JP7476531B2 - RFID tags - Google Patents

Description

The present invention relates to an RF tag (RF: Radio Frequency) that can wirelessly read information stored in an IC chip, and further to a technology for preventing unauthorized reading of information stored in an IC chip.

Physical cards have long been used as supplements to magazines. For example, gaming magazines that feature articles on card games often include game cards that can only be obtained in the magazine.

Games that appear in game magazines include not only card games but also online games. Online games are video games that can be played online via a computer network such as the Internet, and online games played on smartphones are currently gaining popularity.

In the case of online games played on smartphones, the supplement to a game magazine is a card that contains information about the supplement that can be obtained by acquiring game items or game characters, encoded in a format that can be read by a smartphone.

Barcodes can be used as a method to encode supplement information onto cards in a way that can be read by smartphones, but with the widespread use of smartphones that support NFC (Near Field Communication), the use of card-type RF tags (RF: Radio Frequency) that can read information wirelessly in game magazine supplements is beginning to be considered.

When RF tags are included as supplements with game magazines, a problem arises in that people browsing the game magazines at book stores can illegally read the supplement information stored in the RF tag. Patent Document 1 discloses an RF tag (non-contact IC medium) with a scratch layer on one side that has radio wave shielding properties and is easily peelable, as an invention related to an RF tag that can prevent unauthorized reading of the information stored in the RF tag.

In the invention disclosed in Patent Document 1, an RF tag with a conductive scratch layer formed on one side cannot communicate wirelessly, preventing unauthorized reading of information using a smartphone. In addition, since the scratch layer formed on one side of the RF tag is easily peelable, the RF tag can communicate wirelessly after the scratch layer is removed from one side, and information can be read from the RF tag using a smartphone.

JP 2014-67140 A

However, the invention disclosed in Patent Document 1 has a problem that when removing the scratch layer from the surface of the RF tag, for example, rubbing the surface on which the scratch layer is formed with a hard metal such as a coin may damage the IC chip built into the RF tag or the connection between the IC chip and the antenna may come loose, causing the RF tag to malfunction. In Patent Document 1 after registration, the scratch layer formed on one side of the RF tag is required to cover 65% or more of the antenna built into the RF tag, and even if the scratch layer is placed to avoid the area where the IC chip is built in, there is a high possibility that the area above the IC chip will be rubbed with a hard metal such as a coin when removing the scratch layer.

The present invention aims to prevent an RF tag from breaking down when removing a scratch layer from the surface of the RF tag, which uses a conductive scratch layer to prevent unauthorized reading of information stored in an IC chip.

The present invention, which solves the above-mentioned problems, is an RF tag in which an inlay is laminated on a base sheet, and an antenna having a coil shape with multiple turns and an antenna end electrically bridged by a jumper wire and an IC chip connected to the antenna are mounted thereon, the inlay has through holes penetrating the base sheet at at least two points on the antenna excluding the connection point between the antenna end and the IC chip, a scratch layer having conductivity and easy peelability is formed on the non-mounting surface of the inlay on which the antenna is not mounted, the scratch layer is electrically connected to the antenna using the through hole on the mounting surface of the inlay on which the antenna is mounted, and is arranged so as to connect the through holes to each other on the non-mounting surface of the inlay, The scratch layer is a layer formed using a conductive ink containing a conductive filler, and is composed of a conductive ink layer that electrically bridges the through hole and the other through hole, and a release ink layer that is formed using a release ink that has releasability to the conductive ink, and gives at least a portion of the conductive ink layer easy peelability, and is characterized in that the release ink layer is formed between the through hole and the other through hole, and the conductive ink layer is formed on top of the release ink layer so as to cross the release ink layer .

In the RF tag according to the present invention, the scratch layer shorts at least two points of the antenna, so that an RF tag with the scratch layer not disconnected does not operate normally, but if at least a part of the scratch layer is removed from the non-mounting surface of the inlay so that the scratch layer is disconnected, the RF tag according to the present invention operates normally. In the RF tag according to the present invention, the scratch layer is formed so as to short at least two points of the antenna, so that the size of the scratch layer can be reduced, and if the scratch layer is disposed away from the location where the IC chip is located, the RF tag according to the present invention can be prevented from breaking down when the scratch layer is removed. Furthermore, in the RF tag according to the present invention, the scratch layer can be disconnected without fail.

In this way, according to the present invention, in an RF tag that uses a conductive scratch layer to prevent unauthorized reading of information stored in an IC chip, it is possible to prevent the RF tag from breaking down when the scratch layer is removed from the surface of the RF tag.

1A and 1B are diagrams illustrating the structure of an RF tag according to an embodiment of the present invention. FIG. 2 is a diagram illustrating the layer structure of the RF tag according to the embodiment. FIG. 1 is a diagram illustrating an inlay to be laminated on an RF tag. A diagram explaining the inlay after forming a scratch layer, etc. FIG. 2 is a diagram illustrating a scratch layer. A diagram explaining a jumper wire. 1A to 1C are diagrams illustrating a manufacturing process of an RF tag.

From here, an embodiment of the present invention will be described. This embodiment is intended to facilitate understanding of the present invention, and the present invention is not limited to this embodiment. Furthermore, unless otherwise specified, the drawings are schematic diagrams drawn to facilitate understanding of the present invention.

Figure 1 is a diagram explaining the structure of the RF tag 1 according to this embodiment, and Figure 2 is a diagram explaining the layer structure of the RF tag 1 according to this embodiment, specifically, a cross-sectional view taken along the line A-A' in Figure 1.

As shown in FIG. 2, the RF tag 1 is configured by laminating, in order from the back surface of the RF tag 1, an inlay 2 in which a coil-shaped antenna 20 having multiple turns and an IC chip 21 connected to the antenna 20 are mounted on the mounting surface of a base sheet 22, an adhesive layer 3 to which adhesive is applied, and a protective sheet 4. In this embodiment, the non-mounting surface of the inlay 2 on which the antenna 20, etc. is not mounted is used as the back surface of the RF tag 1, and FIG. 1 illustrates the back surface of the RF tag 1. Note that the non-mounting surface of the inlay 2 on which the antenna 20, etc. is not mounted can also be used as the front surface of the RF tag 1.

The base sheet 22 of the inlay 2 can be made of plastic materials such as polyethylene terephthalate, polypropylene, or polyethylene, and anisotropic conductive film or anisotropic conductive paste is generally used to connect the antenna 20 and the IC chip 21. In addition to the above-mentioned plastic materials, paper can be used for the protective sheet 4. Furthermore, the adhesive used to form the adhesive layer 3 can be an acrylic adhesive, a rubber adhesive, a silicone adhesive, or the like.

As shown in FIG. 1, a scratch layer 5 that shorts at least two points of the antenna 20 mounted on the mounting surface of the inlay 2 is formed in an easily peelable manner on the non-mounting surface of the inlay 2 used on the back surface of the RF tag 1. In addition, a jumper wire 6 that electrically connects the inner antenna end and the outer antenna end is formed on the non-mounting surface of the inlay 2.

The scratch layer 5 is formed on the non-mounting surface of the inlay 2 to prevent unauthorized use of the RF tag 1. The frequency band used by the RF tag 1 is the HF (High Frequency) band, and in order for the RF tag 1 to operate normally, the parameters of the antenna 20, such as the number of turns, line width and line spacing, are adjusted so that the resonant frequency of the RF tag 1 matches the frequency of the HF band (e.g., 13.56 MHz). If at least two points on the antenna 20 are short-circuited by the scratch layer 5, the parameters of the antenna 20 will change, causing the resonant frequency of the RF tag 1 to change significantly, and the RF tag 1 will not operate normally.

The scratch layer 5, which shorts out at least two points of the antenna 20, is made easily peelable so that at least a portion of the scratch layer 5 can be removed from the non-mounting surface of the inlay 2 to break the scratch layer 5. When at least a portion of the scratch layer 5 is removed from the non-mounting surface of the inlay 2 so that the scratch layer 5 breaks, the portion of the antenna 20 that was shorted by the scratch layer 5 is opened, and the parameters of the antenna 20 return to their design values, allowing the RF tag 1 to operate normally.

As shown in FIG. 1, RF tags 1 compatible with the HF band often use antennas 20 that form a closed circuit by electrically connecting the inner and outer antenna ends. One method of manufacturing the antenna 20 is to use copper wire covered with an insulator, but it is cheaper to manufacture the antenna 20 by printing with conductive ink or etching a base sheet 22 to which metal foil is attached, and manufacturing the antenna 20 by these methods results in the inner and outer antenna ends being open.

Therefore, in this embodiment, a jumper wire 6 that electrically connects the inner antenna end and the outer antenna end to form a closed circuit is provided on the non-mounting surface of the inlay 2. Note that, as a method of electrically connecting the inner antenna end and the outer antenna end to form a closed circuit, a method of forming a bridge circuit that electrically connects the inner antenna end and the outer antenna end via an insulating layer on the mounting surface of the inlay 2 can also be used.

From here, we will provide a detailed explanation of the inlay 2 laminated on the RF tag 1 and the scratch layer 5 formed on the non-mounting surface of the inlay 2.

Figure 3 is a diagram explaining the inlay 2 laminated on the RF tag 1. Figure 3(a) shows the mounting surface of the inlay 2 which forms the antenna 20 etc. Figure 3(b) shows a cross-sectional view taken along line B-B' in Figure 3(a), and Figure 3(c) shows a cross-sectional view taken along line C-C' in Figure 3(a).

As shown in FIG. 3(a), the inlay 2 is configured by mounting a coil-shaped (spiral-shaped) antenna 20 having multiple turns and an IC chip 21 connected to it on the mounting surface of a base sheet 22. The present invention does not limit the number of turns of the antenna 20 mounted on the inlay 2, but in FIG. 3, for ease of understanding, the number of turns of the antenna 20 mounted on the inlay 2 is set to "2."

As shown in FIG. 3(a), at the location of the antenna 20 that is short-circuited by the scratch layer 5, a through hole 23 that penetrates the base sheet 22 of the inlay 2 and a circular land pattern 200 that surrounds the through hole 23 are provided as processing for electrically connecting the antenna 20 mounted on the mounting surface and the scratch layer 5 provided on the non-mounting surface.

In FIG. 3, the number of turns of the antenna 20 mounted on the inlay 2 is set to "2", so one location on the inner circumference and one location on the outer circumference of the antenna 20 are short-circuited by the scratch layer 5, and a through hole 23a and a land pattern 200a are provided at each location.

In the RF tag 1 according to this embodiment, the above-mentioned through-hole 23 and land pattern 200 are also provided at the inner antenna end and the outer antenna end. As shown in FIG. 3(c), a through-hole 23b and a land pattern 200b are provided at each of the inner antenna end and the outer antenna end, but they are not provided in the winding of the antenna 20 between the inner antenna end and the outer antenna end.

Figure 4 is a diagram explaining the inlay 2 after the scratch layer 5 and the like have been formed. The left diagram in Figure 4 shows the front surface of the inlay 2 on which the scratch layer 5 and the like have been formed, and the right diagram in Figure 4 shows the back surface of the inlay 2 on which the scratch layer 5 and the like have been formed. The scratch layer 5 is formed on the non-mounting surface of the inlay 2 when the RF tag 1 is in its state, but in Figure 4, the adhesive layer 3 and protective sheet 4 laminated to the RF tag 1 have been omitted in order to easily explain the inlay 2 after the scratch layer 5 and the like have been formed.

Before forming the scratch layer 5 and the like, the through holes 23 provided in the inlay 2 are filled with conductive ink 230 for conduction. The conductive ink 230 for conduction filled in the through holes 23 provided in the inlay 2 overflows from the through holes 23, and as shown in the left diagram of Fig. 4, a part of the conductive ink 230 for conduction filled in the through holes 23 provided in the inlay 2 is placed on the land pattern 200 surrounding the through holes 23. Also, as shown in the right diagram of Fig. 4, in addition to the scratch layer 5 electrically bridging the through holes 23a and 23a, a jumper wire 6 electrically bridging the through holes 23b and 23b is formed on the back surface of the inlay 2 on which the scratch layer 5 and the like are formed.

Figure 5 is a diagram explaining the scratch layer 5. Figure 5(a) is an enlarged view of the scratch layer 5 in the right diagram of Figure 4. Figure 5(b) is a diagram explaining the layer structure of the scratch layer 5. Specifically, Figure 5(b) is a cross-sectional view taken along line F-F' in the right diagram of Figure 4. Figure 5(c) is a diagram explaining the state of the scratch layer 5 after a portion of the scratch layer 5 has been removed.

As shown in FIG. 1, the scratch layer 5 of this embodiment is formed in a partial area of the non-mounting surface of the inlay 2 laminated on the RF tag 1. As shown in FIG. 5(a), the scratch layer 5 is composed of at least a conductive ink layer 50 that electrically bridges the through hole 23a formed at the location of the antenna 20 to be shorted with the other through hole 23a by connecting the through hole 23a with the other through hole 23a, and a peelable ink layer 51 that gives at least a part of the conductive ink layer 50 easy peelability.

The peelable ink layer 51 is arranged so that the scratch layer 5 that is in the middle of connecting the through hole 23 to the other through hole 23 can be removed. In FIG. 5(b), it is formed between the through hole 23 and the other through hole 23, and the conductive ink layer 50 is formed on the peelable ink layer 51 so as to cross the peelable ink layer 51.

In order to make the through-holes 23 conductive with the conductive ink layer 50 of the scratch layer 5, it is necessary to make the land pattern 200 on the mounting surface of the inlay 2 conductive with the conductive ink layer 50 on the non-mounting surface of the inlay 2, and for this, it is necessary to make the inside of the through-holes 23 conductive. In this embodiment, since the inner walls of the through-holes 23 are not conductive, the inside of the through-holes 23 is made conductive by filling the inside of the through-holes 23 with conductive ink 230 for conductivity. Note that if the inner walls of the through-holes 23 can be made conductive by plating the inner walls, it is not necessary to fill the inside of the through-holes 23 with conductive ink 230 for conductivity.

In FIG. 5(b), the conductive ink 230 for conduction filled inside the through-hole 23 overflows from the through-hole 23. On the mounting surface of the inlay 2, the conductive ink 230 for conduction filled inside the through-hole 23 is conductive to the antenna 20 via the land pattern 200. Also, on the non-mounting surface of the inlay 2, since the conductive ink layer 50 is formed on the through-hole 23, the conductive ink 230 for conduction filled inside the through-hole 23 is conductive to the conductive ink layer 50 constituting the scratch layer 5. Therefore, in the state of FIG. 4(b), the part of the antenna 20 where one through-hole 23 is provided and the part of the antenna 20 where the other through-hole 23 is provided are short-circuited by the conductive ink layer 50 of the scratch layer 5.

In FIG. 5(c), the conductive ink layer 50 on the peelable ink layer 51 is removed by rubbing the conductive ink layer 50 on the peelable ink layer 51. When at least a portion of the conductive ink layer 50 is removed, the portion of the antenna 20 where one through-hole 23 is provided and the portion of the antenna 20 where the other through-hole 23 are provided are opened without being short-circuited by the conductive ink layer 50. When the portion of the antenna 20 where one through-hole 23 is provided and the portion of the antenna 20 where the other through-hole 23 is provided are opened, the parameters of the antenna 20 return to the design values, and the RF tag 1 operates normally.

The conductive ink layer 50 may have any shape as long as it can electrically connect the part of the antenna 20 where one through-hole 23 is provided and the part of the antenna 20 where the other through-hole 23 is provided. In FIG. 5(a), the conductive ink layer 50 has a rectangular shape, but the conductive ink layer 50 can also have, for example, a gourd shape in which the conductive ink layer 50 on the peelable ink layer 51 is narrow.

In this way, in the RF tag 1 according to this embodiment, the scratch layer 5 is formed so that the part of the antenna 20 where one through hole 23 is provided and the part of the antenna 20 where the other through hole 23 is provided can be electrically connected. This makes it possible to reduce the area in which the scratch layer 5 is formed, and reduces the possibility that the back surface of the RF tag 1 above the IC chip 21 will be rubbed against a hard metal such as a coin when removing the scratch layer 5.

If the scratch layer 5 is formed near the IC chip 21, when the scratch layer 5 is removed, the back surface of the RF tag 1 above the IC chip 21 may be rubbed with a hard metal such as a coin, causing damage to the RF tag 1. Therefore, it is desirable to provide the scratch layer 5 away from the IC chip 21. In FIG. 1, in order to provide the scratch layer 5 away from the IC chip 21, the IC chip 21 is placed below the center line of the height of the RF tag 1, and the location to be short-circuited by the scratch layer 5 is placed above the center line of the height of the RF tag 1.

In addition, if the inner antenna end and the outer antenna end are short-circuited using a scratch layer 5 instead of a jumper wire 6, the RF tag 1 will function normally even if the scratch layer 5 is formed, so the parts of the antenna 20 that are short-circuited by the scratch layer 5 will be parts other than the antenna ends.

Figure 6 is a diagram explaining the jumper wire 6. Figure 6(a) is an enlarged view of the jumper wire 6 in the right diagram of Figure 4. Figure 6(b) is a diagram explaining the configuration of the jumper wire 6, specifically, Figure 6(b) is a cross-sectional view of G-G' in the right diagram of Figure 4.

As shown in Fig. 6(a), the jumper wire 6 electrically bridges the inner and outer antenna ends. As in Fig. 5(b), the conductive ink 230 filled inside the through-hole 23 overflows from the through-hole 23, and as explained with reference to Fig. 5(b), in the state of Fig. 6(b), the inner and outer antenna ends are conductive via the jumper wire 6, and the antenna 20 forms a closed circuit.

From here, the manufacturing process of the RF tag 1 explained so far will be explained. Figure 7 is a diagram explaining the manufacturing process of the RF tag 1. When manufacturing the RF tag 1 explained so far, an inlay 2 mounting an antenna 20 and an IC chip 21 is manufactured. As described above, the antenna 20 formed on the mounting surface of the inlay 2 can be manufactured by printing using conductive ink or etching a base sheet 22 to which metal foil is attached.

Next, a through hole 23 is processed in the inlay 2 on which the antenna 20 and IC chip 21 are mounted. The through hole 23 can be formed by punching using a mold.

Next, the through-holes 23 machined in the inlay 2 are filled with conductive ink 230 for electrical continuity. As shown in FIG. 5(b), the conductive ink 230 for electrical continuity is filled into the through-holes 23 so that it overflows from the through-holes 23. The conductive ink used in the manufacture of the RF tag 1 refers to a paste-like ink containing conductive fillers, such as gold powder, silver powder, copper powder, and conductive carbon, dispersed in a vehicle.

Next, an adhesive layer 3 is laminated on the mounting surface of the inlay 2 after filling the through-hole 23 with conductive ink 230 for electrical continuity, and a protective sheet 4 is further laminated on top of the adhesive layer 3 to produce an RF tag 1 that does not have a scratch layer 5 or the like.

Next, the jumper wire 6 shown in FIG. 6 is formed on the back surface of the RF tag 1 where the scratch layer 5 and the like are not formed. The jumper wires included in the jumper wire 6 can be formed by screen printing.

Next, the scratch layer 5 shown in FIG. 5 is formed on the non-mounting surface of the inlay 2 on the back surface of the RF tag 1 where the scratch layer 5 etc. is not formed, and the RF tag 1 shown in FIG. 1 is manufactured. Screen printing can be used to form the scratch layer 5, and the scratch layer 5 is formed in the order of the peelable ink layer 51 and the conductive ink layer 50. The peelable ink used to form the peelable ink layer 51 can be an ink that has good peelability against conductive ink, and for example, ethylene-based wax can be used as the peelable ink.

The RF tag 1 described so far can be modified in various ways without departing from the spirit of the present invention. In this embodiment, the number of turns of the antenna 20 mounted on the inlay 2 is "2", but the number of turns of the antenna 20 mounted on the inlay 2 is not limited to "2" and may be more than this. When using an antenna 20 with more than "2" turns, the number of places on the antenna 20 that are short-circuited can be two or more. Also, the shape of the RF tag 1 described so far is credit card shaped, but the shape of the RF tag 1 can also be circular.

REFERENCE SIGNS LIST 1 RF tag 2 Inlay 20 Antenna 200 Land pattern 21 IC chip 22 Base sheet 23 Through hole 230 Conductive ink for electrical continuity 3 Adhesive layer 4 Protective sheet 5 Scratch layer 6 Jumper wire

Claims (1)

An RF tag comprising an inlay laminated on a base sheet, the inlay having an antenna in the form of a coil having a number of turns, the antenna end of which is electrically bridged by a jumper wire, and an IC chip connected to the antenna, the inlay having through-holes penetrating the base sheet at at least two points of the antenna excluding the connection point between the antenna end and the IC chip, a scratch layer having electrical conductivity and easy peelability formed on the non-mounting surface of the inlay on which the antenna is not mounted, the scratch layer being electrically connected to the antenna by using the through-hole on the mounting surface of the inlay on which the antenna is mounted, and being arranged so as to connect the through-holes to each other on the non-mounting surface of the inlay ,
The scratch layer is a layer formed using a conductive ink containing a conductive filler, and is composed of a conductive ink layer that electrically bridges the through hole and the other through hole, and a release ink layer that is formed using a release ink that has releasability to the conductive ink and gives at least a portion of the conductive ink layer easy peelability, and the release ink layer is formed between the through hole and the other through hole, and the conductive ink layer is formed on top of the release ink layer so as to cross the release ink layer .

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