Antenna device and IC card equipped with the same

Abstract

To reduce the size of a through hole provided in a metal plate in an antenna device applicable to an IC card.SOLUTION: An antenna device 1 includes a metal plate having a first through hole 43, a first coil pattern 110 whose opening 110a overlaps with the first through hole 43 and that winds around along the first through hole 43, and a second coil pattern 120 connected to the first coil pattern 110 and winding around along an outer edge 49 of a metal plate 40. The first through hole 43 has a first edge 431 located in a +Y direction as viewed from the center of the first through hole 43, and a second edge 432 located in a -Y direction as viewed from the center of the first through hole 43. The first and second edges 431 and 432 have first and second protruding portions 431A and 432A, respectively, that protrude toward the center of the first through hole 43 and have tips that overlap with the winding region of the first coil pattern 110.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present disclosure relates to an antenna device and an IC card including the same.

Background Art

[0002] Patent Document 1 discloses an IC card including a metal plate provided with a through hole and an IC module housed in the through hole.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the IC card described in Patent Document 1, since the IC module is mounted on the stepped portion of the metal plate provided around the through hole, there is a problem that the communication characteristics deteriorate due to the influence of the stepped portion.

[0005] In the present disclosure, a technique for suppressing deterioration of communication characteristics due to a metal plate is described in an antenna device applicable to an IC card.

Means for Solving the Problems

[0006] An antenna device according to an embodiment of the present disclosure includes a metal plate having a first through hole, a first coil having an opening overlapping the first through hole and circulating along the first through hole, and a coil including a second coil connected to the first coil and circulating along the outer edge of the metal plate. An edge of the first through hole has a first edge located on one side in a first direction when viewed from the center of the first through hole and a second edge located on the other side in the first direction when viewed from the center of the first through hole. The first edge has a first protrusion that protrudes toward the second edge and has a portion overlapping the winding region of the first coil. The second edge has a second protrusion that protrudes toward the first edge and has a portion overlapping the winding region of the first coil.

Effect of the Invention

[0007] According to the present disclosure, in an antenna device applicable to an IC card, a technique for suppressing a decrease in communication characteristics due to a metal plate is provided.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

MODE FOR CARRYING OUT THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0010] FIG. 1 is a schematic perspective view showing the appearance of an IC card 3 including an antenna device according to an embodiment of the present disclosure.

[0011] As shown in FIG. 1, the IC card 3 according to the present embodiment is a plate-like body having a longitudinal direction in the Y direction, a short side direction in the X direction, and a thickness direction in the Z direction, and has an upper surface 3a and a back surface 3b that constitute the XY plane. An IC module described later is built in the IC card 3, and the terminal electrode E of the IC module is exposed on the upper surface 3a of the IC card 3.

[0012] FIGS. 2 and 3 are a schematic exploded perspective view and a schematic cross-sectional view for explaining the structure of the IC card 3 including the antenna device 1 according to the present embodiment, respectively.

[0013] As shown in FIGS. 2 and 3, the IC card 3 has a structure in which a plastic plate 10, a film-like base material 20, a coil including a first coil pattern 110 and a second coil pattern 120 supported by the base material 20, a magnetic body 30, a metal plate 40, and a protective sheet 50 are laminated in this order from the back surface 3b side to the front surface 3a side. The antenna device 1 according to the present embodiment is composed of a first coil pattern 110, a second coil pattern 120, and a metal plate 40. The plastic plate 10, the base material 20, and the first coil pattern 110 and the second coil pattern 120 supported by the base material 20 are adhered via an adhesive layer 61. The base material 20 and the magnetic body 30 are adhered via an adhesive layer 62. The magnetic body 30 and the metal plate 40 are adhered via an adhesive layer 63. The metal plate 40 and the protective sheet 50 are adhered via an adhesive layer 64. Examples of the materials for the adhesive layers 61 to 64 include acrylic double-sided tape, thermosetting resin, and thermoplastic resin.

[0014] The plastic plate 10 is made of a resin material that does not obstruct magnetic flux. The outer surface of the plastic plate 10 constitutes the back surface 3b of the IC card 3.

[0015] The base material 20 is a film made of an insulating resin material, and conductor patterns are formed on both surfaces 21 and 22 thereof. The conductor patterns provided on the surface 21 of the base material 20 include a first coil pattern 110 and a second coil pattern 120. Examples of the conductive material constituting the conductor pattern include copper, aluminum, or alloys thereof. Examples of the insulating resin material constituting the base material 20 include PET (polyethylene terephthalate) and PI (polyimide). In the example shown in FIG. 3, the surface 21 of the base material 20 faces the plastic plate 10 side, and the surface 22 of the base material 20 faces the magnetic body 30 and the metal plate 40 side, but the front and back of the base material 20 may be reversed.

[0016] The magnetic body 30 is made of a high magnetic permeability material. The magnetic body 30 may be a sheet-like member or may be applied to the surface 22 of the base material 20. When the magnetic body 30 is a sheet-like member, the magnetic body 30 and the base material 20 are adhered to each other via an adhesive layer 62 as shown in FIG. 3. When the magnetic body 30 is applied to the surface 22 of the base material 20, the magnetic body 30 and the base material 20 are in direct contact without an adhesive layer in between. The magnetic body 30 is provided with a second through hole 31.

[0017] The metal plate 40 is made of a metal material such as stainless steel or titanium. On one surface 41 side of the metal plate 40, the plastic plate 10, the base material 20, the first coil pattern 110 and the second coil pattern 120 formed on its surface, and the magnetic body 30 are arranged. On the other surface 42 side of the metal plate 40, the protective sheet 50 and the IC module 70 are arranged. The metal plate 40 is provided with a first through hole 43 at a position overlapping the second through hole 31 of the magnetic body 30. The entire first through hole 43 may overlap the second through hole 31. Thus, the IC card 3 is a card in which the metal plate 40 is used as a part of the main body.

[0018] The protective sheet 50 is made of a material such as resin, and its outer surface constitutes the upper surface 3a of the IC card 3. The protective sheet 50 is provided with a third through-hole 51 at a position overlapping the first through-hole 43 of the metal plate 40. The entire first through-hole 43 may overlap the third through-hole 51. The IC module 70 is disposed inside the third through-hole 51. A part of the IC module 70 overlaps the metal plate 40, and the remaining part of the IC module 70 overlaps the first through-hole 43 of the metal plate 40. Thereby, the IC module 70 and the first coil pattern 110 face each other through the first through-hole 43. The surfaces 41, 42 of the metal plate 40 may be flat. For example, among the surfaces 42 of the metal plate 40, the region overlapping the IC module 70 and the region not overlapping the IC module 70 constitute the same plane. That is, there is no step or the like provided between the region of the surface 42 of the metal plate 40 that overlaps the IC module 70 and the region that does not overlap the IC module 70. Therefore, complicated processing is not required in manufacturing the metal plate 40.

[0019] FIG. 4 is a schematic plan view for explaining the shape of the metal plate 40.

[0020] As shown in FIG. 4, the first through-hole 43 provided in the metal plate 40 has a first edge 431 located in the +Y direction (one side in the Y direction) when viewed from the center of the first through-hole 43, a second edge 432 located in the -Y direction (the other side in the Y direction) which is opposite to the +Y direction when viewed from the center of the first through-hole 43, a third edge 433 located in the +X direction (one side in the X direction) intersecting the +Y direction when viewed from the center of the first through-hole 43, and a fourth edge 434 located in the -X direction (the other side in the X direction) which is opposite to the +X direction when viewed from the center of the first through-hole 43.

[0021] The first edge 431 does not have a linear shape in the X direction, but has a first protruding portion 431A that protrudes in the -Y direction toward the center of the first through hole 43 or the second edge 432. The tip of the first protruding portion 431A extends in the X direction. The second edge 432 does not have a linear shape in the X direction, but has a second protruding portion 432A that protrudes in the +Y direction toward the center of the first through hole 43 or the first edge 431. The tip of the second protruding portion 432A extends in the X direction. The third edge 433 does not have a linear shape in the Y direction, but has a third protruding portion 433A that protrudes in the -X direction toward the center of the first through hole 43 or the fourth edge 434. The tip of the third protruding portion 433A extends in the Y direction. The fourth edge 434 does not have a linear shape in the Y direction, but has a fourth protruding portion 434A that protrudes in the +X direction toward the center of the first through hole 43 or the third edge 433. The tip of the fourth protruding portion 434A extends in the Y direction.

[0022] At the corner 45 formed by the first edge 431 and the third edge 433, the first protruding portion 431A and the third protruding portion 433A are not provided. At the corner 46 formed by the first edge 431 and the fourth edge 434, the first protruding portion 431A and the fourth protruding portion 434A are not provided. At the corner 47 formed by the second edge 432 and the third edge 433, the second protruding portion 432A and the third protruding portion 433A are not provided. At the corner 48 formed by the second edge 432 and the fourth edge 434, the second protruding portion 432A and the fourth protruding portion 434A are not provided.

[0023] As a result, the width W2 of the first through hole 43 in the Y direction is reduced at the portions where the first protruding portion 431A and the second protruding portion 432A are present, and the width W1 of the first through hole 43 in the X direction is reduced at the portions where the third protruding portion 433A and the fourth protruding portion 434A are present. In the example shown in FIG. 4, the width W2, which is the distance in the Y direction between the first protruding portion 431A and the second protruding portion 432A, is larger than the width W1, which is the distance in the X direction between the third protruding portion 433A and the fourth protruding portion 434A. Note that the planar shape of the first through hole 43 assuming that the first protruding portion 431A to the fourth protruding portion 434A do not exist is substantially rectangular.

[0024] In FIG. 4, the position of the IC module 70 is indicated by a dashed line. A part of the IC module 70 overlaps with the first to fourth protruding portions 431A to 434A in a plan view as viewed from the Z direction. That is, in the present embodiment, the planar size of the first through hole 43 is smaller than that of the IC module 70. Thus, the IC module 70 is supported on the surface 42 side of the metal plate 40 by the first to fourth protruding portions 431A to 434A without being inserted into the first through hole 43. The corner portions of the IC module 70 overlap with the corner portions 45 to 48 of the first through hole 43.

[0025] In the example shown in FIG. 4, the widths of the first protruding portion 431A and the second protruding portion 432A in the X direction exceed half of the widths of the first edge 431 and the second edge 432 in the X direction. Similarly, in the example shown in FIG. 4, the widths of the third protruding portion 433A and the fourth protruding portion 434A in the Y direction exceed half of the widths of the third edge 433 and the fourth edge 434 in the Y direction. According to this, it is possible to stably support the IC module 70 by the surface 42 of the metal plate 40.

[0026] Also, in the example shown in FIG. 4, the protruding amounts of the first protruding portion 431A and the second protruding portion 432A are larger than the protruding amounts of the third protruding portion 433A and the fourth protruding portion 434A. According to this, it is possible to more stably support the IC module 70 having the Y direction as the longitudinal direction.

[0027] The first protrusion 431A is disposed substantially at the center of the first edge 431 in the X direction, and the position of its tip in the Y direction does not overlap with the third protrusion 433A and the fourth protrusion 434A. The second protrusion 432A is disposed substantially at the center of the second edge 432 in the X direction, and the position of its tip in the Y direction does not overlap with the third protrusion 433A and the fourth protrusion 434A. The third protrusion 433A is disposed substantially at the center of the third edge 433 in the Y direction, and the position of its tip in the X direction does not overlap with the first protrusion 431A and the second protrusion 432A. The fourth protrusion 434A is disposed substantially at the center of the fourth edge 434 in the Y direction, and the position of its tip in the X direction does not overlap with the first protrusion 431A and the second protrusion 432A.

[0028] Thus, when assuming a virtual quadrangle along the tips of the first protrusion 431A, the second protrusion 432A, the third protrusion 433A, and the fourth protrusion 434A, the corners thereof are located at the corners 45 to 48 of the first through hole 43 where the protrusions 431A to 434A do not exist. In the example shown in FIG. 4, the planar shape of the first through hole 43 is point-symmetric with respect to the center of the first through hole 43. According to this, the IC module 70 can be stably supported by the first protrusion 431A to the fourth protrusion 434A. Further, in the example shown in FIG. 4, the corners of the tips of the first protrusion 431A to the fourth protrusion 434A have a round shape. According to this, it is possible to suppress the electric field concentration at the corners of the tips of the first protrusion 431A to the fourth protrusion 434A and to prevent damage to the IC module 70 due to sharp corners.

[0029] In the example shown in FIG. 4, the first protrusion 431A to the fourth protrusion 434A are provided on the first edge 431 to the fourth edge 434, respectively, but it is not essential to provide protrusions on all edges, and some protrusions may be omitted. For example, the third protrusion 433A and the fourth protrusion 434A may be omitted, and only the first protrusion 431A and the second protrusion 432A may be provided. In this case, the third edge 433 and the fourth edge 434 extend substantially linearly in the Y direction.

[0030] FIG. 5 is a schematic plan view of a conductor pattern formed on one surface 21 of the base material 20.

[0031] In the example shown in FIG. 5, a first coil pattern 110, a second coil pattern 120, and capacitor patterns 131 and 133 are provided on one surface 21 of the base material 20. In FIG. 5, the position of the second through hole 31 provided in the magnetic body 30 is indicated by a broken line. The first coil pattern 110 is disposed at a position overlapping the second through hole 31 of the magnetic body 30. In the example shown in FIG. 5, the number of turns of the first coil pattern 110 is about 9 turns. The width of the first coil pattern 110 in the X direction is W6, and the width of the first coil pattern 110 in the Y direction is W7. The width W6 is smaller than the width W4 of the second through hole 31 in the X direction. The width W7 is smaller than the width W5 of the second through hole 31 in the Y direction. In the example shown in FIG. 5, the entire first coil pattern 110 overlaps the second through hole 31 of the magnetic body 30.

[0032] The second coil pattern 120 is a pattern that circulates about 3 turns along the outer edge of the base material 20, and the first coil pattern 110 and the capacitor patterns 131 and 133 are disposed in an opening 120a surrounded by the second coil pattern 120. The outer shape of the base material 20 and the outer shape of the metal plate 40 are substantially the same. Therefore, when the base material 20 and the metal plate 40 are overlapped, in plan view, the second coil pattern 120 will circulate along the outer edge 49 of the metal plate 40.

[0033] The capacitor pattern 131 is a pattern that branches in the X direction from the innermost turn of the second coil pattern 120. In the example shown in FIG. 5, seven capacitor patterns 131 branch from the innermost turn of the second coil pattern 120, but the number of capacitor patterns 131 is not particularly limited. Also, a plurality of capacitor patterns 133 branch from one capacitor pattern 131. All of the capacitor patterns 133 extend in the Y direction. In the example shown in FIG. 5, twelve capacitor patterns 133 branch from one capacitor pattern 131, but the number of capacitor patterns 133 is not particularly limited.

[0034] FIG. 6 is a schematic plan view of the conductor pattern formed on the other surface 22 of the base material 20, showing the state as viewed through the base material 20 from the one surface 21 side.

[0035] As shown in FIG. 6, capacitor patterns 132, 134 and connection patterns 141, 142 are arranged on the other surface 22 of the base material 20. The planar positions of the capacitor patterns 132, 134 respectively coincide with those of the capacitor patterns 131, 133. That is, the capacitor patterns 131, 132 face each other through the base material 20, and the capacitor patterns 133, 134 face each other through the base material 20. Thereby, the capacitor C is constituted by the capacitor patterns 131, 133 provided on one surface 21 of the base material 20, the capacitor patterns 132, 134 provided on the other surface 22 of the base material 20, and the base material 20 positioned therebetween. The capacitance of the capacitor C having such a pattern shape can be finely adjusted by removing some of the capacitor patterns 133 by trimming.

[0036] As shown in FIGS. 5 and 6, the outer peripheral end of the second coil pattern 120 is connected to the capacitor patterns 132 and 134 via a via conductor 151 provided through the base material 20. Also, a part of the second turn (the second turn counted from the innermost turn) among the turns constituting the second coil pattern 120 is divided. One and the other ends of the divided part are respectively connected to via conductors 152 and 153 provided through the base material 20. The via conductor 152 is connected to one end of the connection pattern 141, and the via conductor 153 is connected to one end of the connection pattern 142. The other ends of the connection patterns 141 and 142 are respectively connected to via conductors 154 and 155 provided through the base material 20. The via conductors 154 and 155 are respectively connected to the inner peripheral end and the outer peripheral end of the first coil pattern 110.

[0037] With such a configuration, the first coil pattern 110 and the second coil pattern 120 are connected in series, and as shown in FIG. 7, a capacitor C is connected in series to the first and second coil patterns 110 and 120. A resonance circuit composed of the first and second coil patterns 110 and 120 and the capacitor C forms a closed circuit not connected to an external circuit. The capacitor C plays a role of enhancing communication characteristics by adjusting the resonance frequency. Then, by setting the resonance frequency of this closed circuit to a frequency band of 13.56 MHz or near 13.56 MHz, short-range wireless communication (NFC) becomes possible. Alternatively, as shown in FIG. 8, the capacitor C may be connected in parallel to the first and second coil patterns 110 and 120. In this case, by designing such that the line length of the first coil pattern 110 is longer than the line length of the second coil pattern 120, it is possible to obtain resonance characteristics similar to those in the case where the capacitor C is connected in series to the first and second coil patterns 110 and 120.

[0038] FIG. 9 is a schematic plan view showing a state in which the base material 20, the magnetic body 30, and the metal plate 40 are stacked.

[0039] As shown in FIG. 9, when the base material 20, the magnetic body 30, and the metal plate 40 are stacked, the first coil pattern 110 provided on the base material 20, the second through hole 31 of the magnetic body 30, and the first through hole 43 of the metal plate 40 overlap in the Z direction. The opening 110a surrounded by the first coil pattern 110 also overlaps with the second through hole 31 and the first through hole 43. The width of the opening 110a in the X direction is W8, and the width of the opening 110a in the Y direction is W9. The width W8 is smaller than the widths W1 and W4 (see FIGS. 4 and 5), and the width W9 is smaller than the widths W2 and W5 (see FIGS. 4 and 5). That is, the area of the opening 110a is smaller than the areas of the through holes 31 and 43. The entire opening 110a of the first coil pattern 110 may overlap with the through holes 31 and 43. According to this, it is possible to prevent the interference between the magnetic flux passing through the opening 110a of the first coil pattern 110, the magnetic body 30, and the metal plate 40.

[0040] The width W6 (see FIG. 5) of the first coil pattern 110 in the X direction is larger than the width W1 (see FIG. 4) of the first through hole 43 of the metal plate 40 in the X direction. The width W7 (see FIG. 5) of the first coil pattern 110 in the Y direction is larger than the width W2 (see FIG. 4) of the first through hole 43 of the metal plate 40 in the Y direction. As a result, when the base material 20 and the metal plate 40 are stacked, the tips of the first protruding portions 431A to 434A of the first through hole 43 overlap with the winding region of the first coil pattern 110. The winding region of the first coil pattern 110 is a region located between the inner peripheral edge 111 and the outer peripheral edge 112 of the first coil pattern 110. As a result, in the first coil pattern 110, there are a portion that overlaps with the metal plate 40 and a portion that overlaps with the first through hole 43 without overlapping with the metal plate 40. The outer peripheral edge 112 of the first coil pattern 110 has a portion located between the edge of the second through hole 31 of the magnetic body 30 and the edge of the first through hole 43 of the metal plate 40. The winding region of the second coil pattern 120 is a region located between the inner peripheral edge 121 and the outer peripheral edge 122 of the second coil pattern 120.

[0041] In the example shown in Fig. 9, the tips of the first to fourth protruding portions 431A to 434A are located outside the center in the radial direction of the winding region of the first coil pattern 110. According to this, since the overlapping area between the winding region of the first coil pattern 110 and the metal plate 40 is reduced, it becomes possible to pass more magnetic flux through the first through hole 43. Further, since the magnetic flux density is low directly above and directly below the winding region of the first coil pattern 110 compared to the vicinity of the opening 110a and the outer peripheral edge 112, by arranging the edges 431 to 434 of the first through hole 43 in this region, it becomes possible to suppress the deterioration of the antenna characteristics due to the demagnetizing field.

[0042] In the example shown in Fig. 9, since the protruding amounts of the first and second protruding portions 431A and 432A are larger than the protruding amounts of the third and fourth protruding portions 433A and 434A, the tips of the first and second protruding portions 431A and 432A are located closer to the center in the radial direction of the winding region of the first coil pattern 110 than the tips of the third and fourth protruding portions 433A and 434A.

[0043] Fig. 10 is a schematic perspective view of the IC module 70 as seen from the back side.

[0044] As shown in FIG. 10, the IC module 70 includes a module substrate 71, an IC chip 72 mounted on or built into the module substrate 71, and a coupling coil 73. The IC chip 72 is protected by being covered with a dome-shaped protective resin 74. The protective resin 74 is made of an insulating member. When the IC module 70 is disposed on the surface 42 of the metal plate 40, as shown in FIG. 3, the coupling coil 73 and the adhesive layer 64 are adhered via a hot melt tape 75. In this state, a part of the protective resin 74 may be disposed within the first through hole 43 of the metal plate 40. On the back side of the module substrate 71, terminal electrodes E shown in FIG. 1 are provided. The IC module 70 having such a configuration is disposed on the other surface 42 side of the metal plate 40. As described above, although a part of the protective resin 74 may be disposed within the first through hole 43 of the metal plate 40, the module substrate 71 itself is not disposed within the first through hole 43 of the metal plate 40. Thereby, the size of the first through hole 43 of the metal plate 40 can be made smaller than the size of the module substrate 71.

[0045] When the IC module 70 is disposed on the other surface 42 side of the metal plate 40, the coupling coil 73 and the first coil pattern 110 provided on the base material 20 are electromagnetically coupled via the first through hole 43 of the metal plate 40. The planar position of the winding region of the coupling coil 73 may substantially coincide with the planar position of the winding region of the first coil pattern 110. In this case, the tips of the first protrusions 431A to 434A of the first through hole 43 of the metal plate 40 overlap the winding region of the coupling coil 73. Since the first coil pattern 110 is connected in series with the second coil pattern 120, when a current flows through the first coil pattern 110, a current also flows through the second coil pattern 120, and a magnetic field is generated from the second coil pattern 120. Thereby, as shown in FIG. 11, when the back surface 3b of the IC card 3 faces the card reader 6, communication can be performed between the card reader 6 and the IC chip 72.

[0046] In this embodiment, the number of turns of the first coil pattern 110 is about 9 turns, and the number of turns of the second coil pattern 120 is about 3 turns. The first coil pattern 110 has a greater number of turns than the second coil pattern 120. As a result, the coupling between the first coil pattern 110 and the coupling coil 73 of the IC module 70 is enhanced. On the other hand, for the second coil pattern 120, since the number of turns is smaller than that of the first coil pattern 110 and the pattern width is larger than the pattern width of the first coil pattern 110, the resistance value of the second coil pattern 120 is reduced.

[0047] As described above, the antenna device 1 according to this embodiment includes a metal plate 40 having a first through-hole 43. Since the first coil pattern 110 is arranged such that the opening 110a overlaps with the first through-hole 43 and circulates along the first through-hole 43, it is possible to connect the IC module 70 arranged on the other surface 42 of the metal plate 40 and the first coil pattern 110 arranged on one surface 41 of the metal plate 40. Moreover, since the first edge 431 to the fourth edge 434 of the first through-hole 43 each have a first protrusion 431A to a fourth protrusion 434A, the first protrusion 431A to the fourth protrusion 434A make it possible to support the IC module 70 having a planar size larger than that of the first through-hole 43 on the surface 42 of the metal plate 40. In addition, since the planar size of the first through-hole 43 is smaller than the planar size of the IC module 70, the strength of the metal plate 40 is also increased. Further, the corner portions of the IC module 70 overlap with the corner portions 45 to 48 of the first through-hole 43, and since the metal plate 40 does not support the peripheral edge of the IC module 70 over the entire circumference, the area of the metal plate 40 covering the region where the coupling coil 73 of the IC module 70 and the first coil pattern 110 of the antenna device 1 are coupled is reduced. Therefore, a decrease in the coupling between the coupling coil 73 of the IC module 70 and the first coil pattern 110 of the antenna device 1 can be suppressed. Thus, since the first edge 431 to the fourth edge 434 of the first through-hole 43 each have a first protrusion 431A to a fourth protrusion 434A, it is possible to suppress a decrease in communication characteristics due to the metal plate 40.

[0048] FIG. 12 is a schematic plan view for explaining the shape of the metal plate 40 according to the first modification.

[0049] The metal plate 40 shown in FIG. 12 is different from the metal plate 40 shown in FIG. 4 in that the width of the first protrusion 431A and the second protrusion 432A in the X direction is about 1 / 2 of the width of the first edge 431 and the second edge 432 in the X direction, and the width of the third protrusion 433A and the fourth protrusion 434A in the Y direction is about 1 / 2 of the width of the third edge 433 and the fourth edge 434 in the Y direction. Thus, if the widths of the first protrusion 431A to the fourth protrusion 434A are reduced, the area of the first through hole 43 is enlarged, so that more magnetic flux can pass through the first through hole 43.

[0050] FIG. 13 is a schematic plan view for explaining the shape of the metal plate 40 according to the second modification.

[0051] The metal plate 40 shown in FIG. 13 is different from the metal plate 40 shown in FIG. 4 in that the first protrusion 431A to the fourth protrusion 434A are all divided into a plurality of parts. Thus, a plurality of the first protrusions 431A to the fourth protrusions 434A may be provided on the first edge 431 to the fourth edge 434, respectively. According to this, while stably supporting the IC module 70, more magnetic flux can pass through the first through hole 43.

[0052] FIG. 14 is a schematic plan view for explaining the shape of the metal plate 40 according to the third modification.

[0053] The metal plate 40 shown in FIG. 14 is different from the metal plate 40 shown in FIG. 4 in that the first protruding portion 431A has the first connecting portion 81 and the first wide portion 91, the second protruding portion 432A has the second connecting portion 82 and the second wide portion 92, the third protruding portion 433A has the third connecting portion 83 and the third wide portion 93, and the fourth protruding portion 434A has the fourth connecting portion 84 and the fourth wide portion 94. The first connecting portion 81 to the fourth connecting portion 84 are portions connected to the main body portion of the metal plate 40. The first wide portion 91 to the fourth wide portion 94 are portions located closer to the center of the first through hole 43 than the first connecting portion 81 to the fourth connecting portion 84, respectively. That is, the first wide portion 91 is located on the -Y direction side of the first connecting portion 81, the second wide portion 92 is located on the +Y direction side of the second connecting portion 82, the third wide portion 93 is located on the -X direction side of the third connecting portion 83, and the fourth wide portion 94 is located on the +X direction side of the fourth connecting portion 84. In the example shown in FIG. 14, the first wide portion 91 to the fourth wide portion 94 constitute the tips of the first edge 431 to the fourth edge 434, respectively. And the width in the X direction of the first wide portion 91 and the second wide portion 92 is larger than the width in the X direction of the first connecting portion 81 and the second connecting portion 82. Similarly, the width in the Y direction of the third wide portion 93 and the fourth wide portion 94 is larger than the width in the Y direction of the third connecting portion 83 and the fourth connecting portion 84.

[0054] When the metal plate 40 having such a shape is used, the planar position of the outer peripheral edge of the first coil pattern 110 or the coupling coil 73 can be arranged so as to overlap the space located between the first wide portion 91 to the fourth wide portion 94 and the main body portion of the metal plate 40. According to this, since most of the outer peripheral edge of the first coil pattern 110 or the coupling coil 73 overlaps the first through hole 43 without overlapping the metal plate 40, it becomes possible to pass more magnetic flux through the first through hole 43.

[0055] As described above, the embodiments of the present disclosure have been described. However, the present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present disclosure, and it goes without saying that those are also included in the scope of the present disclosure.

[0056] For example, the conductor patterns provided on the surfaces 21 and 22 of the base material 20 may be provided on the surfaces 21 and 22 of the base material 20 via other material layers containing resin in between. Also, the coil may be formed by winding a conducting wire.

[0057] Further, the first coil pattern 110 and the second coil pattern 120 constituting the coil are not limited to the pattern shapes shown in FIG. 5. For example, each turn of the second coil pattern 120 may protrude toward the opening 120a, and a pattern in which the protruding portion is wound in a direction opposite to that of the second coil pattern 120 may be the first coil pattern 110. In this case, the first coil pattern 110 and the second coil pattern 120 can be formed on only one surface of the base material 20.

[0058] The technology according to the present disclosure includes, but is not limited to, the following configuration examples.

[0059] An antenna device according to an embodiment of the present disclosure includes a metal plate having a first through hole, a first coil whose opening overlaps the first through hole and that winds along the first through hole, and a coil including a second coil connected to the first coil and winding along the outer edge of the metal plate. The edge of the first through hole has a first edge located on one side in a first direction when viewed from the center of the first through hole and a second edge located on the other side in the first direction when viewed from the center of the first through hole. The first edge has a first protruding portion that protrudes toward the second edge and has a portion overlapping the winding region of the first coil. The second edge has a second protruding portion that protrudes toward the first edge and has a portion overlapping the winding region of the first coil. According to this, it becomes possible to support an IC module or the like on the surface of the metal plate, and it also becomes possible to suppress a decrease in communication characteristics due to the metal plate.

[0060] In the above antenna device, the planar shape of the first through-hole may be point-symmetrical with respect to the center of the first through-hole. According to this, it becomes possible to stably support an IC module or the like on the surface of the metal plate.

[0061] In the above antenna device, the tips of the first and second protrusions may be located outside the center in the radial direction of the winding region of the first coil. According to this, it becomes possible to reduce the area where the first coil and the metal plate overlap.

[0062] In the above antenna device, the first edge may have a plurality of first protrusions, and the second edge may have a plurality of second protrusions. According to this, while stably supporting an IC module or the like on the surface of the metal plate, it becomes possible to pass more magnetic flux through the first through-hole.

[0063] In the above antenna device, the corners of the tips of the first and second protrusions may have a round shape. According to this, it becomes possible to suppress the electric field concentration at the corners of the tips of the first and second protrusions.

[0064] In the above antenna device, the edge of the first through-hole has a third edge located on one side in a second direction intersecting the first direction as viewed from the center of the first through-hole, and a fourth edge located on the other side in the second direction as viewed from the center of the first through-hole. The third edge may have a third protrusion that protrudes toward the fourth edge and has a portion overlapping the winding region of the first coil, and the fourth edge may have a fourth protrusion that protrudes toward the third edge and has a portion overlapping the winding region of the first coil. According to this, it becomes possible to more stably support an IC module or the like on the surface of the metal plate.

[0065] In the above antenna device, the first edge may have a plurality of first protrusions, the second edge may have a plurality of second protrusions, the third edge may have a plurality of third protrusions, and the fourth edge may have a plurality of fourth protrusions. According to this, while stably supporting an IC module or the like on the surface of the metal plate, it becomes possible to pass more magnetic flux through the first through hole.

[0066] In the above antenna device, the first protrusion has a first connection portion and a first wide portion located on the other side in the first direction from the first connection portion, and the second protrusion has a second connection portion and a second wide portion located on one side in the first direction from the second connection portion. The width in the second direction intersecting the first direction of the first and second wide portions may be larger than the width in the second direction of the first and second connection portions. According to this, it becomes possible to reduce the overlap between the outer edge portion of the first coil and the metal plate.

[0067] In the above antenna device, the pattern width of the second coil may be larger than the pattern width of the first coil, and the number of turns of the second coil may be less than the number of turns of the first coil. According to this, the magnetic flux density generated by the first coil can be increased, and the resistance value of the second coil can be reduced.

[0068] The above antenna device further includes a magnetic body having a second through hole overlapping the first through hole. The area of the second through hole may be larger than the area of the first through hole, and the entire first through hole may overlap the second through hole. According to this, it becomes possible to eliminate the overlap between the first coil and the magnetic body.

[0069] An IC card according to an embodiment of the present disclosure includes any one of the above antenna devices and an IC module overlapping the first coil through the first through hole. According to this, it becomes possible to provide an IC card including a metal plate.

[0070] In the above IC card, the IC module has a coupling coil that overlaps with the first coil in a plan view, and the first and second protrusions may overlap with the winding region of the coupling coil. According to this, it is possible to arrange the edge of the first through hole of the metal plate in a region where the magnetic flux density is low.

[0071] In the above IC card, the first coil is arranged on one surface side of the metal plate, the IC module is arranged on the other surface side of the metal plate, the IC module has a module substrate, an IC chip mounted on the module, and a protective resin covering the IC chip, and at least a part of the protective resin may be located in the first through hole. According to this, it is possible to couple the IC module and the first coil without arranging the module substrate in the first through hole of the metal plate.

Explanation of Signs

[0072] 1 Antenna device 3 IC card 3a Upper surface of the IC card 3b Back surface of the IC card 6 Card reader 10 Plastic plate 20 Base material 21, 22 Surfaces of the base material 22 Surface 30 Magnetic body 31 Second through hole 40 Metal plate 41, 42 Surfaces of the metal plate 43 First through hole 45 - 48 Corners 49 Outer edge of the metal plate 50 Protective sheet 51 Third through hole 61 - 64 Adhesive layer 70 IC module 71 Module substrate 72 IC chip 73 Coupling coil 74 Protective resin 75 Hot melt tape 110 First coil pattern 110a Opening of the first coil pattern 111 Inner peripheral edge of the first coil pattern 112 Outer peripheral edge of the first coil pattern 120 Second coil pattern 120a Opening of the second coil pattern 121 Inner peripheral edge of the second coil pattern 122 Outer peripheral edge of the second coil pattern 131 - 134 Capacitor pattern 141, 142 Connection pattern 151 - 155 Via conductor 431 - 434 Edges of the first through - hole 431A - 434A Protrusion C Capacitor E Terminal electrode

Claims

1. A metal plate having a first through-hole, a coil including a first coil whose opening overlaps with the first through-hole and which winds along the first through-hole, and a second coil connected to the first coil and winding along the outer edge of the metal plate, comprising: The edge of the first through-hole has a first edge located on one side in a first direction when viewed from the center of the first through-hole, and a second edge located on the other side in the first direction when viewed from the center of the first through-hole, The first edge has a first protrusion that protrudes toward the second edge and has a portion overlapping with the winding region of the first coil, The second edge has a second protrusion that protrudes toward the first edge and has a portion overlapping with the winding region of the first coil, An antenna device.

2. The planar shape of the first through-hole is point-symmetric with respect to the center of the first through-hole, The antenna device according to Claim 1.

3. The tips of the first and second protrusions are located outside the center in the radial direction of the winding region of the first coil, The antenna device according to Claim 1.

4. The first edge has a plurality of the first protrusions, The second edge has a plurality of the second protrusions, The antenna device according to Claim 1.

5. The corners of the tips of the first and second protrusions have a round shape, The antenna device according to Claim 1.

6. The edge of the first through-hole has a third edge located on one side in a second direction intersecting the first direction when viewed from the center of the first through-hole, and a fourth edge located on the other side in the second direction when viewed from the center of the first through-hole, The third edge has a third protrusion that protrudes toward the fourth edge and has a portion overlapping with the winding region of the first coil, The fourth edge has a fourth protrusion that protrudes toward the third edge and has a portion overlapping with the winding region of the first coil, The antenna device according to Claim 1.

7. The first edge has a plurality of the first protrusions, The second edge has a plurality of the second protrusions, The third edge has a plurality of the third protrusions, The fourth edge has a plurality of the fourth protrusions, The antenna device according to Claim 6.

8. The first protrusion has a first connecting portion and a first wide portion located on the other side in the first direction than the first connecting portion, The second protruding portion has a second connecting portion and a second wide portion located on one side in the first direction with respect to the second connecting portion. The widths of the first and second wide portions in a second direction intersecting the first direction are larger than the widths of the first and second connecting portions in the second direction. The antenna device according to claim 1.

9. The pattern width of the second coil is larger than the pattern width of the first coil. The number of turns of the second coil is smaller than the number of turns of the first coil. The antenna device according to claim 1.

10. The antenna device further includes a magnetic body having a second through hole overlapping the first through hole. The area of the second through hole is larger than the area of the first through hole. The whole of the first through hole overlaps the second through hole. The antenna device according to claim 1.

11. An antenna device according to any one of claims 1 to 10, and an IC module overlapping the first coil through the first through hole. An IC card comprising the same.

12. The IC module has a coupling coil overlapping the first coil in a plan view. The first and second protruding portions overlap a winding region of the coupling coil. The IC card according to claim 11.

13. The first coil is disposed on one surface side of the metal plate. The IC module is disposed on the other surface side of the metal plate. The IC module has a module substrate, an IC chip mounted on the module, and a protective resin covering the IC chip. At least a part of the protective resin is located in the first through hole. The IC card according to claim 11.

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