JP5195563B2 - Detection tag, storage medium, and detection system - Google Patents

Description

  The present invention relates to a detection tag, a storage medium, and a detection system.

  There is a system that detects unauthorized take-out of a product by previously embedding a magnetic wire that causes a sharp magnetization reversal when an alternating magnetic field is applied. As an example of this system, there is an article management system described in Patent Document 1. In this article management system, a canceling magnetic body is provided near the magnetic wire to cancel the magnetization reversal function.

JP 2003-182847 A

  The present invention relates to a detection tag that can adjust an output value of a pulse signal generated when a magnetic material produces a large Barkhausen effect as needed without using a special device, a storage medium having the detection tag, and It is an object to provide a detection system having the detection tag.

  In the detection tag according to claim 1 of the present invention, the output value of the pulse signal generated when the large Barkhausen effect is generated can be adjusted to the magnetic body, and the magnetic body can be adjusted by applying stress. Stress applying means for applying stress.

  In the detection tag according to claim 2 of the present invention, the maximum stress applied to the magnetic body by the stress applying means is smaller than the elastic limit of the magnetic body.

  In the detection tag according to a third aspect of the present invention, the magnetic body is a magnetic wire embedded in a resin material, and the stress applying means applies an axial compressive stress to the resin material.

  In the detection tag according to a fourth aspect of the present invention, the magnetic body is a magnetic wire embedded in a resin material, and the stress applying means applies a tensile stress to the resin material.

  A storage medium according to a fifth aspect of the present invention includes a housing provided with the detection tag according to any one of the first to fourth aspects, and a storage unit that is provided in the housing and stores information. And a switching unit that is interlocked with the stress applying means and can switch permission and prohibition of writing of information to the storage unit, and applying the stress when the switching unit is switched to a state of prohibiting writing The stress on the magnetic body by the means is released.

  According to a sixth aspect of the present invention, there is provided a detection system comprising: the detection tag according to any one of the first to fourth aspects; and an alternating magnetic field having a strength at which a magnetic material of the detection tag produces a large Barkhausen effect. A magnetic field generating unit capable of generating, a signal detecting unit for detecting a pulse signal emitted from the magnetic body to which the alternating magnetic field is applied, and the detection tag when an output value of the pulse signal is equal to or larger than a preset set value. And a detecting device for notifying that it has been detected.

  According to the first aspect of the present invention, the output value of the pulse signal generated when the magnetic material produces the large Barkhausen effect can be adjusted as necessary without using a special device.

  According to the second aspect of the present invention, the magnetic material is restored by releasing the stress applied to the magnetic material, and the output value of the pulse signal can be recovered.

  According to the third aspect of the invention, the magnetic wire is less likely to buckle than when not embedded in the resin material, and the compressive stress applied to the magnetic wire can be easily adjusted.

  According to the invention of claim 4, the magnetic wire is less likely to bend and the tensile stress can be easily adjusted as compared with a case where the magnetic wire is not embedded in the resin material.

  According to the fifth aspect of the present invention, the large Barkhausen effect can be produced in the magnetic material in a state where writing of information to the storage medium is prohibited.

  The invention according to claim 6 can select notification or non-notification of the detection tag detected by the detection device by adjusting the output value of the pulse signal generated when the magnetic material produces the large Barkhausen effect. .

It is a partial sectional view which looked at a detection tag concerning a detection tag of a 1st embodiment and which has a slider in the 1st position from the upper part. It is the fragmentary sectional view which looked at the detection tag of FIG. 1 from the side. It is the fragmentary sectional view which looked at the detection tag which has a slider in the 2nd position from the upper part. (A) is a diagram which shows the hysteresis loop of the magnetic body which produces the large Barkhausen effect. (B) is a diagram which shows the alternating magnetic field applied to a magnetic body. (C) is a diagram which shows the pulse signal which the magnetic body to which the alternating magnetic field was applied emits. It is a diagram which shows the relationship between the axial direction compressive stress provided to the magnetic wire of 1st Embodiment, and the output voltage of the pulse signal which generate | occur | produces and produces the large Barkhausen effect in the state where the stress was provided. It is a schematic block diagram for demonstrating the detection system of 1st Embodiment. It is a partial sectional view which looked at a detection tag concerning a detection tag of a 2nd embodiment, and has a pressing member in the 1st position from the upper part. It is the fragmentary sectional view which looked at the detection tag of FIG. 7 from the side. It is the fragmentary sectional view which looked at the detection tag which has a pressing member in the 2nd position from the side. It is the top view which looked at the detection tag provided in the flexible disk concerning the detection tag of 3rd Embodiment from upper direction.

[First embodiment]
A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a partial cross-sectional view of the detection tag 10 according to the present embodiment as viewed from above, and FIG. 2 is a partial cross-sectional view of the detection tag 10 as viewed from the side. As shown in FIGS. 1 and 2, the detection tag 10 includes a case 12 having a rectangular parallelepiped shape, a magnetic wire 20 (an example of a magnetic body) disposed inside the case 12, A stress applying mechanism 30 (an example of a stress applying means) that is disposed inside and applies stress to the magnetic wire 20 in an adjustable manner.

  The housing 12 has an opening 12B formed on an upper surface 12A on one end side in the longitudinal direction (right side in FIG. 1), and an adhesive layer 12C provided on the bottom surface. The detection tag 10 of the present embodiment is attached to various articles using the adhesive layer 12C. If the detection tag is attached to an article, in addition to being attached with the adhesive layer 12C, the detection tag may be fixed with screws, clamped with a clip, or provided with a storage space on the article side and stored there. May be.

The magnetic wire 20 has magnetic characteristics that cause a large Barkhausen effect.
Here, the large Barkhausen effect will be briefly described. FIG. 4 is a diagram for explaining the large Barkhausen effect. The large Barkhausen effect has a BH characteristic as shown in FIG. 4A, that is, a material having a relatively small hysteresis loop and a relatively small coercive force (Hp), for example, Co—Fe—Ni—B—. This is a phenomenon in which a sharp magnetization reversal occurs when an amorphous magnetic material made of Si is placed in an alternating magnetic field having an amplitude equal to or greater than the coercive force (Hp). For this reason, when an alternating current is passed through an excitation coil 64 (an example of a magnetic field generation unit) described later to generate an alternating magnetic field having an amplitude greater than the holding force (Hp), the magnetic wire 20 is placed in the alternating magnetic field. During steep magnetization reversal, a detection coil 66 (an example of a signal detection unit), which will be described later, disposed in the vicinity of the magnetic wire 20 detects an electrical pulse signal.

  Here, for example, when an alternating magnetic field as shown in FIG. 4B is generated by the exciting coil 64, if the detection tag 10 is arranged in the generated alternating magnetic field, the detection coil 66 has a pulse shape. Current flows, and a pulsed output voltage (output value of the pulse signal) as shown in FIG. 4C is obtained.

On the other hand, the material of the magnetic wire 20 is generally a permanent magnet, for example, a rare earth-based neodymium (Nd) -iron (Fe) -boron (B) main component, samarium (Sm) -cobalt (Co). Main component, Alnico aluminum (Al) -Nickel (Ni) -Cobalt (Co) main component, Ferritic barium (Ba) or Strontium (Sr) and iron oxide (Fe ₂ O ₃ ) As the main component, soft magnetic materials, oxide soft magnetic materials, etc., but as a magnetic material that causes the above-mentioned large Barkhausen effect, the basic composition is Fe-Co-Si or Co-FeNi series It is preferable to use an amorphous magnetic material.

  In addition, the shape of the magnetic wire 20 is not particularly limited as long as it is a shape suitable for generating the large Barkhausen effect, but in order to generate the large Barkhausen effect, a predetermined length with respect to the cross-sectional area is required. Since it becomes necessary, a wire shape (line shape) or a belt shape is preferable. Further, the magnetic wire 20 of the present embodiment is made of an amorphous magnetic material (Fe—Co—B—Si), and has a diameter of 30 μm and a length of 2.5 cm.

  In addition, the magnetic wire 20 of the present embodiment has a characteristic that an output value (hereinafter, output voltage) of a pulse signal generated when a large Barkhausen effect is generated by applying stress is reduced. FIG. 5 shows a change in the output voltage (mV) when the axial compressive stress (Mpa) is applied to the magnetic wire 20. From FIG. 5, the magnetic wire 20 outputs when the axial compressive stress is increased. It can be seen that the voltage drops. Further, the output voltage is saturated after being lowered to some extent (in FIG. 5, it is saturated at around 50 mV). Here, when the axial compressive stress applied to the magnetic wire 20 does not exceed the elastic limit of the magnetic wire 20, the magnetic wire 20 is restored by releasing the axial compressive stress, as can be seen from FIG. In addition, the output voltage returns to the initial state before the axial compressive stress is applied. That is, the axial stress (stress) applied to the magnetic wire 20 is preferably smaller than the elastic limit of the magnetic wire 20.

  As shown in FIG. 1, the magnetic wire 20 is embedded in a synthetic resin material 22 (for example, a thermoplastic resin material, a thermosetting resin material, etc.), and one end portion of the synthetic resin material 22 is attached to the housing 12. It is fixed to the inner wall surface on the other end side in the longitudinal direction.

  The stress applying mechanism 30 is movable in the longitudinal direction of the housing 12, a substantially rectangular parallelepiped slider 34 in which the projecting operation portion 32 is exposed from the opening 12 </ b> B of the housing 12, and the slider 34 and the synthetic resin material 22. The slider 34 is compressed as the slider 34 moves from the first position shown in FIG. 1 to the second position shown in FIG. 3 and is applied to the magnetic wire 20 via the synthetic resin material 22. And a spring 40 for applying an axial compressive stress. When the slider 34 is in the first position, the axial compressive stress is not applied to the magnetic wire 20 by the spring 40, that is, the axial compressive stress shown in FIG. When the slider 34 is in the second position, the spring 40 applies, for example, 10 Mpa of axial compressive stress in the range of 6.6 to 30 Mpa shown in FIG. 5 to the magnetic wire 20. ing.

  The slider 34 is provided with a pair of hooks 36 that can be elastically deformed. When the slider 34 is moved to the second position, the pair of hooks 36 are elastically deformed to get over the protrusions 38 provided on the inner wall surface of the housing 12 and then restored, and are hooked on the protrusions 38. ing.

  In the present embodiment, the spring 40 is used to apply the axial compressive stress to the magnetic wire 20 via the synthetic resin material 22, but an elastic body such as rubber is used instead of the spring 40. It is good also as a structure which gives an axial direction compressive stress to the magnetic wire 20 via the synthetic resin material 22 with the restoring force of the elastic body compressed by the slider 34. FIG.

  Next, the detection system 50 for detecting the detection tag 10 of the present embodiment will be described. FIG. 6 shows a schematic configuration of the detection system 50 according to the present embodiment. The detection system 50 includes the detection tag 10 described above, and a detection device 60 including a gate antenna 52, a warning light 54, and a controller 56 that controls the operation thereof.

  As shown in FIG. 6, the detection system 50 is provided in a room S such as an office or a store. In the room S, a security gate 62 is provided at the entrance, and personnel can pass through the security gate 62 and go out of the room.

  Further, the security gate 62 is provided with a gate antenna 52 and a warning lamp 54. When the detection tag 10 is detected by the gate antenna 52, the warning lamp 54 is lit or blinks. Note that the notification method is not limited to this, and it may be performed by an alarm or voice, or may be displayed on a display provided in a preset location. A combination of notification means may be used.

  The gate antenna 52 includes an excitation coil 64 that generates an alternating magnetic field using electric power (AC power) supplied from the controller 56, and a detection coil that detects a pulse signal generated by the magnetic wire 20 with respect to the alternating magnetic field generated by the excitation coil 64. 66. That is, a current corresponding to the alternating magnetic field generated by the exciting coil 64 is induced in the detection coil 66 and a current corresponding to the pulse signal generated by the magnetic wire 20 is induced.

  The controller 56 detects a pulse signal generated by the magnetic wire 20 by removing a low frequency component corresponding to the period of the alternating magnetic field from the current induced in the detection coil 66. Further, the controller 56 notifies the warning lamp 54 that the detection tag 10 has been detected when the detected output voltage of the magnetic wire 20 is equal to or higher than a preset set value. The preset setting value is between the output voltage generated by the magnetic wire 20 when the slider 34 of the detection tag 10 is in the first position and the output voltage generated by the magnetic wire 20 when the slider 34 is in the second position. In this embodiment, for example, it is set to 500 mV.

  The controller 56 may always be in an operating state (a state in which an alternating magnetic field is generated), or an optical sensor or the like is provided in the security gate 62 to detect the passing timing of personnel using this optical sensor. It may shift to an operating state.

Next, the operation of the first embodiment will be described.
When the slider 34 of the detection tag 10 passes through the security gate 62 in the first position, the magnetic wire 20 produces a large Barkhausen effect by the alternating magnetic field generated from the excitation coil 64 of the gate antenna 52, and generates a pulse signal. A pulse signal is detected by the detection coil 66. The controller 56 calculates the output voltage of the detected pulse signal. Here, since the slider 34 is in the first position, the output voltage is higher than a preset value (500 mV), and the controller 56 lights or blinks the warning lamp 54.

  Then, when the slider 34 of the detection tag 10 is moved to the second position and passes through the security gate 62 again, the output voltage is lower than the preset set value (500 mV) because the slider 34 is in the second position. Thus, the controller 56 does not light or blink the warning light 54. Thus, the detection tag 10 or the article to which the detection tag 10 is attached can be taken out without being notified by the warning lamp 54.

  In the present embodiment, the slider 34 is releasably held at the first position and the second position. However, the slider is provided with a plurality of pairs of protrusions 38 so that the movement of the slider 34 can be adjusted in multiple stages. The movement of 34 may be held at a plurality of positions.

[Second Embodiment]
Next, 2nd Embodiment of the detection tag of this invention is described based on FIGS. In addition, about the same member as 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 7, the detection tag 80 according to the second embodiment includes a casing 82 whose outer shape is a rectangular parallelepiped, and a magnetic wire 20 embedded in a synthetic resin material 22 disposed inside the casing 82. And a stress applying mechanism 90 (an example of a stress applying means) that is disposed inside the casing 82 and applies stress to the magnetic wire 20.

  As shown in FIG. 8, the housing 82 includes a cylindrical portion 82B protruding from the center of the upper surface 82A, and an adhesive layer 82C is provided on the bottom surface. The detection tag 80 of the present embodiment is attached to various articles using the adhesive layer 82C.

  Further, both end portions of the synthetic resin material 22 are fixed to both inner wall surfaces in the longitudinal direction of the casing 82, and a gap is formed between the lower surface of the synthetic resin material 22 and the lower surface of the inner wall of the casing 82. ing.

  The stress applying mechanism 90 has a female screw 92 formed on the inner peripheral surface of the cylindrical portion 82B and a male screw 94 to be screwed into the female screw 92 on the outer peripheral surface, and an axial tip portion (an end on the magnetic wire 20 side). Part) has a pressing member 96 formed in a hemispherical shape.

  The female screw 92 prevents the pressing member 96 from coming out of the cylindrical portion 82B, and a stopper mechanism for preventing the movement of the pressing member 96 before the magnetic wire 20 pressed by the distal end portion of the pressing member 96 reaches the elastic limit. (Not shown).

  As shown in FIG. 7, a cross-shaped tool hole 98 for rotating the pressing member 96 is formed on the rear end surface of the pressing member 96. The tool hole 98 is formed in such a shape that the tip of a Phillips screwdriver fits. The tool hole 98 may be formed in such a shape that the tip of a tool such as a flat-blade screwdriver or a hexagon wrench can be fitted, or formed in a shape in which only the tip of a dedicated tool is fitted. May be.

Next, the operation of the second embodiment will be described.
As shown in FIG. 9, when the male screw 94 of the pressing member 96 is screwed into the female screw 92 of the cylindrical portion 82 </ b> B, the central portion of the synthetic resin material 22 is pressed at the tip of the pressing member 96, and the magnetic resin together with the synthetic resin material 22 is magnetic. The wire 20 is bent and an axial tensile stress is applied to the magnetic wire 20 supported at both ends via the synthetic resin material 22. Thereby, the output voltage when the magnetic wire 20 produces the large Barkhausen effect is lowered. The output voltage generated by the magnetic wire 20 when the large Barkhausen effect is produced is adjusted by adjusting the amount by which the pressing member 96 is screwed.

[Third embodiment]
Next, 3rd Embodiment of the detection tag of this invention is described based on FIG. In addition, about the same member as 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 10, the detection tag 110 of this embodiment is provided in a housing 122 of a general flexible disk 120 (hereinafter referred to as FD 120) as a storage medium. The slider 34 of the detection tag 110 (in this embodiment, an example of a switching unit) also serves as an information writing prevention slider that is generally provided in the FD 120. Specifically, the first position of the slider 34 corresponds to a write prevention position for the storage unit 124 of the FD 120, and the second position corresponds to a write permission position for the storage unit 124 of the FD 120. Note that a reading device (not shown) for reading information on the FD 120 optically detects the position of the slider 34 and determines whether or not writing of information to the FD 120 is permitted.

Next, the operation of the third embodiment will be described. When the user stores confidential information in the FD 120, the slider 34 is moved to the second position to allow writing of information. After the user stores confidential information in the FD 120, the slider 34 is moved to the first position. As a result, writing of information to the FD 120 is prevented, and an output voltage generated when the detection tag 110 produces a large Barkhausen effect is in an initial state. By doing in this way, when the FD 120 storing the confidential information is about to be taken out from the room S, the warning lamp 54 is lit or blinked, and it is notified that the confidential information is about to be taken out by mistake. . Thereby, it is suppressed that confidential information is leaked outside.

  In the third embodiment, the detection tag 110 is provided in the housing 122 of the FD 120. However, the present invention is not limited to this configuration, and may be provided in another storage medium. Examples of other storage media include a magnetic tape.

  In the first embodiment, the spring 40 and the slider 34 are used to apply the axial compressive stress to the magnetic wire 20. However, the present invention is not limited to this configuration, and the second embodiment. It is good also as a structure which gives an axial direction compressive stress to the magnetic wire 20 using the structure of the press member 96 and the internal thread 92 of this. Further, in the second embodiment, the spring 40 and the slider 34 are used to apply the axial tensile stress to the magnetic wire 20, but the present invention is not limited to this configuration, and the first embodiment is used. A configuration in which an axial tensile stress is applied to the magnetic wire 20 using the configuration of the spring 40 and the slider 34 may be adopted.

  In addition to the axial compressive stress and tensile stress, stress may be applied to the magnetic wire 20 by a method such as pressing the synthetic resin material 22 as a whole.

  The embodiments of the present invention have been described with reference to the embodiments. However, these embodiments are merely examples, and various modifications may be made without departing from the scope of the invention. It goes without saying that the scope of rights of the present invention is not limited to these embodiments.

10 detection tag 20 magnetic wire (magnetic wire (magnetic material))
22 Synthetic resin material (resin material)
30 Stress applying mechanism (stress applying means)
50 Detection System 60 Detection Device 64 Excitation Coil (Magnetic Field Generator)
66 Detection coil (signal detection part)
80 detection tag 90 stress applying mechanism (stress applying means)
110 Detection tag 120 Flexible disk (storage medium)
122 Case 124 Storage unit

Claims (6)

A magnetic material in which the output value of a pulse signal generated when a large Barkhausen effect occurs, and which is reduced by applying stress;
Stress applying means for applying an adjustable stress to the magnetic body;
Detection tag with   The detection tag according to claim 1, wherein a maximum stress applied to the magnetic body by the stress applying unit is smaller than an elastic limit of the magnetic body. The magnetic body is a magnetic wire embedded in a resin material,
The detection tag according to claim 1, wherein the stress applying unit applies an axial compressive stress to the resin material. The magnetic body is a magnetic wire embedded in a resin material,
The detection tag according to claim 1, wherein the stress applying unit applies tensile stress to the resin material. A housing provided with the detection tag according to any one of claims 1 to 4,
A storage unit provided in the housing for storing information;
In conjunction with the stress applying means, a switching unit capable of switching permission and prohibition of writing information to the storage unit;
Have
The storage medium according to claim 1, wherein when the switching unit is switched to a write-prohibited state, the stress applied to the magnetic material by the stress applying unit is released. The detection tag according to any one of claims 1 to 4,
A magnetic field generating unit capable of generating an alternating magnetic field having a strength that causes a large Barkhausen effect in the magnetic body of the detection tag, a signal detecting unit for detecting a pulse signal emitted from the magnetic body to which the alternating magnetic field is applied, and the pulse A detection device comprising notification means for notifying that the detection tag has been detected when the output value of the signal is greater than or equal to a preset setting value;
Detection system with

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