JP2012157079A - Antenna device - Google Patents

Abstract

An object of the present invention is to provide a small and low-cost antenna device for any mobile phone by arranging an antenna device on a battery pack.
The present invention includes a battery pack (6) having a metal surface, a magnetic body (3) formed on the battery pack (6), and a coil (2) wound around the magnetic body (3). The opening of the coil 2 communicates by obtaining an eddy current generated in the battery pack 6 with one facing the outside of the battery pack 6 and the other facing the center of the battery pack 6.
[Selection] Figure 2

Description

  The present invention is an RF-ID, that is, a wireless communication medium processing device that performs communication with a wireless communication medium such as an IC card or an IC tag, or an antenna device used for the wireless communication medium itself, and includes an electromagnetic induction method and a microwave method. The present invention relates to a thin and low-cost antenna device.

  Conventionally, in an RF-ID, that is, a non-contact type IC card or IC tag, for example, as shown in FIG. 4, a magnetic flux from a reader / writer (hereinafter referred to as R / W) as an external device is passed through the loop antenna 101. Thus, communication is performed between the R / W and the antenna device 100 by generating a current in the loop antenna 101 and modulating the current generated in the loop antenna 101 (see, for example, Patent Document 1).

Japanese Patent Laying-Open No. 2005-210213

  However, when the antenna device is downsized, it is necessary to make the antenna into a chip. When the antenna is made into a chip, a coil is wound on a magnetic sheet to make the chip antenna fair. And it is necessary to install a back metal plate in the lower part of the chip antenna in order to increase the level of signals to be transmitted and received. However, when installing in a small communication device such as a mobile phone, the shape of the chip antenna must be changed variously according to the shape or circuit arrangement of the mobile phone or the like incorporating the chip antenna. It was necessary to change the shape of the metal plate to be installed according to the shape of the chip antenna to be installed. As a result, chip antennas have become a small variety of products, and it has been difficult to reduce the cost of chip antennas.

  In view of the above problems, the present invention provides a small antenna device that communicates using an electromagnetic induction method or a microwave method, and that is the same shape and small in any shape communication device, Furthermore, it aims at providing a low-cost antenna apparatus.

  To achieve the above object, the present invention comprises a battery pack having a metal surface, a magnetic body disposed on the metal surface, and a coil wound around the magnetic body, The two openings of the coil are arranged at the end of the metal surface, one of which faces the outside of the metal surface and the other faces the center side of the metal surface, and uses the eddy current generated in the metal surface. The coil performs communication.

  According to the present invention, since the antenna device is arranged on the battery pack that is always provided in a communication device such as a mobile phone, an antenna device having the same shape, size and cost can be obtained in any mobile phone. (The shape of the battery pack is standardized by the standard). In addition, by arranging a plurality of antenna devices on the surface of the battery pack of a mobile phone, eddy currents generated on the surface of the battery pack can be picked up efficiently, and the communication characteristics of the antenna device can be improved very easily. Can do.

  Furthermore, since the eddy current can be efficiently generated on the surface of the battery pack by covering the surface of the battery pack of the mobile phone with the copper foil, the effect of improving the communication characteristics of the antenna device can be obtained.

Configuration diagram of an antenna device in an embodiment of the present invention The figure which shows the antenna device and peripheral circuit in the Example of this invention Operational principle diagram of antenna device in an embodiment of the present invention Top view of antenna device in the prior art

  According to the first aspect of the present invention, the battery pack includes a metal surface, a magnetic body disposed on the metal surface, and a coil wound around the magnetic body, the coil Is arranged at the end of the metal surface, and the two openings of the coil use one of the eddy currents generated on the metal surface, one facing the outside of the metal surface and the other facing the center of the metal surface. Then, the antenna device is characterized in that the coil performs communication.

  Thereby, the communication characteristic of the antenna device can be improved very easily.

  According to a second aspect of the present invention, there is provided the antenna device according to the first aspect, wherein a plurality of the coils are provided on the metal surface. Thus, by covering the surface of the battery pack with the copper foil, an eddy current can be efficiently generated on the surface of the battery pack, so that the effect of improving the communication characteristics of the antenna device can be obtained.

  Thereby, the eddy current which generate | occur | produces in a battery pack can be picked up efficiently, and the communication characteristic of an antenna apparatus can be improved easily.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, the configuration and shape of the antenna device 1 of the present invention will be described. FIG. 1 is a configuration diagram of an antenna device 1 according to an embodiment of the present invention.

  The antenna device 1 shown in FIG. 1 has two antenna elements in which a coil 3 is spirally wound on a magnetic body 2, and these two antenna elements are electrically connected to each other. As shown in FIG.

  A cell phone battery pack 6 is provided on the back surface of the antenna unit 4 and accommodates a battery for supplying power necessary for the communication terminal. Reference numeral 5 denotes a conductive wire for connecting the antenna unit 4.

  An antenna element is arranged at a position where an eddy current generated on the battery pack 6 can be efficiently picked up. In the present embodiment, the antenna portion 4 is formed at the end portion of the battery pack 6, but the eddy current is generated more strongly at the end portion than at the central portion of the metal body.

  A chip capacitor 7 is provided at both terminals of the antenna unit 4 of the antenna device 1, and the resonance frequency of the antenna device 1 is adjusted to a predetermined frequency (13.56 MHz). This value is a value determined by the standard, and a value close to the above value must be the resonance frequency.

  Further, each part will be described in detail.

  First, the antenna unit 4 including the magnetic body 2 and the coil 3 will be described.

  As shown in FIG. 1, the antenna unit 4 is formed by winding a coil 3 around a magnetic body 2 in a spiral shape. As a spiral structure, the shape may be circular, substantially rectangular, or polygonal. By adopting a spiral structure, the magnetic flux 10 from the R / W can be sufficiently obtained, and communication between the wireless communication medium and the wireless communication medium processing device by the generation of inductive power and mutual inductance is enabled. . The antenna unit 4 may be a combination of two or more antenna elements. If the number of antenna elements increases, it becomes easier to pick up eddy currents generated on the battery pack 6 of the mobile phone. Communication characteristics are improved.

  Furthermore, the material of the antenna can be appropriately selected from conductive metal wire materials such as gold, silver, copper, aluminum, nickel, metal plate materials, metal foil materials, metal cylinder materials, etc. You may form by wire, metal foil, an electrically conductive paste, plating transcription | transfer, a sputter | spatter, vapor deposition, or screen printing.

  Next, the magnetic body 2 will be described.

  The magnetic material is made of a metal material such as ferrite, permalloy, sendust, or silicon plywood.

  As the magnetic material, soft magnetic ferrite is preferable, and a ferrite powder can be made into a fired body or a high-density ferrite fired body by dry press molding and firing, and the density of the soft magnetic ferrite is 3.5 g / cm 3. The above is preferable. Furthermore, the size of the magnetic body 2 of soft magnetic ferrite is preferably greater than the grain boundary. Moreover, the magnetic body 2 is a rod-like or layer-like one formed with a size of about 3 × 3 × 10 mm.

The soft magnetic ferrite may be made of Ni—ZnO 3, ZnO, NiO, CuO, or Fe 2 O 3, ZnO, MnO, CuO. Furthermore, it may be a single layer of magnetic body 2 of any one of amorphous alloy, permalloy, electromagnetic steel, silicon iron, Fe-Al alloy, and sendust alloy, and it is a laminate of ferrite, amorphous foil, permalloy, electromagnetic steel, and sendust. There may be a laminated body in which various magnetic bodies 2 are combined. When laminating magnetic materials, at least one of resin, ultraviolet curable resin, visible light curable resin, thermoplastic resin, thermosetting resin, heat resistant resin, synthetic rubber, double-sided tape, adhesive layer, or film By the means, the magnetic material is adhered to form a laminated structure.

  Furthermore, the magnetic body 2 of the present invention comprises ferrite, amorphous alloy, permalloy, electromagnetic steel, silicon iron, Fe—Al alloy, Sendust alloy alone or a laminate, resin, ultraviolet curable resin, visible light curable resin, heat It may be coated by at least one means of a plastic resin, a thermosetting resin, a heat resistant resin, a synthetic rubber, a double-sided tape, an adhesive layer, or a film.

  The magnetic body 2 of the present invention is composed of a single layer, a multilayer structure, or a solid piece, and is a resin, an ultraviolet curable resin, a visible light curable resin, a thermoplastic resin, a thermosetting resin, a heat resistant resin, a synthetic rubber, or both surfaces. Coating with at least one of tape, adhesive layer, or film provides high flexibility and durability, high surface resistance, and easy circuit formation by antenna printing or plating on the surface It is.

The magnetic body 2 in this example is obtained by firing Ni—Zn-based ferrite or Mn—Zn-based ferrite material at 800 ° C. to 1000 ° C.

  Furthermore, as the shape of the magnetic body 2, it may be formed in a shape such as a substantially triangular prism, a substantially quadrangular prism, a substantially cylindrical shape, or a substantially spherical shape.

  Next, the conducting wire 5 will be described.

  The conductor 5 is connected to the antenna element as shown in FIG. 2, and any material may be used as long as it is conductive. Examples of the material of the conductor 5 include gold, silver, copper, aluminum, and nickel. Can be appropriately selected from conductive metal wire, metal plate, metal foil, or metal cylinder, etc., such as metal wire, metal foil, conductive paste, plating transfer, sputtering, vapor deposition, or Alternatively, it may be formed by screen printing.

  Next, the battery pack 6 will be described.

  As shown in FIG. 2, the battery pack 6 is installed so as to be on the back surface of the antenna device 1, and the position where the battery pack 6 is installed and the size of the battery pack 6 in the mobile phone are substantially fixed. From this, the antenna device 1 according to the present invention that performs communication by picking up the eddy current generated on the battery pack 6 can produce the antenna device 1 having the same shape in any mobile phone.

  Further, when it is desired to further improve the performance of the antenna device 1, a conductive copper foil or the like may be attached to the surface of the battery pack 6.

  Next, the chip capacitor 7 will be described.

  The chip capacitor 7 is mounted at the end of the loop antenna 2 as shown in FIG. 2, and the resonance point of the resonance frequency of the antenna device 1 is changed by changing the capacitance value of the chip capacitor 7. Can do. Since the chip capacitor 7 is normally 1005 size and the resonance frequency may vary depending on the surrounding environment, a chip capacitor 7 having a small change in capacitance value with respect to the environmental temperature is selected.

  The antenna device 1 is formed with the configuration described above.

  Further, when the antenna device 1 is mounted on a small terminal such as a cellular phone, the antenna device 1 on which the antenna portion 4 is formed is coated with a double-sided tape, an adhesive, an adhesive layer, a resin, or the like. Paste where needed.

  FIG. 2 is a diagram showing a state in which the antenna device 1 and peripheral circuits are connected. The same reference numerals denote the same components as those described in FIG. In FIG. 2, 8 is a rectifier circuit, and 9 is a main chip. The rectifier circuit 8 is for obtaining impedance matching between the antenna device 1 and the main chip 1, and the main chip 9 is for processing transmission / reception signals.

  In the conventional antenna device, communication is performed by capturing the magnetic flux generated from the R / W by the coil of the antenna device and generating a current on the coil.

On the other hand, in the antenna device 1 of the present invention, as shown in FIG. 3, the battery pack 6 is provided with a magnetic flux 10 (see FIG. 3 [1]) emitted from the R / W in a communication device such as a mobile phone. The magnetic flux 10 is received. As a result, a demagnetizing field is generated on the surface of the battery pack 6 and thereby an eddy current 11 is generated (see FIG. 3 [2]). The eddy current 11 is picked up by the antenna device 1 of the present invention for communication. (See FIG. 3 [3]). This is possible because the battery pack 6 is made of metal as described above.

  Since the battery pack 6 of the mobile phone is almost fixed in size and shape and is fixed, the shape of the antenna device 1 of the present invention can be made constant. As a result, it is not necessary to manufacture a small amount of various types of antenna devices 1, so that the cost of the antenna device 1 can be reduced.

  In addition, since the antenna device 1 has a structure in which the coil 3 is simply wound around the magnetic body 2, it is possible to provide a small and inexpensive antenna device 1.

  In order to further improve the performance of the antenna device 1, it is possible to increase the antenna elements on the battery pack 6 or to cover the surface of the battery pack 6 with copper foil. be able to.

  The antenna device of the present invention supplies power and transmission data to a wireless communication medium such as a non-contact IC card or an IC tag stored in a product shelf and acquires the received data from the wireless communication medium by load fluctuation. It is a processing device, and it is necessary to expand the communication range especially for storage shelves that can automatically manage products, books, etc., medicine management other than exhibition shelves, dangerous goods management, valuables management system, etc. It can also be applied to applications.

DESCRIPTION OF SYMBOLS 1 Antenna apparatus 2 Magnetic body 3 Coil 4 Antenna part 5 Conductor 6 Battery pack 7 Chip capacitor 8 Matching circuit 9 Main chip 100 Antenna apparatus 101 Loop antenna

Claims (2)

A battery pack including a metal surface, a magnetic body disposed on the metal surface, and a coil wound around the magnetic body,
The coil is disposed at an end of the metal surface;
One of the two openings of the coil faces the outside of the metal surface, and the other faces the center side of the metal surface.
An antenna device, wherein the coil communicates using eddy current generated on the metal surface. The antenna device according to claim 1, wherein a plurality of the coils are provided on the metal surface.

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