PATENT DOCUMENT

Publication Number: US-11611239-B2
Application Number: US-202117546808-A
Country: US
Kind Code: B2

Title: Wireless charging system with solenoids

Abstract:
A wireless power transmitting device may transmit wireless power signals to a wireless power receiving device. The wireless power receiving device may have a housing. A display may be mounted in the housing on a front face of the device. A rear housing wall on a rear face of the device may be provided with a wireless power receiving solenoid. The solenoid may have a linear strip shape that extends along a longitudinal axis. The longitudinal axis may extend perpendicularly to a wrist strap coupled to the housing. The wireless power receiving solenoid may have opposing first and second ends. The wireless power transmitting device may have a wireless power transmitting solenoid with opposing first and second ends that are configured to transmit the wireless power signals respectively to the first and second ends of the wireless power receiving device when the wireless power receiving solenoid is within the cradle.

Claims:
What is claimed is: 
     
       1. A wireless power receiving device having opposing first and second faces, wherein the wireless power receiving device is configured to receive wireless power signals from a wireless power transmitting device, the wireless power receiving device comprising:
 a housing having a housing wall at the first face; 
 a display mounted to the housing at the second face; and 
 a power receiving solenoid that has a solenoid core and that is configured to receive the wireless power signals from the wireless power transmitting device, wherein the solenoid core has a first strip portion extending along a first longitudinal axis, a second strip portion extending along a second longitudinal axis parallel to the first longitudinal axis, and a curved portion that extends from the first strip portion to the second strip portion, the power receiving solenoid further comprising windings of wire wrapped around the curved portion of the solenoid core. 
 
     
     
       2. The wireless power receiving device of  claim 1 , wherein the curved portion runs along the housing wall. 
     
     
       3. The wireless power receiving device of  claim 1 , wherein the solenoid core comprises ferrite. 
     
     
       4. The wireless power receiving device of  claim 1 , wherein the housing is configured to receive a wrist strap. 
     
     
       5. The wireless power receiving device of  claim 1 , wherein at least some of the solenoid core is free from windings of wire. 
     
     
       6. The wireless power receiving device of  claim 1 , wherein the windings of wire comprise a conductive wire selected from the group consisting of: a metal strand with a dielectric coating, a metal strand with a magnetic coating, a metal strand with a rectangular cross-sectional shape, and a conductive wire formed from multiple intertwined metal strands. 
     
     
       7. The wireless power receiving device of  claim 1 , further comprising:
 a battery; and 
 wireless power receiving circuitry coupled to the windings of wire and configured to charge the battery using the wireless power signals received by the power receiving solenoid. 
 
     
     
       8. The wireless power receiving device of  claim 1 , wherein the wireless power receiving device comprises a wristwatch. 
     
     
       9. A wireless power receiving device having opposing first and second faces, wherein the wireless power receiving device is configured to receive wireless power signals from a wireless power transmitting device, the wireless power receiving device comprising:
 a housing having a housing wall at the first face; 
 a display mounted to the housing at the second face; and 
 a power receiving solenoid that extends at least partially along the housing wall, that has a solenoid core, and that is configured to receive the wireless power signals from the wireless power transmitting device, wherein the solenoid core comprises a first portion, a second portion extending parallel to the first portion, and a third portion extending from an end of the first portion to an end of the second portion, wherein the power receiving solenoid comprises windings of wire wrapped around at least some of the solenoid core and wherein at least some of the solenoid core is free from windings of wire, wherein the first and second portions of the solenoid core each have an elongated strip shape and the third portion of the solenoid core has a curved shape. 
 
     
     
       10. The wireless power receiving device of  claim 9  wherein the windings of wire are wrapped around at least some of the third portion of the solenoid core. 
     
     
       11. The wireless power receiving device of  claim 10  wherein the third portion of the solenoid core is curved. 
     
     
       12. The wireless power receiving device of  claim 9  wherein the wireless power receiving device comprises a wristwatch. 
     
     
       13. A wristwatch having opposing first and second faces, wherein the wristwatch is configured to receive wireless power signals from a wireless power transmitting device, the wristwatch comprising:
 a housing having a housing wall at the first face; 
 a display mounted in the housing at the second face; and 
 a power receiving solenoid that has a solenoid core and that is configured to receive the wireless power signals from the wireless power transmitting device, wherein the solenoid core has a first strip portion extending along a first longitudinal axis, a second strip portion extending along a second longitudinal axis parallel to the first longitudinal axis, and a curved portion that extends from the first strip portion to the second strip portion, the power receiving solenoid further comprising windings of wire that overlap the curved portion of the solenoid core. 
 
     
     
       14. The wristwatch of  claim 13 , wherein the windings of wire overlap the first strip portion of the solenoid core. 
     
     
       15. The wristwatch of  claim 14 , wherein the windings of wire overlap the second strip portion of the solenoid core. 
     
     
       16. The wristwatch of  claim 15 , further comprising:
 a battery; and 
 wireless power receiving circuitry coupled to the windings of wire and configured to charge the battery using the wireless power signals received by the power receiving solenoid.

Description:
This application is a continuation of U.S. patent application Ser. No. 16/872,243, filed May 11, 2020, which is a continuation of U.S. patent application Ser. No. 15/491,893, filed Apr. 19, 2017, which claims the benefit of provisional patent application No. 62/415,348, filed Oct. 31, 2016, each of which are hereby incorporated by reference herein in their entireties. 
    
    
     FIELD 
     This relates generally to wireless systems, and, more particularly, to systems in which devices are wirelessly charged. 
     BACKGROUND 
     In a wireless charging system, a wireless power transmitting device such as a device with a charging surface or magnetic charging cable may wirelessly transmit power to a portable electronic device. The portable electronic device may receive the wirelessly transmitted power and may use this power to charge an internal battery or to power the device. In some situations, it may be challenging to achieve desired levels of charging efficiency due to the way in which the portable electronic device and wireless power transmitting device are oriented with respect to each other and the configurations used for the wireless charging components in these devices. 
     SUMMARY 
     A wireless power transmitting device such as a device with a wireless charging surface or a device with a cradle or other support structure can transmit power wirelessly to a wireless power receiving device. The wireless power receiving device may have a housing such as a metal housing. A display may be mounted in the metal housing on a front face of the device. A rear housing wall on a rear face of the device may be provided with a wireless power receiving solenoid. 
     The wireless power receiving solenoid may have a core formed from a magnetic material such as a ferrite strip that is wrapped with a wire. The wire may be formed from a solid metal wire with a dielectric coating, a solid metal wire with a magnetic coating layer, a metal wire having a rectangular cross-sectional shape, or a wire formed form intertwined metal filaments. 
     The solenoid may have a linear strip shape that extends along a longitudinal axis. The wireless power receiving device may have a strap coupled to sidewalls of the metal housing. The longitudinal axis may extend in a direction that is perpendicular to the strap and parallel to the sidewalls to which the strap is coupled. 
     The wireless power receiving solenoid may have opposing first and second ends. In some arrangements, the wireless power transmitting device may have a wireless power transmitting solenoid with opposing first and second ends that are configured to transmit wireless power signals respectively to the first and second ends of the wireless power receiving solenoid when the wireless power receiving solenoid has been received within a cradle. The wireless power receiving device may also use the wireless power receiving solenoid to receive power from a wireless charging mat or other wireless power transmitting device that emits wireless power signals from a wireless charging surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram of an illustrative wireless charging system in accordance with some embodiments. 
         FIG.  2    is a top view of an illustrative wireless charging system having a wireless power transmitting device that forms a wireless charging surface in accordance with an embodiment. 
         FIG.  3    is a diagram of an illustrative array of wireless power transmitting coils for a wireless charging surface in accordance with an embodiment. 
         FIG.  4    is a perspective view of an illustrative portable electronic device such as a wristwatch that may be wirelessly charged in accordance with an embodiment. 
         FIG.  5    is a perspective view of an illustrative wireless power receiving solenoid that may be used in a wireless power receiving device in accordance with an embodiment. 
         FIGS.  6 ,  7 , and  8    are cross-sectional side views of illustrative conductive strands of material that may be used in forming wireless power transmitting and wireless power receiving solenoids in accordance with an embodiment. 
         FIG.  9    is a cross-sectional side view of an illustrative wireless power receiving device resting horizontally on a wireless charging surface of an illustrative wireless power transmitting device with an array of wireless power transmitting coils in accordance with an embodiment. 
         FIG.  10    is a cross-sectional side view of an illustrative wireless power receiving device resting vertically on a wireless charging surface of the illustrative wireless power transmitting device of  FIG.  9    in accordance with an embodiment. 
         FIG.  11    is a perspective view of an illustrative wireless power receiving device receiving wireless power signals from a wireless power transmitting device having an array of coils in accordance with an embodiment. 
         FIG.  12    is a cross-sectional side view of an illustrative linear wireless power receiving solenoid having first and second ends that are receiving wireless power signals from respective first and second ends of an illustrative C-shaped wireless power transmitting solenoid in accordance with an embodiment. 
         FIG.  13    is a cross-sectional side view of an illustrative linear wireless power receiving solenoid and an illustrative linear wireless power transmitting solenoid located so that first and second ends of the wireless power receiving solenoids are adjacent to respective first and second ends of the wireless power transmitting solenoid in accordance with an embodiment. 
         FIG.  14    is a cross-sectional side view of an illustrative system with a linear wireless power receiving solenoid and a U-shaped power transmitting solenoid in accordance with an embodiment. 
         FIGS.  15 ,  16 , and  17    are cross-sectional side views of an illustrative power receiving device having solenoids mounted respectively in positions that are proud of a rear housing surface, flush with a rear housing surface, and recessed with respect to at least some portions of a rear housing surface in accordance with an embodiment. 
         FIG.  18    is a perspective view of an illustrative cradle for a wireless power transmitting device with a wireless power transmitting solenoid in accordance with an embodiment. 
         FIG.  19    is a perspective view of the illustrative cradle of  FIG.  18    being mated with a wireless power receiving solenoid on a watch housing in accordance with an embodiment. 
         FIGS.  20  and  21    are perspective views of illustrative wireless power transmitting devices being coupled to a wireless power receiving solenoid on a watch in accordance with an embodiment. 
         FIG.  22    is a rear perspective view of an illustrative watch housing having rear housing wall recesses adjacent to opposing ends of an elongated strip-shaped (linear) wireless power receiving solenoid on the rear face of the watch housing to enhance wireless power transfer performance in accordance with an embodiment. 
         FIGS.  23 - 32    are rear views of illustrative watches with wireless charging solenoids in illustrative configurations in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     A wireless power system may have a wireless power transmitting device such as a wireless charging mat, wireless charging puck, wireless charging stand, wireless charging table, or other wireless power transmitting equipment. The wireless power transmitting device may have one or more coils that are used in transmitting wireless power to a wireless power receiving device. In some configurations, the coils may be implemented using elongated solenoids. A wireless power transmitting solenoid may be used, for example, in wireless power transmitting equipment with a magnetic charging cable, stand, or other equipment that contains a support structure such as a cradle. In other configurations, arrays of planar coils may be used in forming a wireless charging surface for a wireless power transmitting device. The wireless power receiving device may be a cellular telephone, watch, media player, tablet computer, earbuds, remote control, laptop computer, or other portable electronic device. The wireless power receiving device may have a wireless power receiving solenoid that receives wireless power signals transmitted by the wireless power transmitting device. 
     During operation, the wireless power transmitting device may supply alternating-current signals to one or more wireless power transmitting coils. This causes the coils to transmit alternating-current electromagnetic signals (sometimes referred to as wireless power signals) to the wireless power receiving device. The wireless power receiving device may have one or more coils such as an elongated wireless power receiving solenoid for receiving the transmitted wireless power signals. 
     With one illustrative configuration, the wireless power receiving device may have an elongated coil with wire wrapped around a magnetic core that forms a solenoid. Configurations in which the wireless power transmitting device has a wireless charging surface with an array of coils or a cradle or other structure with a wireless power transmitting solenoid that supplies wireless power to a wireless power receiving solenoid in a wireless power receiving device such as a watch may sometimes be described herein as an example. This is, however, merely illustrative. Any suitable configuration may be used for the wireless power transmitting device and any suitable configuration for the wireless power receiving device may be used, if desired. 
     An illustrative wireless power system (wireless charging system) is shown in  FIG.  1   . As shown in  FIG.  1   , wireless power system  8  may include a wireless power transmitting device such as wireless power transmitting device  12  and may include one or more wireless power receiving devices  10 . 
     Power transmitting device  12  may be a stand-alone power adapter or equipment that is coupled to power adapter circuitry using a cable. Device  12  may be a wireless charging mat with an array of coils mounted under a planar dielectric layer that serves as a wireless charging surface, a device with a charging cable (e.g., a magnetic charging cable having a puck with a wireless power transmitting coil and magnets for coupling the puck to a wireless power receiving device), a stand (e.g., a dock), a table with an array of coils, or other device that includes power adapter circuitry, may include a wireless charging cradle or other wireless power transfer component that is coupled to a power adapter or other equipment by a cable, may be a portable device, may be equipment that has been incorporated into furniture, a vehicle, or other system, or may be other wireless power transfer equipment. Illustrative configurations in which wireless power transmitting device  12  is a wireless charging device with a wireless charging surface or a wireless charging cradle of the type that may be incorporated into a puck on a cable or a cradle in a dock or other stand may sometimes be described herein as examples. 
     Each power receiving device  10  in system  8  may be a portable electronic device such as a wristwatch, a cellular telephone, a laptop computer, a tablet computer, or other electronic equipment. Power transmitting device  12  may be coupled to a source of alternating current voltage such as alternating current power source  50  (e.g., a wall outlet that supplies line power or other source of mains electricity), may have a battery such as battery  38  for supplying power, and/or may have another source of power. Power transmitting device  12  may have a power converter such as AC-DC power converter  40  for converting power from a mains power source or other power source into DC power that is used to power control circuitry  42  and other circuitry in device  12 . 
     During operation, a controller in control circuitry  42  may use wireless power transmitting circuitry  34  and one or more coil(s)  36  coupled to circuitry  34  to transmit alternating current electromagnetic signals  48  to device  10  and thereby convey wireless power to power receiving circuitry  46  of device  10 . Power transmitting circuitry  34  may have switching circuitry (e.g., transistors) that are turned on and off based on control signals provided by control circuitry  42  to create AC current signals through coil(s)  36 . As the AC currents pass through coil(s)  36 , alternating-current electromagnetic fields (wireless power signals  48 ) are produced that are received by corresponding coil(s)  14  coupled to wireless power receiving circuitry  46  in receiving device  10 . When the alternating-current electromagnetic fields are received by coil  14 , corresponding alternating-current currents and voltages are induced in coil  14 . Rectifier circuitry in circuitry  46  may convert received AC signals (received alternating-current currents and voltages associated with wireless power signals) from coil(s)  14  into DC voltage signals for powering device  10 . The DC voltages may be used in powering components in device  10  such as display  52 , touch sensor components and other sensors  54  (e.g., accelerometers, force sensors, temperature sensors, light sensors, pressure sensors, gas sensors, moisture sensors, magnetic sensors, etc.), wireless communications circuits  56  for communicating wirelessly with control circuitry  42  of transmitter  12  and/or other equipment, audio components, and other components (e.g., input-output devices  22  and/or control circuitry  20 ) and may be used in charging an internal battery in device  10  such as battery  18 . 
     Devices  12  and  10  may include control circuitry  42  and  20 . Control circuitry  42  and  20  may include storage and may include processing circuitry such as microprocessors, power management units, baseband processors, digital signal processors, microcontrollers, and/or application-specific integrated circuits with processing circuits. Control circuitry  42  and  20  may be configured to execute instructions for implementing desired control and communications features in system  8 . For example, control circuitry  42  and/or  20  may be used in determining power transmission levels, processing sensor data, processing user input, processing other information such as information on wireless coupling efficiency from transmitting circuitry  34 , processing information from receiving circuitry  46 , using information from circuitry  34  and/or  46  to determine when to start and stop wireless charging operations, adjusting charging parameters such as charging frequencies, coil assignments in a multi-coil array, and wireless power transmission levels, and performing other control functions. Control circuitry  42  and/or  20  may be configured to perform these operations using hardware (e.g., dedicated hardware or circuitry) and/or software (e.g., code that runs on the hardware of system  8 ). Software code for performing these operations may be stored on non-transitory computer readable storage media (e.g., tangible computer readable storage media). The software code may sometimes be referred to as software, data, program instructions, instructions, or code. The non-transitory computer readable storage media may include non-volatile memory such as non-volatile random-access memory (NVRAM), one or more hard drives (e.g., magnetic drives or solid state drives), one or more removable flash drives or other removable media, other computer readable media, or combinations of these computer readable media. Software stored on the non-transitory computer readable storage media may be executed on the processing circuitry of control circuitry  42  and/or  20 . The processing circuitry may include application-specific integrated circuits with processing circuitry, one or more microprocessors, or other processing circuitry. 
     Device  12  and/or device  10  may communicate wirelessly using in-band or out-of-band communications. Devices  10  and  12  may, for example, have wireless transceiver circuitry in control circuitry  42  and  20  (and/or wireless communications circuitry such as circuitry  56  of  FIG.  1   ) that allows wireless transmission of signals between devices  10  and  12  (e.g., using antennas, using coils  36  and  14 , etc.). 
     With one illustrative configuration, wireless transmitting device  12  is a wireless charging mat or other wireless power transmitting equipment that has an array of coils that supply wireless power over a wireless charging surface. This type of arrangement is shown in  FIG.  2   . As shown in  FIG.  2   , wireless power receiving device  10  may be located over one or more of coils  36  during charging. Coils  36  may be arranged across a charging surface with any suitable tiling pattern (rectangular, hexagonal, etc.). As an example, a coil array may have rows and columns of coils  36  each of which is placed in a non-overlapping rectangular tile location, a coil array may have rectangularly tiled rows and columns of coils  36  in two or more staggered arrays, may have coils  36  in a hexagonally tiled array pattern such as a pattern in which each hexagonal tile includes a respective non-overlapping coil  36 , or may be arranged in a set of two or more or three or more overlapping hexagonally tiled sets of coils. An illustrative coil array configuration based on three staggered sets (arrays) of hexagonally tiled coils  36  is shown in  FIG.  3   . The illustrative coil array of  FIG.  3   , device  12  may be associated with a charging mat or other device with a charging surface and may have a first layer of hexagonally tiled coils  36 A, a second layer of hexagonally tiled coils  36 B, and a third layer of hexagonally tiled coils  36 C. During operation, control circuitry  42  of device  10  may direct circuitry  34  to route alternating current signals to a desired coil or coils in a desired one of these three overlapping and staggered layers to optimize overlap between the transmitting coil that is in use by device  12  and the receiving coil(s)  14  in device  10 . 
       FIG.  4    is a perspective view of power receiving device  10  in an illustrative configuration in which power receiving device  10  is a wristwatch device. In this example, device (watch)  10  has a strap such as strap  60  that is coupled to left and right sidewalls of watch housing  62 . Strap  60  may be coupled to housing  62  using a spring-loaded pin, using a clip, using screws or other fasteners, by routing portions of strap  60  through a slot or other opening in housing  62 , using adhesive, by forming strap and housing  62  as portions of a common structure, using other coupling techniques, or using a combination of these techniques. Strap  60  may have a clasp such as clasp  64  that allows strap  60  to be secured around a user&#39;s wrist. Elastic straps without clasps and straps with other fastening mechanisms may also be used, if desired. 
     Housing  62  may be formed from one or more materials such as metal (aluminum, stainless steel, gold, etc.), glass, carbon-fiber composites and other fiber-composite materials, polymer (plastic), ceramic, other materials, and/or combinations of these material. Housing  62  may have a square outline or other rectangular outline (footprint when viewed from above) or may have a circular outline, oval outline, etc. Display  66  may be mounted on a front face of housing  62  and buttons (e.g., a watch crown, etc.) such as button  68  may be mounted on sidewalls or other portions of housing  62 . An opposing rear face of housing  62  may be formed from a metal rear housing wall structure or other suitable housing wall structure and may be provided with windows to accommodate light emission and/or light detection and/or may be provided with a solenoid (coil)  14  to receive wireless power from device  12 . 
     A solenoid on the rear face of housing  62  of device  10  may have a linear configuration of the type shown by illustrative solenoid  14  of  FIG.  5   . Solenoid  14  of  FIG.  5    has an elongated linear core such as strip-shaped solenoid core  14 C wrapped with multiple turns of wire  14 W. Core  14 C may be formed from a magnetic material having a relatively high relative permeability. For example, in configurations in which wireless power transmitting circuitry  34  and wireless power receiving circuitry  46  operate at alternating current frequencies of about 300-400 kHz, the relative permeability of core  14 C may be 1000-5000 at 300-400 kHz, at least 1000 at 300-400 kHz, 2000-6000 at 300-400 kHz, or less than 6000 at 300-400 kHz. If desired, the relative permeability of core  14 C may be lower or higher. As an example, if circuitry  34  and  46  is configured to operate at a higher frequency (e.g., 6 MHz), the relative permeability of core  14 C may be 100 at 6 MHz. Core  14 C may be formed from a ferrite (e.g., a magnesium zinc ferrite) or other suitable magnetic material. Core  14 C may be elongated along longitudinal axis  70 . Length L of solenoid  14  may be 2.4 cm, 1-10 cm, 1-5 cm, 2-5 cm, 1-3 cm, more than 0.5 cm, less than 4 cm, or other suitable length. Width W of core  14 C may be 0.6 cm, 0.3 to 1.2 cm, 0.3 to 1 cm, 0.2 to 1.5 cm, at least 0.2 cm, at least 0.3 cm, less than 1.2 cm, less than 2 cm, less than 4 cm, or other suitable width. Thickness T of core  14 C may be 1 mm, 0.5 to 2 mm, less than 3 mm, less than 5 mm, more than 0.2 mm, more than 1 mm, 0.1 cm, 0.05-0.2 cm, at least 0.05, less than 0.4 cm, or other suitable thickness. Solenoid  14  may be an elongated linear (strip-shaped) solenoid and core  14 C may extend along a longitudinal axis. Thickness T may extend outwardly from the rear housing wall of housing  62 . Width W may run parallel to the surface of the rear housing wall of housing  62 . With one illustrative configuration, width W is at least 4 times more than thickness T and length L is at least 4 times width W. Other configurations may be used for solenoid  14 , if desired. The longitudinal axis of solenoid  14  may extend parallel to the opposing left and right sidewalls of housing  62  to which strap  60  is coupled. 
     Wire  14 W may be formed from solid copper wire or other suitable conductive strands of material. There may be 2-100, more than 10, more than 40, more than 120, less than 300, less than 150, less than 75, or other suitable number of turns of wire  14 W wrapped around core  14 C (longitudinal axis  70 ). The diameter of wire  14 W may be 0.1 mm, 0.05-0.2 mm, more than 0.03 mm, more than 0.08 mm, less than 0.3 mm, less than 1 mm, or other suitable diameter. 
       FIG.  6    shows how wire  14 W may have solid cores such as core  14 W- 1  coated with one or more coating layers such as layer  14 W- 2 . In general, wire  14 W may have one or more, two or more, three or more, or four or more layers including core  14 W- 1  and these layers may be dielectrics and/or conductors. As one example, core  14 W- 1  may be copper and coating  14 W- 2  may be a magnetic material such as iron. As another example, core  14 W- 1  may be a metal such as copper and coating  14 W- 2  may be a polymer coating or other dielectric coating. Configurations in which the sides of strand  14 W are flat to help allow for a high density of turns around core  14 W (see, e.g., strand  14 W of  FIG.  7   , which has a rectangular cross-sectional shape) and in which multiple smaller strands  14 W′ are intertwined to form strand  14 W (as shown in  FIG.  8   ) may also be used. 
     In some situations, a user may place housing  62  on a charging surface so that the front or rear face of housing  62  lies flat on the charging surface. As shown in  FIG.  9   , for example, housing  62  may be placed so that the front and rear faces of housing  62  each lie in a plane parallel to the charging surface of device  12  (parallel to the X-Y plane). In this configuration, magnetic field B from coil(s)  36  may pass laterally (horizontally in the configuration of  FIG.  9   ) through solenoid  14 . 
     In some scenarios, a user may place housing  62  on its side on a wireless charging surface, as shown in  FIG.  10   . For example, when a user removes a watch, the user may place the watch on a charging surface so that the sidewalls of housing  62  that are most adjacent to wrist strap  60  (the vertically extending sidewalls of housing  62  in the example of  FIG.  10   ) are oriented parallel to surface normal n of the charging surface of wireless device  12  (along the vertical Z axis). Strap  60  may extend parallel to the charging surface and may be perpendicular to surface normal n. In some situations, for example, if band  60  is an elastomeric loop and has no clasps, it may be impossible for a user to place the rear face of housing  62  on the charging surface and the most likely orientation for device  10  may therefore be the orientation shown in  FIG.  10   . In this orientation in which device housing  62  is resting on a housing edge, magnetic field B from coil(s)  36  may pass vertically through solenoid  14  (along axis Z of  FIG.  10   ). 
     The use of a rear-mounted solenoid such as solenoid  14  in the examples of  FIGS.  9  and  10    allows device  10  to receive satisfactory wireless power in both horizontal (parallel) and vertical (perpendicular) orientations of solenoid  14  (longitudinal axis  70 ) relative to the coil array formed under the charging surface of device  12 . The coupling efficiency between devices  12  and  10  in the scenarios of  FIGS.  9  and  10    may be, for example, between 5% and 25%, above 4%, below 30%, or other suitable values. Coils  36  may have any suitable shape and size. For example, coils  36  may be hexagonally tiled coils in three staggered layers (as described in connection with  FIG.  3   ) and may have coil diameters of 1-10 cm, 2-5 cm, 2-4 cm, 2-3 cm, more than 0.5 cm, less than 15 cm, or other suitable coil diameter values. 
       FIG.  11    is a perspective view of device  10  in an illustrative configuration in which solenoid  14  is oriented perpendicular to the surface (X-Y plane) of device  12 . As shown in  FIG.  11   , solenoid  14  may have an elongated shape (e.g., an elongated strip shape) that extends across some or all of rear wall  62 R of housing  62 . Configurations in which solenoid  14  is mounted elsewhere in watch housing  62  may also be used. 
     It may be desirable to place solenoid  14  within a charging cradle in device  12  during charging. A cradle in device  12  may, for example, have a single wireless power transmitting coil such as illustrative C-shaped solenoid  36  of  FIG.  12   . As shown in  FIG.  12   , solenoid  36  may, in this illustrative configuration, have multiple turns of wire  36 W (e.g., wire such as wire  14 W of solenoid  14 ) wrapped around magnetic core  36 C (see, e.g., the materials and structures used in forming core  14 C of solenoid  14 ). This type of arrangement for wireless power transmitting solenoid  36  may be used in a wireless charging puck, in a stand, in a puck or other device that is tethered to the end of a cable, or other wireless power transmitting device  12 . As shown in  FIG.  12   , the C shape of core  36 C allows the ends of wireless power transmitting solenoid  36  (e.g., ends  72  of core  36 C) to be placed adjacent to ends  74  of core  14 C (e.g., the opposing ends of solenoid  14 ), thereby enhancing the efficiency with which magnetic field B from C-shaped solenoid  36  is coupled into solenoid  14 . 
     If desired, solenoid  36  may be formed from a linear solenoid core and solenoid  14  may be formed from a linear solenoid core, as shown in  FIG.  13   . In arrangements of this type in which solenoids  36  and  14  are elongated linear solenoids, the opposing ends of power transmitting solenoid  36  may be placed adjacent to corresponding ends of power receiving solenoid  14  to enhance power transfer efficiency. Solenoids  36  of  FIG.  13    may be mounted in a support structure such as a cradle in device  12 . Solenoid  14  of  FIG.  13    may be mounted on housing  62  at the rear face of device  10 . 
       FIG.  14    is a cross-sectional side view of system  8  in an illustrative configuration in which wireless power transmitting device  12  has a U-shaped wireless power transmitting solenoid  36 . Wireless power receiving solenoid  14  may be a linear solenoid that is received within a cavity formed between the opposing ends of U-shaped power transmitting solenoid  36 . As with the solenoid wireless power transmitting configurations of  FIGS.  12  and  13   , power may be transmitted wirelessly when solenoid  14  is receiving within a cradle recess or other support structure cavity so that the ends of the wireless power transmitting solenoid are adjacent to the corresponding ends of the wireless power receiving solenoid. Magnets  82  and  84  (and/or iron bars or other magnetic members) may be used to help temporarily hold device  10  against device  12  (e.g., while solenoid  14  is in the cradle formed from U-shaped solenoid  36  or a cradle with a wireless power transmitting solenoid of other suitable shapes). If desired, a shielding layer such as shielding layer  80  may be formed under solenoid  36 . Layer  80  may be, for example, a layer of copper or other metal. The solenoid-based coils  36  for device  12  that are shown in  FIGS.  12 ,  13 , and  14    may be incorporated into a cradle that receives solenoid  14  in a puck or other structure tethered to the end of a cable, into a cradle that receives solenoid  14  in a stand, or in other equipment configured to receive solenoid  14  on rear housing wall  62 R of housing  62 . 
     Solenoid  14  may be incorporated into device  10  in a position in which solenoid  14  is proud of the outermost surface of rear housing wall  62 R. For example, dielectric material  62 D (polymer, ceramic, glass, etc.) may be used to hold solenoid  14  in a position of the type shown in  FIG.  15    in which solenoid  14  is spaced apart from planar rear surface  62 R of housing  62  of device  10 .  FIG.  16    is a cross-sectional side view of device  10  in a configuration in which solenoid  14  has been mounted flush with the outer surface of housing  62 . As shown in  FIG.  16   , inner surface  14 ′ of solenoid  14 , which faces housing  62 , may be flush with the outwardly facing (external) surface  62 R of the planar rear housing wall of housing  62 . 
       FIG.  17    shows how a portion such as region  62 R′ of rear housing surface  62 R may be recessed below the rest of rear surface  62 R. Inner solenoid surface  14 ′ may be flush with recessed surface  62 R and may therefore cause inner surface  14 ′ to be recessed with respect to planar portions of some or all of rear surface  62 R. Recessing solenoid  14  as shown in  FIG.  17    may help enhance the aesthetics of device  10 . Recesses (e.g., notches) may be formed in housing  62  so that housing  62  does not hinder magnetic field coupling with solenoid  14 . If desired, solenoid  14  may be mounted on or adjacent to the interior surface of rear housing wall  62 R (e.g., when all of wall  62 R or a window in wall  62 R are formed from plastic, glass, sapphire or other crystalline materials, or other dielectric materials). As when mounted in configurations on the outer surface of wall  62 R, solenoid  14  may extend across the rear face of device  10  (e.g., solenoid  14  may be a strip-shaped solenoid that lies in a plane parallel to the exterior surface of rear housing wall  62 R). 
     As shown in  FIGS.  15 ,  16 , and  17   , dielectric  80  may cover some or all of solenoid  14  (e.g., dielectric material that forms a rear housing wall and/or a filler or coating such as a layer of plastic, glass, ceramic, etc. may that cover solenoid  14 .) to provide environmental sealing and to enhance the appearance of device  10 . Dielectric  80 , which may be considered to form a portion of housing  62 , may be configured to allow solenoid  14  to be received within a charging cradle having a solenoid of the type shown in  FIG.  12 ,  13   , or  14 , or other suitable wireless power transmitting solenoid  36 . 
     As shown in  FIG.  18   , solenoid  36  may be mounted in cradle  90  in device  12 . Cradle  90  may have support structure  92  such as a copper cradle structure, other metal cradle structures, or other support structures. Solenoid  36  may be a linear solenoid, a U-shaped solenoid, a C-shaped solenoid, or may have other suitable solenoid configurations. Support structure  92  may form part of a puck, stand, charging mat, or other wireless power transmitting device  12 . In the example of  FIG.  18   , solenoid  36  has been configured so that solenoid end portions  36 E lie on opposing ends of cavity (recess)  94  (e.g., solenoid  36  of  FIG.  18    has a U-shape or a C-shape). Cavity  94  has been configured to receive solenoid  14  of device  10 , as shown by in the perspective view of device  10  and cradle  90  of  FIG.  19   . 
     If desired, a shield layer may be formed in device  12 . As shown in  FIGS.  20  and  21   , for example, solenoid  36  may have opposing ends  36 E that are configured to mate with corresponding ends of solenoid  14 . When mounted in device  12  ( FIG.  21   ), shield layer  96  may lie under solenoid  36 . Shield layer  96  may be formed from a copper plate or a layer of other shielding material (e.g., other metals, etc.). The presence of a metal shield under solenoid  36  (e.g., under a cradle or other structure supporting solenoid  36 , etc.) may help improve coupling between solenoids  14  and  36  and may help improve power transfer efficiency. 
       FIG.  22    shows how recessed portions  62 R′ may be formed in rear housing wall  62 R (e.g., in planar portions of wall  62 R that cover some or all of the rear face of device  10 ). Recesses in housing  62  such as recessed portions  62 R′ in rear housing wall  62 R may be formed adjacent to the opposing ends  14 E of elongated solenoid  14 . This enhances the ability of magnetic fields to couple into ends  14 E and thereby enhances coupling and charging (power transfer) efficiency. 
     Additional illustrative configurations for solenoid  14  are shown in  FIGS.  23 ,  24 ,  25 ,  26 ,  27 ,  28 ,  29 , and  30   . In these illustrative configurations, first and second sets of turns of wire  14 W are formed on first and second respective portions of core  14 C. This creates first and second solenoid portions for solenoid  14 , which can be operated together (e.g., in series) or independently (e.g., by switching a solenoid portion having a higher coupling efficiency into use while switching a solenoid portion with lower coupling efficiency out of use, etc.). Solenoid  24  may curved along at least part of its length while being strip-shaped (length at least 5-20 times thickness, width at least 3-10 times width, etc.) while extending across the rear face of device  10  parallel to the surface of rear wall of housing  62 . Core  14 C may be curved along its length while remaining in a plane parallel to the plane of the rear face of device  10  and may, if desired, have both straight and curved segments. Solenoid  14  may extend across the rear face of device  10  on the inside or outside of rear housing wall  62 R and may, if desired, be flush with surface  62 R, proud of surface  62 R, or on a recessed portion of surface  62 R. The portion of core  14 C that is wrapped with windings  14 W may be straight or may, as shown in  FIG.  30   , by curved. If desired, cores  14 C may reside primarily or exclusively within wire  14 W (see, e.g., the arrangements of  FIGS.  31  and  32   ). In this type of configuration, cores  14 C may reside within wires  14 W without protruding from within wires  14 W or may protrude slightly from within wires  14 W. The solenoids formed using this type of core and winding arrangement may, if desired, be straight and may be oriented vertically or horizontally (e.g., parallel to strap  60  of  FIG.  4    or orthogonal to strap  60 ). Other configurations may be used for solenoid  14  if desired. The arrangements of  FIGS.  23 ,  24 ,  25 ,  26 ,  27 ,  28 , and  29    are illustrative. 
     The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20211209
Publication Date: 20230321
Grant Date: 20230321
Priority Date: 20161031
Inventors: PINCIUC, Christopher M.
MOUSSAOUI, ZAKI
Assignee: APPLE INC
CPC Classifications: [{"code": "H01F27/25", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F7/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/0042", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01F27/2823", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F38/14", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J50/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/90", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "A44C5/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/0044", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F38/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/24", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F38/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/24", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/0044", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/0042", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F38/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01F27/2823", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/90", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/16", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 60190634