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 technology]

[0002] Patent Document 1 discloses an IC card with a wireless communication function. The IC card described in Patent Document 1 incorporates an antenna module including a magnetic body, an antenna coil overlapping the magnetic body, and a coupling coil overlapping a through-hole in the magnetic body, and an IC module that is electromagnetically coupled to the coupling coil. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-195050 Summary of the Invention [Problem to be solved by the invention]

[0004] In the antenna module described in Patent Document 1, an antenna coil is formed on one surface of a substrate, and a coupling coil is formed on the other surface of the substrate. This requires that conductor patterns be formed on both surfaces of the substrate, and that via conductors be provided to connect the conductor patterns formed on both surfaces of the substrate, leaving room for improvement in terms of the manufacturing process.

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

[0006] An antenna module according to one embodiment of the present disclosure comprises a substrate, a coil pattern provided on one surface of the substrate, and a magnetic body covering the other surface of the substrate and having a through hole, wherein the coil pattern has first and second coil sections, the second coil section being positioned within an opening of the first coil section, the inner peripheral end of the first coil section being connected to the outer peripheral end of the second coil section, and the second coil section having a first extension section extending along the first coil section and a second extension section that protrudes from the first extension section toward the through hole in a planar view and overlaps with the through hole while rotating in the opposite direction to the first extension section. [Effects of the Invention]

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

[0008] [Figure 1] FIG. 1 is a schematic perspective view showing the appearance of an IC card 2 equipped with an antenna module according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic exploded perspective view illustrating the structure of an IC card 2 including an antenna module 1 according to an embodiment of the present disclosure. [Figure 3] FIG. 3 is a schematic plan view showing the pattern shape of the coil pattern CP formed on one surface 31 of the substrate 30. As shown in FIG. [Figure 4] FIG. 4 is a schematic perspective view of the IC module 50 as seen from the rear side. [Figure 5] FIG. 5 is a schematic plan view showing the pattern shape of the coil pattern CP according to the first modified example. [Figure 6] FIG. 6 is a schematic plan view showing the pattern shape of the coil pattern CP according to the second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferred embodiments of the present disclosure will now 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 equipped with an antenna module according to an embodiment of the present disclosure.

[0011] 1, the IC card 2 according to this embodiment is a plate-like body with the Y direction as the longitudinal direction, the X direction as the lateral direction, and the Z direction as the thickness direction, and has a top surface 2a and a back surface 2b that form the XY plane. The IC card 2 has an IC module (described later) built in, and terminal electrodes E of the IC module are exposed on the top surface 2a of the IC card 2. The IC card 2 can communicate with a card reader 4 by facing the back surface 2b.

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

[0013] 2 has a structure in which a metal plate 10, a magnetic body 20, a substrate 30, and a cover layer 40 are laminated in this order from one surface 2a toward the other surface 2b. 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 substrate 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 substrate 30, and no via conductors penetrating the substrate 30 are provided. The other surface of the substrate 30 is covered with a magnetic body 20. The magnetic body 20 has through holes 21. The magnetic body 20 may be a material obtained by hardening a paste-like material in which magnetic particles and resin are mixed, or may be a sheet-like material. The antenna module 1 according to this embodiment is composed of the substrate 30, the conductor pattern formed on its surface, and the magnetic body 20.

[0015] 3 is a schematic plan view showing the pattern shape of the coil pattern CP formed on one surface 31 of the substrate 30. In FIG. 3, the through-holes 21 of the magnetic body 20 located on the other surface 32 side of the substrate 30 are indicated by dashed lines.

[0016] As shown in FIG. 3 , the coil pattern CP provided on one surface 31 of the substrate 30 includes a first coil section 100 and a third coil section 300 that function as antenna coils, 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 circumferential end toward the inner circumferential end of the coil pattern CP. That is, the inner circumferential end of the first coil section 100 is connected to the outer circumferential end of the second coil section 200, and the inner circumferential end of the second coil section 200 is connected to the outer circumferential 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, i.e., the outer peripheral end of the first coil section 100 and the inner peripheral end of the third coil section 300, are open. In other words, 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, no direct current flows through the coil pattern CP, but an LC circuit is formed by the parasitic capacitance generated between adjacent conductor patterns, causing resonance in a predetermined frequency band. Then, by matching the predetermined frequency band in which this resonance occurs to a frequency band for short-range wireless communication (e.g., the 13.56 MHz band), the antenna module 1 becomes capable of 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 that make up the first coil section 100 all overlap the magnetic body 20 without overlapping the through-hole 21. In the example shown in FIG. 3, the first coil section 100 has approximately three turns.

[0019] The first coil section 100 is a conductor pattern that winds around to form a rectangular shape that corresponds to the outline of the IC card 2 when viewed in a plan view from the Z direction. However, the first coil section 100 does not need to be a strict rectangular shape, as long as it is roughly rectangular. For example, as shown in FIG. 3, the first coil section 100 may have a shape with four curved corners. In this case, the short sides of the first coil section 100 may be straight sections that extend in the X direction, and the long sides of the first coil section 100 may be straight sections that extend in the Y direction.

[0020] The second coil section 200 has a first extension section 210 extending along the first coil section 100, and a second extension section 220 protruding from the first extension section 210 toward the through-hole 21 of the magnetic body 20 in a plan view seen from the Z direction and overlapping the through-hole 21 in a plan view. Here, the pattern width of the second extension section 220 is narrower than the pattern width of the first extension section 210, and the conductor pattern is wound more densely. This makes it possible to reduce the resistance value of the first extension section 210 while ensuring a sufficient number of wires in the second extension section 220 wound within a narrow area. In the example shown in FIG. 3, the second coil section 200 has approximately 7 turns.

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

[0022] As a result, when a current flows from the outer circumferential edge to the inner circumferential edge of the coil pattern CP, the current flows counterclockwise in the first extension section 210 of the second coil section 200 and clockwise in the second extension section 220 of the second coil section 200. In other words, the direction of rotation of the first extension section 210 overlapping the magnetic body 20 is opposite to the direction of rotation of the second extension section 220 not overlapping the magnetic body 20. The second extension section 220 of the second coil section 200 does not have a section along the first side L1 of the through hole 21. Therefore, the second section 222 extending in the Y direction is directly connected to the section 211 extending in the X direction without an intervening 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 an intervening 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 direction of the short side, and sections 303 and 304 extending in the Y direction, which is the direction of the long side. Sections 301 to 304 constituting the third coil section 300 all overlap with the magnetic body 20 without overlapping with the through-hole 21. In the example shown in FIG. 3, the third coil section 300 has approximately 9 turns, which is more than the number of turns of the first coil section 100.

[0024] With this configuration, the first coil section 100, the first extension section 210 of the second coil section 200, and the third coil section 300 that overlap the magnetic body 20 function as antenna coils, enabling communication from the other surface 2b side of the IC card 2. On the other hand, the second extension section 220 of the second coil section 200 does not overlap with the magnetic body 20 and faces the IC module 50 via the through hole 21 provided in the magnetic body 20, and is electromagnetically coupled to the IC module 50. As a result, the first coil section 100, the first extension section 210 of the second coil section 200, and the third coil section 300 that function as antenna coils are connected to the IC module 50 via the second extension section 220 that functions as a coupling coil.

[0025] The antenna module 1 according to this embodiment can be manufactured by a very simple process because the coil pattern CP is provided only on one surface 31 of the substrate 30, and no conductor pattern is provided on the other surface 32 of the substrate 30. Moreover, in this embodiment, the number of turns in the third coil section 300, which is located on the inner periphery and has a shorter line length per turn, is greater than the number of turns in the first coil section 100, which is located on the outer periphery and has a longer line length per turn. Therefore, the second extension section 220 of the second coil section 200, which functions as a coupling coil, is located closer to the center of the line length, and it is possible to increase the output of the electromagnetic field coupling via the second extension section 220.

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

[0027] As shown in FIG. 4, the IC module 50 includes a module substrate 51 and an IC chip 52 mounted on or built into the module substrate 51, and a coupling coil CC is formed on the back side of the module substrate 51. A terminal electrode E shown in FIG. 1 is provided on the front side of the module substrate 51. Electromagnetic field coupling occurs when the coupling coil CC overlaps the second extension section 220 of the second coil section 200 of the coil pattern CP provided on the base material 30. This allows the first coil section 100 of the coil pattern CP, the first extension section 210 of the second coil section 200, and the third coil section 300, which function as antenna coils, to be AC-connected to the IC module 50 via the coupling coil CC without directly connecting them using terminal electrodes or the like.

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

[0029] The coil pattern CP according to the first modified example shown in Fig. 5 differs from the coil pattern CP shown in Fig. 3 in that the third coil section 300 winds around along the first and second extension sections 210, 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 given the same reference numerals and redundant explanations will be omitted.

[0030] In the coil pattern CP according to the first modification, the third coil section 300 includes sections 301 to 305, with sections 301 to 304 winding around along sections 211 to 214 of the first extended section 210, and section 305 winding around along the second extended section 220. Therefore, when a current flows from the outer circumferential end to the inner circumferential end of the coil pattern CP, the current flows counterclockwise through sections 301 to 304 of the third coil section 300 and clockwise through section 305 of the third coil section 300. By winding the third coil section 300 around the first and second extended sections 210 and 220 of the second coil section 200 in this way, the parasitic capacitance increases, and therefore 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 modified example.

[0032] The coil pattern CP according to the second modified example shown in Fig. 6 differs from the coil pattern CP shown in Fig. 3 in that the second extension 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 configuration is the same as that of the coil pattern CP shown in Fig. 3, the same elements are given the same reference numerals and redundant explanations will be omitted.

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

[0034] The above describes preferred embodiments of the present disclosure, but the present disclosure is not limited to the above embodiments, and various modifications are possible within the scope of the present disclosure, and it goes without saying that these modifications are also included within the scope of the present disclosure.

[0035] For example, in the above embodiment, the coil pattern CP is configured by 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. Also, the second extension section 220 included in the second coil section 200 is not limited to one location, and if there are multiple IC modules 50, multiple second extension sections 220 may be provided that overlap with the multiple IC modules 50 via the through holes 21, respectively.

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

[0037] The antenna module according to the present disclosure includes a substrate, a coil pattern provided on one surface of the substrate, and a magnetic body covering the other surface of the substrate and having a through hole, the coil pattern having first and second coil sections, the second coil section being disposed within the opening of the first coil section, the inner peripheral end of the first coil section being connected to the outer peripheral end of the second coil section, the second coil section having a first extension section extending along the first coil section and a second extension section protruding from the first extension section toward the through hole in a plan view and overlapping with the through hole and turning in the opposite direction to the first extension section. This eliminates the need to form a conductor pattern on the other surface of the substrate, thereby simplifying the manufacturing process.

[0038] Both ends of the coil pattern may be open, which eliminates the need to connect the coil pattern to other circuit elements, thereby further simplifying the manufacturing process.

[0039] The through hole may have first and second sides extending along the short sides of the first coil section and positioned opposite each other, and third and fourth sides extending along the long sides of the first coil section and positioned opposite each other, and the second extension section may have first, second, and third sections extending along the second, third, and fourth sides, respectively. This allows for sufficient electromagnetic field coupling with the IC module. In this case, the second and third sections may be connected to the first extension section without an intervening section along the first side. This prevents magnetic fields from canceling out due to folding back the conductor pattern, thereby improving communication characteristics.

[0040] The pattern width of the second extension section may be narrower than the pattern width of the first extension section, which makes it possible to reduce the resistance value of the first extension section while ensuring a sufficient number of wirings in the second extension section that wind around within a narrow area.

[0041] The coil pattern may further include a third coil section disposed within the opening of the second coil section and not overlapping 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. This may provide higher communication characteristics and reduce the self-resonant frequency. In this case, the third coil section may be wound around the first and second extension sections of the second coil section. This may further reduce the self-resonant frequency. The number of turns in the third coil section may be greater than the number of turns in the first coil section. This may allow the second coil section to be disposed closer to the center of the line length. [Explanation of symbols]

[0042] 1 Antenna Module 2. IC card 2a One side of the IC card 2b The other side of the IC card 4. Card Reader 10 Metal Plate 11 Opening 20 Magnetic material 21 Through hole 30 Base material 31 One surface of the substrate 32 Other surface of the substrate 40 Cover Layer 50 IC modules 51 Module Board 52 IC chip 100 First coil section Section 101~104 200 Second coil section 210 1st extension section Section 211~214 220 Second extension section 221 Section 1 222 Section 2 223 Section 3 224 Section 4 300 Third coil section Section 301~305 CC coupling coil CP coil pattern E terminal electrode L1 First edge L2 Second edge L3 Third edge L4 Fourth edge

Claims

1. The coil pattern, a magnetic body having a through hole, the coil pattern has a first extension section extending along a periphery of the magnetic body, and a second extension section protruding from the first extension section toward the through hole in a plan view and winding in a direction opposite to that of the first extension section, the second extension section includes a plurality of first sections, a plurality of second sections extending from one end of each turn of the first extension section toward a corresponding one end of each of the plurality of first sections, and a plurality of third sections extending from the other end of each turn of the first sections toward a corresponding other end of each of the plurality of first extension sections, The pattern width of the second extension section is narrower than the pattern width of the first extension section. Antenna module.

2. The antenna module according to claim 1 , wherein both ends of the coil pattern are open.

3. The through hole has first and second sides that extend in a direction along the short side of the first extension section and are located opposite to each other, and third and fourth sides that extend in a direction along the long side of the first extension section and are located opposite to each other, The antenna module according to claim 1 , wherein the first, second, and third sections of the second extension section extend along the second, third, and fourth sides, respectively.

4. The antenna module according to claim 3 , wherein the second and third sections are connected to the first extending section without an intervening section along the first side.

5. the coil pattern further includes a third coil section that is disposed within an opening surrounded by the first and second extension sections and does not overlap with the through hole; The antenna module according to claim 1 , wherein an inner peripheral end of a second coil section including the first and second extension sections is connected to an outer peripheral end of the third coil section.

6. The antenna module according to claim 5 , wherein the third coil section is wound around the first and second extension sections of the second coil section.

7. A coil pattern; a magnetic body having a through hole, the coil pattern has a first extension section extending along a periphery of the magnetic body, and a second extension section protruding from the first extension section toward the through hole in a plan view and winding in a direction opposite to that of the first extension section, the second extension section includes a plurality of first sections, a plurality of second sections extending from one end of each turn of the first extension section toward a corresponding one end of each of the plurality of first sections, and a plurality of third sections extending from the other end of each turn of the first sections toward a corresponding other end of each of the plurality of first extension sections, the coil pattern further includes a third coil section that is disposed within an opening surrounded by the first and second extension sections and does not overlap with the through hole; an inner peripheral end of the second coil section including the first and second extension sections is connected to an outer peripheral end of the third coil section; The antenna module, wherein the coil pattern further includes a first coil section located between the first extension section and a periphery of the magnetic body.

8. The antenna module according to claim 7 , wherein the number of turns in the third coil section is greater than the number of turns in the first coil section.

Images