The present invention generally relates to a non-contact charging device for transmitting electricity from a feeder/charger side to a battery/terminal side in a non-contact manner, and, in particular, to an antenna sheet for a non-contact charging device for feeding electricity through a magnetic field coupling and a charging device using the antenna sheet.
Charging with respect to a secondary battery usable for an electric source of a device, such as a mobile phone, a mobile terminal, an electric shaver, or an electric toothbrush, has heretofore been performed by causing current to flow by an electrically-conductive contact between a contact point of a charger and a device-side contact point wired from a battery pack serving as the secondary battery.
In recent years, there has been increased a type which performs charging with respect to the secondary battery of such a device or the like in a non-contact manner.
The Patent Document 1 discloses a non-contact charging device for feeding electricity in a non-contact state by electromagnetic induction action. The device has a power transmitting side and a power receiving side each comprising a plurality of coils arranged on a plate-like soft magnetic material, wherein the coils on the power transmitting side and the coils on the power receiving side are arranged in a spaced-apart and opposed relation so as to allow magnetic fluxes generated by adjacent coils on each side to be respectively directed in reverse directions, and wherein the plate-like soft magnetic material on the power receiving side is arranged to come contact with a battery can directly or via an insulating member.
In addition, the Patent Document 2 describes a non-contact power transmission device for feeding electricity from power transmission coils to power reception coils by electromagnetic induction. The device is capable of preventing occurrence of a leakage magnetic flux, and of accommodating battery charges for a plurality of electronic devices having different electricity requirements by a single power transmission device. The device comprises a plurality of power transmission coils 11, 12 arranged in an approximately concentric pattern, and is configured to drive only a power transmission coil having an outer shape closest to an outer shape of a power reception coil 21 and a power transmission coil arranged thereinside. Accordingly, the device provides an effect of preventing an occurrence of the leakage magnetic flux even when the electricity is transmitted to the power reception coils having different outer shapes by a single power transmission device.
However, such a non-contact type charging device or power transmission device performs charging or power transmission through electromagnetic coupling involved with electromagnetic induction action, so that the arrangement on the power transmitting and receiving sides is limited. That is, there has been a problem that the charging efficiency becomes extremely degraded unless the power transmission coils and the power reception coils are arranged in an approximately opposed relation at an extremely close range.
On the other hand, yet among the non-contact type charging device, there is a device which feeds electricity on a charger side to a rechargeable battery side by a magnetic field coupling of a primary coil (power transmission coil) and a secondary coil (power reception coil) (the Patent Document 3).
Specifically, the Patent Document 3 discloses a non-contact charging device comprising: a charger 1; and a wireless communication device 2 having a charging battery 210. The charger 1 is provided with a primary coil 103 and means 104, 105 for feeding AC power to the primary coil. The wireless communication device 2 is provided with a secondary coil 212 in magnetic field coupling with the primary coil 103, and means 211 for using an electromotive force generated in the secondary coil as charging power for the charging battery 210. The non-contact charging device is configured to perform charging by feeding the electricity of the charger 1 to the charging battery 210 through magnetic field coupling between the primary coil 103 and the secondary coil 212. The non-contact charging device is provided with switches 106, 107, 213 for stopping the feeding of electricity to the primary coil 103, and when it is required to make or receive a call during charging of the wireless communication device, the switches are operated to stop the charging to eliminate an influence of a magnetic force exerted on the wireless communication device, thereby allowing the wireless communication device to be lifted up from the charger by a slight force and used.
However, as described above, the device disclosed in the Patent Document 3 is required, when it is required to make or receive a call during charging of the wireless communication device, to stop the charging to eliminate an influence of a magnetic force exerted on the wireless communication device, allowing the wireless communication device to be lifted up from the charger by a slight force because the magnetic force between the primary coil and the secondary coil is extremely large.
Further, the charger 1 has a concave portion provided in a base case for feeding electricity to the wireless communication device, in which the wireless communication device can be inserted. The concave portion is configured to allow the wireless communication device to be placed on the charging device in a standing state, and thus, the arrangement relation between the power transmitting side and the power receiving side is limited.
Patent Document 1: JP 11-103531A
Patent Document 2: JP 2012-060812A
Patent Document 3: JP 08-019185A
It is therefore an object of the present invention to provide an antenna sheet for a non-contact charging device and a charging device using the antenna sheet, wherein the antenna sheet is configured to allow for a high degree of freedom in regard to the arrangement of a charger side and a battery side during power charging.
According to the present invention, there is provided an antenna sheet for a non-contact charging device, usable as a transmitting-side resonator for a transmitting-side device or a receiving-side resonator for a receiving-side device, the antenna sheet comprising: a substrate; and a coil-shaped antenna formed on the substrate, the coil-shaped antenna being configured to function as a pickup coil operable to resonate at a resonant frequency f, when a resonance capacitor is set to have a capacitance C.
In the antenna sheet, the resonant frequency f is 13.56 MHz, the transmitting-side resonator comprises a resonance capacitor having a capacitance of 1 to 5 pF, and the receiving-side resonator comprises a resonance capacitor having a capacitance of 70 to 100 pF.
In the antenna sheet, the resonant frequency f is 6.78 MHz, the transmitting-side resonator comprises a resonance capacitor having a capacitance of 8 to 20 pF, and the receiving-side resonator comprises a resonance capacitor having a capacitance of 70 to 120 pF.
According to the present invention, there is also provided a non-contact charging device comprising: a transmitting-side antenna sheet obtained by adhering a first substrate on a first magnetic sheet with an adhesive, forming a resonance coil on the first substrate, and burying a feed coil in the adhesive; and a receiving-side antenna sheet obtained by adhering a second substrate on a second magnetic sheet with an adhesive, and forming a reception coil on the second substrate.
In the non-contact charging device, each of the resonance coil and the reception coil has a resonant frequency of 13.56 MHz, the transmitting-side antenna sheet comprises a resonance capacitor having a capacitance of 1 to 5 pF, and the receiving-side antenna sheet comprises a resonance capacitor having a capacitance of 70 to 100 pF.
In the non-contact charging device, each of the resonance coil and the reception coil has a resonant frequency of 6.78 MHz, the transmitting-side antenna sheet comprises a resonance capacitor having a capacitance of 8 to 20 pF, and the receiving-side antenna sheet comprises a resonance capacitor having a capacitance of 70 to 120 pF.
The present invention provides an effect that there can be provided an antenna sheet for a non-contact charging device and a charging device using the antenna sheet, wherein the antenna sheet is configured to allow for a high degree of freedom in regard to the arrangement of a charger side and a battery side during power charging, and further, that electricity on the transmitting side can be simultaneously fed to a plurality of devices on the receiving side.
Embodiments of an antenna sheet for a non-contact charging device and a charging device using the antenna sheet according to the present invention will now be described with reference to the figures.
Hereinafter, the feed sheet 101, the reception sheet 102 and the resonance sheet 103 are also referred to as a feeding antenna sheet 101, a receiving antenna sheet 102 and a resonating antenna sheet 103, respectively.
Further, the feed coil 1012, the reception coil 1022 and the resonance coil 1032 are also referred to as a feed antenna 1012, a reception antenna 1022 and a resonance antenna 1032, or as feed coil-shaped antenna 1012, a reception coil-shaped antenna 1022 and a resonance coil-shaped antenna 1032, respectively.
In the non-contact charging device in
Each coil-shaped antenna formed on the substrate has a role of transmitting electricity fed from a feeding device (not illustrated) from a transmitting side to a receiving side. In
In the non-contact charging device in
The antenna sheet 200 may also be used as an antenna sheet on the transmitting side (as described below in
For the adhesive 203, it is possible to use a thermoplastic resin such as vinyl acetate or vinyl chloride, or a solvent having a thermoplastic resin component.
For the magnetic sheet 204, it is possible to use a magnetic sheet comprising a flat soft magnetic material powder and a resin.
The material for the adhesive 203 or the magnetic sheet 204 is as described above.
In an implementation, the gap layer 283 is filled with Styrofoam.
A difference between the antenna sheets 250 and 280 in terms of their functional effects will now be described. According to an experiment performed by the Inventors, under the condition of 6.78 MHz of resonance frequency in the resonance coil 251, better transmitting efficiency is obtained when the distance between the feed coil and the resonance coil is set closer as with the antenna sheet 250, while under the condition of 13.56 MHz of resonance frequency in the resonance coil 251, better transmitting efficiency is obtained when the gap layer (with a thickness of about 5 mm) is provided between the feed coil 255 and the resonance coil 251 (or between the substrates 282a and 282b) as with the antenna sheet 280.
That is, the transmitting-side device 501 comprises an antenna sheet mounted on the transmitting-side control circuit board 5011, wherein the antenna sheet has a substrate 5014 adhered on a magnetic sheet 5012 with an adhesive 5013 and a transmitting coil (-shaped antenna) 5015 formed on the substrate 5014 by etching or the like. Likewise, the receiving-side device 502 comprises an antenna sheet mounted on the receiving-side control circuit board 5021, wherein the antenna sheet has a substrate 5024 adhered on a magnetic sheet 5022 with an adhesive 5023 and a reception coil (-shaped antenna) 5025 formed on the substrate 5024 by etching or the like. Then, in
The transmitting-side device 551 comprises a similar antenna sheet to that illustrated in
Then, in
In
In
Further, in
For convenience of explanation, three capacitors are illustrated in
Further, the capacitor elements illustrated in
As illustrated in
Further, the present invention has a great advantage that the electricity on the transmitting-side can be simultaneously supplied to a plurality of receiving-side devices (as an example, 1002c, 1002d and 1002e in
As stated above, the antenna sheet for the non-contact charging device and the charging device using the antenna sheet according to the present invention allow for non-contact charging with high degree of freedom in arrangement. The followings will describe in detail a resonance condition etc. for enabling such a charging.
The basic operation of the non-contact charging device is generally to feed electricity generated in a power transmission device on a transmitting side from a transmitting-side device to a receiving-side device in a non-contact manner by coupling the magnetic fields generated at a transmitting-side resonator for the transmitting-side device having a predetermined resonance frequency f1 and at a receiving-side resonator for the receiving-side device having a predetermined resonance frequency f2 in an electromagnetic field having a frequency environment of 400 kHz to 20 MHz.
Generally, a configuration of the power transmission device comprises a transmitting-side resonator, a transmitter, a power amplifier, a directional coupler, a bandpass filter (as an example, a BPF for travelling wave, a BPF for reflected wave, or the like), a distributor (as an example, a distributor for travelling wave, a distributor for reflected wave, or the like), a computing unit, a low-pass filter, a phase-change detector, an amplitude-difference detection circuit, a smoothing capacitor, a link coil, an impedance-variable element, a control section and the like. However, since the power transmission device in the present invention can employ known components, any detailed description of the power transmission device will be omitted here.
Then, at the transmitting-side resonator, the relation of the following formula (1) is satisfied:
where f1 is a resonance frequency, L1 is an inductance of a pickup coil, and C1 is a capacitance of a resonance capacitor.
Further, at the receiving-side resonator, the relation of the following formula (2) is satisfied:
where f2 is a resonance frequency, L2 is an inductance of a pickup coil, and C2 is a capacitance of a resonance capacitor.
The electric current extracted in a non-contact manner in the receiving-side device at a pickup coil L2 by electromagnetic induction is controlled by the control section (not illustrated) as a constant current, and subjected to impedance conversion as necessary to feed electricity to a load.
Based on this basic principle, the present invention sets two types of resonance frequencies: 13.56 MHz and 6.78 MHz, and variously sets the resonance capacitor C1 of the transmitting-side (resonance) coil and the resonance capacitor C2 of the receiving-side coil (for which two types including Type 1 and Type 2 are prepared), to thereby verify a condition in which the effect of the present invention as described above can be sufficiently provided. The results are summarized in the Table 1 below.
The receiving-side coil (Type 1) has an outer shape of 60 mm×60 mm in, the coil has a thickness L of 1 mm, and the coil wires have a spacing S of 0.5 mm therebetween. On the other hand, the receiving-side coil (Type 2) has an outer shape of 30 mm×40 mm in, the coil has a thickness L of 0.4 mm, and the coil wires have a spacing S of 0.2 mm therebetween. The number of turns of the coil is set to the number by which an inductance satisfying a resonance frequency with respect to the capacitance of the resonance capacitor can be obtained, respectively.
Further, in the verification, a condition in which higher power efficiency is obtained is also examined by gluing various types of magnetic sheets to the receiving-side antenna sheet.
As a result of verification, in the case where the magnetic sheet is not used and the resonance frequency is 13.56 MHz, good power feeding efficiency is obtained when the capacitor of the resonance coil has a capacitance C1 of 1 to 5 pF, and the capacitor of the reception coil has a capacitance of 70 to 100 pF for both Type 1 and Type 2.
On the other hand, in the case where the resonance frequency is 6.78 MHz, good power feeding efficiency is obtained when the capacitor of the resonance coil has a capacitance C1 of 8 to 20 pF, and the capacitor of the reception coil has a capacitance of 70 to 120 pF for both Type 1 and Type 2.
In the case where the magnetic sheet is used, good power feeding efficiency is obtained when the magnetic sheet has a thickness of approximately 70 μm in both of the sheet patterns (
Further, when the magnetic sheet is set to have a thickness of approximately 200 μm, leakage magnetic flux on the receiving side can more strongly be inhibited, and higher power feeding efficiency can be obtained.
For the magnetic sheet, those having thickness of approximately 10 to 500 μm can be extensively used.
The relation between the thickness of the magnetic sheet and the feeding efficiency will now be described. In the order of the above experiment, it is considered that the magnetic sheet having larger thickness provides higher feeding efficiency. Further, if the magnetic sheet is thicker, the leakage magnetic flux can be reduced, so that an effect of reducing a negative impact on the control circuit board can be promised.
Further, the thicker the magnetic sheet is, the greater the impact on the coil becomes, resulting in a tendency that the resonance frequency is reduced. Accordingly, in the case of providing a “magnetic body-integrated coil” to which the present invention is applied, the coil can be designed by taking into account the frequency shift caused by the magnetic sheet from a design phase thereof. Thus, the handling becomes advantageously easy relative to a case where a user separately purchases and combines the coil and the magnetic sheet.
According to the present invention, a plurality of transmitting-side devices can be used. Referring to
Transmission efficiency from the transmitting-side device to the receiving-side device in each of the arrangements of
In this way, when a plurality of transmitting-side devices are used, the receiving-side device can be simultaneously fed with electricity from all the transmitting-side devices, and for example, when a large number of transmitting-side devices are arranged planarly or sterically, the degree of freedom in arrangement illustrated in
In addition, a condition etc. which is obtained by the Inventor through the experiment will now be noted. Where the outer diameter of the reception coil=0, the distance between the receiving-side device and the transmitting-side device is preferably not less than 0 and not more than α, more preferably not less than 0 and not more than 0.75×α, and yet more preferably not less than 0.25×α and not more than 0.5×α. In this case, the outer diameter of the reception coil α is α=(long side length of outer-most side+short side length of outer-most side)/2 only if the ratio of long side: short side=1:1 to 2:1 in the case of rectangle. Further, for the relation between the outer diameter of the reception coil a and the outer diameter of the transmitting coil β, the relation of α>β/3 and α<β×3 holds.
Number | Date | Country | Kind |
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2012-110940 | May 2012 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2013/063435 | 5/14/2013 | WO | 00 |