JP6642699B2 - Coil antenna, power supply device, power receiving device, and wireless power supply system - Google Patents

Description

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

  2. Description of the Related Art Conventionally, 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 is known (Patent Document 1).

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

Japanese Patent No. 5221111

  However, simply adopting the above structure for a coil antenna causes a parasitic capacitance between the coil conductors in a portion where the coil conductor is densely wound, and thus the relative position between the coil antenna and the coil antenna of the coupling partner is actually increased. It is difficult to configure a coil antenna that suppresses variation in coupling strength due to the relationship.

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

(1) The coil antenna of the present invention is used for a wireless power supply system,
A coil conductor wound multiple times around a winding axis;
A first conductive member that at least partially overlaps a minimum portion of a radius of curvature in a circumferential direction of the coil conductor when viewed from the winding axis direction;
With
The coil antenna, wherein the first conductive member has a cutout portion that does not overlap with the coil conductor other than the minimum portion when viewed from the winding axis direction.

  Generally, the magnetic flux tends to concentrate inside the minimum portion of the radius of curvature in the circumferential direction of the coil conductor, and the magnetic flux density tends to be relatively high as compared with 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 where the magnetic flux density tends to be relatively high, and the magnetic flux density is relatively high. The first conductive member does not overlap other than the extremely small portion of the coil conductor, which is likely to be low. Therefore, the formation of the magnetic field in the minimum portion is partially prevented by the first conductive member, and variation in the coupling strength due to the relative positional relationship with the coil antenna of the coupling partner is suppressed. Therefore, with a simple structure, it is possible to realize a coil antenna in which the coupling coefficient with the coupling partner coil antenna is stabilized in a wide range of relative positional relationship.

(2) In the above (1), it is preferable that the first conductive member overlaps the plurality of the minimum parts and extends in the radial direction of the coil conductor when viewed from the winding axis direction. This configuration has a structure in which a single first conductive member overlaps a plurality of minimum portions of the coil conductor when 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 line-symmetric with respect to an axis passing between the two ends and intersecting with the winding axis, as viewed from the winding axis direction. Is preferred. With this configuration, 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. Further, 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), when viewed from the winding axis direction, the coil conductor may include an outer peripheral coil conductor portion wound in a first direction and the first direction. An inner circumferential coil conductor portion wound in a reverse direction, wherein the outer circumferential coil conductor portion is located at a distance from the winding shaft in the radial direction in the radial direction as viewed from the winding axis direction. It is preferable that the number of turns of the outer coil conductor is larger than the number of turns of the inner coil conductor, which is farther than the conductor. In this configuration, a magnetic flux is generated around the inner peripheral coil conductor of the coil conductor, and a part of the magnetic flux (magnetic flux generated from the outer peripheral coil conductor) contributing to the magnetic field coupling with the coil antenna of the coupling partner is canceled. Therefore, with this configuration, variation in the coupling strength due to the relative positional relationship with the coil antenna of the coupling partner is suppressed.

(5) In any one of the above items (1) to (4), the coil conductor may include a first coil conductor portion having a short distance from the winding axis in a radial direction, and a first coil conductor portion extending from the winding axis in the radial direction. A distance between the coil conductors adjacent to each other is greater in the first coil conductor than in the second coil conductor. 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 (the first coil conductor) where the magnetic flux density tends to increase is high. The coil conductor is wound sparsely. Generally, 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 becomes stronger as it is closer to the winding axis (the center of the coil) in the radial direction, and becomes weaker as it is farther from the winding axis (the center of the coil). According to the above configuration, the coil is wound so that the distance between the adjacent coil conductors becomes closer toward the outer periphery from the winding axis in the radial direction, so that the magnetic flux density on the upper surface (or lower surface) of the coil antenna is reduced. The component in the winding axis direction becomes uniform. Therefore, variation in coupling strength due to the relative positional relationship with the coupling partner coil antenna is suppressed, and a coil antenna in which the coupling coefficient with the coupling partner coil antenna is stabilized in a wide range of relative positional relationship. realizable.

(6) In the above (5), it is preferable that a line width of the first coil conductor is larger than a line width of the second coil conductor. With this configuration, the DC resistance component of the entire coil antenna can be reduced. Further, 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 forming the coil antenna is narrower. 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 above configuration can further increase the number of turns of the coil conductor.

(7) In any one of the above (1) to (6), further comprising a second conductive member overlapping the coil conductor when viewed from the winding axis direction, wherein the coil conductor is configured to have the winding in a radial direction. A first coil conductor having a short distance from an axis; and a second coil conductor having a distance from the winding axis in the radial direction that is farther than the first coil conductor. It is preferable that the member overlaps with the first coil conductor and does not overlap with the second coil conductor when viewed from the winding axis direction. In this configuration, when viewed from the winding axis direction, the second conductive member overlaps the inner periphery (first coil conductor portion) of the coil conductor where the magnetic flux density tends to increase, and the outer periphery (the coil conductor) where the magnetic flux density tends to decrease. The second conductive member does not overlap the second coil conductor. Therefore, the formation of the magnetic field in the first coil conductor is partially prevented by the second conductive member, and the variation in the magnetic flux density formed by the coil conductor is suppressed. By making the magnetic flux density formed by the coil conductors uniform, variation in the 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), it is preferable that the first conductive member is a mesh-shaped 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), it is preferable that the second conductive member is a mesh-shaped 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 minimal portions of a radius of curvature in one turn.

(11) The power supply device of the present invention
A power supply device in a wireless power supply system that wirelessly supplies power from a power supply device to a power receiving device,
A power feeding coil antenna used for coupling with the power receiving device,
A power supply circuit connected to the power supply coil antenna,
With
The feeding coil antenna,
A coil conductor wound multiple times around a winding axis;
A first conductive member that at least partially overlaps a minimum portion of a radius of curvature in a circumferential direction of the coil conductor when viewed from the winding axis direction;
With
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.

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

(12) In the above (11), the power supply circuit may apply an alternating voltage in the HF band to the power supply 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 supply device to a power receiving device,
A power receiving coil antenna used for coupling with the power supply device,
A power receiving circuit connected to the power receiving coil antenna,
With
The power receiving coil antenna,
A coil conductor wound multiple times around a winding axis;
A first conductive member that at least partially overlaps a minimum portion of a radius of curvature in a circumferential direction of the coil conductor when viewed from the winding axis direction;
With
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.

  With this configuration, it is possible to realize a power supply 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 constituted by a capacitance component of the power reception circuit and an inductance component of the power reception coil antenna, and a resonance frequency of the resonance circuit may be a frequency in an HF band. .

(15) A wireless power supply system including the power supply device and the power receiving device of the present invention includes:
The power supply device,
A power feeding coil antenna used for coupling with a power receiving coil antenna provided in the power receiving device,
A power supply circuit connected to the power supply coil antenna,
Has,
The feeding coil antenna,
A coil conductor wound multiple times around a winding axis;
A first conductive member that at least partially overlaps a minimum portion of a radius of curvature in a circumferential direction of the coil conductor when viewed from the winding axis direction;
With
The first conductive member has a cutout portion that does not overlap with the coil conductor other than the minimum portion, as viewed from the winding axis direction,
The area of the formation area of the power feeding coil antenna is larger than the area of the formation area of the power receiving coil antenna.

  With this configuration, it is possible to realize a wireless power supply system including a power supply device including a power supply coil antenna having 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 arranged on a side opposite to the power receiving coil antenna 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 hindered by the first conductive member.

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

(18) The wireless power supply system including the power supply device and the power receiving device of the present invention includes:
The power receiving device,
A power receiving coil antenna used for coupling with a power feeding coil antenna provided in the power feeding device,
A power receiving circuit connected to the power receiving coil antenna,
Has,
The power receiving coil antenna,
A coil conductor wound multiple times around a winding axis;
A first conductive member that at least partially overlaps a minimum portion of a radius of curvature in a circumferential direction of the coil conductor when viewed from the winding axis direction;
With
The first conductive member has a cutout portion that does not overlap with the coil conductor other than the minimal portion, as viewed from the winding axis direction,
The area of the formation area of the power feeding coil antenna is larger than the area of the formation area of the power receiving coil antenna.

  With this configuration, it is possible to realize a wireless power supply system including a power receiving device including a power receiving coil antenna having 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 arranged on the opposite side of the coil conductor from the coil conductor. With this configuration, it is possible to prevent the magnetic flux passing through the opening of the coil conductor provided in the power receiving coil antenna from being hindered by the first conductive member.

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

  According to the present invention, a coil antenna having a small change in coupling strength due to a relative positional relationship with a coupling partner coil antenna can be realized with a simple structure. Further, a power supply 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 a 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 the 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 supply 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 a radius of curvature of the coil conductor 32 in the circumferential direction. 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 coil conductor portion MP and the outer coil conductor portion FP, and FIG. 7B is a diagram showing a first coil conductor portion CP1 and a second coil conductor portion CP2. FIG. 4 is a plan view of a coil conductor 33 showing the above. FIG. 8A is a plan view of a coil antenna 104 according to the fourth embodiment, and FIG. 8B is a plan view of a coil conductor 31 showing an inner coil conductor MP and an outer coil conductor FP. is there. FIG. 9 is a cross-sectional view illustrating a coupling relationship between the coil antenna 104 and the coil antenna 201 of the coupling partner. FIG. 10A is a plan view of a coil antenna 105 according to the fifth embodiment, and FIG. 10B is a plan view of a coil conductor 31 showing an inner coil conductor MP and an outer coil conductor FP. is there. FIG. 11 is a cross-sectional view illustrating the coupling relationship between the coil antenna 105 and the coil antenna 201 of the coupling partner. FIG. 12 is a plan view of the coil antenna 106 according to the sixth embodiment. FIG. 13A is a plan view of the coil conductor 36 showing the inner coil conductor portion MP and the outer coil conductor portion FP, and FIG. 13B is a diagram showing a first coil conductor portion CP1 and a second coil conductor portion CP2. FIG. 6 is a plan view of the coil conductor 36, which shows the above. FIG. 14 is a plan view of the coil antenna 107 according to the seventh embodiment. FIG. 15A is a plan view of a coil conductor 37 showing an inner coil conductor portion MP and an outer coil conductor portion FP, and FIG. 15B is a diagram showing a first coil conductor portion CP1 and a second coil conductor portion CP2. FIG. 4 is a plan view of a coil conductor 37 showing the above. FIG. 16A is a plan view of a coil antenna 108 according to the eighth embodiment, and FIG. 16B is a plan view of the coil antenna 108 showing a minimum portion PS of a 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, a plurality of embodiments for carrying out the present invention will be described with reference to the drawings and some specific examples. In the drawings, the same parts are denoted by the same reference numerals. Although the embodiments are shown separately for convenience in consideration of the explanation of the main points or the ease of understanding, it is possible to partially replace or combine the configurations shown in different embodiments. From the second embodiment onward, description of matters common to the first embodiment will be omitted, and only different points will be described. In particular, the same operation and effect of the same configuration will not be sequentially described for each embodiment.

  INDUSTRIAL APPLICABILITY The present invention is suitable for a system requiring 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 the mouse, the “coil antenna” of the present invention is provided on, for example, a mouse pad, and the power receiving coil antenna is provided on the mouse.

<< 1st 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 a radius of curvature of the coil conductor 31 in the circumferential direction. is there. FIG. 2 is a plan view of the coil conductor 31. In FIG. 1A, the base material 1 is not shown for easy understanding of the structure, and the first conductive members 11A, 11B, 11C, and 11D are provided with a texture pattern. Further, in FIG. 1B, illustration of the first conductive members 11A, 11B, 11C, 11D is omitted for easy understanding of the structure.

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

  The substrate 1 is a rectangular flat plate made of an insulating material. The coil conductor 31 is formed on the surface of the base material 1 or the like, and is a rectangular spiral conductor pattern of about four turns wound around the winding axis AX. The first end E1 and the second end E2 are Have. The substrate 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, 11D are rectangular flat plates. Part of the plurality of first conductive members 11A, 11B, 11C, 11D overlaps 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 the minimum portion PS of the radius of curvature in the circumferential direction of the coil conductor 31 when viewed from the Z-axis direction. In addition, the first conductive members 11A, 11B, 11C, and 11D have cutout portions C1, C2, C3, and C4 that do not overlap the coil conductor 31 other than the minimal portion PS when viewed from the Z-axis direction. The first conductive members 11A, 11B, 11C, 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 11A, 11B, 11C, and 11D have a shape that overlaps the plurality of the minimum portions PS and extends in the radial direction of the coil conductor 31 when 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 (see CD in FIG. 2) extending around the winding axis AX of the coil conductor, and the “radial direction” of the coil conductor in the present invention. "Means, for example, a direction perpendicular to the direction in which the coil conductor extends (see RD in FIG. 2). 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 of the coil conductor in the circumferential direction” in the present invention is a portion provided in the middle of the coil conductor wound around the winding axis AX when viewed from the Z-axis direction. In other words, for a portion where the radius of curvature is minimal when the coil conductor is pulled out from the inner periphery to the outer periphery, such as the lead portion XP shown in FIG. Tiny part of ". This is the same in the following embodiments. In the present invention, the “minimum portion of the radius of curvature of the coil conductor in the circumferential direction” includes the minimal portion where the differential coefficient is simply zero when the radius of curvature of the coil conductor viewed in the Z-axis direction is differentiated in the circumferential direction. This includes not only a structure in which a linearly extending portion and a bent portion are continuous as in the coil conductor 21 according to the present embodiment, but also a minimal portion of the coil conductor that continues to bend. 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 the difference is extremely small (relatively between any two points). The bent portion to be a portion is also included in the "minimum portion of the radius of curvature of the coil conductor in the circumferential direction" in the present invention.

  FIG. 3 is a cross-sectional view showing the 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 which is the feeding coil antenna (the area of the formation area of the coil conductor in FIG. 2) is equal to the formation area of the coupling antenna 201 which is the power receiving coil antenna. (Area of the formation region of the coil conductor). Further, as shown in FIG. 3, the first conductive members 11A and 11B and the like are arranged on the opposite side of the coil antenna 31 with respect to the coil antenna 201 in the Z-axis direction. In other words, the first conductive members 11A, 11B and the like are arranged on the opposite side of the coil conductor 31 from the coil antenna 201 of the coupling partner.

  In general, magnetic flux is likely to be strong inside a portion having 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 tends to be relatively high as compared with 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 the minimal part PS of the curvature radius of 31. In addition, the first conductive members 11A, 11B, 11C, and 11D have cutout portions C1, C2, C3, and C4 that do not overlap the coil conductor 31 other than the minimal portion PS when viewed from the Z-axis direction. Therefore, the formation of the magnetic field in the minimal portion PS is partially prevented by the first conductive members 11A, 11B, 11C, and 11D, and variation in the magnetic flux density formed by the coil conductor 31 is suppressed. By making the magnetic flux density formed by the coil conductors uniform, variation in the coupling strength due to the relative positional relationship with the coil antenna of the coupling partner is suppressed. Therefore, with a simple structure, it is possible to realize a coil antenna in which the coupling coefficient with the coupling partner coil antenna is stabilized in a wide range of relative positional relationship.

  In the present embodiment, each of the first conductive members 11A, 11B, 11C, and 11D overlaps the plurality of minimum parts PS and extends in the radial direction of the coil conductor 31 when 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 overlap with each other when viewed from the Z-axis direction. Therefore, the above-described functions and effects can be obtained only by providing a small number of first conductive members 11A, 11B, 11C, and 11D with a simple shape.

  In the present 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 of the coupling partner, the position freedom of the coil antenna 201 on the plane with respect to the coil antenna 101 is large. The degree can be increased.

  In the present embodiment, the first conductive members 11A, 11B, 11C, and 11D are arranged on the opposite side of the coil conductor 31 from the coil antenna 201 of the coupling partner. The first conductive members 11A, 11B, 11C, 11D may be arranged on the side of the coil antenna 201 of the coupling partner with respect to the coil conductor 31, but are arranged on the side opposite to the coil antenna 201 of the coupling partner with respect to the coil conductor 31. It is desirable to be. When the first conductive members 11A, 11B, 11C, and 11D 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 prevented. Could be too much. However, since the first conductive members 11A, 11B, 11C, and 11D are arranged on the opposite side to the coil antenna 201 of the coupling partner with respect to the coil conductor 31, the gap between the coil conductor 31 and the coil antenna 201 of the coupling partner is provided. As compared with the case where the first conductive members 11A, 11B, 11C, and 11D are arranged, the coil antenna 101 is more easily magnetically coupled to the coil antenna 201 of the coupling partner. Further, with this configuration, it is possible to suppress the occurrence of parasitic capacitance between the first conductive members 11A, 11B, 11C, and 11D and the coupling partner coil antenna 201.

  In the present embodiment, the configuration in which the first conductive members 11A, 11B, 11C, and 11D respectively overlap the four minimum portions PS when viewed from the Z-axis direction has been described. However, the configuration is not limited thereto. . In order to achieve the above-described functions and effects of the present invention, the first conductive member only needs to overlap one or more minimal parts PS when viewed from the Z-axis direction.

  Further, in the present embodiment, an example of the coil antenna including the four first conductive members 11A, 11B, 11C, and 11D, which 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 appropriately changed as long as the functions and effects of the present invention are achieved, as will be described in detail later. Also, the shape of the first conductive member is not limited to a rectangular flat plate, and can be appropriately changed within a range in which the operation and effect of the present invention can be 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. In addition, 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.

  Further, 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 operation is performed when the coil antenna 101 is a power receiving coil antenna. This is the same for the coil antennas according to the following embodiments. Note that, even when the coil antenna 101 is a power receiving coil antenna, the first conductive members 11A, 11B, 11C, and 11D are on the opposite side of the coil conductor 31 from the coil antenna 201 (feeding coil antenna) of the coupling partner. 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 supply device 301 including the coil antenna 101 according to the first embodiment.

  The power supply device 301 includes a resin cover 2, a coil antenna 101, a circuit board 4, a power supply circuit (not shown), and the like. The power supply 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, the coil antenna 101, the circuit board 4, the power supply circuit, and the like are housed inside the resin cover 2. The circuit board 4 is a board in which the ground conductor 5 is formed, 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 or the like (not shown). The power supply circuit is, for example, a power supply 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 supply device of a wireless power supply system including a power supply coil antenna having a small change in coupling strength due to a relative positional relationship with a coupling partner coil antenna.

  In the power supply device shown in FIG. 4, the first conductive members 11A and 11B and the like are arranged between the coil conductor 31 and the circuit board 4. With this configuration, a magnetic shielding effect on the back surface side of the first conductive members 11A and 11B (lower surface side of the first conductive members 11A and 11B in FIG. 4) is obtained, and the circuit board 4 has a wiring pattern and a coil antenna. Unnecessary bonding with the carbon is suppressed. Further, 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 the present embodiment, an example is shown in which the coil antenna 101 is provided on a mouse pad or the like as a power feeding coil antenna, and the coil antenna of a coupling partner is provided on a mouse as a power receiving coil antenna. However, the present invention is limited to this configuration. Not something. As will be described in detail later, the coil antenna of the present invention is a coil antenna used for coupling a power supply device and a power receiving device that constitute a wireless power supply system, and is provided in one or both of the power feeding device and the power receiving device. Can be

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

<< 2nd Embodiment >>
In the second embodiment, an example in which the structure of the coil conductor is different from that of the coil antenna 101 according to the first embodiment will be described.

  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 a radius of curvature of the coil conductor 32 in the circumferential direction. is there. In FIG. 5A, the illustration of the substrate 1 is omitted and the first conductive members 12A and 12B are provided with a texture pattern for easy understanding of the structure. Further, in FIG. 5B, illustration of the first conductive members 12A and 12B is omitted for easy understanding of the structure.

  The coil antenna 102 according to the present embodiment differs from the coil antenna 101 according to the first embodiment in that the coil antenna 102 includes the coil conductor 32. Further, the coil antenna 102 according to the present embodiment is different from the coil antenna 101 in that the coil antenna 102 includes the first conductive members 12A and 12B. 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 substrate 1 or the like, and has an elliptical spiral shape of about four turns wound around the winding axis AX. It is a conductor pattern and has a first end E1 and a second end E2. As described above, the “minimum portion of the radius of curvature” of the elliptical coil conductor is, when viewed from the Z-axis direction, a semicircular portion at both ends (both ends in the Y-axis direction of the coil conductor 32 in FIG. 5B). 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 the minimum portion PS of the radius of curvature in the circumferential direction of the coil conductor 32 when viewed from the Z-axis direction. Further, the first conductive members 12A and 12B have cutout portions C1 and C2 that do not overlap with the coil conductor 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 operation and effect as the coil antenna 101.

<< 3rd Embodiment >>
In the third embodiment, an example in which the structure of the coil conductor is different from the coil antenna according to each embodiment 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 coil conductor portion MP and the outer coil conductor portion FP, and FIG. 7B is a diagram showing a first coil conductor portion CP1 and a second coil conductor portion CP2. FIG. 4 is a plan view of a coil conductor 33 showing the above. In FIG. 6, in order to make the structure easy to understand, the illustration of the base material 1 is omitted, and a texture pattern is given to the first conductive members 11A, 11B, 11C, 11D. In FIG. 7 (A), the inner coil conductor MP is indicated by a broken line, and the outer coil conductor FP is indicated by a solid line for easy understanding of the structure. Further, in FIG. 7B, for easy 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 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 103 includes a coil conductor 33, and the other configuration is substantially the same as the coil antenna 101.

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

  That is, the coil conductor 33 according to the present embodiment includes the outer coil conductor FP and the inner coil conductor MP located on the inner periphery of the outer coil conductor FP. The outer coil conductor FP and the inner coil conductor MP are wound in opposite directions, and the number of turns of the outer coil conductor FP is greater than the number of turns of the inner coil conductor MP.

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

  As shown in FIG. 7B, the coil conductor 33 according to the present embodiment includes a first coil conductor portion CP <b> 1 whose distance from the winding axis AX in the radial direction is short, and a coil conductor 33 in the radial direction. And a second coil conductor part CP2 whose distance is longer than the first coil conductor part. The distance R2 from the winding axis AX in the radial direction of the second coil conductor part CP2 is longer than the distance R1 from the winding axis AX in the radial direction of the first coil conductor part CP1 (R2> R1). In the present embodiment, the first coil conductor portion CP1 is located at the innermost periphery of the coil conductor 33 and is a conductor of about one turn wound around the winding axis AX. Further, in the present embodiment, the second coil conductor portion CP2 is a conductor of about two turns which is located on the outer periphery of the first coil conductor portion CP1 and is wound around the winding axis AX.

  The gap G1 between the coil conductors 33 adjacent to each other in the first coil conductor part CP1 is larger than the gap G2 between the coil conductors 33 adjacent to each other in the second coil conductor part CP2 (G1> G2). That is, in the present embodiment, when viewed from the Z-axis direction, the coil conductor 33 is sparsely 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 need not necessarily be adjacent to each other in the first coil conductor portion CP1. Further, the coil conductors 33 need not necessarily be 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 an arbitrary number of times around the winding axis AX. The first coil conductor portion CP1 may not be the conductor located on the innermost periphery of the coil conductor 33, and the second coil conductor portion CP2 may be a conductor located relatively on the outer periphery than the first coil conductor portion CP1. Good. The coil conductor may include another conductor part other than the first coil conductor part CP1 and the second coil conductor part CP2.

  According to the coil antenna 103 according to the present embodiment, the following effects are obtained in addition to the effects described in the first embodiment.

  In the present embodiment, when viewed from the Z-axis direction, the inner periphery of the coil conductor 33 (the inner periphery coil conductor portion MP) and the outer periphery of the coil conductor 33 (the outer periphery coil conductor portion FP) are wound in opposite directions, and The inner circumference of the coil conductor 33 has a smaller number of turns than the outer circumference of the coil conductor 33. For this reason, a magnetic flux is generated from the inner peripheral coil conductor portion MP of the coil conductor 33 in a direction opposite to a magnetic flux contributing to magnetic field coupling with the coil antenna of the coupling partner (a magnetic flux generated from the outer peripheral coil conductor portion FP). Part of the magnetic flux that contributes to the magnetic field coupling with the other coil antenna is canceled. That is, with this configuration, the magnetic flux density at the inner periphery of the coil conductor, where the magnetic flux density tends to be high, is suppressed, and the magnetic flux density formed by the coil conductor becomes uniform, depending on the relative positional relationship with the coil antenna of the coupling partner. Variation in bonding strength is suppressed.

  Further, in the present embodiment, when viewed from the Z-axis direction, the coil conductor 33 is sparsely wound on the inner periphery (first coil conductor portion CP1) where the magnetic flux density tends to be high, and the outer periphery (the first coil conductor portion) where the magnetic flux density tends to be low. The two-coil conductor portion CP2) has a structure in which the coil conductor 33 is densely wound. In other words, a portion where the interval between the coil conductors 33 is close is located closer to the outer periphery from the winding axis AX in the radial direction, and a sparse portion is located closer to the inner periphery from the winding shaft AX in the radial direction. . Generally, 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 direction of the winding axis is stronger as it is closer to the winding axis (center of the coil) and weaker as it is farther from the winding axis (center of the coil). However, in the coil antenna 103, the coil conductors L1 and L2 are wound such that the closer to the outer periphery from the winding axis AX in the radial direction, the closer the gap between the coil conductors L1 and L2 is. The component in the winding axis direction of the magnetic flux density becomes uniform. Therefore, with this configuration, variation in coupling strength due to the relative positional relationship with the coupling partner coil antenna is suppressed, and the coupling coefficient with the coupling partner coil antenna is stabilized in a wide range of relative positional relationship. Coil antenna can be realized.

  In the present embodiment, an example is shown in which the outer coil conductor portion FP is a conductor portion of about two turns and the inner coil conductor portion MP is a conductor portion of about two turns, but is not limited to this configuration. is not. The number of turns of the outer coil conductor FP and the number of turns of the inner coil conductor MP can be appropriately changed within a range in which the functions and effects of the present invention can be obtained.

  Further, in the present embodiment, an example has been described in which the first coil conductor portion CP1 is a conductor portion of about one turn, and the second coil conductor portion CP2 is a conductor portion of about two turns. However, the present invention is limited to this configuration. Not something. 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 appropriately changed within a range in which the functions and effects of the present invention can be obtained.

<< 4th Embodiment >>
In the fourth embodiment, a coil antenna further including a second conductive member will be described.

  FIG. 8A is a plan view of a coil antenna 104 according to the fourth embodiment, and FIG. 8B is a plan view of a coil conductor 31 showing an inner coil conductor MP and an outer coil conductor FP. is there. FIG. 9 is a cross-sectional view illustrating a coupling relationship between the coil antenna 104 and the coil antenna 201 of the coupling partner. In FIG. 8A, for simplification of the structure, the illustration of the base material 1 is omitted, and a texture pattern is applied to the first conductive members 11A, 11B, 11C, 11D and the second conductive member 24. Has been granted. Further, in FIG. 8B, for easy understanding of the structure, 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. 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 the coil antenna 104 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 coil conductor MP and an outer coil conductor FP. In the present embodiment, the outer peripheral coil conductor portion FP is the outermost periphery of the coil conductor 31 and is a conductor of about two turns wound around the winding axis AX. Further, in the present embodiment, the inner coil conductor MP is a conductor of about two turns which is located on the inner periphery of the outer coil conductor FP and is wound around the winding axis AX.

  The second conductive member 24 is a rectangular flat plate. 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 MP when viewed from the Z-axis direction. Further, the second conductive member 24 does not overlap with the outer peripheral coil conductor 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 of the coil antenna 31 with respect to the coil antenna 201 with respect to the Z-axis direction. In other words, the second conductive member 24 is arranged on the opposite side to the coil antenna 201 of 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 in the Z-axis direction.

  In the present embodiment, when viewed from the Z-axis direction, the second conductive member 24 overlaps the inner periphery (inner coil conductor portion MP) of the coil conductor 31 or the coil opening CM where the magnetic flux density tends to be higher, and the magnetic flux density is lower. The second conductive member 24 does not overlap the outer periphery (outer peripheral coil conductor portion FP) of the coil conductor 31 that is likely to be formed. Therefore, the formation of a magnetic field in the inner periphery of the coil conductor 31 and the coil opening CM is partially prevented by the second conductive member 24, and the variation in the magnetic flux density formed by the coil conductor 31 is suppressed. By making the magnetic flux density formed by the coil conductors uniform, variation in the coupling strength due to the relative positional relationship with the coil antenna 201 of the coupling partner is further suppressed.

  It is preferable that the second conductive member 24 is disposed on the opposite side of the coil conductor 201 from the coil conductor 31 similarly to the first conductive members 11A, 11B, 11C, and 11D. This configuration makes it easier for the coil antenna 104 to perform magnetic field coupling with the coupling partner coil antenna 201 than when the second conductive member 24 is disposed between the coil conductor 31 and the coupling partner coil antenna 201.

  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 in the Z-axis direction has been described, but the present invention is not limited to this configuration. Not something. The second conductive member 24 may be arranged on the same plane as the first conductive member in the Z-axis direction, and is more distant from the coil conductor 31 than the first conductive member in the Z-axis direction. It may be arranged at a position.

<< 5th Embodiment >>
In the fifth embodiment, a coil antenna including first conductive members having different shapes will be described.

  FIG. 10A is a plan view of a coil antenna 105 according to the fifth embodiment, and FIG. 10B is a plan view of a coil conductor 31 showing an inner coil conductor MP and an outer coil conductor FP. is there. FIG. 11 is a cross-sectional view illustrating the coupling relationship between the coil antenna 105 and the coil antenna 201 of the coupling partner. In FIG. 10A, the base material 1 is not shown and the first conductive member 15 is provided with a texture pattern for easy understanding of the structure. In FIG. 10B, the inner coil conductor MP is shown by a broken line, and the outer coil conductor FP is shown by a solid line for easy understanding of the structure. In FIG. 11, the coil antenna 105 is a power feeding coil antenna, and the coupling partner coil antenna 201 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 coil conductor MP and an outer coil conductor FP. In the present embodiment, the outer peripheral coil conductor portion FP is the outermost periphery of the coil conductor 31 and is a conductor of about two turns wound around the winding axis AX. Further, in the present embodiment, the inner coil conductor MP is a conductor of about two turns which is located on the inner periphery of the outer coil conductor FP and is wound around the winding axis AX.

  The first conductive member 15 includes a first conductive member (first conductive members 11A, 11B, 11C, and 11D in FIG. 8A) and a second conductive member according to the fourth embodiment when viewed from the Z-axis direction. 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 minimum 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 the coil opening CM and the inner peripheral coil conductor portion MP but does not overlap the outer peripheral coil conductor portion 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 periphery (the inner peripheral coil conductor portion MP) of the coil conductor 31 or the coil opening CM where the magnetic flux density tends to be high, and the magnetic flux density is low. The first conductive member 15 does not overlap with the outer periphery (outer peripheral coil conductor portion FP) of the coil conductor 31 that is likely to be formed. Therefore, the formation of a magnetic field in the inner periphery of the coil conductor 31 and the coil opening CM is partially prevented by the first conductive member 15, and the variation in the magnetic flux density formed by the coil conductor 31 is suppressed. By making the magnetic flux density formed by the coil conductor uniform, variation in the 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 provided with an axially symmetric coil conductor will be described.

  FIG. 12 is a plan view of the coil antenna 106 according to the sixth embodiment. FIG. 13A is a plan view of the coil conductor 36 showing the inner coil conductor portion MP and the outer coil conductor portion FP, and FIG. 13B is a diagram showing a first coil conductor portion CP1 and a second coil conductor portion CP2. FIG. 6 is a plan view of the coil conductor 36, which shows the above. In FIG. 12, for simplification of the structure, the illustration of the base material 1 is omitted, and a texture pattern is given to the first conductive members 11A, 11B, 11C, 11D. In FIG. 13A, the inner coil conductor MP is indicated by a broken line, and the outer coil conductor FP is indicated by a solid line. In FIG. 13 (B), 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 for easy understanding of the structure.

  The coil antenna 106 according to the present embodiment differs from the coil antenna 101 according to the first embodiment in that the coil antenna 106 includes an axially symmetric coil conductor 36, 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 (symmetric axis) SA passing between the first end E1 and the second end E2 when viewed from the Z-axis direction. The coil conductor 36 has intersections CR1 and CR2 that intersect with each other so that the inner and outer arrangements of the adjacent coil conductors are switched. These intersections CR1 and CR2 intersect via an insulating layer so that adjacent coil conductors do not short-circuit.

  As shown in FIG. 13A, the coil conductor 36 according to the present embodiment includes two outer coil conductors FP and an inner coil conductor 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 wound counterclockwise (a direction opposite to the first direction) when viewed from the Z-axis direction.

  Further, as shown in FIG. 13 (B), the coil conductor 36 according to the present embodiment includes a first coil conductor portion CP1 whose distance from the winding axis AX in the radial direction is short, and a coil conductor 36 in the radial direction. And a second coil conductor part CP2 whose distance is longer than the first coil conductor part. 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 two turns wound around the winding axis AX. Further, in the present embodiment, the second coil conductor CP2 is two conductors of about one turn wound around the winding axis AX, which are located on the outer periphery of the first coil conductor CP1. When viewed from the Z-axis direction, the coil conductor 36 is sparsely wound in the first coil conductor portion CP1, and the coil conductor 36 is densely wound in the second coil conductor portion CP2.

  Generally, in a coil conductor wound in line symmetry, there is a problem that the influence of the line capacitance between adjacent coil conductors increases due to connection with a power supply circuit (or a 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 that sparsely winds the coil conductor and the outer peripheral portion that is densely wound. On the other hand, in the present embodiment, since the inner peripheral coil conductor portion MP wound in the opposite direction to the outer peripheral coil conductor portion FP is provided, the magnetic flux density of the inner peripheral portion of the coil conductor where the magnetic flux density tends to be high is reduced It is suppressed (see the second embodiment). That is, according to this configuration, the coil conductor 36 is not densely wound around the second coil conductor portion CP2 (the gap G2 between the coil conductors 36 can be reduced as compared with the case where the inner peripheral coil conductor portion MP is not provided). Rather, it is possible to realize a coil antenna in which variation in coupling strength due to a relative positional relationship with a coil antenna of a coupling partner is suppressed.

  In the present embodiment, since the coil conductor 36 is line-symmetric with respect to an axis (symmetric 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 the coil conductors adjacent to each other is targeted, and the uniformity of the magnetic field radiation of the coil antenna is ensured. Further, when the power supply circuit (or power receiving circuit) connected to the coil antenna 106 is a balanced circuit, the balance seen from the power supply circuit (or power receiving circuit) can be maintained.

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

  FIG. 14 is a plan view of the coil antenna 107 according to the seventh embodiment. FIG. 15A is a plan view of a coil conductor 37 showing an inner coil conductor portion MP and an outer coil conductor portion FP, and FIG. 15B is a diagram showing a first coil conductor portion CP1 and a second coil conductor portion CP2. FIG. 4 is a plan view of a coil conductor 37 showing the above. In FIG. 14, for simplification of the structure, the illustration of the base material 1 is omitted, and a texture pattern is given to the first conductive members 11A, 11B, 11C, 11D. In FIG. 15A, the inner coil conductor MP is indicated by a broken line, and the outer coil conductor FP is indicated by a solid line. In FIG. 15B, 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 for easy understanding of the structure.

  The coil antenna 107 according to the sixth embodiment differs 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 this, the other configuration is substantially the same as that of the coil antenna 106.

  As shown in FIG. 14 and the like, in the coil conductor 37 according to the present 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 large (because 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 portion CP1 having a large line width is different from the gap G2 between the coil conductors 37 adjacent to each other in another portion (the second coil conductor portion CP2). (G1> G2). Therefore, even if the line width of the inner peripheral portion (first coil conductor portion CP1) around which the coil conductor 37 is sparsely wound is made larger than the line width of the other portions, the line capacitance between adjacent coil conductors is obtained. Increase is small.

  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 forming the coil antenna is narrower. Therefore, with the above configuration, the inductance value of the entire coil antenna is lower than in the case where the entire line width of the coil conductor 37 is the same. Therefore, if the coil antenna has the same inductance value, the above configuration can further increase the number of turns of the outer peripheral portion or the like where the coil conductor is densely wound.

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

  FIG. 16A is a plan view of a coil antenna 108 according to the eighth embodiment, and FIG. 16B is a plan view of the coil antenna 108 showing a minimum portion PS of a radius of curvature in the circumferential direction of the coil conductor 31. is there. In FIG. 16 (A), for simplicity of the structure, the illustration of the base material 1 is omitted, and a texture pattern is applied to the first conductive members 11A, 11B, 11C, 11D, and the magnetic member 48A is provided. , 48B, 48C, and 48D are cross hatched. Further, in FIG. 16B, illustration of the first conductive members 11A, 11B, 11C, and 11D is omitted for easy understanding of the structure.

  The coil antenna 108 according to the present embodiment differs from the coil antenna 101 according to the first embodiment in that the coil antenna 108 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 cutouts C1, C2, C3, and C4 shown in FIG. 16B when viewed from the Z-axis direction. That is, the magnetic members 48A, 48B, 48C, 48D are arranged in the cutouts C1, C2, C3, C4, respectively. The magnetic members 48A, 48B, 48C, and 48D are, for example, sintered magnetic ferrite plates, and a resin sheet or the like in which a magnetic powder such as a ferrite powder is dispersed in a resin such as an epoxy resin is used as the base material 1. It may be affixed.

  Generally, the magnetic flux density of the other portions of the coil conductor tends to be relatively lower than that of the minimal portion PS of the radius of curvature of the coil conductor. In the present embodiment, since the magnetic members 48A, 48B, 48C, and 48D are arranged in other portions (the punched portions C1, C2, C3, and C4) where the magnetic flux density tends to be relatively low, the magnetic conductors are not connected to the coil conductor. Variations in magnetic flux density due to the positional relationship are suppressed. Further, with this configuration, the inductance value of the coil antenna is increased as compared with the case where the magnetic member is not provided, so that the coil antenna itself can be downsized.

  The magnetic member is preferably arranged on the opposite side of the coil conductor 31 from the coil antenna of the coupling partner. This makes it easier for the coil antenna of the present invention to perform magnetic field coupling with the coupling partner coil antenna. Further, the shape, the number, and the like of the magnetic members are not limited to those described in the present embodiment. The shape, the number, and the like of the magnetic members can be appropriately changed within a range in which the operation and effect of the present invention can be achieved. That is, the magnetic member may be, for example, rectangular, circular, or the like, and the coil antenna may have a single magnetic member.

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

  The “feeding device” in the present invention is a device including the coil antenna and a feeding circuit (to be described in detail later) and the like, and is, for example, the mouse pad and the like corresponding to a wireless power supply system such as a magnetic resonance power supply system. The “power receiving device” in the present invention is a device including the coil antenna and a power receiving circuit (described in detail later) and the like. For example, a power receiving side device (wireless mouse, wireless mouse, etc.) compatible with a wireless power supply system such as a magnetic resonance power supply system A charger for wirelessly supplying a mobile phone terminal, a so-called smartphone, tablet terminal, notebook PC, PDA, wearable terminal, camera, video, game machine, toy, and the like.

  The magnetic resonance power supply system is used in the HF band, especially at frequencies around 6.78 MHz. Further, the magnetic field type wireless power supply system supplies power by coupling with a power supply partner by magnetic field coupling.

  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 supply device 301 and a power reception device 401, and wirelessly supplies power from the power supply device 301 to the power reception device 401.

  The power supply device 301 includes a power supply circuit 310, a power supply coil antenna Lt connected to the power supply circuit 310, and a resonance capacitor Ct connected in series to the power supply 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 form a resonance circuit 320.

  The power supply circuit 310 includes an inverter circuit 311 that converts a 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, Q2, capacitor C11, diode D1, and drive circuit 312. The drive circuit 312 alternately turns on / off the switching elements Q1 and Q2 at the HF band operating frequency (for example, 6.78 MHz). The resonance frequency of the resonance circuit 320 is the operating frequency or a frequency in the vicinity thereof. Thus, the power supply circuit 310 applies an alternating voltage in the HF band to the power supply 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 with the power supply 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 included in 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, similarly to the structure shown in the first embodiment, the area of the formation area of the power feeding coil antenna Lt is larger than the area of the formation area 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 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 resonance circuit 420 resonates at the operating frequency in the HF band or 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 power 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. The "ordinary coil antenna" is one in which the coil conductor has a simple loop or spiral shape.

  The power feeding coil antenna may be a normal coil antenna, and the power receiving coil antenna may be the coil antenna 101 described 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 structure, the power feeding coil antenna and the power receiving coil antenna are mainly magnetically coupled, and power is mainly transmitted through the magnetic field.

  As described above, 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, a power supply device, a power receiving device, and a wireless power supply system including a coil antenna having a small change in coupling strength due to a relative positional relationship with a partner coil antenna can be realized.

  In the present embodiment, an example has been described in which the 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. However, a resonance capacitor is connected in parallel to the power reception coil antenna Lr. May be connected.

<< Other embodiments >>
In each of the embodiments described above, the first conductive member and the second conductive member are examples of flat plates made of metal, graphite, or the like. However, the present invention is not limited to this configuration. The first conductive member and the second conductive member may be a conductor pattern of Cu or the like 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 a circuit board, a ground conductor, a shield case, a battery pack, or the like. When a conductor formed on a circuit board, a ground conductor, a shield case, a 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 may be used. Need not be separately formed, and the manufacturing is easy and the cost can be reduced.

  Note that the first conductive member may be a mesh-shaped conductor. By making the first conductive member a mesh-shaped conductor, deterioration of antenna characteristics due to parasitic capacitance generated between the first conductive member and the coil conductor is suppressed. This is the same for the second conductive member.

  In each of the embodiments described above, the example in which the base material 1 is a rectangular flat plate is shown, but the present invention is not limited to this configuration. The planar shape of the substrate 1 can be changed as appropriate, such as a circle, an ellipse, a square, and a polygon. In addition, 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 four turns formed on the surface of the base material 1 has been described, but the present invention is not limited to this configuration. The outer shape of the coil conductor 31 can be appropriately changed to a circle, an ellipse, a polygon, an L-shape, a T-shape or the like when viewed from the Z-axis direction. Further, the coil conductor 31 may be formed on the back surface or inside of the base material 1. Further, the coil conductor 31 may have a configuration in which a base material on which a spiral conductor pattern is formed is laminated to form a helical shape. Further, the coil conductor 31 may be a winding coil. That is, the substrate is not essential in the coil antenna of the present invention. In addition, the number of turns of the coil conductor 31 can be appropriately changed within a range in which the operation and effects of the present invention are achieved.

  Finally, the description of the above embodiments is illustrative in all respects and is not restrictive. Modifications and changes can be made by those skilled in the art as appropriate. The scope of the present invention is defined by the terms of the claims, rather than the embodiments described above. Further, the scope of the present invention includes modifications from the embodiments within the scope equivalent to the scope of the claims.

AX: winding shafts 31, 32, 33, 36, 37 coil conductor E1 first end E2 of coil conductor CM second end CM of coil conductor Coil openings C1, C2, C3, C4 cutout CP1 ... First coil conductor portion CP2. Second coil conductor portion FP... Outer peripheral coil conductor portion MP... Inner peripheral coil conductor portions CR1 and CR2... Intersections G1 and G2. , The distance Lr from the winding axis in the radial direction, the power receiving coil antenna Lt, the power feeding coil antenna C11, the capacitors C21, C22, the smoothing capacitor Ct, and the resonance capacitor D1. Diodes Q1, Q2 Switching element Ro Load Vi Visible 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 Rectifying smoothing circuit 412 Rectifying circuit 413 Voltage regulator circuit 420 Resonant circuit 501: wireless power supply system

Claims (19)

A coil antenna used for a wireless power supply system,
A coil conductor wound multiple times around a winding axis;
A first conductive member that at least partially overlaps a plurality of minimum portions of a radius of curvature in a circumferential direction of the coil conductor when viewed from the winding axis direction;
With
The first conductive member has a rectangular shape in a planar shape, and has a longitudinal direction extending in a radial direction of the coil conductor,
A coil antenna, wherein the first conductive member has a cutout portion that does not overlap with the coil conductor other than the plurality of minimum portions when viewed from the winding axis direction. 2. The coil antenna according to claim 1, wherein the coil conductor is line-symmetric with respect to an axis passing between the two end portions and intersecting with the winding axis, as viewed from the winding axis direction. 3. The coil conductor includes an outer coil conductor portion wound in a first direction and an inner coil conductor portion wound in a direction opposite to the first direction, as viewed from the winding axis direction. And
The outer peripheral coil conductor portion, when viewed from the winding axis direction, the distance from the winding axis in the radial direction is farther than the inner peripheral coil conductor portion,
The number of turns of the outer peripheral coil conductor portion is larger than the number of turns of the inner peripheral coil conductor portion, the coil antenna according to claim 1 or 2. The coil conductor has a first coil conductor portion that is closer to the winding axis in the radial direction, and a second coil conductor that has a longer distance from the winding axis in the radial direction than the first coil conductor portion. And a part,
Together gap adjacent said coil conductors, the second is larger in the first coil conductor portion than the coil conductor portion, the coil antenna according to any one of claims 1 to 3. The coil antenna according to claim 4 , wherein a line width of the first coil conductor is larger than a line width of the second coil conductor. It said first conductive member is a conductive meshed, the coil antenna according to any one of claims 1 to 5. A second conductive member that at least partially overlaps the coil conductor when viewed from the winding axis direction,
The coil conductor has a first coil conductor portion that is closer to the winding axis in the radial direction, and a second coil conductor that has a longer distance from the winding axis in the radial direction than the first coil conductor portion. And a part,
Said second conductive member, as viewed from the winding axis direction, the first overlapping the coil conductor section, and does not overlap the second coil conductor portion, the coil according to any one of claims 1 to 6 antenna. The coil antenna according to claim 7 , wherein the second conductive member is a mesh-shaped conductor. The coil antenna according to any one of claims 1 to 8 , wherein the coil conductor has a rectangular spiral shape having four minimal portions of a radius of curvature in one turn. A power supply device in a wireless power supply system that wirelessly supplies power from a power supply device to a power receiving device,
A power feeding coil antenna used for coupling with the power receiving device,
A power supply circuit connected to the power supply coil antenna,
With
The feeding coil antenna,
A coil conductor wound multiple times around a winding axis;
A first conductive member that at least partially overlaps a plurality of minimum portions of a radius of curvature in a circumferential direction of the coil conductor when viewed from the winding axis direction;
With
The first conductive member has a rectangular shape in a planar shape, and has a longitudinal direction extending in a radial direction of the coil conductor,
The power supply device, wherein the first conductive member has a cutout portion that does not overlap the coil conductor other than the plurality of minimum portions when viewed from the winding axis direction. The power supply device according to claim 10 , wherein the power supply circuit applies an alternating voltage in an HF band to the power supply coil antenna. A power receiving device in a wireless power supply system that wirelessly supplies power from a power supply device to a power receiving device,
A power receiving coil antenna used for coupling with the power supply device,
A power receiving circuit connected to the power receiving coil antenna,
With
The power receiving coil antenna,
A coil conductor wound multiple times around a winding axis;
A first conductive member that at least partially overlaps a plurality of minimum portions of a radius of curvature in a circumferential direction of the coil conductor when viewed from the winding axis direction;
With
The first conductive member has a rectangular shape in a planar shape, and has a longitudinal direction extending in a radial direction of the coil conductor,
The power receiving device, wherein the first conductive member has a cutout portion that does not overlap the coil conductor other than the plurality of minimum portions when viewed from the winding axis direction. A resonance circuit is formed by a capacitance component of the power receiving circuit and an inductance component of the power receiving coil antenna,
The power receiving device according to claim 12 , wherein a resonance frequency of the resonance circuit is a frequency in an HF band. In a wireless power supply system including a power supply device and a power reception device,
The power supply device,
A power feeding coil antenna used for coupling with a power receiving coil antenna provided in the power receiving device,
A power supply circuit connected to the power supply coil antenna,
Has,
The feeding coil antenna,
A coil conductor wound multiple times around a winding axis;
A first conductive member that at least partially overlaps a plurality of minimum portions of a radius of curvature in a circumferential direction of the coil conductor, as viewed from the winding axis direction;
With
The first conductive member has a rectangular shape in a planar shape, and has a longitudinal direction extending in a radial direction of the coil conductor,
The first conductive member has a cutout portion that does not overlap with the coil conductor other than the plurality of minimal portions, as viewed from the winding axis direction,
The wireless power supply system, wherein an area of the formation area of the power feeding coil antenna is larger than an area of the formation area of the power receiving coil antenna. The wireless power supply system according to claim 14 , wherein the first conductive member is arranged on a side opposite to the power receiving coil antenna with respect to the coil conductor. The power supply circuit applies an alternating voltage of the HF band in the feeding coil antenna, wireless power supply system according to claim 14 or 15. In a wireless power supply system including a power supply device and a power reception device,
The power receiving device,
A power receiving coil antenna used for coupling with a power feeding coil antenna provided in the power feeding device,
A power receiving circuit connected to the power receiving coil antenna,
Has,
The power receiving coil antenna,
A coil conductor wound multiple times around a winding axis;
A first conductive member that at least partially overlaps a plurality of minimum portions of a radius of curvature in a circumferential direction of the coil conductor when viewed from the winding axis direction;
With
The first conductive member has a rectangular shape in a planar shape, and has a longitudinal direction extending in a radial direction of the coil conductor,
The first conductive member has a cutout portion that does not overlap with the coil conductor other than the plurality of minimum portions, as viewed from the winding axis direction,
The wireless power supply system, wherein an area of the formation area of the power feeding coil antenna is larger than an area of the formation area of the power receiving coil antenna. The wireless power supply system according to claim 17 , 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 formed by a capacitance component of the power receiving circuit and an inductance component of the power receiving coil antenna,
Resonance frequency of the resonant circuit is the frequency of the HF band, the wireless power supply system according to claim 17 or 18.

Images