JP6384633B2 - Coil antenna, power feeding device, power receiving device, and wireless power feeding system - Google Patents

Description

  The present invention relates to a coil antenna including a coil conductor, a wireless power feeding system using the coil antenna, a power feeding device and a power receiving device constituting the wireless power feeding system.

  2. Description of the Related Art In recent years, research and development for improving power supply efficiency and reducing the size of devices in a wireless power supply system has become active.

  In the magnetic field coupling type wireless power feeding system, the coil antenna of the power feeding device and the coil antenna of the power receiving device are magnetically coupled in a state where they are arranged close to each other. Therefore, when the positional relationship between the coil antenna of the power feeding device and the coil antenna of the power receiving device changes, the power supply efficiency changes according to the deviation.

  Patent Document 1 discloses a coil antenna in which the spacing between coil conductors of the coil antenna is adjusted in order to suppress fluctuations in power supply efficiency due to the above-described positional deviation. FIG. 9 is a plan view of the coil antenna disclosed in Patent Document 1. FIG. A spiral coil conductor 30 is formed on the insulating substrate 20. The coil conductor 30 has a pattern in which the center side is sparse and the outside is dense.

Japanese Patent No. 5221111

  In the structure in which the coil conductors constituting the coil antenna are provided with the above-described density, the influence of the parasitic capacitance between the coil conductors may be noticeable depending on the position of the connection portion of the coil antenna. In particular, when the winding pattern of the coil conductor is line symmetric and the above-described sparse / dense structure is used, an external circuit is connected to a portion where the coil conductor is “dense”. A large parasitic capacitance is generated in the vicinity. Since the highest potential difference is generated in this connection portion, the self-resonant frequency of the coil antenna is lowered under the influence of the parasitic capacitance. When this self-resonant frequency approaches the frequency used for power feeding, the coil antenna does not function as an antenna.

  If the number of turns of the coil conductor is reduced, the self-resonant frequency will increase, but the magnetic field distribution of the coil antenna will be biased, and the coupling coefficient with the counterpart coil antenna will decrease at low magnetic field locations, reducing power supply efficiency. Will do.

  The above is not limited to power supply, but also occurs in the same manner for coil antennas used for near field communication using the near field.

  An object of the present invention is to provide a coil antenna that is less affected by parasitic capacitance while having a coil antenna having a sparse / dense arrangement of coil conductors, a wireless power feeding system that uses the coil antenna, and a feeding device that constitutes the wireless power feeding system And providing a power receiving device.

(1) The coil antenna of the present invention is
A coil conductor having two connections connected to an external circuit, and having a shape wound a plurality of times around the winding axis along a plane perpendicular to the direction of the winding axis;
The coil conductor has a narrow (dense) gap between adjacent coil conductors and a wider (sparser) gap between adjacent coil conductors than the first coil conductor part. A second coil conductor portion,
The two connection parts are located in the second coil conductor part.

  With the above configuration, the parasitic capacitance generated in the vicinity of the two connecting portions is reduced, so that the self-resonant frequency of the coil antenna is increased. Therefore, communication or power feeding can be performed even in a high frequency band.

(2) In the above (1), it is preferable that the second coil conductor part is closer to the winding axis in the radial direction with the winding axis as the origin than the first coil conductor part. As a result, the bias of the magnetic field distribution can be suppressed, and the coupling coefficient with the coil antenna of the coupling partner can be stabilized within a wide range of the relative positional relationship with the coil antenna of the coupling partner.

(3) In the above (1) or (2), the coil conductor is symmetrical with respect to an axis (symmetric axis) passing between the two connecting portions along a plane orthogonal to the direction of the winding axis. Preferably there is. Thereby, the distribution of the line capacitance between the coil conductors adjacent to each other is symmetric, and the uniformity of the magnetic field radiation is ensured. In addition, when the external circuit connected to the coil antenna is a balanced circuit, the balance seen from the external circuit can be maintained.

(4) The power feeding device of the present invention is
A power feeding device in a wireless power feeding system that feeds power wirelessly from a power feeding device to a power receiving device,
A coil antenna used for coupling with the power receiving device and a power feeding circuit connected to the coil antenna;
The coil antenna has two connection portions connected to the power feeding circuit, and a coil conductor having a shape wound around the winding axis a plurality of times along a plane orthogonal to the direction of the winding axis. Prepared,
The coil conductor has a first coil conductor part in which the interval between the coil conductors adjacent to each other is narrow, and a second coil conductor part in which the interval between the coil conductors adjacent to each other is wider than the first coil conductor part,
The two connection parts are located in the second coil conductor part.

  With the above-described configuration, the self-resonance frequency of the coil antenna can be easily increased, and thus power can be supplied even in a high frequency band.

(5) In the above (4), it is preferable that the power feeding circuit is a circuit for applying an HF band alternating voltage to the coil antenna. As a result, power can be supplied with high efficiency while using a small coil antenna.

(6) The power receiving device of the present invention includes:
A power receiving device in a wireless power feeding system that wirelessly feeds power from a power feeding device to a power receiving device,
A coil antenna used for coupling with the power feeding device and a power receiving circuit connected to the coil antenna;
The coil antenna has two connection portions connected to the power receiving circuit, and a coil conductor having a shape wound around the winding axis a plurality of times along a plane orthogonal to the direction of the winding axis. Prepared,
The coil conductor has a first coil conductor part in which the interval between the coil conductors adjacent to each other is narrow, and a second coil conductor part in which the interval between the coil conductors adjacent to each other is wider than the first coil conductor part,
The two connection parts are located in the second coil conductor part.

  With the above configuration, the self-resonant frequency of the coil antenna can be easily increased, and thus power can be received even in a high frequency band.

(7) In the above (6), the power receiving circuit includes a capacitor, and a resonance circuit is configured by the coil antenna and the capacitor. The resonance circuit has a frequency of an alternating magnetic field (HF band) supplied from the power feeding device. Resonance) at a frequency). As a result, power can be received with high efficiency while using a small coil antenna.

(8) The wireless power feeding system of the present invention includes:
A wireless power feeding system that wirelessly feeds power from a power feeding device to a power receiving device,
The power supply device
A coil antenna used for coupling with the power receiving device and a power feeding circuit connected to the coil antenna;
The coil antenna has two connection portions connected to the power feeding circuit, and a coil conductor having a shape wound around the winding axis a plurality of times along a plane orthogonal to the direction of the winding axis. Prepared,
The coil conductor has a first coil conductor part in which the interval between the coil conductors adjacent to each other is narrow, and a second coil conductor part in which the interval between the coil conductors adjacent to each other is wider than the first coil conductor part,
The two connection parts are located in the second coil conductor part.

  With the above-described configuration, the self-resonant frequency of the coil antenna can be easily increased, so that power can be supplied even in a high frequency band.

(9) In the above (8), it is preferable that the power feeding circuit is a circuit that applies an HF band alternating voltage to the coil antenna. This makes it possible to supply power with high efficiency while using a small coil antenna.

(10) The wireless power feeding system of the present invention includes:
A wireless power feeding system that wirelessly feeds power from a power feeding device to a power receiving device,
The power receiving device is:
A coil antenna used for coupling with the power feeding device and a power receiving circuit connected to the coil antenna;
The coil antenna has two connection portions connected to the power receiving circuit, and a coil conductor having a shape wound around the winding axis a plurality of times along a plane orthogonal to the direction of the winding axis. Prepared,
The coil conductor has a first coil conductor part in which the interval between the coil conductors adjacent to each other is narrow, and a second coil conductor part in which the interval between the coil conductors adjacent to each other is wider than the first coil conductor part,
The two connection parts are located in the second coil conductor part.

  With the above-described configuration, the self-resonant frequency of the coil antenna can be easily increased, so that power can be supplied even in a high frequency band.

(11) In the above (10), the power receiving circuit includes a capacitor, and a resonance circuit is configured by the coil antenna and the capacitor. The resonance circuit has a frequency of an alternating magnetic field (HF band) supplied from the power feeding device. Resonance) at a frequency). This makes it possible to supply power with high efficiency while using a small coil antenna.

  According to the present invention, since the parasitic capacitance generated in the vicinity of the two connecting portions of the coil conductor is reduced, the self-resonant frequency of the coil antenna is increased. Therefore, communication or power feeding can be performed even in a high frequency band.

FIG. 1 is a diagram illustrating a configuration of a coil antenna 11 according to the first embodiment. FIG. 2 is a plan view of a coil antenna 12A according to the second embodiment. FIG. 3 is a plan view of another coil antenna 12B according to the second embodiment. FIG. 4 is a plan view of the coil antenna 13 according to the third embodiment. FIG. 5 is a diagram illustrating configurations of the coil antenna 14 and the power feeding / communication device 104 according to the fourth embodiment. FIG. 6 is a circuit diagram of the power supply / communication device 104 of the fourth embodiment. FIG. 7 is a circuit diagram of a wireless power feeding system 301 according to the fifth embodiment. FIG. 8 is a perspective view illustrating configurations of the power feeding coil antenna Lt and the power receiving coil antenna Lr according to the fifth embodiment. FIG. 9 is a plan view of the coil antenna disclosed in Patent Document 1. FIG.

  Hereinafter, several specific examples will be given with reference to the drawings to show a plurality of modes for carrying out the present invention. In each figure, the same reference numerals are assigned to the same portions. In consideration of ease of explanation or understanding of the main points, the embodiments are shown separately for convenience, but partial replacement or combination of configurations shown in different embodiments is possible. In the second and subsequent embodiments, description of matters common to the first embodiment is omitted, and only different points will be described. In particular, the same operation effect by the same configuration will not be sequentially described for each embodiment.

  The “coil antenna” shown in each embodiment can be applied to either a signal (or power) transmission (power supply) side or a reception (power reception) side. Even when this “coil antenna” is described as an antenna that radiates magnetic flux, the coil antenna is not limited to being a magnetic flux generation source. Even when the magnetic flux generated by the power supply counterpart coil antenna is received (interlinked), that is, even when the transmission / reception relationship is reversed, the same effect is obtained.

  The “coil antenna” shown in the following embodiments is a coil antenna used for near-field communication using magnetic field coupling with a communication partner coil antenna, or a vicinity using magnetic coupling with a power feeding counterpart coil antenna. It is a coil antenna used for power supply in the field. In the case of communication, it is applied to a communication system such as NFC (Near field communication). In the case of power feeding, the present invention is applied to a power feeding system such as an electromagnetic induction method or a magnetic field resonance method.

  As the “coil antenna” shown in each embodiment, for example, an HF band, particularly 13.56 MHz, 6.78 MHz, or a frequency band in the vicinity thereof is used. The size of the coil antenna is sufficiently smaller than the wavelength λ at the used frequency, and the radiation efficiency of the electromagnetic wave is low in the used frequency band. The size of the coil antenna is λ / 10 or less. In addition, the wavelength here is an effective wavelength in consideration of the wavelength shortening effect by the dielectric property and permeability of the base material on which the coil antenna conductor is formed.

<< First Embodiment >>
FIG. 1 is a diagram illustrating a configuration of a coil antenna 11 according to the first embodiment.

  The coil antenna 11 includes a coil conductor 21 formed on the insulating base material 20. The coil conductor 21 has two connection portions T1 and T2 connected to the external circuit 90, and around the winding axis CA along a plane orthogonal to the winding axis CA (surface of the insulating base material 20). The shape is wound several times.

  The winding pattern of the coil conductor 21 of the present embodiment is symmetric with respect to an axis (symmetric axis) SA passing between the two connecting portions T1 and T2 along a plane orthogonal to the winding axis CA. The coil conductor 21 has twisted portions TW1, TW2, and TW3 that are twisted with each other so that the paths of adjacent coil conductors are interchanged. These twisted portions TW1, TW2, and TW3 intersect with each other through an insulating layer so that adjacent coil conductors are not short-circuited. Note that the coil conductor 21 may be formed on both surfaces of the insulating base material 20, and the insulating properties of the twisted portions TW 1, TW 2, and TW 3 may be ensured by the insulating base material 20.

  In the coil conductor 21, the interval between the coil conductors 21 adjacent to each other is narrow (dense), and the interval between the coil conductors 21 adjacent to each other is wider (sparser than the first coil conductor unit CC1). ) The second coil conductor portion CC2. In FIG. 1, a convenient boundary between the first coil conductor part CC1 and the second coil conductor part CC2 is represented by a boundary line BL.

  The second coil conductor portion CC2 is closer to the winding axis CA in the radial direction with the winding axis CA as the origin than the first coil conductor portion CC1. That is, the interval between the coil conductors 21 adjacent to each other is “sparse” near the inner periphery of the winding range and “dense” near the outer periphery. The two connection portions T1 and T2 of the coil conductor 21 exist in the second coil conductor portion CC2 in which the distance between the coil conductors 21 is “sparse”. Further, the two connecting portions T1 and T2 are present at adjacent positions in the same turn (in this example, the innermost turn) of the coil conductor. If the coil conductors 21 are equally spaced, the magnetic flux density around the coil conductor 21 near the winding axis CA is high, and the magnetic flux density around the coil conductor 21 far from the winding axis is low. Become. Thus, by making the interval between the coil conductors 21 closer to the winding axis CA in this way, variation in the magnetic field distribution formed by the coil conductor can be suppressed, and a uniform magnetic field distribution can be formed. .

  When the coil antenna 11 is applied to, for example, a power feeding device in a power feeding system, the external circuit 90 connected to the connecting portions T1 and T2 applies an alternating voltage having a predetermined frequency to the coil conductor 21 (energizes an alternating current). This is a power feeding circuit. Further, when the coil antenna 11 is applied to a near field communication system such as NFC, the external circuit 90 is a communication circuit.

  According to the present embodiment, the two connection portions T1 and T2 are arranged in the second coil conductor portion CC2 having a large coil conductor interval. The parasitic capacitance generated in the coil antenna 11 is determined by the interval between adjacent coil conductors and the potential difference between the coil conductors. The coil conductor 21 has a high potential difference between the connecting portions T1 and T2, and is easily affected by parasitic capacitance. By arranging the connection portions T1 and T2 in the second coil conductor portion CC2 having a large coil conductor interval, it is possible to suppress the influence of parasitic capacitance generated between the coil conductors in the vicinity of the two connection portions T1 and T2. Therefore, the self-resonant frequency of the coil antenna 11 is higher than when the two connecting portions exist in the first coil conductor portion CC1 having a narrow coil conductor interval. Further, in the first coil conductor portion where the coil conductor interval is narrow, the potential difference between adjacent coil conductors is low, so that it is difficult to be affected by parasitic capacitance generated between the coil conductors. By suppressing the influence of the parasitic capacitance of the coil antenna 11, the self-resonant frequency of the coil antenna 11 can be increased. Therefore, the coil antenna 11 of the present embodiment can perform communication or power feeding even in a frequency band with a high operating frequency.

  Further, since the coil conductor 21 is symmetric with respect to an axis (symmetric axis) SA passing between the two connection portions T1 and T2 along a plane orthogonal to the winding axis CA, the coil conductors 21 are adjacent to each other. The distribution of the line capacitance is symmetric, and the uniformity of the magnetic field radiation can be ensured. Further, when the external circuit 90 connected to the coil antenna 11 is a balanced circuit, it is possible to maintain balance as viewed from the external circuit.

  Note that the shape of the coil antenna 11 does not have to be square. For example, the shape may be a circle, an ellipse, or a combination of a straight line and a curve. Further, the number of turns may be 4 turns or more.

<< Second Embodiment >>
In 2nd Embodiment, the example of a coil antenna provided with the coil conductor in which the winding pattern of a coil conductor is asymmetrical is shown.

  FIG. 2 is a plan view of a coil antenna 12A according to the second embodiment. FIG. 3 is a plan view of another coil antenna 12B according to the second embodiment.

  Each of the coil antenna 12 </ b> A of FIG. 2 and the coil antenna 12 </ b> B of FIG. 3 includes a coil conductor 21 formed on the insulating substrate 20. The coil conductor 21 has two connection portions T1 and T2 connected to the external circuit 90, and around the winding axis CA along a plane orthogonal to the winding axis CA (surface of the insulating base material 20). It has a winding pattern that is wound a plurality of times. The winding pattern is asymmetric with respect to an axis (symmetric axis) passing through the winding axis CA. Further, the coil conductor 21 does not have a twisted portion (twisted portions TW1, TW2, TW3 in the first embodiment) that are twisted with each other so that the paths of adjacent coil conductors are interchanged.

  The coil conductor 21 of the coil antenna 12A in FIG. 2 has a rectangular spiral shape, and the coil conductor 21 of the coil antenna 12B in FIG. 3 has a circular spiral shape.

  In both the coil antenna 12A and the coil antenna 12B, the coil conductor 21 includes a first coil conductor portion CC1 in which the interval between the adjacent coil conductors 21 is narrow, and an interval between the adjacent coil conductors 21 in the first coil conductor portion CC1. A wider second coil conductor portion CC2. In FIG. 2 and FIG. 3, a convenient boundary between the first coil conductor portion CC1 and the second coil conductor portion CC2 is indicated by a boundary line BL. Two connection portions T1 and T2 of the coil conductor 21 exist in the second coil conductor portion CC2.

  Similarly to the first embodiment, also in this embodiment, the two connection portions T1 and T2 are present in the second coil conductor portion CC2 having a wide coil conductor interval, and therefore the coil conductors near the two connection portions T1 and T2 are used. The parasitic capacitance generated between them is small. Further, the coil conductor 21 is wound in a rectangular spiral shape so that the potential difference between the adjacent coil conductors 21 is lower than that in the first embodiment. Therefore, the self-resonant frequency of the coil antenna 11 is higher than when the two connecting portions exist in the first coil conductor portion CC1 having a narrow coil conductor interval. Therefore, the coil antenna 11 of the present embodiment can perform communication or power feeding even in a frequency band with a high operating frequency.

<< Third Embodiment >>
In the third embodiment, an example of a coil antenna in which the positional relationship between the first coil conductor portion and the second coil conductor portion is different from those in the first and second embodiments is shown.

  FIG. 4 is a plan view of the coil antenna 13 according to the third embodiment. The coil antenna 13 includes a coil conductor 21 formed on the insulating base material 20. The coil conductor 21 has two connection portions T1 and T2 connected to the external circuit 90, and around the winding axis CA along a plane orthogonal to the winding axis CA (surface of the insulating base material 20). It has a winding pattern that is wound a plurality of times.

  The coil conductor 21 of the coil antenna 13 includes a first coil conductor portion CC1 in which the interval between adjacent coil conductors 21 is narrow, and a second coil conductor portion in which the interval between adjacent coil conductors 21 is wider than the first coil conductor portion CC1. CC2. In FIG. 4, a convenient boundary between the first coil conductor portion CC1 and the second coil conductor portion CC2 is indicated by a boundary line BL. Two connection portions T1 and T2 of the coil conductor 21 exist in the second coil conductor portion CC2.

  Unlike the coil antennas shown in the first and second embodiments, the second coil conductor portion CC2 is farther from the winding axis CA in the radial direction with the winding axis CA as the origin than the first coil conductor portion CC1. That is, the interval between the adjacent coil conductors 21 is “dense” near the inner periphery of the winding range and “sparse” near the outer periphery.

  Also in this embodiment, the parasitic capacitance generated between the coil conductors in the vicinity of the two connection portions T1 and T2 is small. Therefore, the self-resonant frequency of the coil antenna 11 is higher than when the two connecting portions exist in the first coil conductor portion CC1 having a narrow coil conductor interval. Therefore, the coil antenna 11 of the present embodiment can perform communication or power feeding even in a frequency band with a high operating frequency.

<< Fourth Embodiment >>
In the fourth embodiment, a coil antenna and a power feeding / communication device including two intermediate connection portions in addition to the two connection portions will be described.

  FIG. 5 is a diagram illustrating configurations of the coil antenna 14 and the power feeding / communication device 104 according to the fourth embodiment.

  The coil antenna 14 includes a coil conductor 21 formed on the insulating base material 20. The coil conductor 21 has a shape wound around the winding axis a plurality of times along a plane orthogonal to the winding axis (surface of the insulating base material 20).

  The coil conductor 21 has two connection portions T11 and T12, and the power feeding circuit 111 is connected to the connection portions T11 and T12. Further, the coil conductor 21 has intermediate connection portions T21 and T22 on the way, and the communication circuit 411 is connected to the intermediate connection portions T21 and T22. The configuration of the coil antenna 14 is the same as that of the coil antenna 11 shown in the first embodiment except that the intermediate connection portions T21 and T22 are provided.

  FIG. 6 is a circuit diagram of the power feeding / communication device of the present embodiment. In FIG. 6, a coil L211 is connected between the intermediate connection portions T21 and T22 and corresponds to a coil conductor near the outer periphery of the coil winding pattern. The coil L212 is connected between the connection portion T12 and the intermediate connection portion T21 and corresponds to a coil conductor closer to the inner periphery of the coil winding pattern, and the coil L213 is connected between the connection portion T11 and the intermediate connection portion T22. And corresponds to a coil conductor closer to the inner periphery of the coil winding pattern.

  When the coil antenna 14 is used as a coil antenna for supplying wireless power, the switch SW1 is turned on and the switch SW2 is turned off. When the coil antenna 14 is used as a communication coil antenna, the switch SW2 is turned on and the switch SW1 is turned off.

  The power feeding circuit 111 is a power feeding circuit for wireless power supply, and applies an alternating voltage in the HF band to the entire coil conductor 21 of the coil antenna 14 in a state where the communication circuit 411 is not connected (AC voltage). Energize). In addition, the communication circuit 411 transmits or receives a communication signal by using a part of the coil conductor 21 as a coil antenna in a state where the power feeding circuit 111 is not connected. The coil antenna 14 forms a resonance circuit with a resonance capacitor provided in the power supply circuit 111, and resonates at a frequency for wireless power supply (for example, 6.78 MHz). The coil antenna 14 forms a resonance circuit with a resonance capacitor provided in the communication circuit 411, and resonates at a communication frequency (for example, 13.56 MHz).

  According to this embodiment, a single coil antenna can be shared by different systems, such as power supply and communication. Moreover, it can be used as a coil antenna of different frequency bands.

<< Fifth Embodiment >>
In the fifth embodiment, an example of a wireless power supply system is shown.

  FIG. 7 is a circuit diagram of a wireless power feeding system 301 according to the fifth embodiment. The wireless power supply system 301 includes a power supply apparatus 101 and a power reception apparatus 201.

  The power feeding apparatus 101 includes a power feeding coil antenna Lt and a resonance capacitor Ct connected in series to the coil antenna Lt. The coil antenna Lt and the resonance capacitor Ct constitute a resonance circuit. The power feeding apparatus 101 includes a power feeding circuit 111 that converts the DC input voltage Vi to an AC voltage and applies the AC voltage to the resonance circuit. The power feeding circuit 111 includes switching elements Q1 and Q2, a capacitor C11, a diode D1, and a driving circuit 112. The drive circuit 112 alternately drives the switching elements Q1 and Q2 on / off at the HF band operating frequency (eg, 6.78 MHz). The resonance frequency of the resonance circuit is the operating frequency or a frequency in the vicinity thereof.

  The resonance circuit may have a configuration in which the resonance capacitor Ct is connected in series to both ends of the power feeding coil antenna Lt, or may be a parallel resonance circuit in which the resonance capacitor Ct and the power feeding coil antenna Lt are connected in parallel.

  The power receiving apparatus 201 includes a power receiving coil antenna Lr and a resonance capacitor Cr connected in parallel to the coil antenna Lr. The coil antenna Lr and the resonance capacitor Cr constitute a resonance circuit. The power receiving coil antenna Lr and the power feeding coil antenna Lt are mainly magnetically coupled. The power receiving apparatus 201 includes a power receiving circuit 211 that converts an AC voltage generated in the resonance circuit of the power receiving apparatus 201 into a DC voltage, and a load Ro that is driven by the DC output voltage converted by the power receiving circuit 211. The power receiving circuit 211 includes a rectifier circuit 212 based on a diode bridge circuit, smoothing capacitors C21 and C22, and a voltage regulator circuit 213. The resonance circuit may be configured by connecting a resonance capacitor Cr in series to the coil antenna Lr to form a series resonance circuit.

  The resonance circuit of the power receiving device 201 resonates at the frequency of the alternating magnetic field in the HF band or a frequency in the vicinity thereof. The resonant voltage of this resonant circuit is full-wave rectified by the rectifier circuit 212, smoothed and stabilized by the smoothing capacitors C21 and C22, and the voltage regulator circuit 213, and a predetermined constant voltage Vo is supplied to the load Ro.

  FIG. 8 is a perspective view showing configurations of the power feeding coil antenna Lt and the power receiving coil antenna Lr. In the example shown in FIG. 8, the power feeding coil antenna Lt is the coil antenna (coil antenna 11) having the structure shown in the first embodiment, and the power receiving coil antenna Lr includes a normal rectangular spiral coil conductor. It is a coil antenna. The power feeding coil antenna Lt and the power feeding circuit 111 constitute a power feeding device 105, and the power receiving coil antenna Lr and the power receiving circuit 211 constitute a power receiving device 205.

  In the power feeding coil antenna Lt of the present embodiment, in the radial direction from the winding axis, a portion where the distance between the coil conductors is dense is located closer to the outer periphery, and a sparse portion is located closer to the inner periphery. . In general, a coil antenna wound so that the intervals between coil conductors are equal to each other is such that a current flows through the coil antenna on the upper surface (or lower surface) of the coil antenna in the winding axis direction of the coil antenna. The component of the resulting magnetic flux density in the winding axis direction is stronger as it is closer to the winding axis (coil center) in the radial direction, and weaker as it is farther from the winding axis (coil center). In the coil antenna Lt of the present embodiment, the coil conductor is wound so that the distance between the coil conductors becomes closer to the outer periphery from the winding axis in the radial direction, and therefore the magnetic flux density on the upper surface (or lower surface) of the coil antenna. The winding axis direction component of becomes uniform. As a result, the tendency of the degree of coupling to decrease due to a shift in the relative positional relationship is suppressed, and the coupling coefficient with the coupling partner coil antenna is stabilized in a wide range of the relative positional relationship with the coupling partner coil antenna.

  In each of the embodiments described above, the coil conductor 21 has been described as being divided into the first coil conductor portion CC1 and the second coil conductor portion CC2 for convenience. However, the interval between the coil conductors 21 adjacent to each other is determined as follows. It may change gradually according to the distance from the rotation axis, or may change stepwise.

  Moreover, in each embodiment shown above, although the example in which the coil conductor was formed in the planar insulating base material was shown, the insulating base material in which the coil conductor is formed may be curved. , Some may be planar or some may be curved.

  Moreover, you may form a coil conductor in the insulating base material which has a multilayer structure. Furthermore, the coil conductor does not need to be formed on the insulating base material, and the coil antenna may be constituted by a copper wire or the like.

  Finally, the description of the above embodiment is illustrative in all respects and not restrictive. Those skilled in the art can make modifications and changes as appropriate. The scope of the present invention is shown not by the above embodiments but by the claims. Furthermore, the scope of the present invention includes modifications from the embodiments within the scope equivalent to the claims.

BL ... Boundary C11 ... Capacitors C21, C22 ... Smoothing capacitor CA ... Wound axis CC1 ... First coil conductor CC2 ... Second coil conductor Cr, Ct ... Resonance capacitor D1 ... Diodes L211, L212, L213 ... Coil Lr ... Power receiving coil antenna Lt ... Power feeding coil antennas Q1, Q2 ... Switching element Ro ... Loads SW1, SW2 ... Switches T1, T2 ... Connection portions T11, T12 ... Connection portions T21, T22 ... Intermediate connection portions TW1, TW2, TW3 ... Twist Parts 11, 12A, 12B, 13, 14 ... Coil antenna 20 ... Insulating substrate 21 ... Coil conductor 30 ... Coil conductor 90 ... External circuit 101, 105 ... Power feeding device 104 ... Power feeding / communication device 111 ... Power feeding circuit 112 ... Drive Circuits 201, 205 ... Power receiving device 211 ... Power receiving circuit 212 ... Rectifier circuit 213 ... Voltage level Regulator circuit 301 ... wireless power feeding system 411 ... communication circuit

Claims (11)

A coil conductor having two connections connected to an external circuit, and having a shape wound a plurality of times around the winding axis along a plane perpendicular to the direction of the winding axis;
The coil conductor has a first coil conductor part in which the interval between the coil conductors adjacent to each other is narrow, and a second coil conductor part in which the interval between the coil conductors adjacent to each other is wider than the first coil conductor part,
The coil antenna according to claim 1, wherein the two connection portions are located in the second coil conductor portion.   2. The coil antenna according to claim 1, wherein the second coil conductor portion is closer to the winding axis in a radial direction with the winding axis as an origin than the first coil conductor portion.   The coil antenna according to claim 1 or 2, wherein the coil conductor is symmetric with respect to an axis passing between the two connecting portions along a plane orthogonal to the direction of the winding axis. A power feeding device in a wireless power feeding system that feeds power wirelessly from a power feeding device to a power receiving device,
A coil antenna used for coupling with the power receiving device and a power feeding circuit connected to the coil antenna;
The coil antenna has two connection portions connected to the power feeding circuit, and a coil conductor having a shape wound around the winding axis a plurality of times along a plane orthogonal to the direction of the winding axis. Prepared,
The coil conductor has a first coil conductor part in which the interval between the coil conductors adjacent to each other is narrow, and a second coil conductor part in which the interval between the coil conductors adjacent to each other is wider than the first coil conductor part,
The power supply apparatus, wherein the two connection portions are located in the second coil conductor portion.   The power feeding device according to claim 4, wherein the power feeding circuit applies an HF band alternating voltage to the coil antenna. A power receiving device in a wireless power feeding system that wirelessly feeds power from a power feeding device to a power receiving device,
A coil antenna used for coupling with the power feeding device and a power receiving circuit connected to the coil antenna;
The coil antenna has two connection portions connected to the power receiving circuit, and a coil conductor having a shape wound around the winding axis a plurality of times along a plane orthogonal to the direction of the winding axis. Prepared,
The coil conductor has a first coil conductor part in which the interval between the coil conductors adjacent to each other is narrow, and a second coil conductor part in which the interval between the coil conductors adjacent to each other is wider than the first coil conductor part,
The power receiving device, wherein the two connection portions are located in the second coil conductor portion. The power receiving circuit includes a capacitor, and a resonance circuit is configured by the coil antenna and the capacitor,
The power receiving device according to claim 6, wherein the resonance circuit resonates at a frequency of an alternating magnetic field supplied from the power feeding device. A wireless power feeding system that wirelessly feeds power from a power feeding device to a power receiving device,
The power supply device
A coil antenna used for coupling with the power receiving device and a power feeding circuit connected to the coil antenna;
The coil antenna has two connection portions connected to the power feeding circuit, and a coil conductor having a shape wound around the winding axis a plurality of times along a plane orthogonal to the direction of the winding axis. Prepared,
The coil conductor has a first coil conductor part in which the interval between the coil conductors adjacent to each other is narrow, and a second coil conductor part in which the interval between the coil conductors adjacent to each other is wider than the first coil conductor part,
The two connection parts are located in the second coil conductor part,
Wireless power supply system.   The wireless power feeding system according to claim 8, wherein the feeding circuit applies an HF band alternating voltage to the coil antenna. A wireless power feeding system that wirelessly feeds power from a power feeding device to a power receiving device,
The power receiving device is:
A coil antenna used for coupling with the power feeding device and a power receiving circuit connected to the coil antenna;
The coil antenna has two connection portions connected to the power receiving circuit, and a coil conductor having a shape wound around the winding axis a plurality of times along a plane orthogonal to the direction of the winding axis. Prepared,
The coil conductor has a first coil conductor part in which the interval between the coil conductors adjacent to each other is narrow, and a second coil conductor part in which the interval between the coil conductors adjacent to each other is wider than the first coil conductor part,
The two connection parts are located in the second coil conductor part,
Wireless power supply system. The power receiving circuit includes a capacitor, and a resonance circuit is configured by the coil antenna and the capacitor,
The wireless power supply system according to claim 10, wherein the resonance circuit resonates at a frequency of an alternating magnetic field supplied from the power supply apparatus.

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