Wireless power supply system device

Abstract

This wireless power supply system device comprises a ring-type electronic device and a power transmitter. The ring-type electronic device comprises: a wireless power receiving device configured with a power receiving coil; and an electronic functional circuit serving as a load and operating with output power from the wireless power receiving device. The power transmitter comprises a wireless power transmitting device configured with a power transmitting coil. The ring-type electronic device comprises a ring-type housing, a power receiving resonant capacitor, and a wireless power receiving circuit. The ring-type housing accommodates the wireless power receiving device and the load. The power receiving resonant capacitor is accommodated in the ring-type housing, and constitutes a power receiving resonant circuit using the power receiving coil. The wireless power receiving circuit is accommodated in the ring-type housing, rectifies alternating current received by the power receiving coil, converts the alternating current into a direct-current voltage, and supplies the direct-current voltage to the load. The power receiving coil is disposed along a circumferential direction on a part of the inner surface of the ring-type housing, and has a winding shape with an axis in a direction orthogonal to the circumferential surface. The power transmitter comprises a power transmitter housing, a power transmitting resonant capacitor, and the power transmitting resonant capacitor. The power transmitter housing has a cavity in which at least a part of the ring-type housing is accommodated. The power transmitting resonant capacitor is accommodated in the power transmitter housing, and constitutes a power transmitting resonant circuit using the power transmitting coil. The wireless power transmitting circuit is accommodated in the power transmitter housing, converts an input direct-current voltage into alternating current by means of a switching operation, and supplies the alternating current to the power transmitting coil. The power transmitting coil has an air-core shape and is disposed in a shape surrounding the cavity. The capacitance of the power transmitting resonant capacitor is set such that the input impedance, as viewed from the wireless power transmitting circuit toward the load side, is close to a minimum. At a switching frequency at which the switching operation is performed, even if there is a change in the coupling coefficient between the power transmitting coil and the power receiving coil due to a difference in the position or angle of installation of the ring-type electronic device accommodated in the cavity, an electromagnetic field resonance coupling with magnetic field strength at or higher than a predetermined level is formed.

Description

Wireless power supply system equipment

[0001] The present invention relates to a technology for wirelessly feeding power to a ring-type electronic device.

[0002] In recent years, people have become more health conscious, and as a result, the demand for wearable devices has expanded rapidly. Among these wearable devices, demand for ring-shaped electronic devices (smart rings) is on the rise due to their ease of use.

[0003] As for charging methods for ring-shaped electronic devices, in addition to wired charging, various wireless charging methods have been proposed, such as those shown in Patent Documents 1 to 3.

[0004] Japanese Patent Publication No. 2020-018380 Japanese Patent Publication No. 2017-085397 Chinese Patent Application Publication No. 218999717

[0005] However, in conventional configurations such as those shown in Patent Documents 1 to 3, although it is possible to arrange a ring-shaped electronic device with a certain degree of freedom in arrangement on a power transmitting device for wirelessly supplying power to the ring-shaped electronic device, it is difficult to supply power efficiently.

[0006] Therefore, an object of the present invention is to efficiently supply power while ensuring a predetermined degree of freedom in arranging ring-type electronic devices on a power transmitting device.

[0007] A wireless power supply system according to an embodiment of the present invention includes a ring-shaped electronic device and a power transmitter. The ring-shaped electronic device includes a wireless power receiver including a power receiving coil and an electronic function circuit that serves as a load operated by the output power of the wireless power receiver. The power transmitter includes a wireless power transmitter including a power transmitting coil.

[0008] The ring-shaped electronic device includes a ring-shaped housing, a power receiving resonant capacitor, and a wireless power receiving circuit. The ring-shaped housing accommodates a wireless power receiving device and a load. The power receiving resonant capacitor is housed in the ring-shaped housing and forms a power receiving resonant circuit using a power receiving coil. The wireless power receiving circuit is housed in the ring-shaped housing and rectifies AC current received by the power receiving coil, converts it into DC voltage, and supplies it to the load. The power receiving coil is arranged circumferentially on part of the inner surface of the ring-shaped housing and has a wound shape with its axis perpendicular to the circumferential surface.

[0009] The power transmitter includes a power transmitter housing, a power transmitter resonant capacitor, and a power transmitter resonant capacitor. The power transmitter housing has a cavity that accommodates at least a portion of the ring-shaped housing. The power transmitter resonant capacitor is housed in the power transmitter housing and forms a power transmitter resonant circuit using a power transmitter coil. The wireless power transmitter circuit is housed in the power transmitter housing and converts an input DC voltage into AC current by switching the power semiconductor, and supplies the AC current. The power transmitter coil has an air-core shape and is arranged in a shape that surrounds the cavity.

[0010] The capacitance of the power transmitting resonant capacitor is set so that the input impedance seen from the wireless power transmitting circuit toward the load is near a minimum. At the switching frequency at which switching operations are performed, electromagnetic field resonant coupling is formed at a predetermined magnetic field strength level or higher so that the load receives a predetermined amount of power, in response to changes in the coupling coefficient between the power transmitting coil and the power receiving coil due to differences in the installation position and angle of the ring-shaped electronic device housed in the cavity.

[0011] In this configuration, the ring-shaped electronic device is accommodated in the cavity of the power transmitter, and the receiving coil is positioned within a range where a predetermined electromagnetic field coupling can be achieved with the transmitting coil. The receiving coil and the power receiving resonant capacitor form a receiving resonant circuit, and the transmitting coil and the power transmitting resonant capacitor form a transmitting resonant circuit. Furthermore, the input impedance seen from the wireless power transmitting circuit as viewed from the load is near a minimum. In this way, by positioning the receiving coil and the power transmitting coil within a range where electromagnetic field coupling is possible and providing the power transmitting resonant circuit and the power receiving resonant circuit, the ring-shaped electronic device and the power transmitter form electromagnetic field resonant coupling of a predetermined magnetic field strength level or above.

[0012] According to this invention, it is possible to efficiently supply power while ensuring a predetermined degree of freedom in arranging the ring-type electronic device on the power transmitting device.

[0013] FIG. 1 is a diagram showing an example of a circuit configuration of a wireless power supply system according to a first embodiment of the present invention. FIGS. 2A and 2B are external perspective views of the wireless power supply system according to the first embodiment of the present invention. FIG. 3A is a plan view of the wireless power supply system according to the first embodiment of the present invention, and FIG. 3B is a side sectional view of the wireless power supply system according to the first embodiment of the present invention. FIG. 4A is a plan view of a power transmitter according to the first embodiment of the present invention, and FIG. 4B is a side sectional view of the power transmitter according to the first embodiment of the present invention. FIG. 5A is a plan view of a ring-shaped electronic device according to the first embodiment of the present invention, and FIG. 5B is a side sectional view of the ring-shaped electronic device according to the first embodiment of the present invention. FIG. 6 is a diagram showing an example of a state in which the ring-shaped electronic device is attached. FIGS. 7A and 7B are side sectional views of a wireless power supply system according to a second embodiment of the present invention. FIG. 8 is a side sectional view of a wireless power supply system according to a third embodiment of the present invention. FIG. 9 is a side sectional view of a wireless power supply system according to a fourth embodiment of the present invention.

[0014] First Embodiment A wireless power supply system according to a first embodiment of the present invention will be described with reference to the drawings.

[0015] (Circuit Configuration) Fig. 1 is a diagram showing an example of a circuit configuration of a wireless power supply system according to a first embodiment of the present invention. As shown in Fig. 1, the wireless power supply system 10 includes a power transmitter 20 and a ring-shaped electronic device 30.

[0016] (Power transmitter 20) The power transmitter 20 includes a high-side input terminal PinH, a low-side input terminal PinL, an input capacitor 22, a power transmission control circuit 23, a power transmission power conversion circuit 24, and a power transmission resonance circuit 25. The circuit formed by the power transmission control circuit 23 and the power transmission power conversion circuit 24 corresponds to the "wireless power transmission circuit" of the present application. Furthermore, in terms of the circuit, the power transmitter 20 corresponds to the "wireless power transmission device" of the present invention.

[0017] The high-side input terminal PinH is connected to the positive electrode of the DC power supply 21. The low-side input terminal PinL is connected to the negative electrode of the DC power supply 21. The low-side input terminal PinL is connected to the reference potential.

[0018] The input capacitor 22 is connected between the high-side input terminal PinH and the low-side input terminal PinLow.

[0019] The power transmission control circuit 23 is configured by an MCU etc. An output terminal of the power transmission control circuit 23 is connected to a control signal input terminal of the power transmission power conversion circuit 24 .

[0020] The transmission power conversion circuit 24 is configured with a plurality of switching elements. The input terminals of the transmission power conversion circuit 24 are connected to a high-side input terminal PinH and a low-side input terminal PinLow.

[0021] The power transmitting resonant circuit 25 is connected to the output terminal of the power transmitting power conversion circuit 24. The power transmitting resonant circuit 25 includes a power transmitting coil 251 and a power transmitting resonant capacitor 252. The power transmitting coil 251 and the power transmitting resonant capacitor 252 are connected in series to form a series resonant circuit.

[0022] (Ring-Type Electronic Device 30) The ring-type electronic device 30 includes an electronic function circuit 34 and a wireless power receiving device 39. The wireless power receiving device 39 includes a power receiving resonance circuit 31, a power receiving rectifier circuit 32, and a battery 33.

[0023] The power receiving resonance circuit 31 includes a parallel circuit of a power receiving coil 311 and a power receiving resonance capacitor 312. An output terminal of the power receiving resonance circuit 31 is connected to a power receiving rectifier circuit 32. An output terminal of the power receiving rectifier circuit 32 is connected to a battery 33. An electronic function circuit 34 is connected to the battery 33. The electronic function circuit 34 is configured by a sensor or the like that measures biometric information of the wearer who wears the ring-shaped electronic device 30. The electronic function circuit 34 may be an authentication IC or the like.

[0024] (Power Supply Operation) The power transmission control circuit 23 of the power transmitter 20 generates a switching control signal of a predetermined frequency (switching frequency) and outputs it to a plurality of switching elements through a control signal input terminal of the power transmission power conversion circuit 24 .

[0025] The switching elements are controlled to be turned on and off by a switching control signal, so that the switching elements perform a switching operation such that they are alternately turned on and off.

[0026] By this switching operation, the power transmission power conversion circuit 24 converts the input DC voltage (input DC current) into an AC voltage (AC current) and supplies this AC current to the power transmission coil 251 of the power transmission resonance circuit 25. The frequency of this AC current is determined by the switching frequency.

[0027] The power transmission coil 251 is excited by the supplied AC current and generates an AC magnetic field.

[0028] The power receiving coil 311 generates a power receiving AC current by linking with the AC magnetic field and outputs the power receiving AC current to the power receiving rectifier circuit 32 .

[0029] The power receiving rectifier circuit 32 rectifies and smoothes the received AC current and outputs a DC voltage (DC current). The battery 33 is charged by the output power (DC voltage, DC current) of the power receiving rectifier circuit 32. A voltage conversion circuit may be provided downstream of the power receiving rectifier circuit 32. The battery 33 may be charged by the output power of the voltage conversion circuit.

[0030] The electronic function circuit 34 is driven by the discharge voltage (discharge current) from the battery 33 and executes predetermined processing. Note that the electronic function circuit 34 may also be driven by the output power (DC voltage, DC current) of the power receiving rectifier circuit 32.

[0031] In this configuration, the wireless power supply system 10 further has the following features.

[0032] The resonant frequency of the power transmitting resonant circuit 25 is set to be approximately the same as the switching frequency. Here, the shape of the power transmitting coil 251 is limited by the shape of the housing of the power transmitter 20 (details will be described later), and is approximately determined. Therefore, by appropriately setting the capacitance of the power transmitting resonant capacitor 252, the resonant frequency of the power transmitting resonant circuit 25 can be set to be approximately the same as the switching frequency.

[0033] The resonant frequency of the power receiving resonant circuit 31 is set to be approximately the same as the switching frequency. Here, the shape of the power receiving coil 311 is limited by the shape of the housing of the ring-shaped electronic device 30 (details will be described later), and is approximately determined. Therefore, by appropriately setting the capacitance of the power receiving resonant capacitor 312, the resonant frequency of the power receiving resonant circuit 31 can be set to be approximately the same as the switching frequency.

[0034] In this way, since the power transmitting resonant frequency of the power transmitting resonant circuit 25 and the power receiving resonant frequency of the power receiving resonant circuit 31 are approximately the same as the switching frequency, the power transmitting coil 251 and the power receiving coil 311 form an electromagnetic field resonant coupling at the frequency of the alternating magnetic field that is approximately the same as the switching frequency.

[0035] This allows the distance over which the power transmitting coil 251 and the power receiving coil 311 can be electromagnetically coupled to be longer than that achieved with simple magnetic field coupling (magnetic field coupling without electromagnetic resonance coupling). Furthermore, when the distance between the power transmitting coil 251 and the power receiving coil 311 is the same, using electromagnetic field resonance coupling can achieve a magnetic field strength higher than that achieved with simple magnetic field coupling (magnetic field coupling without electromagnetic resonance coupling).

[0036] Furthermore, the capacitance of the power transmitting resonant capacitor 252 is set so that the input impedance when viewed from the output terminal of the power transmitting power conversion circuit 24 to the electronic function circuit 34 side (the load side connected to the wireless power receiving device 39) is close to a minimum at the switching frequency. This makes it possible to achieve a higher magnetic field strength in the electromagnetic field resonance coupling between the power transmitting coil 251 and the power receiving coil 311. Note that the load for this input impedance preferably further includes the charging state of the battery 33 included in the wireless power receiving device 39.

[0037] Furthermore, the frequency characteristics of the input impedance change depending on the coupling coefficient between the power transmitting coil 251 and the power receiving coil 311. The coupling coefficient between the power transmitting coil 251 and the power receiving coil 311 depends on the state in which the ring-shaped electronic device 30 (described later) is attached to the power transmitter 20.

[0038] Therefore, it is preferable to set the capacitance of the power transmitting resonant capacitor 252 so that the input impedance is close to a minimum at the switching frequency, further taking into consideration the coupling coefficient.

[0039] For example, a range of possible coupling coefficients is set in advance based on the shapes of the housings of the ring-type electronic device 30 and the power transmitter 20. A representative coupling coefficient is set within this range of coupling coefficients. The representative coupling coefficient corresponds to the coupling coefficient when the ring-type electronic device 30 is attached to the power transmitter 20 in the optimal position and posture, for example.

[0040] The capacitance of the power transmitting resonant capacitor 252 is set using a representative coupling coefficient so that the input impedance at the switching frequency is minimized.

[0041] As a result, the transmitting coil 251 and the receiving coil 311 can form electromagnetic resonance coupling at a predetermined magnetic field strength level or higher at the representative coupling coefficient. Furthermore, electromagnetic resonance coupling at a predetermined magnetic field strength level or higher can be formed even within a predetermined range of coupling coefficients that are close to the representative coupling coefficient. As a result, the wireless power transfer system 10 can achieve efficient power transfer from the transmitting coil 251 to the receiving coil 311 even if the coupling coefficient changes within a predetermined range.

[0042] As one mode for realizing the above-described efficient power supply, the power transmitter 20 and the ring-shaped electronic device 30 of the wireless power supply system 10 have the following structure.

[0043] 2(A) and 2(B) are external perspective views of the wireless power supply system according to the first embodiment. Fig. 2(A) shows a state in which the ring-shaped electronic device is detached from the power transmitter, and Fig. 2(B) shows a state in which the ring-shaped electronic device is attached to the power transmitter. Fig. 3(A) is a plan view of the wireless power supply system according to the first embodiment of the present invention, and Fig. 3(B) is a side cross-sectional view of the wireless power supply system according to the first embodiment of the present invention. Fig. 4(A) is a plan view of the power transmitter according to the first embodiment of the present invention, and Fig. 4(B) is a side cross-sectional view of the power transmitter according to the first embodiment of the present invention. Fig. 5(A) is a plan view of the ring-shaped electronic device according to the first embodiment of the present invention, and Fig. 5(B) is a side cross-sectional view of the ring-shaped electronic device according to the first embodiment of the present invention.

[0044] In addition, in each drawing of each embodiment including this embodiment, in order to make the drawings easier to see and understand the configuration, the illustration of some components is omitted and simplified. Also, each cross-sectional view is not a cross-sectional view cut along a plane, but a cross-sectional view seen so as to clarify the configuration.

[0045] (Power transmitter 20) As shown in Figures 2(A), 2(B), 3(A), 3(B), 4(A), and 4(B), the power transmitter 20 includes a power transmitter housing 200, a magnetic sheet 259, and a circuit board 291.

[0046] The power transmitter housing 200 has a substantially rectangular parallelepiped shape. However, the external shape of the power transmitter housing 200 is not limited to a substantially rectangular parallelepiped shape. The power transmitter housing 200 includes a top surface 201, a bottom surface 202, and a plurality of side surfaces 203. The top surface 201, the bottom surface 202, and the plurality of side surfaces 203 are plate-shaped. The top surface 201 and the bottom surface 202 are spaced apart in the height direction of the power transmitter housing 200 and face each other. The plurality of side surfaces 203 are arranged along the outer peripheries of the top surface 201 and the bottom surface 202 and are physically connected to the top surface 201 and the bottom surface 202. As a result, the power transmitter housing 200 forms an internal space surrounded by the top surface 201, the bottom surface 202, and the plurality of side surfaces 203.

[0047] The power transmitter housing 200 is provided with a PORT 21. The PORT 21 constitutes a high-side input terminal PinH and a low-side input terminal PinL. The PORT 21 is formed, for example, with a USB terminal. When a USB terminal is used, the PORT 21 can be used as a data communication port for communicating biological information of the wearer measured by a ring-shaped electronic device 30 (described later) to the outside through the power transmitter 20.

[0048] The power transmitter housing 200 includes a cavity CAV recessed from the top surface 201 toward the internal space. The cavity CAV includes a plurality of cavity side surfaces 204 extending in the height direction of the power transmitter housing 200, and a cavity bottom surface 205 forming the bottom surface of the cavity CAV and substantially perpendicular to the height direction of the power transmitter housing 200. One ends of the plurality of cavity side surfaces 204 in the height direction are physically connected to the top surface 201. The other ends of the plurality of cavity side surfaces 204 in the height direction are physically connected to the cavity bottom surface 205. As a result, the cavity CAV opens to the outside of the power transmitter housing 200 from the top surface 201 side of the power transmitter housing 200, forming a space having a substantially rectangular parallelepiped shape.

[0049] The power transmitter housing 200 is made of a material having magnetic permeability. In this case, it is sufficient that at least the top surface 201 and the plurality of cavity side surfaces 204 of the power transmitter housing 200 are made of a material having magnetic permeability.

[0050] The circuit board 291 is formed by forming a predetermined conductor pattern on a plate-shaped insulating base material. A power transmission coil 251 is formed on a first surface of the circuit board 291. The power transmission coil 251 is formed of a wound linear conductor and has an air-core shape with an opening OP251 inside the wound shape. The power transmission coil 251 has a rectangular shape in a planar view, which is approximately similar to the shape of the cavity CAV in a planar view. The shape of the opening OP251 is larger than the shape of the cavity CAV in a planar view and is larger than the opening OP291 of the circuit board 291.

[0051] A power transmitting resonant capacitor 252 and a power transmitting device 292 are mounted on a first surface of the circuit board 291. The power transmitting resonant capacitor 252 is formed, for example, by a mount-type chip component. The power transmitting device 292 is formed by a mount-type electronic component such as an IC. The power transmitting device 292 constitutes the power transmitting control circuit 23 and the power transmitting power conversion circuit 24 in terms of circuits. Although not shown, the input capacitor 22 and other components of the power transmitter 20 are mounted or formed on the circuit board 291. In this way, the circuit board 291 realizes the electrical functions of the power transmitter 20.

[0052] An opening OP291 is formed in the circuit board 291. The opening OP291 has a shape that penetrates the circuit board 291 from the first surface side to the second surface (the surface opposite the first surface). The planar shape of the opening OP291 is larger than the planar shape of the cavity CAV of the power transmitter housing 200.

[0053] The circuit board 291 is arranged in the internal space of the power transmitter housing 200 so that the first surface faces the top surface 201 of the power transmitter housing 200 and the second surface faces the bottom surface 202 of the power transmitter housing 200 .

[0054] The circuit board 291 is attached to the power transmitter housing 200 so that the cavity CAV is housed in the opening OP291 in a plan view. As a result, the power transmitting coil 251 is arranged in the power transmitter housing 200 in a shape that surrounds the cavity CAV in a plan view.

[0055] The circuit board 291 is disposed near the top surface 201. More specifically, the circuit board 291 is disposed such that the power transmitting coil 251 is positioned closer to the top surface 201 than the cavity bottom surface 205 in the height direction of the power transmitter housing 200.

[0056] Furthermore, the circuit board 291 is positioned so that, when the ring-shaped electronic device 30 is housed in the cavity CAV of the power transmitter 20, the position of the power transmitting coil 251 and the position of the power receiving coil 311 overlap in the height direction of the power transmitter 20.

[0057] The magnetic material sheet 259 is disposed between the bottom surface 202 of the power transmitter housing 200 and the cavity bottom surface 205. The magnetic material sheet 259 is disposed so as to overlap at least the opening OP251 of the power transmitting coil 251 in a plan view. The magnetic material sheet 259 preferably overlaps the entire power transmitting coil 251 in a plan view, and more preferably has a shape that overlaps the entire power transmitting coil 251 in a plan view and extends over a larger area than the power transmitting coil 251. By disposing the magnetic material sheet 259 in this manner, undesired leakage of the magnetic field toward the bottom side of the power transmitter 20 can be suppressed, and the magnetic field strength in the cavity CAV can be increased.

[0058] (Ring-Shaped Electronic Device 30) As shown in Figures 2(A), 2(B), 3(A), 3(B), 5(A), and 5(B), the ring-shaped electronic device 30 includes a ring-shaped housing 300. The ring-shaped housing 300 includes a cylindrical outer peripheral portion 301 and a cylindrical inner peripheral portion 302. The outer peripheral portion 301 and the inner peripheral portion 302 have a predetermined thickness. The diameter of the inner peripheral portion 302 is smaller than the diameter of the outer peripheral portion 301. The inner peripheral portion 302 is disposed on the central side of the outer peripheral portion 301. The outer peripheral portion 301 and the inner peripheral portion 302 are physically connected by a pair of annular side walls. As a result, the ring-shaped housing 300 forms a cylindrical internal space surrounded by the outer peripheral portion 301, the inner peripheral portion 302, and the pair of side walls. The ring-shaped housing 300 has a through-hole HL located inside the inner periphery 302 (toward the center where the ring-shaped housing 300 appears to be annular).

[0059] 6 is a diagram showing an example of a state in which the ring-shaped electronic device 30 is worn. As shown in FIG. 6, the user of the ring-shaped electronic device 30 wears the ring-shaped electronic device 30 by inserting a finger into the through-hole HL of the ring-shaped housing 300.

[0060] The power receiving coil 311 is configured, for example, by forming a linear conductor pattern on an insulating flexible substrate. The power receiving coil 311 is a wound linear conductor pattern and has an air-core shape with an opening OP311 inside the wound shape. The power receiving coil 311 is approximately rectangular in plan view and has a long side and a short side.

[0061] The power receiving coil 311 is arranged along the circumferential direction on a part of the inner surface of the outer circumferential portion 301 of the ring-shaped housing 300. The power receiving coil 311 is arranged so that the long side direction substantially coincides with the circumferential direction. The power receiving coil 311 is arranged so that the axial direction of the winding shape substantially coincides with the direction perpendicular to the circumferential surface.

[0062] Here, the part in the circumferential direction refers to a range of a predetermined angle α (for example, an angle from approximately 45° to approximately 135°) with respect to a center PO30 (the center PO30 of the ring-shaped housing 300) at which the ring-shaped housing 300 appears to be annular. In relation to the power transmitter 20, this angle α range is preferably set to be larger than an angle θ (see FIG. 3B ) determined by a pair of edge portions RL with which the ring-shaped housing 300 contacts the opening of the cavity CAV of the power transmitter housing 200, with respect to the center PO30 of the ring-shaped housing 300 as a reference, when the ring-shaped electronic device 30 is placed in an appropriate position with respect to the power transmitter 20.

[0063] The circuit board 392 is configured, for example, by forming a predetermined conductor pattern on a plate-shaped insulating substrate. The conductor pattern of the circuit board 392 is electrically and physically connected to the power receiving coil 311. The power receiving rectifier circuit 32 is configured on the circuit board 392 in a circuit manner. Although not shown, electronic components that configure the battery 33 and the electronic function circuit 34 are also mounted on the circuit board 392. As a result, the circuit board 392 realizes the electrical functions of the ring-shaped electronic device 30 and the wireless power receiving device 39 except for the power receiving coil 311.

[0064] In addition, if the electronic function circuit 34 is an optical sensor or the like that measures the wearer's biometric information, the optical sensor is positioned on the inner periphery 302 side of the ring-shaped housing 300 relative to the receiving coil 311, and is positioned so that it can transmit and receive light inside the inner periphery 302.

[0065] (State in which the ring-shaped electronic device 30 is accommodated in the power transmitter 20) As shown in Figures 2(B), 3(A), and 3(B), the ring-shaped electronic device 30 is placed in the power transmitter 20 so that a portion of the ring-shaped housing 300 is accommodated in the cavity CAV.

[0066] The cavity CAV has a rectangular shape in a plan view, and the length Lcav in the first direction is determined based on the diameter φ of the ring-shaped housing 300. The length in the second direction is set based on the width of the ring-shaped housing 300 (the length in the axial direction of the cylinder). The length in the second direction is the width of the ring-shaped housing 300 plus a placement error.

[0067] The length Lcav in the first direction is shorter than the diameter φ of the ring-shaped housing 300. The length Lcav in the first direction is longer than the length of the long side of the receiving coil 311, more preferably longer than the length of the opening OP311 of the receiving coil 311 in the long side direction.

[0068] The ring-shaped housing 300 is housed in the cavity CAV so that the width direction of the ring-shaped housing 300 and the second direction of the cavity CAV are substantially aligned.

[0069] At this time, since the length Lcav of the cavity CAV in the first direction is shorter than the diameter of the ring-shaped housing 300, the ring-shaped housing 300 comes into contact with the edge portions RL at both ends in the first direction of the opening of the cavity CAV in the power transmitter housing 200. As a result, the ring-shaped housing 300 is held and positioned in the power transmitter housing 200 with a portion of the ring-shaped housing 300 housed in the cavity CAV.

[0070] The depth of the cavity CAV is such that, when the outer periphery 301 of the ring-shaped housing 300 is in contact with the edge portion RL of the cavity CAV, the outer periphery 301 of the ring-shaped housing 300 does not contact the surface of the cavity bottom portion 205 (the bottom surface of the cavity CAV). This allows the ring-shaped housing 300 to be held only by the pair of edge portions RL of the power transmitter housing 200. This prevents the ring-shaped housing 300 from contacting the bottom surface of the cavity CAV and undesirably rotating in the circumferential direction. As a result, the ring-shaped electronic device 30 can be maintained in a state where it is placed relative to the power transmitter 20.

[0071] In such a configuration, the ring-shaped electronic device 30 is placed on the power transmitter 20 so that the surface of the ring-shaped housing 300 on which the power receiving coil 311 is placed faces the bottom surface of the cavity CAV.

[0072] As a result, in a plan view, the power receiving coil 311 overlaps with the power transmitting coil 251. Furthermore, the opening OP311 of the power receiving coil 311 overlaps with the opening OP251 of the power transmitting coil 251. As a result, the power receiving coil 311 and the power transmitting coil 251 can achieve electromagnetic field coupling with a high coupling coefficient, and can form electromagnetic field resonance coupling with a high magnetic field strength.

[0073] Furthermore, the power receiving coil 311 is curved in side view and is disposed so as to cross in the height direction the opening OP251 of the power transmitting coil 251. This allows the power receiving coil 311 and the power transmitting coil 251 to achieve electromagnetic field coupling with an even higher coupling coefficient, and to form electromagnetic field resonance coupling with even higher magnetic field strength.

[0074] In the above arrangement, the most appropriate orientation of the ring-shaped electronic device 30 is one in which, in a plan view, the center of the power receiving coil 311 coincides with the center of the power transmitting coil 251. By arranging them in this manner, the power receiving coil 311 and the power transmitting coil 251 can achieve electromagnetic field coupling with the highest coupling coefficient, and can form electromagnetic field resonance coupling with the highest magnetic field strength.

[0075] However, the wearer places the ring-shaped electronic device 30 on the power transmitter 20. Therefore, the ring-shaped housing 300 may be placed in the cavity CAV in a state where it is slightly rotated in the circumferential direction relative to the above-mentioned proper posture. In this case, the coupling coefficient between the power transmitting coil 251 and the power receiving coil 311 changes.

[0076] However, as shown in the circuit configuration described above, the capacitance of the power transmitting resonant capacitor 252 is set so that the input impedance seen from the output terminal of the power transmitting power conversion circuit 24 to the electronic function circuit 34 side (the load side connected to the wireless power receiving device 39) is close to a minimum at the switching frequency. Therefore, even if the position of the power receiving coil 311 relative to the power transmitting coil 251 shifts due to rotation of the ring-shaped housing 300, a predetermined high magnetic field strength can be maintained.

[0077] In particular, in a plan view, the length of the long side of the power receiving coil 311 is longer than the length Lcav of the cavity CAV in the first direction, which suppresses changes in the overlapping area between the opening OP311 of the power receiving coil 311 and the opening OP251 of the power transmitting coil 251 due to rotation. Therefore, the power receiving coil 311 and the power transmitting coil 251 can maintain a predetermined high magnetic field intensity.

[0078] In this way, the wireless power supply system 10 can perform efficient power supply by forming electromagnetic field resonance coupling with a predetermined high magnetic field strength even if the posture of the ring-shaped electronic device 30 changes. As a result, the wireless power supply system 10 can perform efficient power supply while ensuring a predetermined degree of freedom in the placement of the ring-shaped electronic device 30 relative to the power transmitter 20.

[0079] The ring-shaped electronic device 30 has a mark 309 on the ring-shaped housing 300 on the opposite side from the position where the power receiving coil 311 is disposed, which allows the ring-shaped electronic device 30 to be easily placed in the above-mentioned orientation relative to the power transmitter 20. Furthermore, the mark 309 can also be used to confirm the orientation when putting the ring-shaped electronic device 30 on the wearer's finger. This allows the wearer to easily put the ring-shaped electronic device 30 in a desired orientation. As a result, for example, if the electronic function circuit 34 is a sensor, it can accurately measure the wearer's biological information, etc.

[0080] The ring-shaped electronic device 30 is not limited to the mark 309, and may have a pattern, irregularities, or the like as long as the position of the power receiving coil 311 can be identified.

[0081] Furthermore, in conventional configurations, it was extremely difficult to efficiently supply power to multiple ring diameter sizes using a common power transmission device, especially when the ring diameter size of a ring-shaped electronic device was changed depending on the user and multiple ring diameter sizes were provided.

[0082] However, by using the configuration of this embodiment, even if the ring diameter size of the ring-shaped electronic device is changed depending on the user and multiple ring diameter sizes are provided, efficient power supply can be performed for multiple ring diameter sizes using a common power transmission device.

[0083] Second Embodiment A wireless power supply system according to a second embodiment of the present invention will be described with reference to the drawings. FIGS. 7A and 7B are side cross-sectional views of the wireless power supply system according to the second embodiment of the present invention. A wireless power supply system 10A shown in FIG. 7A and a wireless power supply system 10AX shown in FIG. 7B differ from the wireless power supply system 10 according to the first embodiment in the configuration of a power transmitter 20A and the configuration of a power transmitter 20AX, respectively. Other configurations of the wireless power supply systems 10A and 10AX are similar to those of the wireless power supply system 10, and a description of similar parts will be omitted. Further, only the parts of the power transmitter 20A and the power transmitter 20AX that differ from the power transmitter 20 will be described below. The power transmitter 20A and the power transmitter 20AX are similar to the power transmitter 20 except for the parts described below, and a description of similar parts will be omitted.

[0084] 7A, the power transmitter 20A includes a circuit board 291A. The circuit board 291A includes a power transmitting coil board 2911, an electronic function circuit board 2912, and a connection board 2913.

[0085] The power transmitting coil 251 is formed on the power transmitting coil substrate 2911. The power transmitting coil substrate 2911 includes an opening OP291. The power transmitting coil substrate 2911 is disposed in the power transmitter housing 200 so that the cavity CAV is located within the opening OP291.

[0086] The electronic function circuit board 2912 is mounted with the power transmitting resonant capacitor 252 and the power transmitting device 292. The electronic function circuit board 2912 is disposed at a position overlapping the power transmitting coil 251 in plan view. The electronic function circuit board 2912 is disposed between the bottom surface 202 of the power transmitter housing 200 and the cavity bottom surface 205. More specifically, the electronic function circuit board 2912 is disposed between the magnetic sheet 259 and the cavity bottom surface 205.

[0087] The connection substrate 2913 is formed of, for example, a flexible substrate. The connection substrate 2913 electrically and physically connects the power transmitting coil substrate 2911 and the electronic function circuit substrate 2912.

[0088] With this configuration, the wireless power supply system 10A, like the wireless power supply system 10, can efficiently supply power while ensuring a predetermined degree of freedom in the placement of the ring-shaped electronic device 30 on the power transmitter 20.

[0089] Furthermore, in the power transmitter 20A, the power transmitting coil 251, the power transmitting resonant capacitor 252, and the power transmitting device 292 are not arranged side by side on one circuit board, so the planar shape of the power transmitter 20A can be made small.

[0090] As shown in FIG. 7B, the positional relationship between the magnetic sheet 259 and the electronic function circuit board 2912 of the power transmitter 20AX is reversed compared to the power transmitter 20A, but the other configurations are the same as those of the power transmitter 20A.

[0091] Specifically, the magnetic sheet 259 is disposed between the electronic function circuit board 2912 and the cavity bottom portion 205 .

[0092] As a result, the magnetic field leaking to the bottom side of the cavity CAV is stopped by the magnetic sheet 259 , and the leakage magnetic field can be prevented from reaching the electronic function circuit board 2912 .

[0093] [Third Embodiment] A wireless power supply system according to a third embodiment of the present invention will be described with reference to the drawings. Fig. 8 is a side cross-sectional view of the wireless power supply system according to the third embodiment of the present invention. The wireless power supply system 10B shown in Fig. 8 differs from the wireless power supply system 10 according to the first embodiment in the configuration of a power transmitter 20B. The other configuration of the wireless power supply system 10B is the same as that of the wireless power supply system 10, and a description of similar parts will be omitted. In the following, only the parts of the power transmitter 20B that are different from the power transmitter 20 will be described; the power transmitter 20B is the same as the power transmitter 20 except for the parts described below, and a description of similar parts will be omitted.

[0094] 8, the power transmitter 20B includes a circuit board 291B. The circuit board 291B is a multilayer circuit board in which multiple insulating base materials are stacked. The power transmitting coils 251 are formed on multiple layers, and the power transmitting coils 251 formed on the multiple layers are connected in series by interlayer connecting conductors (not shown).

[0095] The circuit board 291B has an opening OP291 that penetrates between both end faces in the stacking direction. The cavity CAV is disposed in the opening OP291.

[0096] With this configuration, the power transmitter 20B can further increase the magnetic field strength generated by the power transmitting coil 251. As a result, the wireless power feed system 10B can form electromagnetic field resonance coupling with a higher magnetic field strength while ensuring a certain degree of freedom in the placement of the ring-shaped electronic device 30 on the power transmitter 20, thereby enabling more efficient power feed.

[0097] [Fourth Embodiment] A wireless power supply system according to a fourth embodiment of the present invention will be described with reference to the drawings. Fig. 9 is a side cross-sectional view of the wireless power supply system according to the fourth embodiment of the present invention. The wireless power supply system 10C shown in Fig. 9 differs from the wireless power supply system 10A according to the second embodiment in the configuration of the power transmitter 20C. The other configuration of the wireless power supply system 10C is the same as that of the wireless power supply system 10A, and a description of similar parts will be omitted. In the following, only the parts of the power transmitter 20C that are different from the power transmitter 20A will be described; other than the parts of the power transmitter 20C that will be described below, the power transmitter 20C is the same as the power transmitter 20A, and a description of similar parts will be omitted.

[0098] The circuit board 291C includes a power transmitting coil board 2911C, an electronic function circuit board 2912, and a connection board 2913.

[0099] The power transmitting coil substrate 2911C is curved in side view. More specifically, the power transmitting coil substrate 2911C is curved so that the central portion in the long side direction is located closer to the cavity bottom (cavity bottom portion 205) than both end portions.

[0100] This configuration further increases the area of ​​the power receiving coil 311 projected onto the surface on which the power transmitting coil 251 is formed. Therefore, the power transmitting coil 251 and the power receiving coil 311 can form electromagnetic field resonance coupling with even higher magnetic field strength.

[0101] As a result, the wireless power supply system 10C can form electromagnetic field resonance coupling with a higher magnetic field strength while ensuring a certain degree of freedom in the placement of the ring-shaped electronic device 30 relative to the power transmitter 20, thereby enabling more efficient power supply.

[0102] In the above-described embodiments, the ring-shaped electronic device 30 has been described with respect to one diameter as an example. However, as long as the above-described relationships can be ensured among the diameter φ of the ring-shaped electronic device 30, the length Lcav of the cavity CAV in the long side direction, and the depth of the cavity CAV, the diameter φ of the ring-shaped electronic device 30, i.e., the size of the ring-shaped electronic device 30, can be varied.

[0103] Furthermore, the configurations of the above-described embodiments can be combined as appropriate, and effects according to each combination can be achieved.

[0104] <1> A wireless power supply system apparatus comprising: a ring-shaped electronic device including a wireless power receiving device including a power receiving coil and an electronic function circuit serving as a load operated by output power of the wireless power receiving device; and a power transmitter including a wireless power transmitting device including a power transmitting coil, wherein the ring-shaped electronic device comprises: a ring-shaped housing that accommodates the wireless power receiving device and the load; a power receiving resonance capacitor that is accommodated in the ring-shaped housing and configures a power receiving resonance circuit using the power receiving coil; and a wireless power receiving circuit that is accommodated in the ring-shaped housing and rectifies and smooths AC current received by the power receiving coil, converts it into a DC voltage, and supplies the DC voltage to the load, wherein the power receiving coil is disposed along the circumferential direction on a part of the inner surface of the ring-shaped housing and has a wound shape with an axis perpendicular to the circumferential surface, and the power transmitter comprises: a power transmitter housing having a cavity that accommodates at least a part of the ring-shaped housing; and a power transmitting resonance capacitor that is accommodated in the power transmitter housing and configures a power transmitting resonance circuit using the power transmitting coil. a wireless power transmission circuit housed in the power transmitter housing, which converts an input DC voltage into an AC current flowing through the power transmission coil by switching operation of a power semiconductor and supplies the AC current; wherein the power transmission coil has an air-core shape and is arranged in a shape surrounding the cavity; and the power transmission resonant capacitor has a capacitance set so that the input impedance seen from the wireless power transmission circuit to the load side is close to a minimum, and at a switching frequency at which the switching operation is performed, forms an electromagnetic field resonant coupling of a predetermined magnetic field strength level or more so that the load receives a predetermined power in response to changes in the coupling coefficient between the power transmission coil and the power receiving coil due to differences in the installation position and angle of the ring-shaped electronic device housed in the cavity.

[0105] <2> The wireless power supply system apparatus according to <1>, wherein the ring-shaped electronic device receives power from the power transmitter in a state where at least a portion of the power receiving coil is disposed in a space defined by an air core of the power transmitting coil.

[0106] <3> The wireless power supply system apparatus according to <1> or <2>, wherein the power transmitter includes a circuit board on which the power transmission coil is formed on an insulating base material.

[0107] <4> The wireless power supply system apparatus according to <3>, wherein the circuit board is a multilayer circuit board in which the insulating base material is laminated in a plurality of layers, and the power transmission coil is formed on a plurality of layers, and the power transmission coils formed on the plurality of layers are connected in series by interlayer connecting conductors.

[0108] <5> The wireless power supply system apparatus according to <3> or <4>, wherein the power transmission coil has a shape in which a central portion thereof is located closer to a bottom surface of the cavity than both end portions thereof in a side view.

[0109] <6> The wireless power supply system apparatus according to any one of <1> to <5>, wherein a distance between both ends of the opening of the cavity in a side view is smaller than a diameter of the ring-shaped housing.

[0110] <7> The wireless power supply system device according to any one of <1> to <6>, wherein the cavity has a shape such that a lowermost portion of the ring-shaped housing does not contact a bottom surface of the cavity when the outer peripheral surface of the ring-shaped housing is in contact with both ends of the opening of the cavity in a side view.

[0111] <8> The wireless power supply system apparatus according to any one of <1> to <7>, wherein the ring-shaped housing has a mark indicating an arrangement position of the power receiving coil.

[0112] <9> The wireless power supply system apparatus according to any one of <1> to <8>, wherein the load includes an optical sensor arranged on an inner surface inside the ring-shaped housing, and the power receiving coil is arranged on an outer surface of the ring-shaped housing at a position where the optical sensor is arranged.

[0113] <10> The wireless power supply system apparatus according to any one of <1> to <9>, wherein the frequency of the switching operation is in the 6.78 MHz band or the 13.56 MHz band of the ISM band.

[0114] 10, 10A, 10AX, 10B, 10C: Wireless power supply system 20, 20A, 20AX, 20B, 20C: Power transmitter 21: DC power supply 22: Input capacitor 23: Power transmission control circuit 24: Power transmission power conversion circuit 25: Power transmission resonance circuit 30: Ring-shaped electronic device 31: Power reception resonance circuit 32: Power reception rectification circuit 33: Battery 34: Electronic function circuit 39: Wireless power receiver 200: Power transmitter housing 201: Top surface 202: Bottom surface 203: Side surface 204: Cavity side surface 205: Cavity bottom surface 251: Power transmission coil 252: Power transmission resonance capacitor 259: Magnetic sheet 291, 291A, 291B, 291C: Circuit board 292: Power transmission device 300: Ring-shaped housing 301: Outer periphery 302: Inner periphery 309: Mark 311: Receiving coil 312: Receiving resonance capacitor 392: Circuit board 2911, 2911C: Transmitting coil board 2912: Electronic function circuit board 2913: Connection board CAV: Cavity HL: Through hole OP251: Opening OP291: Opening OP311: Opening PO30: Center PinH: Hi-side input terminal PinL: Low-side input terminal RL: Edge part

Claims

1. A wireless power supply system apparatus comprising: a ring-shaped electronic device having a wireless power receiving device configured with a power receiving coil and an electronic function circuit that serves as a load operated by the output power of the wireless power receiving device; and a power transmitter having a wireless power transmitting device configured with a power transmitting coil, wherein the ring-shaped electronic device comprises: a ring-shaped housing that accommodates the wireless power receiving device and the load; a power receiving resonance capacitor that is accommodated in the ring-shaped housing and forms a power receiving resonance circuit using the power receiving coil; and a wireless power receiving circuit that is accommodated in the ring-shaped housing and rectifies and smooths AC current received by the power receiving coil, converts it into a DC voltage, and supplies the DC voltage to the load, wherein the power receiving coil is disposed along the circumferential direction on a part of the inner surface of the ring-shaped housing and has a wound shape with an axis perpendicular to the circumferential surface, and the power transmitter comprises: a power transmitter housing having a cavity that accommodates at least a part of the ring-shaped housing; and a power transmitting resonance capacitor that is accommodated in the power transmitter housing and forms a power transmitting resonance circuit using the power transmitting coil. a wireless power transmission circuit housed in the power transmitter housing, which converts an input DC voltage into an AC current flowing through the power transmission coil by switching operation of a power semiconductor and supplies the AC current; wherein the power transmission coil has an air-core shape and is arranged in a shape surrounding the cavity; and the power transmission resonant capacitor has a capacitance set so that the input impedance seen from the wireless power transmission circuit to the load side is close to a minimum, and at a switching frequency at which the switching operation is performed, forms an electromagnetic field resonant coupling of a predetermined magnetic field strength level or more so that the load receives a predetermined power in response to changes in the coupling coefficient between the power transmission coil and the power receiving coil due to differences in the installation position and angle of the ring-shaped electronic device housed in the cavity.

2. The wireless power supply system apparatus according to claim 1, wherein the ring-shaped electronic device receives power from the power transmitter with at least a portion of the power receiving coil disposed within the space defined by the air core of the power transmitting coil.

3. The wireless power supply system device according to claim 1 or 2, wherein the power transmitter comprises a circuit board having an insulating substrate on which the power transmission coil is formed.

4. The wireless power supply system device according to claim 3, wherein the circuit board is a multilayer circuit board in which the insulating base material is laminated in multiple layers, the power transmission coil is formed on multiple layers, and the power transmission coils formed on multiple layers are connected in series by interlayer connecting conductors.

5. The wireless power supply system device according to claim 3 or 4, wherein the power transmission coil has a shape such that a central portion thereof is located closer to the bottom surface of the cavity than both end portions when viewed from the side.

6. A wireless power supply system device according to any one of claims 1 to 5, wherein the distance between both ends of the opening of the cavity when viewed from the side is smaller than the diameter of the ring-shaped housing.

7. A wireless power supply system device according to any one of claims 1 to 6, wherein the cavity is shaped so that the bottom of the ring-shaped housing does not come into contact with the bottom surface of the cavity when the outer peripheral surface of the ring-shaped housing is in contact with both ends of the opening of the cavity as viewed from the side.

8. The wireless power supply system device according to any one of claims 1 to 7, wherein the ring-shaped housing has a mark indicating the placement position of the power receiving coil.

9. A wireless power supply system device according to any one of claims 1 to 8, wherein the load includes an optical sensor arranged on the inner surface inside the ring-shaped housing, and the receiving coil is arranged on the outer surface of the ring-shaped housing at a position where the optical sensor is arranged.

10. The wireless power supply system device according to any one of claims 1 to 9, wherein the frequency of the switching operation is in the 6.78 MHz band or the 13.56 MHz band of the ISM band.

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