JP4089167B2 - RFID tag - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an RFID tag using RFID (Radio Frequency Identification) technology.
[0002]
[Prior art]
Conventionally, an antenna coil in which a coil body is spirally wound around the axis of the magnetic core member around a magnetic core member formed in a rod shape with ferrite or the like, and an antenna coil that is electrically connected to the coil body of the antenna coil and managed There is known a tag including an IC chip in which information related to the article is stored. This tag is coated with a special exterior material that protects against atmospheric forces, dust, and external forces caused by contact with surrounding objects, and is attached to a planar portion of the article to be identified or monitored. The tag attached to the flat portion of the article in this way is adapted to identify or monitor the article by reading information stored in the IC chip or by resonating with a radio wave of a specific frequency. Composed.
[0003]
[Problems to be solved by the invention]
However, conventional exterior materials are generally composed of a container that accommodates a tag and a lid that seals the container, and it is difficult to reliably ensure sealing at the joint between the container and the lid. When the sealing property is not secured, there is a problem that the tag cannot be effectively protected from atmospheric humidity and dust. In addition, in the case of a tag attached to an article that is frequently moved, it is necessary to avoid the tag from projecting greatly from the article to be managed and avoid contacting the tag with surrounding objects when carrying the article. There is also. Furthermore, since the conventional tag uses a magnetic core member made of ferrite or the like, the tag itself cannot be bent. However, in recent years, a tag is often attached to the curved outer surface of a disk-shaped article or the curved outer surface of a cylindrical pipe, and the tag itself is made flexible so that the tag is curved. It is convenient if it can be curved according to the outer surface and attached directly to the article in that state.
[0004]
A first object of the present invention is to provide an RFID tag capable of reliably ensuring the sealing between an IC chip and an antenna coil.
A second object of the present invention is to provide an RFID tag that can be formed so as to be extremely thin and prevent a tag attached to the article from coming into contact with surrounding objects during the conveyance of the article.
A third object of the present invention is to provide an RFID tag that can be curved in accordance with the curved outer surface of an article.
[0005]
[Means for Solving the Problems]
As shown in FIGS. 1 and 2, the invention according to claim 1 is an IC chip 13 that is attached to an article 11 and stores unique information that is different for each article 11, and is attached to the article 11 and the IC chip 13. The RFID tag is provided with an antenna coil 14 electrically connected to the antenna.
Its characteristic configuration is, IC chip 13 and the antenna coil 14 is surrounded integrally with the resin 16 by injection molding or cast molding, the synthetic polymer polyamide resin 16 is flexible, made of urethane or silicone, The antenna coil 14 includes a magnetic core member 14a formed of a magnetic material in a flat plate shape and a coil body 14b. The magnetic core member 14a is formed of a composite material of powder or flakes and plastic made of a magnetic material. It consists of ~ 56% by volume magnetic material and 90 ~ 44% by volume plastic .
In the RFID tag according to the first aspect, since the IC chip 13 and the antenna coil 14 are surely surrounded and sealed by the resin, the IC chip 13 and the antenna coil 14 are reliably isolated from the outside air, Effective protection from humidity and dust.
Here, when the resin 16 is injection-molded, the productivity of the RFID tag can be improved. However, if the IC chip 13 and the antenna coil 14 are relatively fragile, the resin chip 16 surrounds the IC chip 13 and the antenna coil 14 by casting to avoid damage due to pressure during injection molding. It is preferable to do.
[0006]
The invention according to claim 2 is the invention according to claim 1, the coil main body 14b is formed by winding spirally about an axis extending in the plane of the magnetic core member 14a to the magnetic core member 14a The IC chip 13 is an RFID tag attached to the surface of the magnetic core member 14a or provided in the vicinity of the magnetic core member 14a.
In the RFID tag according to the second aspect, when the radio wave is transmitted toward the tag 12, the tag 12 resonates and the IC chip 13 is activated, so that the unique information stored in the IC chip 13 is stored. Retransmitted from the antenna coil 14. Further, since the antenna coil 14 can be formed very thin, the protruding amount from the surface of the attached article 11 is reduced because the tag 12 itself is thin, and the tag 12 comes into contact with surrounding objects while the article 11 is being transported. Can be prevented.
[0007]
The invention according to claim 3 is the invention according to claim 1, and as shown in FIGS. 5 and 6, the coil body 64b is flush with the magnetic core member 64a so as to surround the outer peripheral edge of the magnetic core member 64a. The RFID tag is configured by being wound in a spiral shape and having the IC chip 13 bonded to the surface of the magnetic core member 64a.
In the RFID tag according to the third aspect, the antenna coil 64 can be formed thinner, and the tag 62 itself can be further thinned. When radio waves are transmitted toward the tag 62, even if the distance between the radio wave transmission source and the antenna coil 64 is relatively large, the magnetic flux density passing through the center of the coil body 64b by the magnetic core member 64a (this magnetic flux is Generated by radio waves). As a result, the resonance amplitude of the resonance circuit including the antenna coil 64 is increased, so that the tag 62 can be sufficiently activated, and unique information stored in the IC chip 13 is retransmitted from the antenna coil 64.
[0008]
Further, the magnetic core member 14a, 64a is formed by a composite material of a powder or flakes and plastic made of a magnetic material, so that the composite material consists of 10-56% by volume of the magnetic material and 90 to 44% by volume of the plastic, the By blending the magnetic material and the plastic at a ratio, the flexible magnetic core members 14a and 64a can be obtained, the RFID tag itself can be curved, and the attached portion of the article 11 is a curved surface. Also, the tag can be attached in a curved state.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, an RFID tag 12 is attached to the surface of the article 11. The tag 12 includes an IC chip 13 in which unique information different for each article 11 is stored, and an antenna coil 14 electrically connected to the IC chip 13. In this embodiment, the article 11 is a repair part stored in a warehouse, and is formed of a nonmagnetic and nonconductive material such as plastic. The antenna coil 14 includes a magnetic core member 14a formed of a magnetic material in a flat plate shape, and a coil body 14b wound around the magnetic core member 14a in a spiral shape around an axis extending in the plane of the magnetic core member 14a. Have.
[0010]
The magnetic core member 14a is formed in a rectangular plate shape by a composite of powder or flakes and plastic made of a magnetic material, or Fe-based (METGLAS2605S-2 manufactured by Allied Chemical) or Co-based (manufactured by Allied Chemical). It is formed in a rectangular plate shape by a laminated material of amorphous foil such as METGLAS 2714A). Examples of the magnetic material include soft magnetic ferrite or soft magnetic metal. As the plastic, a thermoplastic plastic having good processability or a thermosetting plastic having good heat resistance can be used. Examples of the powder made of the magnetic material include carbonyl iron powder, atomized powder such as iron-permalloy, and reduced iron powder. On the other hand, flakes made of a magnetic material include flakes obtained by refining the above powder with a ball mill or the like to form a powder, and then mechanically flattening the powder, or molten particles of an iron-based or cobalt-based amorphous alloy. Flakes obtained by impinging on water-cooled copper are used.
[0011]
When the magnetic core member 14a is formed of a composite material, the magnetic core member 14a includes 10 to 56% by volume of a magnetic material and 90% to 44% by volume of the magnetic core member 14a in order to give the magnetic core member 14a flexibility. It is preferably formed of a composite material made of plastic. When the powder or flake made of a magnetic material is less than 10 volumes, the magnetic permeability of the obtained magnetic core member 14a is lowered, and in order to obtain the required magnetic permeability, it is necessary to make the magnetic core member 14a itself large. The antenna coil 14 itself cannot be downsized. On the other hand, the magnetic core member 14a obtained when the powder or flakes made of a magnetic material is 56% by volume or more may not have flexibility. A particularly preferable range of the powder or flake made of the magnetic material is 25% to 45% by volume.
[0012]
When the magnetic core member 14a is formed from a composite material, it is preferable to form the magnetic core member 14a by injection molding or compression molding the composite material. However, when the tag 12 needs to be particularly thin, the magnetic core member 14a is applied to the film or sheet and the film or sheet by applying and drying the composite material on the flexible film or sheet. You may form with the coating film which consists of another composite material. The magnetic core member 14a formed in this way is flexible compared to a magnetic core member formed of fragile ferrite, so it is difficult to break even if it is thin. Further, since the powder or flakes made of a magnetic material are dispersed in the plastic, that is, the magnetic powder or flakes are insulated from each other by the plastic, the entire magnetic core member 14a does not have electrical conductivity, and high frequency radio waves. Does not generate eddy current.
The coil body 14b is a copper wire, and is wound around the magnetic core member 14a in a spiral shape around the axis of the magnetic core member 14a. The 1C chip 13 is electrically connected to the copper wire of the antenna coil 14.
[0013]
As shown in FIG. 4, the IC chip 13 is connected to the power supply circuit 13a, the radio frequency (RF) circuit 13b, the modulation circuit 13c, the demodulation circuit 13d, the CPU 13e, and the CPU 13e. And a memory 13f to be stored. The power supply circuit 13 a includes a capacitor (not shown), and this capacitor forms a resonance circuit together with the antenna coil 14. This capacitor is charged with electric power generated by the mutual induction when the antenna coil 14 receives radio waves of a specific frequency (frequency at which the resonance circuit resonates). The power supply circuit 13a rectifies and stabilizes this power, supplies it to the CPU 13e, and activates the IC chip 13. The memory 13f includes a ROM (read only memory), a RAM (ramdom-access memory), and an EEPROM (electrically erasable programmable read only memory), and responds to a read command by radio wave data communication from the identification means 17 under the control of the CPU 13e. The stored data is read out, and data is written in response to a write command from the identification means 17.
[0014]
Returning to FIGS. 1 and 2, the IC chip 13 is bonded to the surface of the magnetic core member 14a while being electrically connected to the copper wire of the antenna coil 14, and the IC chip 13 and the antenna coil 14 are formed by casting. The resin 16 is integrally surrounded. Cast molding in this embodiment is performed using a mold 21 that can be divided into two parts as shown in FIG. 3A, and the upper mold 22 in which the resin injection port 22a is formed is removed by a small screw 26. It is attached to the lower mold 23 as possible. Inside the upper mold 22 and the lower mold 23, pins 22b and 23b are formed to float and support the magnetic core member 14a having the IC chip 13 bonded to the surface thereof in the center. When the resin is actually cast, as shown in FIG. 3B, the magnetic core member 14a having the IC chip 13 bonded to the surface thereof is floated and supported inside the mold 21 by its pins 22b and 23b. In this state, resin is injected from the injection hole 22a and molded. Examples of the resin to be injected include polypropylene (PP), polyethylene terephthalate (PET), polyethylene (PE), synthetic polymer polyamide (trade name “nylon”), urethane, silicone, and the like.
[0015]
After the resin injected into the mold 21 is cured, the upper mold 22 is removed from the lower mold 23, and the resin molded product 24 is taken out from the lower mold 23 as shown in FIG. In this resin molded product 24, the IC chip 13 and the antenna coil 14 are integrally surrounded by the resin, and small holes 24a corresponding to the pins 22b and 23b supporting the magnetic core member 14a are formed. The small hole 24a is sealed with resin as necessary, and the RFID tag 12 of the present invention shown in FIG. 3D in which the IC chip 13 and the antenna coil 14 are integrally surrounded by the resin 16 is obtained. Further, the small hole 24a may be closed by covering with an exterior seal (not shown) covering the upper surface or a double-sided adhesive tape described later.
[0016]
In the RFID tag 12 configured as described above, the IC chip 13 and the antenna coil 14 are surely surrounded and sealed by the resin, so that the IC chip 13 and the antenna coil 14 are reliably isolated from the outside air, Can be effectively protected from humidity and dust.
The RFID tag 12 of the present invention is attached to the surface of the article 11 via an adhesive or double-sided adhesive tape (not shown) and used to manage the article 11. Since the RFID tag 12 in this embodiment uses the antenna coil 14 formed of a coil body 14b spirally wound around a magnetic core member 14a formed in a flat plate shape, the thickness thereof is relatively thin. Since it can be formed, it is possible to prevent the tag 12 from significantly protruding from the article 11 when the tag 12 is attached to the article 11. As a result, the tag 12 can be prevented from coming into contact with surrounding objects when the article 11 is conveyed.
[0017]
Further, since the magnetic core member 14a in this embodiment is formed of a composite material so as to have flexibility, the resin 16 surrounding the IC chip 13 and the antenna coil 14 is a flexible synthetic polymer polyamide. (Trade name “nylon”), urethane, silicone, etc., the RFID tag 12 itself is flexible, even if the outer surface to which the tag 12 is attached is curved. Can be curved in accordance with the outer surface of the article 11, and the tag 12 can be attached to the outer surface of the article 11 in such a manner.
[0018]
The article 11 to which the RFID tag 12 is attached in this way is managed using a handy type identification means 17 that can be carried by the manager. Specifically, as shown in FIG. 4, the transmission / reception antenna 17 a of the identification unit 17 is brought close to the tag 12, and a question signal is transmitted from the transmission / reception antenna 17 a toward the antenna coil 14 of the tag 12 by radio waves of a specific frequency. The transmitted radio wave of the interrogation signal is received by the antenna coil 14 of the tag 12. The CPU 13e of the IC chip 13 electrically connected to the antenna coil 14 transmits information on the article 11 written in the memory 13f based on the inquiry signal. The transmitted data is received by the transmission / reception antenna 17a of the identification means 17, and information unique to the article 11 is displayed on the display unit 17b of the identification means 17. The administrator manages the article 11 by looking at the information displayed on the display unit 17b.
[0019]
In the above-described embodiment, the example in which the tag 12 is attached to the article 11 formed of a non-magnetic and non-conductive material such as plastic is shown. However, the attached portion of the article 11 to which the tag 12 is attached is a metal. In this case, it is preferable to interpose a conductive plate made of a conductive material between the tag 12 and the metal part to which the tag 12 is attached. In this case, the thickness of the conductive plate is 0.01 to 2 mm, preferably 0.05 to 0.5 mm. When the RFID tag 12 is attached to the metal part of the article via the conductive plate and radio waves are transmitted from the transmitting / receiving antenna 17a of the identification means 17 toward the antenna coil 14 of the tag 12, the conductive plate prevents the radio waves from passing through the article 11. Since shielding is performed, no eddy current is generated in the metal portion of the article 11. As a result, since the tag 12 resonates, the IC chip 13 is activated, and unique information stored in the IC chip 13 is retransmitted from the antenna coil 14. As a result, the identification means 17 can reliably read the information stored in the memory of the IC chip 13.
[0020]
In the above-described embodiment, the example in which the IC chip 13 is bonded to the surface of the magnetic core member 14a is shown. However, as long as the IC chip 13 and the antenna coil 14 are integrally surrounded by the resin 16, the IC chip is used. 13 may be provided in the vicinity of the magnetic core member 14a without being bonded to the magnetic core member 14a.
Further, in the above-described embodiment, the IC chip 13 and the antenna coil 14 are surrounded by the resin 16 by the casting, but the strength of the IC chip 13 and the antenna coil 14 is relatively high and can sufficiently withstand the pressure by the injection molding. In this case, the IC chip 13 and the antenna coil 14 may be surrounded by the resin 16 by injection molding. When the resin 16 is molded by injection molding, it is possible to improve the productivity of the RFID tag as compared with the case of performing casting molding.
[0021]
5 and 6 show a second embodiment of the present invention. 5 and 6, the same reference numerals as those in FIGS. 1 and 2 denote the same components.
In this embodiment, the article 11 is formed of a non-magnetic and non-conductive material such as plastic, and the antenna coil 64 is a magnetic core member 64a formed of a magnetic material in a flat plate shape, and the outer peripheral edge of the magnetic core member 64a. And a coil body 64b wound spirally on the same plane as the magnetic core member 64a. The magnetic core member 64a is formed in a disk shape by a metal or ferrite powder or a composite material of flakes and plastic, or Fe-based (METGLAS 2605S-2 manufactured by Allied Chemical Co.) or Co-based (manufactured by Allied Chemical Co., Ltd.). It is formed in a disk shape by a laminated material of amorphous foil such as METGLAS 2714A).
[0022]
The coil body 64b is formed by etching a copper foil or an aluminum foil bonded to the surface of the resin film 64c, and the magnetic core member 64a is bonded to the resin film 64c so as to be positioned at the center of the coil body 64b. When the magnetic core member 64a is formed of a composite material, a method of injection molding or compression molding the composite material into a disk shape before bonding to the resin film 64c, and a liquid composite material to the coil body 64b. There is a method of pouring and solidifying. The IC chip 13 is bonded to the surface of the magnetic core member 64a, and the IC chip 13 and the antenna coil 64 are integrally surrounded by resin by injection molding or cast molding. The configuration other than the above is the same as that of the first embodiment.
[0023]
The RFID tag 62 configured in this manner is attached to the article 11 via an adhesive or a double-sided adhesive tape, but the antenna coil 64 is a coil body 64b wound in a spiral on the same plane as the magnetic core member 64a. It will be extremely thin. For this reason, the tag 62 is also very thin, and protrudes very slightly from the article 11, so that the mounting strength can be sufficiently secured. When a radio wave is transmitted from the transmission / reception antenna of the identification unit toward the antenna coil 64 of the tag 62, the center of the coil main body 64b is obtained due to the presence of the magnetic core member 64a even if the distance between the transmission / reception antenna and the antenna coil 64 is relatively large. The magnetic flux density passing through (this magnetic flux is generated by the radio wave) increases. As a result, since the tag 62 resonates, the IC chip 13 is activated, and unique information stored in the IC chip 13 is retransmitted from the antenna coil 64 toward the transmission / reception antenna. As a result, the identification means can read the information stored in the memory of the IC chip 13.
[0024]
【The invention's effect】
As described above, according to the present invention, the IC chip and the antenna coil are integrally surrounded by the resin by injection molding or casting, and the IC chip and the antenna coil are sealed by the resin. The antenna coil is reliably isolated from the outside air and can be effectively protected from atmospheric humidity and dust. In this case, an antenna coil is constituted by a magnetic core member formed in a flat plate shape by a magnetic material, and a coil body wound spirally around an axis extending in the plane of the magnetic core member around the magnetic core member, If the IC chip is adhered to the surface of the magnetic core member or provided in the vicinity of the magnetic core member, the antenna coil can be formed extremely thin and the tag itself can be thinned.
[0025]
Further, an antenna coil is constituted by a magnetic core member formed in a flat plate shape with a magnetic material and a coil body wound spirally on the same plane as the magnetic core member so as to surround the outer peripheral edge of the magnetic core member, If the IC chip is bonded to the surface of the magnetic core member, the antenna coil can be made thinner. As a result, the protruding amount of the RFID tag from the surface of the article can be reduced, and the tag can be prevented from coming into contact with surrounding objects during the conveyance of the article.
Further, if the magnetic core member is formed of a composite material of powder or flakes and plastic made of a magnetic material, and the composite material is blended with 10 to 56% by volume of magnetic material and 90 to 44% by volume of plastic, flexibility can be obtained. A magnetic core member having a property can be obtained, the RFID tag itself can be curved, and the tag can be attached in a curved state even if the attached portion of the article is a curved surface.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view taken along line AA of FIG. 2 showing an RFID tag according to a first embodiment of the present invention.
2 is a cross-sectional view taken along the line BB in FIG. 1 showing the configuration of the tag.
FIG. 3 is a view showing a manufacturing process for obtaining the tag by casting.
FIG. 4 is a configuration diagram showing a state in which a transmission / reception antenna of an identification unit is opposed to the tag.
FIG. 5 is a cross-sectional view taken along line EE of FIG. 6 showing a second embodiment of the present invention.
6 is a cross-sectional view taken along the line FF of FIG. 5 showing the configuration of the tag. .
[Explanation of symbols]
11 Article 12, 62 RFID tag 13 IC chip 14, 64 Antenna coils 14a, 64a Magnetic core members 14b, 64b Coil body 16 Resin

Claims (3)

An IC chip (13) attached to the article (11) and storing unique information different for each article (11), and attached to the article (11) and electrically connected to the IC chip (13) RFID tag provided with the antenna coil (14, 64),
The IC chip (13) and the antenna coil (14, 64) are integrally surrounded by a resin (16) by injection molding or casting ,
The resin (16) is made of a synthetic polymer polyamide having flexibility, urethane or silicone,
The antenna coil ( 14, 64) has a magnetic core member (14a, 64a) and a coil body (14b, 64b) formed of a magnetic material in a flat plate shape ,
The magnetic core member (14a, 64a) is formed of a composite material of powder or flakes and plastic made of a magnetic material,
The RFID tag, wherein the composite material is made of 10 to 56% by volume of a magnetic material and 90 to 44% by volume of a plastic . The coil body (14b) is configured to be wound spirally around the axis extending in the plane of the magnetic core member (14a) around the magnetic core member (14a) ,
The RFID tag according to claim 1, wherein an IC chip (13) is adhered to the surface of the magnetic core member (14a) or provided in the vicinity of the magnetic core member (14a). The coil body (64b) is configured to be spirally wound on the same plane as the magnetic core member (64a) so as to surround the outer peripheral edge of the magnetic core member (64a) ,
The RFID tag according to claim 1, wherein an IC chip (13) is bonded to a surface of the magnetic core member (64a).

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