JP2023006010A - Antenna device and ic card with the same - Google Patents

Abstract

To provide an antenna device in which a communication characteristic is improved.SOLUTION: An antenna device comprises an antenna coil AC composed of a conductive pattern having a plurality of turns provided on one front surface 31 of a base material 30. If each turn of the antenna coil AC is defined by setting an external peripheral end 70 of the antenna coil AC as a start point, each turn includes: a first end part 71 as an external peripheral end of the turn; a second end part 72 as an internal peripheral end of the turn; and a transition point 73 that is positioned between the first end part 71 and the second end part 72. Each turn includes: a revolving section 81 that is positioned between the first end part 71 and the transition point 73 and is extended in a peripheral direction; and a transition section 82 that is positioned between the second end part 72 and the transition point 73. The transition point 73 is separated from a coil axis of the antenna coil AC more than the first end part 71, and the second end part 72 is connected to the first end part 71 of the turn adjacent on an inner peripheral side.SELECTED DRAWING: Figure 7

Description

The present disclosure relates to an antenna device and an IC card including the same.

Patent Document 1 discloses an IC card provided with an antenna device. The IC card described in Patent Document 1 can perform good communication with a card reader even when the main body is made of a metal plate.

JP 2020-195050 A

An object of the present disclosure is to provide an antenna device with improved communication characteristics and an IC card including the same.

An antenna device according to an embodiment of the present disclosure includes a base material and a first coil formed of a conductor pattern of multiple turns provided on one surface of the base material. When each turn of the coil is defined, each turn has a first end that is the outer peripheral end of the turn, a second end that is the inner peripheral end of the turn, and a first end and a second end. a transition point located between the turns, each turn being located between the first end and the transition point and extending in the circumferential direction; and being located between the second end and the transition point. a transition section, the transition point being further from the coil axis of the first coil than the first end, and the second end being connected to the first end of the inner circumferentially adjacent turn. .

According to the present disclosure, it is possible to provide an antenna device with improved communication characteristics.

FIG. 1 is a schematic perspective view showing the appearance of an IC card 1 incorporating an antenna device according to an embodiment of the present disclosure. FIG. 2 is a substantially see-through perspective view of the IC card 1 as seen from the rear surface b side. FIG. 3 is a schematic exploded perspective view of the IC card 1. FIG. FIG. 4 is a schematic plan view showing the pattern shape of the conductor pattern formed on one surface 31 of the base material 30. As shown in FIG. FIG. 5 is a schematic perspective plan view of the pattern shape of the conductor pattern formed on the other surface 32 of the base material 30 as seen from the one surface 31 side. FIG. 6 is a schematic perspective plan view showing a state in which the conductor pattern formed on one surface 31 of the base material 30 and the conductor pattern formed on the other surface 32 of the base material 30 are superimposed. FIG. 7 is an enlarged view for explaining the shape of the antenna coil AC. FIG. 8 is a schematic perspective view of the IC module 50 viewed from the back side. FIG. 9 is an equivalent circuit diagram of the IC card 1. As shown in FIG.

Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic perspective view showing the appearance of an IC card 1 incorporating an antenna device according to an embodiment of the present disclosure.

The IC card 1 shown in FIG. 1 is a plate-like body having a lateral direction in the y direction, which is the first direction, a longitudinal direction in the x direction, which is the second direction, and a thickness direction in the z direction, and constitutes an xy plane. It has a top surface a and a back surface b. The IC card 1 incorporates an IC module and an antenna device, which will be described later, and terminal electrodes E of the IC module are exposed on the upper surface a of the IC card 1 . The IC card 1 can communicate via the antenna device by facing the back surface b of the IC card 1 to the card reader 4 .

FIG. 2 is a schematic see-through perspective view of the IC card 1 as seen from the rear surface b side, and FIG. 3 is a schematic exploded perspective view of the IC card 1. As shown in FIG.

As shown in FIGS. 2 and 3, the IC card 1 has a structure in which a metal plate 10, a magnetic sheet 20, a base material 30 and a cover layer 40 are laminated in this order from the top surface a to the back surface b. ing. The metal plate 10 is made of a metal material such as stainless steel or titanium, and one surface thereof constitutes the upper surface a of the IC card 1 . An opening 11 is provided in the metal plate 10 and an IC module 50 is arranged inside the opening 11 .

The base material 30 is a film made of an insulating resin material such as PET, and forms an antenna device by forming conductor patterns on both sides of the base material 30 . Although the thickness of the base material 30 is not particularly limited, it can be about 20 to 30 μm.

FIG. 4 is a schematic plan view showing the pattern shape of the conductor pattern formed on one surface 31 of the base material 30. As shown in FIG. 5 is a schematic perspective plan view of the pattern shape of the conductor pattern formed on the other surface 32 of the base material 30, viewed from the one surface 31 side. Furthermore, FIG. 6 is a schematic perspective plan view showing a state in which the conductor pattern formed on one surface 31 of the base material 30 and the conductor pattern formed on the other surface 32 of the base material 30 are superimposed.

As shown in FIG. 4, the conductor pattern provided on one surface 31 of the base material 30 includes an antenna coil AC as a first coil, a first capacitor electrode pattern P11, and a connection pattern 110. As shown in FIG. The antenna coil AC is a loop antenna that is spirally wound, for example, 11 turns along the sides of a rectangular substrate 30 . As described above, since the antenna coil AC is provided along the sides of the base material 30, most of the base material 30 constitutes the opening area of the antenna coil AC.

An outer peripheral end of the antenna coil AC is connected to the connection node 91 . On the other hand, the inner peripheral end of antenna coil AC is connected to connection node 93 via connection pattern 110 . A first capacitor electrode pattern P11 is connected to the connection pattern 110 .

As shown in FIG. 5, the conductor pattern provided on the other surface 32 of the base material 30 includes a coupling coil CC1 as a second coil, a second capacitor electrode pattern P12, and a connection pattern 100. As shown in FIG. The coupling coil CC1 is spirally wound, for example, by eight turns, and has an inductance value smaller than that of the antenna coil AC. However, it is not essential that the coupling coil CC1 has a plurality of turns, and it may be looped with only one turn.

The outer peripheral end of the coupling coil CC1 is connected to the connection node 90 via the connection pattern 100. As shown in FIG. A second capacitor electrode pattern P12 is connected to the connection pattern 100 . The second capacitor electrode pattern P12 is provided at a position overlapping the first capacitor electrode pattern P11 in plan view. The connection node 90 is connected to a connection node 91 provided on one surface 31 of the substrate 30 via a through-hole conductor T11 provided through the substrate 30 . As a result, the outer peripheral end of the antenna coil AC and the outer peripheral end of the coupling coil CC1 are short-circuited. On the other hand, the inner peripheral end of the coupling coil CC1 is connected to the connection node 92 . The connection node 92 is connected to a connection node 93 provided on one surface 31 of the substrate 30 via a through-hole conductor T12 provided through the substrate 30 . As a result, the inner peripheral end of the antenna coil AC and the inner peripheral end of the coupling coil CC1 are short-circuited.

With such a configuration, the antenna coil AC and the coupling coil CC1 are connected in parallel, and a matching capacitor MC composed of the first and second capacitor electrode patterns P11 and P12 is inserted in parallel at the connecting portion. Thus, the antenna coil AC and the coupling coil CC1 do not have external terminals for direct-current connection, and are completely closed circuits in terms of direct current.

FIG. 7 is an enlarged view for explaining the shape of the antenna coil AC.

As shown in FIG. 7, of the conductor pattern forming the antenna coil AC, a section along the side 33 of the base material 30 extending in the y direction has a portion bent in the x direction. More specifically, when each turn of the antenna coil AC is defined with the outer peripheral edge 70 of the antenna coil AC as a starting point, each turn includes a first end 71 that is the outer peripheral edge of the turn and an inner peripheral edge of the turn. It has a second end 72 which is an edge and a transition point 73 located between the first end 71 and the second end 72 . Each turn includes a circumferential section 81 positioned between the first end 71 and the transition point 73 and extending in the circumferential direction, and a transition section 82 positioned between the second end 72 and the transition point 73. have

As shown in FIG. 4 , the circumferential section 81 extends in the y-direction along the side 33 of the base material 30 and is positioned between the first end 71 and the first corner 61; a second section S2 extending in the x-direction along the side 34 of the base material 30 and positioned between the first corner portion 61 and the second corner portion 62; a third section S3 extending between the second corner portion 62 and the third corner portion 63; A fourth section S4 positioned between the corner portions 64 and a fifth section S5 extending in the y-direction along the side 33 of the base material 30 and positioned between the fourth corner portion 64 and the transition point 73. include. On the other hand, the transition section 82 extends in the x-direction as shown in FIG.

Here, the transition point 73 is located radially outward of the first end 71 of the turn, and the transition section 82 extends radially inward from the transition point 73 toward the second end 72 . By being present, the second end 72 is connected to the first end 71 of the adjacent turn on the inner peripheral side. With such a configuration, the area of the opening region of the antenna coil AC is sufficiently secured while securing the distance between the outer peripheral end 70 of the antenna coil AC and the first section S1 of the outermost peripheral turn connected thereto and the side 33 of the base material 30. be able to. The outer edge 70 of the antenna coil AC and the first section S1 of the outermost turn are susceptible to the influence of the metal plate 10, which may cause deterioration in communication characteristics. However, in the present embodiment, the outer peripheral end 70 of the antenna coil AC and the first section S1 of the outermost turn are arranged such that the distance from the side 33 of the base material 30 is greater than that of the fifth section S5 of the outermost turn. Due to the design, the influence of the metal plate 10 is reduced, and good communication characteristics can be obtained. Such an effect becomes remarkable by setting the distance in the x direction between the first end portion 71 and the transition point 73 to be greater than or equal to the space between adjacent turns.

Also, the first and second capacitor electrode patterns P11 and P12 are arranged along the fifth section S5 of the innermost turn of the antenna coil AC. As a result, the wiring length of the connection patterns 100 and 110 can be shortened, and compared to the case where the first and second capacitor electrode patterns P11 and P12 are arranged along the first section S1 of the innermost peripheral turn, Since the distance in the x-direction from the innermost peripheral turn is ensured, the generation of eddy current due to the application of the magnetic flux to the first and second capacitor electrode patterns P11 and P12 is suppressed. Furthermore, as shown in FIG. 7, in the connection pattern 100, the pattern width of a section 101 that traverses the antenna coil AC in the radial direction when viewed from the z direction, which is the axial direction, is the same as that of a section 102 that overlaps the opening region of the antenna coil AC. It is designed to be narrower than the pattern width. As a result, the stray capacitance generated between the connection pattern 100 and the antenna coil AC is reduced, thereby suppressing deterioration in communication characteristics caused by the stray capacitance.

Here, the coupling coil CC1 is arranged at a position overlapping the opening 11 of the metal plate 10 so as to overlap the IC module 50 . Since the opening 11 of the metal plate 10 is offset in the -x direction of the base material 30, that is, in one short side, the coupling coil CC1 is similarly offset. Since the matching capacitor MC including the first and second capacitor electrode patterns P11 and P12 is also arranged in the vicinity of the coupling coil CC1, it is arranged offset to one short side of the substrate 30 .

As shown in FIG. 3, the magnetic sheet 20 is placed between the metal plate 10 and the substrate 30 and directly formed on the surface of the substrate 30 . The material of the magnetic sheet 20 is not particularly limited as long as it has a high magnetic permeability, but it may be a bulk body made of ferrite, metal magnetic material, etc., or a mixture of resin material and ferrite powder or metal magnetic powder. It may be made of a composite magnetic material. When a composite magnetic material is used, a mixture of an uncured resin material and ferrite powder or metal magnetic powder is applied to the surface of the base material 30, and then the resin material is cured to form the composite magnetic material on the surface of the base material 30. magnetic sheet 20 can be formed directly. The planar size of the magnetic sheet 20 is slightly larger than the external shape of the antenna coil AC, thereby functioning as a magnetic path for magnetic flux interlinking with the antenna coil AC. Since the IC card 1 has a metal plate 10 made of a metal material, communication becomes difficult if the metal plate 10 and the base material 30 are placed directly on top of each other. becomes.

Further, the magnetic sheet 20 is provided with an opening 21 at a position overlapping with the coupling coil CC1. As a result, the coupling coil CC1 and the IC module 50 directly face each other without the magnetic sheet 20 interposed therebetween.

FIG. 8 is a schematic perspective view of the IC module 50 viewed from the back side.

As shown in FIG. 8, the IC module 50 includes a module substrate 51 and an IC chip 52 mounted on or built into it. Terminal electrodes E shown in FIG. 1 are provided on the surface side of the module substrate 51 . The opening area and outer size of the coupling coil CC2 are substantially the same as the opening area and outer size of the coupling coil CC1 provided on the base material 30, so that electromagnetic field coupling occurs when the two are overlapped. This makes it possible to alternately connect the IC module 50 and the antenna coil AC via the coupling coils CC1 and CC2 without directly connecting the IC module 50 and the antenna coil AC using terminal electrodes.

FIG. 9 is an equivalent circuit diagram of the IC card 1. As shown in FIG.

As shown in FIG. 9, one end of the antenna coil AC is connected to one end of the coupling coil CC1, the other end of the antenna coil AC is connected to the other end of the coupling coil CC1, and a matching capacitor MC is connected to these connection points. are connected in parallel to form the main antenna ANT1. That is, the antenna coil AC, the coupling coil CC1 and the matching capacitor MC are connected in parallel with each other. An antenna coil AC included in the main antenna ANT1 communicates with the card reader 4 shown in FIG. A coupling coil CC1 included in the main antenna ANT1 is electromagnetically coupled with a coupling coil CC2 included in the IC module 50 . The coupling coil CC2 is connected in parallel to the input capacitor C1, and one end of the input capacitor C1 is connected to the input terminal of the IC chip 52.

Here, in the circuit configuration shown in FIG. 9, the antenna coil AC overlaps the magnetic sheet 20, the coupling coil CC1 does not overlap the magnetic sheet 20, and the inductance value of the coupling coil CC1 is the inductance value of the antenna coil AC. , the antenna characteristics are dominated by the inductance value of the coupling coil CC1, and even if the inductance value of the antenna coil AC varies somewhat, the antenna characteristics hardly change. Since the antenna device according to the present embodiment satisfies the above conditions, the inductance value of the antenna coil AC varies due to variations in the thickness and magnetic permeability of the magnetic sheet 20, the distance between the magnetic sheet 20 and the antenna coil AC, and the like. Even if , the inductance value of the coupling coil CC1 is dominant, the inductance value of the entire antenna device hardly varies, and stable antenna characteristics can be obtained. In addition, although the main factor of variation in the inductance value of the coil is variation in the thickness and magnetic permeability of the magnetic sheet 20, as described above, since the inductance value of the entire antenna device hardly changes, the frequency characteristics are stable, A highly reliable antenna device can be realized.

Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present disclosure. Needless to say, it is included within the scope.

For example, in the above embodiment, the antenna coil AC and the coupling coil CC1 are formed on the front and back of the substrate 30, but they may be formed on the same surface of the substrate 30. In the above embodiment, the connection pattern 100 is used to connect the outer peripheral end of the antenna coil AC and the outer peripheral end of the coupling coil CC1. It doesn't matter if you connect.

The technology according to the present disclosure includes, but is not limited to, the following configuration examples.

An antenna device according to the present disclosure includes a base material and a first coil formed of a conductor pattern of multiple turns provided on one surface of the base material. , each turn has a first end that is the outer peripheral end of the turn, a second end that is the inner peripheral end of the turn, and a position between the first end and the second end. each turn having a circumferentially extending circumferential section located between the first end and the transition point; and a transition section located between the second end and the transition point. The transition point is further from the coil axis of the first coil than the first end, and the second end is connected to the first end of the inner circumferentially adjacent turn. According to this, it is possible to provide an antenna device with improved communication characteristics.

The winding section extends in a first direction and extends between the first end and the first corner, and extends in the second direction and extends between the first corner and the second corner. a third section extending in the first direction and located between the second corner portion and the third corner portion; and extending in the second direction and extending between the third corner portion and the fourth A fourth section positioned between the corners and a fifth section extending in the first direction and positioned between the fourth corner and the transition point may be included. According to this, it is possible to sufficiently secure the opening area of the first coil.

The transition section may extend in the second direction. According to this, the opening area of the first coil can be more sufficiently secured, and the pattern design is facilitated.

An antenna device according to the present disclosure includes a first capacitor electrode pattern provided on one surface of a substrate and arranged in an opening region of a first coil, and a first capacitor electrode pattern provided on the other surface of the substrate and arranged in an opening region of a first coil. and a second capacitor electrode pattern overlapping with the first capacitor electrode pattern, and the first capacitor electrode pattern may be arranged along the fifth section of the innermost peripheral turn of the first coil. According to this, since the distance between the innermost peripheral turn of the first coil and the first and second capacitor electrode patterns is ensured, the occurrence of eddy current is suppressed.

The distance between the first end and the transition point in the direction perpendicular to the coil axis may be greater than or equal to the space between adjacent turns. According to this, it becomes possible to improve communication characteristics more significantly.

An antenna device according to the present disclosure includes a second coil provided on one or the other surface of a substrate and disposed within an opening region of the first coil when viewed from the axial direction, and provided on the other surface of the substrate, A connection pattern for connecting the outer peripheral end of the first coil and the outer peripheral end or the inner peripheral end of the second coil is further provided, and in the connection pattern, the first coil is arranged in a direction perpendicular to the coil axis when viewed from the axial direction. The pattern width of the crossing section may be narrower than the pattern width of the section overlapping the opening region of the first coil. This reduces the stray capacitance generated between the connection pattern and the first coil.

An antenna device according to the present disclosure includes: a second coil provided on one or the other surface of a substrate and disposed within an opening region of the first coil when viewed from the axial direction; and a magnetic sheet axially overlapping the first coil. The first coil, the second coil, and the capacitor composed of the first and second capacitor electrode patterns are connected in parallel with each other, and the magnetic sheet has an opening in a portion overlapping the second coil in the axial direction. and the inductance value of the second coil may be smaller than the inductance value of the first coil. This makes it possible to obtain stable antenna characteristics.

Also, the distance between the first end and the transition point in the direction perpendicular to the coil axis may be equal to or greater than the space between adjacent turns. According to this, it becomes possible to improve communication characteristics more significantly.

Further, the antenna device according to the present disclosure further includes a connection pattern provided on the other surface of the base material and connecting the outer peripheral end of the first coil and the outer peripheral end or the inner peripheral end of the second coil, wherein the connection pattern includes: The pattern width of the section crossing the first coil in the direction perpendicular to the coil axis when viewed in the axial direction may be narrower than the pattern width of the section overlapping the opening region of the first coil. This reduces the stray capacitance generated between the connection pattern and the first coil.

An IC card according to the present disclosure includes the above antenna device, a metal plate overlapping the antenna device, and an IC module. According to this, it is possible to provide an IC card having an antenna device with improved communication characteristics.

1 IC card 4 card reader 10 metal plates 11, 21 opening 20 magnetic sheet 30 base material 31 one surface of base material 32 other surface of base material 33 to 36 side of base material 40 cover layer 50 IC module 51 module substrate 52 IC chip 61 First corner portion 62 Second corner portion 63 Third corner portion 64 Fourth corner portion 70 Outer peripheral edge 71 First edge 72 Second edge 73 Transition point 81 Round section 82 Transition section 90-93 Connection node 100, 110 Connection patterns 101, 102 Section AC Antenna coil ANT1 Main antenna C1 Input capacitors CC1, CC2 Coupling coil E Terminal electrodes MC Matching capacitors P11, P12 Capacitor electrode pattern S1 First section S2 Second section S3 Third section S4 Fourth section S5 Fifth section T11, T12 Through-hole conductor a Top surface of IC card b Back surface of IC card

Claims (10)

a substrate;
A first coil made of a multi-turn conductor pattern provided on one surface of the base material,
When each turn of the first coil is defined with the outer peripheral end of the first coil as a starting point, each turn includes a first end that is the outer peripheral end of the turn and a second end that is the inner peripheral end of the turn. having an end and a transition point located between said first end and said second end;
Each turn has a circumferentially extending circumferential section located between the first end and the transition point, and a transition section located between the second end and the transition point. ,
the transition point is further from the coil axis of the first coil than the first end;
The antenna device, wherein the second end is connected to the first end of the turn adjacent to the inner peripheral side. The winding section includes a first section extending in a first direction and positioned between the first end and a first corner, and a first section extending in a second direction and being positioned between the first corner and the second corner. a second section positioned between the corners; a third section extending in the first direction and positioned between the second corner portion and the third corner portion; comprising a fourth section positioned between a third corner portion and a fourth corner portion; and a fifth section extending in the first direction and positioned between the fourth corner portion and the transition point. Item 1. The antenna device according to item 1. 3. The antenna device according to claim 2, wherein said transition section extends in said second direction. a first capacitor electrode pattern provided on the one surface of the base material and arranged in an opening region of the first coil;
a second capacitor electrode pattern provided on the other surface of the base material and overlapping the first capacitor electrode pattern;
4. The antenna device according to claim 2, wherein said first capacitor electrode pattern is arranged along said fifth section of the innermost peripheral turn of said first coil. 5. The antenna device according to claim 1, wherein a distance between said first end and said transition point in a direction perpendicular to said coil axis is greater than or equal to a space between adjacent turns. a second coil provided on the one or the other surface of the base material and disposed within an opening region of the first coil when viewed from the axial direction;
a connection pattern that is provided on the other surface of the base material and connects the outer peripheral end of the first coil and the outer peripheral end or the inner peripheral end of the second coil,
In the connection pattern, the pattern width of the section that crosses the first coil in the direction perpendicular to the coil axis when viewed from the axial direction is narrower than the pattern width of the section that overlaps the opening region of the first coil. The antenna device according to any one of claims 1 to 5. a second coil provided on the one or the other surface of the base material and disposed within an opening region of the first coil when viewed from the axial direction;
further comprising a magnetic sheet axially overlapping the first coil,
the first coil, the second coil, and the capacitor composed of the first and second capacitor electrode patterns are connected in parallel to each other;
The magnetic sheet has an opening in a portion overlapping the second coil in the axial direction,
5. The antenna device according to claim 4, wherein the inductance value of said second coil is smaller than the inductance value of said first coil. 8. The antenna device according to claim 7, wherein a distance between said first end and said transition point in a direction perpendicular to said coil axis is equal to or greater than a space between adjacent turns. further comprising a connection pattern provided on the other surface of the base material and connecting the outer peripheral end of the first coil and the outer peripheral end or the inner peripheral end of the second coil;
In the connection pattern, the pattern width of the section that crosses the first coil in the direction perpendicular to the coil axis when viewed from the axial direction is narrower than the pattern width of the section that overlaps the opening region of the first coil. The antenna device according to claim 7 or 8. An antenna device according to any one of claims 1 to 9;
a metal plate overlapping the antenna device;
An IC card, comprising an IC module.

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