RFID tag and article management method

Abstract

To provide an RFID tag which prevents unauthorized use by peeling off.SOLUTION: An RFID tag having an IC chip and an antenna for generating power through electromagnetic induction arranged on a substrate is provided, the RFID tag having a variable conductivity member having temperature-dependent conductivity arranged to face at least two adjacently arranged wiring lines of wiring constituting the antenna.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an RFID tag and an article management method. [Background technology]

[0002] An RFID (Radio Frequency Identifier) tag has an inlay such as an IC chip or antenna embedded in a label, and exchanges information by short-range wireless communication with a reader / writer. In a product management system using RFID tags, an RFID tag is attached to each of multiple products, and information on these multiple products can be read all at once using a reader / writer. Patent Document 1 also discloses a device that detects temperature by changing resonance characteristics with temperature changes. In a product management system using RFID tags, it is desirable to be able to prevent fraudulent practices such as, for example, removing the RFID tag from a product and replacing it with a counterfeit product.

[0003] Here, there is a system that allows authenticity of genuine products to be identified by attaching a label indicating authenticity to the genuine product with an adhesive. The base material for such labels is, for example, paper. Even if such an anti-fraud system is implemented, it is conceivable that applying heat to the label makes it easier to peel the label off the product and affix it to another item. Therefore, in order to prevent such fraudulent label removal, slits are sometimes provided in the label. By providing a slit in the label, the label itself can be easily damaged when peeled off from the item, making it possible to prevent the label from being replaced and affixed to a counterfeit product. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-157485 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, in order to prevent an RFID tag from being peeled off from a genuine product and attached to another item, it is conceivable to provide a slit in the RFID tag, as in the label described above. However, because labels use paper or the like as a base material, they are easily damaged when peeled off from an item. However, RFID tags use PET (polyethylene terephthalate) or the like as an inlay material, which is stronger than paper. Therefore, even if a slit is provided in the RFID tag, the RFID tag is not necessarily easily damaged when peeled off from an item. Therefore, providing a slit in the RFID tag does not easily prevent fraudulent use.

[0006] In view of the above-mentioned problems, an object of the present invention is to provide an RFID tag and an article management method that can prevent unauthorized use by peeling off. [Means for solving the problem]

[0007] One aspect of the present invention is an RFID tag that has an IC chip and an antenna that generates power through electromagnetic induction arranged on a substrate, and a conductivity-changing member that changes conductivity depending on temperature arranged opposite at least two or more adjacent wirings that make up the antenna.

[0008] One aspect of the present invention is an item management method that uses an RFID tag having an IC chip and an antenna that generates power through electromagnetic induction arranged on a substrate, and a conductivity-changing member whose conductivity changes in response to temperature arranged opposite at least two or more adjacent wirings that make up the antenna, and attaches the RFID tag to an item so that the conductivity of the conductivity-changing member changes in response to the application of heat from the outside. [Effects of the Invention]

[0009] According to the present invention, the conductivity change member is provided so as to face at least two or more adjacently arranged wires in the antenna, which disables communication of the RFID tag when heated, thereby preventing the RFID tag from being fraudulently removed and attached to another product. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a plan view used to explain an RFID tag according to a first embodiment of the present invention. [Figure 2] 1 is a cross-sectional view used to explain an RFID tag according to a first embodiment of the present invention. [Figure 3] FIG. 1 is an explanatory diagram of an RFID tag according to a first embodiment of the present invention. [Figure 4] FIG. 4 is an explanatory diagram of a modified example of the RFID tag according to the first embodiment of the present invention. [Figure 5] FIG. 4 is an explanatory diagram of a modified example of the RFID tag according to the first embodiment of the present invention. [Figure 6] FIG. 10 is a plan view used to explain an RFID tag according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First Embodiment Fig. 1 is a plan view showing the configuration of an RFID (Radio Frequency Identifier) tag 1 according to a first embodiment of the present invention when viewed from above. Fig. 2 is a cross-sectional view showing the cross section of the RFID tag 1 shown in Fig. 1 taken along the dashed line A.

[0012] The RFID tag 1 has an IC chip 20 and an antenna 30 arranged on one main surface (mounting surface) of a base material 10 made of PET (polyethylene terephthalate) resin or the like. The upper surface of the mounting surface of the RFID tag 1 is covered with a surface material 40 laminated thereon. The surface material 40 can be made of a resin-based material such as PET or transparent PET, or paper. An adhesive layer 50 is provided on the opposite main surface of the RFID tag 1. The adhesive layer 50 is a layer to which an adhesive is applied, and may be, for example, double-sided tape. The RFID tag 1 can be attached to an article such as a commodity by means of the adhesive layer 50. This adhesive layer 50 may be an adhesive layer that uses a hot melt instead of an adhesive.

[0013] The IC chip 20 is an integrated circuit of semiconductor electronic components. Various information about an item is stored in the IC chip 20. For example, the IC chip 20 stores information about the item to which the RFID tag 1 is attached. The IC chip 20 also has the function of executing various controls and data processing for the RFID tag 1.

[0014] The antenna 30 inputs and outputs data to and from an external reader / writer, and generates power through electromagnetic induction. A loop antenna, in which wiring is wound in a spiral shape (which may be a polygonal spiral) on a plane, is used as the antenna 30. The antenna 30 is formed by depositing or etching a metal such as aluminum or copper. Alternatively, the antenna 30 may be formed from conductive ink or conductive paste. The antenna 30 is electrically connected to the IC chip 20 via a power supply line 32.

[0015] Furthermore, in the RFID tag 1 according to the first embodiment of the present invention, the conductivity change member 60 is provided on the main surface of the antenna 30 constituting the loop antenna at a position facing (overlapping) two or more adjacent wirings 31-1 to 31-n when viewed vertically to the main surface. That is, the conductivity change member 60 is provided at a position across at least two of the adjacent wirings 31-1 to 31-n of the antenna 30.

[0016] The conductivity change member 60 is a member that changes to have conductivity when heat is applied until it reaches a certain temperature or higher. That is, the conductivity change member 60 has a large resistance value (for example, infinity) below a reference temperature and is in a non-conductive state. When heat is applied from the outside until it reaches a reference temperature or higher, the conductivity change member 60 transitions to a conductive state (for example, several hundred Ω or less). Furthermore, the conductivity of the conductivity change member 60 is irreversible, and once it becomes conductive, it maintains its conductivity and exhibits almost no change in conductivity even when the temperature drops below the reference temperature. Such a conductivity change member 60 is, for example, a material in which a conductive material is encapsulated in an insulating capsule that melts when heated. When heat is applied from the outside to a temperature above the reference temperature, the capsule melts and the conductive material seeps out from within the capsule. Furthermore, such a conductivity change member may be formed in a planar shape by including multiple capsules containing a conductive material in an insulating substrate.

[0017] As described above, in the RFID tag 1 according to the first embodiment of the present invention, the conductivity change member 60 is provided so as to straddle at least two or more wires 31-1 to 31-n arranged in parallel in the antenna 30. As a result, when the RFID tag 1 is heated, the RFID tag 1 becomes unable to communicate, and it is possible to prevent the RFID tag 1 from being fraudulently removed and attached to another product.

[0018] That is, the RFID tag 1 described above is attached and fixed to an article such as a commodity by the adhesive layer 50. Although a double-sided tape is used as the adhesive layer 50, the adhesive layer 50 may also be an adhesive layer using a hot melt adhesive. When the RFID tag 1 is attached to an article such as a commodity by the adhesive layer 50 in this way, applying heat from the outside to the RFID tag 1 may reduce the adhesiveness of the adhesive layer 50, making it easier to peel. Furthermore, applying heat from the outside to the RFID tag 1 may melt the hot melt of the adhesive layer, making it easier to peel. A hair dryer or the like may be used to apply heat. In this way, it is conceivable that the RFID tag 1 attached to an article (genuine product) may be heated, and the RFID tag 1 may be fraudulently removed and attached to another article (non-genuine product).

[0019] The conductivity change member 60 normally exhibits a large resistance value (before being heated to a temperature equal to or higher than the reference temperature). When the RFID tag 1 is heated, heat is transferred to the conductivity change member 60. When the RFID tag 1 is heated to a temperature equal to or higher than the reference temperature, the resistance value of the conductivity change member 60 decreases, and the conductivity change member 60 transitions to a conductive state. As a result, as shown in FIG. 3 , of the wirings 31-1 to 31-n of the antenna 30, which has a plurality of wirings arranged in parallel, at least two of them are electrically connected (short-circuited) via the conductivity change member 60. In the short-circuited state of the wiring, the antenna 30 cannot generate enough power to communicate with the reader / writer, and the RFID tag 1 cannot communicate with the reader / writer. Furthermore, even if the RFID tag 1 is cooled to a temperature lower than the reference temperature, the conductivity of the conductivity change member 60 is not lost, so the state in which communication with the reader / writer is disabled is maintained.

[0020] As described above, in the first embodiment of the present invention, when the RFID tag 1 is heated with a hair dryer or the like and peeled off from the item, the wiring 31-1 to 31-n of the antenna 30 are short-circuited, and the RFID tag 1 becomes unable to communicate. This makes it possible to make the RFID tag 1 unable to communicate even if the RFID tag 1 is heated with a hair dryer or the like, peeled off from the item, and attached to another product. This makes it possible to know that the RFID tag 1 is not a genuine product because it cannot be read by a reader / writer even if it is attached to an unauthorized product.

[0021] In the above example, the conductivity change member 60 is arranged at one location on the antenna 30 (for example, near one edge of the RFID tag 1 in the longitudinal direction) so as to straddle multiple parallel-arranged wirings 31-1 to 31-n, but the conductivity change member 60 may be arranged at any location as long as it straddles at least two of the parallel-arranged wirings 31-1 to 31-n, and multiple conductivity change members may be arranged.

[0022] The position where the conductivity change member 60 is disposed may be anywhere on the antenna 30. That is, the conductivity change member 60 may be disposed near the feeding point on the antenna 30 from which the feeding line 32 is led out, or may be disposed at a position away from the feeding point. The conductivity change member 60 may be located in the longitudinal direction or in the lateral direction of the antenna 30. The conductivity change member 60 may be located on the inner periphery or on the outer periphery of the antenna 30. The shape of the conductivity change member 60 is arbitrary, and the outer periphery when viewed from above may be either rectangular or round. Furthermore, in the above example, the conductivity change member 60 is arranged in one location on the antenna 30, but as shown in FIG. 4, the conductivity change member 60 may be arranged in multiple locations on the antenna 30, such as a conductivity change member 60a, a conductivity change member 60b, a conductivity change member 60c, and a conductivity change member 60d. 5, the conductivity change member 60 may be disposed so as to cover the entire antenna 30. In short, the conductivity change member 60 may be disposed in any position, number, area, size, or shape as long as it can become conductive due to heat, short-circuit the wiring of the antenna 30, and disable communication.

[0023] <Second embodiment> Next, a second embodiment of the present invention will be described below. Fig. 6 is a plan view showing the configuration of an RFID tag 101 according to the second embodiment of the present invention when viewed from above.

[0024] In this embodiment, the conductivity change member 60 is made of a material that changes to a conductive state and its color when heated. That is, in this embodiment, the conductivity change member 60 exhibits a large resistance value and is a first color (e.g., white) below a reference temperature. When the temperature exceeds the reference temperature, the resistance value of the conductivity change member 60 decreases, the conductivity change member 60 transitions to a conductive state, and the color changes to a second color (e.g., red). Such a substance may be, for example, a conductive material and ink encapsulated in an insulating, heat-melting capsule. When heat is applied from the outside to reach a reference temperature or higher, the capsule melts, and the conductive material and ink ooze from within the capsule. The color that appears when the temperature exceeds the reference temperature can be changed by the color of the ink encapsulated in the capsule. Here, the capsule is opaque and has a color different from the ink encapsulated in it. Such ink may be a conductive ink.

[0025] Normally (before being heated to a temperature equal to or higher than the reference temperature), the conductivity change member 60 is a first color (for example, white). As in the first embodiment, normally, the conductivity change member 60 is an insulator, and even if the conductivity change member 60 is in contact with the antenna, there is no conduction between adjacent wires that make up the antenna, so that electric power can be generated by electromagnetic induction. In contrast, when the RFID tag 101 is heated, as shown in Figure 6, the conductive change member 60 changes to a second color (e.g., red) because the capsule dissolves and the ink comes out of the capsule, making the color of the ink visible from the outside. Furthermore, similarly to the first embodiment, the conductivity change member 60 becomes conductive, and the wiring of the antennas 30 arranged in parallel becomes electrically connected (short-circuited) via the conductivity change member 60. As a result, the antenna 30 is no longer able to generate enough power to communicate with the reader / writer, and the RFID tag 1 becomes unable to communicate with the reader / writer. Furthermore, even if the RFID tag 1 is cooled to a temperature below the reference temperature, the conductivity change member 60 does not lose its conductivity, so the state in which communication with the reader / writer is not possible is maintained, and the RFID tag 1 does not return from the state in which the second color is emitted to the state in which the first color is emitted.

[0026] As described above, in the second embodiment of the present invention, when the RFID tag 101 is heated with a hair dryer or the like and peeled off from the article, the RFID tag 101 becomes unusable and the color of the conductivity change member 60 changes. As a result, even if the RFID tag 101 is heated with a hair dryer or the like, peeled off from the article, and attached to another product, the RFID tag 101 can be rendered unable to communicate, and unauthorized peeling of the RFID tag 101 can be visually detected. As a result, even if the RFID tag 101 is attached to an unauthorized product, it cannot be read by a reader / writer, and it can be determined that the product is not authorized. Furthermore, even without reading with a reader / writer, by visually checking the color of the conductivity change member 60 attached to the RFID tag 101, it can be easily determined whether heat has been applied for the purpose of peeling or the like.

[0027] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention. [Explanation of symbols]

[0028] 10... base material, 20... IC chip, 30... antenna, 31... wiring, 32... power supply line, 40... surface material, 50... adhesive layer, 60... conductive change member

Claims

1. An RFID tag having an IC chip and an antenna that generates power by electromagnetic induction arranged on a substrate, A conductivity change member whose conductivity changes depending on temperature is disposed so as to face at least two or more adjacently disposed wirings among the wirings constituting the antenna. RFID tags like this.

2. The RFID tag according to claim 1 , wherein the conductive change member is disposed at one location on the antenna.

3. The RFID tag according to claim 1 , wherein the conductive change member is arranged at a plurality of different positions on the antenna.

4. The RFID tag according to claim 1 , wherein the conductive change member is disposed so as to cover the entire surface of the antenna.

5. 2. The RFID tag according to claim 1, wherein the conductivity-changing member changes in conductivity and color depending on temperature.

6. An RFID tag is used in which an IC chip and an antenna that generates power by electromagnetic induction are disposed on a substrate, and a conductivity-changing member whose conductivity changes depending on temperature is disposed so as to face at least two or more adjacent wirings of the wirings that constitute the antenna, The RFID tag is attached to an article, and the conductivity of the conductivity-changing member changes in response to the application of heat from the outside. This is an item management method.

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