JP3828604B2 - Apparatus and method for checking authenticity of detected object - Google Patents

Description

[0001]
[Industrial application fields]
This invention can be used for counterfeiting such as important documents, securities, money vouchers such as banknotes and checks, traveler's checks, ID cards, CD cards, credit cards, etc., passports, arts, public competition ballots, etc. The present invention relates to an apparatus and a check method for checking an object to be detected that needs to be prevented.
[0002]
[Prior art]
As a means for checking the authenticity of documents and the like, an apparatus that magnetically scans a scanning region has been proposed as disclosed in Japanese Utility Model Laid-Open No. 5-4307. In this type of apparatus, a magnetoresistive element (MR element) is provided in the detection unit, and the magnetic element provided on the object to be detected is detected by the magnetoresistive element. Therefore, in this apparatus, a detection signal having a unique waveform corresponding to the magnetic element can be obtained.
[0003]
The detection unit using the MR element arranges at least a pair of MR elements in the scanning direction and applies an external magnetic field generated by a magnet to the MR element. Then, the scanning region is moved with respect to the MR element, and the magnetic flux change generated when the magnetic element in the scanning region passes near the MR element is electrically captured by the MR element.
[0004]
[Problems to be solved by the invention]
When the object to be detected is magnetically scanned using the apparatus using the MR element as described above, the reproducibility of the detection signal is important. The reproducibility here means whether or not the same detection signal can be obtained at any time when the same object is repeatedly detected many times. That is, if the reproducibility is poor, a genuine object to be detected may be judged as a fake, and reliability is lowered.
[0005]
Theoretically, as long as the same scanning area is detected by the same detection unit, the same detection signal should be obtained, but even if the same detection unit is actually used, the position of the object to be detected with respect to the detection unit May deviate in a direction perpendicular to the scanning direction, and therefore the same detection signal is not always obtained. In particular, if the detection unit used when creating and issuing a detection object (when writing data) is different from the detection unit used when checking the detection object (when checking), manufacture of the detection part Since the position of the detection unit may vary from device to device due to the above assembly error or the like, it is difficult to obtain complete reproducibility.
[0006]
For example, in the case of a detection unit using an MR element having an element width of about 3 mm, if the positional deviation in the direction perpendicular to the scanning direction is within 0.3 mm, a level of reproducibility with no practical problem is obtained. . For this reason, in the conventional apparatus, it is necessary to manage the position of the detection unit with high accuracy so that the positional deviation of the detection unit does not exceed the allowable range, which causes the cost of the apparatus to be considerably increased. ing.
[0007]
Accordingly, an object of the present invention is to provide a check device and a check method for an object to be detected that can accurately reproduce a detection signal without aligning a detection unit with high accuracy.
[0008]
[Means for Solving the Problems]
The apparatus of the present invention developed to achieve the above object comprises a base material made of a non-magnetic material and a scanning region in which a large number of magnetic elements made of a magnetic material are randomly mixed. An apparatus for checking the authenticity of an object to be detected, having a detection unit for magnetically detecting the magnetic element, wherein the detection unit has a direction intersecting a scanning direction of the scanning region. A pair of facing MR elements are arranged in a scanning direction, and a first detection element pair that scans the scanning region, and a width of 7% to 20% of the element width of the MR element in a direction parallel to the first detection element pair . It has a pair of MR elements that are arranged with their positions shifted in the range, and a second detection element pair that scans the same scanning region as the first detection element pair.
[0009]
The magnetoelectric transducer used for sensing element pair magnetoresistive element (MR element) whose resistance value is substantially proportional to the strength of the magnetic field changes is that suitable. In the case of using the M R element, the amount of shifting the position of the second detection element pairs with respect to the first sensing element pair, or equal to 7-20% of the element width of the MR element.
[0010]
According to a third aspect of the present invention, in addition to the configuration of the first aspect, the apparatus of the present invention includes a transfer means for relatively moving an object to be detected in the scanning direction, and a magnetic field generating means for applying a magnetic field to the detection element pair. A detection circuit for obtaining a detection signal by detecting a change in electrical output generated in the detection element pair when the magnetic element passes in the vicinity of each detection element pair, and the first detection when issuing an object to be detected. When the detection signal obtained by the element pair is taken into the detection circuit and the object to be detected is collated, the detection signal obtained by the first detection element pair and the second detection element pair is taken into the detection circuit. Means, code writing means for recording data related to the detection signal obtained by the first detection element pair on the code display section, reading means for reading the data recorded on the code display section, and the reading means Thus, the read data of the code display unit is collated with the detection signals of all the detection element pairs (first detection element pair and second detection element pair), and any one of these detection signals is displayed in the code display. Means for judging that the detected object is authentic when it corresponds to the data of the section.
[0011]
In the check method of the present invention, as described in claim 4 , when the detection object is created and issued (when data is written to the code display unit), the scanning region is set using the first detection element pair. When a detection signal is obtained by scanning and the object to be detected is collated (when checking), the detection signal obtained by scanning the scanning area using all the detection element pairs is used as data in the code display section. To match.
[0012]
[Action]
In the present invention, a large number of magnetic elements are randomly mixed in the scanning region of the detection object in the preparation process for forming the detection object. The magnetic element is a wire, foil, powder, or high A magnetic polymer element in which magnetic powder is contained in a molecular material. A detection signal having a unique waveform obtained when the detection unit scans a scanning region in which such a magnetic element is mixed is used for checking the authenticity of an object to be detected.
[0013]
That is, in the apparatus according to the present invention, when the scanning region is moved with respect to the detection unit, the magnetic flux passing through each MR element changes according to the distribution of the magnetic elements, etc., so the characteristics of each MR element change with time. As a result, an output change occurs between the MR elements, and the change is extracted 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 elements, the size or arrangement direction of the magnetic elements, each scanning area has a unique output pattern.
[0014]
When the second detection element pair is provided on both sides of the first detection element pair, the scanning region is scanned using the first detection element pair in the creation process. This detection signal is encrypted according to a specific rule when the detected object is created and issued, and is recorded on a code display unit such as the detected object or a host computer.
[0015]
In the process of collating whether or not the object to be detected is authentic, a detection signal is obtained by scanning the scanning region using all detection element pairs. When only the first detection element pair and one second detection element pair are used, in the above creation process, two types obtained from the first detection element pair and the second detection element pair are used. The detected waveform is made into one waveform by an interpolation method or the like and recorded in the code display unit.
[0016]
As described above, at the time of creation / issuance of an object to be detected, one type of detection signal is obtained using the first detection element pair and registered in the code display unit. Since the detection object is collated by determining whether any of the detection signals is within the permissible level with respect to the data of the code display part, the positional deviation of the detection part at the time of collation is allowed. The range is enlarged, and the reproducibility of the detection signal is high without aligning the detection unit with high accuracy.
[0017]
【Example】
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 4, a large number of magnetic elements 12 are randomly mixed in the base material 11 of the detection object 10 so as to face an unspecified number of directions. The substrate 11 is made of a nonmagnetic material such as paper or plastic.
[0018]
For the magnetic element 12, for example, a high magnetic permeability material such as permalloy, sendust, soft ferrite, Co-based amorphous, or Fe—Ni-based alloy is suitable. The cross-sectional shape of the magnetic element 12 is not limited to a circle, and may be, for example, a polygon, a rectangle, an oval, or the like. The magnetic element 12 in the illustrated example has a wire shape, but may be a foil or powder. Moreover, a wire, foil, and powder may be mixed. Further, a fibrous or belt-shaped magnetic polymer element in which a large number of magnetic powders are mixed in a polymer material such as an acrylic resin may be used.
[0019]
The diameter (in the case of wire or fiber) or width (in the case of foil or strip) of the magnetic element 12 is, for example, about 5 to 100 μm, depending on the size of the object 10 to be detected, and the length is, for example, 1 to 30 mm. Degree. These magnetic elements 12 are randomly mixed so as to be included in the specific scanning region 17 at a certain density when the object to be detected 10 is manufactured.
[0020]
A code display unit 18 is provided on the detected object 10. In the code display unit 18, unique information corresponding to the distribution state of the magnetic elements 12 in the scanning region 17 is encrypted and written by the processing device 20 illustrated in FIG. 5.
[0021]
The processing device 20 includes a housing 25 and a transfer mechanism 26. The transfer mechanism 26 is configured to move the detected object 10 in the direction of arrow F in the drawing at a predetermined speed by a transfer member 27 using a belt, a roller, or the like.
[0022]
A magnetic sensor 30 that functions as a detection unit is provided in the middle of the movement path of the detected object 10. As shown in FIG. 1, the magnetic sensor 30 includes a first detection element pair 31 that is substantially located on the center line C in the width direction of the sensor 30. The detection element pair 31 includes a pair of MR elements 40 and 41 as an example of a magnetoelectric conversion element. Each of the MR elements 40 and 41 has an elongated shape having a longitudinal center line L so that the center line L intersects the scanning direction F (in FIG. 1, the angle θ is in a range of 90 ° ± 45 °). In addition, the elements 40 and 41 are arranged in parallel to each other. The shape of the MR elements 40 and 41 is not limited to a straight shape as shown in FIG. For example, the element 40, 41 may have a bent shape, an arc shape, or a corrugated shape in the middle portion in the longitudinal direction.
[0023]
The sensor 30 includes two sets of second detection element pairs 32 and 33. The configuration of the second detection element pair 32 and 33 is substantially the same as that of the first detection element pair 31. That is, one second detection element pair 32 has a pair of MR elements 40 and 41 arranged substantially perpendicular to the scanning direction F, and these elements 40 and 41 are the first detection element pair. The elements are arranged at a position shifted by a distance A in a direction parallel to the 31 elements 40 and 41. The other second detection element pair 33 also has a pair of MR elements 40 and 41 arranged substantially perpendicular to the scanning direction F, and these elements 40 and 41 are opposite to the detection element pair 32. The position is shifted by a distance B on the side. The lengths W of the MR elements 40 and 41 are common to each other, and an example of W is 3 mm.
[0024]
The apparatus 20 includes a first detection element pair 31 located on the center line C in the width direction of the sensor 30 and two sets of second elements arranged with their positions shifted in a direction parallel to the first detection element pair 31. Therefore, as shown in FIG. 3, the reproducibility exceeding the allowable level can be obtained by the amount corresponding to the amounts A and B in which the position of the second detection element pair is shifted, as shown in FIG. The range (positional deviation allowable range C, D) can be expanded. For example, when an MR element having a length of 3 mm is used, the positional deviation allowable ranges C ′ and D ′ are about ± 0.3 mm with only the first detection element pair 31. When the second detection element pair 32, 33 is shifted from the detection element pair 31 by about 20% (0.6 mm) of the element length W in the A and B directions, the reproducibility is more than the allowable level. The obtained ranges C and D could be expanded to ± 0.9 mm.
[0025]
The amounts A and B for shifting the positions of the second detection element pairs 32 and 33 relative to the first detection element pair 31 are suitably in the range of 7% to 20% of the length W of the elements 40 and 41. If the amounts A and B for shifting the position are 7% or less of the element length W, the amount capable of expanding the allowable range is insufficient. On the other hand, if it exceeds 20%, reproducibility exceeding the allowable level may not be obtained depending on the position displacement of the sensor 30. The allowable range may be further expanded by providing three or more second detection element pairs.
[0026]
The MR elements 40 and 41 are magnetoresistive elements whose electric resistance values change according to the strength of the magnetic field, and have positive magnetic characteristics using a compound semiconductor such as indium antimony or gallium arsenide according to required specifications. And those having negative magnetic properties such as nickel cobalt and ferromagnetic materials such as permalloy are used.
[0027]
A magnet 43 as an example of a magnetic field generating means is disposed behind the detection element pairs 31, 32, and 33. The magnet 43 may be a permanent magnet or an electromagnet using an electromagnetic coil.
[0028]
As representatively shown in FIG. 5 as a set of MR elements 40, 41, the MR elements 40, 41 are electrically connected to each other, and each MR element 40, 41 has the same strength by the magnet 43. A magnetic field is applied. One MR element 40 is connected to the controller 50 described below via a detection circuit 44. The other MR element 41 is connected to a DC power supply circuit 45. The scanning region 17 is moved in the direction in which the MR elements 40 and 41 are arranged (arrow F direction). The circuit configuration of the MR elements 40 and 41 is common to the detection element pairs 31, 32, and 33.
[0029]
As conceptually shown in FIG. 2, when the magnetic element 12 passes in the vicinity of the MR elements 40 and 41, the output voltage _Vout changes as the position of the magnetic element 12 changes to a, b, and c. Change. That is, the magnetic field of the magnet 43 to each MR element 40, 41 when the magnetic element 12 in the vicinity of the absence of the MR element 40, 41 is applied to the uniform, the resistance value of the MR element 40, 41 are equal to each other, the input voltage V _in In contrast, the output voltage V _out is about half (V _in / 2). When the magnetic element 12 passes in the vicinity of the MR elements 40 and 41 by moving the magnetic element 12 in the direction of the arrow F, the magnetic flux passing through the MR elements 40 and 41 changes with time according to the position of the magnetic element 12. At the same time, there is a difference in the resistance values of the MR elements 40 and 41, so that the output voltage _Vout almost fluctuates (V _in / 2).
[0030]
Here, assuming that the resistance of one MR element 40 is R ₁ and the resistance of the other MR element 41 is R ₂ , the output voltage V _out is expressed as V _out = V _in × {R ₁ / (R ₁ + R ₂ )}. It is. Since the output voltage V _out changes in magnitude according to the distribution density of the magnetic element 12 and the distribution state such as the diameter (or width), length, and direction of the magnetic element 12, the output voltage pattern of a specific waveform Is detected.
[0031]
Further, the processing device 20 includes a controller 50 using a microcomputer or the like that functions as a processing means for processing the detection signal, and a code writing for recording the following encryption code on the code display unit 18 of the detected object 10. And a code reading unit 52 for reading the encryption code recorded in the code display unit 18. The code writing unit 51 and the reading unit 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 device 65 is connected to the controller 50.
[0032]
The controller 50 takes the detection signal of the first detection element pair 31 into the controller 50 when the detection object 10 is created / issued, and the first detection element pair 31 and the detection object 10 when collating the detection object 10. A switching circuit 66 that functions as switching means for taking in the detection signals of the second detection element pairs 32 and 33 into the controller 50 is provided.
[0033]
Next, the operation of the embodiment device 20 will be described.
FIG. 6 shows an outline of a process for creating the detected object 10. In step S <b> 1, the magnetic element 12 is mixed into the base material 11 when the base material 11 of the detection object 10 is manufactured. When the magnetic element 12 is a powder, a random powder density (change in density) is applied to the scanning region 17, a random pattern is drawn with a constant powder density, or both are combined. Keep it together.
[0034]
The scanning / detecting step S2 includes a scanning step S3 and a detecting step S4. When the detected object 10 is moved in the direction of arrow F by the transfer mechanism 26 at a predetermined speed, a detection signal corresponding to the scanning region 17 is obtained. It is done.
[0035]
That is, in scanning step S3, when the object to be detected 10 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 sequentially pass in the vicinity of the MR elements 40 and 41. At this time, the magnetic flux passing through each of the MR elements 40 and 41 changes with time in accordance with the distribution state of the magnetic element 12, etc., so that the difference between the resistance values R ₁ and R ₂ of the MR elements 40 and 41 appears. The output voltage _Vout is measured as a unique output voltage pattern.
[0036]
The detection signal is detected by dividing the scanning region 17 every minute time, and the output voltage for each minute time is ranked in a plurality of stages and digitized. Thus, a coded detection signal specific to the scanning region 17 is obtained. In this creation process, the detection signal of the first detection element pair 31 is taken into the controller 50. When only one set of the second detection element pair 32 is used on one side of the first detection element pair 31, the first detection element pair 31 and the second detection element pair 32 are used in the creation process. One detection waveform is created by interpolation or the like from the two types of detection waveforms obtained.
[0037]
In the encryption step S5, the above-described detection signal is encrypted by the encryption code converter 62 according to a specific rule. The code thus encrypted is recorded on the code display unit 18 by the magnetic head of the code writing unit 51 in the writing step S6. Although the code display unit 18 of this embodiment is a magnetic band, the encryption code may be recorded as a bar code on the code display unit 18 using, for example, a print head. The encryption code may be stored in the code storage area of the host computer.
[0038]
The processing device 20 is also used to check whether the detected object 10 is authentic. FIG. 7 shows an outline of a verification process for checking the authenticity of the detected object 10. Step S11 includes a scanning step S3 and a detection step S4 that are the same as the process of creating the detection object 10 described above. By scanning the scanning region 17 at a predetermined speed by the sensor 30, the distribution of the magnetic elements 12 and the like are obtained. A corresponding detection signal is obtained. In this case, the switching circuit 66 operates so that the detection signals of the first detection element pair 31 and the second detection element pair 32 and 33 are taken into the controller 50.
[0039]
In the code reading step S <b> 12, the encryption code recorded on the code display unit 18 is read by the code reading unit 52. The encryption code is decrypted based on a predetermined rule by the encryption code converter 62 in the code reproduction step S13, whereby the verification code is reproduced. In the discrimination step S14, the three types of detection signals are compared with the verification code by the comparator 61. When at least one of the detection signals (plurality) is within an allowable level with respect to the verification code, it is determined that the detected object 10 is genuine, and the verification result is displayed on the display 65. The
[0040]
According to the processing device 20, as compared with the case where only the first detection element pair 31 is used alone, the positional deviation allowable range of the sensor 30 is expanded by the amount of the second detection element pair 32 and 33 provided at the time of collation. can do. For this reason, it is not necessary to align the sensor 30 with high accuracy, and the manufacturing of the processing apparatus 20 is facilitated. When only the first detection element pair 31 and one second detection element pair 32 are used, the two types of detection signals detected by the detection element pairs 31 and 32 are determined in the determination step S14. When any of these detection signals is within an allowable level with respect to the verification code, it is determined that the detected object 10 is genuine.
[0041]
In the process of creating the detected object 10 described above, when the encryption code is registered in the code storage area of the host computer, the encryption code may be called from the host computer in the verification process and verified with the detection signal. . Alternatively, in the verification process, the detection signal obtained in the detection step S4 may be encrypted according to the same rule as in the creation process, and this encryption code may be verified with the encryption code read in the code reading step S12.
[0042]
Further, like the detection unit (sensor) 30 shown in FIG. 8, the elements 40 and 41 of the plural pairs of detection elements 31, 32, and 33 may be arranged so as to enter each other. In this way, even a plurality of detection element pairs can be configured in a compact manner, and the cost can be reduced.
[0043]
【The invention's effect】
According to the present invention, the allowable positional deviation range of the detection unit at the time of collation is expanded as compared with the conventional device, and the reproducibility of the detection signal is high even if the detection unit is not aligned with high accuracy. For this reason, even when the detection unit used at the time of creation / issuance of the detected object is different from the detection unit used at the time of verification, it is possible to check whether the detected object is authentic or not with high reliability. it can. And since it is not necessary to make the position of a detection part highly accurate compared with the past, the cost of an apparatus can be reduced.
[Brief description of the drawings]
FIG. 1 is a plan view of a detection unit of a processing apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic diagram showing the operation of a part of the detection unit shown in FIG. 1;
FIG. 3 is a diagram showing a misalignment allowable range and data reproducibility of the detection unit shown in FIG. 1;
FIG. 4 is a plan view conceptually showing an example of an object to be detected.
FIG. 5 is a side view showing a schematic cross-sectional view of a processing apparatus including the detection unit shown in FIG. 1;
FIG. 6 is a flowchart showing processing steps when creating an object to be detected.
FIG. 7 is a flowchart showing processing steps when collating a detection object.
FIG. 8 is a plan view showing a modification of the detection unit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Detected object 11 ... Base material 12 ... Magnetic element 17 ... Scanning region 18 ... Code display part 20 ... Processing apparatus 30 ... Magnetic sensor (detection part)
31 ... 1st detection element pair 32, 33 ... 2nd detection element pair 40, 41 ... Magnetoelectric conversion element (MR element)
43 ... Magnetic field generating means (magnet)
50 ... Controller 51 ... Code writing unit 52 ... Code reading unit.
66 ... switching circuit (switching means)

Claims (4)

An apparatus for checking the authenticity of a detection object having a base material made of a non-magnetic material and a scanning region in which a large number of magnetic elements made of a magnetic material are mixed randomly,
A detection unit for magnetically detecting the magnetic element;
The detection unit includes a first detection element pair that scans the scanning region by arranging a pair of MR elements facing the direction intersecting the scanning direction of the scanning region in the scanning direction, and the first detection element pair. A pair of MR elements arranged in a range of 7% to 20% of the element width of the MR element in a direction parallel to each other and scanning the same scanning region as the first detection element pair . A pair of detector elements,
An apparatus for checking the authenticity of an object to be detected. Two pairs of the above-mentioned second detection element pairs are used, and these second detection element pairs are arranged at the same distance on the opposite sides in the direction parallel to the first detection element pair. An apparatus for checking the authenticity of an object to be detected according to claim 1 . An apparatus for checking the authenticity of a detection object having a base material made of a non-magnetic material and a scanning region in which a large number of magnetic elements made of a magnetic material are mixed randomly,
Magnetic detection means comprising a detection unit for magnetically detecting the magnetic element;
Transporting means for moving the object to be detected relative to the detection unit in the scanning direction of the scanning region;
The magnetic detection means includes
A first detection element pair that scans the scanning region by arranging a pair of MR elements facing the direction intersecting the scanning direction of the detection unit in the scanning direction;
A pair of MR elements arranged in a direction parallel to the first detection element pair and shifted in a range of 7% to 20% of the element width of the MR element; A second detection element pair that scans the same scanning area as
Magnetic field generating means for applying a magnetic field to each of the detection element pairs;
A detection circuit that detects a change in electrical output generated in the detection element pair when the magnetic element passes in the vicinity of each detection element pair and obtains a detection signal;
When the detection signal obtained by the first detection element is issued to the detection circuit when the detection object is issued and the detection object is collated, the first detection element pair and the second detection element pair Switching means for taking in the detection signal obtained by the above-mentioned detection circuit;
Code writing means for recording data related to the detection signal obtained by the first detection element pair on the code display unit;
Reading means for reading the data recorded in the code display unit;
The code display section data read by the reading means is collated with detection signals obtained by all the detection element pairs, and when one of the detection signals corresponds to the code display section data, Means for determining that the detected object is authentic;
An apparatus for checking the authenticity of an object to be detected. A method of checking the authenticity of a detection object having a base material made of a non-magnetic material and a scanning region in which a large number of magnetic elements made of a magnetic material are randomly mixed,
Including a creation process for creating the detected object, and a matching process for checking the detected object,
In the processing apparatus used for the creation process and the collation process, a pair of MR elements are arranged in a scanning direction, a first detection element pair for scanning the scanning region, and a direction parallel to the first detection element pair. A second detection element pair having a pair of MR elements arranged in a position shifted from 7% to 20% of the element width of the MR element and scanning the same scanning region as the first detection element pair; Provided,
The creation process includes a scanning step of applying a magnetic field to the first detection element pair while relatively moving the scanning region with respect to each detection element pair, and the magnetic element in the vicinity of the first detection element pair. A detection step of obtaining a detection signal by capturing a change in electrical output generated in the first detection element pair when passing, and a step of recording data related to the detection signal in a code display unit,
The collating process includes a scanning step of applying a magnetic field to the first detection element pair and the second detection element pair while moving the scanning region relative to the detection element pair, and the magnetic element is A detection step of obtaining a detection signal by detecting a change in electrical output generated in all of the detection element pairs when passing through the vicinity of one detection element pair and a second detection element pair; and the first detection detected by the detection step The detection signals of the detection element pair and the second detection element pair are collated with the data recorded on the code display unit, and any one of the plurality of detection signals is converted into the data recorded on the code display unit. A method for checking the authenticity of an object to be detected, comprising the step of determining that the object to be detected is authentic when it is within an allowable level.

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