JPH08279016A - Device and method for checking genuineness of detected body - Google Patents

Abstract

PURPOSE: To improve the reproducibility of a detection signal even if the position precision of a detection part is inferior when the detected body is magnetically scanned by using an MR element, etc. CONSTITUTION: Many magnetic elements are mixed at random in the scanned area for the detected body. The detection part (magnetic sensor) 30 of a processor for checking the genuineness of the detected body is equipped with a 1st detecting element couple 31 and 2nd detecting element couples 32 and 33. Those detecting element couples 31, 32, and 33 are each equipped with a couple of MR elements 40 and 41 which are arrayed in the scanning direction. The MR elements 40 and 41 of the 2nd detecting element couples 32 and 33 are arranged shifting in position in the direction parallel to the elements 40 and 41 of the 1st detecting element couple 31. The processor makes a scan by the 1st detecting element couple 31 when generating and issuing the detected body and registers obtained data. When the detected body is collated, scans are made by using all the detecting element couples 31, 32, and 33 to obtain detection signals.

Description

Detailed Description of the Invention

[0001]

The present invention relates to important documents and securities, cash vouchers such as banknotes and checks, travelers checks, ID cards, CD cards, credit cards and other cards, passports, works of art, public voting tickets. As described above, the present invention relates to an apparatus and a check method for checking an object to be detected that needs to be prevented from forgery.

[0002]

2. Description of the Related Art As a means for checking the authenticity of a document or the like, a device for magnetically scanning a scanning region has been proposed, as disclosed in Japanese Utility Model Laid-Open No. 5-4307. In this type of device, a magnetoresistive element (MR element) is provided in the detection unit, and the magnetic element provided in 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.

A detection unit using an 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 area is moved with respect to the MR element so that the MR element electrically catches the change in magnetic flux generated when the magnetic element in the scanning area passes near the MR element.

[0004]

When the object to be detected is magnetically scanned by 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 substantially the same detection signal is always obtained when the same object to be detected is repeatedly detected many times. That is, if the reproducibility is poor, the genuine object to be detected may be determined to be a fake, and the reliability is lowered.

Theoretically, the same detection signal should be obtained as long as the same scanning region is detected by the same detection section. However, even if the same detection section is actually used, the detected section will be detected. Since the position of the object may deviate in the direction perpendicular to the scanning direction, the same detection signal is not always obtained. In particular, if the detection unit used when creating / issuing the detected object (when writing data) and the detection unit used when collating the detected object (when checking) are different, manufacture of the detection unit Since the position of the detection unit may vary from device to device due to the above-mentioned assembly error, it is difficult to obtain perfect reproducibility.

For example, in the case of a detector using an MR element with an element width of about 3 mm, if the positional deviation in the direction perpendicular to the scanning direction is within 0.3 mm, reproducibility at a level practically no problem is obtained. Has been. For this reason, in the conventional device, it is necessary to manage the position of the detection unit with high accuracy at the time of manufacturing so that the positional deviation of the detection unit does not exceed the above-mentioned allowable range, which causes a considerable increase in the cost of the device. ing.

Therefore, it is an object of the present invention to provide a checking device and a checking method for an object to be detected, which can accurately reproduce the detection signal without aligning the detecting portion with high accuracy.

[0008]

The apparatus of the present invention developed to achieve the above object has, as described in claim 1, a base material made of a non-magnetic material and a large number of magnetic elements made of a magnetic material. Is a device for checking the authenticity of an object to be detected having a scanning area randomly mixed therein, and having a detecting section for magnetically detecting the magnetic element, wherein the detecting section is the scanning area. A pair of magnetoelectric conversion elements facing a direction intersecting the scanning direction of the first detection element pair arranged in the scanning direction, and a first detection element pair arranged in a direction parallel to the first detection element pair and displaced from each other. And two detection element pairs.

A magnetoresistive element (MR element) whose resistance value changes substantially in proportion to the strength of the magnetic field is suitable for the magnetoelectric conversion element used for the above-mentioned detection element pair, but in short, it depends on the strength of the magnetic field. A magnetic diode or a Hall element, for example, may be used in addition to the MR element, as long as the electrical characteristics such as the resistance value change. When the MR element is used, as described in claim 3, the amount by which the position of the second detection element pair is displaced with respect to the first detection element pair is 7 to 20% of the element width of the MR element. It is good to

According to a fifth aspect of the present invention, in addition to the configuration of the first aspect of the invention, a transfer means for relatively moving the object to be detected in the scanning direction and a magnetic field for applying a magnetic field to the detection element pair. Generating means, a detection circuit for obtaining a detection signal by capturing 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 detection circuit for issuing an object to be detected. When the detection signal obtained by the first detection element pair is taken into the detection circuit and the object to be detected is collated, the detection signals obtained by the first detection element pair and the second detection element pair are detected by the detection circuit. Switching means to take in,
Code writing means for recording data relating to the detection signal obtained by the first detection element pair on the code display part;
Reading means for reading the data recorded in the code display portion, and data of the code display portion read by the reading means for all the detection element pairs (first detection element pair and second detection element pair). Means for checking the detected object is authentic when any of these detected signals corresponds to the data of the code display section.

In the checking method of the present invention, as described in claim 6, the first detection element pair is used when creating / issuing the object to be detected (when writing data to the code display portion). Scan the scanning area to obtain the detection signal,
When the object to be detected is collated (at the time of checking), the detection signal obtained by scanning the scanning region using all the detection element pairs is collated with the data of the code display section.

[0012]

According to the present invention, a large number of magnetic 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. The magnetic element is a wire, foil or powder made of a magnetic material. Alternatively, it is a magnetic polymer element in which magnetic powder is contained in a polymer material. A detection signal having a unique waveform obtained when the scanning section in which such a magnetic element is mixed is scanned by the detection unit is used for checking the authenticity of the detected object.

That is, in the device of the present invention, when the scanning region is moved with respect to the detection portion, the magnetic flux passing through each magnetoelectric conversion element changes according to the distribution of the magnetic elements, so that the characteristics of each magnetoelectric conversion element change with time. Change. As a result, a change in output occurs between the magnetoelectric conversion elements and the signal is extracted as a detection signal. This detection signal has an output pattern peculiar to each scanning area because it changes for each minute portion of the scanning area depending on the mixing density of magnetic elements, the size of magnetic elements, the arrangement direction, and the like.

When the second detection element pair is provided on each side of the first detection element pair, the scanning region is scanned using the first detection element pair in the above-described production process. And this detection signal creates an object to be detected.
When issued, it is encrypted according to a specific rule and recorded on the code display unit such as the object to be detected or the host computer.

In the process of verifying whether the object to be detected is authentic or not, the scanning area is scanned using all the detection element pairs to obtain a detection signal. When only the first detection element pair and the pair of second detection element pairs are used, the two types of two types obtained from the first detection element pair and the second detection element pair in the above manufacturing process are used. The detected waveform is converted into one waveform by an interpolation method or the like and recorded in the code display section.

As described above, when creating / issuing an object to be detected, the first detecting element pair is used to obtain one type of detection signal so as to be registered in the code display section, and at the time of collation, all detecting element pairs are registered. Since the detection object is collated by determining whether any of the plurality of detection signals according to the above is within an allowable level for the data of the code display portion, The positional deviation allowable range is expanded, and the reproducibility of the detection signal is high even if the detection unit is not aligned with high accuracy.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below 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 object to be detected 10 so as to face unspecified large numbers of directions. The base material 11 is made of a non-magnetic material such as paper or plastic.

The magnetic element 12 is, for example, permalloy, sendust, soft ferrite, Co type amorphous, Fe.
A high magnetic permeability material such as a Ni-based alloy is suitable. The cross-sectional shape of the magnetic element 12 is not limited to a circle, but may be, for example, a polygon or a rectangle,
It may be oval or any other shape. The magnetic element 12 of the illustrated example
Is a wire, but may be a foil or a powder. Moreover, the wire, the foil, and the powder may be mixed. Further, a fibrous or band-shaped magnetic polymer element in which a large number of magnetic powders are mixed in a polymer material such as acrylic resin may be used.

The diameter (in the case of a wire or a fiber) or width (in the case of a foil or a band) of the magnetic element 12 is, for example, about 5 to 100 μm, depending on the size of the object to be detected 10, and its length is, for example. It is about 1 to 30 mm. These magnetic elements 12 are randomly mixed so as to be included in a specific scanning region 17 at a certain density when the detected object 10 is manufactured.

A code display section 18 is provided on the detected object 10. Unique information corresponding to the distribution state of the magnetic 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.

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 at a predetermined speed in the direction of arrow F in the figure by a transfer member 27 using a belt, rollers, or the like.

A magnetic sensor 30 functioning as a detection section is provided in the middle of the moving path of the object to be detected 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. The MR elements 40 and 41 each have an elongated shape having a longitudinal centerline L, and the centerline L intersects the scanning direction F (angle θ in the range of 90 ° ± 45 ° in FIG. 1).
The elements 40 and 41 are arranged parallel to each other. The shapes of the MR elements 40 and 41 are not limited to the straight shapes as shown in FIG. For example, element 4
It may have a bent shape, a circular arc shape, or a corrugated shape in the longitudinal middle portion of 0, 41.

The sensor 30 also includes two pairs of second detection elements 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, the one second detection element pair 32 is
It has a pair of MR elements 40 and 41 arranged substantially at right angles to the scanning direction F, and these elements 40 and 41 are
The detection element pair 31 is arranged with a position shifted by a distance A in a direction parallel to the elements 40 and 41. The other second detection element pair 33 also has a pair of MR elements 40 and 41 arranged substantially at right angles to the scanning direction F, and these elements 40 and 41 are opposite to the detection element pair 32. The position is shifted to the side by a distance B. MR elements 40, 41
Have a common length W, and an example of W is 3 mm.

The device 20 is arranged such that the first detection element pair 31 located on the center line C in the width direction of the sensor 30 and the first detection element pair 31 are displaced from each other in the direction parallel to the first detection element pair 31.
Since the pair of second detection element pairs 32 and 33 is provided, as shown in FIG. 3, reproduction of a level equal to or higher than the allowable level by an amount corresponding to the amounts A and B in which the position of the second detection element pair is displaced. It is possible to expand the range (positional shift allowable range C, D) in which the property is obtained. For example, when using an MR element with a length of 3 mm,
With the first detection element pair 31 alone, the positional deviation allowable range C ′,
Although D'was about ± 0.3 mm, as in the present embodiment, the first detection element pair 31 and the second detection element pair 32,
33 is approximately 20% of the element length W in the A and B directions (0.6 m
m) In the case of arranging them in a staggered manner, the ranges C and D in which the reproducibility above the allowable level was obtained could be expanded to ± 0.9 mm.

The amounts A and B by which the positions of the second detection element pair 32 and 33 are displaced with respect to the first detection element pair 31 are determined by the element 4
A range of 7% to 20% of the length W of 0.41 is suitable. If the amounts A and B for shifting the positions are 7% or less of the element length W, the amount by which the allowable range can be expanded is insufficient. Also, 2
If it exceeds 0%, reproducibility exceeding an allowable level may not be obtained depending on the amount of displacement of the sensor 30. The allowable range may be further expanded by providing three or more second detection element pairs.

The MR elements 40 and 41 are magnetoresistive elements whose electric resistance value changes according to the strength of a magnetic field, and according to required specifications, 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.

Behind the detection element pairs 31, 32, 33, a magnet 43 as an example of magnetic field generating means is arranged. The magnet 43 may be a permanent magnet or an electromagnet using an electromagnetic coil.

As shown in FIG. 5 as a representative of a pair of MR elements 40 and 41, the MR elements 40 and 41 are electrically connected to each other, and the same magnet 43 is used for each MR element 40 and 41. A strong 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 the DC power supply circuit 45. The scanning region 17 is moved in the direction in which the MR elements 40 and 41 are arranged side by side (direction of arrow F). Such M
The circuit configuration of the R elements 40 and 41 is such that
It is common to 2 and 33.

As conceptually shown in FIG.
When the magnetic element 12 passes near 0 and 41, the magnetic element 12
Of the output voltage V as the position of V changes from a to b to c.
_out changes. That is, when the magnetic element 12 does not exist near the MR elements 40 and 41, the MR elements 40 and 4
The magnetic field of the magnet 43 is evenly applied to the
Since the resistance values of 0 and 41 are equal to each other, the output voltage V _out is about half (V _in / 2) with respect to the input voltage V _in . When the magnetic element 12 moves near the MR elements 40 and 41 due to the movement of the magnetic element 12 in the arrow F direction, the magnetic flux passing through the MR elements 40 and 41 changes with time according to the position of the magnetic element 12. And the MR elements 40 and 41
The output voltage V _{out is} almost equal to (V _in
/ 2) comes to go up and down.

Here, the resistance of _one MR element 40 is set to R ₁ ,
When the resistance of the other MR element 41 is R ₂ , the output voltage V
_out is represented by V _out = V _in × {R ₁ / (R ₁ + R ₂ )}. The output voltage V _out changes in size according to the distribution density of the magnetic elements 12 and the distribution state such as the diameter (or width), length, and direction of the magnetic elements 12, so that the output voltage pattern of a unique waveform is obtained. Is detected.

Further, the processing device 20 records the following encryption code on the controller 50 using a microcomputer or the like which functions as a processing means for processing the detection signal and the code display portion 18 of the detected object 10. The code writing unit 51, the code reading unit 52 for reading the encryption code recorded in the code display unit 18, and the like. 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.

The controller 50 takes in the detection signal of the first detection element pair 31 to the controller 50 when creating / issuing the object to be detected 10, and to collate the object 10 to be detected, the first detecting element. A pair 31 and a second detection element pair 32,
A switching circuit 6 functioning as a switching means for taking the detection signal of 33 into the controller 50.
6 is provided.

Next, the operation of the apparatus 20 of the embodiment will be described. FIG. 6 shows an outline of a process for producing the detected object 10. In step S1, the magnetic element 12 is mixed into the base material 11 when the base material 11 of the object to be detected 10 is manufactured. When the magnetic element 12 is a powder, a random density (change in density) of the powder is added to the scanning area 17, a random pattern is drawn with the density of the powder kept constant, or a combination of both of them is used. I put them together.

The scanning / detecting step S2 includes a scanning step S3 and a detecting step S4, and the object 10 to be detected is moved in the direction of arrow F at a predetermined speed by the transfer mechanism 26, so that detection according to the scanning area 17 is performed. The signal is obtained.

That is, in the scanning step S3, when the object 10 to be detected is moved by the transfer mechanism 26 in the direction of the arrow F at a predetermined speed, a plurality of minute portions of the scanning region 17 are MR-converted.
It passes through the vicinity of the elements 40 and 41 sequentially. At this time, since the magnetic flux passing through the MR elements 40 and 41 changes with time according to the distribution state of the magnetic element 12 and the like, a difference occurs in the resistance values R ₁ and R ₂ of the MR elements 40 and 41. Output voltage V
_out is measured as a unique output voltage pattern.

The above-mentioned detection signal is detected by dividing the scanning region 17 by every minute time, and the output voltage at each minute time is digitized by ranking in a plurality of stages. In this way, a coded detection signal specific to the scanning area 17 is obtained. In this manufacturing process, the first detection element pair 3
The detection signal of No. 1 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 above-described production process. One detection waveform is created from the obtained two types of detection waveforms by an interpolation method or the like.

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 is
In the writing step S6, the code is recorded on the code display section 18 by the magnetic head of the code writing section 51. The code display section 18 of this embodiment is a magnetic band, but the code code is displayed on the code display section 18 using a print head, for example.
You may make it record it by a bar code in. The encryption code may be stored in the code storage area of the host computer.

The processing device 20 is also used to check whether the detected object 10 is authentic or not. FIG. 7 shows an outline of the matching process for checking the authenticity of the detected object 10. Step S11 includes the scanning step S3 and the detection step S4 similar to the above-described process of creating the detected object 10. The magnetic element 12 is scanned by scanning the scanning region 17 with the sensor 30 at a predetermined speed.
A detection signal is obtained according to the distribution and the like. 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 pairs 32 and 33 are taken into the controller 50.

In the code reading step S12, the code reading section 52 reads the cipher code recorded in the code display section 18. This cipher code is the cipher code converter 62 in the code reproducing step S13.
The verification code is reproduced by being decoded according to a predetermined rule. Then, in a discrimination step S14, the three types of detection signals are compared with the collation code by the comparator 61. Then, when at least one of the detection signals (plurality) is within an allowable level for the collation code, it is determined that the detected object 10 is a genuine product, and the collation result is displayed on the display 65. It

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 of the sensor 30 is allowed by the amount of the second detection element pair 32 and 33 provided at the time of matching. The range can be expanded. For this reason,
There is no need to align the sensor 30 with high precision,
The processing device 20 is easily manufactured. When only the first detection element pair 31 and one second detection element pair 32 are used, the detection element pair 3 is determined in the determination step S14.
The two types of detection signals detected by the reference numerals 1 and 32 are compared with the collation code, and when any one of these detection signals is within an allowable level with respect to the collation code, the detected object 10 is a genuine article. Is judged.

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 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 matched with the encryption code read in the code reading step S12.

Further, like the detection section (sensor) 30 shown in FIG. 8, the element 4 of the plurality of detection element pairs 31, 32, 33 is arranged.
You may arrange so that 0 and 41 may enter mutually. In this way, a plurality of detection element pairs can be made compact and the cost can be reduced.

[0043]

According to the present invention, the permissible positional deviation of the detection unit at the time of collation is expanded as compared with the conventional device, and the reproducibility of the detection signal can be improved even if the detection unit is not aligned with high accuracy. high. Therefore, even if the detection unit used when creating / issuing the detected object differs from the detection unit used for matching,
It is possible to check with high reliability whether or not the detected object is authentic. Further, since it is not necessary to make the position of the detection unit highly accurate as compared with the conventional case, the cost of the device can be reduced.

[Brief description of drawings]

FIG. 1 is a plan view of a detection unit of a processing device showing an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an operation of a part of the detection unit shown in FIG.

FIG. 3 is a diagram showing a positional deviation allowable range and data reproducibility of the detection unit shown in FIG.

FIG. 4 is a plan view conceptually showing an example of an object to be detected.

5 is a side view showing, in a partial cross section, an outline of a processing apparatus including the detection unit shown in FIG.

FIG. 6 is a flowchart showing steps of processing when creating an object to be detected.

FIG. 7 is a flowchart showing steps of a process for collating an object to be detected.

FIG. 8 is a plan view showing a modified example of the detection unit.

[Explanation of symbols]

 10 ... Object to be detected 11 ... Base material 12 ... Magnetic element 17 ... Scan area 18 ... Code display section 20 ... Processing device 30 ... Magnetic sensor (detection section) 31 ... First detection element pair 32, 33 ... Second detection Element pair 40, 41 ... Magnetoelectric conversion element (MR element) 43 ... Magnetic field generating means (magnet) 50 ... Controller 51 ... Code writing section 52 ... Code reading section. 66 ... Switching circuit (switching means)

Claims (6)

[Claims] 1. An apparatus for checking the authenticity of an object to be detected 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. A magnetic field detecting element for magnetically detecting the magnetic field of the scanning region, and the detecting portion includes a pair of magnetoelectric conversion elements facing in a direction intersecting the scanning direction of the scanning region, the first magnetic element being arranged in the scanning direction.
And a second detection element pair arranged at a position displaced in a direction parallel to the first detection element pair, the authenticity of an object to be detected is characterized by: Device for checking. 2. An apparatus for checking the authenticity of an object to be detected according to claim 1, wherein the magnetoelectric conversion element used for the detection element pair is an MR element. 3. The amount of displacement of the second detection element pair with respect to the first detection element pair is in the range of 7% to 20% of the element width of the MR element. An apparatus for checking the authenticity of the object to be detected according to 2. 4. Two pairs of said second detection elements are used, and these second detection element pairs are arranged on opposite sides in the direction parallel to the first detection element pair, and are displaced by the same distance. The device for checking the authenticity of an object to be detected according to claim 2. 5. An apparatus for checking the authenticity of an object to be detected, which has 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. A magnetic detection means having a detection portion for magnetically detecting the magnetic field, and a transfer means for moving the object to be detected relative to the detection portion in a direction of scanning the scanning region. The dynamic detection means includes a first detection element pair in which a pair of magnetoelectric conversion elements facing a direction intersecting the scanning direction of the detection unit are arranged in the scanning direction, and a direction parallel to the first detection element pair. A second detection element pair arranged at a different position, a magnetic field generating means for applying a magnetic field to each detection element pair, and a magnetic element generated in the detection element pair when the magnetic element passes in the vicinity of each detection element pair. Detects changes in electrical output A detection circuit that obtains an output signal, and the first detection element when the detection signal obtained by the first detection element when issuing the detection object is taken into the detection circuit and the detection object is collated. Switching means for taking in the detection signal obtained by the pair and the second detection element pair into the detection circuit, and code writing means for recording the data related to the detection signal obtained by the first detection element pair in the code display section. Reading means for reading the data recorded in the code display portion, and comparing the data of the code display portion read by the reading means with detection signals obtained by all the detection element pairs and Means for determining that the detected object is authentic when any one of the detected signals corresponds to the data of the code display section, Apparatus for checking the correctness. 6. A method for checking the authenticity of an object to be detected, which 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. Including a creation process for creating an object, and a matching process for checking the object to be detected, wherein a pair of magnetoelectric conversion elements are arranged in the scanning direction in a processing device used in the creation process and the matching process. One detection element pair and a second detection element pair that is arranged in a direction parallel to the first detection element pair and are displaced from each other are provided. And a scanning step of applying a magnetic field to the first detection element pair while relatively moving the scanning region, and an electrical generated in the first detection element pair when the magnetic element passes in the vicinity of the first detection element pair. Output change And a step of recording the data related to the detection signal in a code display section, wherein the matching process includes moving the scanning area relative to each detection element pair. However, a scanning step of applying a magnetic field to the first detection element pair and the second detection element pair, and detection of all of these when the magnetic element passes in the vicinity of the first detection element pair and the second detection element pair. A detection step of obtaining a detection signal by detecting a change in an electrical output generated in the element pair, and a detection signal by the first detection element pair and the second detection element pair detected in the detection step is recorded in the code display section. This detected object is compared with the data being recorded and any one of the plurality of detection signals is within an allowable level for the data recorded in the code display section. The method for checking the authenticity of the object to be detected, characterized in that it comprises a determination step of determining as authentic.