JP6465260B1 - Metal ring with RFID tag and method of attaching RFID tag - Google Patents

Abstract

Provided is a metal ring with an RFID tag, which allows a metal ring to function more reliably as a radiating element. A metal ring with an RFID tag according to the present invention includes a metal ring, an RFID tag having a UHF band RFIC element and a loop electrode connected to the RFIC element, and the RFID tag includes a loop electrode. The loop surface is provided along the circumferential direction of the metal ring, the loop electrode and the metal ring are coupled via a magnetic field, and the metal ring functions as a radiating element.

Description

  The present invention relates to a metal ring with an RFID tag (Radio Frequency Identification) and a method for attaching the RFID tag.

  Conventionally, an article with an RFID tag (electromagnetic coupling module) configured to use a metal surface of the article as a radiator is known (see, for example, Patent Document 1).

International Publication No. 2007/125683

  In Patent Document 1, it is assumed that an article to which an RFID tag is attached has a flat surface facing the entire attachment surface of the RFID tag. For this reason, when the article to which the RFID tag is attached is a metal ring that does not have a flat surface facing the entire attachment surface of the RFID tag, the technique of Patent Document 1 functions more reliably as a radiation element. I can't let you.

  An object of the present invention is to provide a metal ring with an RFID tag and a method for attaching the RFID tag that can make the metal ring function more reliably as a radiating element.

A metal ring with an RFID tag according to an aspect of the present invention includes a metal ring,
An RFID tag having a UHF band RFIC element and a loop electrode connected to the RFIC element;
With
The RFID tag is provided such that a loop surface of the loop electrode extends along a circumferential direction of the metal ring, the loop electrode and the metal ring are coupled via a magnetic field, and the metal ring Is configured to function as a radiating element.

An RFID tag mounting method according to an aspect of the present invention is a method of mounting a block-shaped RFID tag having a UHF band RFIC element and a loop-shaped electrode connected to the RFIC element to a metal wire.
The RFID tag is supported on an adhesive layer of an insulating sheet, and the insulating sheet is wound so as to cover the RFID tag and the metal wire with the adhesive layer inside.

  According to the present invention, the metal ring can function more reliably as a radiating element.

It is sectional drawing which shows schematic structure of the metal ring with an RFID tag which concerns on Embodiment 1 of this invention. FIG. 2 is a cross-sectional view taken along line A1-A1 of FIG. It is an expanded sectional view of FIG. It is sectional drawing which shows the principle of operation in which a metal ring functions as a radiating element. It is sectional drawing which shows the magnetic field radiated | emitted from metal rings. It is sectional drawing which shows schematic structure of the metal ring with a RFID tag in which the some RFID tag was attached with respect to one metal ring. It is sectional drawing which shows the modification which wound the insulating sheet around only the attachment part of the RFID tag of metal rings. It is a perspective view showing a modification of a RFID tag partially transparently. It is a perspective view showing a modification of a RFID tag partially transparently. It is a perspective view showing a modification of a RFID tag partially transparently. It is sectional drawing which shows an example of the attachment method of the RFID tag which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the attachment process following FIG. 9A. It is a perspective view which shows schematic structure of the article | item management system using the metal ring with an RFID tag of FIG. It is sectional drawing which shows schematic structure of a cable antenna and an auxiliary antenna. It is a figure which shows the equivalent circuit of a matching circuit part. It is an expanded sectional view which shows schematic structure of the metal ring with a RFID tag which concerns on Embodiment 2 of this invention. It is sectional drawing which shows an example of the attachment method of the RFID tag which concerns on Embodiment 2 of this invention. It is sectional drawing which shows the attachment process following FIG. 14A.

A metal ring with an RFID tag according to an aspect of the present invention includes a metal ring,
An RFID tag having a UHF band RFIC element and a loop electrode connected to the RFIC element;
With
The RFID tag is provided such that a loop surface of the loop electrode extends along a circumferential direction of the metal ring, the loop electrode and the metal ring are coupled via a magnetic field, and the metal ring Is configured to function as a radiating element.

  According to this configuration, by providing the RFID tag so that the loop surface of the loop electrode is along the circumferential direction of the metal ring, the loop electrode and the metal ring are coupled via a magnetic field, and the metal The ring can function more reliably as a radiating element.

  The loop surface of the loop electrode has a longitudinal direction and a lateral direction, and the RFID tag may be provided so that the longitudinal direction of the loop surface is along the circumferential direction of the metal ring. Good. According to this configuration, the degree of coupling between the loop electrode and the metal ring can be improved, and the metal ring can function more reliably as a radiating element.

  The insulating sheet may further include an adhesive layer, and the insulating sheet may be wound so as to cover the RFID tag and the metal ring with the adhesive layer inside. According to this configuration, the RFID tag can be easily and firmly attached to the metal ring by the insulating sheet.

  Moreover, you may further provide the buffer member which fills the clearance gap between the said RFID tag, the said metal ring, and the said adhesion layer. According to this configuration, the strength of the metal ring with the RFID tag can be improved.

An RFID tag mounting method according to an aspect of the present invention is a method of mounting a block-shaped RFID tag having a UHF band RFIC element and a loop-shaped electrode connected to the RFIC element to a metal wire.
The RFID tag is supported on an adhesive layer of an insulating sheet, and the insulating sheet is wound so as to cover the RFID tag and the metal wire with the adhesive layer inside.

  According to this method, the block-like RFID tag can be easily and firmly attached to the metal wire by the insulating sheet.

  In the RFID tag, the loop surface of the loop electrode is formed of the metal wire so that the loop electrode and the metal wire are coupled via a magnetic field, and the metal wire functions as a radiating element. It may be provided along the extending direction. According to this method, by attaching the RFID tag to the metal ring so that the loop surface of the loop electrode is along the circumferential direction of the metal ring, the loop electrode and the metal ring are coupled via a magnetic field. Thus, the metal ring can function more reliably as a radiating element.

  The loop surface of the loop electrode has a longitudinal direction and a short direction, and the RFID tag may be provided so that the longitudinal direction of the loop surface is along the extending direction of the metal wire. Good. According to this method, the degree of coupling between the loop electrode and the metal ring can be improved, and the metal ring can function more reliably as a radiating element.

  Further, when the buffer member is provided on the adhesive layer of the insulating sheet and the insulating sheet is wound so as to cover the RFID tag and the metal wire, the buffer member serves as the RFID tag and the metal wire. And a gap between the insulating sheet and the insulating sheet. According to this method, the strength of the metal ring with an RFID tag can be improved.

  Hereinafter, a metal ring with an RFID tag and a method for attaching the RFID tag according to the embodiment will be described with reference to the accompanying drawings. In the drawings, substantially the same members are denoted by the same reference numerals.

(Embodiment 1)
FIG. 1 is a cross-sectional view showing a schematic configuration of a metal ring with an RFID tag according to Embodiment 1 of the present invention. 2 is a cross-sectional view taken along line A1-A1 of FIG.

  As shown in FIGS. 1 and 2, the metal ring 1 with an RFID tag includes a metal ring 2, an RFID tag 3, and an insulating sheet 4.

  The metal ring 2 is, for example, a ring gear, a seal ring, or a bearing. In the first embodiment, the metal ring 2 has a circular cross section. The circumferential length of the metal ring 2 is, for example, a length of one or more wavelengths of the communication frequency in the 900 MHz band, that is, the UHF band.

  The RFID tag 3 is a small, block-shaped RFID tag having a smaller cross section in the cross section of the metal ring 2. In the first embodiment, the RFID tag 3 is formed in a rectangular parallelepiped shape. The size of the RFID tag 3 is, for example, 2.8 mm × 2.3 mm × 5.5 mm.

  The insulating sheet 4 is a flexible sheet having insulating properties. An adhesive layer 4 a is formed on one main surface of the insulating sheet 4. As shown in FIG. 2, the insulating sheet 4 is wound so as to cover the metal ring 2 and the RFID tag 3 with the adhesive layer 4 a inside. In the first embodiment, the insulating sheet 4 is wound around the entire circumference of the metal ring 2. In addition, the one end 4 b and the other end 4 c of the insulating sheet 4 are connected to each other by the adhesive layer 4 a on the outer peripheral side of the metal ring 2.

  FIG. 3 is an enlarged cross-sectional view of FIG. In addition, illustration of the insulating sheet 4 is abbreviate | omitted in FIG.

  As shown in FIG. 3, the RFID tag 3 includes a resin block 31, an RFIC (Radio Frequency Integrated Circuit) element 32 serving as a power feeding unit, and a loop electrode 33 serving as an antenna element.

  The resin block 31 has a first surface 31A that is an attachment surface (bonding surface) to the metal ring 2, and a second surface 31B that is opposed to the first surface. The resin block 31 is made of, for example, a hard resin material such as an epoxy resin. Moreover, the resin block 31 is formed in a rectangular parallelepiped shape, for example.

  The RFIC element 32 is mounted on one main surface of the substrate 34 so as to be embedded in the second surface 31B of the resin block 31. For example, the RFIC element 32 is an RFIC element corresponding to a communication frequency of 900 MHz band, that is, UHF band. The RFIC element 32 is connected to the loop electrode 33.

  The loop electrode 33 includes a first metal pin 331, a second metal pin 332, a plate electrode 333, a first conductor pattern 334, and a second conductor pattern 335. The loop electrode 33 is configured by connecting a first conductor pattern 334, a first metal pin 331, a plate electrode 333, a second metal pin 332, and a second conductor pattern 335 in series.

  The substrate 34 is provided on the second surface 31 </ b> B side of the resin block 31. In the first embodiment, the substrate 34 is provided so as to be embedded in the second surface 31 </ b> B of the resin block 31. The board | substrate 34 is comprised by hard resin materials, such as an epoxy resin, for example. Moreover, the board | substrate 34 is formed in the rectangular shape, for example.

  In the RFID tag 3, the loop surface of the loop electrode 33 is a circle of the metal ring 2 so that the loop electrode 33 and the metal ring 2 are coupled via a magnetic field, and the metal ring 2 functions as a radiating element. It is provided along the circumferential direction CD. Here, the loop surface is a plane that crosses the first metal pin 331, the second metal pin 332, the flat electrode 333, the first conductor pattern 334, and the second conductor pattern 335, respectively.

  In the first embodiment, the loop surface of the loop electrode 33 has a longitudinal direction and a lateral direction. That is, the extending direction of the flat electrode 333, the first conductor pattern 334, and the second conductor pattern 335 is the longitudinal direction, and the extending direction of the first metal pin 331 and the second metal pin 332 is the short direction. The RFID tag 3 is provided such that the longitudinal direction of the loop surface is along the circumferential direction CD of the metal ring 2.

  The RFID tag 3 and the metal ring 2 may be in contact or may not be in contact. In the first embodiment, the RFID tag 3 is not in contact with the metal ring 2. Further, a protective layer may be provided on the first surface 31 </ b> A of the resin block 31 so as to cover the flat electrode 333.

  In addition, although not shown, two chip capacitors connected to the first conductor pattern 334 and the second conductor pattern 335 are mounted on the substrate 34. The two chip capacitors are arranged in parallel with the RFIC element 32, and the RFIC element 32 is impedance-matched by the loop electrode 33 and the two chip capacitors. The loop electrode 33 and the two chip capacitors constitute an LC resonance circuit.

  Next, a principle of operation in which the loop electrode 33 and the metal ring 2 are coupled via a magnetic field and the metal ring 2 functions as a radiating element will be briefly described. FIG. 4 is a sectional view showing the operation principle.

  When the metal ring 2 receives a radio wave radiated from a reader device (not shown) to read the information of the RFID tag 3, the metal ring 2 is shown in the metal ring 2 in FIG. A current flows through 2. This current generates a magnetic field as shown by the dotted arrow in FIG. This magnetic field flows across the loop surface of the loop electrode 33. As a result, as indicated by a solid arrow in the RFID tag 3 in FIG. 4, a current flows through the loop electrode 33 to generate an electromotive force that activates the RFIC element 32. Information stored in the RFIC element 32 is connected to the loop electrode 33 and the metal ring 2 via a magnetic field, and the metal ring 2 functions as a magnetic field radiation type radiating element. (Not shown). Thereby, the information stored in the RFIC element 32 can be read.

  According to the metal ring 1 with an RFID tag according to the first embodiment, the RFID tag 3 is provided so that the loop surface of the loop electrode 33 is along the circumferential direction CD of the metal ring 2. Thereby, the loop-shaped electrode 33 and the metal ring 2 can be coupled via a magnetic field, so that the metal ring 2 can function more reliably as a radiating element.

  Further, according to the metal ring 1 with an RFID tag according to the first embodiment, the RFID tag 3 is provided so that the longitudinal direction of the loop surface of the loop electrode 33 is along the circumferential direction of the metal ring 2. . Thereby, the coupling degree of the loop electrode 33 and the metal ring 2 can be improved, and the metal ring 2 can function more reliably as a radiation element.

  Moreover, according to the metal ring 1 with an RFID tag according to the first embodiment, the insulating sheet 4 is wound so as to cover the RFID tag 3 and the metal ring 2 with the adhesive layer 4a inside. . As a result, the RFID tag 3 can be easily and firmly secured to the metal ring 2 by the insulating sheet 4 even for the metal ring 2 that does not have a flat surface facing the entire first surface 31 </ b> A serving as the mounting surface of the RFID tag 3. Can be attached to.

  In the metal ring 1 with an RFID tag according to the first embodiment, the size (peripheral length) of the metal ring 2 is sufficiently larger than the size of the RFID tag 3, so that as shown in FIG. The magnetic field radiated from the metal ring 2 can be reduced as the distance from the RFID tag 3 increases. For this reason, as shown in FIG. 6, a plurality of RFID tags 3 may be attached to one metal ring 2. Thereby, a magnetic field can be radiated from the entire circumference of the metal ring 2. In this case, the plurality of RFID tags 3 are preferably attached to the metal ring 2 at equal intervals. Thereby, the magnetic field radiated | emitted from the perimeter of the metal ring 2 can be made more uniform. As a result, even if the reader device (not shown) is brought close to any part of the metal ring 2, the information on the RFID tag 3 can be read more reliably by the reader device. In this case, the identifiers (for example, EPC (Electronic Product Code) and TID (Tag ID)) of the plurality of RFID tags 3 may be the same and attached to the metal ring 2. When it is necessary to further identify between the plurality of RFID tags 3, a part of the identifiers (for example, EPC) of each RFID tag 3 may be rewritten so as to be different from each other.

  Further, in the metal ring 1 with an RFID tag according to the first embodiment, the insulating sheet 4 is wound around the entire circumference of the metal ring 2 as shown in FIG. It is not limited to this. For example, as shown in FIG. 7, the insulating sheet 4 may be wound only on the attachment part of the RFID tag 3 of the metal ring 2.

  Moreover, in the metal ring 1 with an RFID tag according to the first embodiment, as shown in FIG. 2, the one end 4 b and the other end 4 c of the insulating sheet 4 are connected on the outer peripheral side of the metal ring 1. However, the present invention is not limited to this. For example, the one end 4 b and the other end 4 c of the insulating sheet 4 may be connected on the inner peripheral side of the metal ring 1.

  Further, in the metal ring 1 with an RFID tag according to the first embodiment, as shown in FIG. 1, the metal ring 2 is formed in a complete ring shape having no end portion. Is not limited to this. For example, the metal ring 2 may be formed by winding a metal wire in an annular shape. Moreover, the metal ring 2 may have a notch in part. That is, both ends of the metal ring 2 may not be connected. In addition, when providing a notch in a part of metal ring 2, providing in the position away from the RFID tag 3 is preferable. Thereby, the fall of the characteristic as an antenna of metal rings 2 can be controlled.

  Moreover, in the metal ring 1 with an RFID tag according to the first embodiment, as shown in FIG. 2, the metal ring 2 has a circular cross section, but the present invention is not limited to this. For example, the cross section of the metal ring 2 may be a polygon such as a rectangle or a hexagon, or an ellipse. That is, the metal ring 2 may be, for example, a cylindrical metal sleeve (see FIG. 10 described later).

  Moreover, in the metal ring 1 with an RFID tag according to the first embodiment, the RFID tag 3 is attached to the metal ring 2 by the insulating sheet 4, but the present invention is not limited to this. For example, the RFID tag 3 may be attached to the metal ring 2 with an adhesive or the like. Even in this configuration, the RFID tag 3 is provided so that the loop surface of the loop electrode 33 extends along the circumferential direction CD of the metal ring 2, thereby coupling the loop electrode 33 and the metal ring 2 via a magnetic field. Thus, the metal ring 2 can function as a radiating element.

  Moreover, in the metal ring 1 with an RFID tag according to the first embodiment, the RFID tag 3 having the structure shown in FIG. 3 is used, but the present invention is not limited to this. For example, as the RFID tag 3, as shown in FIG. 8A, an RFID tag in which a first metal pin 331 and a first conductor pattern 334, and a second metal pin 332 and a second conductor pattern 335 are arranged shifted in the depth direction. 3A may be used. Further, as shown in FIG. 8B, the RFID tag 3 has a substrate 34 that is smaller in size than the resin block 31, and the first conductor pattern 334 and the second conductor pattern 335 are formed on the second surface 31B of the resin block 31 and the substrate 34. An RFID tag 3B formed on the other main surface may be used. Further, as the RFID tag 3, as shown in FIG. 8C, an RFID tag 3C having a loop electrode formed in a coil shape by dividing the flat electrode 333 into a plurality of pieces may be used. In this case, the loop electrode includes a plurality of flat electrodes 333, a plurality of first metal pins 331, a plurality of second metal pins 332, a first conductor pattern 334, a second conductor pattern 335, and a substrate 34. A plurality of third conductor patterns 336 formed on the other main surface of the first conductor pattern 336 are connected in series. 8A to 8C, the resin block 31 is shown in a transparent manner, and only the components constituting the loop electrode are hatched.

  Next, an example of a method for attaching the RFID tag 3 to the metal ring 2 will be described. 9A and 9B are cross-sectional views showing the attachment method.

  First, as shown in FIG. 9A, the block-like RFIC tag 3 is supported on the adhesive layer 4 a of the insulating sheet 4.

  Next, as shown in FIG. 9B, the insulating sheet 4 is wound so as to cover the RFID tag 3 and the metal ring 2 with the adhesive layer 4 a inside. At this time, as shown in FIG. 3, the RFID tag 3 is arranged so that the loop surface of the loop electrode 33 is along the extending direction (circumferential direction CD) of the metal ring 2. More specifically, the RFID tag 3 is disposed such that the longitudinal direction of the loop surface of the loop electrode 33 is along the extending direction (circumferential direction CD) of the metal ring 2.

  As a result, as shown in FIG. 2, one end 4b and the other end 4c of the insulating sheet 4 are connected to each other by the adhesive layer 4a on the outer peripheral side of the metal ring 2, and the RFID tag 3 is connected to the metal ring. 2 is attached.

  According to the method of attaching the RFID tag 3 according to the first embodiment, the block-like RFID tag 3 can be easily and firmly attached to the metal ring 2 by the insulating sheet 4.

  Further, according to the method of attaching the RFID tag 3 according to the first embodiment, the RFID tag 3 is provided so that the loop surface of the loop electrode 33 is along the extending direction of the metal ring 2. Thereby, the loop-shaped electrode 33 and the metal ring 2 can be coupled via a magnetic field, so that the metal ring 2 can function more reliably as a radiating element.

  Further, according to the method for attaching the RFID tag 3 according to the first embodiment, the longitudinal direction of the loop surface of the loop electrode 33 is provided along the extending direction of the metal ring 2. Thereby, the coupling degree of the loop electrode 33 and the metal ring 2 can be improved, and the metal ring 2 can function more reliably as a radiation element.

  Although the RFID tag 3 is attached to the metal ring 2 in the method for attaching the RFID tag 3 according to the first embodiment, the present invention is not limited to this. By using the insulating sheet 4, even for a metal wire that does not have a flat surface facing the entire first surface 31 </ b> A of the RFID tag 3, for example, an arc-shaped wire or a wire with a rectangular cross section with a small width, The tag 3 can be easily and firmly attached.

  Next, the article management system 100 using the metal ring 1 with an RFID tag according to the first embodiment will be described. FIG. 10 is a perspective view showing a schematic configuration of an article management system 100 using the metal ring 1 with an RFID tag according to the first embodiment. In the XYZ coordinate system shown in the drawing, the Z-axis direction indicates the height direction, and the X-axis direction and the Y-axis direction indicate the horizontal direction. This XYZ coordinate system is intended to facilitate understanding of the invention and is not intended to limit the invention.

  The article management system 100 is a system that manages a plurality of articles using the metal ring 1 with an RFID tag. Below, the metal ring 2 is a cylindrical metal sleeve and the RFID tag 3 is attached to the inner peripheral side of the metal ring 1 as an example. Note that the insulating sheet 4 is not shown in consideration of easy viewing of the drawing.

  As shown in FIG. 10, the article management system 100 includes an article holder 101 that holds a plurality of metal rings 1 with RFID tags, and a reader device 102.

  The article holder 101 includes a main body part 111, two arm parts 112 extending from the main body part 111 in a lateral direction and on which a plurality of metal rings 1 with RFID tags are hung, and a cable antenna 113. .

  A plurality of casters 114 are attached to the main body 111 so that the article holder 101 can travel. The two arm portions 112 are arranged in parallel in the height direction (Z direction), and are attached to the main body portion 111 so as to extend in the horizontal direction (Y-axis direction), respectively.

  The cable antenna 113 is an antenna for performing wireless communication with the RFID tag 3. The cable antenna 113 is attached along the lower portion of the arm portion 112 so as to be positioned inside the plurality of metal rings 1 with RFID tags that are hung on the arm portion 112. The base end portion of the cable antenna 113 is connected to the auxiliary antenna 115. The auxiliary antenna 115 is attached to the main body 111.

  The reader device 102 is, for example, a portable handy device. In the first embodiment, the reader device 102 does not perform wireless communication directly with the RFID tag 3 but performs wireless communication with the RFID tag 3 via the cable antenna 113 and the auxiliary antenna 115. Each RFID tag 3 stores information on the metal ring 2 to which the RFID tag 3 is attached, for example, information such as an identification number, a lot number, and a manufacturing date.

  FIG. 11 is a cross-sectional view showing a schematic configuration of the cable antenna 113 and the auxiliary antenna 115. In FIG. 11, hatching is omitted for some components in consideration of easy viewing of the drawing.

  As shown in FIG. 11, the cable antenna 113 includes a cable part 121, a matching circuit part 122, and a magnetic body 123.

  The cable unit 121 is a part that functions as an antenna that transmits and receives radio waves (signals) S. The cable portion 121 has a so-called coaxial cable shape, for example, an inner conductor 124 such as a copper wire, an insulator 125 that covers the inner conductor 124, and an outer conductor 126 such as a copper mesh that covers the insulator 125. It has. That is, the outer conductor 126 is spaced apart from the inner conductor 124 (so that the characteristic impedance of the signal conductor is constant (eg, 50Ω)), and the extending direction of the cable antenna 113 (with the inner conductor 124 ( (Y-axis direction). A sheath (not shown) made of an insulating material may be provided outside the outer conductor 126.

  The matching circuit unit 122 is provided at the distal end portion 113 a of the cable antenna 113. The matching circuit unit 122 is configured to be connected between one end of the inner conductor 124 of the cable unit 121 and one end of the outer conductor 126 to perform impedance matching.

  In the first embodiment, the matching circuit unit 122 is configured as a circuit board. Specifically, the matching circuit unit 122 includes an insulating substrate 131, a front-side electrode 132 formed on one surface of the insulating substrate 131, and a back-side electrode 133 formed on the other surface of the insulating substrate 131. It is configured as a substrate.

  One end of the cable portion 121 of the cable antenna 113 is attached to one surface of the insulating substrate 131, that is, a portion of the surface where the front electrode 132 is not present. The inner conductor 124 of the cable portion 121 is electrically (direct current) connected to the front electrode 132.

  The front-side electrode 132 that is electrically connected to the inner conductor 124 of the cable part 121 is electrically (DC) connected to the back-side electrode 133 via an interlayer connector 134 such as a via-hole conductor formed on the insulating substrate 131. Yes.

  In addition, a part of the back electrode 133 faces the external conductor 126 of the cable portion 121 with the insulating substrate 131 interposed therebetween, and a capacitance is formed between them (capacitive coupling).

  FIG. 12 shows an equivalent circuit of the matching circuit unit 122. As shown in FIG. 12, the equivalent circuit of the matching circuit unit 122 includes a capacitance C and an inductance L. Capacitance C is realized by capacitively coupling a part of the back-side electrode 133 to the external conductor 126 of the cable unit 121 with the insulating substrate 131 interposed therebetween. The inductance L is realized by the parasitic inductances of the front side electrode 132, the back side electrode 133, and the interlayer connector 134, and the like.

  The thickness of the insulating substrate 131, the size (area) of the portion of the back electrode 133 that faces the external conductor 126 across the insulating substrate 131, the size and shape of the front electrode 132 and the back electrode 133, and the thickness of the interlayer connector 134 By appropriately determining the above, a desired capacitance C and inductance L can be obtained. Thereby, the matching circuit unit 122 can achieve impedance matching between the inner conductor 124 and the outer conductor 126 so that transmission loss is suppressed at the communication frequency of the RFID tag 3.

  According to such a cable antenna 113, even if it is in contact with or close to a metal body (metal arm portion 112) or surrounded by a metal body (metal ring 2), it can be used as an antenna of another structure. Compared to communication characteristics, it is less affected.

  The magnetic body 123 is a sleeve-shaped member made from a magnetic material. The magnetic body 123 is extrapolated to the cable portion 121. The magnetic body 123 is used to limit a portion of the cable antenna 113 from which the radio wave S is radiated (or receives the radio wave). Specifically, the radio wave S is radiated from the radio wave radiation portion 113b of the cable antenna 113 from the magnetic body 123 to the tip portion 113a. On the other hand, emission of radio waves from the portion from the magnetic body 123 to the base end side is suppressed.

  As shown in FIG. 11, the auxiliary antenna 115 connected to the cable antenna 113 is, for example, a patch antenna, and a radiation plate 141 that transmits and receives the radio wave S, and a ground that is disposed at a distance from the radiation plate 141. A plate 142. The other end of the inner conductor 124 of the cable portion 121 of the cable antenna 113 is electrically (direct current) connected to the radiation plate 141 of the auxiliary antenna 115 as a power feeding portion of the cable antenna 113. The other end of the external conductor 126 is connected to the ground plate 142. The ground plate 142 is grounded.

  The cable antenna 113 and the auxiliary antenna 115 function as a so-called repeater in communication between the reader device 102 and the RFID tag 3. That is, as shown in FIG. 11, the radio wave S from the reader device 102 is received by the radiation plate 141 of the auxiliary antenna 115 and radiated from the external conductor 126 of the cable portion 121 of the cable antenna 113. The radio wave S radiated from the external conductor 126 reaches the RFID tag 3.

  On the other hand, the radio wave from the RFID tag 3 is received by the outer conductor 126 of the cable portion 121 of the cable antenna 113 and transmitted from the radiation plate 141 of the auxiliary antenna 115 toward the reader device 102.

  In the first embodiment, the cable antenna 113 has a coaxial cable structure. However, the present invention is not limited to this, and the cable antenna 113 may have a flat cable structure, a leaky coaxial cable structure, or the like. Good.

  In the first embodiment, the reader device 102 has a reader function of reading information of the RFID tag 3, but the present invention is not limited to this. For example, the reader device 102 may be configured to have a reader / writer function of reading information from the RFID tag 3 and writing information to the RFID tag 3.

(Embodiment 2)
FIG. 13 is an enlarged cross-sectional view showing a schematic configuration of a metal ring 1A with an RFID tag according to Embodiment 2 of the present invention. The metal ring 1A with an RFID tag according to the second embodiment is different from the metal ring 1 with an RFID tag according to the first embodiment in the gap between the RFID tag 3, the metal ring 2, and the adhesive layer 4a. The buffer member 5 is provided. The buffer member 5 is made of, for example, a rubber material or a foam material.

  According to the metal ring 1A with an RFID tag according to the second embodiment, the buffer member 5 can eliminate a gap between the RFID tag 3, the metal ring 2, and the adhesive layer 4a. Thereby, the intensity | strength of the metal ring 1 with an RFID tag can be improved.

  Next, an example of a method for attaching the RFID tag 3 to the metal ring 2 will be described. 14A and 14B are cross-sectional views showing the attachment method.

  First, as shown in FIG. 14A, the buffer member 5 is provided on the adhesive layer 4 a of the insulating sheet 4, and the block-like RFIC tag 3 is supported by the buffer member 5. At this time, the one end 4 b and the other end 4 c of the insulating sheet 4 are exposed so as not to be covered by the buffer member 5.

  Next, as shown in FIG. 14B, the insulating sheet 4 is wound so as to cover the RFID tag 3 and the metal ring 2 with the adhesive layer 4 a inside. At this time, as shown in FIG. 3, the RFID tag 3 is arranged so that the loop surface of the loop electrode 33 is along the extending direction (circumferential direction CD) of the metal ring 2. More specifically, the RFID tag 3 is disposed such that the longitudinal direction of the loop surface of the loop electrode 33 is along the extending direction (circumferential direction CD) of the metal ring 2.

  Thereby, as shown in FIG. 13, the one end 4b and the other end 4c of the insulating sheet 4 are connected to each other by the adhesive layer 4a on the outer peripheral side of the metal ring 2, and the RFID tag 3 is connected to the metal ring. 2 is attached. Further, when the insulating sheet 4 is wound so as to cover the RFID tag 3 and the metal ring 2, the buffer member 5 is deformed so as to fill a gap between the RFID tag 3, the metal ring 2 and the insulating sheet 4. . Thereby, the intensity | strength of the metal ring 1 with an RFID tag can be improved.

  While the invention has been described in certain embodiments with a certain degree of detail, the disclosure of these embodiments should vary in configuration details. In addition, combinations of elements and changes in the order in each embodiment can be realized without departing from the scope and spirit of the present disclosure.

  According to the present invention, the metal ring can function more reliably as a radiating element, which is useful for applications such as process management and physical distribution management of articles provided with the metal ring.

1, 1A Metal ring with RFID tag 2 Metal ring 3, 3A, 3B, 3C RFID tag 4 Insulating sheet 4a Adhesive layer 4b One end 4c Other end 5 Buffer member 31 Resin block 31A First surface 31B Second surface 32 RFIC element 33 Loop electrode 34 Substrate 100 Article management system 101 Article holder 102 Reader device 111 Main body part 112 Arm part 113 Cable antenna 113a Tip part 113b Radio wave radiation part 114 Caster 115 Auxiliary antenna 121 Cable part 122 Matching circuit part 123 Magnetic Body 124 Internal conductor 125 Insulator 126 External conductor 131 Insulating substrate 132 Front side electrode 133 Back side electrode 134 Interlayer connector 141 Radiation plate 142 Ground plate 331 First metal pin 332 Second metal pin 333 Flat electrode 334 First conductor pattern 33 The second conductive pattern 336 third conductor pattern

Claims (3)

A metal ring having a circumference of one or more wavelengths of the UHF band communication frequency;
A plurality of RFID tags having a UHF band RFIC element and a loop electrode connected to the RFIC element , spaced apart from each other with respect to the metal ring ;
An annular insulating sheet having an adhesive layer;
With
Wherein each of the plurality of RFID tags, loop plane of the loop electrode is provided along the circumferential direction of the metal ring, and the loop electrode and the metal ring is linked via a magnetic field The metal ring functions as a radiating element;
The insulating sheet covers the entire circumference of the plurality of RFID tags and the metal ring with the adhesive layer inside, and one end portion and the other end portion of the insulating sheet in the width direction of the metal ring. It is attached to be connected by the adhesive layer on the inner peripheral side or outer peripheral side,
Metal ring with RFID tag. The loop surface of the loop electrode has a longitudinal direction and a short direction,
2. The metal ring with an RFID tag according to claim 1, wherein the RFID tag is provided such that a longitudinal direction of the loop surface is along a circumferential direction of the metal ring. Further comprising, RFID-tagged metal ring according to claim 1 or 2 buffer member filling a gap between the adhesive layer and the RFID tag and the metal ring.

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