JP4846413B2 - Detection tag detection device and non-detection region forming device - Google Patents

Description

  The present invention relates to a detection tag detection device and a non-detection region forming device that detect the presence of a detection tag in a detection region covered with an alternating magnetic field, and can be applied to, for example, a detection tag detection gate for shoplifting prevention. is there.

  For example, in a shoplifting prevention device, when a purchaser of a product with a detection tag attached normally passes between two detection tag detection gates, the detection tag detection gate side is obtained from the detection tag. Based on the data, it is determined whether or not payment has been completed. For example, it is possible to determine whether or not payment has been completed by changing the detection tag to a state in which communication is not possible after payment is completed.

Here, there is one using a magnetic field for communication between a detection tag and a detection tag detection gate (see Patent Document 1). In order to detect a detection tag according to a communication method (generally referred to as an EM method) using such a magnetic field, conventionally, for example, detection of two flat plates having a width of about 70 cm and a height of about 150 cm The tag detection gates were installed in parallel with a distance of about 1 m.
JP-A-6-342065

  In the conventional detection tag detection gate described above, the generated magnetic field is isotropic on both the front and back surfaces of the detection tag detection unit 2 as shown in FIG. , The presence or absence of the detection tag will be detected on both sides without the front and back. However, depending on the installation environment, there is a case where it is desired to make detection possible only on one side. For example, in a cash register of a store arranged in parallel, if a detection tag detection gate is provided between adjacent cash registers, for a detection tag passing through a cash register on the opposite side of the cash register on the region side to be detected. May react.

  In this case, a technique is adopted in which a metal plate such as an aluminum plate is installed on the non-detection region side that is not desired to be detected to shield the magnetic field on the non-detection side. However, this method is based on the principle that the magnetic plate is absorbed and shielded by generating an eddy current in the metal plate. Therefore, the eddy current generated in the metal plate becomes a noise source.

  As a result, there is a problem that the detection accuracy in the detection region that is actually desired to be detected is lowered.

  The present invention has been made in view of the above points, and an object thereof is to provide a detection tag detection device and a non-detection region forming device that can form a non-detection region while maintaining detection accuracy on the detection side. .

  In order to solve such a problem, the detection tag detection device of the present invention according to claim 1 is an AC magnetic field generating means for generating an AC magnetic field, an electric signal converting means for converting the intensity of a near magnetic field into an electric signal, and the AC A magnetic field distortion detecting means for detecting the distortion of the magnetic field due to the presence of the detection tag in the detection area covered with the alternating magnetic field generated by the magnetic field generating means based on the electric signal converted by the electric signal converting means; and the alternating current A non-detection region forming unit that makes any region of the detection region formed by the magnetic field generating unit a non-detection region, and the non-detection region forming unit is provided on the non-detection region side of the AC magnetic field generation unit. A DC magnetic field generating means for generating a DC magnetic field for making an arbitrary area of the detection area formed by the AC magnetic field generating means into a non-detection area is provided.

  With this configuration, the DC magnetic field generating means of the non-detecting area forming means provided on the non-detecting area side generates a DC magnetic field, and the DC magnetic field is an arbitrary detection area formed by the AC magnetic field generating means. This area is set as a non-detection area.

  The invention of claim 2 is characterized in that the DC magnetic field generating means of the non-detection region forming means is provided at a distance of 1 cm or more from the AC magnetic field generating means.

  With the above configuration, the DC magnetic field generating means provided at a distance of 1 cm or more on the non-detecting area side of the AC magnetic field generating means generates a DC magnetic field to form a non-detecting area.

  The invention of claim 3 is characterized in that the DC magnetic field generating means of the non-detection region forming means functions as a detection tag revocation device.

  With this configuration, the DC magnetic field generating unit functions as a revocation device, and revokes the detection tag when the detection tag passes through the non-detection region.

  The invention of claim 4 is characterized in that the AC magnetic field generating means is a magnetic field generating coil.

  With the above configuration, a current is appropriately passed through the magnetic field generating coil of the AC magnetic field generating means to generate an AC magnetic field having a predetermined strength.

  The invention of claim 5 is characterized in that the electric signal converting means is a loop antenna.

  With the configuration, the intensity of the alternating magnetic field is converted into an electric signal by the loop antenna, and the presence of the detection tag is detected by detecting the distortion of the alternating magnetic field by the magnetic field distortion detecting means based on the electric signal.

  The invention of claim 6 is characterized in that the DC magnetic field generating means is a magnetic field generating coil.

  With this configuration, a current is appropriately passed through the magnetic field generating coil of the DC magnetic field generating means to generate a DC magnetic field having a predetermined strength.

  In the invention of claim 7, the control of the DC magnetic field generating means of the non-detection area forming means and the control of the AC magnetic field generating means are interchanged, and the detection area and the non-detection area are appropriately changed.

  With the above configuration, when it is desired to change the detection area so far to a non-detection area, the control of each of the magnetic field generation means is exchanged to generate a DC magnetic field in the AC magnetic field generation means that has previously generated an AC magnetic field. An AC magnetic field is generated in the DC magnetic field generating means that has generated the magnetic field. As a result, the detection area and the non-detection area are changed.

  The invention of claim 8 is characterized in that the DC magnetic field generating means of the non-detection region forming means is composed of a permanent magnet.

  With the above configuration, the permanent magnet generates a stable DC magnetic field and forms the non-detection region.

  According to the ninth aspect of the present invention, among the detection regions for detecting the presence of the detection tag by generating an alternating magnetic field and detecting the distortion of the alternating magnetic field due to the detection tag present in the alternating magnetic field, A non-detection region forming apparatus for forming a non-detection region that does not detect presence, comprising a DC magnetic field generating means for generating a DC magnetic field for making any region of the detection region a non-detection region. To do.

  With the above configuration, the DC magnetic field generating means generates a DC magnetic field and makes any region of the detection region a non-detection region.

  The invention of claim 10 is characterized in that the DC magnetic field generating means is constituted by a magnetic field generating coil.

  With the above configuration, the non-detection region is formed by causing a direct current to flow through a magnetic field generating coil of the direct-current magnetic field generating unit as appropriate to generate a direct-current magnetic field.

  The invention of claim 11 is characterized in that the DC magnetic field generating means is constituted by a permanent magnet.

  With the above configuration, the permanent magnet generates a stable DC magnetic field and forms the non-detection region.

  The DC magnetic field generated by the DC magnetic field generating means of the non-detecting area forming means provided on the non-detecting area side is non-detecting any area on the detection area side formed by the magnetic field generated by the AC magnetic field generating means. Because it is an area, the detection tag is not detected in the non-detection area.

  The DC magnetic field generation means provided at a distance of 1 cm or more on the non-detection area side of the AC magnetic field generation means generates a DC magnetic field to form the non-detection area, so that the detection accuracy in the detection area is maintained. In this state, the detection tag is not detected in the non-detection area.

  Since the DC magnetic field generating means functions as a deactivation device and deactivates the detection tag, it is possible to prevent an erroneous reaction with respect to the processed detection tag.

  Since an AC magnetic field is generated by appropriately passing a current through the magnetic field generating coil of the AC magnetic field generating means, an AC magnetic field having a predetermined strength can be easily generated. Further, since a DC magnetic field is generated by appropriately flowing a current through the magnetic field generating coil of the DC magnetic field generating means, a DC magnetic field having a predetermined strength can be easily generated.

  The presence of the detection tag is surely detected by detecting the presence of the detection tag by converting the alternating magnetic field intensity into an electric signal by the loop antenna and detecting the distortion of the alternating magnetic field by the magnetic field distortion detection means based on the electric signal. Can be detected.

  Since the control of the DC magnetic field generating means and the control of the AC magnetic field generating means of the non-detection area forming means are interchanged, the detection area and the non-detection area are appropriately changed. Can be set.

  Since the DC magnetic field generating means of the non-detection area forming means is composed of a permanent magnet and generates a stable DC magnetic field, the non-detection area can be reliably formed.

  The DC magnetic field generating means of the non-detection area forming device generates a DC magnetic field, and the non-detection area can be formed in any area where the DC magnetic field generation means is provided.

  Since a DC magnetic field is generated by appropriately passing a current through the magnetic field generating coil of the DC magnetic field generating means of the non-detection region forming device, a DC magnetic field having a predetermined strength can be easily generated.

  Since the DC magnetic field generating means of the non-detection region forming apparatus is composed of a permanent magnet and generates a stable DC magnetic field, the non-detection region can be formed reliably.

  Hereinafter, an embodiment of the present invention will be described. In the present embodiment, a case where the detection tag detection device according to the present invention is applied to a detection tag detection gate device will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view showing the detection tag detection gate device of this embodiment from the front side. FIG. 3 is a perspective view showing the detection tag detection gate device of this embodiment from the back side.

  The detection tag detection gate device 1 of this embodiment includes a detection tag detection unit 2, a non-detection region formation unit 3, and an electrical processing unit 4.

  The detection tag detection unit 2 is a device for detecting a detection tag (not shown) existing in the detection area. The detection tag detection unit 2 is formed in a plate shape and includes an AC magnetic field generation unit 6 and an electric signal conversion unit 7. The detection tag detection unit 2 may be configured such that the AC magnetic field generation means 6 and the electric signal conversion means 7 are provided on the surface of a plate-like member such as wood, glass, or a synthetic resin panel, or two plate-like members. You may comprise so that the alternating current magnetic field generation means 6 and the electric signal conversion means 7 may be inserted | pinched. Although it does not specifically limit as a synthetic resin used for the said synthetic resin panel, For example, an acrylic type, a rubber type, a urethane type etc. can be mentioned. The thickness of the plate member is not particularly limited, and is preferably 1 cm to 10 cn, and may be appropriately selected in consideration of strength and the like. The detection tag is configured by stacking a soft magnetic material and a hard magnetic material.

  The AC magnetic field generating means 6 is a means for generating an AC magnetic field. The AC magnetic field generating means 6 is specifically constituted by a magnetic field generating coil. The AC magnetic field generating means 6 is wound, for example, in a rectangular shape whose vertical direction is 1200 mm and whose width direction (left and right direction) is 250 mm. The AC magnetic field generating means 6 generates an AC magnetic field by a driving AC current generated by the electric processing unit 4.

  Examples of the material for the magnetic field generating coil include coated conductors, conductive pastes and conductive inks, and metals such as gold, silver, copper, and aluminum.

  The number of windings is preferably 10 to 300 times, particularly preferably 50 to 200 times.

  The electric signal conversion means 7 is a device for converting the intensity of the near magnetic field into an electric signal. The electric signal converting means 7 is composed of two loop antennas 7A and 7B. The electric signal conversion means 7 converts the intensity of the alternating magnetic field passing through the loop antennas 7A and 7B into an electric signal.

  The two loop antennas 7 </ b> A and 7 </ b> B are provided on the same plane as the coil surface of the AC magnetic field generating means 6 and on the top and bottom of the coil surface of the AC magnetic field generating means 6. Each of the loop antennas 7A and 7B is wound in the same number, for example, in the shape of an ellipse having an upper and lower direction of 450 mm and a width direction (left and right direction) of 100 mm (upper and lower ends are arcs each having a radius of 40 mm).

  As the material of the loop antennas 7A and 7B, the same material as the magnetic field generating coil used in the AC magnetic field generating means 6 can be used. The number of windings is preferably 10 to 300 times, particularly preferably 50 to 200 times.

  Each of the loop antennas 7A and 7B is individually connected to the electric processing unit 4 or connected to the electric processing unit 4 in a state where the loop antennas 7A and 7B are connected in cascade as shown in FIG.

  FIG. 4 is an example of cascade connection in the case where the winding directions of two loop antennas 7A and 7B arranged separately in the upper and lower directions are the same, and the first output terminals (possibly positive and negative) of both loop antennas 7A and 7B. Are connected to each other, and the second output terminal (represented by “−”) of the loop antenna 7A is grounded, and the second output terminal of the loop antenna 7B is connected to the electric processing unit. Connect to 4.

  Here, when the induced voltages between the output terminals of the loop antennas 7A and 7B when there is no detection tag in the vicinity are V1 and V2, respectively, similar noise components are mixed in these induced voltages V1 and V2. The differential voltage V1-V2 input to the electrical processing unit 4 by the cascade connection as shown in FIG. When a detection tag exists in the vicinity, the induced voltage of the loop antenna 7A changes from V1 to V1 + ΔV1, the induced voltage of the loop antenna 7B changes from V2 to V2 + ΔV2, and the difference voltage input to the electric processing unit 4 is almost equal. ΔV1−ΔV2, and based on the temporal change of the difference voltage ΔV1−ΔV2, the magnetostriction generated when the detection tag that affects the magnetic field distribution is present can be monitored to detect the presence of the detection tag.

  If the loop antennas 7A and 7B are individually connected to the electrical processing unit 4, the electrical processing unit 4 includes, for example, a differential voltage in which an induced voltage difference between both output terminals of the loop antennas 7A and 7B is incorporated. Etc.

  The concept of detecting the presence of a detection tag in the vicinity based on the voltage difference between the induced voltages of the two loop antennas 7A and 7B is specifically described in JP-A-2005-38134. This example will be described with reference to FIG. In FIG. 5, reference numeral 100 denotes a detection tag detection gate, which is provided on the floor 102 in the building. In the detection tag detection gate 100, a magnetic field generation coil 104 made of a loop coil wound around the inner periphery of the detection tag detection gate 100 is attached. By supplying AC power with a predetermined frequency to the magnetic field generating coil 104, an AC magnetic field with a predetermined frequency is induced by the magnetic field generating coil 104.

  In the magnetic field generating coil 104, a plurality of (two in FIG. 5) loop antennas 106 and 108 are connected in series, and a first magnetic field detecting antenna 110 is constituted by these. The loop antenna 106 and the loop antenna 108 have loops wound in opposite directions. The terminal lead wire 112 of the loop antenna 108 is grounded, and one end 114 of the loop antenna 106 is connected to the input side of the output circuit 116.

  Below the first magnetic field detection antenna 110, a second magnetic field detection antenna 118 having the same configuration as that of the first magnetic field detection antenna 110 is provided. That is, loop antennas 120 and 122 wound in opposite directions are provided, and the terminal lead wire 124 of the loop antenna 122 is grounded. One end 126 of the loop antenna 118 is connected to the input side of the output circuit 116.

  The output circuit 116 has a circuit configuration for extracting a differential voltage between the output of the first magnetic field detection antenna 110 and the output of the second magnetic field detection antenna 118. Examples of the output circuit 116 include FIGS. 5B and 5C. The output circuit 116 in FIG. 5B amplifies and outputs the differential voltage between both outputs while canceling out noise using a differential amplifier circuit. V1 and V2 are output voltages of the magnetic field detection antennas 110 and 118, VOUT is an output voltage of the output circuit 116, and K is an amplification factor. The output circuit 116 in FIG. 5C is obtained by connecting the polarity of the output of the first magnetic field detection antenna 110 and the output of the second magnetic field detection antenna 118 in series with the polarity reversed. The operation is the same as that of the dynamic amplification circuit.

  The electric processing unit 4 in FIGS. 1 and 3 drives the AC magnetic field generating means 6 to generate an AC magnetic field and takes in the above-described differential voltage. The electric processing unit 4 is integrally incorporated with magnetic field distortion detection means 8 for determining whether or not a detection tag that affects the magnetic field distribution exists in the vicinity based on the differential voltage. The electrical processing unit 4 may be, for example, a unit that converts the differential voltage into a digital signal and transmits the digital signal to the host device. The electric processing unit 4 is also a base that supports the detection tag detection unit 2 and the non-detection region forming unit 3. The electric processing unit 4 supports the detection tag detection unit 2 and the non-detection region forming unit 3 with a distance of 1 cm or more. Here, the detection tag detection unit 2 and the non-detection region forming unit 3 are supported at a distance of 10 cm.

  The magnetic field distortion detecting means 8 is based on the electric signal converted by the electric signal converting means 7 for distortion of the magnetic field due to the presence of the detection tag in the detection area covered with the AC magnetic field generated by the AC magnetic field generating means 6. It is a device for detection. The magnetic field distortion detection means 8 is a known device configured by an electronic circuit or the like, and is incorporated in the electric processing unit 4.

  The non-detection region forming unit 3 is a non-detection region forming unit for forming a non-detection region that does not detect the detection tag other than the detection region formed by the AC magnetic field generated by the AC magnetic field generation unit 6. The non-detection region forming unit 3 is provided with a DC magnetic field generation unit 10 that is provided on the non-detection region side of the AC magnetic field generation unit 6 and generates a DC magnetic field.

  The DC magnetic field generating means 10 is composed of a magnetic field generating coil. The DC magnetic field generating means 10 is wound, for example, in a substantially rectangular shape having a vertical direction of 1200 mm and a width direction (left-right direction) of 410 mm. The size and number of turns of the magnetic field generating coil of the DC magnetic field generating means 10 are set according to the strength of the DC magnetic field to be generated. As the magnetic field generating coil constituting the DC magnetic field generating means 10, the same magnetic field generating coil as that used for the AC magnetic field generating means 6 can be used. The number of windings is preferably 10 to 300 times, particularly preferably 50 to 200 times. The DC magnetic field generating means 10 generates a DC magnetic field by driving (DC current) by the electric processing unit 4. By magnetizing the hard magnetic material of the detection tag by the DC magnetic field of the DC magnetic field generating means 10, no magnetostriction signal is generated. A direct-current magnetic field is also generated on the detection region side. However, by supporting the detection tag detection unit 2 and the non-detection region forming unit 3 with a distance of 1 cm or more, the hard magnetic material of the detection tag is magnetized in the non-detection region. It is possible to generate a direct-current magnetic field having such a strength that the hard magnetic material of the detection tag cannot be magnetized in the detection region. As a result, as shown in FIG. 6, the detection tag detection unit 2 and the non-detection region forming unit 3 form the detection region 21 and the non-detection region 22, and the detection tag is not detected in the non-detection region 22. .

  The detection tag detection gate device 1 configured as described above operates as follows.

  The AC magnetic field generating means 6 is driven by the electric processing unit 4 to generate an AC magnetic field on both the front and rear surfaces (detection region and non-detection region) of the detection tag detection unit 2.

  At the same time, the DC magnetic field generating means 10 of the non-detection region forming unit 3 is driven by the electric processing unit 4 to generate a DC magnetic field on both the front and back surfaces (detection region and non-detection region) of the non-detection region forming unit 3. Let The DC magnetic field generated by the DC magnetic field generating means 10 is located 1 cm or more closer to the non-detection area than the AC magnetic field generated by the AC magnetic field generating means 6 of the detection tag detection unit 2. A strong DC magnetic field is generated. The detection tag is magnetized by the DC magnetic field, the magnetostriction signal is attenuated, and a non-detection region is formed.

  In this state, when the detection tag is located in the detection region, the AC magnetic field is distorted thereby. Due to the distortion of the alternating magnetic field, the electric signal converted by the electric signal converting means 7 changes. The magnetic field distortion detection means 8 detects the distortion of the AC magnetic field based on the change of the electric signal due to the distortion of the AC magnetic field, and detects the presence of the detection tag.

  On the other hand, when the detection tag is located even in the non-detection region, the AC magnetic field is distorted by the detection tag as in the detection region, but the detection tag is magnetized in the non-detection region, and the degree of distortion of the AC magnetic field is also weakened. As a result, the detection tag is not detected in the non-detection area.

  Further, when the non-detection area is used as a detection tag revocation device, it is set so as to generate a direct-current magnetic field having a corresponding strength. The distance through which the detection tag passes is also set according to the strength of the DC magnetic field. Thereby, the detection tag is passed through the non-detection area, and the detection tag is expired.

  When it is desired to switch the detection area and the non-detection area, the electric processing unit 4 controls the DC magnetic field generation means 10 of the non-detection area forming unit 3 and the AC magnetic field generation means 6 of the detection tag detection unit 2. Are switched (exchange of alternating current and direct current).

  As a result, a DC magnetic field is generated by the AC magnetic field generating means 6, an AC magnetic field is generated by the DC magnetic field generating means 10, and the detection area and the non-detection area are switched. At this time, the strengths of the DC magnetic field and the AC magnetic field are appropriately adjusted by control by the electric processing unit 4.

[Experimental example]
Next, a specific experimental example of the detection tag detection gate device 1 having the above-described configuration will be described.

  Here, as the detection tag detection unit 2, a detection tag detection gate EG-C30 (EM Gate manufactured by Lintec Corporation) was used. As the non-detection region forming part 3, a detection tag detection gate EG-C45 (EM gate manufactured by Lintec Corporation) was used. The dimensions of the AC magnetic field generating means 6 of the EG-C30 are wound in a rectangular shape having a vertical direction of 1200 mm and a width direction (horizontal direction) of 250 mm. In addition, the loop antennas 7A and 7B of the electric signal converting means 7 are wound in the same number in the shape of an ellipse (upper and lower ends are arcs each having a radius of 40 mm) of 450 mm in the vertical direction and 100 mm in the width direction (left and right direction). It has been turned.

  The direct current magnetic field generating means 10 is obtained by passing a direct current through the magnetic field generating coil of the non-detection region forming unit 3 of the EG-C45. The DC magnetic field generating means 10 is wound in a substantially rectangular shape with 1200 mm in the vertical direction and 410 mm in the width direction (left and right direction).

  The EG-C45 also has loop antennas corresponding to the loop antennas 7A and 7B of the electric signal conversion means 7 of the EG-C30. However, in this experiment, no current flows and the loop antenna of the EG-C45 is used. Not done.

  The detection tag detection gate EG-C30 and the detection tag detection gate EG-C45 were set 10 cm apart. Detection tag EH-026 (Lintec EM tag) is 10cm from detection tag detection gate EG-C45 (non-detection region forming part 3) side or detection tag detection gate EG-C30 (detection tag detection part 2) side And 45 cm away.

  In the measurement, the signals (voltage values) obtained by the loop antenna 7A and the loop antenna 7B of the electric signal conversion means 7 of the detection tag detection gate EG-C30 (detection tag detection unit 2) are Fourier-exchanged to obtain an oscillation frequency of 3, The largest of the 4th and 5th harmonic signals was taken as the measured value. Furthermore, the presence or absence of detection with the detection tag detection gate EG-C30 was confirmed.

Experimental example 1
The AC magnetic field generating means 6 of the detection tag detection gate EG-C30 (detection tag detection section 2) is supplied with 1 ampere of alternating current, and the detection tag detection gate EG-C45 (non-detection area forming section 3) is a DC magnetic field generation means. A 10 ampere direct current was passed through 10.

Experimental example 2
Measurements were performed in the same manner as in Experimental Example 1 except that a 2 ampere DC current was passed through the DC magnetic field generating means 10.

Experimental example 3
Measurement was performed in the same manner as in Experimental Example 1 except that no current was passed through the DC magnetic field generating means 10.

The measured results are shown in Table 1.

  As can be seen from Table 1, in Examples 1 and 2, the detection tag was not detected in the non-detection region, and the obtained signal was low. In the detection area, the signal obtained was strong and the detection tag was also detected. On the other hand, in the comparative example, the detection tag was detected in both the non-detection area and the detection area, and the obtained signal was strong.

[effect]
As described above, the DC magnetic field generating means 10 of the non-detection area forming unit 3 provided on the non-detection area side of the AC magnetic field generation means 6 generates a DC magnetic field to form the non-detection area. Can do. As a result, it is possible to prevent the detection tag from being erroneously detected in the non-detection region.

  The DC magnetic field generating means 10 provided at a distance of 1 cm or more (10 cm in the experimental example) on the non-detection area side of the AC magnetic field generation means 6 generates a strong DC magnetic field in the non-detection area, thereby detecting the detection area. Thus, it is possible to form the non-detection region while maintaining the detection accuracy at. As a result, it is possible to prevent the detection tag from being erroneously detected in the non-detection region.

  The detection tag reacts with an alternating magnetic field in the detection region to generate an alternating magnetic field distortion, and the presence of the detection tag can be detected by detecting the distortion. Furthermore, since the DC magnetic field generating means 10 functions as a revocation device and revokes the detection tag, it can be prevented from reacting to the detection tag.

  Since an AC magnetic field or a DC magnetic field is generated by appropriately passing an electric current through the magnetic field generating coils of the AC magnetic field generating means 6 and the DC magnetic field generating means 10, an AC or DC magnetic field having a predetermined strength can be easily generated. As a result, an AC or DC magnetic field having an optimum strength can be generated according to various conditions such as the installation location, and a detection region and a non-detection region can be formed according to the installation location of the detection tag detection gate device 1. . That is, along with the adjustment of the distance between the AC magnetic field generating means 6 and the DC magnetic field generating means 10, the intensity of the AC or DC magnetic field is adjusted so that the detection area and the non-detection area corresponding to the required conditions such as the installation location can be obtained. Can be formed.

  The intensity of the alternating magnetic field in each of the loop antennas 7A and 7B of the electric signal converting means 7 is converted into an electric signal, and the distortion of the alternating magnetic field is detected by the magnetic field distortion detecting means 8 based on the electric signal, so that it is surely detected in the detection region. The presence of the detection tag can be detected.

  Since the control of the DC magnetic field generation means 10 of the non-detection area forming unit 3 and the control of the AC magnetic field generation means 6 of the detection tag detection unit 2 are interchanged, the detection area and the non-detection area are appropriately changed. The detection area can be set on either the front or back side of the detection tag detection gate device 1. As a result, the detection area can be set according to various conditions such as the usage mode.

[Modification]
In the said embodiment, although the electric processing part 4 was used as a base which supports the detection tag detection part 2 and the non-detection area | region formation part 3, you may use another board | plate material etc. as a base.

  Moreover, as a base, while supporting the detection tag detection part 2 and the non-detection area | region formation part 3, you may provide the space | interval adjustment mechanism which can adjust the space | interval of these detection tag detection parts 2 and the non-detection area | region formation part 3. As this distance adjusting mechanism, a known technique such as an adjusting screw can be used.

  In the embodiment, the non-detection region forming unit 3 that forms the non-detection region is provided integrally with the detection tag detection unit 2 by the electric processing unit 4, but as a separate member from the detection tag detection unit 2. It is good also as a separated structure. That is, a non-detection region forming device that forms a non-detection region that does not detect the presence of the detection tag in the detection region may be provided in the vicinity of the detection tag detection unit 2 at a position where the non-detection region is to be formed. For example, as shown in FIG. 7, a non-detection region forming device 12 including the DC magnetic field generating means 10 is provided in the vicinity of the detection tag detection gate device 11 including only the detection tag detection unit 2. You may make it form a non-detection area | region in the detection area formation apparatus 12 on the opposite side (right side of FIG. 7) of the gate apparatus 11 for detection tag detection.

  Moreover, as shown in FIG. 8, you may make it provide the non-detection area | region formation apparatus 13 in the position of the two places of the one side of the detection tag detection gate apparatus 11. FIG. Furthermore, as shown in FIG. 9, the non-detection region forming device 14 may be provided obliquely at two positions on one side of the detection tag detection gate device 11. In this case, a detection tag non-detection region is formed in the vicinity of the non-detection region forming device 14 having a sufficient DC magnetic field strength.

  Furthermore, not only in the flat detection tag detection gate device, but also in the case of a cylindrical detection tag detection gate device 16 that forms a detection region by generating a magnetic field in all directions as shown in FIG. A non-detection region forming device 17 may be provided at a position where a region is desired to be formed, and a non-detection region may be formed on the opposite side of the detection tag detection gate device 16 in the non-detection region forming device 17. Further, the size, number, etc. of the non-detection region forming device 17 are also set as appropriate according to the number, size, etc. of non-detection regions to be formed.

  In these cases, the same operations and effects as those of the above embodiment can be obtained.

  Further, the DC magnetic field generating means 10 of the non-detection region forming unit 3 may be constituted by a permanent magnet instead of the magnetic field generating coil. Thus, by forming the DC magnetic field generating means 10 of the non-detection region forming unit 3 with a permanent magnet, a stable DC magnetic field is generated, so that the non-detection region can be reliably formed. The permanent magnet is not particularly limited as long as it is a hard magnetic material. For example, magnets such as carbon steel, iron, nickel, ferrite series, ferrite alloy series, ferrichrome series, alnico series, and rare earth series are used. I can do it.

  In the embodiment, the detection tag detection gate device 1 has been described as an example of the detection tag detection device. However, the present invention is not limited to this, and all detection tags need to be detected in the detection region while avoiding the non-detection region. It can be applied to other devices.

  In the above-described embodiment, the detection tag detection unit 2 and the non-detection region forming unit 3 are disposed with a distance of 1 cm. The interval of 1 cm is a non-detection region while maintaining the detection accuracy in the detection region. It is the space | interval which can form. If the distance between the detection tag detection unit 2 and the non-detection region forming unit 3 is less than 1 cm, the detection accuracy in the detection region may not be maintained.

It is a perspective view which shows the gate apparatus for detection tag detection which concerns on embodiment of this invention from the front side. It is an image figure which shows the conventional detection area. It is a perspective view which shows the gate apparatus for detection tag detection which concerns on embodiment of this invention from the back side. It is a block diagram which shows the example of a connection of two loop antennas which concern on embodiment of this invention. It is a schematic explanatory drawing of the detection tag detection gate. It is an image figure which shows the detection area | region and non-detection area | region of this invention. It is a schematic block diagram which shows a 1st modification. It is a schematic block diagram which shows a 2nd modification. It is a schematic block diagram which shows a 3rd modification. It is a schematic block diagram which shows a 4th modification.

Explanation of symbols

1: detection tag detection gate device, 2: detection tag detection unit, 3: non-detection region formation unit, 4: electric processing unit, 6: AC magnetic field generation unit, 7: electric signal conversion unit, 7A: loop antenna, 7B : Loop antenna, 8: magnetic field distortion detection means, 10: DC magnetic field generation means, 21: detection area, 22: non-detection area.

Claims (11)

AC magnetic field generating means for generating an AC magnetic field;
Electrical signal conversion means for converting the intensity of the near magnetic field into an electrical signal;
Magnetic field distortion detection means for detecting the distortion of the magnetic field due to the presence of the detection tag in the detection region covered with the AC magnetic field generated by the AC magnetic field generation means, based on the electric signal converted by the electric signal conversion means,
Non-detection area forming means for making any area of the detection area formed by the AC magnetic field generating means into a non-detection area,
The non-detection area forming means is provided on the non-detection area side of the AC magnetic field generation means, and generates a DC magnetic field for making any detection area formed by the AC magnetic field generation means into a non-detection area. A detection tag detection apparatus comprising a direct-current magnetic field generating means for causing a detection tag.   2. The detection tag detection device according to claim 1, wherein the direct-current magnetic field generation means of the non-detection region forming means is provided at a distance of 1 cm or more from the alternating-current magnetic field generation means.   3. The detection tag detection apparatus according to claim 1, wherein the DC magnetic field generation means of the non-detection area forming means functions as a detection tag revocation device.   4. The detection tag detection apparatus according to claim 1, wherein the AC magnetic field generation means is a magnetic field generation coil.   The detection tag detection device according to claim 1, wherein the electric signal conversion means is a loop antenna.   6. The detection tag detection apparatus according to claim 1, wherein the DC magnetic field generation means is a magnetic field generation coil.   7. The detection area and the non-detection area are appropriately changed by switching the control of the DC magnetic field generation means of the non-detection area forming means and the control of the AC magnetic field generation means. The detection tag detection apparatus according to item 1.   6. The detection tag detection device according to claim 1, wherein the DC magnetic field generation means of the non-detection region forming means is constituted by a permanent magnet. Non-detection region that does not detect the presence of the detection tag among detection regions that detect the presence of the detection tag by generating an alternating magnetic field and detecting distortion of the alternating magnetic field due to the detection tag existing in the alternating magnetic field A non-detection region forming device for forming
A non-detection region forming apparatus comprising a direct-current magnetic field generating means for generating a direct-current magnetic field for making an arbitrary region of the detection region a non-detection region.   The non-detection region forming apparatus according to claim 9, wherein the DC magnetic field generation unit includes a magnetic field generation coil. The non-detection region forming apparatus according to claim 10, wherein the DC magnetic field generating means is constituted by a permanent magnet.

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