JPWO2017169709A1 - Coil antenna, power feeding device, power receiving device, and wireless power supply system - Google Patents

Abstract

The coil antenna (101) includes a coil conductor (31) wound around a winding axis (AX) and a first conductive member (11A, 11B, 11C, 11D). The first conductive member (11A, 11B, 11C, 11D) is a minimum portion of the radius of curvature at least partially in the circumferential direction of the coil conductor (31) when viewed from the winding axis (AX) direction (Z-axis direction). Overlapping (PS). The first conductive member (11A, 11B, 11C, 11D) has a cutout portion (C1, C2, C3, C4). These cut-out portions (C1, C2, C3, C4) do not overlap with the coil conductor (31) other than the minimal portion (PS) when viewed from the Z-axis direction.

Description

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

  2. Description of the Related Art Conventionally, there is known a magnetic resonance power supply system that enables wireless power supply by magnetically coupling a power feeding coil antenna and a power receiving coil antenna (Patent Document 1).

  For example, Patent Document 1 discloses a planar spiral power supply coil having a structure in which a coil conductor is sparsely wound on an inner peripheral portion having a high magnetic flux density, and a coil conductor is densely wound on an outer peripheral portion having a low magnetic flux density. An antenna is disclosed. With the above structure, the magnetic flux generated on the feeding coil antenna is constant, and the variation in coupling strength due to the relative positional relationship with the coil antenna of the coupling partner is suppressed, and the relative positional relationship with the coil antenna of the coupling partner The change in power supply efficiency due to is reduced.

Japanese Patent No. 5221111

  However, if only the above structure is adopted for the coil antenna, a parasitic capacitance between the coil conductors is generated at the portion where the coil conductors are densely wound. It is difficult to configure a coil antenna that suppresses variations in coupling strength due to relationships.

  An object of the present invention is to provide a coil antenna having a small change in coupling strength due to a relative positional relationship with a coil antenna of a coupling partner by a simple structure. It is another object of the present invention to provide a power feeding device, a power receiving device, and a wireless power supply system including the same.

(1) The coil antenna of the present invention is used in a wireless power supply system,
A coil conductor wound a plurality of times around a winding axis;
A first conductive member that is at least partially overlapped with a minimal portion of a radius of curvature in the circumferential direction of the coil conductor, as viewed from the winding axis direction;
With
The said 1st electroconductive member is a coil antenna which has the extraction part which does not overlap with the said coil conductors other than the said minimum part seeing from the said winding axis direction.

  In general, the magnetic flux tends to concentrate inside the minimal portion of the radius of curvature in the circumferential direction of the coil conductor, and the magnetic flux density tends to be relatively higher than other portions of the coil conductor. On the other hand, in this configuration, when viewed from the winding axis direction, at least a part of the first conductive member overlaps with a minimum portion of the coil conductor that tends to have a relatively high magnetic flux density, and the magnetic flux density is relatively high. The first conductive member does not overlap except for the minimum portion of the coil conductor that tends to be low. Therefore, the magnetic field formation at the minimum portion is partially hindered by the first conductive member, and variation in coupling strength due to the relative positional relationship with the coil antenna of the coupling partner is suppressed. Therefore, it is possible to realize a coil antenna having a stable coupling coefficient with the coil antenna of the coupling partner in a wide range of relative positional relationships by a simple structure.

(2) In the above (1), it is preferable that the first conductive member overlaps a plurality of the minimum portions and extends in the radial direction of the coil conductor when viewed from the winding axis direction. In this configuration, a single first conductive member is overlapped with a plurality of minimum portions of the coil conductor as viewed from the winding axis direction. Therefore, it is only necessary to provide a small number of first conductive members with a simple shape.

(3) In the above (1) or (2), the coil conductor is axisymmetric with respect to an axis passing through the two end portions and intersecting the winding axis as viewed from the winding axis direction. It is preferable. With this configuration, the distribution of the line capacitance between adjacent coil conductors is symmetric, and the uniformity of 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) In any one of the above (1) to (3), the coil conductor includes an outer peripheral coil conductor portion wound in a first direction as viewed from the winding axis direction, and the first direction. An inner circumference coil conductor portion wound in a reverse direction, and the outer circumference coil conductor portion is viewed from the direction of the winding axis, and the distance from the winding axis in the radial direction is the inner circumference coil. It is preferable that the number of turns of the outer peripheral coil conductor part is greater than the number of turns of the inner peripheral coil conductor part. In this configuration, a magnetic flux is generated around the inner peripheral coil conductor portion of the coil conductor, and a part of the magnetic flux (magnetic flux generated from the outer peripheral coil conductor portion) that contributes to magnetic field coupling with the coil antenna of the coupling partner is canceled out. Therefore, with this configuration, variation in coupling strength due to a relative positional relationship with the coil antenna of the coupling partner is suppressed.

(5) In any one of the above (1) to (4), the coil conductor includes a first coil conductor portion that is close in distance from the winding axis in the radial direction, and the coil conductor from the winding axis in the radial direction. A distance between the adjacent coil conductors is greater in the first coil conductor part than in the second coil conductor part. Is preferred. In this configuration, when viewed from the winding axis direction, the outer periphery (second coil conductor portion) of the coil conductor, where the magnetic flux density tends to be low, is densely wound, and the inner periphery (first) of the coil conductor, where the magnetic flux density tends to be high. The coil conductor portion is loosely wound. 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). According to the above configuration, since the coil conductors are wound so that the distance between the coil conductors becomes closer to the outer periphery from the winding axis in the radial direction, the magnetic flux density is increased on the upper surface (or lower surface) of the coil antenna. The winding axis direction component is uniform. Therefore, a variation in the coupling strength due to the relative positional relationship with the coil antenna of the coupling partner is suppressed, and the coupling antenna with which the coupling coefficient with the coil antenna of the coupling partner is stabilized in a wide range of relative positional relationships. realizable.

(6) In said (5), it is preferable that the line width of the said 1st coil conductor part is thicker than the line width of the said 2nd coil conductor part. With this configuration, the DC resistance component of the entire coil antenna can be reduced. In addition, the inductance value of the coil antenna is lower when the line width of the coil conductor is thicker than when the line width of the coil conductor constituting the coil antenna is narrow. Therefore, with this configuration, the inductance value of the entire coil antenna is lower than when the line width of the entire coil conductor is the same. Therefore, if the coil antenna has the same inductance value, the number of turns of the coil conductor can be further increased by the above configuration.

(7) In any one of the above (1) to (6), the coil conductor further includes a second conductive member that overlaps the coil conductor as viewed from the winding axis direction, and the coil conductor has the winding in the radial direction. A first coil conductor portion having a short distance from the shaft; and a second coil conductor portion having a distance from the winding shaft in the radial direction that is farther than the first coil conductor portion. Preferably, the member overlaps the first coil conductor portion and does not overlap the second coil conductor portion when viewed from the winding axis direction. In this configuration, when viewed from the winding axis direction, the second conductive member overlaps with the inner circumference (first coil conductor portion) of the coil conductor where the magnetic flux density tends to be high, and the outer circumference of the coil conductor where the magnetic flux density tends to be low ( The second conductive member does not overlap the second coil conductor portion. Therefore, the magnetic field formation in the first coil conductor portion is partly hindered by the second conductive member, and variations in magnetic flux density formed by the coil conductor are suppressed. Since the magnetic flux density formed by the coil conductor is uniform, variation in coupling strength due to the relative positional relationship with the coil antenna of the coupling partner is suppressed.

(8) In any one of the above (1) to (7), the first conductive member is preferably a mesh conductor. With this configuration, deterioration of antenna characteristics due to parasitic capacitance generated between the first conductive member and the coil conductor is suppressed.

(9) In the above (7) or (8), the second conductive member is preferably a mesh conductor. With this configuration, deterioration of antenna characteristics due to parasitic capacitance generated between the second conductive member and the coil conductor is suppressed.

(10) In any one of the above (1) to (9), the coil conductor may have a rectangular spiral shape having four minimum portions of a radius of curvature in one turn.

(11) The power feeding device of the present invention
A power feeding device in a wireless power supply system that wirelessly supplies power from a power feeding device to a power receiving device,
A coil antenna for feeding used for coupling with the power receiving device;
A feeding circuit connected to the feeding coil antenna;
With
The feeding coil antenna is
A coil conductor wound a plurality of times around a winding axis;
A first conductive member that is at least partially overlapped with a minimal portion of a radius of curvature in the circumferential direction of the coil conductor, as viewed from the winding axis direction;
With
The first conductive member has a cut-out portion that does not overlap the coil conductor other than the minimal portion when viewed from the winding axis direction.

  With this configuration, it is possible to realize a power feeding device including a power feeding coil antenna with little change in coupling strength due to a relative positional relationship with the coupling partner coil antenna.

(12) In the above (11), the power feeding circuit may apply an HF band alternating voltage to the power feeding coil antenna.

(13) The power receiving device of the present invention includes:
A power receiving device in a wireless power supply system that wirelessly supplies power from a power feeding device to a power receiving device,
A power receiving coil antenna used for coupling with the power feeding device;
A power receiving circuit connected to the power receiving coil antenna;
With
The power receiving coil antenna is:
A coil conductor wound a plurality of times around a winding axis;
A first conductive member that is at least partially overlapped with a minimal portion of a radius of curvature in the circumferential direction of the coil conductor, as viewed from the winding axis direction;
With
The first conductive member has a cut-out portion that does not overlap the coil conductor other than the minimal portion when viewed from the winding axis direction.

  With this configuration, it is possible to realize a power feeding device including a power receiving coil antenna in which a change in coupling strength due to a relative positional relationship with the coupling partner coil antenna is small.

(14) In the above (13), a resonance circuit may be configured by a capacitance component of the power reception circuit and an inductance component of the power reception coil antenna, and the resonance frequency of the resonance circuit may be a frequency in the HF band. .

(15) A wireless power supply system including the power feeding device and the power receiving device of the present invention is:
The power supply device
A power feeding coil antenna used for coupling with a power receiving coil antenna included in the power receiving device;
A feeding circuit connected to the feeding coil antenna;
Have
The feeding coil antenna is
A coil conductor wound a plurality of times around a winding axis;
A first conductive member that is at least partially overlapped with a minimal portion of a radius of curvature in the circumferential direction of the coil conductor, as viewed from the winding axis direction;
With
The first conductive member has a cut-out portion that does not overlap the coil conductor other than the minimal portion when viewed from the winding axis direction;
An area of the feeding coil antenna forming region is larger than an area of the receiving coil antenna forming region.

  With this configuration, it is possible to realize a wireless power supply system having a power feeding device including a power feeding coil antenna with a small change in coupling strength due to a relative positional relationship with the coupling partner coil antenna.

(16) In the above (15), it is preferable that the first conductive member is disposed on the opposite side to the coil antenna for power reception with respect to the coil conductor. With this configuration, it is possible to suppress the magnetic flux passing through the opening of the coil conductor included in the power feeding coil antenna from being blocked by the first conductive member.

(17) In the above (15) or (16), the power feeding circuit may apply an HF band alternating voltage to the power feeding coil antenna.

(18) A wireless power supply system including the power supply device and the power reception device of the present invention is:
The power receiving device is:
A power receiving coil antenna used for coupling with a power feeding coil antenna included in the power feeding device;
A power receiving circuit connected to the power receiving coil antenna;
Have
The power receiving coil antenna is:
A coil conductor wound a plurality of times around a winding axis;
A first conductive member that is at least partially overlapped with a minimal portion of a radius of curvature in the circumferential direction of the coil conductor, as viewed from the winding axis direction;
With
The first conductive member has a cut-out portion that does not overlap the coil conductor other than the minimal portion when viewed from the winding axis direction;
An area of the feeding coil antenna forming region is larger than an area of the receiving coil antenna forming region.

  With this configuration, it is possible to realize a wireless power supply system including a power receiving device including a power receiving coil antenna with a small change in coupling strength due to a relative positional relationship with the coupling partner coil antenna.

(19) In the above (18), it is preferable that the first conductive member is disposed on the opposite side to the coil antenna for feeding with respect to the coil conductor. With this configuration, it is possible to suppress the magnetic flux passing through the opening of the coil conductor included in the power receiving coil antenna from being blocked by the first conductive member.

(20) In the above (18) or (19), a resonance circuit is configured by the capacitance component of the power reception circuit and the inductance component of the power reception coil antenna, and the resonance frequency of the resonance circuit is a frequency in the HF band. There may be.

  According to the present invention, it is possible to realize a coil antenna with a small change in coupling strength due to a relative positional relationship with a coil antenna of a coupling partner with a simple structure. In addition, a power feeding device, a power receiving device, and a wireless power supply system including the same can be realized.

FIG. 1A is a plan view of the coil antenna 101 according to the first embodiment, and FIG. 1B is a plan view of the coil antenna 101 showing a minimum portion PS of the radius of curvature in the circumferential direction of the coil conductor 31. is there. FIG. 2 is a plan view of the coil conductor 31. FIG. 3 is a cross-sectional view showing a coupling relationship between the coil antenna 101 and the coil antenna 201 of the coupling partner. FIG. 4 is a cross-sectional view of a power feeding device 301 including the coil antenna 101 according to the first embodiment. FIG. 5A is a plan view of the coil antenna 102 according to the second embodiment, and FIG. 5B is a plan view of the coil antenna 102 showing a minimum portion PS of the radius of curvature in the circumferential direction of the coil conductor 32. is there. FIG. 6 is a plan view of the coil antenna 103 according to the third embodiment. FIG. 7A is a plan view of the coil conductor 33 showing the inner peripheral coil conductor part MP and the outer peripheral coil conductor part FP, and FIG. 7B shows the first coil conductor part CP1 and the second coil conductor part CP2. It is a top view of the coil conductor 33 which shows. FIG. 8A is a plan view of the coil antenna 104 according to the fourth embodiment, and FIG. 8B is a plan view of the coil conductor 31 showing the inner peripheral coil conductor portion MP and the outer peripheral coil conductor portion FP. is there. FIG. 9 is a cross-sectional view showing a coupling relationship between the coil antenna 104 and the coil antenna 201 of the coupling partner. FIG. 10A is a plan view of the coil antenna 105 according to the fifth embodiment, and FIG. 10B is a plan view of the coil conductor 31 showing the inner peripheral coil conductor portion MP and the outer peripheral coil conductor portion FP. is there. FIG. 11 is a cross-sectional view showing a coupling relationship between the coil antenna 105 and the coupling partner coil antenna 201. FIG. 12 is a plan view of a coil antenna 106 according to the sixth embodiment. FIG. 13A is a plan view of the coil conductor 36 showing the inner peripheral coil conductor part MP and the outer peripheral coil conductor part FP, and FIG. 13B shows the first coil conductor part CP1 and the second coil conductor part CP2. It is a top view of the coil conductor 36 which shows. FIG. 14 is a plan view of a coil antenna 107 according to the seventh embodiment. FIG. 15A is a plan view of the coil conductor 37 showing the inner peripheral coil conductor part MP and the outer peripheral coil conductor part FP, and FIG. 15B shows the first coil conductor part CP1 and the second coil conductor part CP2. It is a top view of the coil conductor 37 which shows. FIG. 16A is a plan view of the coil antenna 108 according to the eighth embodiment, and FIG. 16B is a plan view of the coil antenna 108 showing the minimum portion PS of the radius of curvature in the circumferential direction of the coil conductor 31. is there. FIG. 17 is a circuit diagram of a wireless power supply system 501 according to the ninth embodiment.

  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 the components shown in different embodiments can be partially replaced or combined. 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 present invention is suitable for a system that requires a degree of positional freedom on a plane, such as a mouse and a mouse pad. In each of the embodiments described below, when wireless power is supplied to a mouse, the “coil antenna” in the present invention is provided on a mouse pad, for example, and the power receiving side coil antenna is provided on the mouse.

<< First Embodiment >>
FIG. 1A is a plan view of the coil antenna 101 according to the first embodiment, and FIG. 1B is a plan view of the coil antenna 101 showing a minimum portion PS of the radius of curvature in the circumferential direction of the coil conductor 31. is there. FIG. 2 is a plan view of the coil conductor 31. In FIG. 1A, in order to make the structure easy to understand, the substrate 1 is not shown, and texture patterns are given to the first conductive members 11A, 11B, 11C, and 11D. Further, in FIG. 1B, the first conductive members 11A, 11B, 11C, and 11D are not shown for easy understanding of the structure.

  The coil antenna 101 includes a base material 1, a coil conductor 31, and a plurality of first conductive members 11A, 11B, 11C, and 11D.

  The substrate 1 is a rectangular flat plate made of an insulating material. The coil conductor 31 is a rectangular spiral conductor pattern of about 4 turns formed on the surface of the base material 1 and wound around the winding axis AX, and includes a first end E1 and a second end E2. Have. The base material 1 is a resin sheet such as polyimide (PI) or liquid crystal polymer (LCP), and the coil conductor 31 is a Cu foil pattern, for example.

  The plurality of first conductive members 11A, 11B, 11C, and 11D are rectangular flat plates. Some of the plurality of first conductive members 11A, 11B, 11C, and 11D overlap the coil conductor 31 when viewed from the Z-axis direction (corresponding to the “winding axis direction” in the present invention). The first conductive members 11 </ b> A, 11 </ b> B, 11 </ b> C, and 11 </ b> D overlap with the minimum portion PS of the radius of curvature in the circumferential direction of the coil conductor 31 as viewed from the Z-axis direction. Further, the first conductive members 11A, 11B, 11C, and 11D have extraction portions C1, C2, C3, and C4 that do not overlap the coil conductors 31 other than the minimal portion PS as viewed from the Z-axis direction. The first conductive members 11A, 11B, 11C, and 11D are flat plates made of, for example, metal or graphite.

  In the present embodiment, the coil conductor 31 has four minimum portions PS having a radius of curvature in one turn. In the present embodiment, the first conductive members 11 </ b> A, 11 </ b> B, 11 </ b> C, and 11 </ b> D overlap with the plurality of minimum portions PS and extend in the radial direction of the coil conductor 31 as viewed from the Z-axis direction. is there.

  Here, the “circumferential direction” of the coil conductor in the present invention refers to, for example, a direction extending around the winding axis AX of the coil conductor (see CD in FIG. 2), and the “radial direction” of the coil conductor in the present invention. "" Refers to, for example, a direction (see RD in FIG. 2) orthogonal to the direction in which the coil conductor extends. In other words, the direction along the coil opening CM surrounded by the coil conductor is the “circumferential direction” of the coil conductor, and the direction orthogonal to the circumferential direction is the “radial direction” of the coil conductor.

  Further, the “minimum portion of the radius of curvature in the circumferential direction of the coil conductor” in the present invention is a portion provided in the middle of the coil conductor wound around the winding axis AX as viewed from the Z-axis direction. That is, as in the lead portion XP shown in FIG. 1B, the portion where the radius of curvature is minimized when the coil conductor is pulled out from the inner periphery to the outer periphery, the “radius of curvature in the circumferential direction of the coil conductor” Is excluded from the "minimum part of". The same applies to the following embodiments. The “minimum portion of the radius of curvature in the circumferential direction of the coil conductor” in the present invention is a minimal portion in which the differential coefficient is simply zero when the radius of curvature of the coil conductor viewed from the Z-axis direction is differentiated in the circumferential direction. It includes not only a linearly extending portion and a bent portion as in the coil conductor 21 according to the present embodiment, but also a minimum portion of the coil conductor that continues to be bent. That is, the present invention is characterized in that the conductive member is disposed at a location where the radius of curvature of the coil conductor is relatively smaller than other locations, and is differentially (relatively between any two points) minimal. A bent portion as a portion is also included in the “minimum portion of the radius of curvature in the circumferential direction of the coil conductor” in the present invention.

  FIG. 3 is a cross-sectional view showing a coupling relationship between the coil antenna 101 and the coil antenna 201 of the coupling partner. In FIG. 3, the coil antenna 101 is a power feeding coil antenna, and the coupling partner coil antenna 201 is a power receiving coil antenna.

  As shown in FIG. 3, the area of the formation area of the coil antenna 101 that is the feeding coil antenna (the area of the formation area of the coil conductor in FIG. 2) is the formation area of the coil antenna 201 that is the coupling partner that is the receiving coil antenna. (Area of the coil conductor formation region). As shown in FIG. 3, the first conductive members 11 </ b> A, 11 </ b> B, etc. are arranged on the opposite side to the coupling partner coil antenna 201 with the coil conductor 31 interposed therebetween in the Z-axis direction. In other words, the first conductive members 11 </ b> A, 11 </ b> B and the like are disposed on the opposite side of the coil antenna 31 with respect to the coil conductor 31.

  Generally, the magnetic flux tends to be strong inside the portion with a small radius of curvature in the circumferential direction of the coil conductor. In particular, the magnetic flux tends to concentrate inside the minimum portion PS of the radius of curvature of the coil conductor, and the magnetic flux density is likely to be relatively higher than other portions of the coil conductor. On the other hand, in the coil antenna 101 according to the present embodiment, a part of the first conductive members 11A, 11B, 11C, and 11D has a coil conductor that tends to have a relatively high magnetic flux density when viewed from the Z-axis direction. It overlaps with the minimum portion PS of the radius of curvature of 31. Further, the first conductive members 11A, 11B, 11C, and 11D have extraction portions C1, C2, C3, and C4 that do not overlap the coil conductors 31 other than the minimal portion PS as viewed from the Z-axis direction. For this reason, the magnetic field formation in the minimal portion PS is partly hindered by the first conductive members 11A, 11B, 11C, and 11D, and variations in magnetic flux density formed by the coil conductor 31 are suppressed. Since the magnetic flux density formed by the coil conductor is uniform, variation in coupling strength due to the relative positional relationship with the coil antenna of the coupling partner is suppressed. Therefore, it is possible to realize a coil antenna having a stable coupling coefficient with the coil antenna of the coupling partner in a wide range of relative positional relationships by a simple structure.

  Further, in the present embodiment, each of the first conductive members 11A, 11B, 11C, and 11D overlaps with the plurality of minimum portions PS and extends in the radial direction of the coil conductor 31 as viewed from the Z-axis direction. It is. That is, the single first conductive member has a structure in which the plurality of minimum portions PS of the coil conductor 31 are overlapped when viewed from the Z-axis direction. Therefore, the above-described operations and effects can be achieved by simply providing a small number of first conductive members 11A, 11B, 11C, and 11D with a simple shape.

  In this embodiment, since the area of the formation area of the coil antenna 101 is larger than the area of the formation area of the coil antenna 201 that is the coupling partner, the position of the coil antenna 201 that is the coupling partner on the plane is free. The degree can be increased.

  In the present embodiment, the first conductive members 11 </ b> A, 11 </ b> B, 11 </ b> C, and 11 </ b> D are disposed on the side opposite to the coil antenna 201 that is the coupling partner with respect to the coil conductor 31. The first conductive members 11 </ b> A, 11 </ b> B, 11 </ b> C, and 11 </ b> D may be disposed on the coil antenna 201 side of the coupling partner with respect to the coil conductor 31, but are disposed on the opposite side of the coil antenna 31 of the coupling partner. It is desirable that When the first conductive members 11 </ b> A, 11 </ b> B, 11 </ b> C, and 11 </ b> D are arranged on the coil antenna 201 side of the coupling partner with respect to the coil conductor 31, the magnetic field coupling between the coil antenna 101 and the coil antenna 201 of the coupling partner is strongly hindered. It may be too much. However, the first conductive members 11 </ b> A, 11 </ b> B, 11 </ b> C, and 11 </ b> D are disposed on the side opposite to the coil antenna 201 that is the coupling partner with respect to the coil conductor 31, so that the coil conductor 31 and the coil antenna 201 that is the coupling partner are disposed. Compared with the case where the first conductive members 11A, 11B, 11C, and 11D are disposed, the coil antenna 101 is more easily magnetically coupled to the coil antenna 201 that is the coupling partner. In addition, with this configuration, it is possible to suppress the generation of parasitic capacitance with the coupling partner coil antenna 201 via the first conductive members 11A, 11B, 11C, and 11D.

  In the present embodiment, the first conductive members 11A, 11B, 11C, and 11D are shown as being configured to overlap the four minimal portions PS as viewed from the Z-axis direction, but the present invention is not limited to this. . In order to achieve the above-described functions and effects of the present invention, it is only necessary that the first conductive member overlaps one or more minimum portions PS as viewed from the Z-axis direction.

  In the present embodiment, an example of a coil antenna including four first conductive members 11A, 11B, 11C, and 11D that are rectangular flat plates has been described. However, the present invention is not limited to this configuration. The number, arrangement, and the like of the first conductive members can be changed as appropriate within the scope of the operation and effect of the present invention, as will be described in detail later. Further, the shape of the first conductive member is not limited to a rectangular flat plate, and can be changed as appropriate within a range where the effects and advantages of the present invention are achieved. The planar shape of the first conductive member may be, for example, a circle, an ellipse, a polygon, an L shape, or the like. Further, the first conductive member is not limited to a flat plate, may have a curved surface, and may have a three-dimensional structure or the like.

  In the above-described example, the operation in the case where the coil antenna 101 is a feeding coil antenna has been described, but the same holds true even if transmission and reception are reversed. That is, the same effect is obtained when the coil antenna 101 is a power receiving coil antenna. The same applies to coil antennas according to the following embodiments. Even when the coil antenna 101 is a power receiving coil antenna, the first conductive members 11A, 11B, 11C, and 11D are opposite to the coil antenna 201 (feeding coil antenna) to be coupled to the coil conductor 31. Placed in.

  Next, a power supply device of a wireless power supply system using the coil antenna 101 according to the present embodiment will be described with reference to the drawings. FIG. 4 is a cross-sectional view of a power feeding device 301 including the coil antenna 101 according to the first embodiment.

  The power feeding device 301 includes a resin cover 2, a coil antenna 101, a circuit board 4, a power feeding circuit (not shown), and the like. The power feeding device 301 is connected to another electronic device by a cable or the like.

  The resin cover 2 has a rectangular parallelepiped shape. As shown in FIG. 4, a coil antenna 101, a circuit board 4, a power feeding circuit, and the like are housed inside the resin cover 2. The circuit board 4 is a board having a ground conductor 5 formed therein, and is, for example, a printed wiring board.

  A power supply circuit or the like is mounted on the main surface of the circuit board 4, and the power supply circuit is connected to the first end and the second end of the coil conductor 31 via a conductor pattern (not shown). The power feeding circuit is a power feeding circuit for a power supply system such as a magnetic resonance power transmission system, and may further include a power receiving circuit.

  With this configuration, it is possible to realize a power feeding device of a wireless power supply system including a power feeding coil antenna with a small change in coupling strength due to a relative positional relationship with the coupling partner coil antenna.

  In the power supply apparatus shown in FIG. 4, the first conductive members 11 </ b> A, 11 </ b> B and the like are arranged between the coil conductor 31 and the circuit board 4. With this configuration, the magnetic shield effect on the back side of the first conductive members 11A, 11B, etc. (the lower side of the first conductive members 11A, 11B, etc. in FIG. 4) is obtained, and the circuit board 4 has a wiring pattern and a coil antenna. Unnecessary bonding with is suppressed. Also, with this configuration, it is possible to suppress the magnetic field generated from the coil conductor 31 from being radiated to the circuit board 4.

  In this embodiment, the coil antenna 101 is provided on a mouse pad or the like as a feeding coil antenna, and the coupling partner coil antenna is provided on the mouse as a power receiving coil antenna. However, the present embodiment is limited to this configuration. It is not a thing. As will be described in detail later, the coil antenna of the present invention is a coil antenna used for coupling a power feeding device and a power receiving device that constitute a wireless power supply system, and is provided in either or both of the power feeding device and the power receiving device. It is done.

  The first conductive members 11A, 11B, 11C, and 11D may be connected to the ground of the power feeding device or the power receiving device (for example, the ground of the circuit board) in order to function as a potential stability or an electric field shield. Further, the ground conductor of the circuit board may also be used as the first conductive members 11A, 11B, 11C, and 11D.

<< Second Embodiment >>
The second embodiment shows an example in which the structure of the coil conductor is different from that of the coil antenna 101 according to the first embodiment.

  FIG. 5A is a plan view of the coil antenna 102 according to the second embodiment, and FIG. 5B is a plan view of the coil antenna 102 showing a minimum portion PS of the radius of curvature in the circumferential direction of the coil conductor 32. is there. In FIG. 5A, in order to make the structure easy to understand, illustration of the base material 1 is omitted, and texture patterns are given to the first conductive members 12A and 12B. Further, in FIG. 5B, the first conductive members 12A and 12B are not shown for easy understanding of the structure.

  The coil antenna 102 according to the present embodiment is different from the coil antenna 101 according to the first embodiment in that a coil conductor 32 is provided. Further, the coil antenna 102 according to the present embodiment is different from the coil antenna 101 in that the first conductive members 12A and 12B are provided. Other configurations are substantially the same as those of the coil antenna 101.

  As shown in FIG. 5A, the coil conductor 32 according to the present embodiment is formed on the surface of the base material 1 and the like, and has an elliptical spiral shape of about 4 turns wound around the winding axis AX. The conductor pattern has a first end E1 and a second end E2. In this way, the “minimum portion of the radius of curvature” of the elliptical coil conductor is the semicircular portion at both ends (both end portions in the Y-axis direction of the coil conductor 32 in FIG. 5B) as viewed from the Z-axis direction. Become. In the present embodiment, the coil conductor 32 has two minimum portions PS having a radius of curvature in one turn.

  The two first conductive members 12A and 12B are rectangular flat plates. The first conductive members 12 </ b> A and 12 </ b> B overlap with the minimum portion PS of the radius of curvature in the circumferential direction of the coil conductor 32 as viewed from the Z-axis direction. In addition, the first conductive members 12A and 12B have extraction portions C1 and C2 that do not overlap with the coil conductors 32 other than the minimal portion PS when viewed from the Z-axis direction.

  Even in such a configuration, the basic configuration of the coil antenna 102 is the same as that of the coil antenna 101 according to the first embodiment, and has the same operations and effects as the coil antenna 101.

<< Third Embodiment >>
In the third embodiment, an example in which the structure of the coil conductor is different from the coil antenna according to each of the embodiments described above will be described.

  FIG. 6 is a plan view of the coil antenna 103 according to the third embodiment. FIG. 7A is a plan view of the coil conductor 33 showing the inner peripheral coil conductor part MP and the outer peripheral coil conductor part FP, and FIG. 7B shows the first coil conductor part CP1 and the second coil conductor part CP2. It is a top view of the coil conductor 33 which shows. In FIG. 6, in order to make the structure easy to understand, the base material 1 is not shown, and texture patterns are given to the first conductive members 11A, 11B, 11C, and 11D. In FIG. 7A, for easy understanding of the structure, the inner peripheral coil conductor part MP is indicated by a broken line, and the outer peripheral coil conductor part FP is indicated by a solid line. In FIG. 7B, in order to facilitate understanding of the structure, the first coil conductor portion CP1 is indicated by a broken line, and the second coil conductor portion CP2 is indicated by a one-dot chain line.

  The coil antenna 103 according to the present embodiment differs from the coil antenna 101 according to the first embodiment in that the coil antenna 33 is provided, and the other configuration is substantially the same as the coil antenna 101.

  As shown in FIG. 7A, the coil conductor 33 according to this embodiment includes an outer peripheral coil conductor portion FP and an inner peripheral coil conductor portion MP. The outer peripheral coil conductor portion FP is a rectangular spiral conductor pattern of about 3 turns wound clockwise from the outside toward the inside as viewed from the Z-axis direction (corresponding to the “first direction” in the present invention). It is. The inner coil conductor MP is a rectangular loop conductor pattern of about one turn that is wound counterclockwise (in the direction opposite to the first direction) as viewed from the Z-axis direction. Further, when viewed from the Z-axis direction, the distance L2 from the winding axis AX in the radial direction of the outer peripheral coil conductor portion FP is farther than the distance L1 from the winding axis AX in the radial direction of the inner peripheral coil conductor portion MP ( L2> L1).

  That is, the coil conductor 33 according to the present embodiment includes the outer peripheral coil conductor portion FP and the inner peripheral coil conductor portion MP positioned on the inner periphery of the outer peripheral coil conductor portion FP. The outer peripheral coil conductor part FP and the inner peripheral coil conductor part MP are wound in opposite directions, and the outer coil conductor part FP is wound more times than the inner coil conductor part MP.

  Here, the “inner peripheral coil conductor portion” in the present invention refers to a conductor portion that is wound an arbitrary number of times around the winding axis AX from the innermost periphery of the coil conductor. The “outer coil conductor part” in the present invention is a conductor part other than the inner periphery coil conductor part of the coil conductor, and means a conductor part located on the outer periphery of the inner periphery coil conductor part. Therefore, a coil conductor is comprised by the inner periphery coil conductor part and the outer periphery coil conductor part other than an inner periphery coil conductor part.

  Further, as shown in FIG. 7B, the coil conductor 33 according to this embodiment includes a first coil conductor portion CP1 having a short distance from the winding axis AX in the radial direction and a winding axis AX in the radial direction. Has a second coil conductor portion CP2 farther than the first coil conductor portion. The distance R2 from the winding axis AX in the radial direction of the second coil conductor portion CP2 is longer than the distance R1 from the winding axis AX in the radial direction of the first coil conductor portion CP1 (R2> R1). In the present embodiment, the first coil conductor portion CP1 is located on the innermost periphery of the coil conductor 33 and is a conductor of about one turn that is wound around the winding axis AX. In the present embodiment, the second coil conductor portion CP2 is located on the outer periphery of the first coil conductor portion CP1, and is a conductor of about two turns that is wound around the winding axis AX.

  The gap G1 between the coil conductors 33 adjacent to each other in the first coil conductor portion CP1 is larger than the gap G2 between the coil conductors 33 adjacent to each other in the second coil conductor portion CP2 (G1> G2). That is, in this embodiment, as viewed from the Z-axis direction, the coil conductor 33 is loosely wound in the first coil conductor portion CP1, and the coil conductor 33 is densely wound in the second coil conductor portion CP2. Become. Note that the coil conductors 33 are not necessarily adjacent to each other in the first coil conductor portion CP1. Further, the coil conductors 33 are not necessarily adjacent to each other in the second coil conductor portion CP2.

  Here, the “first coil conductor portion” in the present invention refers to a conductor portion of the coil conductor that is wound an arbitrary number of times around the winding axis AX. The “second coil conductor portion” in the present invention is a conductor portion that is located on the outer periphery of the inner peripheral coil conductor portion and is wound any number of times around the winding axis AX. The first coil conductor portion CP1 may not be the conductor located at the innermost circumference of the coil conductor 33, and the second coil conductor portion CP2 is a conductor located relatively at the outer circumference than the first coil conductor portion CP1. Good. The coil conductor may include another conductor portion other than the first coil conductor portion CP1 and the second coil conductor portion CP2.

  The coil antenna 103 according to the present embodiment has the following effects in addition to the effects described in the first embodiment.

  In the present embodiment, when viewed from the Z-axis direction, the inner circumference (inner circumference coil conductor portion MP) of the coil conductor 33 and the outer circumference (outer circumference coil conductor portion FP) of the coil conductor 33 are wound in opposite directions, and The inner circumference of the coil conductor 33 has fewer turns than the outer circumference of the coil conductor 33. Therefore, a magnetic flux in a direction opposite to the magnetic flux contributing to the magnetic field coupling with the coupling partner coil antenna (the magnetic flux generated from the outer coil conductor portion FP) is generated from the inner circumferential coil conductor portion MP of the coil conductor 33, and the coupling is performed. Part of the magnetic flux contributing to magnetic field coupling with the counterpart coil antenna is canceled out. That is, with this configuration, the magnetic flux density on the inner circumference of the coil conductor, which tends to increase the magnetic flux density, is suppressed, the magnetic flux density formed by the coil conductor becomes uniform, and depends on the relative positional relationship with the coil antenna of the coupling partner. Variation in bond strength is suppressed.

  In the present embodiment, when viewed from the Z-axis direction, the coil conductor 33 is sparsely wound on the inner circumference (first coil conductor portion CP1) where the magnetic flux density tends to be high, and the magnetic flux density is likely to be low (the first circumference). In the two-coil conductor portion CP2), the coil conductor 33 is tightly wound. In other words, the portion where the distance between the coil conductors 33 is dense is located closer to the outer periphery from the winding axis AX in the radial direction, and the sparse portion is located closer to the inner periphery from the winding axis AX in the radial direction. . 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) and weaker as it is farther from the winding axis (coil center). However, since the coil antenna 103 is wound such that the distance between the coil conductors L1 and L2 becomes closer toward the outer periphery from the winding axis AX in the radial direction, on the upper surface (or lower surface) of the coil antenna, The winding axis direction component of the magnetic flux density is uniform. Therefore, this configuration suppresses variations in coupling strength due to the relative positional relationship with the coil antenna of the coupling partner, and stabilizes the coupling coefficient with the coil antenna of the coupling partner in a wide range of relative positional relationships. Coil antenna can be realized.

  In this embodiment, the outer coil conductor portion FP is an approximately two-turn conductor portion and the inner coil conductor portion MP is an approximately two-turn conductor portion. However, the present embodiment is limited to this configuration. is not. The number of turns of the outer peripheral coil conductor part FP and the number of turns of the inner peripheral coil conductor part MP can be changed as appropriate within the scope of the operation and effect of the present invention.

  In the present embodiment, the first coil conductor portion CP1 is a conductor portion of about 1 turn and the second coil conductor portion CP2 is a conductor portion of about 2 turns. However, the present embodiment is limited to this configuration. It is not a thing. The number of turns of the first coil conductor portion CP1 and the number of turns of the second coil conductor portion CP2 can be changed as appropriate within the scope of the operation and effect of the present invention.

<< Fourth Embodiment >>
In the fourth embodiment, a coil antenna further including a second conductive member is shown.

  FIG. 8A is a plan view of the coil antenna 104 according to the fourth embodiment, and FIG. 8B is a plan view of the coil conductor 31 showing the inner peripheral coil conductor portion MP and the outer peripheral coil conductor portion FP. is there. FIG. 9 is a cross-sectional view showing a coupling relationship between the coil antenna 104 and the coil antenna 201 of the coupling partner. In FIG. 8A, in order to make the structure easy to understand, the base material 1 is not shown, and the first conductive members 11A, 11B, 11C, 11D and the second conductive member 24 have texture patterns. Has been granted. Further, in FIG. 8B, in order to make the structure easy to understand, the inner peripheral coil conductor part MP is indicated by a broken line, and the outer peripheral coil conductor part FP is indicated by a solid line. In FIG. 9, the coil antenna 104 is a power feeding coil antenna, and the coupling partner coil antenna 201 is a power receiving coil antenna.

  The coil antenna 104 according to the present embodiment is different from the coil antenna 101 according to the first embodiment in that it further includes a second conductive member 24. Other configurations are substantially the same as those of the coil antenna 101.

  The coil conductor 31 according to the present embodiment has an inner peripheral coil conductor part MP and an outer peripheral coil conductor part FP. In the present embodiment, the outer peripheral coil conductor portion FP is a conductor of about two turns that is located on the outermost periphery of the coil conductor 31 and is wound around the winding axis AX. Further, in the present embodiment, the inner peripheral coil conductor portion MP is located on the inner periphery of the outer peripheral coil conductor portion FP, and is a conductor of about 2 turns wound around the winding axis AX.

  The second conductive member 24 is a rectangular flat plate. A part of the second conductive member 24 overlaps the coil conductor 31 when viewed from the Z-axis direction. The second conductive member 24 overlaps the coil opening CM and the inner peripheral coil conductor part MP as viewed from the Z-axis direction. Further, the second conductive member 24 does not overlap the outer peripheral coil conductor portion FP when viewed from the Z-axis direction. The second conductive member 24 is a flat plate made of, for example, metal or graphite.

  As shown in FIG. 9, the second conductive member 24 is disposed on the opposite side to the coil antenna 201 to be coupled with the coil conductor 31 sandwiched in the Z-axis direction. In other words, the second conductive member 24 is disposed on the side opposite to the coil antenna 201 that is the coupling partner with respect to the coil conductor 31. In the present embodiment, the second conductive member 24 is disposed between the first conductive members 11A and 11B and the coil conductor 31 with respect to the Z-axis direction.

  In the present embodiment, when viewed from the Z-axis direction, the second conductive member 24 overlaps the inner circumference (inner circumference coil conductor portion MP) and the coil opening CM of the coil conductor 31 where the magnetic flux density tends to be high, and the magnetic flux density is low. The second conductive member 24 does not overlap the outer periphery of the coil conductor 31 that is likely to be formed (the outer peripheral coil conductor portion FP). Therefore, the magnetic field formation at the inner periphery of the coil conductor 31 and the coil opening CM is partly hindered by the second conductive member 24, and variations in magnetic flux density formed by the coil conductor 31 are suppressed. Since the magnetic flux density formed by the coil conductor is uniform, variation in coupling strength due to the relative positional relationship with the coil antenna 201 of the coupling partner is further suppressed.

  The second conductive member 24 is preferably arranged on the opposite side to the coil antenna 201 to be coupled to the coil conductor 31 in the same manner as the first conductive members 11A, 11B, 11C, and 11D. This configuration makes it easier for the coil antenna 104 to be magnetically coupled to the coil antenna 201 to be coupled than when the second conductive member 24 is disposed between the coil conductor 31 and the coil antenna 201 to be coupled.

  In the present embodiment, the example in which the second conductive member 24 is disposed between the first conductive members 11A and 11B and the coil conductor 31 with respect to the Z-axis direction has been described. However, the present embodiment is limited to this configuration. It is not something. The second conductive member 24 may be disposed on the same plane as the first conductive member with respect to the Z-axis direction, and is further away from the coil conductor 31 than the first conductive member with respect to the Z-axis direction. It may be arranged at a position.

<< Fifth Embodiment >>
In the fifth embodiment, a coil antenna provided with differently shaped first conductive members will be described.

  FIG. 10A is a plan view of the coil antenna 105 according to the fifth embodiment, and FIG. 10B is a plan view of the coil conductor 31 showing the inner peripheral coil conductor portion MP and the outer peripheral coil conductor portion FP. is there. FIG. 11 is a cross-sectional view showing a coupling relationship between the coil antenna 105 and the coupling partner coil antenna 201. In FIG. 10A, the base material 1 is not shown in order to make the structure easy to understand, and a texture pattern is given to the first conductive member 15. Further, in FIG. 10B, in order to make the structure easy to understand, the inner peripheral coil conductor part MP is indicated by a broken line, and the outer peripheral coil conductor part FP is indicated by a solid line. In FIG. 11, the coil antenna 105 is a power feeding coil antenna, and the coil antenna 201 to be coupled is a power receiving coil antenna.

  The coil antenna 105 according to the present embodiment is different from the coil antenna 101 according to the first embodiment in the shape of the first conductive member 15. Other configurations are substantially the same as those of the coil antenna 101.

  The coil conductor 31 according to the present embodiment has an inner peripheral coil conductor part MP and an outer peripheral coil conductor part FP. In the present embodiment, the outer peripheral coil conductor portion FP is a conductor of about two turns that is located on the outermost periphery of the coil conductor 31 and is wound around the winding axis AX. Further, in the present embodiment, the inner peripheral coil conductor portion MP is located on the inner periphery of the outer peripheral coil conductor portion FP, and is a conductor of about 2 turns wound around the winding axis AX.

  As viewed from the Z-axis direction, the first conductive member 15 includes a first conductive member (first conductive members 11A, 11B, 11C, and 11D in FIG. 8A) and a second embodiment according to the fourth embodiment. The shape is such that the conductive member (the second conductive member 24 in FIG. 8A) is integrated.

  The first conductive member 15 has a portion that overlaps the plurality of minimal portions PS and extends in the radial direction of the coil conductor 31 when viewed from the Z-axis direction. Further, the first conductive member 15 overlaps with the coil opening CM and the inner peripheral coil conductor part MP and does not overlap with the outer peripheral coil conductor part FP when viewed from the Z-axis direction.

  In the present embodiment, when viewed from the Z-axis direction, the first conductive member 15 overlaps the inner circumference (inner circumference coil conductor portion MP) and the coil opening CM of the coil conductor 31 where the magnetic flux density tends to be high, and the magnetic flux density is low. The first conductive member 15 does not overlap the outer periphery of the coil conductor 31 that is likely to be formed (the outer peripheral coil conductor portion FP). Therefore, magnetic field formation at the inner circumference of the coil conductor 31 and the coil opening CM is partially hindered by the first conductive member 15, and variations in magnetic flux density formed by the coil conductor 31 are suppressed. Since the magnetic flux density formed by the coil conductor is uniform, variation in coupling strength due to the relative positional relationship with the coil antenna 201 of the coupling partner is suppressed.

<< Sixth Embodiment >>
In the sixth embodiment, a coil antenna including an axially symmetric coil conductor will be described.

  FIG. 12 is a plan view of a coil antenna 106 according to the sixth embodiment. FIG. 13A is a plan view of the coil conductor 36 showing the inner peripheral coil conductor part MP and the outer peripheral coil conductor part FP, and FIG. 13B shows the first coil conductor part CP1 and the second coil conductor part CP2. It is a top view of the coil conductor 36 which shows. In FIG. 12, in order to make the structure easy to understand, the substrate 1 is not shown, and texture patterns are given to the first conductive members 11A, 11B, 11C, and 11D. In FIG. 13A, the inner peripheral coil conductor portion MP is indicated by a broken line, and the outer peripheral coil conductor portion FP is indicated by a solid line. In FIG. 13B, in order to facilitate understanding of the structure, the first coil conductor portion CP1 is indicated by a broken line, and the second coil conductor portion CP2 is indicated by a solid line.

  The coil antenna 106 according to the present embodiment differs from the coil antenna 101 according to the first embodiment in that it includes a coil conductor 36 that is axially symmetric, and the other configuration is substantially the same as the coil antenna 101.

  The coil conductor 36 according to the present embodiment is line symmetric with respect to an axis (symmetry axis) SA passing between the first end E1 and the second end E2 when viewed from the Z-axis direction. In addition, the coil conductor 36 has intersecting portions CR1 and CR2 that intersect each other so that the inner and outer arrangements of adjacent coil conductors are interchanged. These intersecting portions CR1 and CR2 intersect via an insulating layer so that adjacent coil conductors are not short-circuited.

  As shown in FIG. 13A, the coil conductor 36 according to this embodiment includes two outer peripheral coil conductor portions FP and an inner peripheral coil conductor portion MP. The two outer peripheral coil conductor portions FP are conductor patterns of about 1.5 turns wound clockwise (first direction) when viewed from the Z-axis direction. The inner peripheral coil conductor portion MP is a rectangular loop-shaped conductor pattern of about one turn that is wound counterclockwise (in the direction opposite to the first direction) as viewed from the Z-axis direction.

  As shown in FIG. 13B, the coil conductor 36 according to the present embodiment includes a first coil conductor portion CP1 having a short distance from the winding axis AX in the radial direction and a winding axis AX in the radial direction. Has a second coil conductor portion CP2 farther than the first coil conductor portion. In the present embodiment, the first coil conductor portion CP1 is located at the innermost periphery of the coil conductor 36, and is a conductor of about 2 turns that is wound around the winding axis AX. In the present embodiment, the second coil conductor portion CP2 is located on the outer periphery of the first coil conductor portion CP1, and is two conductors of about one turn wound around the winding axis AX. As viewed from the Z-axis direction, the coil conductor 36 is loosely wound in the first coil conductor portion CP1, and the coil conductor 36 is densely wound in the second coil conductor portion CP2.

  In general, coil conductors wound symmetrically have a problem that the effect of line capacitance between adjacent coil conductors increases due to connection with a power feeding circuit (or power receiving circuit). This problem is prominent in the outer peripheral portion (second coil conductor portion CP2) of the coil antenna having the inner peripheral portion in which the coil conductor is wound loosely and the outer peripheral portion in which the coil conductor is wound densely. On the other hand, in this embodiment, since the inner peripheral coil conductor portion MP wound in the direction opposite to the outer peripheral coil conductor portion FP is provided, the magnetic flux density of the inner peripheral portion of the coil conductor that tends to increase the magnetic flux density is increased. Is suppressed (see the second embodiment). That is, with this configuration, the coil conductor 36 is not tightly wound around the second coil conductor portion CP2 (the gap G2 between the coil conductors 36 is reduced) compared to the case where the inner peripheral coil conductor portion MP is not provided. In other words, it is possible to realize a coil antenna that suppresses variation in coupling strength due to a relative positional relationship with the coil antenna of the coupling partner.

  In the present embodiment, the coil conductor 36 is line symmetric with respect to an axis (symmetry axis) SA passing between the first end E1 and the second end E2 when viewed from the Z-axis direction. The distribution of the line capacitance between adjacent coil conductors is targeted, and the uniformity of the magnetic field radiation of the coil antenna is ensured. Further, when the power feeding circuit (or power receiving circuit) connected to the coil antenna 106 is a balanced circuit, the balance as viewed from the power feeding circuit (or power receiving circuit) can be maintained.

<< Seventh Embodiment >>
In the seventh embodiment, a coil antenna including coil conductors having different line widths (conductor diameters) will be described.

  FIG. 14 is a plan view of a coil antenna 107 according to the seventh embodiment. FIG. 15A is a plan view of the coil conductor 37 showing the inner peripheral coil conductor part MP and the outer peripheral coil conductor part FP, and FIG. 15B shows the first coil conductor part CP1 and the second coil conductor part CP2. It is a top view of the coil conductor 37 which shows. In FIG. 14, in order to make the structure easy to understand, the substrate 1 is not shown, and texture patterns are given to the first conductive members 11A, 11B, 11C, and 11D. In FIG. 15A, the inner peripheral coil conductor part MP is indicated by a broken line, and the outer peripheral coil conductor part FP is indicated by a solid line. In FIG. 15B, in order to facilitate understanding of the structure, the first coil conductor portion CP1 is indicated by a broken line, and the second coil conductor portion CP2 is indicated by a solid line.

  The coil antenna 107 according to the present embodiment is different from the coil antenna 106 according to the sixth embodiment in that the line width of the first coil conductor portion CP1 of the coil conductor 37 is different from the line width of the second coil conductor portion CP2. Unlike the coil antenna 106, other configurations are substantially the same.

  As shown in FIG. 14 and the like, in the coil conductor 37 according to this embodiment, the line width of the first coil conductor portion CP1 is larger than the line width of the second coil conductor portion CP2.

  In the present embodiment, since the line width of a part of the coil conductor 37 is thick (since the conductor diameter is large), the DC resistance component of the entire coil antenna can be reduced.

  In the present embodiment, the gap G1 between the coil conductors 37 adjacent to each other in the first coil conductor part CP1 having a large line width is the gap G2 between the coil conductors 37 adjacent to each other in the other part (second coil conductor part CP2). (G1> G2). Therefore, even if the line width of the inner peripheral part (first coil conductor part CP1) around which the coil conductor 37 is sparsely wound is thicker than the line width of other parts, the line-to-line capacitance between adjacent coil conductors There is little increase.

  The inductance value of the coil antenna is lower when the line width of the coil conductor is thicker than when the line width of the coil conductor constituting the coil antenna is narrow. Therefore, with the above configuration, the inductance value of the entire coil antenna is lower than when the line width of the entire coil conductor 37 is the same. Therefore, if it is a coil antenna of the same inductance value, the number of turns such as the outer peripheral part around which the coil conductor is tightly wound can be further increased by the above configuration.

<< Eighth Embodiment >>
In the eighth embodiment, an example of a coil antenna further including a magnetic member is shown.

  FIG. 16A is a plan view of the coil antenna 108 according to the eighth embodiment, and FIG. 16B is a plan view of the coil antenna 108 showing the minimum portion PS of the radius of curvature in the circumferential direction of the coil conductor 31. is there. In FIG. 16A, in order to make the structure easy to understand, the base material 1 is not shown, a texture pattern is given to the first conductive members 11A, 11B, 11C, and 11D, and the magnetic member 48A. , 48B, 48C, 48D are given cross hatching. Further, in FIG. 16B, the first conductive members 11A, 11B, 11C, and 11D are not shown for easy understanding of the structure.

  The coil antenna 108 according to the present embodiment is different from the coil antenna 101 according to the first embodiment in that it further includes four magnetic members 48A, 48B, 48C, and 48D. Other configurations are substantially the same as those of the coil antenna 101.

  The magnetic members 48A and 48C are trapezoidal flat plates, and the magnetic members 48B and 48D are triangular flat plates. The magnetic members 48A, 48B, 48C, and 48D overlap the punched portions C1, C2, C3, and C4 shown in FIG. 16B when viewed from the Z-axis direction. That is, the magnetic members 48A, 48B, 48C, and 48D are respectively disposed in the punched portions C1, C2, C3, and C4. The magnetic members 48A, 48B, 48C, and 48D are, for example, sintered magnetic ferrite plates. A resin sheet in which magnetic powder such as ferrite powder is dispersed in a resin such as an epoxy resin is used as the base material 1. It may be affixed.

  In general, the magnetic flux density tends to be relatively low in other portions of the coil conductor as compared with the minimum portion PS of the radius of curvature of the coil conductor. In the present embodiment, the magnetic members 48A, 48B, 48C, and 48D are disposed in other portions (extracted portions C1, C2, C3, and C4) where the magnetic flux density tends to be relatively low. Variation in magnetic flux density due to the positional relationship is suppressed. Also, with this configuration, the coil antenna itself can be downsized because the inductance value of the coil antenna increases compared to the case where no magnetic member is provided.

  The magnetic member is preferably arranged on the opposite side of the coil conductor 31 from the coil antenna of the coupling partner. Thereby, the coil antenna of the present invention is easily magnetically coupled to the coil antenna of the coupling partner. Further, the shape, the number, and the like of the magnetic member are not limited to those shown in the present embodiment. The shape, number, and the like of the magnetic member can be appropriately changed within the range where the functions and effects of the present invention are exhibited. That is, the magnetic member may be, for example, rectangular, circular, or the like, and the coil antenna may be configured to include one magnetic member.

<< Ninth embodiment >>
In the ninth embodiment, an example of a wireless power supply system using the coil antenna of the present invention is shown.

  The “power supply device” in the present invention is a device including the coil antenna and a power supply circuit (described in detail later), and is, for example, the mouse pad corresponding to a wireless power supply system such as a magnetic resonance power supply system. A “power receiving device” in the present invention is a device including the coil antenna and a power receiving circuit (described in detail later), and for example, a power receiving side device (wireless mouse, Mobile phone terminals, so-called smartphones, tablet terminals, notebook PCs and PDAs, wearable terminals, cameras, videos, game machines, toys, and the like).

  The magnetic resonance power supply system is used in the HF band, particularly in the vicinity of 6.78 MHz. Further, the magnetic field type wireless power supply system couples with a power supply partner by magnetic field coupling and supplies power.

  FIG. 17 is a circuit diagram of a wireless power supply system 501 according to the ninth embodiment. The wireless power supply system 501 includes a power feeding device 301 and a power receiving device 401, and supplies power from the power feeding device 301 to the power receiving device 401 wirelessly.

  The power feeding device 301 includes a power feeding circuit 310, a power feeding coil antenna Lt connected to the power feeding circuit 310, and a resonance capacitor Ct connected in series to the power feeding coil antenna Lt. The power feeding coil antenna Lt is used for coupling with a power receiving circuit 410 included in the power receiving device 401, and the power feeding coil antenna Lt and the resonance capacitor Ct constitute a resonance circuit 320.

  The power feeding circuit 310 includes an inverter circuit 311 that converts the DC input voltage Vi into an AC voltage and applies the AC voltage to the resonance circuit 320. Inverter circuit 311 includes switching elements Q1 and Q2, a capacitor C11, a diode D1, and a drive circuit 312. The drive circuit 312 drives the switching elements Q1 and Q2 alternately on / off at an HF band operating frequency (eg, 6.78 MHz). The resonant frequency of the resonant circuit 320 is this operating frequency or a frequency in the vicinity thereof. In this way, the power feeding circuit 310 applies an alternating voltage in the HF band to the power feeding coil antenna Lt.

  The power receiving device 401 includes a power receiving circuit 410 and a power receiving coil antenna Lr connected to the power receiving circuit 410. The power receiving coil antenna Lr is used for coupling to a power feeding circuit 310 included in the power feeding device 301, and a resonance circuit 420 is configured by the inductance component of the power receiving coil antenna Lr and the capacitance component of the power receiving circuit 410. The power receiving coil antenna Lr and the power feeding coil antenna Lt are mainly magnetically coupled. In the present embodiment, as in the structure shown in the first embodiment, the area of the formation region of the feeding coil antenna Lt is larger than the area of the formation region of the power receiving coil antenna Lr.

  The power receiving circuit 410 includes a rectifying / smoothing circuit 411 that converts an AC voltage generated in the power receiving coil antenna Lr into a DC voltage, and a load Ro that is driven by the DC output voltage converted by the rectifying / smoothing circuit 411. The rectifying / smoothing circuit 411 includes a rectifying circuit 412 using a diode bridge circuit, smoothing capacitors C21 and C22, and a voltage regulator circuit 413.

  The resonant circuit 420 resonates at the above operating frequency in the HF band or at a frequency in the vicinity thereof. The resonance voltage of the resonance circuit 420 is full-wave rectified by the rectification circuit 412, smoothed and stabilized by the smoothing capacitors C21 and C22, and the voltage regulator circuit 313, and a predetermined constant voltage Vo is supplied to the load Ro.

  In the present embodiment, the feeding coil antenna Lt is the coil antenna 101 having the structure shown in the first embodiment, and the power receiving coil antenna Lr is a normal coil antenna. Note that the “ordinary coil antenna” means that the coil conductor has a simple loop shape or spiral shape.

  The feeding coil antenna may be a normal coil antenna, and the receiving coil antenna may be the coil antenna 101 shown in the first embodiment. Further, both the power feeding coil antenna and the power receiving coil antenna may be the coil antenna 101 having the structure shown in the first embodiment. In either case, the power feeding coil antenna and the power receiving coil antenna are mainly magnetically coupled, and power is transmitted mainly via the magnetic field.

  Thus, the coil antenna of the present invention can be used for both a power feeding coil antenna and a power receiving coil antenna.

  With this configuration, it is possible to realize a power feeding device, a power receiving device, and a wireless power supply system including a coil antenna with a small change in coupling strength due to a relative positional relationship with the counterpart coil antenna.

  In the present embodiment, an example in which a resonance circuit is configured by the capacitance component of the power reception circuit 410 and the inductance component of the power reception coil antenna Lr has been described. However, a resonance capacitor is parallel to the power reception coil antenna Lr. You may connect to.

<< Other Embodiments >>
In each embodiment shown above, although the example in which the first conductive member and the second conductive member are flat plates made of metal, graphite, or the like has been described, the present invention is not limited to this configuration. The first conductive member and the second conductive member may be a conductor pattern such as Cu formed inside or on the back surface of the substrate 1. Further, the first conductive member and the second conductive member may be a conductor formed on the circuit board, a ground conductor, a shield case, a battery pack, or the like. In addition, when the conductor formed on the circuit board, the ground conductor, the shield case, the battery pack, or the like is used as the first conductive member or the second conductive member, the first conductive member or the second conductive member is used. Is not required to be separately formed, and manufacturing is easy and cost reduction can be achieved.

  Note that the first conductive member may be a mesh-like conductor. By using the first conductive member as a mesh-like conductor, deterioration of antenna characteristics due to parasitic capacitance generated between the first conductive member and the coil conductor is suppressed. The same applies to the second conductive member.

  In each embodiment shown above, although the base material 1 showed the example which is a rectangular flat plate, it is not limited to this structure. The planar shape of the substrate 1 can be changed as appropriate, such as a circle, an ellipse, a square, and a polygon. Moreover, the base material 1 is not limited to a flat plate, may have a curved surface, and may have a three-dimensional structure or the like.

  In each of the embodiments described above, the example in which the coil conductor 31 is a rectangular spiral conductor pattern of about 4 turns formed on the surface of the base material 1 has been described. However, the present invention is not limited to this configuration. The outer shape of the coil conductor 31 can be appropriately changed to a circular shape, an elliptical shape, a polygonal shape, an L shape, a T shape, or the like as viewed from the Z-axis direction. Further, the coil conductor 31 may be formed on the back surface or inside of the substrate 1. The coil conductor 31 may have a helical structure in which a base material on which a spiral conductor pattern is formed is laminated. The coil conductor 31 may be a winding coil. That is, the base material is not essential in the coil antenna of the present invention. Note that the number of turns of the coil conductor 31 can also be changed as appropriate within the scope of the effects and advantages of the present invention.

  Finally, the description of the above embodiment is illustrative in all respects and not restrictive. Modifications and changes can be made as appropriate by those skilled in the art. 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.

AX ... winding shafts 31, 32, 33, 36, 37 ... coil conductor E1 ... first end E2 of coil conductor ... second end CM of coil conductor ... coil openings C1, C2, C3, C4 ... unplug CP1 ... 1st coil conductor part CP2 ... 2nd coil conductor part FP ... Outer periphery coil conductor part MP ... Inner circumference coil conductor part CR1, CR2 ... Intersection G1, G2 ... Gap PS of coil conductors adjacent to each other ... Circumferential direction of coil conductor L1, L2, R1, R2 of the radius of curvature at the distance Lr from the winding axis in the radial direction ... Power receiving coil antenna Lt ... Power feeding coil antenna C11 ... Capacitors C21, C22 ... Smoothing capacitor Ct ... Resonance capacitor D1 ... Diodes Q1, Q2 ... Switching element Ro ... Load Vi ... DC input voltage Vo ... Constant voltage 1 ... Base material 2 ... Resin cover 4 ... Circuit board 5 ... Ground conductor 11A, 11B, 11C, 11D, 12A, 12B, 15 ... first conductive member 24 ... second conductive member 101, 102, 103, 104, 105, 106, 107, 108 ... coil antenna 201 ... coupling partner coil Antenna 301 ... Power feeding device 310 ... Power feeding circuit 311 ... Inverter circuit 312 ... Drive circuit 313 ... Voltage regulator circuit 320 ... Resonant circuit 401 ... Power receiving device 410 ... Power receiving circuit 411 ... Rectifier smoothing circuit 412 ... Rectifier circuit 413 ... Voltage regulator circuit 420 ... Resonant circuit 501 Wireless power supply system

Claims (20)

A coil antenna used in a wireless power supply system,
A coil conductor wound a plurality of times around a winding axis;
A first conductive member that is at least partially overlapped with a minimal portion of a radius of curvature in the circumferential direction of the coil conductor, as viewed from the winding axis direction;
With
The said 1st electroconductive member is a coil antenna which has the extraction part which does not overlap with the said coil conductors other than the said minimum part seeing from the said winding axis direction.   2. The coil antenna according to claim 1, wherein the first conductive member overlaps a plurality of the minimum portions and extends in a radial direction of the coil conductor as viewed from the winding axis direction.   3. The coil antenna according to claim 1, wherein the coil conductor is line-symmetric with respect to an axis passing through the two end portions and intersecting the winding axis when viewed from the winding axis direction. The coil conductor includes an outer peripheral coil conductor portion wound in a first direction and an inner peripheral coil conductor portion wound in a direction opposite to the first direction when viewed from the winding axis direction. And
When viewed from the winding axis direction, the outer circumferential coil conductor portion is farther from the winding axis in the radial direction than the inner circumferential coil conductor portion,
The coil antenna according to any one of claims 1 to 3, wherein the number of turns of the outer peripheral coil conductor portion is greater than the number of turns of the inner peripheral coil conductor portion. The coil conductor includes a first coil conductor portion that is close to the winding axis in the radial direction and a second coil conductor portion that is farther from the winding axis in the radial direction than the first coil conductor portion. And having
5. The coil antenna according to claim 1, wherein a gap between the coil conductors adjacent to each other is larger in the first coil conductor portion than in the second coil conductor portion.   The coil antenna according to claim 5, wherein a line width of the first coil conductor portion is larger than a line width of the second coil conductor portion. A second conductive member that is at least partially overlapped with the coil conductor as viewed from the winding axis direction;
The coil conductor includes a first coil conductor portion that is close to the winding axis in the radial direction and a second coil conductor portion that is farther from the winding axis in the radial direction than the first coil conductor portion. And having
The coil according to any one of claims 1 to 6, wherein the second conductive member overlaps the first coil conductor portion and does not overlap the second coil conductor portion when viewed from the winding axis direction. antenna.   The coil antenna according to any one of claims 1 to 7, wherein the first conductive member is a mesh-shaped conductor.   The coil antenna according to claim 7 or 8, wherein the second conductive member is a mesh-shaped conductor.   The coil antenna according to any one of claims 1 to 9, wherein the coil conductor has a rectangular spiral shape having four minimum portions of a radius of curvature in one turn. A power feeding device in a wireless power supply system that wirelessly supplies power from a power feeding device to a power receiving device,
A coil antenna for feeding used for coupling with the power receiving device;
A feeding circuit connected to the feeding coil antenna;
With
The feeding coil antenna is
A coil conductor wound a plurality of times around a winding axis;
A first conductive member that is at least partially overlapped with a minimal portion of a radius of curvature in the circumferential direction of the coil conductor, as viewed from the winding axis direction;
With
The power supply device, wherein the first conductive member has a cutout portion that does not overlap the coil conductor other than the minimum portion when viewed from the winding axis direction.   The power feeding device according to claim 11, wherein the power feeding circuit applies an HF band alternating voltage to the power feeding coil antenna. A power receiving device in a wireless power supply system that wirelessly supplies power from a power feeding device to a power receiving device,
A power receiving coil antenna used for coupling with the power feeding device;
A power receiving circuit connected to the power receiving coil antenna;
With
The power receiving coil antenna is:
A coil conductor wound a plurality of times around a winding axis;
A first conductive member that is at least partially overlapped with a minimal portion of a radius of curvature in the circumferential direction of the coil conductor, as viewed from the winding axis direction;
With
The first conductive member is a power receiving device having a pull-out portion that does not overlap the coil conductor other than the minimal portion when viewed from the winding axis direction. A resonance circuit is constituted by a capacitance component of the power reception circuit and an inductance component of the power reception coil antenna,
The power receiving device according to claim 13, wherein a resonance frequency of the resonance circuit is an HF band frequency. In a wireless power supply system composed of a power feeding device and a power receiving device,
The power supply device
A power feeding coil antenna used for coupling with a power receiving coil antenna included in the power receiving device;
A feeding circuit connected to the feeding coil antenna;
Have
The feeding coil antenna is
A coil conductor wound a plurality of times around a winding axis;
A first conductive member that is at least partially overlapped with a minimal portion of a radius of curvature in the circumferential direction of the coil conductor, as viewed from the winding axis direction;
With
The first conductive member has a cut-out portion that does not overlap the coil conductor other than the minimal portion when viewed from the winding axis direction;
The wireless power supply system, wherein an area of the power feeding coil antenna is larger than an area of the power receiving coil antenna.   The wireless power supply system according to claim 15, wherein the first conductive member is disposed on a side opposite to the coil antenna for receiving power with respect to the coil conductor.   The wireless power supply system according to claim 15 or 16, wherein the power feeding circuit applies an alternating voltage of an HF band to the coil antenna for power feeding. In a wireless power supply system composed of a power feeding device and a power receiving device,
The power receiving device is:
A power receiving coil antenna used for coupling with a power feeding coil antenna included in the power feeding device;
A power receiving circuit connected to the power receiving coil antenna;
Have
The power receiving coil antenna is:
A coil conductor wound a plurality of times around a winding axis;
A first conductive member that is at least partially overlapped with a minimal portion of a radius of curvature in the circumferential direction of the coil conductor, as viewed from the winding axis direction;
With
The first conductive member has a cut-out portion that does not overlap the coil conductor other than the minimal portion when viewed from the winding axis direction;
The wireless power supply system, wherein an area of the power feeding coil antenna is larger than an area of the power receiving coil antenna.   19. The wireless power supply system according to claim 18, wherein the first conductive member is disposed on a side opposite to the coil antenna for feeding with respect to the coil conductor. A resonance circuit is constituted by a capacitance component of the power reception circuit and an inductance component of the power reception coil antenna,
The wireless power supply system according to claim 18 or 19, wherein a resonance frequency of the resonance circuit is a frequency in an HF band.

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