Antenna module

Abstract

To provide an antenna module capable of ensuring flatness.SOLUTION: An antenna module 1 includes: a coil pattern C planarly wound in a plurality of turns; a first adhesive layer 10 attached to one surface of the coil pattern C in an axial direction; a second adhesive layer 20 attached to the other surface of the coil pattern C in the axial direction; and a magnetic member 30 attached to the first adhesive layer 10 and disposed on a side opposite to the coil pattern C as viewed from the first adhesive layer 10. The first and second adhesive layers 10, 20 bulge to a gap between the patterns of the coil pattern C. This makes it possible to ensure flatness.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a method of manufacturing an antenna module by attaching an adhesive layer to a coil pattern formed on the surface of a base material, then peeling off the base material, and attaching a magnetic body instead of the base material. As a result, since the base material is not included in the final product, the antenna module can be thinned.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the antenna module described in Patent Document 1 has a problem that when the antenna module is attached to an object, flatness is lost because large irregularities occur in the adhesive layer.

[0005] Therefore, an object of the present disclosure is to provide an antenna module capable of ensuring flatness.

Means for Solving the Problems

[0006] An antenna module according to an embodiment of the present disclosure includes a coil pattern that turns in a plurality of turns in a planar shape, a first adhesive layer adhered to one surface in the coil axis direction of the coil pattern, a second adhesive layer adhered to the other surface in the coil axis direction of the coil pattern, and a magnetic body adhered to the first adhesive layer and disposed on the opposite side of the coil pattern when viewed from the first adhesive layer. The first and second adhesive layers bulge into the gaps between the patterns of the coil pattern.

Effect of the Invention

[0007] According to the present disclosure, it is possible to provide an antenna module capable of ensuring flatness.

Brief Description of the Drawings

[0008]

Figure 1

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Figure 9

Best Mode 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 cross-sectional view for explaining the structure of the antenna module 1 according to the first embodiment of the present disclosure.

[0011] As shown in FIG. 1, the antenna module 1 according to the first embodiment includes a coil pattern C that turns in a plurality of turns in a planar shape, a first adhesive layer 10 adhered to one surface of the coil pattern C in the coil axis direction, a second adhesive layer 20 adhered to the other surface of the coil pattern C in the coil axis direction, a magnetic body 30 adhered to the first adhesive layer 10 and disposed on the opposite side of the coil pattern C as viewed from the first adhesive layer 10, a metal member 40 disposed on the opposite side of the first adhesive layer 10 as viewed from the magnetic body 30, and a liner layer 50 adhered to the second adhesive layer 20 and disposed on the opposite side of the coil pattern C as viewed from the second adhesive layer 20.

[0012] The antenna module 1 can be connected to, for example, a near-field communication (NFC) circuit (not shown) and function as an NFC antenna coil that performs near-field wireless communication with a communication target device. Further, the antenna module 1 can also function as a wireless power transmission coil that performs wireless power supply using a frequency band of near-field wireless communication (for example, 13.56 MHz band), and may function as a coil that performs both near-field wireless communication and wireless power supply.

[0013] As shown in FIG. 2 which is a plan view, the coil pattern C is a planar spiral conductor pattern that circulates over a plurality of turns and is made of a good conductor such as Cu. The coil pattern C circulates while providing a gap between adjacent turns. In the example shown in FIGS. 1 and 2, the number of turns of the coil pattern C is 4 turns, but the number of turns of the coil pattern C is not particularly limited. Also, the planar shape of the coil pattern C is not limited to a rectangular shape and may be circular or elliptical.

[0014] FIG. 3 is a schematic cross-sectional view of the region A shown in FIG. 1 enlarged.

[0015] As shown in FIG. 3, the first adhesive layer 10 has an adhesive surface 11 adhered to the coil pattern C and an adhesive surface 12 adhered to the magnetic body 30. Thereby, the coil pattern C and the magnetic body 30 are fixed to each other by the first adhesive layer 10. As the first adhesive layer 10, a pressure-sensitive adhesive such as a heat-resistant acrylic adhesive, a silicone adhesive, a urethane adhesive, or a rubber-based adhesive can be used. The magnetic body 30 is a member that serves as a magnetic path for the magnetic field generated by the coil pattern C, and a material obtained by curing a paste-like member in which magnetic particles and resin are mixed may be used, or a sheet-like member may be used. In actual use, the antenna module 1 is arranged with respect to the communication target device so that the coil pattern C is located between the communication target device and the magnetic body 30. The metal member 40 mainly serves to reflect electromagnetic wave noise in the high-frequency region.

[0016] The second adhesive layer 20 has an adhesive surface 21 adhered to the coil pattern C and an adhesive surface 22 adhered to the liner layer 50. Thereby, the coil pattern C and the liner layer 50 are fixed to each other by the second adhesive layer 20. As the second adhesive layer 20, a pressure-sensitive adhesive such as an acrylic adhesive, a silicone adhesive, a urethane adhesive, or a rubber-based adhesive having heat resistance can be used. The liner layer 50 is peeled off when the antenna module 1 according to the present embodiment is mounted on a communication device. That is, the liner layer 50 serves to cover the adhesive surface 22 of the second adhesive layer 20 in a state before the antenna module 1 according to the present embodiment is mounted on a communication device. Then, when the antenna module 1 according to the present embodiment is mounted on a communication device, the liner layer 50 is peeled off, and the exposed adhesive surface 22 of the second adhesive layer 20 is attached to the communication device.

[0017] Thus, the antenna module 1 according to the present embodiment has a structure in which the coil pattern C is sandwiched between the first and second adhesive layers 10 and 20 from both sides in the coil axis direction. Further, as shown in FIG. 3, the first adhesive layer 10 has a bulging portion 13 that bulges into the gap between the patterns of the coil pattern C, and the second adhesive layer 20 has a bulging portion 23 that bulges into the gap between the patterns of the coil pattern C. The bulging portions 13 and 23 are portions generated by the deformation of the first and second adhesive layers 10 and 20, respectively, and the adhesion to the coil pattern C is enhanced by contacting a part of the side surface of the coil pattern C. Moreover, since the bulging portions 13 and 23 penetrate into the gap between the patterns of the coil pattern C from both sides in the coil axis direction, minute metal residues that may remain between the patterns depending on the manufacturing conditions do not move and are fixed by the bulging portions 13 and 23. Thereby, it becomes possible to prevent a progressive short-circuit defect caused by such metal residues. The bulging portions 13 and 23 may be in contact with each other between the patterns of the coil pattern C.

[0018] Here, the coil pattern C has a cross-sectional shape in which the pattern width becomes wider as it approaches the first adhesive layer 10. However, the coil pattern C does not necessarily have to change in pattern width across the entire cross-section, and a portion where the pattern width does not change may be included. This is due to the manufacturing process. That is, in manufacturing the antenna module 1 according to the present embodiment, first, as shown in FIG. 4, the coil pattern C is formed on the surface of an insulating base material 70 made of PET (polyethylene terephthalate) or the like. At this time, the pattern width of the coil pattern C becomes slightly narrower as it moves away from the base material 70. Next, as shown in FIG. 5, a laminate of the second adhesive layer 20 and the liner layer 50 is prepared, and the adhesive surface 21 of the second adhesive layer 20 is pressed against the coil pattern C to bond the two. At this time, the second adhesive layer 20 is deformed, and a bulging portion 23 is generated between the patterns of the coil pattern C. After that, after peeling off the base material 70, a laminate of the first adhesive layer 10, the magnetic body 30, and the metal member 40 is prepared, and the adhesive surface 11 of the first adhesive layer 10 is pressed against the coil pattern C to bond the two. At this time, the first adhesive layer 10 is deformed, and a bulging portion 13 is generated between the patterns of the coil pattern C.

[0019] In addition, when the first adhesive layer 10 is adhered to one surface of the coil pattern C, since the second adhesive layer 20 exists on the other surface of the coil pattern C, the deformation is dispersed between the deformation of the first adhesive layer 10 and the deformation of the second adhesive layer 20, and high flatness as the antenna module 1 can be ensured.

[0020] Here, since the pattern width of the coil pattern C becomes narrower as it approaches the second adhesive layer 20, even when the first adhesive layer 10 and the second adhesive layer are made of the same material, the bulging amount of the second adhesive layer 20 is larger. As a result, the flatness of the adhesive surface 22 of the second adhesive layer 20 deteriorates. In order to suppress this, it is preferable to make the thickness of the first adhesive layer 10 thinner than the thickness of the second adhesive layer 20. According to this, even when the bulging amount of the second adhesive layer 20 is large, it is possible to sufficiently ensure the flatness of the adhesive surface 22. On the other hand, since the bulging amount of the first adhesive layer 10 is small, even when its thickness is thinner than that of the second adhesive layer 20, the flatness of the adhesive surface 12 is ensured, and thereby it is possible to suppress the variation in the distance between the coil pattern C and the magnetic body 30. The bulging amount of the first adhesive layer 10 is the amount protruding toward the second adhesive layer 20 from the position of the interface between the adhesive surface 11 of the first adhesive layer 10 and the coil pattern C, and the bulging amount of the second adhesive layer 20 is the amount protruding toward the first adhesive layer 10 from the position of the portion closest to the liner layer 50 at the interface between the adhesive surface 21 of the second adhesive layer 20 and the coil pattern C.

[0021] As described above, since the antenna module 1 according to the present embodiment does not include a base material as an antenna module, it is possible to achieve thinning. Further, in the antenna module 1 according to the present embodiment, since the coil pattern C is sandwiched between the first and second adhesive layers 10 and 20 from both sides in the coil axis direction, it is possible to ensure high flatness and prevent progressive short-circuit failures caused by metal residues.

[0022] Here, in order to further enhance flatness, as shown in FIG. 1, a non-conductive member 60 may be disposed within the opening of the coil pattern C. The non-conductive member 60 is made of a resin material having heat resistance or the like, and is fixed within the opening of the coil pattern C by being adhered to at least one of the first and second adhesive layers 10 and 20. By adhering this non-conductive member 60 to both the first and second adhesive layers 10 and 20, the coil pattern C and the first and second adhesive layers 10 and 20 can be more firmly fixed. And if the thickness of the non-conductive member 60 is made substantially the same as the thickness of the coil pattern C, no recess will occur in the first and second adhesive layers 10 and 20 at the portion overlapping the opening of the coil pattern C, so that higher flatness can be obtained. Here, when it is necessary to give the antenna module 1 sufficient flexibility, it is preferable to use a material having a smaller Young's modulus than the metal material constituting the coil pattern C as the material of the non-conductive member 60. According to this, it is possible to suppress a decrease in flexibility due to the use of the non-conductive member 60.

[0023] Note that if the planar size of the non-conductive member 60 is made substantially the same as the size of the opening region of the coil pattern C, flatness can be further enhanced.

[0024] Alternatively, as in the antenna module 2 according to the second embodiment shown in FIG. 6, a depression 42 along the pattern shape of the coil pattern C may be provided on the inner surface 41 on the magnetic body 30 side of the metal member 40. According to this, as shown in FIG. 7 which is a schematic cross-sectional view with the region B shown in FIG. 6 enlarged, since the first adhesive layer 10 and the magnetic body 30 are deformed toward the metal member 40 side at the portion where the coil pattern C is provided, it is possible to absorb the unevenness due to the thickness of the coil pattern C by the depression 42.

[0025] Note that since the first adhesive layer 10 and the magnetic body 30 are deformed in a mountain shape toward the metal member 40 side, the depression 42 can absorb the entire deformed portion of the first adhesive layer 10 and the magnetic body 30 by making the depression wider than the winding width from the inner edge of the innermost turn to the outer edge of the outermost turn of the coil pattern C.

[0026] FIG. 8 is a schematic plan view for explaining the structure of the antenna module 3 according to the third embodiment of the present disclosure, showing a state as viewed from the side of the metal member 40.

[0027] The antenna module 3 according to the third embodiment shown in FIG. 8 is different from the antenna module 2 according to the second embodiment in that the metal member 40 is provided with a slit SL1. Since the other basic configurations are the same as those of the antenna module 2 according to the second embodiment, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted. The slit SL1 is provided so as to divide the metal member 40 into two. By providing such a slit SL1, eddy currents are interrupted at this portion. As a result, the counter magnetic field is suppressed, and thus deterioration of communication characteristics can be suppressed.

[0028] FIG. 9 is a schematic plan view for explaining the structure of the antenna module 4 according to the fourth embodiment of the present disclosure, showing a state as viewed from the side of the metal member 40.

[0029] The antenna module 4 according to the fourth embodiment shown in FIG. 9 is different from the antenna module 2 according to the second embodiment in that the metal member 40 is provided with a slit SL2. Since the other basic configurations are the same as those of the antenna module 2 according to the second embodiment, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted. The slit SL2 is provided so as to divide one side of the metal member 40 without completely dividing the metal member 40. By providing such a slit SL2, the direction of eddy currents is partially reversed. As a result, the counter magnetic field is suppressed, and thus deterioration of communication characteristics can be suppressed.

[0030] As described above, the preferred 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.

[0031] The technology according to the present disclosure includes, but is not limited to, the following configuration examples.

[0032] The antenna module according to the present disclosure includes a coil pattern that turns in a plurality of turns in a planar shape, a first adhesive layer adhered to one surface in the coil axis direction of the coil pattern, a second adhesive layer adhered to the other surface in the coil axis direction of the coil pattern, and a magnetic body adhered to the first adhesive layer and disposed on the opposite side of the coil pattern when viewed from the first adhesive layer. The first and second adhesive layers bulge into the gaps between the patterns of the coil pattern. According to this, high flatness can be ensured and progressive short circuit failures can be prevented.

[0033] The antenna module according to the present disclosure may further include a non-conductive member disposed in the opening of the coil pattern and adhered to at least one of the first and second adhesive layers. According to this, the recesses generated in the portion overlapping the opening of the coil pattern can be suppressed. Further, the non-conductive member may be adhered to both the first and second adhesive layers. According to this, the coil pattern and the first and second adhesive layers can be firmly fixed. Also, the thickness of the non-conductive member may be the same as the thickness of the coil pattern. According to this, it is possible to obtain higher flatness. Also, the Young's modulus of the non-conductive member may be smaller than the Young's modulus of the member constituting the coil pattern. According to this, it is possible to ensure the flexibility of the entire antenna module.

[0034] The coil pattern has a cross-sectional shape in which the pattern width becomes wider as it approaches the first adhesive layer, and the thickness of the first adhesive layer may be thinner than the thickness of the second adhesive layer. According to this, it is possible to suppress a decrease in flatness due to the bulging portion. In this case, the amount of bulging of the second adhesive layer into the gaps between the patterns may be larger than the amount of bulging of the first adhesive layer into the gaps between the patterns. According to this, it is possible to suppress variations in the distance between the coil pattern and the magnetic body.

[0035] The antenna module according to the present disclosure may further include a metal member disposed on the side opposite to the first adhesive layer when viewed from the magnetic body. According to this, it becomes possible to mainly reflect electromagnetic wave noise in the high-frequency region. In this case, the inner surface on the magnetic body side of the metal member may have a depression along the pattern shape of the coil pattern. According to this, it becomes possible to suppress the depression generated in the portion overlapping the opening of the coil pattern. Further, the metal member may be provided with a slit. According to this, since the demagnetizing field is suppressed, it becomes possible to suppress the deterioration of the communication characteristics.

Description of reference numerals

[0036] 1 to 4 Antenna module 10 First adhesive layer 11, 12 Adhesive surfaces of the first adhesive layer 13 Bulge of the first adhesive layer 20 Second adhesive layer 21, 22 Adhesive surfaces of the second adhesive layer 23 Bulge of the second adhesive layer 30 Magnetic body 40 Metal member 41 Inner surface of the metal member 42 Depression 50 Liner layer 60 Non-conductive member 70 Base material C Coil pattern SL1, SL2 Slit

Claims

1. A coil pattern that turns in a plurality of turns in a planar shape, A first adhesive layer adhered to one surface in the coil axis direction of the coil pattern, A second adhesive layer adhered to the other surface in the coil axis direction of the coil pattern, A magnetic body that is adhered to the first adhesive layer and is disposed on the opposite side of the coil pattern when viewed from the first adhesive layer, and The first and second adhesive layers bulge into the gaps between the patterns of the coil pattern, The coil pattern has a cross-sectional shape in which the pattern width becomes wider in a direction perpendicular to the thickness direction as it approaches the first adhesive layer in the thickness direction of the first adhesive layer, An antenna module in which the thickness of the first adhesive layer is thinner than the thickness of the second adhesive layer.

2. The antenna module according to claim 1, further comprising a non-conductive member disposed in the opening of the coil pattern and adhered to at least one of the first and second adhesive layers.

3. The antenna module according to claim 2, wherein the non-conductive member is adhered to both the first and second adhesive layers.

4. The antenna module according to claim 2 or 3, wherein the thickness of the non-conductive member is the same as the thickness of the coil pattern.

5. The antenna module according to any one of claims 2 to 4, wherein the Young's modulus of the non-conductive member is smaller than the Young's modulus of the member constituting the coil pattern.

6. The antenna module according to any one of claims 1 to 5, wherein the amount of bulging of the second adhesive layer into the gaps between the patterns is larger than the amount of bulging of the first adhesive layer into the gaps between the patterns.

7. The antenna module according to any one of claims 1 to 6, further comprising a metal member disposed on the side opposite to the first adhesive layer when viewed from the magnetic body.

8. The antenna module according to claim 7, wherein the inner surface of the metal member on the magnetic body side has a depression along the pattern shape of the coil pattern.

9. The antenna module according to claim 7 or 8, wherein a slit is provided in the metal member.

10. A coil pattern that winds around a plurality of turns in a planar shape, A first adhesive layer adhered to one surface in the coil axis direction of the coil pattern, A second adhesive layer adhered to the other surface in the coil axis direction of the coil pattern, A magnetic body adhered to the first adhesive layer and disposed on the side opposite to the coil pattern when viewed from the first adhesive layer, And a metal member disposed on the side opposite to the first adhesive layer when viewed from the magnetic body, The first and second adhesive layers bulge into the gaps between the patterns of the coil pattern, An antenna module, wherein the inner surface of the metal member on the magnetic body side has a depression along the pattern shape of the coil pattern.

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