JP2015204554A - antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna device capable of further spreading directivity.SOLUTION: An antenna device 1 includes: a support body 10 having a curved surface; an extensible sheet 11 provided along a curved surface of the support body 10; and an antenna coil 12 provided on a surface of the extensible sheet 11. The antenna coil 12 is formed on a main surface of the extensible sheet 11 as a plane pattern. Then, the extensible sheet 11 is applied to the support body 10 thereby making the antenna coil 12 into a three-dimensional pattern along the curved surface of the support body 10.

Description

  The present invention relates to an antenna device, and more particularly to an antenna device suitable for NFC (Near Field Communication). The present invention also relates to a portable electronic device in which such an antenna device is mounted.

  In recent years, RFID (Radio Frequency Identification) systems are mounted on portable electronic devices such as smartphones, and NFC antennas are mounted as communication means therefor. In order for the NFC antenna to perform reliable communication with the counterpart device, wider directivity is required. For example, in Patent Document 1, the flexible substrate on which the antenna coil is formed is bent in one direction so that the antenna coil A method of giving wide directivity has been proposed.

Japanese Patent No. 5375899

  However, the conventional antenna described above does not have a sufficient spread of directivity, and further improvements are required.

  Accordingly, an object of the present invention is to provide an antenna device capable of further expanding directivity.

  In order to solve the above problems, an antenna device according to the present invention includes a support having a curved surface, an elastic sheet provided along the curved surface of the support, and an antenna provided on the surface of the sheet to be inserted. And a coil.

  According to the present invention, the directivity can be further expanded as compared with the conventional antenna device, and communication with the reader / writer can be performed reliably.

  In the present invention, the curved surface is preferably a dome shape or a chamfered corner shape. According to this configuration, the stretchable sheet can be easily bent, and thereby the directivity of the antenna coil can be expanded.

  In this invention, it is preferable that the said support body is a housing | casing of a portable electronic device, and the said curved surface is an inner surface of the corner part of the said housing | casing. The support may be a battery pack of a portable electronic device, and the curved surface may be a surface of a corner portion of the battery pack. In either case, the antenna coil can have a three-dimensional shape, and the directivity of the antenna can be expanded.

  ADVANTAGE OF THE INVENTION According to this invention, the antenna apparatus which can further expand directivity can be provided.

FIG. 1 is a schematic perspective view showing the structure of an antenna device according to a preferred embodiment of the present invention. 2 is a schematic exploded perspective view of the antenna device shown in FIG. FIG. 3 is a schematic diagram for explaining an example of the manufacturing method of the antenna device 1. FIG. 4 is a diagram for explaining the structure of the antenna device according to the second embodiment of the present invention. FIG. 5 is a diagram for explaining the structure of an antenna device according to the third embodiment of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic perspective view showing the structure of an antenna device according to a preferred embodiment of the present invention. FIG. 2 is a schematic exploded perspective view of the antenna device shown in FIG.

  As shown in FIGS. 1 and 2, the antenna device 1 includes a support 10 having a curved surface, a stretchable sheet 11 provided along the curved surface 10 a of the support 10, and a surface of the stretchable sheet 11. The antenna coil 12 is provided.

  The support 10 is provided to curve the stretchable sheet 11. The support 10 is preferably an insulator, but may be a conductor such as metal. The support 10 is curved in a plurality of directions and constitutes a three-dimensional curved surface. More specifically, it may be a dome shape curved with a constant curvature over the entire circumference, or a chamfered corner shape described later.

  The stretchable sheet 11 provides a ground for the antenna coil 12. Since the stretchable sheet 11 has stretchability, it can be deformed into a shape along the curved surface of the support 10. Although not particularly limited, examples of the elastic sheet 11 include silicone rubber and polyurethane. The stretchable sheet 11 does not necessarily need to be in close contact with the support 10 and may partially float from the support 10.

  As shown in FIG. 2, the antenna coil 12 is a coil conductor pattern having a planar spiral shape when the stretchable sheet 11 is flat, and is formed on one main surface of the stretchable sheet 11. The spiral shape of the antenna coil 12 is not particularly limited, and may be a circular spiral, a rectangular spiral, or a triangular spiral. The hollow area inside the spiral loop is preferably as large as possible so that the magnetic flux can easily pass through.

  The coil conductor pattern constituting the antenna coil 12 may be formed on both surfaces of the stretchable sheet. Therefore, for example, most of the coil conductor pattern may be formed on one main surface of the stretchable sheet 11 and the remaining portion may be formed on the other main surface of the stretchable sheet 11. Alternatively, most of the coil conductor pattern may be formed on the other main surface of the stretchable sheet 11 and the remaining portion may be formed on one main surface of the stretchable sheet. Further, the entire coil conductor pattern may be formed on the other main surface of the stretchable sheet 11.

  The antenna coil 12 is formed as a planar pattern on the main surface of the stretchable sheet 11, but the antenna coil 12 is also three-dimensional along the curved surface of the support 10 by pasting the stretchable sheet 11 to the support 10. It becomes a pattern. Since the direction of the magnetic flux φ penetrating the central portion of the antenna coil 12 is a normal direction perpendicular to the curved surface formed by the antenna coil 12, the direction of the magnetic flux φ can be widened. Therefore, the directivity of the antenna coil 12 can be expanded.

  FIG. 3 is a schematic diagram for explaining an example of the manufacturing method of the antenna device 1.

  In manufacturing the antenna device 1, first, the stretchable sheet 11 is prepared (FIG. 3A), and a resin pattern 13 including a catalyst is formed on the top surface of the stretchable sheet 11 (FIG. 3B). The planar shape of the resin pattern 13 is the same as the spiral pattern of the antenna coil 12. For example, an epoxy resin can be used as the resin. The catalyst is used for promoting the formation of a Cu film, which will be described later. For example, palladium can be used. The resin pattern 13 can be formed by screen-printing a resin paste mixed with a catalyst and then thermosetting.

  Next, a Cu film 15 is formed on the upper surface of the resin pattern 13 containing the catalyst by electroless plating (FIG. 3C), and further the Cu film 15 is grown by electrolytic plating (FIG. 3D). A Ni or Au plating film may be further formed on the Cu film.

  Next, a cover layer 16 (resist layer) that covers the entire surface of the stretchable sheet 11 on which the Cu film 15 is formed is formed (FIG. 3E). Thus, the structure of the antenna device 1 according to the present embodiment is completed. Further, by deforming this structure along the curved surface 10a of the support 10, the antenna device 1 according to the present embodiment shown in FIG. 1 is completed.

  As described above, the antenna device 1 according to the present embodiment has the antenna coil 12 formed in a three-dimensional manner along the curved surface, so that the radiation direction of magnetic flux can be widened and the antenna device has a wide directivity. Can be provided.

  FIG. 4 is a diagram for explaining the structure of the antenna device according to the second embodiment of the present invention, in which (a) is a schematic perspective view showing a state of being attached to a support, and (b). FIG. 3 is a schematic cross-sectional view of the antenna device of FIG.

  As shown in FIG. 4, the antenna device 2 is characterized in that the casing 20 of a portable electronic device such as a smartphone serves as a support for the stretchable sheet 11, and the stretchable sheet 11 is attached to the curved surface of the casing 20. It is in the point which is comprised. Other configurations are the same as those of the antenna device 1 according to the first embodiment.

As shown in FIG. 4A, the curved surface of the housing 20 is a surface of a corner portion that is chamfered in a round shape by intersecting three surfaces that are orthogonal to each other. Since the corner portion has the XY plane S _XY , the YZ plane S _YZ, and the ZX plane S _ZX , the stretchable sheet 11 also has these three surfaces. FIG. 4B shows a state in which the flat stretchable sheet 11 is attached along the inner surface of the corner portion of the housing 20.

  The stretchable sheet 11 provided along the corner portion of the housing 20 has a curved surface that curves in a plurality of directions, and the antenna coil 12 also has a three-dimensional pattern along the curved surface. As in the first embodiment, the direction of the magnetic flux φ penetrating the central portion of the antenna coil 12 is a normal direction perpendicular to the curved surface formed by the antenna coil 12, and therefore the direction of the magnetic flux φ should be widened. Can do. Therefore, the directivity of the antenna coil 12 can be expanded.

  Thus, in this embodiment, since the housing | casing 20 of the portable electronic device in which an antenna is integrated is utilized as a support body, the directivity of an antenna can be expanded without preparing a dedicated support body.

  FIG. 5 is a diagram for explaining the structure of an antenna device according to a third embodiment of the present invention, wherein (a) is a schematic perspective view showing a state of being attached to a support, and (b). FIG. 3 is a schematic cross-sectional view of the antenna device of FIG.

  As shown in FIG. 5, the antenna device 3 is characterized in that a battery pack 21 built in a portable electronic device such as a smartphone serves as a support for the stretchable sheet 11, and the stretchable sheet 11 is formed on the curved surface of the battery pack 21. It is in the point where it is pasted and constituted. When the surface of the battery pack 21 is a metal, it is preferable that a magnetic material is provided between the battery pack 21 and the stretchable sheet 11. Other configurations are the same as those of the antenna device 1 according to the first embodiment.

As shown in FIG. 5A, the curved surface of the battery pack 21 is a surface of a corner portion that is chamfered in a round shape by intersecting three surfaces that are orthogonal to each other. Since the corner portion has the XY plane S _XY , the YZ plane S _YZ, and the ZX plane S _ZX , the stretchable sheet 11 also has these three surfaces. FIG. 5B shows a state in which the flat stretchable sheet 11 is attached along the outer surface of the corner portion of the battery pack 21.

  The stretchable sheet 11 provided along the corner portion of the battery pack 21 has a curved surface that curves in a plurality of directions, and the antenna coil 12 also has a three-dimensional pattern along the curved surface. As in the first embodiment, the direction of the magnetic flux φ penetrating the central portion of the antenna coil 12 is a normal direction perpendicular to the curved surface formed by the antenna coil 12, and therefore the direction of the magnetic flux φ should be widened. Can do. Therefore, the directivity of the antenna coil 12 can be expanded.

  Thus, also in this embodiment, since the battery pack 21 of the portable electronic device in which the antenna is incorporated is used as a support, the directivity of the antenna can be expanded without preparing a dedicated support.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Needless to say, it is included in the range.

  For example, in the above-described embodiment, the case where the casing or the battery pack of the portable electronic device is used as the support has been described. However, the present invention is not limited to these cases, and other members constituting the portable electronic device are used. It may be used as a support.

1-3 Antenna device 10 Support body 10a Curved surface 11 of support body Elastic sheet 12 Antenna coil 13 Resin pattern 15 Cu film 16 Cover layer 20 Housing 21 Battery pack

Claims (4)

A support having a curved surface;
An elastic sheet provided along the curved surface of the support;
An antenna device comprising: an antenna coil provided on a surface of the stretchable sheet.   The antenna device according to claim 1, wherein the curved surface has a dome shape or a chamfered corner shape.   The antenna device according to claim 1, wherein the support is a casing of a portable electronic device, and the curved surface is an inner surface of a corner portion of the casing.   The antenna device according to claim 1, wherein the support is a battery pack of a portable electronic device, and the curved surface is a surface of a corner portion of the battery pack.

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