JP2012105451A - Antenna, electric power transmission device, and electric power reception device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna capable of coping with electric power transmission and various communications in a high-frequency band from several megahertz to tens of megahertz, having a stable electric power transmission function, and simultaneously reducing a radiation noise radiated from the antenna to exterior of an electric power transmission device at charging, and to provide an electric power transmission device and an electric power reception device using the antenna.SOLUTION: An antenna is used in a non-contact electric power transmission and communication system that performs non-contact electric power transmission and communication between an electric power transmission device and an electric power reception device via the antenna. The antenna has a complexed planar coil 10 consisting of: a first terminal 13; a first planar coil 11 wound clockwise using the first terminal 13 as one end; a second terminal 14 provided at an end edge of the first planar coil 11; a second planar coil 12 wound anti-clockwise using the second terminal 14 as one end; and a third terminal 15 provided at an end edge of the second planar coil 12.

Description

  The present invention relates to a system that performs non-contact power transmission between a power transmission device and a power reception device, and in particular, a power reception device provided in a portable device such as a mobile phone, a headset, a digital camera, and a digital video, and a non-connection to the power reception device. The present invention relates to an antenna suitable for a power transmission device that supplies or charges a contact, and a power transmission device and a power reception device using the antenna.

  In a non-contact power transmission system using electromagnetic induction, coils are installed in a power receiving device such as a charging device and a power receiving device such as a portable device, and power is transmitted by electromagnetic induction between those coils. ing. A simple planar coil is used as an antenna for power transmission / reception and data communication between a thin non-contact information recording medium such as a non-contact IC card and a reader / writer, or between a small portable device and a power transmission device. Has been put to practical use. 5A and 5B are diagrams showing an example of a conventional antenna using a planar coil. FIG. 5A is a plan view and FIG. 5B is a front view. A planar coil 23 made of a conductive wire pattern is formed on a magnetic substrate 24 serving as a coil yoke.

  However, when a simple planar coil as shown in FIG. 5 is used as an antenna, there is a problem that the antenna is easily influenced by the environment outside the power transmitting device and the power receiving device on which the antenna is mounted. When power is transmitted / received in an external environment, there is a problem that loss occurs or noise from outside tends to be received, so that power supply is not stable and communication is not stable. For this reason, in order to perform stable power supply, it is necessary to realize an antenna having a stable power transmission function regardless of the surrounding environment.

  In addition, when performing power transmission operations such as charging, a magnetic field is generated from the antenna with a large amount of power, and there is a problem of radiating noise to the surroundings due to the magnetic field. To prevent this, the magnetic flux emitted from the antenna It is necessary to keep the spread within the smallest possible range. By reducing the spread of the magnetic flux from the antenna, it is difficult to be affected by the external environment, and an effect of realizing a stable power transmission function can be obtained.

  In order to increase the electromagnetic coupling efficiency with the power receiving device, the antenna configuration in which the spread of the magnetic flux from the antenna of the charger is suppressed to a small value is described in Patent Document 1. FIG. 6 is a perspective view of the coil antenna described in Patent Document 1, and FIG. 7 is a configuration diagram illustrating electromagnetic coupling between the charger described in Patent Document 1 and the power receiving device side inside the electronic timepiece.

  As shown in FIG. 6, in Patent Document 1, in a charger for an electronic timepiece, a pair of charging coils 40 and 41 are arranged on a coil yoke 42, and currents flowing in opposite directions are caused to flow through the two charging coils. The direction of the formed magnetic field is configured to be reversed. As a result, as shown in FIG. 7, leakage of magnetic flux during charging is reduced by electromagnetic coupling with the power receiving coil 46 of the electronic timepiece 45, and charging efficiency is increased.

JP-A-1-23730

  An antenna used for sharing power transmission and data communication of a small portable device can perform non-contact power transmission through electromagnetic coupling between antennas of a power transmission / reception device, and at the same time is usually used for RFID or the like. It must be applicable to communication in the 56 MHz band. That is, the antenna for this purpose can be reduced in size and thickness, and must have a low loss in a high frequency band.

  In addition, as described above, when power of several watts or more is transmitted, since there is a concern that the mobile device may malfunction if the radiation noise radiated from the antenna to the inside of the mobile device is large, suppress the radiation noise Therefore, it is desirable that the leakage of magnetic flux from the antenna is small.

  However, the coil antenna of the conventional charging device shown in FIG. 6 cannot be used for power transmission in the high frequency band as described above. Since it is intended only for charging at a frequency of about 1 kHz, when used in a high frequency band of several MHz to several tens of MHz, the effect of improving charging efficiency as described in Patent Document 1 cannot be obtained. Further, the coil antenna of FIG. 6 cannot be applied to high frequency band communication. For use as an antenna for power transmission or reception of small portable devices, and as an antenna for communication, both devices should preferably be planar coil antennas, and coil yokes should also be selected from suitable materials with low loss in the high frequency band. There is a need to.

  It is also desirable to be applicable to many types of reader / writers that are commercially available. That is, it is desirable to have an antenna configuration that enables communication with an RFID tag used as a wide variety of contactless communication recording media and an antenna used in an IC card.

  The present invention has been made to solve the above-described problems of the prior art, and the object of the present invention is to support non-contact power transmission and various communications in a high frequency band of several MHz to several tens of MHz. An object of the present invention is to provide an antenna that has a stable power transmission function and can simultaneously reduce radiation noise radiated from the antenna to the outside of the power transmission device during charging, and a power transmission device and a power reception device using the antenna.

  In order to solve the above-described problems, an antenna according to the present invention is an antenna used in a non-contact power transmission and communication system that performs non-contact power transmission and communication between a power transmission device and a power reception device via the antenna. The first terminal, the first planar coil wound clockwise with the first terminal as one end, the second terminal provided at the end of the first planar coil, and the second terminal A second planar coil wound counterclockwise at one end and a third planar terminal provided at the end of the second planar coil, or a first planar terminal, and the first terminal A first planar coil wound counterclockwise with a terminal as one end, a second terminal provided at the end of the first planar coil, and a second coil wound clockwise with the second terminal as one end And a second coil provided at the end of the second planar coil. And having a composite planar coil consisting of a terminal.

  Here, a yoke made of a magnetic material may be disposed on one side of the composite planar coil, or an electromagnetic wave shielding plate may be disposed on one side of the composite planar coil.

  A plurality of the composite planar coils may be arranged.

  The power transmission device according to the present invention uses the antenna according to the present invention.

  Here, when performing non-contact communication with the power receiving apparatus, the directions of the currents flowing through the first planar coil and the second planar coil are both clockwise or counterclockwise. May be set.

  A power receiving device according to the present invention uses the antenna according to the present invention.

  When an antenna according to the present invention is used in a power transmission device and a power reception device and power is transmitted from the power transmission device with the antennas between the two devices facing each other, current flows from the first terminal of the composite planar coil to the second terminal. The magnetic flux generated from the antenna passes through the two coils constituting the composite planar coil in opposite directions to form the composite planar coil on the power receiving device side. Magnetic flux is generated in the direction of rotation through the two coils. For this reason, since magnetic flux is concentrated only in the vicinity of the antenna, radiation noise to the outside is suppressed, and malfunction of peripheral electronic devices can be prevented. When data transmission is performed from a power transmission device or a power reception device, a magnetic field having a similar direction is formed but communication is performed.

  According to the present invention, the antenna of the present invention is used for a power transmission side device such as a reader / writer so that current flows from the first terminal and the third terminal to the second terminal during communication, or By using it so that it flows from the second terminal to the first terminal and the third terminal, the directions of the magnetic fluxes generated from the two coils become the same direction, and with the generally used RFID information recording medium Communication between them is possible.

  Moreover, in the antenna of the present invention, by arranging a yoke made of a magnetic material on the back of the composite planar coil, the magnetic flux generated from the antenna is confined in a narrower region, further improving the power transmission efficiency and further reducing the radiation noise. Can be planned. Further, it is possible to further reduce the radiation noise by arranging an electromagnetic wave shielding plate on the back surface of the composite planar coil.

  As described above, according to the present invention, in a high frequency band of several MHz to several tens of MHz, it is possible to cope with non-contact power transmission and various communications, and has a stable power transmission function. An antenna capable of reducing radiation noise radiated to the outside, and a power transmitting device and a power receiving device using the antenna are obtained.

It is a figure which shows the structure of 1st Embodiment of the antenna by this invention, Fig.1 (a) is a top view, FIG.1 (b) is a front view. FIG. 2A is a schematic diagram for explaining the operation of the antenna according to the present invention, and FIG. 2A is a diagram illustrating a composite planar coil of the power transmission device in which the antenna of the present embodiment is disposed on the power transmission device side and the power reception device side to face each other. FIG. 2B is a schematic diagram seen from the front showing the flow of magnetic flux when a current is passed between the first terminal and the third terminal. FIG. 2B shows the antenna of this embodiment arranged on the power transmission device side. The front surface shows the flow of magnetic flux when the direction of the current flowing through the first planar coil and the second planar coil is set to be both counterclockwise and the FRID antenna is disposed facing the power receiving device side. FIG. FIG. 3 is a diagram showing a simulation result of a distribution of magnetic flux generated from an antenna during power transmission, FIG. 3A is a diagram showing a result of the antenna of the present invention, and FIG. The top view which shows the structure of 2nd Embodiment of the antenna by this invention. It is a figure which shows an example of the antenna by the conventional planar coil, Fig.5 (a) is a top view, FIG.5 (b) is a front view. The perspective view of the coil antenna described in patent document 1. FIG. The block diagram which shows the electromagnetic coupling of the charger described in patent document 1, and the power receiving device side inside an electronic timepiece.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1A and 1B are diagrams showing a configuration of a first embodiment of an antenna according to the present invention. FIG. 1A is a plan view and FIG. 1B is a front view. As shown in FIG. 1, the antenna according to the present embodiment is an antenna used in a non-contact power transmission and communication system that performs non-contact power transmission and communication between a power transmission device and a power reception device via the antenna. A first terminal 13; a first planar coil 11 wound clockwise with the first terminal 13 as one end; a second terminal 14 provided at the end of the first planar coil 11; The composite planar coil 10 includes a second planar coil 12 wound counterclockwise with the second terminal 14 as one end and a third terminal 15 provided at the end of the second planar coil 12. .

  The composite planar coil 10 is fabricated on a planar substrate 16 such as an FPC substrate or an FR-4 substrate using a conductor wire pattern. Alternatively, the composite planar coil 10 can be manufactured by winding. Moreover, it is desirable that the first planar coil 11 and the second planar coil 12 have the same diameter and the same number of turns, and are adjusted so as to generate the same degree of magnetic flux.

  In the antenna of the present embodiment, a yoke 17 made of a magnetic material is disposed on the back surface of the composite planar coil 10 (in this embodiment, the back surface of the planar substrate).

  As this magnetic material, a material having a low loss even in a high frequency band such as NiZn ferrite is desirable. Moreover, the composite material which combined the magnetic material with a several different magnetic permeability may be sufficient.

  Further, a shield material serving as an electromagnetic wave shielding plate may be disposed on the back surface of the yoke 17.

  Next, a specific example of the antenna according to this embodiment will be described.

  In FIG. 1, the first planar coil 11 and the second planar coil 12 each have an outer shape of 20 mm × 20 mm, the coil winding pattern width is 0.7 mm, and the coil winding gap is 0. The composite planar coil 10 formed by forming 3 mm and 3 turns and connecting the first planar coil 11 and the second planar coil 12 in series was formed on an FPC board having an outer shape of 40 mm × 20 mm.

  The yoke 17 is made of NiZn ferrite and has an outer shape of 40 mm × 20 mm and a thickness of 0.3 mm.

  Next, the operation of the antenna of this embodiment will be described. FIG. 2 is a schematic diagram for explaining the operation of the antenna according to the present invention. FIG. 2A is a diagram illustrating the antenna according to the first embodiment arranged on the power transmission device side and the power reception device side to face each other. It is the schematic diagram seen from the front which shows the flow of the magnetic flux at the time of flowing an electric current between the 1st terminal and 3rd terminal of the compound plane coil of an apparatus. 2A, the magnetic flux generated in the antenna 31 on the power transmission device side proceeds from the first planar coil 11 to the yoke 17, from the yoke 17 to the second planar coil 12, and further to the magnetic flux. Advances from the second planar coil 12 to the first planar coil 36 of the opposing antenna 32 on the power receiving device side, passes through the second planar coil 37 through the yoke 17, and the first planar surface on the power transmitting device side. It occurs in the direction of rotation to the coil 11 and so on.

  In FIG. 2B, the antenna of the first embodiment is arranged on the power transmission device side so that the directions of the currents flowing through the first planar coil 11 and the second planar coil 12 are both counterclockwise. FIG. 6 is a schematic view seen from the front showing the flow of magnetic flux when the RFID antenna is placed opposite to the power receiving device. That is, in FIG. 1, the second terminal 14 is used so that a current flows from the first terminal 13 to the third terminal 15. In this case, as shown in FIG. 2B, the magnetic fluxes emitted from the first planar coil 11 and the second planar coil 12 are in the same direction and are generated in the direction of the RFID antenna 33 as indicated by arrows. Therefore, it is possible to obtain a magnetic flux distribution similar to that of an antenna used for communication with a non-contact communication medium for RFID.

  When the antenna according to the present embodiment is used for both the power transmission device and the power reception device, the power transmission efficiency was 90%. Since the power transmission efficiency of the antenna having the conventional configuration was 91%, comparing the antenna of this embodiment with the conventional antenna, it can be seen that the antenna of this embodiment can obtain the same efficiency as the conventional antenna. . However, in the antenna of the present embodiment, as described below, the magnetic flux generated from the antenna can be confined in a narrow region, and the radiated noise radiated from the antenna to the outside of the power transmission device during charging is compared with the conventional antenna. Can be reduced.

  FIG. 3 is a diagram illustrating a simulation result of the distribution of magnetic flux generated from the antenna during power transmission. FIG. 3 (a) is a diagram showing a result of the antenna of the present invention, and FIG. 3 (b) is a diagram showing a result of the conventional antenna. The magnetic flux distributions when the same antenna is disposed opposite to the power transmitting device and the power receiving device are shown. That is, in FIG. 3A, the antenna 31 on the power transmission device side and the antenna 32 on the power reception device side of the present invention are arranged in the same manner as in FIG. 2A, and FIG. This is a case where the antennas 34 and 35 are arranged facing each other. As apparent from FIG. 3, the leakage flux from the yoke is large in the conventional antennas 34 and 35, whereas the leakage flux is reduced in the antenna 31 on the power transmission device side and the antenna 32 on the power reception device side of the present invention. I understand that. This indicates that the antenna of the present invention has an effect of reducing noise generated from the antenna and reducing the influence of the external environment on the antenna as compared with the conventional antenna. When a metal plate such as a circuit board is brought close to the back of the antenna being charged, the efficiency of the conventional antenna is reduced by 8% and the power transmission efficiency is 83%. However, the efficiency of the antenna of this embodiment is not reduced. The power transmission efficiency was 86%.

  FIG. 4 is a plan view showing the configuration of the antenna according to the second embodiment of the present invention. The antenna according to the present embodiment has the antenna of the first embodiment shown in FIG. 1 as a unit antenna, and as shown in FIG. It is configured. Here, although the number of unit antennas is nine, the number of unit antennas can be an arbitrary value of 2 or more, and the unit antenna arrangement method can be arbitrarily designed.

  The antenna of this embodiment can be applied to both the power transmission device and the power reception device, and the number of unit antennas of the power reception device can be smaller than that of the power transmission device.

  When the antenna of the present embodiment is used for a power transmission device, the maximum transmitted power of the power transmission device can be adjusted by the number of unit antennas constituting the antenna. For example, if it is possible to transmit 1 W of power per unit antenna, a power transmission device including nine unit antennas can transmit power up to a maximum of 9 W.

  In addition, the power transmission device using the antenna according to the present embodiment can simultaneously transmit power to a plurality of power receiving devices as long as the total transmitted power is equal to or less than the maximum transmitted power.

  Further, the maximum received power of the power receiving apparatus can be adjusted by the number of unit antennas constituting the antenna. For example, if it is possible to receive 1 W of power per unit antenna, a power receiving apparatus including four unit antennas can receive power up to a maximum of 4 W.

  Although the embodiments and examples of the present invention have been described above, the present invention is not limited to these embodiments and examples, and members, configurations, and respective parts are within the scope of the present invention. It is possible to change the shape or the like. For example, the configuration of the antenna is not limited to that shown in FIG. 1, and various modifications such as omitting some of the components, adding other components, and changing the connection relationship are possible. It is.

DESCRIPTION OF SYMBOLS 10 Composite plane coil 11, 36 1st plane coil 12, 37 2nd plane coil 13 1st terminal 14 2nd terminal 15 3rd terminal 16 Planar substrate 17 Yoke 23 Planar coil 24 Magnetic substrate 31 Power transmission apparatus Side antenna 32 Power receiving device side antenna 33 RFID antennas 34 and 35 Conventional antennas 40 and 41 Charging coil 42 Coil yoke 45 Electronic timepiece 46 Power receiving coil

Claims (7)

  An antenna used in a non-contact power transmission and communication system that performs non-contact power transmission and communication between a power transmitting device and a power receiving device via an antenna, wherein the first terminal and the first terminal are A first planar coil wound clockwise as one end, a second terminal provided at the end of the first planar coil, and a second plane wound counterclockwise with the second terminal as one end A composite planar coil comprising a coil and a third terminal provided at the end of the second planar coil, or a first terminal and a first terminal wound counterclockwise with the first terminal as one end A planar coil, a second terminal provided at the end of the first planar coil, a second planar coil wound clockwise with the second terminal as one end, and an end of the second planar coil And a composite planar coil comprising a third terminal provided on the Antenna to be.   The antenna according to claim 1, wherein a yoke made of a magnetic material is disposed on one side of the composite planar coil.   The antenna according to claim 1 or 2, wherein a shielding plate for blocking electromagnetic waves is disposed on one surface of the composite planar coil.   The antenna according to any one of claims 1 to 3, wherein a plurality of the composite planar coils are arranged.   A power transmission device using the antenna according to any one of claims 1 to 4.   When non-contact communication is performed with the power receiving device, the direction of the current flowing through the first planar coil and the second planar coil is set to be clockwise or both counterclockwise. The power transmission device according to claim 5.   A power receiving device using the antenna according to any one of claims 1 to 4.

Images