JP2023077961A - RFID tag - Google Patents

Abstract

An object of the present invention is to provide an RFID tag capable of suppressing breakage of an antenna portion even when an external force is applied. An RFID tag (10) has an antenna part (20) extending along a predetermined shape, and the antenna part (20) has a plurality of antenna pieces (22) arranged side by side in the extending direction. ing. Antenna pieces adjacent to each other in the extending direction are electrically connected to each other. The RFID tag further comprises a first substrate (12A) and a second substrate (12B) overlapping each other. The antenna piece includes a plurality of first forming pieces (23) and second forming pieces (24) alternately arranged in the extending direction. A first formation piece is formed on the opposite side (12A1) of the first substrate and a second formation piece is formed on the opposite side (12B1) of the second substrate. [Selection drawing] Fig. 3

Description

The present invention relates to RFID tags.

For example, an RFID (Radio Frequency Identifier) tag comprises an antenna and a semiconductor chip. Electromagnetic waves received by the antenna activate the semiconductor chip, and an external device reads the ID information stored in the semiconductor chip to manage articles. (see, for example, Patent Document 1).

JP 2010-26885 A

Applications of RFID tags include, for example, management of linen products such as clothes and sheets. RFID tags used for managing linen products are subject to physical stress when an external force is applied during a washing process. For this reason, in particular, an antenna in which a conductor is formed in a linear shape has the problem of being cut or damaged by stress. In the above, the problem of RFID tags used for managing linen products has been described, but the present invention is not limited to this, and similar problems arise in RFID tags to which external force is applied.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a technique capable of suppressing breakage of an antenna section even when an external force is applied.

One aspect of the present invention is an RFID tag having an antenna portion extending along a predetermined shape from an IC chip, wherein the antenna portion is formed by a plurality of antenna pieces arranged side by side in the extending direction, The antenna pieces adjacent to each other in the extending direction are electrically connected to each other.

According to one aspect of the present invention, breakage of the antenna section can be suppressed even when an external force is applied.

1 is a plan view of an RFID tag in an embodiment; FIG. 1 is a schematic exploded perspective view of an RFID tag in an embodiment; FIG. 3A is a partially enlarged plan view of the antenna section in the embodiment, and FIG. 3B is an exploded cross-sectional view taken along arrow A in FIG. 3A. 4 is a partially schematic exploded perspective view of the antenna section in the embodiment; FIG. 5A and 5B are explanatory diagrams when the first forming piece and the second forming piece are relatively displaced. FIG. 5B is an explanatory view similar to FIG. 5A of the first forming piece and the second forming piece in the first modified example; FIG. 7A is a cross-sectional view similar to FIG. 3B of the RFID tag in the second modification, and FIG. 7B is a cross-sectional view similar to FIG. 3B of the RFID tag in the third modification. It is a figure which shows the variation of the shape of an antenna piece. FIG. 5B is an explanatory view similar to FIG. 5A of a first forming piece and a second forming piece in a fourth modified example;

Hereinafter, RFID tags according to embodiments will be described in detail with reference to the accompanying drawings. It should be noted that the present invention is not limited to the following embodiments, and can be modified appropriately without changing the gist of the invention. In the following diagrams, part of the configuration may be omitted for convenience of explanation.

FIG. 1 is a plan view of an RFID tag according to an embodiment. FIG. 2 is a schematic exploded perspective view of the RFID tag according to the embodiment. As shown in FIG. 1, an RFID tag 10 according to this embodiment includes a substrate 12, an IC (Integrated Circuit) chip 14, and an antenna section 20. As shown in FIG. The RFID tag 10 is used for product management and the like by having the IC chip 14 operate by electromagnetic waves received by the antenna unit 20 and having an external device read the ID information stored in the IC chip 14 .

The base material 12 has a rectangular shape in plan view, and in each figure, the arrow X, the arrow Y, and the arrow Z (see FIGS. 2 and 3, etc.) indicate the length direction (longitudinal direction) and the width direction of the base material 12. (transverse direction) and the thickness direction are shown, respectively. The width direction of the base material 12 is a direction perpendicular to the length direction of the base material 12 when viewed from above, and the thickness direction of the base material 12 is the length of the base material 12 when viewed from the side. It is the direction orthogonal to the direction. The length direction, width direction, and thickness direction of the base material 12 are the same as the length direction, width direction, and thickness direction of the RFID tag 10 .

The base material 12 includes a first base material 12A and a second base material 12B that overlap each other in the thickness direction. The first base material 12</b>A and the second base material 12</b>B are formed in a rectangular shape having the same planar shape as the base material 12 . Further, the first base material 12A and the second base material 12B are formed by making a flexible material made of resin such as PET into a sheet shape (plate shape). 12 A of 1st base materials and the 2nd base material 12B have the opposing surface 12A1 and the opposing surface 12B1 as one surface of the thickness direction. The first base material 12A and the second base material 12B are integrated to form the base material 12 by bonding the respective facing surfaces 12A1 and 12B1.

The IC chip 14 is mounted on the opposing surface 12A1 of the first base material 12A by adhesion or the like. The IC chip 14 is arranged substantially in the center in the length direction and width direction of the first base material 12A and electrically connected to the antenna section 20 .

The antenna section 20 extends from two positions of the IC chip 14 in a predetermined shape in a U-shape or a J-shape in a plan view (see FIG. 1). The extension direction of the antenna section 20 is an example, and various extension directions (linear direction, spiral direction, etc.) used for antenna wiring of RFID tags can be adopted. The antenna section 20 can be exemplified by being made of a metal material such as silver paste or aluminum foil.

Further, the antenna section 20 can be formed by printing conductive ink (conductive material). Examples of conductive inks include those containing silver as a main component. The conductive ink can be printed in the shape of the antenna piece 22 to be described later, and as long as a predetermined resistance value as the antenna section 20 can be obtained, silk screen printing or gravure printing may be used.

Next, a specific configuration of the antenna section 20 will be described below.

As shown in FIG. 1, the antenna section 20 is formed by a plurality of antenna pieces 22 arranged side by side in the extending direction. In other words, the antenna section 20 is formed like a linear antenna wiring by arranging a plurality of small individual antenna pieces 22 that are separate from each other. An example of the size of the antenna piece 22 is a size that fits in the IC chip 14 .

As shown in FIG. 2, the antenna piece 22 includes a plurality of first forming pieces 23 formed on the facing surface 12A1 of the first base material 12A and a plurality of second forming pieces 23 formed on the facing surface 12B1 of the second base material 12B. 2 forming pieces 24; Each forming piece 23, 24 is formed in a planar shape similar to a wedge shape, and a detailed description of such a planar shape will be given later.

FIG. 3A is a partially enlarged plan view of the antenna section. 3B is an exploded cross-sectional view of FIG. 3A as viewed from arrow A. FIG. In each figure, including FIGS. 3A and 3B, the first forming piece 23 is hatched so as to be easily distinguished from the second forming piece 24. As shown in FIG. As also shown in FIGS. 3A and 3B, the first forming pieces 23 and the second forming pieces 24 are alternately arranged in the extending direction of the antenna section 20 . Therefore, the first formation piece 23 becomes the antenna piece 22 arranged every other one in the arrangement direction among the plurality of antenna pieces 22 arranged side by side. Further, the second formation piece 24 also serves as the antenna piece 22 that is arranged alternately in the arrangement direction among the plurality of antenna pieces 22 that are arranged side by side. Then, in a state in which the first base material 12A and the second base material 12B (not shown in FIG. 3A) are superimposed, the second formation pieces 24 are positioned between the first formation pieces 23 adjacent in the alignment direction. , the first forming piece 23 is positioned between the adjacent second forming pieces 24 at .

When the first forming piece 23 and the second forming piece 24 are overlapped, the first forming piece 23 and the second forming piece 24 that are adjacent in the extending direction of the antenna portion 20 partially overlap and are in surface contact with each other. be. As a result, the first forming piece 23 and the second forming piece 24 (antenna pieces 22) adjacent to each other in the extending direction of the antenna portion 20 are electrically connected.

Here, the first forming piece 23 and the second forming piece 24 are formed in the same planar shape. Therefore, hereinafter, each component of the first forming piece 23 will be described, and each component of the second forming piece 24 will be represented by the ones digit "3 ” may be changed to “4” and the explanation may be omitted.

FIG. 4 is a partially schematic exploded perspective view of the antenna section in the embodiment. As shown in FIG. 4, the first forming piece 23 is formed in an outer peripheral shape having a front end 23a, a rear end 23b, a pair of oblique sides (connecting ends) 23c, and a recessed portion 23d. ing.

The front end 23a is the end that is gradually tapered in the extending direction of the antenna section 20, and the rear end 23b is the end opposite to the front end 23a. In the first forming piece 23, the front end 23a and the rear end 23b are both ends in the extending direction of the antenna portion 20. As shown in FIG. The pair of oblique sides 23c extend in a direction connecting the tip 23a and the rear end 23b, and extend in a direction approaching toward the tip 23a. The recess 23d is formed in the rear end 23b.

As shown in FIGS. 3A and 3B, in the first forming piece 23 and the second forming piece 24 adjacent in the extending direction of the antenna section 20, a part of the periphery of the tip 23a of the first forming piece 23 is the second forming piece. It overlaps a portion of the piece 24 near the tip 24a from the recess 24d. In addition, in the first formation piece 23 and the second formation piece 24 that are adjacent in the same direction, a portion of the periphery of the tip 24a of the second formation piece 24 overlaps with a portion of the first formation piece 23 near the tip 23a from the recess 23d. . By overlapping in this manner, the adjacent first formation piece 23 and second formation piece 24 are in surface contact, and are electrically connected so as to allow current to flow between them, thereby forming a single unit extending in a predetermined direction. It exhibits the same reception function as antenna wiring.

With the first forming piece 23 and the second forming piece 24 overlapping each other, the pair of oblique sides 23c of the first forming piece 23 are arranged adjacent to or in the vicinity of the forming edge of the recess 24d of the second forming piece 24, and the oblique sides 23c It is hooked and fitted with the concave portion 24d. Also, the pair of oblique sides 24c of the second forming piece 24 are arranged adjacent to or in the vicinity of the formation edge of the recess 23d of the first forming piece 23, and the oblique sides 24c are hooked and fitted to the recess 23d.

FIGS. 5A and 5B are explanatory diagrams when the first forming piece and the second forming piece are relatively displaced, FIG. 5A showing the state before the relative displacement, and FIG. 5B showing the state after the relative displacement. In the RFID tag 10, when an external force is applied to the base material 12, the first base material 12A and the second base material 12B may be displaced in the X direction and the Y direction. In such a case, for example, the first formation piece 23 and the second formation piece 24 are relatively displaced from the position shown in FIG. 5A to the position shown in FIG. .

5B, the periphery of the tip 23a of the first formation piece 23 and the recess 24d of the second formation piece 24 are separated, and the periphery of the tip 24a of the second formation piece 24 and the recess 23d of the first formation piece 23 are separated. It will happen. However, the periphery of the oblique side 23c of the first formation piece 23 and the periphery of the rear end 24b of the second formation piece 24 are overlapped, and the periphery of the oblique side 24c of the second formation piece 24 and the periphery of the rear end 23b of the first formation piece 23 are overlapped. can be maintained. As a result, the first forming piece 23 and the second forming piece 24 (antenna pieces 22) adjacent to each other in the extending direction of the antenna portion 20 can be maintained in an electrically connected state.

In particular, in the configuration of the present embodiment, it is possible to reduce the change in the overlapping area of the adjacent first forming piece 23 and second forming piece 24 between the position shown in FIG. 5A and the position shown in FIG. 5B. In this arrangement, concave portions 23d and 24d are formed at the positions shown in FIG. 5A, and the adjacent first forming piece 23 and second forming piece 24 are overlapped at portions near the tips 23a and 24a from the concave portions 23d and 24d. It depends on the configuration. Also, the oblique sides 23c and 24c make the first forming piece 23 and the second forming piece 24 thinner toward the tips 23a and 24a. With such a configuration, after the relative displacement in FIG. 5B, the area where the first forming piece 23 and the second forming piece 24 overlap is around the recesses 23d and 24d, and the change in the overlapping area can be reduced.

Here, the configuration of FIG. 6, which is the first modified example, and the configuration of the above embodiment will be compared. FIG. 6 is an explanatory view similar to FIG. 5A of the first forming piece and the second forming piece in the first modified example. The first forming piece 33 and the second forming piece 34 in the first modified example of FIG. 6 are formed in a rectangular planar shape. For comparison, the first forming piece 33 and the second forming piece 34 have the same plane area as the first forming piece 23 and the second forming piece 24 of the above embodiment, and the width in the Y direction is the above. It is formed to have the same width in the Y direction as the rear ends 23b and 24b of the embodiment.

In the above-described embodiment, the first forming piece 23 and the second forming piece 24 are wedge-shaped, so that the leading ends 23a and 24a, which are the one ends in the X direction, are narrower in the Y direction than the trailing ends 23b and 24b. On the other hand, in the first modification shown in FIG. 6, the first forming piece 33 and the second forming piece 34 are rectangular, so that the width in the Y direction is the same on one end in the X direction and can be increased with

Therefore, in the first modified example, the width in the Y direction of the region where the first formation piece 33 and the second formation piece 34 overlap each other can be made larger than in the above embodiment. As a result, the relative displacement in the Y direction between the first formation piece 33 and the second formation piece 34 can increase the amount of displacement that allows the contact to be maintained, compared to the above-described embodiment.

On the other hand, in the relative displacement of the first forming piece 33 and the second forming piece 34 in the X direction, the amount of displacement capable of maintaining contact therebetween changes according to the width of the overlapping region in the X direction. In other words, by adjusting the spacing between the adjacent first formation piece 33 and second formation piece 34, the displacement amount that can maintain contact in the X direction can be changed.

By changing the planar shape and arrangement of the forming pieces 23, 24, 33, and 34 in this way, it is possible to change the range in which contact can be maintained against the displacement of the first base material 12A and the second base material 12B. can. As a result, it is possible to provide variations capable of coping with various deviations according to the external force applied to the base material 12 and the mode of use of the RFID tag 10 .

As described above, in the above-described embodiment, the antenna section 20 is formed by the plurality of antenna pieces 22 (the first forming piece 23 and the second forming piece 24), and the first antennas adjacent to each other in the extending direction of the antenna section 20 are formed. The forming piece 23 and the second forming piece 24 are brought into contact with each other. As a result, while the antenna section 20 has the same reception function as conventional antenna wiring, the relative displacement of the adjacent first forming piece 23 and second forming piece 24 is allowed. Therefore, for example, even if the RFID tag 10 is attached to a linen product and washed, and the base material 12 is deformed by the external force caused by the washing, the relative displacement of the first forming piece 23 and the second forming piece 24 causes stress on the antenna portion 20. is less likely to occur, and breakage of the antenna section 20 can be suppressed. As a result, even if an external force is applied to the RFID tag 10, the adjacent first forming piece 23 and second forming piece 24 can maintain the electrically connected state, and damage such that the antenna portion 20 cannot receive normally can be prevented. can be prevented.

Further, as shown in FIG. 5A, the oblique side 23c of the first forming piece 23 is hooked with the recessed portion 24d of the second forming piece 24, and the oblique side 24c of the second forming piece 24 is hooked with the recessed portion 23d of the first forming piece 23. It is possible to easily maintain the state shown in FIG. 5A as the antenna section 20 .

It should be noted that the present invention is not limited to the above-described embodiments, and can be implemented with various modifications. In each of the above embodiments, the sizes, shapes, directions, etc. shown in the accompanying drawings are not limited to these, and can be changed as appropriate within the scope of exhibiting the effects of the present invention. In addition, it is possible to carry out by appropriately modifying the present invention as long as it does not deviate from the scope of the purpose of the present invention.

In the above-described embodiment, the adjacent first forming piece 23 and second forming piece 24 can adopt a configuration in which they are physically separated from each other as long as they are in an electrically connected state. As such a configuration, a second modified example shown in FIG. 7A and a third modified example shown in FIG. 7B can be exemplified. FIG. 7A is a cross-sectional view similar to FIG. 3B of the RFID tag in the second modification, and FIG. 7B is a cross-sectional view similar to FIG. 3B of the RFID tag in the third modification.

The second modification shown in FIG. 7A is configured using an anisotropic conductive film 40 in which conductive particles 42 are dispersed inside a base film 41 made of a thermosetting resin as an adhesive. In the second modification, an anisotropic conductive film 40 is interposed between the first base material 12A and the second base material 12B on which the first formation piece 23 and the second formation piece 24 are formed, and the two are joined together. By such bonding, the anisotropic conductive film 40 is arranged in the portion where the first forming piece 23 and the second forming piece 24 overlap in the thickness direction.

By applying heat and pressure in this state, the first forming piece 23 and the second forming piece 24 are adhered to each other by the base film 41 at the overlapping portions (without contact) in the thickness direction. In such an adhesive state, in the anisotropic conductive film 40, the insulating coat on the outermost surface of the conductive particles 42 is broken only in the regions where the first forming pieces 23 and the second forming pieces 24 overlap. Therefore, the area where the first forming piece 23 and the second forming piece 24 are overlapped conducts electricity through the nickel, gold, or the like coated around the nuclei of the conductive particles 42 . Thereby, the first formation piece 23 and the second formation piece 24 are electrically connected via the conductive particles 42 .

In areas where the first forming piece 23 and the second forming piece 24 do not overlap, the insulating coat of the conductive particles 42 is maintained. Thus, insulation can be ensured by the anisotropic conductive film 40 in regions other than the region where the first forming piece 23 and the second forming piece 24 overlap. In the second modification, the conductive particles 42 can electrically connect the first forming piece 23 and the second forming piece 24 adjacent to each other while strengthening the bonded state of the adjacent first forming piece 23 and the second forming piece 24 by the base film 41 .

The configuration for electrically connecting the first forming piece 23 and the second forming piece 24 via the conductive particles is not limited to the above, and various modifications are possible. Carbon powder (pieces) or metal powder (pieces) may be sprinkled on the area where the second forming pieces 24 overlap to seal.

The third modification shown in FIG. 7B is configured such that adjacent first forming pieces 23 and second forming pieces 24 are separated from each other without physically contacting each other and are electrically connected by capacitive coupling. In the third modification, a first formation piece 23 and a second formation piece 24 that are adjacent in the extending direction of the antenna section 20 and separated in the thickness direction form a capacitor C, and the antenna section 20 receives signals through the capacitor C. high-frequency electromagnetic waves are transmitted. Adjacent first formation piece 23 and second formation piece 24 can be electrically connected even with such a capacitively coupled configuration. Further, even if the first forming piece 23 and the second forming piece 24 are relatively displaced due to the displacement of the first base material 12A and the second base material 12B, the adjacent first forming pieces 23 may be displaced in the same manner as in the above-described embodiment. and the electrical connection of the second forming piece 24 can be maintained.

Further, the planar shape of the antenna piece 22 is not limited to the shape of the above-described embodiment or the first modification shown in FIG. 6, and various shapes as shown in FIG. 8 may be adopted. FIG. 8 is a diagram showing variations in the shape of the antenna piece. As shown in FIG. 8, for example, the antenna piece 22 may have a polygonal shape such as a triangular shape, a square shape, a trapezoidal shape, a hexagonal shape, or the like. Further, the polygonal antenna piece 22 may have a shape in which some sides are curved, or may have a star shape. Furthermore, the antenna piece 22 may have a circular shape, a semicircular shape, an elliptical shape, or a shape similar to a substantially ellipse, such as an oval shape or an oval shape.

FIG. 9 is an explanatory view similar to FIG. 5A of the first forming piece and the second forming piece in the fourth modification. In the fourth modified example of FIG. 9, the first forming piece 23 and the second forming piece 24 are formed in a hexagonal shape. In the fourth modification, a plurality of (three in FIG. 9) first formation pieces 23 and second formation pieces 24 are formed in the Y direction (the direction perpendicular to the extending direction of the antenna section 20), and are adjacent to each other in the Y direction. The first forming pieces 23 and the second forming pieces 24 overlap each other and are electrically connected to each other. In addition, in the fourth modification, the first forming piece 23 and the second forming piece 24 adjacent to each other in the extending direction of the antenna section 20 are electrically connected in the same manner as in the above-described embodiment. Also in the fourth modification, the shapes of the first forming piece 23 and the second forming piece 24 are not particularly limited, and may be changed to the shape shown in FIG.

Furthermore, in the antenna section 20, some of the antenna pieces 22 may be formed in different shapes instead of forming the plurality of antenna pieces 22 in the same shape.

10: RFID tag 12A: first base material 12A1: opposite surface 12B: second base material 12B1: opposite surface 14: IC chip 20: antenna part 22: antenna piece 23: first formation piece 23c: oblique side (connection end)
23d: concave portion 24: second forming piece 24c: hypotenuse (connection end)
24d: concave portion 33: first forming piece 34: second forming piece 42: conductive particles

Claims (9)

An RFID tag having an antenna portion extending along a predetermined shape from an IC chip,
The antenna section is formed by a plurality of antenna pieces arranged side by side in the extending direction,
The RFID tag, wherein the antenna pieces adjacent to each other in the extending direction are electrically connected to each other. further comprising a first substrate and a second substrate each having opposing surfaces overlying each other;
the antenna piece includes a plurality of first forming pieces and second forming pieces alternately arranged in the extending direction;
2. The RFID according to claim 1, wherein said first forming piece is formed on said facing surface of said first substrate, and said second forming piece is formed on said facing surface of said second substrate. tag. 3. The RFID tag according to claim 2, wherein the first forming piece and the second forming piece that are adjacent in the extending direction are partially overlapped and electrically connected. 4. The RFID tag according to claim 2, wherein the antenna piece is formed by printing a conductive material on the first base material and the second base material. 5. The RFID tag according to any one of claims 1 to 4, wherein said antenna pieces adjacent to each other in said extending direction are electrically connected through surface contact. 5. The RFID tag according to any one of claims 1 to 4, wherein the antenna pieces adjacent to each other in the extending direction are electrically connected via conductive particles. 5. The RFID tag according to claim 1, wherein said antenna pieces adjacent to each other in said extending direction are electrically connected by capacitive coupling. The antenna piece is formed in an outer peripheral shape having a connecting end extending in a direction connecting both ends in the extending direction and a recess formed at one end in the extending direction,
6. The RFID tag according to any one of claims 1 to 5, wherein the connecting end of one of the antenna pieces adjacent in the extending direction is hooked in the recess of the other. 9. The antenna piece according to any one of claims 1 to 8, wherein the planar shape of the antenna piece is formed by at least one of a polygonal shape, a circular shape, a semicircular shape, and an elliptical shape. RFID tag.

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