JP2008108003A - Security tag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-versatility security tag used for a security system such as an electronic article surveillance. <P>SOLUTION: This security tag has: a dielectric film 130; a resonant circuit comprising a pair of coil patterns 110, 120 formed on double-sided peripheral parts of the dielectric film; and a resonance part 150 installed in an area not formed with the coil pattern on one face of the dielectric film 130, using an electromechanical transducer having a resonance frequency different from the resonant circuit. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a security tag used in a security system such as an electronic article surveillance system (EAS: Electronic Article Surveillance).

  In recent years, electronic merchandise monitoring systems have been widely used for the purpose of preventing shoplifting. An electronic merchandise monitoring system is generally composed of a security tag (hereinafter referred to as “tag”) attached to each article to be monitored and a gate for detecting the tag. And a gate is arrange | positioned at the entrance of a store etc., for example, and a warning, such as a sound and light, is output when a tag is detected by a gate. A tag attached to an article to be monitored is configured to be invalidated by a user (for example, a store clerk) of the monitoring system, and a tag of an article that has undergone a legitimate procedure (for example, purchase) is invalidated and is not detected at the gate. In this way, it is possible to detect taking-out of articles that have not undergone purchase procedures.

Japanese Patent Laid-Open No. 11-3476

  In such an electronic merchandise monitoring system, it is necessary to attach a tag to each monitored item. Therefore, for example, when an electronic merchandise monitoring system is introduced into a retail store, a lot of labor is required to attach tags one by one to purchased merchandise. As a method of reducing the burden on such a retail store, it is conceivable to attach a tag at the time of manufacturing a product.

  However, another problem arises when trying to implement such a method. That is, the gate of the electronic merchandise monitoring system normally outputs a radio wave or magnetic field (hereinafter referred to as electromagnetic wave) having a predetermined specific frequency, and the tag is designed to resonate with the electromagnetic wave of the specific frequency. (Patent Document 1). Therefore, the tag and the gate have a close relationship with each other, and the electronic merchandise monitoring system cannot realize the function with the combination of the tag and the gate having different resonance frequencies and detection principles.

  Therefore, it is not possible to save the trouble of attaching the tag at the retail store unless the tag suitable for the electronic product monitoring system introduced by the retail store that delivers the product is attached. However, if the type of tag to be attached is changed according to the electronic merchandise monitoring system used by the merchandise delivery destination, the burden on the manufacturer side will be greatly increased.

  The present invention has been made in view of such problems of the conventional technology, and an object thereof is to provide a highly versatile security tag.

  The above-mentioned object is to provide a resonant circuit composed of a dielectric film and a pair of coil patterns made of a conductive thin film having a substantially uniform width provided on both peripheral edges of the dielectric film, and a dielectric This is achieved by a security tag that is attached to an area on one surface of the film where a coil pattern is not formed and has a resonance part that uses an electromechanical transducer having a resonance frequency different from the resonance circuit.

  In addition, the above-described object is to provide a resonance circuit having a configuration in which a pair of coil patterns made of a conductive thin film having a substantially uniform width are bonded together by a resin coating, a support member to which the entire resonance circuit is attached, and a support member The above is also achieved by a security tag that is attached to a region on the inner side of the coil pattern and has a resonance part that uses an electromechanical transducer having a resonance frequency different from the resonance circuit.

  With such a configuration, according to the present invention, a highly versatile security tag can be realized.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a top view illustrating a configuration example of a security tag according to an embodiment of the present invention, and FIG. 2 is a side view illustrating a configuration example of a security tag according to an embodiment of the present invention.

  In the figure, the tag 100 includes a dielectric film 130, a first coil pattern 110, a second coil pattern 120, a resonance part 150, and a mount 180. The mount 180 is not an essential component of the security tag but is provided as necessary as a reinforcing member, a member attached to an article, or the like.

  The dielectric film 130 is a resin film, for example. The first and second coil patterns 110 and 120 are provided on the periphery of the dielectric film 130, and are arranged so that a linear conductive thin film having a substantially uniform width over the entire length is rotated as much as possible so as not to overlap. Is. The first and second coil patterns 110 and 120 have a section facing each other with the dielectric film 130 in between, and this section (opposing section) serves as an electrode for the first and second coil patterns 110 and 120. Then, a capacitor using the dielectric film 130 sandwiched between the first and second coil patterns 110 and 120 as a dielectric is formed. The capacitor (C) and the coil (L) formed by the first and second coil patterns 110 and 120 form an LC resonance circuit having a desired resonance frequency (for example, 13.65 MHz). The width w of the first and second coil patterns 110 and 120, the length of the opposing section, and the number of turns of the coil are adjusted.

FIG. 3 shows a configuration example of a typical conventional security tag. 3A is a top view and FIG. 3B is a bottom view.
As shown in FIG. 3, the conventional tag is provided with a thin coil pattern 14 having a large number of turns only on one surface of a dielectric film 24, and a wide width for forming a capacitor at the inner terminal portion of the coil pattern 14. An electrode portion 15a is provided. Then, another electrode portion 15b is provided on the other surface of the dielectric film 24 at a position facing the electrode portion 15a. Thus, the conventional tag is provided with a coil pattern having as many turns as possible on one side, a large electrode pair different from the coil pattern, and a capacitor is formed by this electrode pair and the dielectric film. It was made based on thought. Accordingly, the width of the coil pattern is increased at the terminal portion, and the coil portion is formed thin.

  On the other hand, the tag of this embodiment is configured such that the coil patterns 110 and 120 are provided on both the upper and lower surfaces of the dielectric film 130 as described above, and the dielectric is sandwiched between the coil patterns. And the width w of 120 is increased to provide the functions of the electrode portions 15a and 15b in the prior art. Thereby, it is not necessary to provide the electrode portions 15a and 15b for forming the capacitor in addition to the coil pattern (separately from the portion functioning as a coil), and the width of the coil pattern is substantially uniform as a whole. Furthermore, the coil patterns 110 and 120 can be made shorter (that is, the number of turns) than the conventional configuration.

This principle will be described. Generally, it is known that the Q value representing the performance of a resonant circuit is represented by the following equation.
Q = 2πfL / R
(L is inductance, R is electrical resistance, and f is resonance frequency)

  Here, when the coil patterns 110 and 120 are shortened, the inductance L of the coil decreases. However, by increasing the width w, the electrical resistance R of the coil patterns 110 and 120 also decreases. Therefore, for example, when L and R decrease at the same rate, the value of (L / R) does not change and the Q value also does not change.

  In other words, by reducing the electric resistance R, it is possible to reduce the inductance L (ie, shorten the coil pattern) while maintaining the Q value, and by reducing the electric resistance R, the coil pattern can be reduced. It is possible to suppress the influence on the Q value by shortening.

  For details of the tag having such a characteristic coil pattern, refer to, for example, Japanese Patent Application Laid-Open No. 2001-84463.

  As described above, the security tag according to the present embodiment is arranged such that the pair of coil patterns 110 and 120 provided on the dielectric film 130 have regions facing each other with the dielectric film 130 interposed therebetween, and regions facing each other. The resonance circuit is configured by the capacitor formed by the above and the coil pattern. Therefore, it is not necessary to provide a capacitor forming electrode pattern at the center of the dielectric film 130. However, in order to realize a resonance frequency of a frequency (for example, 13.65 MHz) used in a general electronic merchandise monitoring system, a certain coil length is required, and there is a limit to downsizing the entire tag. Therefore, a region where no coil pattern exists is left in the central portion of the dielectric film 130.

  Therefore, in the security tag of the present embodiment, a region having no coil pattern of the dielectric film 130, specifically, a substantially central region on the upper surface is used, and the resonance unit 150 having a resonance frequency different from that of the resonance circuit is provided. Yes. As will be described later, unlike the resonant circuit that electrically resonates, the resonating unit 150 uses an electromechanical transducer that outputs an electromagnetic wave by mechanical resonance.

FIG. 4 is an exploded perspective view illustrating a configuration example of the resonance unit 150.
The resonance unit 150 includes a magnetostrictive element 152 as an example of an electromechanical transducer, a magnet 151 that applies a DC magnetic field to the magnetostrictive element 152, and a container 153. For example, the container 153 made of a resin material has a storage portion 153a. And the magnetostrictive element 152 which is a sheet-like amorphous magnetic material is accommodated in the accommodating part 153a. The magnet 151 that also functions as a lid of the container 153 is made of a high coercive force material formed in a plate shape. In the casing formed by the magnet 151 and the container 153, the depth of the storage portion is determined so that the magnetostrictive element does not hinder the mechanical displacement indicated by the resonance frequency.

  Such a resonating unit 150 using a magnetostrictive element can control the resonance frequency according to the composition of the magnetostrictive element 152, the heat treatment temperature and time during manufacture, and the strength of the bias magnetic field that the magnet 151 applies to the magnetostrictive element 152. Although possible, it has a resonance frequency on the order of 10 KHz.

  When an alternating magnetic field having a resonance frequency is applied from the outside, the magnetostrictive element 152 causes mechanical resonance and generates a resonance signal. By detecting this resonance signal, the presence of the resonance unit 150 can be detected. The resonance signal can be detected not only by detecting the application and reception of the magnetic field in parallel, but also by intermittently applying the magnetic field and receiving the residual vibration after the application.

  In the present invention, the vibration unit 150 uses an electromechanical transducer having a resonance frequency different from that of the resonance circuit, and as long as the presence can be detected from the outside using the mechanical resonance of the electromechanical transducer, Any configuration may be used. The details of the resonating unit 150 using a magnetostrictive element are known as described in, for example, Japanese Patent Publication No. 62-14873 and Japanese Patent No. 3152862, and thus further description thereof is omitted.

  The electromechanical conversion element is not limited to a magnetostrictive element and can be used in principle as long as it can output an electromagnetic wave that can be detected externally by mechanical resonance. For example, an electrostrictive element may be used. In this case, the lid of the vibrating part 150 will not need to be a magnet.

The tag of the present embodiment may be manufactured by any method, but an example is as follows.
First, the resonant circuit portion is configured as shown in FIG.

  The first and second coil patterns can be composed of a thin film of a conductor such as aluminum or copper. As described above, since the width w of the coil pattern is large and short in the tag of this embodiment, the coil pattern can be generated by punching, which is difficult with a thin pattern such as the conventional configuration shown in FIG. . The first and second coil patterns 110 and 120 can be attached to the surface of the dielectric film 130 with an adhesive or the like. Alternatively, when the dielectric film 130 is a material having a thermal adhesive property such as a polyethylene film, the first and second coil patterns 110 and 120 are heat-bonded to the dielectric film 130 without using an adhesive or the like. be able to.

  Note that the first and second coil patterns 110 and 120 are electrically connected at one end thereof, for example, portions indicated as 115a and 115b in FIG. There is no particular limitation on the method of making the electrical connection. For example, as in the conventional method, the dielectric film 130 is pushed away by pressure and brought into contact with one another, or a needle shape is formed from one coil pattern toward the other coil pattern. A method such as bringing the coil patterns into contact with each other can be used by penetrating the member.

  Finally, the mount 180 is attached with an adhesive or the like as necessary. Although the mount 180 is not essential, for example, when attaching a tag to an article to be monitored, an adhesive and release paper are provided on the back surface (the surface not visible in FIG. 5) of the mount 180, and the release paper is peeled off at the time of application. Thus, the tag can be easily attached to the article.

  And the vibration part 150 is attached to the resonance circuit formed in this way (it functions also as a single-piece | unit). Although there is no particular limitation on how to attach the vibration part 150, the bottom surface of the container 153 can be attached to the upper surface of the dielectric film 130 and the central area (attachment area) where the first coil pattern 110 is not present with an adhesive. . At this time, since the vibration part 150 using the electromechanical transducer has a generally elongated shape, for example, as shown in FIG. 1, it is attached by directing the length direction in the diagonal direction of the tag that is usually rectangular. It is possible to use the area effectively.

  As described in JP-A-2001-84463, instead of the dielectric film 130, a resin or adhesive is applied to the back surface of the coil patterns 110 and / or 120, and the coil patterns are bonded together to resonate. A circuit can also be formed. FIG. 6 is a diagram illustrating the configuration procedure of the resonance circuit portion when such a resonance circuit is employed. The first and second coil patterns 110 and 120 provided with a coating 121 such as a heat-adhesive resin on the back surface are superposed and heat-welded so that the winding directions are different from each other. A coil is electrically connected at the end of the coil pattern to form a resonance circuit.

  In the resonance circuit configured as described above, there is no dielectric film (coating film) other than the portions of the coil patterns 110 and 120, that is, other than the metal thin film portion. Therefore, a mount 180 as a support member that supports the entire resonance circuit is used as a place where the resonance unit 150 is provided. The mount 180 is not necessarily paper, and may be a resin film, a resin sheet, or the like. Moreover, it is preferable that the size of the mount 180 is slightly larger than the outermost periphery of the coil patterns 110 and 120 so as not to unnecessarily increase the size of the tag.

  The resonant circuit can be attached to the mount 180 with an adhesive. Alternatively, in the case where the mount 180 has adhesiveness with the thermal adhesive resin, a coating film of the thermal adhesive resin may be provided on the surface of the resonance circuit that is bonded to the mount 180 and thermally bonded to the mount 180. In this case, the first and second coil patterns 110 and 120 are provided by providing a thermal adhesive resin coating on the lower surface of the first coil pattern 110 and at least the lower surface of the second coil pattern 120. It is possible to heat-weld at once with the mount 180.

  Thereafter, the resonance part 150 is attached to a region on the mount 180 inside the coil pattern, whereby a tag having a configuration as shown in FIG. 1 can be obtained. However, the mount 180 can be seen instead of the dielectric film 130.

  As described above, the tag according to the present embodiment includes the resonance circuit that resonates electrically and the resonance unit that resonates mechanically in the same tag. Therefore, the tag of this embodiment can respond | correspond to the electronic merchandise monitoring system of two different detection principles with one tag.

  Usually, in an electronic merchandise monitoring system using a resonance circuit as a tag, a tag having a resonance frequency of several MHz to several tens of MHz, typically 13.65 MHz, is used, while an electromechanical conversion element is used. In an electronic merchandise monitoring system using a tag, a tag having a resonance frequency of several tens of KHz is used. In this way, since the resonance frequencies of the two are greatly different, in the electronic merchandise monitoring system that detects the resonance circuit, the presence of the resonance part has no effect, and vice versa.

  In addition, in this embodiment, the resonance part is attached using a region where the coil pattern constituting the resonance circuit does not exist. For example, when the resonance unit 150 is attached to a conventional tag as shown in FIG. 3, the resonance unit 150 exists on the coil pattern. In this case, for example, the resonance frequency of the resonance circuit changes due to the influence of the magnetostrictive element (ferromagnetic material) used by the resonance unit 150 as an electromechanical transducer. On the other hand, in this embodiment, since the resonance part 150 does not exist on the coil pattern, there is no or very little influence on the characteristics of the resonance circuit.

  In addition, since the resonance part 150 is attached to the region inside the coil pattern, the size of the tag is not different from the case where the resonance part 150 is not provided. Therefore, the tag constituted only by the resonance circuit can be used as it is, which is advantageous in terms of cost. In addition, when attached to an article to be monitored, a large tag is unpleasant and unfavorable, but it is also advantageous in that respect.

  As described above, according to this embodiment, a highly versatile security tag can be realized with a simple configuration.

It is a top view which shows the structural example of the security tag which concerns on embodiment of this invention. It is a side view which shows the structural example of the security tag which concerns on embodiment of this invention. The structural example of the conventional typical security tag is shown. It is a disassembled perspective view which shows the structural example of the resonance part 150 of the security tag which concerns on embodiment of this invention. It is a figure explaining the manufacturing method of the security tag which concerns on embodiment of this invention. It is a figure explaining another manufacturing method of a security tag concerning an embodiment of the present invention.

Claims (3)

A resonant circuit comprising a dielectric film, and a pair of coil patterns formed on a conductive film having a substantially uniform width, provided on both peripheral edges of the dielectric film;
A security tag having a resonance part using an electromechanical transducer element attached to an area where the coil pattern is not formed on one surface of the dielectric film and having a resonance frequency different from that of the resonance circuit. A resonance circuit having a configuration in which a pair of coil patterns made of a conductive thin film having a substantially uniform width are bonded together by a resin coating;
A support member to which the entire resonant circuit is attached;
A security tag having a resonance part using an electromechanical transducer element attached to a region inside the coil pattern on the support member and having a resonance frequency different from that of the resonance circuit.   The security tag according to claim 1, wherein the electromechanical transducer is a magnetostrictive element.