Antenna module

Abstract

To provide an antenna module that can be produced by a simpler process.SOLUTION: An antenna module 1 comprises a substrate 30, a coil pattern CP that is disposed on one surface 31 of the substrate 30, and a magnetic substance 20 that covers the other surface 32 of the substrate 30 and includes a through-hole 21. The coil pattern CP has a first and a second coil interval, 100, 200. The second coil interval 200 is disposed within an opening of the first coil interval 100. The inner peripheral end of the first coil interval 100 is connected to the outer peripheral end of the second coil interval 200. The second coil interval 200 includes a first extension interval 210 that extends along the first coil interval 100, and a second extension interval 220 that projects toward the through-hole 21 from the first extension interval 210 in a plan view and turns in a direction opposite the first extension interval 210 while overlapping the through-hole 21.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to an antenna module.

Background Art

[0002] Patent Document 1 discloses an IC card having a wireless communication function. The IC card described in Patent Document 1 includes an antenna module including a magnetic body, an antenna coil overlapping the magnetic body, and a coupling coil overlapping a through hole of the magnetic body, and an IC module that electromagnetically couples with the coupling coil.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the antenna module described in Patent Document 1, the antenna coil is formed on one surface of the base material, and the coupling coil is formed on the other surface of the base material. Therefore, it is necessary to form conductor patterns on both surfaces of the base material and to provide via conductors for connecting the conductor patterns formed on both surfaces of the base material, and there is room for improvement from the viewpoint of the manufacturing process.

[0005] Therefore, an object of the present disclosure is to provide an antenna module that can be manufactured by a simpler process.

Means for Solving the Problems

[0006] An antenna module according to an embodiment of the present disclosure includes a base material, a coil pattern provided on one surface of the base material, and a magnetic body covering the other surface of the base material and having a through hole. The coil pattern has a first coil section and a second coil section. The second coil section is disposed within the opening of the first coil section. The inner peripheral end of the first coil section is connected to the outer peripheral end of the second coil section. The second coil section has a first extending section extending along the first coil section, and a second extending section that protrudes from the first extending section toward the through hole in a plan view and turns in a direction opposite to the first extending section while overlapping the through hole.

Advantages of the Invention

[0007] According to the present disclosure, it is possible to provide an antenna module that can be manufactured by a simpler process.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0009] Hereinafter, preferred 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 2 including an antenna module according to an embodiment of the present disclosure.

[0011] As shown in FIG. 1, the IC card 2 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 2a and a back surface 2b that constitute the XY plane. An IC module described later is built in the IC card 2, and the terminal electrodes E of the IC module are exposed on the upper surface 2a of the IC card 2. The IC card 2 can communicate by facing the back surface 2b to the card reader 4.

[0012] FIG. 2 is a schematic exploded perspective view for explaining the structure of an IC card 2 including an antenna module 1 according to an embodiment of the present disclosure.

[0013] The IC card 2 shown in FIG. 2 has a structure in which a metal plate 10, a magnetic body 20, a base material 30, and a cover layer 40 are laminated in this order from one surface 2a side to the other surface 2b side. The metal plate 10 is made of a metal material such as stainless steel or titanium, and its surface constitutes one surface 2a of the IC card 2. An opening 11 is provided in the metal plate 10, and an IC module 50 is disposed inside the opening 11.

[0014] The base material 30 is a film made of an insulating resin material such as PET (polyethylene terephthalate), and a coil pattern CP, which is a conductor pattern made of a good conductor such as Cu, is formed on one surface thereof. No conductor pattern is formed on the other surface of the base material 30, and no via conductor penetrating the base material 30 is provided. The other surface of the base material 30 is covered with the magnetic body 20. A through hole 21 is provided in the magnetic body 20. As the magnetic body 20, a material obtained by curing a paste-like member in which magnetic particles and a resin are mixed may be used, or a sheet-like member may be used. The antenna module 1 according to the present embodiment is composed of the base material 30, the conductor pattern formed on the surface thereof, and the magnetic body 20.

[0015] FIG. 3 is a schematic plan view showing the pattern shape of the coil pattern CP formed on one surface 31 of the base material 30. In FIG. 3, the through hole 21 of the magnetic body 20 located on the other surface 32 side of the base material 30 is indicated by a broken line.

[0016] As shown in FIG. 3, the coil pattern CP provided on one surface 31 of the base material 30 includes a first coil section 100 and a third coil section 300 that function as an antenna coil, and a second coil section 200 that functions as an antenna coil and a coupling coil. The first coil section 100, the second coil section 200, and the third coil section 300 are connected in series in this order from the outer peripheral end to the inner peripheral end of the coil pattern CP. That is, the inner peripheral end of the first coil section 100 is connected to the outer peripheral end of the second coil section 200, and the inner peripheral end of the second coil section 200 is connected to the outer peripheral end of the third coil section 300. As a result, the second coil section 200 is disposed within the opening of the first coil section 100, and the third coil section 300 is disposed within the opening of the second coil section 200.

[0017] Both ends of the coil pattern CP, that is, the outer peripheral end of the first coil section 100 and the inner peripheral end of the third coil section 300 are open. That is, the outer peripheral end of the first coil section 100 and the inner peripheral end of the third coil section 300 terminate without being connected to other conductor patterns or circuit elements. Therefore, although no direct current flows through the coil pattern CP, an LC circuit is formed by the parasitic capacitance generated between adjacent conductor patterns, and resonance occurs in a predetermined frequency band. By setting the predetermined frequency band in which this resonance occurs to match the frequency band of short-range wireless communication (for example, the 13.56 MHz band), the antenna module 1 can perform short-range wireless communication.

[0018] The first coil section 100 has sections 101 and 102 extending in the X direction, which is the short side direction, and sections 103 and 104 extending in the Y direction, which is the long side direction. The sections 101 to 104 constituting the first coil section 100 all overlap with the magnetic body 20 without overlapping with the through hole 21. In the example shown in FIG. 3, the first coil section 100 has approximately 3 turns.

[0019] The first coil section 100 is a conductor pattern that circulates so as to have a rectangular shape corresponding to the outer shape of the IC card 2 in a plan view seen from the Z direction. However, the first coil section 100 does not necessarily have to be a precise rectangular shape, and it may be approximately rectangular. For example, as shown in FIG. 3, the first coil section 100 may have a shape in which four corners (corner portions) are curved. In this case, the short side of the first coil section 100 may be a straight section extending in the X direction, and the long side of the first coil section 100 may be a straight section extending in the Y direction.

[0020] The second coil section 200 has a first extending section 210 extending along the first coil section 100, and a second extending section 220 that protrudes from the first extending section 210 toward the through hole 21 of the magnetic body 20 in a plan view seen from the Z direction and overlaps with the through hole 21 in a plan view. Here, the pattern width of the second extending section 220 is narrower than the pattern width of the first extending section 210, and the conductor pattern turns more densely. Thereby, while reducing the resistance value of the first extending section 210, it is possible to sufficiently secure the number of wirings of the second extending section 220 that turns within a narrow region. In the example shown in FIG. 3, the second coil section 200 has approximately 7 turns.

[0021] The first extending section 210 of the second coil section 200 has sections 211 to 214 that go around along sections 101 to 104 of the first coil section 100. All of the sections 211 to 214 that make up the first extending section 210 overlap with the magnetic body 20 without overlapping with the through hole 21. The through hole 21 is provided in the vicinity of the section 211, and the second coil section 200 transitions from the first extending section 210 to the second extending section 220 at a position that overlaps with the through hole 21 in the Y direction. The second extending section 220 of the second coil section 200 has first, second, and third sections 221 to 223 that extend along the second, third, and fourth sides L2 to L4 of the through hole 21, respectively. As a result, most of the first, second, and third sections 221 to 223 that make up the second extending section 220 do not overlap with the magnetic body 20. Here, the first and second sides L1, L2 of the through hole 21 extend in the X direction along the short sides of the first coil section 100 and are located on opposite sides of each other. The third and fourth sides L3, L4 of the through hole 21 extend in the Y direction along the long sides of the first coil section 100 and are located on opposite sides of each other. The first side L1 of the through hole 21 is located closer to the first coil section 100 than the second side L2 of the through hole 21 in the Y direction. Thus, since the second extending section 220 includes the first section 221 that extends in the X direction and the second and third sections 222, 223 that extend in the Y direction, although it does not completely go around at the portion overlapping with the through hole 21, it turns approximately 270°, so it functions as an antenna coil that electromagnetically couples with the IC module 50. Note that although most of the second and third sections 222, 223 overlap with the through hole 21, they do not overlap with the through hole 21 in the vicinity where they are connected to the first extending section 210.

[0022] Thus, when a current flows from the outer peripheral end to the inner peripheral end of the coil pattern CP, a current flows counterclockwise in the first extending section 210 of the second coil section 200, and a current flows clockwise in the second extending section 220 of the second coil section 200. That is, the turning direction of the first extending section 210 overlapping the magnetic body 20 and the turning direction of the second extending section 220 not overlapping the magnetic body 20 are opposite to each other. The second extending section 220 of the second coil section 200 does not have a section along the first side L1 of the through hole 21. For this reason, the second section 222 extending in the Y direction is directly connected to the section 211 extending in the X direction without passing through a section along the first side L1. Similarly, the third section 223 extending in the Y direction is directly connected to the section 211 extending in the X direction without passing through a section along the first side L1.

[0023] The third coil section 300 has sections 301 and 302 extending in the X direction which is the short side direction, and sections 303 and 304 extending in the Y direction which is the long side direction. All of the sections 301 to 304 constituting the third coil section 300 overlap the magnetic body 20 without overlapping the through hole 21. In the example shown in FIG. 3, the third coil section 300 has about 9 turns, which is more than the number of turns of the first coil section 100.

[0024] With such a configuration, the first coil section 100 overlapping the magnetic body 20, the first extending section 210 of the second coil section 200, and the third coil section 300 function as an antenna coil, and communication can be performed from the other surface 2b side of the IC card 2. On the other hand, the second extending section 220 of the second coil section 200 does not overlap the magnetic body 20 and faces the IC module 50 through the through hole 21 provided in the magnetic body 20, so it electromagnetically couples with the IC module 50. As a result, the first coil section 100 functioning as an antenna coil, the first extending section 210 of the second coil section 200, and the third coil section 300 are connected to the IC module 50 via the second extending section 220 functioning as a coupling coil.

[0025] And, in the antenna module 1 according to the present embodiment, since the coil pattern CP is provided only on one surface 31 of the base material 30 and no conductor pattern is provided on the other surface 32 of the base material 30, it can be manufactured by a very simple process. Moreover, in the present embodiment, the number of turns of the third coil section 300 located on the inner peripheral side and having a shorter line length per turn is larger than the number of turns of the first coil section 100 located on the outer peripheral side and having a longer line length per turn. Therefore, the second extending section 220 of the second coil section 200 that functions as a coupling coil is located closer to the center of the line length, and it becomes possible to enhance the output of electromagnetic field coupling through the second extending section 220.

[0026] FIG. 4 is a schematic perspective view of the IC module 50 seen from the back side.

[0027] As shown in FIG. 4, the IC module 50 includes a module substrate 51 and an IC chip 52 mounted or incorporated therein, and a coupling coil CC is formed on the back side of the module substrate 51. On the front side of the module substrate 51, the terminal electrode E shown in FIG. 1 is provided. When the coupling coil CC is superposed on the second extending section 220 of the second coil section 200 of the coil pattern CP provided on the base material 30, electromagnetic field coupling occurs. Thereby, the first coil section 100, the first extending section 210 of the second coil section 200, and the third coil section 300 of the coil pattern CP that function as antenna coils can be connected to the IC module 50 through the coupling coil CC without directly connecting them to the IC module 50 using a terminal electrode or the like.

[0028] FIG. 5 is a schematic plan view showing the pattern shape of the coil pattern CP according to the first modification.

[0029] The coil pattern CP according to the first modification example shown in FIG. 5 is different from the coil pattern CP shown in FIG. 3 in that the third coil section 300 circulates along the first and second extending sections 210 and 220 of the second coil section 200. Since the other basic configurations are the same as those of the coil pattern CP shown in FIG. 3, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0030] In the coil pattern CP according to the first modification example, the third coil section 300 includes sections 301 to 305, sections 301 to 304 circulate along sections 211 to 214 of the first extending section 210, and section 305 circulates along the second extending section 220. Therefore, when a current flows from the outer peripheral end to the inner peripheral end of the coil pattern CP, a current flows counterclockwise (anticlockwise) in sections 301 to 304 of the third coil section 300, and a current flows clockwise in section 305 of the third coil section 300. In this way, by circulating the third coil section 300 along the first and second extending sections 210 and 220 of the second coil section 200, the parasitic capacitance increases, so that the self-resonant frequency can be reduced.

[0031] FIG. 6 is a schematic plan view showing the pattern shape of the coil pattern CP according to the second modification example.

[0032] The coil pattern CP according to the second modification example shown in FIG. 6 is different from the coil pattern CP shown in FIG. 3 in that the second extending section 220 of the second coil section 200 further has a fourth section 224 extending along the first side L1 of the through hole 21. Since the other basic configurations are the same as those of the coil pattern CP shown in FIG. 3, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0033] In the coil pattern CP according to the second modification example, the amount of circulation of the second extending section 220 in the portion overlapping the through hole 21 increases. As exemplified by the second modification example, the second and third sections 222 and 223 extending in the Y direction may be connected to the section 211 extending in the X direction via the fourth section 224 along the first side L1.

[0034] As described above, the preferred embodiments of the present disclosure have been explained. 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.

[0035] For example, in the above embodiment, the coil pattern CP is composed of the first coil section 100, the second coil section 200, and the third coil section 300, but the third coil section 300 may be omitted. Further, the second extending section 220 included in the second coil section 200 is not limited to one location, and when there are a plurality of IC modules 50, a plurality of second extending sections 220 overlapping with the plurality of IC modules 50 via the through holes 21 may be provided.

[0036] The technology according to the present disclosure includes the following configuration examples, but is not limited thereto.

[0037] The antenna module according to the present disclosure includes a base material, a coil pattern provided on one surface of the base material, and a magnetic body covering the other surface of the base material and having a through hole. The coil pattern has first and second coil sections. The second coil section is disposed within the opening of the first coil section. The inner peripheral end of the first coil section is connected to the outer peripheral end of the second coil section. The second coil section has a first extending section extending along the first coil section, and a second extending section that protrudes from the first extending section toward the through hole in a plan view and turns in a direction opposite to the first extending section in a state of overlapping the through hole. According to this, since it is not necessary to form a conductor pattern on the other surface of the base material, the manufacturing process can be simplified.

[0038] Both ends of the coil pattern may be open. According to this, since it is not necessary to connect the coil pattern to other circuit elements or the like, the manufacturing process can be further simplified.

[0039] The through-hole has a first and a second side that extend along the short side of the first coil section and are located on opposite sides of each other, and a third and a fourth side that extend along the long side of the first coil section and are located on opposite sides of each other. The second extending section may have a first, a second, and a third section that extend along the second, the third, and the fourth side respectively. According to this, it becomes possible to sufficiently ensure electromagnetic field coupling with the IC module. In this case, the second and the third section may be connected to the first extending section without passing through the section along the first side. According to this, since the magnetic fields generated by the folding of the conductor pattern do not cancel each other out, it becomes possible to improve the communication characteristics.

[0040] The pattern width of the second extending section may be narrower than the pattern width of the first extending section. According to this, while reducing the resistance value of the first extending section, it becomes possible to sufficiently ensure the number of wirings of the second extending section that turns within a narrow area.

[0041] The coil pattern further has a third coil section that is disposed within the opening of the second coil section and does not overlap with the through-hole, and the inner peripheral end of the second coil section may be connected to the outer peripheral end of the third coil section. According to this, higher communication characteristics can be obtained and it becomes possible to reduce the self-resonant frequency. In this case, the third coil section may turn along the first and the second extending sections of the second coil section. According to this, it becomes possible to further reduce the self-resonant frequency. Also, the number of turns of the third coil section may be more than the number of turns of the first coil section. According to this, it becomes possible to dispose the second coil section at a portion closer to the center of the line length.

Explanation of Signs

[0042] 1 Antenna module 2 IC card 2a One surface of the IC card 2b The other surface of the IC card 4 Card reader 10 Metal plate 11 Opening 20 Magnetic body 21 Through-hole 30 Substrate 31 One surface of the substrate 32 The other surface of the substrate 40 Cover layer 50 IC module 51 Module substrate 52 IC chip 100 First coil section 101 - 104 Sections 200 Second coil section 210 First extending section 211 - 214 Sections 220 Second extending section 221 First section 222 Second section 223 Third section 224 Fourth section 300 Third coil section 301 - 305 Sections CC Coupling coil CP Coil pattern E Terminal electrode L1 First side L2 Second side L3 Third side L4 Fourth side

Claims

1. a base material; a coil pattern provided on one surface of the base material; a magnetic body covering the other surface of the base material and having a through hole, and comprising: the coil pattern has first and second coil sections; the second coil section is disposed within the opening of the first coil section; the inner peripheral end of the first coil section is connected to the outer peripheral end of the second coil section; the second coil section has a first extending section extending along the first coil section, and a second extending section protruding from the first extending section toward the through hole in plan view and turning in a direction opposite to that of the first extending section while overlapping the through hole; an antenna module in which both ends of the coil pattern are open.

2. the through hole extends in a direction along the short side of the first coil section and has first and second sides located on opposite sides of each other, and third and fourth sides extending in a direction along the long side of the first coil section and located on opposite sides of each other; the antenna module according to claim 1, wherein the second extending section has first, second, and third sections extending along the second, third, and fourth sides, respectively.

3. a base material; a coil pattern provided on one surface of the base material; a magnetic body covering the other surface of the base material and having a through hole, and comprising: the coil pattern has first and second coil sections; the second coil section is disposed within the opening of the first coil section; the inner peripheral end of the first coil section is connected to the outer peripheral end of the second coil section; the second coil section has a first extending section extending along the first coil section, and a second extending section protruding from the first extending section toward the through hole in plan view and turning in a direction opposite to that of the first extending section while overlapping the through hole; the through hole extends in a direction along the short side of the first coil section and has first and second sides located on opposite sides of each other, and third and fourth sides extending in a direction along the long side of the first coil section and located on opposite sides of each other; the second extending section has first, second, and third sections extending along the second, third, and fourth sides, respectively; the antenna module, wherein the second and third sections are connected to the first extending section without passing through a section along the first side.

4. a base material; a coil pattern provided on one surface of the base material; a magnetic body covering the other surface of the base material and having a through hole, and comprising: The coil pattern has first and second coil sections, wherein the second coil section is disposed within the opening of the first coil section, the inner peripheral end of the first coil section is connected to the outer peripheral end of the second coil section, the second coil section has a first extending section extending along the first coil section, and a second extending section protruding from the first extending section toward the through hole in plan view and turning in a direction opposite to that of the first extending section while overlapping the through hole, the antenna module in which the pattern width of the second extending section is narrower than the pattern width of the first extending section. **Claim 5** A base material, a coil pattern provided on one surface of the base material, and a magnetic body covering the other surface of the base material and having a through hole. The coil pattern has first and second coil sections, wherein the second coil section is disposed within the opening of the first coil section, the inner peripheral end of the first coil section is connected to the outer peripheral end of the second coil section, the second coil section has a first extending section extending along the first coil section, and a second extending section protruding from the first extending section toward the through hole in plan view and turning in a direction opposite to that of the first extending section while overlapping the through hole, the coil pattern further has a third coil section disposed within the opening of the second coil section and not overlapping the through hole, the antenna module in which the inner peripheral end of the second coil section is connected to the outer peripheral end of the third coil section. **Claim 6** The antenna module according to claim 5, wherein the third coil section circulates along the first and second extending sections of the second coil section. **Claim 7** The antenna module according to claim 5 or 6, wherein the number of turns of the third coil section is larger than the number of turns of the first coil section.

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