Wireless power supply sheet, wireless power supply device, and wireless power supply system

Abstract

[Problem] To provide a two-dimensional wireless power supply sheet that is less affected by water or the like and a wireless power supply system. [Solution] According to an embodiment of the present invention, a two-dimensional wireless power supply sheet is provided. The two-dimensional wireless power supply sheet comprises a dielectric layer, a first conductive layer, and a second conductive layer. The dielectric layer is formed by being sandwiched between the first conductive layer and the second conductive layer, and thereby guides electromagnetic waves in one predetermined direction. The first conductive layer includes a conductor having a first shape. The first shape shortens the wavelength of the electromagnetic waves and generates a magnetic field in a direction perpendicular to the direction in which the electromagnetic waves are guided and penetrating the first conductive layer and the second conductive layer. The second conductive layer includes a conductor having a second shape, said conductor being disposed at a position facing the first conductive layer across the dielectric layer. The second shape is different from the first shape.

Description

Technical Field

[0001] The present invention relates to a wireless power supply sheet, a wireless power supply device, and a wireless power supply system.

Background Art

[0002] In recent years, research and development and commercialization of wireless power transmission (Wireless Power Transmission: WPT), typified by non-contact charging for smartphones, wearable terminals, and electric vehicles, have become active. For example, Patent Document 1 discloses a technique for shortening the wavelength of electromagnetic waves propagated in a power supply sheet and improving power supply efficiency by using a meander-shaped conductor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, it is also desirable that the power supply sheet be used outdoors. In this case, it is desirable not to be affected by water such as rain.

[0005] In view of the above circumstances, the present invention aims to provide a two-dimensional wireless power supply sheet and a wireless power supply system that are less affected by water and the like.

Means for Solving the Problems

[0006] According to one aspect of the present invention, a two-dimensional wireless power transmission sheet is provided. This two-dimensional wireless power transmission sheet comprises a dielectric layer, a first conductive layer, and a second conductive layer. The dielectric layer is sandwiched between the first conductive layer and the second conductive layer, thereby guiding electromagnetic waves in a predetermined one direction. The first conductive layer includes a conductor of a first shape. The first shape is such that it shortens the wavelength of electromagnetic waves and generates a magnetic field perpendicular to the direction in which the electromagnetic waves are guided, and that it penetrates the first and second conductive layers. The second conductive layer includes a conductor of a second shape, which is disposed opposite the first conductive layer across the dielectric layer. The second shape is different from the first shape.

[0007] According to one aspect of the present invention, it becomes possible to supply power using a magnetic field, thereby reducing the influence of water and other elements. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing the configuration of the two-dimensional wireless power transfer sheet 10. [Figure 2] This is a diagram illustrating the overview of the power supply. [Figure 3] This figure shows an example of the shape of a planar coil. [Figure 4] This figure shows an example of the shape of a planar coil. [Figure 5] This figure shows an example of the shape of a planar coil. [Figure 6] This figure shows an example of the shape of a planar coil. [Figure 7] This diagram shows a first shape and a second shape, both containing multiple planar coils. [Figure 8] This diagram shows a first shape and a second shape, both containing multiple planar coils. [Figure 9] This is a diagram illustrating the magnetic field generated by the two-dimensional wireless power transfer sheet 10. [Figure 10] This figure shows alternative examples of a first shape and a second shape, both containing multiple planar coils. [Figure 11] This is a diagram illustrating the basics of reflection control. [Figure 12] The two-dimensional wireless power supply sheet 10, the power supply unit 20, the reflection control unit 30, and the power receiving terminal 50 are represented by a circuit. [Figure 13] It is a diagram showing an equivalent circuit of the circuit shown in FIG. 12. [Figure 14] It is a diagram showing an example of the configuration of the wireless power supply device. [Figure 15] It is a diagram showing an enlarged view of the coil element. [Figure 16] It is a diagram showing an example of the waveform drawn by the magnetic field. [Figure 17] It is a diagram showing an example of the emitted magnetic field. [Figure 18] It is a diagram showing another example of the emitted magnetic field. [Figure 19] It is a diagram showing another example of the configuration of the wireless power supply device. [Figure 20] It is a diagram showing another example of the configuration of the wireless power supply device.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments and modified examples of the present disclosure will be described with reference to the drawings. Various characteristic matters shown in the embodiments and modified examples shown below can be combined with each other.

[0010] <Embodiment 1> By the way, in the present embodiment, the "unit" may include, for example, hardware resources implemented by a circuit in a broad sense and information processing of software that can be specifically realized by these hardware resources. Further, although various information is handled in the present embodiment, these information is represented by, for example, physical values of signal values representing voltage and current, the level of signal values as a set of binary bits composed of 0 or 1, or quantum superposition (so-called quantum bits), and communication and calculation can be executed on a circuit in a broad sense.

[0011] Furthermore, a circuit in a broad sense is a circuit realized by combining at least a suitable combination of circuits, circuits, processors, and memory. In other words, it includes application-specific integrated circuits (ASICs), programmable logic devices (for example, simple programmable logic devices (SPLDs), complex programmable logic devices (CPLDs), and field programmable gate arrays (FPGAs)), etc.

[0012] 1. Example Configuration Figure 1 is a perspective view showing the configuration of a two-dimensional wireless power transmission sheet 10. As shown in the figure, the two-dimensional wireless power transmission sheet 10 comprises a dielectric layer 11, a first conductive layer 12, and a second conductive layer 13. A power transmission unit (not shown) is connected to one end of the first conductive layer 12 and the second conductive layer 13 in the x-axis direction, and a voltage is applied between them. The other ends of the first conductive layer 12 and the second conductive layer 13 in the x-axis direction are electrically connected. The dielectric layer 11 has a flat plate shape and, sandwiched between the first conductive layer 12 and the second conductive layer 13, guides electromagnetic waves in a predetermined one direction. The direction in which electromagnetic waves are guided is the x-axis direction shown in the figure. The first conductive layer 12 is arranged so as to be in contact with one surface of the dielectric layer 11 and includes a conductor of the first shape described later. Furthermore, the second conductive layer 13 is positioned opposite the first conductive layer 12, with the dielectric layer 11 in between, and includes a conductor of a second shape, which will be described later. This second shape is different from the first shape. As the dielectric layer 11, materials with low relative permittivity ε and high durability, such as polystyrene (relative permittivity ε = 2.4 to 2.6) and polypropylene (relative permittivity ε = 2.0 to 2.3), may be used as appropriate. In addition to dense materials, it may also be composed of hollow structures made of dielectric material, such as dielectric foam or honeycomb structures. Furthermore, as the conductors included in the first conductive layer 12 and the second conductive layer 13, materials with high conductivity, such as gold, silver, copper, aluminum, and iron, may be used as appropriate.

[0013] Preferably, when laying the two-dimensional wireless power transmission sheet 10 on a road or floor surface, covering the surface with an insulator several millimeters thick can significantly reduce the absorption and scattering of electromagnetic waves when the two-dimensional wireless power transmission sheet 10 comes into contact with a human body or other objects.

[0014] Here, we will explain the energy flow during power supply using the two-dimensional wireless power supply sheet 10. Figure 2 is a diagram illustrating the overview of power supply. In the two-dimensional wireless power supply sheet 10, electromagnetic waves EM propagate in the x-axis direction within the dielectric layer 11, and these electromagnetic waves EM are emitted outside the two-dimensional wireless power supply sheet 10 as a magnetic field H. The receiving terminal 50 then receives power by magnetically coupling with this magnetic field H. The magnetic field H can be generated by at least the first shape of the conductor contained in the first conductor. Therefore, the first shape needs to be such that it generates a magnetic field perpendicular to the direction in which the electromagnetic waves EM are guided (x-axis direction) and in the direction that penetrates the first conductive layer 12 and the second conductive layer 13 (z-axis direction). Furthermore, it is desirable that the first shape shortens the wavelength of the electromagnetic waves.

[0015] 2. Conductor shape First, we will explain the first shape, which is the shape of the conductor contained in the first conductive layer 12, and the second shape, which is the shape of the conductor contained in the second conductive layer 13. As mentioned above, the first and second shapes are shapes that generate a magnetic field and also shorten the wavelength of electromagnetic waves. The wavelength λ of the electromagnetic wave propagating in the dielectric layer 11 can be expressed by Equation 1. In Equation 1, L is the reactance of the first conductive layer 12 and the second conductive layer 13, C is the capacitance between the first conductive layer 12 and the second conductive layer 13, and ω is the angular frequency of the electromagnetic wave.

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[0016] Therefore, by increasing the reactance L of the first conductive layer 12 and the second conductive layer 13, and the capacitance C between the first conductive layer 12 and the second conductive layer 13, the wavelength of electromagnetic waves can be shortened. In addition, the reactance L of the first conductive layer 12 and the second conductive layer 13 affects the strength of the magnetic field generated from the two-dimensional wireless power transmission sheet 10, and the stronger the reactance L, the stronger the generated magnetic field. For this reason, it is desirable to increase the reactance L of the first conductive layer 12 and the second conductive layer 13.

[0017] As a method for increasing the reactance L of the first conductive layer 12 and the second conductive layer 13, a coil is included in at least one of the first conductive layer 12 and the second conductive layer 13. Preferably, this coil is a planar coil formed by arranging a spiral coil in a plane. Therefore, the first shape is a shape that includes at least one planar coil. In this case, the second shape does not have to include a planar coil. Of course, the second shape may also include a planar coil. Also, if the first shape does not include a planar coil, the second shape will include at least one planar coil. Of course, both the first and second shapes may include planar coils. In this case, the winding direction of the planar coil of the conductor included in the first shape, that is, the planar coil of the conductor included in the first conductive layer 12, and the planar coil of the conductor included in the second conductive layer 13 will be different. This is to match the direction of the generated magnetic field.

[0018] Here, we show examples of the shapes of planar coils. Figures 3 to 6 are diagrams showing examples of planar coil shapes. The first shape includes planar coil 12-1, planar coil 12-2, planar coil 12-3, planar coil 12-4, etc. The second shape includes planar coils that are inverted versions of planar coil 12-1, planar coil 12-2, planar coil 12-3, planar coil 12-4, etc.

[0019] Incidentally, in the case of a planar coil, for example, planar coil 12-1, the magnetic field generated when current flows is strongest at the center and weakens as you move away from the center. For this reason, by including multiple coils in the first and second shapes, the strength of the generated magnetic field can be made nearly uniform. Figures 7 and 8 show the first and second shapes, which include multiple planar coils. In the example shown here, the first shape is a shape that includes multiple planar coils 12-1 or planar coils 12-2 arranged continuously in the direction in which the electromagnetic waves are guided (x direction). The second shape is a shape that includes multiple planar coils 13-1 or planar coils 13-2 arranged continuously in the direction in which the electromagnetic waves are guided (x direction). In this case, it is preferable that the centers of the planar coils 12-1 etc. included in the first conductive layer (first shape) and the centers of the planar coils 13-1 etc. included in the second conductive layer (second shape) are at different positions on the xy plane with respect to the direction in which the electromagnetic waves are guided, that is, on the xy plane. Furthermore, it is desirable that the centers of the planar coils 12-1 etc. included in the second conductive layer (second shape) and the centers between adjacent planar coils 12-1 etc. included in the first conductive layer (first shape) are at the same position. This is because by making the centers of planar coil 12-1 and planar coil 13-1 different, the strength of the generated magnetic field can be made nearly uniform.

[0020] Figure 9 is a diagram illustrating the magnetic field generated by the two-dimensional wireless power transmission sheet 10. The solid arrows in the figure represent a portion of the magnetic field lines generated by the planar coil included in the first shape, for example, planar coil 12-1, while the dashed arrows represent a portion of the magnetic field lines generated by the planar coil included in the second shape, for example, planar coil 13-1. Furthermore, arrow 12H is the center of the magnetic field generated by the planar coil included in the first shape, and arrow 13H is the center of the magnetic field generated by the planar coil included in the second shape. By positioning the centers of the planar coils included in the first shape and the second shape differently in this way, the strength of the generated magnetic field becomes closer to a uniform state.

[0021] Furthermore, while the planar coil 13-1 shown in Figure 7 is an inverted version of the planar coil 12-1, and the planar coil 13-2 shown in Figure 8 is an inverted version of the planar coil 12-2, the planar coils included in the second shape are not limited to inverted versions of the planar coils included in the first shape. The first and second shapes may each include planar coils of different shapes. Figure 10 shows another example of a first and second shape containing multiple planar coils. In the example shown in this figure, the first shape includes planar coil 13-1, and the second shape includes planar coil 13-4. Although not shown, the first and second shapes may each include planar coils of different shapes.

[0022] 3. Design Examples Here, we will describe a design example of a two-dimensional wireless power transmission sheet 10. Here, the examples shown in Figure 7 were adopted for the first and second shapes, with a length of 1m in the x-direction and a length of 200mm in the y-direction. In this configuration, the two-dimensional wireless power transmission sheet 10 had a relative permittivity of 2.2, a characteristic impedance of 50Ω, a sheet inductance of 13.4μH, a sheet resistance of 8.79Ω, a sheet Q value of 65, a sheet capacitance of 5.36pF, and a propagation loss of -0.706dB / m. When a voltage of 6.78MHz is applied to the two-dimensional wireless power transmission sheet 10 with this configuration from a power transmission point (not shown), the half-wavelength of the electromagnetic wave within the sheet is approximately 23mm. Therefore, by arranging a power receiving coil with a diameter of approximately 10-20mm at the power receiving terminal 50, it becomes possible to supply power to the power receiving terminal 50.

[0023] 4. Reflection control Next, the reflection control of electromagnetic waves at the edges of the two-dimensional wireless power transmission sheet 10 will be described. Reflection control is achieved by providing the two-dimensional wireless power transmission sheet 10 with a reflection control unit 30. Figure 11 is a diagram illustrating the overview of the reflection control.

[0024] Reflection control is performed by connecting a reflection control unit 30 to the two-dimensional wireless power supply sheet 10, as shown in Figure 11. The reflection control unit 30 is located at the other end when the power supply unit 20 is connected to one end in the direction in which the electromagnetic wave EM is guided (in the x-axis direction), and controls the reflection of the electromagnetic wave EM at this other end. This control by the reflection control unit 30 cancels out the reflected electromagnetic wave that is reflected at the position of the power receiving terminal 50 when the power receiving terminal 50 is located between the one end and the other end due to the reflected wave from the other end.

[0025] Referring to Figure 11, when a voltage is applied to the two-dimensional wireless power transmission sheet 10 by the power supply unit 20, the electromagnetic wave EM propagating within the two-dimensional wireless power transmission sheet 10 is mostly supplied to the power receiving terminal 50 via a magnetic field, with the majority being electromagnetic wave EM1. At this time, a portion of the electromagnetic wave EM is reflected as electromagnetic wave EM2 at the location of the power receiving terminal 50, and another portion of the electromagnetic wave EM is reflected as electromagnetic wave EM3 by the reflection control unit 30. At this time, the reflection control unit 30 controls the reflected electromagnetic wave EM3 to cancel out electromagnetic wave EM2. This makes it possible to reduce or eliminate electromagnetic waves EM2 and EM3, and as a result, the impact on the electromagnetic wave EM can be reduced. Specifically, the reflection control unit 30 can be realized by including a circuit having an impedance corresponding to circuit constants including the circuit constants of the dielectric layer 11, the first conductive layer 12, and the second conductive layer 13.

[0026] Here, if we represent the two-dimensional wireless power transfer sheet 10, the power supply unit 20, the reflection control unit 30, and the power receiving terminal 50 as a circuit, the circuit will be as shown in Figure 12. Figure 12 shows the two-dimensional wireless power transfer sheet 10, the power supply unit 20, the reflection control unit 30, and the power receiving terminal 50 as a circuit.

[0027] Furthermore, Figure 13 shows the equivalent circuit of the circuit shown in Figure 12. In this equivalent circuit shown in Figure 13, the part indicated by symbol A in Figure 12 is replaced with a power supply with impedance Z0, the coil included in the two-dimensional wireless power transmission sheet 10 (such as a planar coil included in the first conductive layer 12) and the receiving coil included in the receiving terminal 50 in the part indicated by symbol B in Figure 12 are replaced with a magnetic field coupling circuit with coefficient k, and the part from the position of the receiving terminal 50 to the reflection control unit 30 in the part indicated by symbol C in Figure 12 is replaced with impedance Z term2 This is a replacement for L in Figure 13. m This is the reactance of the magnetic field-coupled circuit.

[0028] The calculations performed using the equivalent circuit shown in Figure 13 show that when equations 2 and 3 are satisfied, and when equation 4 is satisfied, electromagnetic waves EM2 and EM3 cancel each other out. From these calculation results, it is possible to identify the impedance included in the reflection control unit 30.

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[0029] Furthermore, using the equivalent circuit shown in Figure 13, the case in which the power supply efficiency to the power receiving terminal 50 is maximized is calculated, and the result shown in Equation 5 is obtained. Note that in the equation shown in Equation 5, R Lopt This is R when the power supply efficiency is maximized. L This means that the efficiency can be maximized by adjusting the reflection control unit 30.

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[0030] 7. Other A wireless power supply system can be configured by providing the two-dimensional wireless power supply sheet 10 described above and a power receiving terminal 50. In this case, as mentioned above, it is desirable that the power receiving terminal 50 be equipped with a power receiving coil that is less than or equal to half the wavelength of the electromagnetic waves propagating within the two-dimensional wireless power supply sheet 10.

[0031] <Embodiment 2> In Embodiment 1, the coil included in the first conductive layer 12 and the coil included in the second conductive layer 13 form a capacitor. In Embodiment 1, the conductive layer formed by arranging the coils that form the capacitor (the layer including the first conductive layer 12 and the second conductive layer 13) was one (i.e., one layer), but it may be two or more (i.e., two or more layers).

[0032] Figure 14 shows an example of the configuration of a wireless power supply device. The wireless power supply device 2a shown in Figure 14 is a device that wirelessly supplies power to the power receiving terminal 50 shown in Figure 2, and comprises a two-dimensional wireless power supply sheet 10a and a power supply unit 20a. Similar to the two-dimensional wireless power supply sheet 10 shown in Figure 1, the two-dimensional wireless power supply sheet 10a transmits electromagnetic waves by passing an alternating current through it, and the magnetic field (also called a magnetic field) formed when the electromagnetic waves are emitted outside the two-dimensional wireless power supply sheet 10a magnetically couples with the power receiving terminal 50, thereby supplying power to the power receiving terminal 50.

[0033] The two-dimensional wireless power transmission sheet 10a is a sheet-like device that stretches in the stretching direction D2 and transmits electromagnetic waves in the transmission direction D1. For example, the two-dimensional wireless power transmission sheet 10a has dimensions such as a length of several tens of centimeters to several meters in the stretching direction D2, a thickness of several millimeters in the thickness direction D3, and a width of several tens of centimeters in the width direction D4. Note that these dimensions are just an example and can be changed as needed.

[0034] The power supply unit 20a is a power source that supplies alternating current to the two-dimensional wireless power supply sheet 10a. The power supply unit 20a comprises a power supply unit 21a, a power supply unit 22a, and a power supply unit 23a. On the other hand, the two-dimensional wireless power supply sheet 10a comprises a first conductive layer 41a, a second conductive layer 42a, and a third conductive layer 43a. As described above, the first conductive layer 41a, the second conductive layer 42a, and the third conductive layer 43a are conductive layers that each include a coil forming a capacitor.

[0035] The power supply unit 21a is connected to the end of the first conductive layer 41a in the extension direction D2 (the end opposite to the transmission direction D1; the same applies hereinafter) and supplies alternating current to the first conductive layer 41a. The power supply unit 22a is connected to the end of the second conductive layer 42a in the extension direction D2 and supplies alternating current to the second conductive layer 42a. The power supply unit 23a is connected to the end of the third conductive layer 43a in the extension direction D2 and supplies alternating current to the third conductive layer 43a.

[0036] The first conductive layer 41a comprises a first circuit section 61a and a second circuit section 71a. A power supply section 21a is connected between the first circuit section 61a and the second circuit section 71a, and alternating current is supplied from the power supply section 21a to the first circuit section 61a and the second circuit section 71a. The alternating current supplied by the power supply section 21a flows while alternately switching between a direction toward the power supply section 21a and a direction toward the power supply section 21a, but the direction of the current flowing through the first circuit section 61a and the direction of the current flowing through the second circuit section 71a are opposite. In other words, when the current toward the power supply section 21a flows through the first circuit section 61a, the current moving away from the power supply section 21a flows through the second circuit section 71a, and when the current moving away from the power supply section 21a flows through the first circuit section 61a, the current toward the power supply section 21a flows through the second circuit section 71a.

[0037] The first circuit section 61a and the second circuit section 71a form a plurality of coil elements 80a and a plurality of coil elements 90a. The coil elements 80a and 90a are arranged alternately along the extension direction D2.

[0038] The coil element 80a has a first coil 81a and a second coil 82a. The first coil 81a and the second coil 82a share a common axis, and their winding directions (the direction in which the wire is wound) are opposite. In the example in Figure 14, when viewed from above in the figure, the first coil 81a is wound clockwise, and the second coil 82a is wound counterclockwise.

[0039] The first coil 81a is a coil formed by the first circuit section 61a, and the second coil 82a is a coil formed by the second circuit section 71a. As mentioned above, the direction of the current flowing through the first circuit section 61a and the direction of the current flowing through the second circuit section 71a are opposite, so when alternating current flows through the first circuit section 61a and the first circuit section 62a, the magnetic fields generated by the first coil 81a and the second coil 82a at the same time will be in the same direction. Note that the direction of the magnetic field generated when alternating current flows through a coil changes according to the change in the direction and strength of the alternating current (the same applies to the following coils).

[0040] Note that although the coils shown in Figure 14 have their wires wound in a spiral shape, this is merely a representation to make the winding direction easier to understand, and the coils are not necessarily wound in a spiral. Also, the phrase "shape is common" for the first coil 81a and the second coil 82a does not mean that the axis positions are not perfectly aligned; a slight misalignment is acceptable. However, the larger the misalignment, the greater the cancellation between the magnetic field generated by the first coil 81a and the magnetic field generated by the second coil 82a, so a smaller axis misalignment is desirable. These points will also apply to subsequent figures.

[0041] The coil element 90a has a first coil 91a and a second coil 92a. The first coil 91a and the second coil 92a share a common axis and are wound in opposite directions. Furthermore, the coil element 90a is wound in the opposite direction to that of the coil element 80a. In other words, when viewed from above in the figure, the first coil 91a is wound counterclockwise, and the second coil 92a is wound clockwise.

[0042] The first coil 91a is a coil formed by the first circuit section 61a, and the second coil 92a is a coil formed by the second circuit section 71a. Similar to the case of the coil element 80a, when alternating current flows through the first circuit section 61a and the first circuit section 62a, the magnetic fields generated by the first coil 91a and the second coil 92a are in the same direction at the same timing.

[0043] However, since the winding directions of the coils in coil element 80a and coil element 90a are opposite, the directions of the magnetic fields generated by coil element 80a and coil element 90a at the same time will be opposite. For example, as shown in Figure 14, when an upward magnetic field H1 is generated by coil element 80a, a downward magnetic field H2 is generated by coil element 90a. Therefore, in the first conductive layer 41a, an upward magnetic field H1 and a downward magnetic field H2 are generated alternately. Note that the direction of the magnetic field shown in Figure 14 is the direction at a specific moment, and the direction of the magnetic field will change when the direction of current flow changes.

[0044] The second conductive layer 42a and the third conductive layer 43a have the same configuration as the first conductive layer 41a. The second conductive layer 42a includes a first circuit section 62a and a second circuit section 72a, and a power supply section 22a is connected between the first circuit section 62a and the second circuit section 72a to supply alternating current. The first circuit section 62a and the second circuit section 72a form a plurality of coil elements 80a and a plurality of coil elements 90a, and the coil elements 80a and 90a are arranged alternately along the extension direction D2.

[0045] The third conductive layer 43a comprises a first circuit section 63a and a second circuit section 73a, and a power supply section 23a is connected between the first circuit section 63a and the second circuit section 73a to supply alternating current. The first circuit section 63a and the second circuit section 73a form a plurality of coil elements 80a and a plurality of coil elements 90a, and the coil elements 80a and 90a are arranged alternately along the extension direction D2.

[0046] Coil elements 80a and 90a each form a capacitor. For example, as shown in the example in Figure 2, the first coil 81a and the second coil 82a may be arranged with a derivative in between, and the first coil 91a and the second coil 92a may be arranged with a derivative in between to form capacitors. However, in Embodiment 2, capacitors are formed in a different manner.

[0047] Figure 15 is a magnified view of a coil element. In Figure 15, the first conductive layer 41a is shown in magnification. The coil base 15a shown in Figure 15 is a plate-shaped member that serves as a base for winding a coil, and has grooves on its sides for winding a wire. In the example in Figure 15, multiple coil bases 15a are arranged along the extension direction D2. Each coil base 15a has a rectangular shape when viewed from above, and is arranged so that its long side is along the width direction D4 and its short side is along the extension direction D2.

[0048] First, on the coil base 15a that will serve as the base for the coil element 80a, the wire that will form the first circuit section 61a is wound clockwise when viewed from above, and the wire that will form the second circuit section 71a is wound counterclockwise when viewed from above. Next, on the coil base 15a that will serve as the base for the coil element 90a, the wire that will form the first circuit section 61a is wound counterclockwise when viewed from above, and the wire that will form the second circuit section 71a is wound clockwise when viewed from above. From there, the wires are wound in sequence so that the coil elements 80a and 90a alternate.

[0049] Figure 15 shows a magnified view of a portion of the cross-section of the wires of the coil element 90a. In this magnified view, for ease of identification, the cross-section of the wires of the first circuit section 61a is shown in white, and the cross-section of the wires of the second circuit section 71a is shown in diagonal lines. As the magnified view shows, the wires of the first circuit section 61a and the wires of the second circuit section 71a are in close contact with each other. Each wire is a wire with a coating, such as magnet wire or Litz wire, and the coating acts as a derivatizer to form a capacitor. Thus, both the coil element 80a and the coil element 90a include coils that form a capacitor (first coil 81a and second coil 82a, and first coil 91a and second coil 92a).

[0050] As shown in Figure 14, the coil elements 80a and 90a of the first conductive layer 41a, the second conductive layer 42a, and the third conductive layer 43a are offset by a length L1 in the transmission direction D1 (extension direction D2) of their respective axes. Length L1 is one-third of the length in the transmission direction D1 of coil element 80a and one-third of the length in the transmission direction D1 of coil element 90a.

[0051] A coil element 80a of the second conductive layer 42a is positioned at a distance L1 in the transmission direction D1 from a coil element 80a of the third conductive layer 43a, and a coil element 80a of the first conductive layer 41a is positioned at a distance L1 in the transmission direction D1 from a coil element 80a of the second conductive layer 42a. Furthermore, a coil element 90a of the third conductive layer 43a is positioned at a distance L1 in the transmission direction D1 from a coil element 80a of the first conductive layer 41a. In this way, the coil elements 80a and 90a of the first conductive layer 41a, the second conductive layer 42a, and the third conductive layer 43a are repeatedly positioned with a distance L1 each.

[0052] In the two-dimensional wireless power transmission sheet 10a, the power supply units 21a, 22a, and 23a supply alternating current, generating magnetic fields in the first conductive layer 41a, the second conductive layer 42a, and the third conductive layer 43a, respectively. Here, the power supply units 21a, 22a, and 23a each supply alternating current with a phase difference of 120 degrees, so-called three-phase alternating current. As the three-phase alternating current flows through the first conductive layer 41a, the second conductive layer 42a, and the third conductive layer 43a, the magnetic field emitted outside the two-dimensional wireless power transmission sheet 10a exhibits a smoother waveform compared to the case with only one conductive layer.

[0053] Figure 16 shows an example of a waveform drawn by a magnetic field. In Figure 16, the vertical axis represents the magnetic field strength, and the horizontal axis represents the position in the transmission direction D1. The magnetic field strength is shown with the horizontal axis position set to "0", and the strength when the magnetic field is upward and the strength when the magnetic field is downward are shown separately.

[0054] On the horizontal axis, the axis position of the coil element 80a on the third conductive layer 43a is "0", the axis position of the coil element 80a on the second conductive layer 42a is "0.5", the axis position of the coil element 80a on the first conductive layer 41a is "1", the axis position of the coil element 90a on the third conductive layer 43a is "1.5", the axis position of the coil element 90a on the second conductive layer 42a is "2", the axis position of the coil element 90a on the first conductive layer 41a is "2.5", and the axis position of the coil element 80a on the third conductive layer 43a is "3". The spacing of each coil element in the transmission direction D1 is "L1".

[0055] For example, at position "1", the magnetic field strength is a composite of the magnetic fields generated not only by the coil element 80a of the first conductive layer 41a, but also by the coil elements 80a of the preceding and succeeding second conductive layer 42a and the coil element 90a of the third conductive layer 43a. Figures 16(a), (b), and (c) show that the waveform of the magnetic field strength shifts in the transmission direction D1 over time. By shifting the phase of each of the three conductive layers by 120 degrees and reversing the winding direction of coil elements 80a and 90a, the magnetic field strength exhibits a smoother waveform compared to, for example, a case where the phase of the alternating current is not changed and the winding direction of adjacent coil elements is not changed.

[0056] Figure 17 shows an example of an emitted magnetic field. Figure 17 shows the simulation results of the magnetic field generated when a 3-phase AC current with a frequency of 100 kHz is passed through a 500 mm long two-dimensional wireless power transmission sheet 10a. As shown in Figure 17, an upward magnetic field H1 and a downward magnetic field H2 are alternately emitted outside the two-dimensional wireless power transmission sheet 10a. The length containing one magnetic field H1 and one magnetic field H2 represents one wavelength, and in the example in Figure 17, a magnetic field equivalent to 2.5 wavelengths is generated, so one wavelength is approximately 200 mm.

[0057] Figure 18 shows another example of the emitted magnetic field. Figure 18 shows the simulation results of the magnetic field generated when a 100kHz three-phase alternating current is passed through a two-dimensional wireless power transmission sheet 10x (length 500mm) in which each of the three conductive layers has only a first coil. In the example in Figure 18, a magnetic field of two wavelengths is generated, so one wavelength is approximately 250mm. Thus, compared to the two-dimensional wireless power transmission sheet 10x, the two-dimensional wireless power transmission sheet 10a has conductive layers (first conductive layer 41a, second conductive layer 42a, and third conductive layer 43a) arranged with coils (coil elements 80a and 90a) each forming a capacitor, which slows down the speed at which the composite wave of the magnetic field generated by each conductive layer propagates, i.e., the group velocity. As a result, magnetic coupling between the generated magnetic field and the power receiving terminal 50 is easier compared to the example in Figure 18, and the power supply efficiency to the power receiving terminal 50 can be increased.

[0058] As described above, the two-dimensional wireless power transmission sheet 10a is an example of a wireless power transmission sheet that has N (N is a natural number of 2 or more) or more conductive layers in which multiple coil elements are arranged in the transmission direction. In the two-dimensional wireless power transmission sheet 10a, N is 3, and it has three conductive layers: a first conductive layer 41a, a second conductive layer 42a, and a third conductive layer 43a. These N or more conductive layers function as waveguides for transmitting electromagnetic waves.

[0059] Furthermore, in each conductive layer, multiple coil elements, namely multiple coil elements 80a and multiple coil elements 90a, are arranged in the transmission direction D1. Each coil element has a first coil and a second coil. In the example in Figure 14, coil element 80a has a first coil 81a and a second coil 82a, and coil element 90a has a first coil 91a and a second coil 92a. These second coils share an axis with the first coil and have opposite winding directions.

[0060] The transmission direction D1 is the direction in which electromagnetic waves are transmitted through the waveguide when an alternating current flows through a circuit that includes a first circuit section 61a in which multiple first coils are connected in series and a second circuit section 71a in which multiple second coils are connected in series. The positions of the coil elements in the N or more conductive layers are offset from each other in the transmission direction D1. In the two-dimensional wireless power transmission sheet 10a, the positions of the coil elements 80a and 90a included in the first conductive layer 41a, the second conductive layer 42a, and the third conductive layer 43a in the transmission direction D1 are offset by a length L1, as shown in Figure 14.

[0061] If the positions of the coil elements in each conductive layer coincide in the transmission direction D1, a strong magnetic field is generated at the axis of each coil element, but the magnetic field weakens in the region between the axes. In contrast, as described above, the positions of the coil elements in each conductive layer are offset in the transmission direction D1, which shortens the distance between the axes of each coil element, reduces the region where the magnetic field is weak, and allows for a more uniform magnetic field to be generated overall.

[0062] In Embodiment 1, the strength of the generated magnetic field was made nearly uniform by placing the center of the planar coil included in the first shape (corresponding to the first coil) and the center of the planar coil included in the second shape (corresponding to the second coil) at different positions; however, this is the case when there is only one conductive layer. When there are two or more conductive layers, as in Embodiment 2, the axes of a single coil element (a pair of first and second coils) may be common, and the uniformity of the magnetic field can be improved by shifting the axes of coil elements from different conductive layers. By making the axes of a single coil element common, the distance between the first and second coils becomes shorter compared to when the axes are shifted, increasing the capacitance of the capacitor formed by the coil elements and slowing down the group velocity (the speed at which the composite wave of the magnetic field propagates) as described above.

[0063] Furthermore, in N or more conductive layers, the positions of the coil elements in the transmission direction D1 are offset from each other by 1 / N of the length of the transmission direction D1 of the coil elements. In the example in Figure 14, the number of conductive layers N is 3, and the position of each coil element (coil element 80a and coil element 90a) in the transmission direction D1 is offset by a length L1, which is one-third of the length of the transmission direction D1 of each coil element. By making the offset of the coil elements uniform in this way, the uniformity of the generated magnetic field can be further improved compared to the case where the offset of the coil elements is non-uniform.

[0064] Furthermore, in the two-dimensional wireless power transfer sheet 10a, as described above, the number of conductive layers N is 3. Increasing the number of conductive layers makes it easier to make the strength of the electromagnetic waves uniform, but the sheet becomes thicker as more layers are added. By setting N to 3, it is possible to prevent the sheet from becoming too thick compared to the case of more layers, while improving the uniformity of the electromagnetic waves compared to the case of two layers, that is, to achieve both thinness of the sheet and uniformity of the electromagnetic waves.

[0065] Furthermore, in the two-dimensional wireless power transmission sheet 10a, in each conductive layer, a plurality of first coils are connected so that their winding directions alternately opposite to each other to form a first circuit section, and a plurality of second coils are connected so that their winding directions alternately opposite to each other to form a second circuit section. For example, in Figure 14, the first coil 81a has the wire wound clockwise when viewed from above, the first coil 91a has the wire wound counterclockwise when viewed from above, the second coil 82a has the wire wound counterclockwise when viewed from above, and the second coil 92a has the wire wound clockwise when viewed from above.

[0066] Note that the coil winding direction shown in Figure 14 is just one example; for example, the winding direction of multiple first coils may all be the same, and the winding direction of multiple second coils may all be the same (however, the winding directions of the first and second coils are opposite). By making the winding direction of all coil elements the same in this way, the uniformity of the generated magnetic field can be improved compared to when the winding direction is varied.

[0067] On the other hand, the magnetic field generated by the coil element traces a trajectory that is emitted from the two-dimensional wireless power transmission sheet 10a and then returns, as shown in Figure 9. Therefore, cancellation occurs between the returning portion and the emitted portion. This cancellation occurs when the directions of the magnetic fields generated by the coil elements are the same, as shown in Figure 9. Therefore, as in the example in Figure 14, by alternating the winding directions of the coil elements, the cancellation of magnetic fields between adjacent coil elements is reduced compared to the case where all winding directions are the same, and electromagnetic waves can be transmitted in a low-loss state.

[0068] Furthermore, the first coil (first coil 81a and first coil 91a) and the second coil (second coil 82a and second coil 92a) are formed from conductive wires coated with a dielectric, and as shown in Figure 15, the conductive wires of the first coil and the conductive wires of the second coil are in close contact. With this configuration, a capacitor is formed by simply winding conductive wires around a member such as the coil base 15a shown in Figure 15, so a coil that functions as a capacitor can be easily created compared to a configuration in which a dielectric layer is sandwiched between two conductive layers, as in the example in Figure 2.

[0069] Furthermore, as described above, the wireless power supply device 2a comprises a two-dimensional wireless power supply sheet 10a and a power supply unit 20a. The power supply unit 20a is connected to one end of the two-dimensional wireless power supply sheet 10a and supplies alternating current to the first circuit section (first circuit sections 61a, 62a, 63a) and the second circuit section (second circuit sections 71a, 72a, 73a). With this configuration, the need to provide a separate power supply can be eliminated.

[0070] <Modified version: 2 layers + 2 phases> In Embodiment 2, a three-phase alternating current was supplied from three power supply units to three conductive layers (conductive layers formed by arranging coils that form a capacitor). However, the number of conductive layers (N) and the number of power supply units are not limited to these. For example, a case where there are two conductive layers (N=2) and two power supply units supply a two-phase alternating current will be described.

[0071] Figure 19 shows another example of the configuration of a wireless power supply device. The wireless power supply device 2b shown in Figure 19 comprises a two-dimensional wireless power supply sheet 10b and a power supply unit 20b. The two-dimensional wireless power supply sheet 10b comprises a first conductive layer 41b and a second conductive layer 42b. The first conductive layer 41b and the second conductive layer 42b are conductive layers that include coils forming capacitors. The power supply unit 20b comprises a power supply unit 21b and a power supply unit 22b.

[0072] The first conductive layer 41b comprises a first circuit section 61b and a second circuit section 71b. A power supply section 21b is connected between the first circuit section 61b and the second circuit section 71b, and alternating current is supplied from the power supply section 21b to the first circuit section 61b and the second circuit section 71b. The first circuit section 61b and the second circuit section 71b form a plurality of coil elements 80b. Each coil element 80b has a first coil 81b and a second coil 82b. The first coil 81b and the second coil 82b are coils that share a common axis and have opposite winding directions.

[0073] The first coil 81b is a coil formed by the first circuit section 61b, and the second coil 82b is a coil formed by the second circuit section 71b. Since the direction of the current flowing through the first circuit section 61b and the direction of the current flowing through the second circuit section 71b are opposite, the direction of the magnetic fields generated by the first coil 81b and the second coil 82b when alternating current flows through the first circuit section 61b and the first circuit section 62b will be the same. Also, in the example in Figure 19, the direction of the magnetic fields generated by multiple coil elements 80b at the same timing will all be the same.

[0074] The second conductive layer 42b has the same configuration as the first conductive layer 41b. The second conductive layer 42b includes a first circuit section 62b and a second circuit section 72b, and a power supply section 22b is connected between the first circuit section 62b and the second circuit section 72b to supply alternating current. The first circuit section 62b and the second circuit section 72b form a plurality of coil elements 80b. The plurality of coil elements 80b in the second conductive layer 42b all generate magnetic fields in the same direction at the same timing. Note that the direction of the magnetic field H1 shown in Figure 19 only indicates that the direction of the magnetic field in each conductive layer is the same; the direction and strength of the magnetic field generated differ depending on the phase of the alternating current supplied to each conductive layer.

[0075] As shown in Figure 19, the coil elements 80b of the first conductive layer 41b and the second conductive layer 42b are offset by a length L2 in the transmission direction D1 (extension direction D2) of their respective axes. The length L2 is half the length of the coil element 80b in the transmission direction D1.

[0076] In the two-dimensional wireless power transmission sheet 10b, the power supply units 21b and 22b supply alternating current, generating magnetic fields in the first conductive layer 41b and the second conductive layer 42b, respectively. By using two conductive layers in this way, a more uniform magnetic field can be generated compared to the case where only one conductive layer is used. Furthermore, the power supply units 21b and 22b each supply alternating current with a phase difference of 180 degrees, so-called two-phase alternating current. This reduces the cancellation of magnetic fields between adjacent coil elements compared to the case where alternating currents with the same phase are flowed, enabling the transmission of electromagnetic waves in a low-loss state.

[0077] <Modified version: 2 layers + single phase> It is also possible to supply single-phase AC current from a single power supply unit to two conductive layers (N=2).

[0078] Figure 20 shows another example of the configuration of a wireless power supply device. The wireless power supply device 2c shown in Figure 20 comprises a two-dimensional wireless power supply sheet 10c and a power supply unit 21c. The two-dimensional wireless power supply sheet 10c comprises a first conductive layer 41c and a second conductive layer 42c. The first conductive layer 41c and the second conductive layer 42c are conductive layers that include coils forming capacitors. The first conductive layer 41c and the second conductive layer 42c comprise a first circuit section 61c and a second circuit section 71c. In other words, both the first conductive layer 41c and the second conductive layer 42c are formed by the first circuit section 61c and the second circuit section 71c.

[0079] A power supply unit 21c is connected between the first circuit section 61c and the second circuit section 71c, and alternating current is supplied from the power supply unit 21c to the first circuit section 61c and the second circuit section 71c. The first circuit section 61c and the second circuit section 71c form a plurality of coil elements 80c. Each coil element 80c has a first coil 81c and a second coil 82c. The first coil 81c and the second coil 82c are coils that share a common axis and have opposite winding directions.

[0080] The first coil 81c is a coil formed by the first circuit section 61c, and the second coil 82c is a coil formed by the second circuit section 71c. The first circuit section 61c first forms the first coil 81c of the second conductive layer 42c, then forms the first coil 81c of the first conductive layer 41c, and then again forms the first coil 81c of the second conductive layer 42c. In this way, the first circuit section 61c repeatedly forms the first coil 81c of the second conductive layer 42c and the first coil 81c of the first conductive layer 41c in sequence, and these first coils 81c are connected in series.

[0081] The second circuit section 71c first forms a second coil 82c of the second conductive layer 42c, then forms a second coil 82c of the first conductive layer 41c, and then again forms a second coil 82c of the second conductive layer 42c. In this way, the second circuit section 71c repeatedly forms a second coil 82c of the second conductive layer 42c and a second coil 82c of the first conductive layer 41c in sequence, and these second coils 82c are connected in series.

[0082] As shown in Figure 20, the coil elements 80c of the first conductive layer 41c and the second conductive layer 42c are offset by a length L2 in the transmission direction D1 (extension direction D2) of their respective axes. Length L2 is half the length of the coil element 80c in the transmission direction D1. In the two-dimensional wireless power transmission sheet 10c, the power supply unit 21c supplies alternating current, generating magnetic fields in the first conductive layer 41c and the second conductive layer 42c, respectively. The offset in the transmission direction D1 of the coil elements 80c of the first conductive layer 41c and the second conductive layer 42c improves the uniformity of the generated magnetic field compared to the case with a single conductive layer.

[0083] In the example shown in Figure 20, there are two conductive layers, but it is also possible to have three or more conductive layers in a similar configuration, i.e., a configuration in which one set of first and second circuit sections forms coil elements of multiple conductive layers. In either case, the first circuit section is a series circuit formed by sequentially connecting first coils of different conductive layers, and the second circuit section is a series circuit formed by sequentially connecting second coils of different conductive layers. With this configuration, even with a single power supply, alternating current can be passed through two or more conductive layers, and the uniformity of the generated magnetic field can be improved compared to the case with one conductive layer.

[0084] As described above, the number of conductive layers N (where N is a natural number greater than or equal to 2) and the number of power supply units M (where M is a natural number greater than or equal to 1) may or may not be the same (provided N ≥ M). Increasing N shortens the spacing between the axes of the coil elements in the transmission direction D1, thereby improving the uniformity of the magnetic field. However, increasing N also increases the cancellation of magnetic fields between adjacent coil elements. To reduce losses, M may also be increased to shift the phase of the alternating current, or the winding direction of the coil elements may be alternately reversed as in the example in Figure 14, thereby reducing the cancellation of magnetic fields. Alternatively, reducing M may simplify the structure of the device and lower costs.

[0085] <Variations: Other variations> The coil winding method described above is just one example and is not limited to this. For example, one coil may be wound clockwise and another counterclockwise, or vice versa. Also, in the examples in Figures 19 and 20, instead of arranging coil elements with the same winding direction, one may arrange coil elements with different winding directions alternately, as in the example in Figure 14.

[0086] Furthermore, the amount of displacement of the coil elements in each conductive layer (the distance between the axes of each coil element) may be constant or may vary slightly. By varying this displacement, it is possible to intentionally create areas with high and low magnetic field densities. Each coil element may be a planar coil as in Embodiment 1, as long as the axes of the first coil and the second coil are common and the winding directions are opposite. It is also desirable that the number of turns of the conductors in the first coil and the second coil are the same, but they may differ slightly. In addition, the reflection control in Embodiment 1 may be performed in Embodiment 2 and its modifications.

[0087] Furthermore, if there are two or more power supply units, the AC current supplied by each supply unit may have a different phase than in the example above. For example, the phases, which were shifted by 120 degrees in a three-phase AC system, may be shifted by 60 degrees or 90 degrees. In a two-phase AC system, the phases may be shifted by 90 degrees. These phase shifts are just examples, and the phases may be shifted by other angles. Alternatively, the AC current may be supplied without any phase shift. In any case, if the positions of the coil elements in each conductive layer in the transmission direction D1 are offset from each other, a more uniform magnetic field can be generated compared to when these positions coincide.

[0088] The present invention may be provided in any of the following embodiments.

[0089] (1) A two-dimensional wireless power transmission sheet comprising a dielectric layer, a first conductive layer, and a second conductive layer, wherein the dielectric layer is sandwiched between the first conductive layer and the second conductive layer to guide electromagnetic waves in a predetermined one direction, the first conductive layer includes a conductor of a first shape, the first shape shortens the wavelength of the electromagnetic waves and generates a magnetic field perpendicular to the direction in which the electromagnetic waves are guided and penetrating the first conductive layer and the second conductive layer, and the second conductive layer includes a conductor of a second shape disposed opposite the first conductive layer with the dielectric layer in between, the second shape being different from the first shape.

[0090] (2) A two-dimensional wireless power transmission sheet as described in (1) above, wherein the first shape is a shape that includes at least one planar coil.

[0091] (3) A two-dimensional wireless power transmission sheet as described in (2) above, wherein the second shape is a shape that includes at least one planar coil.

[0092] (4) A two-dimensional wireless power transmission sheet as described in (2) above, wherein the first shape is a shape that includes a plurality of planar coils arranged continuously in the direction in which the electromagnetic waves are guided.

[0093] (5) A two-dimensional wireless power transmission sheet as described in (4) above, wherein the second shape is a shape that includes a plurality of planar coils arranged continuously in the direction in which the electromagnetic waves are guided.

[0094] (6) A two-dimensional wireless power transmission sheet as described in (5) above, wherein the center of the planar coil included in the first conductive layer and the center of the planar coil included in the second conductive layer are at different positions with respect to the direction in which the electromagnetic waves are guided.

[0095] (7) A two-dimensional wireless power transmission sheet as described in (6) above, wherein the center of the planar coil included in the second conductive layer and the center between adjacent planar coils included in the first conductive layer are in the same position with respect to the direction in which the electromagnetic waves are guided.

[0096] (8) A two-dimensional wireless power transmission sheet according to any one of (5) to (7) above, wherein the planar coil included in the first conductive layer and the planar coil included in the second conductive layer have different winding directions.

[0097] (9) A two-dimensional wireless power supply sheet according to any one of (1) to (8) above, comprising a reflection control unit, wherein the reflection control unit is disposed at the other end when a power supply circuit is connected to one end in the direction in which the electromagnetic waves are guided, and controls the reflection of the electromagnetic waves at the other end, and the control cancels out the reflected waves of the electromagnetic waves reflected at the position of the power receiving terminal when a power receiving terminal exists between the one end and the other end due to the reflected waves from the reflection at the other end.

[0098] (10) A two-dimensional wireless power transmission sheet as described in (9) above, wherein the reflection control unit includes a circuit having an impedance corresponding to the circuit constants of the dielectric layer, the first conductive layer, and the second conductive layer.

[0099] (11) A wireless power supply system comprising a two-dimensional wireless power supply sheet as described in any one of (1) to (10) above, and a power receiving terminal, wherein the power receiving terminal comprises a power receiving coil having a size of half a wavelength or less of the electromagnetic waves propagated within the two-dimensional wireless power supply sheet. Of course, this is not always the case.

[0100] Finally, various embodiments of the present invention have been described, but these are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of symbols]

[0101] 2a: Wireless power transfer device, 2b: Wireless power transfer device, 2c: Wireless power transfer device, 10: Two-dimensional wireless power transfer sheet, 10a: Two-dimensional wireless power transfer sheet, 10b: Two-dimensional wireless power transfer sheet, 10c: Two-dimensional wireless power transfer sheet, 11: Dielectric layer, 12: First conductive layer, 12-1: Planar coil, 12-2: Planar coil, 12-3: Planar coil, 12-4: Planar coil, 12H: Arrow, 13: Second conductive layer, 13-1: Planar coil, 1 3-2: Planar coil, 13-4: Planar coil, 13H: Arrow, 15a: Coil base, 20: Power supply unit, 20a: Power supply unit, 20b: Power supply unit, 21a: Power supply unit, 21b: Power supply unit, 21c: Power supply unit, 22a: Power supply unit, 22b: Power supply unit, 23a: Power supply unit, 30: Reflection control unit, 41a: First conductive layer, 41b: First conductive layer, 41c: First conductive layer, 42a: Second conductive layer, 42b: Second conductive layer, 42c: Second conductive layer, 43 a: Third conductive layer, 50: Power receiving terminal, 61a: First circuit section, 61b: First circuit section, 61c: First circuit section, 62a: First circuit section, 62b: First circuit section, 63a: First circuit section, 71a: Second circuit section, 71b: Second circuit section, 71c: Second circuit section, 72a: Second circuit section, 72b: Second circuit section, 73a: Second circuit section, 80a: Coil element, 80b: Coil element, 80c: Coil element, 81a: First coil, 81b: 1st coil, 81c: 1st coil, 82a: 2nd coil, 82b: 2nd coil, 82c: 2nd coil, 90a: coil element, 91a: 1st coil, 92a: 2nd coil, C: capacitance, D1: transmission direction, D2: extension direction, D3: thickness direction, D4: width direction, EM: electromagnetic wave, EM1: electromagnetic wave, EM2: electromagnetic wave, EM3: electromagnetic wave, EM4: electromagnetic wave, H: magnetic field, H1: magnetic field, H2: magnetic field, L: reactance

Claims

1. It is a wireless power supply sheet, The device comprises N or more conductive layers (where N is a natural number of 2 or more) in which multiple coil elements are arranged in the transmission direction. The aforementioned N or more conductive layers function as waveguides for transmitting electromagnetic waves. The coil element comprises a first coil and a second coil. The second coil shares the same axis as the first coil and has the opposite winding direction. The transmission direction is the direction in which electromagnetic waves are transmitted through the waveguide when an alternating current flows through a circuit that includes a first circuit section in which a plurality of first coils are connected in series and a second circuit section in which a plurality of second coils are connected in series. The N or more conductive layers are arranged such that the positions of the coil elements in the transmission direction are offset from each other. Wireless power supply sheet.

2. In the wireless power supply sheet according to claim 1, The N or more conductive layers are arranged such that the positions of the coil elements in the transmission direction are offset from each other by 1 / N of the length of the coil elements in the transmission direction. Wireless power supply sheet.

3. In the wireless power supply sheet according to claim 1, The above N is 3. Wireless power supply sheet.

4. In the wireless power supply sheet according to claim 1, In the conductive layer, a plurality of the first coils are connected so that their winding directions are alternately opposite to each other to constitute the first circuit section, and a plurality of the second coils are connected so that their winding directions are alternately opposite to each other to constitute the second circuit section. Wireless power supply sheet.

5. In the wireless power supply sheet according to claim 1, The first circuit section is a series circuit in which the first coils of different conductive layers are connected sequentially. The second circuit section is a series circuit in which the second coils of different conductive layers are connected sequentially. Wireless power supply sheet.

6. In the wireless power supply sheet according to claim 1, The first coil and the second coil are formed from conductive wires coated with a dielectric material. The conductor of the first coil and the conductor of the second coil are in close contact. Wireless power supply sheet.

7. In the wireless power supply sheet according to claim 1, The first coil and the second coil are planar coils. Wireless power supply sheet.

8. A wireless power supply device, A wireless power supply sheet according to any one of claims 1 to 7 and a power supply unit are provided, The power supply unit is connected to one end of the wireless power supply sheet and supplies alternating current to the first circuit unit and the second circuit unit. Wireless power supply device.

9. In the wireless power supply device according to claim 8, Further comprising a reflection control unit, The reflection control unit is located at the end of the wireless power supply sheet opposite to the one end, and controls the reflection of electromagnetic waves transmitted to the wireless power supply sheet. The control described above cancels out the reflected electromagnetic wave reflected at the position of the receiving terminal when a receiving terminal exists between one end and the opposite end, due to the reflected wave from the reflection at the opposite end. Wireless power supply device.

10. In the wireless power supply device according to claim 9, The reflection control unit includes a circuit having an impedance corresponding to the circuit constants of the first coil and the second coil included in the conductive layer. Wireless power supply device.

11. A wireless power supply system, The wireless power supply device according to claim 8 and the power receiving terminal are provided, The power receiving terminal is equipped with a power receiving coil having a size of half a wavelength or less of the electromagnetic waves propagating within the wireless power supply sheet. Wireless power supply system.

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