading unit.

Claims (2)

(57) [Claims] 1. An object having a base material made of a non-magnetic material, a large number of magnetic polymer elements in which an element main body made of a polymeric material contains a magnetic metal, and a scanning region in which the magnetic polymer elements are randomly mixed. A method for checking the authenticity of a detected object, comprising: a creating process for creating the detected object; and a collation process for checking the detected object, wherein the creating process includes: A scanning step of applying an external magnetic field to the magnetic polymer element in the scanning area and the magnetic polymer element in the scanning area while relatively moving the scanning area with respect to a pair of magnetoelectric conversion elements arranged in the scanning direction; By detecting the change in the electrical output that occurs between the pair of magnetoelectric conversion elements according to the magnetic polymer element when passing near the element, the scanning area specific to this scanning area is detected. A detection step of obtaining a signal, a step of obtaining a cryptographic code by encrypting the detection signal, and a step of recording the cryptographic code in a code display section, and the collation process includes the pair of magnetoelectric conversion elements. A scanning step of applying an external magnetic field to the magneto-electric conversion element and the magnetic polymer element in the scanning area while moving the scanning area relative to the magnetic polymer element when the magnetic polymer element passes in the vicinity of the magneto-electric conversion element. Correspondingly, a detection step of obtaining a detection signal peculiar to this scanning area by capturing a change in the electrical output generated between the pair of magnetoelectric conversion elements, and the detection signal detected by the detection step and recorded on the code display section. Discriminating step of collating the encrypted code and judging that the detected object is authentic when both correspond How to Check the authenticity of the object to be detected, characterized in that it comprises a. 2. A substrate having a non-magnetic material, a large number of magnetic polymer elements in which an element main body made of a polymer material contains a magnetic metal, and a scanning region in which the magnetic polymer elements are randomly mixed. A device for checking the authenticity of an object to be detected, comprising: a magnetic sensor having first and second magnetoelectric conversion elements arranged in a scanning direction of the scanning area; a magnetic polymer element of the magnetoelectric conversion element and a scanning area; Magnetic field generating means for applying an external magnetic field to the magnetic field, transfer means for relatively moving the object to be detected in the scanning direction with respect to the magnetoelectric conversion element, and the magnetic polymer when the magnetic polymer element passes near the magnetoelectric conversion element. A detection circuit that captures a change in the electrical output generated between the pair of magnetoelectric conversion elements according to the element to obtain a detection signal specific to this scanning region, and encrypts the detection signal. Means for obtaining a cryptographic code by means of the above, a code writing means for recording the cryptographic code in the code display section, a reading means for reading the cryptographic code recorded in the code display section, and a read means for reading the code. The authenticity of the detected object is characterized by further comprising means for collating the code with the detection signal detected by the magnetic sensor and determining that the detected object is authentic when the two correspond to each other. Device for checking.