PATENT DOCUMENT

Publication Number: US-12081035-B2
Application Number: US-202117472497-A
Country: US
Kind Code: B2

Title: Docking stations with hinged charging puck

Abstract:
Charging devices that can securely hold an electronic device in a useful position, fold into a compact shape, and provide power to the electronic device. One example can provide a wireless charger that can include a wireless charging assembly, a base, and a hinge connecting the wireless charging assembly to the base. When opened, the wireless charging assembly can be positioned upright relative to the base such that an electronic device being charged by the wireless charging assembly can be maintained in an upright position for easy viewing. The wireless charging assembly can be rotated, folded, or otherwise closed into a cavity or passage in the base, which can provide for easy transport. The hinge can be configured to readily open for use, while providing increased friction to resist closing. This increased friction can help the charger to securely hold the electronic device in place while charging.

Claims:
What is claimed is: 
     
       1. A wireless charger for an electronic device, the wireless charger comprising:
 a base having a passage, the passage defined by an inner sidewall extending from a top surface of the base to a bottom surface of the base; 
 a wireless charging assembly comprising:
 a housing including an enclosure covered by a cap, the cap forming a charging surface; and 
 a magnet array in the housing; 
 
 a hinge comprising:
 a stem having a sleeve having an opening at a first end, the stem further comprising a joining portion having a first end attached to the sleeve and a second end attached to the wireless charging assembly; 
 a first support block attached to the base and having a slot; 
 a first shaft having a first end inserted into the opening at the first end of the sleeve and a second end supported by the first support block; and 
 a first clip having a loop portion around the first shaft and a tab attached to a first end of the loop portion, the tab in the slot in the first support block. 
 
 
     
     
       2. The wireless charger of  claim 1  wherein the opening at the first end of the sleeve is cylindrical, the first shaft is cylindrical, and the sleeve further comprises a cylindrical opening at a second end, wherein the hinge further comprises:
 a second support block attached to the base and having a slot; 
 a second cylindrical shaft having a first end inserted into the opening at the second end of the sleeve and a second end supported by the second support block; and 
 a second clip having a loop portion around the second cylindrical shaft and a tab attached to a first end of the loop portion, the tab in the slot in the second support block. 
 
     
     
       3. The wireless charger of  claim 2  wherein the wireless charging assembly is movable between down position in which the wireless charging assembly is disposed within the passage and an up position in which the wireless charging assembly extends outside the base. 
     
     
       4. The wireless charger of  claim 3  wherein as the wireless charging assembly moves from the down position to the up position, the loop portion of the first clip loosens around the first shaft and as the wireless charging assembly moves from the up position to the down position, the loop portion of the first clip tightens around the first shaft. 
     
     
       5. The wireless charger of  claim 4  wherein the magnet array is movable within the wireless charging assembly to increase a magnetic attraction to a corresponding magnet array in the electronic device. 
     
     
       6. The wireless charger of  claim 5  wherein the cap for the housing for the wireless charging assembly comprises a silicone layer over a polycarbonate layer. 
     
     
       7. The wireless charger of  claim 6  wherein the enclosure for the wireless charging assembly comprises stainless steel. 
     
     
       8. The wireless charger of  claim 6  wherein the enclosure for the wireless charging assembly comprises aluminum. 
     
     
       9. The wireless charger of  claim 4  wherein the wireless charging assembly further comprises a first closure magnet and the base further comprises a second closure magnet, wherein when the wireless charging assembly is in the down position, the first closure magnet and the second closure magnet position the wireless charging assembly in the passage in the base. 
     
     
       10. The wireless charger of  claim 4  wherein the wireless charging assembly further comprises a first closure magnet and the base further comprises a step, the step housing a second closure magnet, wherein when the wireless charging assembly is in the down position, the wireless charging assembly rests on the step, and the first closure magnet and the second closure magnet position the wireless charging assembly in the passage in the base. 
     
     
       11. The wireless charger of  claim 4  wherein the wireless charging assembly further comprises a charging coil, the wireless charger further comprising:
 a wire to provide power to the charging coil, wherein the wire is routed through the sleeve and a slot in the stem of the hinge, wherein the hinge further comprises a cap over the slot in the stem of the hinge. 
 
     
     
       12. A wireless charger for an electronic device, the wireless charger comprising:
 a base having a passage, the passage defined by an inner sidewall extending from a top surface of the base to a bottom surface of the base; 
 a wireless charging assembly comprising:
 a housing including an enclosure covered by a cap, the cap forming a charging surface; and 
 a magnet array in the housing; 
 
 a hinge comprising:
 a stem having a sleeve having an opening at a first end, the stem further comprising a joining portion having a first end attached to the sleeve and a second end attached to the wireless charging assembly; 
 a first support block having a top surface attached to the base; 
 a first shaft having a first end inserted into the opening at the first end of the sleeve and a second end supported by the first support block; and 
 a first wrapped spring having a first end attached to a bottom surface of the first support block, the first wrapped spring wrapped around the first shaft. 
 
 
     
     
       13. The wireless charger of  claim 12  wherein the opening at the first end of the sleeve is cylindrical, the first shaft is cylindrical, and the sleeve further comprises a cylindrical opening at a second end, wherein the hinge further comprises:
 a second support block having a top surface attached to the base; 
 a second cylindrical shaft having a first end inserted into the opening at the second end of the sleeve and a second end supported by the second support block; and 
 a second wrapped spring having a first end attached to a bottom surface of the second support block, the second wrapped spring wrapped around the second cylindrical shaft. 
 
     
     
       14. The wireless charger of  claim 13  wherein the first wrapped spring includes a tapered portion wherein the first wrapped spring narrows towards a second end. 
     
     
       15. The wireless charger of  claim 14  wherein the wireless charging assembly is movable between down position in which the wireless charging assembly is disposed within the passage and an up position in which the wireless charging assembly extends outside the base. 
     
     
       16. The wireless charger of  claim 15  wherein as the wireless charging assembly moves from the down position to the up position, the first wrapped spring loosens around the first shaft and as the wireless charging assembly moves from the up position to the down position, the first wrapped spring tightens around the first shaft. 
     
     
       17. The wireless charger of  claim 15  wherein the magnet array is movable within the wireless charging assembly to increase a magnetic attraction to a corresponding magnet array in the electronic device. 
     
     
       18. The wireless charger of  claim 12  wherein the wireless charging assembly further comprises a charging coil, the wireless charger further comprising:
 a wire to provide power to the charging coil, wherein the wire is routed through the sleeve and a slot in the stem of the hinge, wherein the hinge further comprises a cap over the slot in the stem of the hinge. 
 
     
     
       19. A wireless charger for an electronic device, the wireless charger comprising:
 a base having a passage, the passage defined by an inner sidewall extending from a top surface of the base to a bottom surface of the base; 
 a wireless charging assembly comprising: 
 a housing including an enclosure covered by a cap, the cap forming a charging surface; and 
 a magnet array in the housing; 
 a hinge comprising:
 a stem having a sleeve having an opening at a first end, the stem further comprising a joining portion having a first end attached to the sleeve and a second end attached to the wireless charging assembly; 
 a first support block attached to the base and having a slot; 
 a first shaft having a first end inserted into the opening at the first end of the sleeve and a second end supported by the first support block, the first shaft including a plurality of lengthwise slots; and 
 a first plurality of bearings, each located in one of the slots in the first shaft, wherein each bearing in the first plurality of bearings is biased. 
 
 
     
     
       20. The wireless charger of  claim 19  wherein the opening at the first end of the sleeve is cylindrical, the first shaft is cylindrical, and the wireless charging assembly further comprises a charging coil, the wireless charger further comprising:
 a wire to provide power to the charging coil, wherein the wire is routed through the sleeve and a slot in the stem of the hinge, wherein the hinge further comprises a cover over the slot in the stem of the hinge.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     The present application claims the benefit of and priority to U.S. Provisional Application No. 63/082,183, filed Sep. 23, 2020, which is incorporated by reference. 
    
    
     BACKGROUND 
     Electronic devices have become ubiquitous over the past several years. We take them wherever we go. An electronic device can be integral to some of our actives, such as checking email, watching a video, or catching up on news. An electronic device can also be a supplement to some of our activities, such as when providing email updates or acting as a meeting reminder. 
     These electronic devices need to be charged periodically. Every so often, a cable needs to be inserted into the electronic device, or the electronic device needs to be put on a wireless charging pad or other surface, in order to charge a battery internal to or otherwise associated with the electronic device. 
     It can also be desirable to continue to use the electronic device while it is being charged. Accordingly, it can be desirable to provide chargers that can hold an electronic device in a useful position while the charger charges the battery of the electronic device. That is, it can be desirable that the charger hold the electronic device in an upright position such that a screen of the electronic device can be seen during charging. This can allow an electronic device to be used for watching videos, for viewing meeting reminders, and for other electronic device interactions during charging. 
     This charging can take place in various locations, for example, at work, in coffee shops, hotel rooms, and other locations. As a result, it can be desirable to bring these chargers along. To facilitate this, it can be desirable that the chargers fold up or otherwise close into a compact arrangement. 
     But electronic devices do have mass associated with them. It could be unfortunate if the weight of an electronic device caused a charger to inadvertently fold up or close while the electronic device was being charged. Accordingly, it can be desirable that a charger hold an electronic device securely in place while charging. 
     Thus, what is needed are charging devices that can securely hold an electronic device in a useful position, fold into a compact shape, and provide charging power to the electronic device. 
     SUMMARY 
     Accordingly, embodiments of the present invention can provide charging devices that can securely hold an electronic device in a useful position, fold into a compact shape, and provide charging power to the electronic device. 
     An illustrative embodiment of the present invention can provide a wireless charger for the wireless charging of an electronic device. The wireless charger can include a wireless charging assembly, a base, and a hinge connecting the wireless charging assembly to the base. The wireless charging assembly can wirelessly provide power to the electronic device. When the wireless charger is open, the wireless charging assembly can be positioned upright relative to the base such that an electronic device being charged by the wireless charging assembly can be maintained in an upright position for easy viewing. When the wireless charger is closed, the wireless charging assembly can be rotated, folded, or otherwise closed into a cavity or passage in the base. The resulting compact form factor can provide for easy transport. The hinge can be configured to allow the wireless charger to readily open for use, but can provide increased friction to resist closing. This increased friction can help the wireless charger to securely hold the electronic device in an upright position while charging. 
     These and other embodiments of the present invention can provide a wireless charger that includes a wireless charging assembly having a housing that includes a cap over an enclosure. The cap can include a high-friction or high-stiction surface that can increase a shear force needed to remove an electronic device from the charger. The cap can be at least partially adhesive to increase a normal force necessary to remove the electronic device from the charger. The cap can be formed of a rigid layer covered by a high-friction layer. For example, the cap can be formed of a polycarbonate layer covered by a softer, silicone layer. The cap can be formed using a double-shot molding process. The enclosure can be formed of aluminum, stainless steel, or other material. The enclosure can be formed by computer-numerically controlled (CNC) machining, metal-injection-molding, stamping, forging, by using a deep-draw process, or other technique. 
     The wireless charging assembly can include one or more magnets that can magnetically attract a corresponding one or more magnets in an electronic device in order to hold the electronic device in place in against the cap of the wireless charging assembly. The wireless charging assembly can include a magnet array that can magnetically attract a corresponding magnet array in an electronic device in order to hold the electronic device in place in against the cap of the wireless charging assembly. The magnet array can include a number of arcuate magnetic segments arranged in a circular, or partially circular configuration. The magnets can be fixed in position in the wireless charging assembly. This fixed position can be away from the cap in the enclosure to prevent accidental erasure of magnetic data, for example data on credit cards or transit passes. The magnetic field can be increased as the electronic device is or is about to be attached to the wireless charger. For example, an electro-magnet can be used to increase the magnetic field. Also or instead, the one or more magnets or magnet array can move towards the cap of the wireless charging assembly as the electronic device is or is about to be connected to the wireless charger. The use of an electro-magnet or moving one or more magnets or magnet array can improve the wireless charger&#39;s capacity to securely hold the electronic device in place during charging while limiting stray magnetic flux when an electronic device is not attached to the wireless charging assembly. 
     The wireless charging assembly can further include a coil and control electronics for charging a battery in or associated with an electronic device. The control electronics can receive power, for example from a connector on the wireless charger, via a tethered cable that terminates in the wireless charger, or from a battery or other power source in or associated with the wireless charger. The control electronics can use the received power to generate a current in the coil. The control electronics can modulate the current in the coil in the wireless charging assembly to generate a time-varying magnetic field. This time-varying magnetic field can induce a current in a corresponding coil in the electronic device. The current in the corresponding coil can be used to charge a battery in or associated with the electronic device. Similarly, data can be sent from the wireless charger to the electronic device. The control electronics can modulate the current in the coil in the wireless charging assembly to transmit data. This modulation can be in phase, frequency, amplitude, or other parameter or combination thereof. The resulting modulated flux can induce currents in a corresponding coil in the electronic device, which the electronic device can read as data. 
     Data can similarly be transmitted from the electronic device to the wireless charger. The coil in the wireless charging assembly can receive a time-varying magnetic field generated by the corresponding coil in the electronic device. This time-varying magnetic field can be a modulated magnetic field that can be used to convey data from the electronic device to the wireless charger. This modulation can be in phase, frequency, amplitude, or other parameter or combination thereof. 
     A ferrite shield can be included in the wireless charging assembly. The shield can be located behind and partially around the coil to direct the time-varying magnetic field and to improve coupling to the corresponding coil. Additional ferritic material (a ferrite filler) can be shaped around the control electronics to further direct the magnetic field and improve shielding. An e-shield can be placed over the coil, between the coil and the cap of the wireless charging assembly. The e-shield can be formed of a layer of copper or other conductive material to intercept electric fields between the coil in the wireless charging assembly and a corresponding coil in the electronic device. The e-shield can have a low magnetic permeability to pass magnetic fields between the coil and the corresponding coil. The e-shield can include breaks to prevent the formation of eddy currents. 
     The wireless charging assembly can further include identification components that an electronic device can use to determine that it is attached to a wireless charger. Once the wireless charger is identified, the electronic device can determine charging capabilities and other information about the wireless charger. The identification components can be near-field communication circuits or components, for example, a tag, a loop, and one or more capacitors. 
     These and other embodiments of the present invention can provide a wireless charger that includes a base to support a wireless charging assembly. The base can include a passage that the wireless charging assembly can fold up or close into. The base can be formed of aluminum, stainless steel, or other material. The base can be formed by CNC machining, metal-injection-molding, stamping, forging, by using a deep-draw process, or other technique. The base can rest on a foot that can be formed of plastic, silicone, or other non-marring material to protect desks and other surfaces on which the wireless charger can reside. 
     These and other embodiments of the present invention can provide a wireless charger that includes a hinge to attach a wireless charging assembly to the base. The hinge can include a stem having a sleeve. The sleeve can include a cylindrical opening at a first end and a cylindrical opening at a second end. The sleeve can further include one or more other openings for routing a wire internally from a connector, which can be located on the base, to the control electronics housed in the wireless charging assembly. The stem can further include a joining portion having a first end attached to the sleeve and a second end attached to the wireless charging assembly. The hinge can include a first support block attached to the base and having a slot and a second support block attached to the base and having a slot. A first cylindrical shaft can have a first end inserted into the opening at the first end of the sleeve. A second end of the first shaft can be supported by the first support block. A second cylindrical shaft can have a first end inserted into the opening at the second end of the sleeve. A second end of the second shaft can be supported by the second support block. The hinge can further include a first clip having a loop portion around the first shaft and a tab attached to a first end of the loop portion, where the tab is in the slot in the first support block, and a second clip having a loop portion around the second shaft and a tab attached to a first end of the loop portion, the tab in the slot in the second support block. 
     The hinge can allow the wireless charging assembly to be movable between down position in which the wireless charging assembly is disposed within the passage of the base and an up position in which the wireless charging assembly extends outside the base. As the wireless charging assembly moves from the down position to the up position, the loop portion of the first clip can loosen around the first shaft and the loop portion of the second clip can loosen around the second shaft. This can help the wireless charger to easily open for use. Conversely, as the wireless charging assembly moves from the up position to the down position, the loop portion of the first clip can tighten around the first shaft and the loop portion of the second clip can tighten around the second shaft. This can help the wireless charger to stay open and to more securely hold an electronic device in an upright position during charging. 
     These and other embodiments of the present invention can include other friction mechanisms in the hinge. For example, one or more wrapped springs can be used where a first end of a wrapped spring can attach to a support block while the remaining portion can be wrapped around a shaft. The wrapped springs can tighten around the shaft when the wireless charging assembly moves from the up position to the down position, thereby providing a resistance to the wireless charger closing and enabling the wireless charger to hold an electronic device in an upright position. The wrapped springs can loosen around the shaft when the wireless charging assembly moves from the down position to the up position, thereby allowing the wireless charger to readily open. 
     These and other embodiments of the present invention can include other friction mechanisms in the hinge. For example, a hinge can include a shaft including a plurality of lengthwise slots. A plurality of bearings can be positioned such that each bearing is located in one of the slots in the shaft. Each bearing can be biased, for example by a spring. As the shaft rotates in a first direction, the bearings can be pushed against their springs allowing the shaft to rotate. This can allow a wireless charger to easily open. As the shaft rotates in a second direction, the bearings can interfere with an inside surface of the sleeve of the stem, thereby increasing a resistance to rotation. This can provide resistance to the wireless charger closing and can enable the wireless charger to hold an electronic device in an upright position. 
     Portions of these hinges can be formed of aluminum, stainless steel, or other material. The hinges can be formed by CNC machining, metal-injection-molding, stamping, forging, by using a deep-draw process, or other technique. 
     These and other embodiments of the present invention can include features that can help to ensure that a wireless charger properly closes such that a top surface of a wireless charging assembly is properly aligned with a top surface of a base. In one example, a stop can be attached to a sleeve of a stem in a hinge. Specifically, the wireless charger can be properly closed. The stop can be soldered, or spot or laser-welded to the sleeve and against a surface of the base. In this way, as the wireless charger is closed, the stop can bottom out against the base ensuring that the wireless charger is properly closed. In these and other embodiments of the present invention, magnets, steps, and other features can be used to ensure that a wireless charger properly closes. 
     Various embodiments of the present invention can incorporate one or more of these and the other features described herein. A better understanding of the nature and advantages of the present invention can be gained by reference to the following detailed description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates a wireless charger according to an embodiment of the present invention; 
         FIG.  2    is an exploded view of the wireless charger of  FIG.  1   ; 
         FIG.  3    is an exploded view of a wireless charging assembly according to an embodiment of the present invention; 
         FIG.  4 A  and  FIG.  4 B  illustrate a hinge according to an embodiment the present invention; 
         FIG.  5    is an exploded diagram of a hinge according to an embodiment of the present invention; 
         FIG.  6    illustrates another hinge according to an embodiment of the present invention; 
         FIG.  7 A  and  FIG.  7 B  illustrate another hinge according to an embodiment of the present invention; 
         FIG.  8    illustrates a side view of a portion of a wireless charger according to an embodiment of the present invention; 
         FIG.  9    illustrates an underside view of a wireless charger according to an embodiment of the present invention; 
         FIG.  10    illustrates a side view of a portion of a wireless charger according to an embodiment of the present invention; 
         FIG.  11    illustrates an underside view of a wireless charger according to an embodiment of the present invention; 
         FIG.  12    illustrates a connector insert that can be inserted into a receptacle in a wireless charger according to an embodiment of the present invention; 
         FIG.  13    illustrates a hinge according to an embodiment of the present invention; 
         FIG.  14 A  and  FIG.  14 B  illustrate the movement of the hinge of  FIG.  13   ; 
         FIG.  15    illustrates a wireless charger according to an embodiment of the present invention; 
         FIG.  16    is an exploded view of the wireless charger of  FIG.  15   ; 
         FIG.  17    illustrates a hinge for use in the wireless charger of  FIG.  15   ; 
         FIG.  18 A  and  FIG.  18 B  illustrate another wireless charger according to an embodiment of the present invention; 
         FIG.  19 A  and  FIG.  19 B  illustrate another wireless charger according to an embodiment of the present invention; 
         FIG.  20    illustrates another wireless charger according to an embodiment of the present invention; 
         FIG.  21    is an exploded view of a wireless charger according to an embodiment of the present invention; 
         FIG.  22    illustrates a hinge for the wireless charger of  FIG.  21   ; 
         FIG.  23    illustrates a portion of the wireless charger of  FIG.  21   ; 
         FIG.  24    illustrates a wireless charger according to an embodiment of the present invention; 
         FIG.  25 A  and  FIG.  25 B  illustrates another wireless charger according to an embodiment of the present invention; 
         FIG.  26 A  and  FIG.  26 B  illustrate a telescoping mechanism according to an embodiment of the present invention; 
         FIG.  27 A  and  FIG.  27 B  illustrates another telescoping mechanism according to an embodiment of the present invention; 
         FIG.  28 A  and  FIG.  28 B  illustrate a wireless charger according to an embodiment of the present invention; 
         FIG.  29 A  and  FIG.  29 B  illustrate movements of portions of the wireless charger of  FIG.  28 A  and  FIG.  28 B ; 
         FIG.  30    is an exploded view of the wireless charger of  FIG.  28 A  and  FIG.  28 B ; 
         FIG.  31 A  and  FIG.  31 B  illustrate a wireless charger according to an embodiment of the present invention; 
         FIG.  32 A  and  FIG.  32 B  illustrate movements of portions of the wireless charger of  FIG.  31 A  and  FIG.  31 B ; 
         FIG.  33    is an exploded view of the wireless charger of  FIG.  31 A  and  FIG.  31 B ; 
         FIG.  34 A  and  FIG.  34 B  illustrate a wireless charger according to an embodiment of the present invention; 
         FIG.  35 A  and  FIG.  35 B  further illustrate the wireless charger of  FIG.  34 A ; 
         FIG.  36    shows a simplified representation of a wireless charging system incorporating a magnetic alignment system according to some embodiments; 
         FIG.  37 A  shows a perspective view of a magnetic alignment system according to some embodiments, and  FIG.  37 B  shows a cross-section through the magnetic alignment system of  FIG.  37 A ; 
         FIG.  38 A  shows a perspective view of a magnetic alignment system according to some embodiments, and  FIG.  38 B  shows a cross-section through the magnetic alignment system of  FIG.  38 A ; 
         FIG.  39    shows a simplified top-down view of a secondary alignment component according to some embodiments; 
         FIG.  40 A  shows a perspective view of a magnetic alignment system according to some embodiments, and  FIG.  40 B  shows an axial cross-section view through a portion of the system of  FIG.  40 A , while  FIGS.  40 C through  40 E  show examples of arcuate magnets with radial magnetic orientation according to some embodiments; 
         FIG.  41 A  and  FIG.  41 B  show graphs of force profiles for different magnetic alignment systems, according to some embodiments; 
         FIG.  42    shows a simplified top-down view of a secondary alignment component according to some embodiments; 
         FIG.  43 A  shows a perspective view of a magnetic alignment system according to some embodiments, and  FIGS.  43 B and  43 C  show axial cross-section views through different portions of the system of  FIG.  43 A ; 
         FIG.  44 A and  44 B  show simplified top-down views of secondary alignment components according to various embodiments; 
         FIG.  45    shows a simplified top-down view of a secondary alignment component according to some embodiments; 
         FIG.  46 A  through  FIG.  46 C  illustrate moving magnets according to an embodiment of the present invention; 
         FIGS.  47 A and  47 B  illustrate a moving magnetic structure according to an embodiment of the present invention; 
         FIGS.  48 A and  48 B  illustrate a moving magnetic structure according to an embodiment of the present invention; 
         FIGS.  49    through  FIG.  51    illustrate a moving magnetic structure according to an embodiment of the present invention; 
         FIG.  52    illustrates a normal force between a first magnet in a first electronic device and a second magnet in a second electronic device; 
         FIG.  53    illustrates a shear force between a first magnet in a first electronic device and a second magnet in a second electronic device; 
         FIG.  54    shows an exploded view of a wireless charger device incorporating an NFC tag circuit according to some embodiments; 
         FIG.  55    shows a partial cross-section view of a wireless charger device according to some embodiments; and 
         FIG.  56    shows a flow diagram of a process that can be implemented in a portable electronic device according to some embodiments. 
     
    
    
     DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
       FIG.  1    illustrates a wireless charger according to an embodiment of the present invention. Wireless charger  100  can include a wireless charging assembly  200 , base  300 , and hinge  400 . Wireless charging assembly  200  can include cap  210  and enclosure  220 . Base  300  can include a passage  320  defining interior sidewall  310 . Wireless charging assembly  200  can be attached to base  300  by hinge  400 . 
     Wireless charging assembly  200  can rotate relative to base  300  along hinge  400 . Wireless charging assembly  200  can be in an up position as shown, where wireless charging assembly  200  is positioned outside of base  300 . In this configuration, wireless charger  100  can be open. Wireless charging assembly  200  can move to a down or closed position, or wireless charging assembly  200  is positioned in passage  320  of base  300 . In this configuration, wireless charger  100  can be closed. 
     An electronic device (not shown) can securely be held by wireless charger  100  at cap  210 . Wireless charging assembly  200  can be tilted or repositioned relative to base  300  such that a screen (not shown) of the electronic device can be positioned at a proper angle for viewing. For example, wireless charging assembly  200  can be positioned 90 degrees relative to base  300 . Wireless charging assembly  200  can be positioned 80-90 degrees relative to base  300 . Wireless charging assembly  200  can be positioned 70-85 degrees relative to base  300 . Wireless charging assembly  200  can be positioned at another angle or through a range of angles relative to base  300 . 
       FIG.  2    is an exploded view of the wireless charger of  FIG.  1   . Wireless charger  100  can include wireless charging assembly  200 . Wireless charging assembly  200  can include cap  210  and enclosure  220 . Cap  210  can have a high friction or high stiction surface to increase a shear force needed to remove an electronic device (not shown) from the surface of cap  210 . The surface of cap  210  can be at least partially adhesive in order to increase a normal force needed to remove the electronic device from the surface of cap  210 . 
     Cap  210  can be formed of a rigid layer covered by a silicone layer. Cap  210  can be formed using a double-shot injection molding process, where a first shot molds a disk formed of polycarbonate or other material that is then covered with a second shot of silicone or other material. Enclosure  220  can be formed of aluminum, stainless steel, or other material. Enclosure  220  can be formed by metal injection molding, stamping, CNC machining, using a deep drawn process, forging, or other manufacturing technique. Similar portions of the other wireless chargers shown here or otherwise provided by embodiments of the present invention can be formed in a same or similar manner and they can be formed of a same or similar material or materials. 
     Base  300  can include passage  320  defining interior sidewall  310 . Base  300  can be positioned on foot  390 . Foot  390  can include a bottom layer  330  that can be made out of a non-scuff or non-marring material, such as silicone, to protect desktops and other surfaces on which wireless charger  100  can reside. Foot  390  can further have non-slip properties to keep wireless charger  100  from sliding during use. Foot  390  can include a second layer  340  formed of a more rigid material to secure bottom layer  330  to base  300 . Second layer  340  can include tabs  350  that can fit into slots (not shown) in a bottom side of base  300 . Tabs  352  on second layer  340  can support hinge  400 . 
     Base  300  and second layer  340  can be formed of aluminum, stainless steel, or other material. Base  300  and second layer  340  can be formed by CNC machining, metal-injection-molding, stamping, forging, by using a deep-draw process, or other technique. Second layer  340  can instead be formed of plastic, polycarbonate, or other material. Similar portions of the other wireless chargers shown here or otherwise provided by embodiments of the present invention can be formed in a same or similar manner and they can be formed of a same or similar material or materials. 
     Hinge  400  can include support blocks  410  and stem  420 . Stem  420  can terminate at first end  422 . First end  422  of stem  420  can be attached to wireless charging assembly  200 . Support blocks  410  can be attached using fasteners  412  to an underside of base  300 . Covers  402  can be used to protect hinge  400 . 
     Portions of hinge  400  and the other hinges shown herein or otherwise provided by embodiments of the present invention can be formed of aluminum, stainless steel, or other material. Hinge  400  and the other hinges can be formed by CNC machining, metal-injection-molding, stamping, forging, by using a deep-draw process, or other technique. Similar portions of the other wireless chargers shown here or otherwise provided by embodiments of the present invention can be formed in a same or similar manner and they can be formed of a same or similar material or materials. 
     Cable  600  can terminate in connector insert  610 , which can be inserted into connector receptacle  510  in base  300 . Connector receptacle  510  can be attached to wire  500 . Wire  500  can traverse base  300  and be attached to components in wireless charging assembly  200 . Examples of components that can be used in wireless charging assembly  200  are shown in the following figure. 
       FIG.  3    is an exploded view of a wireless charging assembly according to an embodiment of the present invention. Wireless charging assembly  200  can include cap  210  and enclosure  220 . In some circumstances it can be desirable for wireless charger  100  to simply hold an electronic device (not shown) securely in place. This can be true for example if a wired charging port on the electronic device is to be used in place of wireless charging by wireless charger  100 . Such a device, which can be referred to as a stand instead of or as well as a wireless charger, can include magnet array  260 . Magnet array  260  can include a number of arcuate magnets  261 , examples of which are shown beginning in  FIG.  36    below. Magnet array  260  can be supported by shield  262 . Shield  262  can act as a backplate to direct magnetic field lines of the arcuate magnets  261 . One or more shims  264  can be used to improve the alignment of the arcuate magnets  261  and magnet array  260 . 
     In other circumstances, it can be desirable for wireless charger  100  to provide charging for the electronic device while holding the electronic device in place. Accordingly, wireless charging assembly  200  can further include coil  230  and board  270 . Board  270  can include contacts  273 , which can connect to leads  232  on coil  230 . Coil  230  can be driven by currents generated by control circuitry  272  on board  270 . That is, control circuitry  272  can receive power and generate modulated currents in coil  230 . The modulated currents in coil  230  can create a magnetic field that can be directed by shield  240 . Shield  240  can improve coupling of the magnetic field to a corresponding coil (not shown) in the electronic device. The coupled magnetic field can be a time-varying magnetic field that can generate currents in the corresponding coil that can be used to charge a battery in or associated with the electronic device. 
     Control circuitry  272  can modulate currents provided to coil  230  in order to transmit data from wireless charger  100 . The modulation can be in phase, amplitude, frequency, or other parameter combination of parameters. The data can be generated by wireless charger  100  itself, or it can be dated received over cable  600  (shown in  FIG.  2   ) from an external device. Data can similarly be provided from the electronic device to wireless charger  100 . Control circuitry  272  can further include circuitry to read data coupled onto coil  230  by the electronic device. This received data can be used by wireless charger  100  itself, or the data can be provided to an external device over cable  600 . 
     In still other circumstances, it can be desirable for the electronic device to be able to determine that it is attached to wireless charger  100 . Accordingly, wireless charging assembly  200  can further include near-field circuitry (NFC) coil  250 . NFC coil  250  can include one or more components  252 , such as a radio-frequency (RF) tag, capacitors, or other circuits or components. The electronic device can provide a magnetic field that is modulated by NFC coil  250 . This modulation can be used by the electronic device to identify wireless charger  100 . The identity of wireless charger  100  can inform the electronic device as to power level and other capabilities of wireless charger  100 . 
     Additional ferritic shielding  245  can be placed around board  270  to further improve the shielding of coil  230 . Ferritic shielding  245  can also shield control circuitry  272  on board  270 . 
     Wireless charging assembly  200  can include some of all of these components. Wireless charging assembly can include additional components. For example, an e-shield (not shown) can be placed over coil  230 , between coil  230  and cap  210  of wireless charging assembly  200 . The e-shield can be formed of a layer of copper or other conductive material to intercept electric fields between coil  230  in wireless charging assembly  200  and a corresponding coil in the electronic device. The e-shield can have a low magnetic permeability to pass magnetic fields between coil  230  and the corresponding coil. The e-shield can include breaks to prevent the formation of eddy currents. 
     Attachment portion  222  can be soldered or spot or laser welded to enclosure  220  and first end  422  of stem  420  (shown in  FIG.  2   ) to secure wireless charging assembly  200  to hinge  400 . Further details of hinge  400  are shown in the following figures. 
       FIG.  4 A  and  FIG.  4 B  illustrate a hinge according to an embodiment the present invention. Hinge  400  can allow wireless charging assembly  200  (shown in  FIG.  2   ) to move between an up position, where wireless charging assembly  200  is outside of base  300  (shown in  FIG.  2   ), and a down position, where wireless charging assembly  200  is housed in base  300 . To more securely hold an electronic device (not shown) in place, it can be desirable that hinge  400  provide friction or resistance to wireless charging assembly  200  moving to the down position. This can prevent the weight of the electronic device from inadvertently closing wireless charger  100 . It can also be desirable to allow a user to readily move wireless charging assembly  200  to the up position where it can be mated with the electronic device. Accordingly, embodiments of the present invention can provide a hinge  400  having an asymmetric friction ratio, where the friction incurred in moving wireless charging assembly  200  to the down position is higher than the friction incurred in moving wireless charging assembly  200  to the up position. 
     Hinge  400  can include support blocks  410  supporting stem  420 . Support blocks  410  can be fastened to base  300  as shown in  FIG.  2   . Stem  420  can terminate at first end  422  and can include sleeve  430 . Sleeve  430  can support shafts  440  (shown in  FIG.  5   .) Shafts  440  can support friction clips, such as friction clips  450 . 
       FIG.  4 B  illustrates a side view of a friction clip  450 . Friction clips  450  can be formed of one clip, or several clips placed in parallel. For example, 15, 10, 20, or other numbers of clips can be placed in parallel. Friction clip  450  can include a loop portion  452  placed around shaft  440 , where loop portion  452  includes an end terminating in tab  454 . Tab  454  can be fit into a slot  414  (shown in  FIG.  5   ) of support blocks  410 . As wireless charging assembly  200  moves to the up position, shaft  440  can rotate in a counterclockwise direction as shown. This action can act to loosen loop portion  452  from shaft  440 , thereby allowing wireless charging assembly  200  to readily move to the up position. When wireless charging assembly  200  is moved to the down position, shaft  440  can rotate in a clockwise direction as drawn. This can act to tighten loop portion  452  around shaft  440 , thereby increasing a resistance to the downward motion of wireless charging assembly  200 . Further details of hinge  400  are shown in the following figure. 
       FIG.  5    is an exploded diagram of a hinge according to an embodiment of the present invention. Hinge  400  can include support blocks  410 . Support blocks  410  can be attached to base  300  (shown in  FIG.  2   ) using fasteners  412 . Support blocks  410  can include slots  414  for accepting tabs  454  on friction clips  450 . Stem  420  can include a U-shaped portion  424  terminating in first end  422 , where first end  422  can be soldered or otherwise attached to wireless charging assembly  200  (shown in  FIG.  2   .) Stem  420  can further include sleeve  430  having a cylindrical opening  432  at a first end and a cylindrical opening  434  at a second end. Shafts  440  can be inserted into cylindrical opening  432  and cylindrical opening  434 . Shafts  440  can be fixed to sleeve  430  by welding, soldering, or other step. Washers  470  and end caps  480  can also be inserted on shafts  440 . Wire  500  (shown in  FIG.  3   ) can be routed through sleeve  430  and channel  426  in stem  420  to wireless charging assembly  200  (shown in  FIG.  2   .) Wire  500  can be protected and hidden from view by cover  428 . 
     It can be desirable for wireless charging assembly  200  to have a top surface that is level with a top surface of base  300  when wireless charging assembly  200  is in the down position. That is, it can be desirable for wireless charging assembly  200  to properly align with base  300  when wireless charger  100  is closed. Accordingly, stop  490  can be used. Stop  490  can be soldered or spot or laser welded to sleeve  430 . For example, during assembly, wireless charging assembly  200  can be properly aligned with base  300 . Stop  490  can be positioned such that surface  492  of stop  490  is on sleeve  430  and surface  494  of stop  490  is flush against an inside surface of base  300 . Once positioned in this way, stop  490  can be attached to sleeve  430  by soldering, spot or laser welding, or other technique. In this configuration, stop  490  can consistently position wireless charging assembly  200  properly in base  300  when wireless charging assembly  200  is in the down position and wireless charger  100  is closed. 
       FIG.  6    illustrates another hinge according to an embodiment of the present invention. In this example, wrapped spring  620  can be wrapped around a portion of shaft  440 . Wrapped spring  460  can include a first end  622  attached to support block  410 . As before, when wireless charging assembly  200  is moved to the up position, stem  420  can rotate upwards. This can act to loosen wrapped spring  620  from around shaft  440 , thereby making it easier to move wireless charging assembly  200  to the up position. As wireless charging assembly  200  is moved to the down position, stem  420  can rotate downwards, which can act to tighten wrapped spring  620  around shaft  440 , thereby increasing a resistance to this movement. Wrapped spring  620  can encircle shaft  440  various numbers of times in various embodiments of the present invention. Wrapped spring  620  can taper towards a second end away from first end  622 . 
       FIG.  7 A  and  FIG.  7 B  illustrate another hinge according to an embodiment of the present invention. In this example, shaft  740  can include a number of slots  742 . Bearings  744  can be placed in slots  742 . Bearings  744  can be spherical, cylindrical, or they can have another shape. Bearings  744  can be biased. For example, they can be biased by springs  746 . A first end of shaft  740 , bearings  744 , and springs  746  can be inserted in boot  750 , while a second end of shaft  740  can be inserted into and attached to sleeve  430 , for example by soldering, laser or spot welding, or other technique. As wireless charging assembly  200  is moved to the up position, stem  420  can rotate upward and shaft  740  can rotate counter-clockwise as shown in  FIG.  7 B . This rotation can drive bearings  744  further back in their slots  742  against springs  746 , thereby allowing wireless charging assembly  200  to move with only limited resistance. As wireless charging assembly  200  is moved to the down position, stem  420  can rotate downward and shaft  740  can rotate clockwise as shown in  FIG.  7 B . This rotation can push bearings into the inside surface of boot  750 , thereby increasing the resistance of the downward motion of wireless charging assembly  200 . 
     The hinges shown in  FIG.  6    and  FIG.  7    can include structures such as stop  490  for hinge  400 , as shown in  FIG.  5   . Again, stop  490  can help to ensure that wireless charging assembly  200  is aligned with base  300  when wireless charging assembly  200  is in the down position. These and other embodiments of the present invention can provide other alignment features to ensure that wireless charging assembly  200  is properly aligned with base  300  when wireless charging assembly  200  is in the down position and wireless charger  100  is closed. Examples are shown in the following figures. 
       FIG.  8    illustrates a side view of a portion of a wireless charger according to an embodiment of the present invention. Wireless charger  100  can include wireless charging assembly  200  and base  300 . Magnet  201  can be located in wireless charging assembly  200 , while magnet  301  can be located in base  300 . As shown, the north end of magnet  201  can be attracted to the south end of magnet  301 . In this way, the magnetic fields generated by magnet  201  and magnet  301  can help to ensure that wireless charging assembly  200  is properly aligned with base  300  when wireless charging assembly  200  is in the down position. That is, the magnet attraction between magnet  201  and magnet  301  can help to align top surface  204  of wireless charging assembly  200  to top surface  304  of base  300  such that top surface  204  is parallel to top surface  304  when wireless charging assembly  200  is in the down position and wireless charger  100  is closed. 
       FIG.  9    illustrates an underside view of a wireless charger according to an embodiment of the present invention. Wireless charging assembly  200  can be attached to base  300  by hinge  400  to form wireless charger  100 . Wireless charging assembly  200  can include magnets  201  that can align with magnets  301  in base  300 . Magnets  301  can be covered by foot  390 . The polarities of each of the magnets  201  and each of the magnets  301  can alternate to increase magnetic fields. For example, magnet  201  in wireless charging assembly  200  can have an opposite polarity as adjacent magnet  202  in wireless charging assembly  200 . Similarly, magnet  301  in base  300  can have an opposite polarity as adjacent magnet  302  in base  300 . Magnet  201  and magnet  202 , and the other corresponding magnets, can be positioned away from hinge  400 . Magnets can also be omitted to provide space for connector receptacle  510 . Cable  600  can include connector insert  610 , which can be inserted into connector receptacle  510 . 
       FIG.  10    illustrates a portion of a wireless charger according to an embodiment of the present invention. Wireless charger  100  can include wireless charging assembly  200  and base  300 . Base  300  can include step  305 . Step  305  can house magnet  301 . The south pole of magnet  301  can be attracted to the north pole of magnet  201  in wireless charging assembly  200 , thereby helping to keep wireless charging assembly  200  properly closed when wireless charging assembly  200  is in the down position. That is, the magnet attraction between magnet  201  and magnet  301  can help to align top surface  204  of wireless charging assembly  200  to top surface  304  of base  300  such that top surface  304  is parallel to top surface  304  when wireless charging assembly  200  is in the down position and wireless charger  100  is closed. 
       FIG.  11    illustrates a wireless charger according to an embodiment of the present invention. Wireless charger  100  can include wireless charging assembly  200  and base  300  attached by hinge  400 . Magnet  201  and magnet  202  can be located in wireless charging assembly  200 , while magnet  301  and magnet  302  can be housed in base  300 . The polarities of magnets  201  and  301  can alternate to increase magnetic fields. For example, magnet  201  in wireless charging assembly  200  can have an opposite polarity as magnet  202  in wireless charging assembly  200 . Similarly, magnet  301  in base  300  can have an opposite polarity as magnet  302  in base  300 . Magnet  201  and magnet  202 , and the other corresponding magnets, can be positioned away from hinge  400 . Magnet  301  can be partially located under magnet  201 , thereby helping to save space in base  300 . This saved space can allow the use of magnets near connector receptacle  510 . Cable  600  can include connector insert  610 , which can be inserted into connector receptacle  510 . 
       FIG.  12    illustrates a connector insert that can be inserted into a receptacle in a wireless charger according to an embodiment of the present invention. Connector insert  610  can be formed at an end of cable  600 . Connector insert  610  can include strain relief  602 , molded portion  630 , and boot  640 . Boot  640  can house EMI shield  650 . EMI shield  650  can house board  660  which can include contacts (not shown) housed in shield  690 . Connector receptacle  510  can include EMI plates  570 , which can further improve shielding of a connection between connector insert  610  and connector receptacle  510 . Front plate  580  can be located at an opening (not shown) in base  300  (shown in  FIG.  2   ) for connector receptacle  510 . 
     In the above examples, hinge  400  can rotate about shaft  440 . Shaft  440  can be located in base  300 . As a result, wireless charging assembly  200  has limited clearance over base  300 . But in some circumstances, it can be desirable to increase this clearance. Increasing this clearance can allow wireless charging assembly  200  to mate with an electronic device (not shown) while the electronic device is in a portrait orientation. Accordingly, it can be desirable for a hinge to rotate about a center that is outside of a base. An example is shown in the following figures. 
       FIG.  13    illustrates a hinge according to an embodiment of the present invention. Hinge  1400  can slide in passage  1430  in base  1300 . Hinge  1400  can include two sliders. Specifically, hinge  1400  can include a fixed or static slider  1410  and a moving slider  1420 . Hinge  1400  can rotate upwards until moving slider  1420  engages static slider  1410 . Hinge  1400  can rotate downwards until moving slider  1420  reaches an end of passage  1430 . In this example, hinge  1400  rotates about a point that is outside of base  1300 . This can increase a clearance between base  1300  and a wireless charging assembly  1200  (shown in  FIG.  14 B ) attached to hinge  1400 . Increasing this clearance can allow an electronic device (not shown) to attach to wireless charging assembly  1200  in a portrait mode. 
       FIG.  14 A  and  FIG.  14 B  illustrate the movement of the hinge of  FIG.  13   . In  FIG.  14 A , hinge  1400  can include static slider  1410  and moving slider  1420  housed in base  1300 . Hinge  1400  can be attached to wireless charging assembly  1200 . Wireless charging assembly  1200  can be in a down position in this configuration. 
     In  FIG.  14 B , hinge  1400  can move through passage  1430  until moving slider  1420  engages static slider  1410 . This can move wireless charging assembly  1200  up and away from base  1300 . This clearance can be sufficient to allow an electronic device (not shown) to attach to wireless charging assembly  1200  in a portrait mode. 
     In these and other embodiments of the present invention, wireless chargers having other types of wireless charging assemblies, hinges, and bases can be implemented. These various wireless chargers can have different form factors, different appearances when closed, different appearances when open, as well as different functionalities. Examples are shown in the following figures. 
       FIG.  15    illustrates a wireless charger according to an embodiment of the present invention. In this example, wireless charger  1500  can include a wireless charging assembly  1520 , base  1530 , and hinge  1540 . Hinge  1540  can fold into the base  1530  such that wireless charging assembly  1520  can reside on a top of base  1530 . This can provide a compact arrangement for transport. Further details of this wireless charger are shown in the following figures. Wireless charging assembly  1520  can the same or similar to wireless charging assembly  200  (shown in  FIG.  2   ) and the other wireless charging assemblies shown herein. 
       FIG.  16    is an exploded view of the wireless charger of  FIG.  15   . In this example, wireless charger  1500  can include a wireless charging assembly  1520  having a top enclosure  1522  and the bottom enclosure  1524 . Top enclosure  1522  and bottom enclosure  1524  can form an enclosure similar to the enclosure for wireless charger  100 . Wireless charging assembly  1520  can house a magnet array, coil, ferrite, and other components as shown in the other examples herein. Hinge  1540  can connect wireless charging assembly  1520  to base  1530 . Covers  1561  can cover edges of hinge  1540 . Base  1530  can include recess  1532  into which hinge  1540  can be folded to provide a compact arrangement for wireless charger  1500  when it is in the closed configuration. Further details of hinge  1540  are shown in the following figure. 
       FIG.  17    illustrates a hinge for use in the wireless charger of  FIG.  15   . Hinge  1540  can be attached to a bottom of recess  1532  in base  1530  (shown in  FIG.  16   ) using bottom anchor  1534 . Hinge  1540  can be attached to a back side of bottom enclosure  1524  (shown in  FIG.  16    using top anchor  1526 . Hinge  1540  can include mounts  1541  and  1548  as well as housing  1544 . Shafts  1543  can attach mount  1541  to housing  1544  and shafts  1545  can attach mount  1548  to housing  1544 . Specifically, ribbed portions  1547  of shafts  1543  and shafts  1545  can be inserted into and form an interference fit with opening  1537  in bottom anchor  1534  and opening  1527  in top anchor  1526 . Pins  1550  in housing  1544  can be fit in openings  1549  in mounts  1541  and  1548 . Friction clips  1542  can be placed around shafts  1543 . Tabs  1552  can be fit into slots  1551  in mount  1541 . Friction clips  1542  can increase a resistance to a movement of wireless charging assembly  1520  (shown in  FIG.  15   ) to a down position relative to a resistance to a movement of wireless charging assembly  1520  to an up position. Friction clips can be the same or similar to friction clips  450  (shown in  FIG.  4   .) Shafts  1545  can further include stops  1546  that can limit a movement of hinge  1540 . Covers  1561  (shown in  FIG.  16   ) can cover openings  1549  in mounts  1548  and  1541 . 
       FIG.  18 A  and  FIG.  18 B  illustrate another wireless charger according to an embodiment of the present invention. Wireless charger  1800  can fold to a compact shape as shown in  FIG.  18 A . Wireless charger  1800  can include a wireless charging assembly  1820  supported by top piece  1822 . Wireless charging assembly  1820  can the same or similar to wireless charging assembly  200  (shown in  FIG.  2   ) and the other wireless charging assemblies shown herein. Hinge  1840  can connect top piece  1822  and base  1830 . Top piece  1822 , hinge  1840 , and base  1830  can be formed of metal plates that are forced together and have an interference fit. These plates can be covered with soft goods such as a fabric, leather, or other natural or manufactured material. Power can be provided to wireless charging assembly  1820  via cable  1860 . 
       FIGS.  19 A  and  FIG.  19 B  illustrate another wireless charger according to an embodiment of the present invention. Wireless charger  1900  can again fold into a very compact shape. Wireless charger  1900  can include base  1930  and wireless charging assembly  1920  supported by top piece  1922 . Top piece  1922  and base  1930  can be joined by hinge  1940 . Hinge  1940  can be joined to top piece  1922  through rod  1942  and to base  1930  through rod  1944 . Power can be provided to wireless charging assembly  1920  via cable  1960 . Wireless charging assembly  1920  can the same or similar to wireless charging assembly  200  (shown in  FIG.  2   ) and the other wireless charging assemblies shown herein. 
       FIG.  20    illustrates another wireless charger according to an embodiment of the present invention. In this example, wireless charger  2000  can be put on be formed from stamped and bent stainless steel or other material. Wireless charger  2000  can include wireless charging assembly  2020  and base  2030  joined by hinge portion  2040 . Wireless charging assembly  2020  can the same or similar to wireless charging assembly  200  (shown in  FIG.  2   ) and the other wireless charging assemblies shown herein. 
     In these examples, wireless chargers tend to have a squared off base and a linear hinge. It can also be desirable to have different shaped bases for various functional and aesthetic reasons. For example, it can be desirable to have a thin circular base. However, it can be difficult to implement a hinge on such a base. An example is shown in the following figures. 
       FIG.  21    is an exploded view of a wireless charger according to an embodiment of the present invention. Wireless charger  2100  can include wireless charging assembly  2120 , base  2130  supported by foot  2138 , and hinge  2140  joining base  2130  to wireless charging assembly  2120 . 
     Wireless charging assembly  2120  can be the same or similar to wireless charging assembly  200  (shown in  FIG.  2   ) and the other wireless charging assemblies shown herein. In this example, wireless charging assembly  2120  can include an elastomer ring  2122 , a glass or plastic center  2124 , top housing  2125 , magnet array  2126 , and bottom housing  2128 . Charging coils, and NFC circuits, and other components can be included as well and are not shown for clarity. Base  2130  can be a narrow ring supported by a foot  2138  formed by silicone layer  2139  and support layer  2137 . Further details of hinge  2140  and associated structures are shown in the following figure. 
       FIG.  22    illustrates a hinge for the wireless charger of  FIG.  21   . Hinge  2140  can be a rod formed of nitinol (an alloy of nickel and titanium.) Nitinol has the property that it can bend while being able to return to its original shape. This can allow stem  2142  to be attached to hinge  2140  and move relative to base  2130 , even though hinge  2140  is curved to match a portion of the circumference of base  2130 . Hinge  2140  can be protected by silicone pad  2210  and held in place by compression block  2220  and support block  2250 . Silicone pad  2210  can allow hinge  2140  to rotate with limited wear from compression block  2220 . Fasteners  2230  and fasteners  2240  can hold compression block  2220  and support block  2250  in place. 
       FIG.  23    illustrates a portion of the wireless charger of  FIG.  21   . In this example, a portion of base  2130  can include a groove  2131 . Groove  2131  can be used to house a nitinol shaft utilized as hinge  2140  as shown in  FIG.  22   . 
     Again, in some circumstances it can be desirable to increase a clearance between a wireless charging assembly and a base of a wireless charger. This can allow the wireless charger to hold an electronic device in the portrait position, amongst other possible benefits. Examples are shown in the following figures. 
       FIG.  24    illustrates a wireless charger according to an embodiment of the present invention. In this example, wireless charging assembly  2420  of wireless charger  2400  can attach to base  2430  through hinge  2440 . Hinge  2440  can include a telescoping portion  2442  that can be extended to increase a height of wireless charging assembly  2420  relative to base  2430 . Wireless charging assembly  2420  can the same or similar to wireless charging assembly  200  (shown in  FIG.  2   ) and the other wireless charging assemblies shown herein. 
       FIG.  25 A  and  FIG.  25 B  illustrates another wireless charger according to an embodiment of the present invention. Wireless charger  2500  can include base  2530  and wireless charging assembly  2520 . Wireless charging assembly  2520  can telescope through two positions, shown as  2520 A and  2520 B. Wireless charging assembly  2520  can be attached to base  2530  via hinge  2540 . Examples of how this telescoping can operate are shown in the following figures. 
       FIG.  26 A  and  FIG.  26 B  illustrate a telescoping mechanism according to an embodiment of the present invention. Wireless charger  2500  can include wireless charging assembly  2520 . Wireless charging assembly  2520  can the same or similar to wireless charging assembly  200  (shown in  FIG.  2   ) and the other wireless charging assemblies shown herein. Wireless charging assembly  2520  can move along hinge  2540  from a down position showed in  FIG.  26 A  to an up position shown in  FIG.  26 B . This telescoping mechanism can include a rack and pinion including rack  2544 , which can be located on a backside of wireless charging assembly  2520 . The telescoping mechanism can further include a pinion including axel  2542  and gears  2546 . Axel  2542  and gears  2546  can be located on hinge  2540 , which can join wireless charging assembly  2520  to base  2530 . Rack  2544  and the pinion including axel  2542  gears  2546  can be formed by electrical discharge machining (EDM) or other procedure. As wireless charging assembly  2520  is moved, axel  2542  can rotate, and gears  2546  can mesh with gears on rack  2544 . 
       FIG.  27 A  and  FIG.  27 B  illustrates another telescoping mechanism according to an embodiment of the present invention. In this example, wireless charger  2500  can include arms  2742  that can be used to position wireless charging assembly  2520  relative to hinge  2540 . Wireless charging assembly  2520  can move from a down position as shown in  FIG.  27 A  to an up position as shown in  FIG.  27 B . As this movement occurs, intersection  2743  of arms  2742  can travel in slot  2746 . Slot  2746  can keep wireless charging assembly  2520  aligned with hinge  2540  through its travel. Slots  2744  can allow arms  2742  to flatten and reverse direction throughout the movement of wireless charging assembly  2520 . 
     In these and other embodiments of the present invention, it can be desirable to raise and lower a wireless charging assembly of a wireless charger relative to its base. It may also be desirable to be able to the tilt a wireless charging assembly. It can also be desirable that the wireless charger fold to a compact shape for transport. Examples are shown in the following figures. 
       FIG.  28 A  and  FIG.  28 B  illustrate a wireless charger according to an embodiment of the present invention. Wireless charger  2800  can include wireless charging assembly  2820  and base  2830 . Wireless charging assembly  2820  and base and  2830  can be joined by hinge  2840 . Wireless charging assembly  2820  can the same or similar to wireless charging assembly  200  (shown in  FIG.  2   ) and the other wireless charging assemblies shown herein. 
       FIG.  29 A  and  FIG.  29 B  illustrate movements of portions of the wireless charger of  FIG.  28 A  and  FIG.  28 B . Hinge  2840  can move relative to base  2830  as shown in  FIG.  29 A . This can change a clearance of wireless charging assembly  2820  relative to base  2830 . Wireless charging assembly  2820  can further tilt relative to hinge  2840  through a range of motion as shown in  FIG.  29 B . 
       FIG.  30    is an exploded view of the wireless charger of  FIG.  28 A  and  FIG.  28 B . Wireless charger  2800  can include wireless charging assembly  2820 , which can be the same or similar to wireless charging assembly  200  (shown in  FIG.  2   .) Wireless charging assembly  22820  can include friction pad  2821 , which may be formed of silicone or other material, attached to a front of plastic cap  2822 . Plastic cap  2822  can be attached to support plate  2828  to form an enclosure for magnet array  2824 , DC shield  2827 , and coil and ferrite  2826 . 
     Hinge  2840  can be attached to a back surface of support plate  2828  by attachment lugs and fasteners  2842 . Wireless charging assembly  2820  can rotate about hinge  2840  at upper shaft  2844 . Hinge  2840  can rotate about base  2830  at lower shaft  2834 , which can be held in place by cowling and fasteners  2832 . Friction screws  2845  can be used to adjust the resistance of movement of wireless charging assembly  2820  relative to hinge  2840 . Friction screws  2846  can be used to adjust the resistance movement of hinge  2840  relative to base  2830 . Pressure to upper shaft  2844  and lower shaft  2834  can be adjusted by turning friction screws  2845  and friction screws  2846  respectively. 
       FIG.  31 A  and  FIG.  31 B  illustrate a wireless charger according to an embodiment of the present invention. Wireless charger  3100  can fold into a compact shape as shown in  FIG.  31 A . Wireless charger  3100  can include wireless charging assembly  3120  and base  3130  joined by hinge  3140 . Wireless charging assembly  3120  can the same or similar to wireless charging assembly  200  (shown in  FIG.  2   ) and the other wireless charging assemblies shown herein. 
       FIG.  32 A  and  FIG.  32 B  illustrate movements of portions of the wireless charger of  FIG.  31 A  and  FIG.  31 B . Wireless charging assembly  3120  can tilt relative to hinge  3140  through a range of motion as shown in  FIG.  32 A . Hinge  3140  can move relative to base  3130  as shown in  FIG.  32 B . This can change a clearance of wireless charging assembly  3120  relative to base  3130 . 
       FIG.  33    is an exploded view of the wireless charger of  FIG.  31 A  and  FIG.  31 B . Wireless charging assembly  3120  of wireless charger  3100  can include friction pad  3122 , which can be formed of silicone or other material, attached to a front of plastic cap  3123 . Plastic cap  3123  can be attached to support plate  3128  to form an enclosure for magnet array  3124 , DC shield  3127 , and coil and ferrite  3126 . 
     Hinge  3140  can be attached to a back surface of support plate  3128  by attachment lug  3144 . Wireless charging assembly  3120  and attachment lug  3144  can tilt relative to bracket  3145  as shown by the movement in  FIG.  32 A . Bracket  3145  can rotate about hinge  3140  at upper shafts  3143 . Hinge  3140  can rotate about base  3130  at lower shafts  3142 , which can be secured in base  3130 . This movement can be seen in  FIG.  32 B . Base  3130  can reside on silicone or other pad  3139 . Spring  3141  can provide tension for hinge  3140 . 
       FIG.  34 A  and  FIG.  34 B  illustrate a wireless charger according to an embodiment of the present invention. Wireless charger  3400  can fold into a compact shape as shown in  FIG.  34 A . Wireless charger  3400  can include wireless charging assembly  3420  and base  3430 , which can be connected together through hinge  3440 . Wireless charging assembly  3420  can the same or similar to wireless charging assembly  200  (shown in  FIG.  2   ) and the other wireless charging assemblies shown herein. 
       FIG.  35 A  and  FIG.  35 B  illustrate the wireless charger of  FIG.  34 A  and  FIG.  34 B . Wireless charger  3400  can include wireless charging assembly  3420  and base  3430 , which can be connected together through hinge  3440 . 
     Again, the various magnet arrays shown herein can be fixed in place, or they can be movable between a first position and a second position. Examples of fixed magnet arrays that can be used for these magnet arrays are shown in the following figures. 
     Described herein are various embodiments of magnetic alignment systems and components thereof. A magnetic alignment system can include annular alignment components comprising a ring of magnets having a particular magnetic orientation or pattern of magnetic orientations such that a “primary” annular alignment component can attract and hold a complementary “secondary” annular alignment component. In some embodiments described below, the primary annular alignment component is assumed to be in a wireless charging device, surrounding an inductive charging coil, while the secondary annular alignment component is assumed to be in a portable electronic device, surrounding a receiver coil that can receive power from the inductive charging coil of the wireless charging device. Many variations are possible; for instance, a “primary” annular alignment component can be in a portable electronic device while a “secondary” annular alignment component can be in a wireless charging device. Also described herein is an “auxiliary” annular alignment component that is complementary to the primary and secondary annular alignment components such that one surface of the auxiliary annular alignment component is attracted to the primary alignment component while the opposite surface is attracted to the secondary alignment component. An auxiliary annular alignment component can be disposed, e.g., in a case for a portable electronic device. 
     In some embodiments, a magnetic alignment system can also include a rotational alignment component that facilitates aligning two devices in a preferred rotational orientation. It should be understood that any device that has an annular alignment component might or might not also have a rotational alignment component. 
     In some embodiments, a magnetic alignment system can also include an near-field communication (NFC) coil and supporting circuitry to allow devices to identify themselves to each other using an NFC protocol. NFC coils can be disposed inboard of the annular alignment component or outboard of the annular alignment component. It should be understood that an NFC component is optional in the context of providing magnetic alignment. 
       FIG.  36    shows a simplified representation of a wireless charging system  3600  incorporating a magnetic alignment system  3606  according to some embodiments. A portable electronic device  3604  is positioned on a charging surface  3608  of a wireless charging device  3602 . Portable electronic device  3604  can be a consumer electronic device, such as a smart phone, tablet, wearable device, or the like, or any other electronic device for which wireless charging is desired. Wireless charging device  3602  can be any device that is configured to generate time-varying magnetic flux to induce a current in a suitably configured receiving device. For instance, wireless charging device  3602  can be any of the wireless chargers herein, a wireless charging mat, puck, docking station, or the like. Wireless charging device  3602  can include or have access to a power source such as battery power or standard AC power. 
     To enable wireless power transfer, portable electronic device  3604  and wireless charging device  3602  can include inductive coils  3610  and  3612 , respectively, which can operate to transfer power between them. For example, inductive coil  3612  can be a transmitter coil that generates a time-varying magnetic flux  3614 , and inductive coil  3610  can be a receiver coil in which an electric current is induced in response to time-varying magnetic flux  3614 . The received electric current can be used to charge a battery of portable electronic device  3604 , to provide operating power to a component of portable electronic device  3604 , and/or for other purposes as desired. (“Wireless power transfer” and “inductive power transfer,” as used herein, refer generally to the process of generating a time-varying magnetic field in a conductive coil of a first device that induces an electric current in a conductive coil of a second device.) 
     To enable efficient wireless power transfer, it is desirable to align inductive coils  3612  and  3610 . According to some embodiments, magnetic alignment system  3606  can provide such alignment. In the example shown in  FIG.  36   , magnetic alignment system  3606  includes a primary magnetic alignment component  3616  disposed within or on a surface of wireless charging device  3602  and a secondary magnetic alignment component  3618  disposed within or on a surface of portable electronic device  3604 . Primary alignment components  3616  and secondary alignment components  3618  are configured to magnetically attract one another into an aligned position in which inductive coils  3610  and  3612  are aligned with one another to effectuate wireless power transfer. 
     Primary alignment components  3616  can be sued as magnet array  260  (shown in  FIG.  2   ) or as any of the other magnet arrays shown herein or otherwise provided by embodiments of the present invention. 
     According to embodiments described herein, a magnetic alignment component (including a primary or secondary alignment component) of a magnetic alignment system can be formed of arcuate magnets arranged in an annular configuration. In some embodiments, each magnet can have its magnetic polarity oriented in a desired direction so that magnetic attraction between the primary and secondary magnetic alignment components provides a desired alignment. In some embodiments, an arcuate magnet can include a first magnetic region with magnetic polarity oriented in a first direction and a second magnetic region with magnetic polarity oriented in a second direction different from (e.g., opposite to) the first direction. As will be described, different configurations can provide different degrees of magnetic field leakage. 
       FIG.  37 A  shows a perspective view of a magnetic alignment system  3700  according to some embodiments, and  FIG.  37 B  shows a cross-section through magnetic alignment system  3700  across the cut plane indicated in  FIG.  37 A . Magnetic alignment system  3700  can be an implementation of magnetic alignment system  3606  of  FIG.  36   . In magnetic alignment system  3700 , the alignment components all have magnetic polarity oriented in the same direction (along the axis of the annular configuration). For convenience of description, an “axial” direction (also referred to as a “longitudinal” or “z” direction) is defined to be parallel to an axis of rotational symmetry  3701  of magnetic alignment system  3700 , and a transverse plane (also referred to as a “lateral” or “x” or “y” direction) is defined to be normal to axis  3701 . The term “proximal side” is used herein to refer to a side of one alignment component that is oriented toward the other alignment component when the magnetic alignment system is aligned, and the term “distal side” is used to refer to a side opposite the proximal side. 
     As shown in  FIG.  37 A , magnetic alignment system  3700  can include a primary alignment component  3716  (which can be an implementation of primary alignment component  3616  of  FIG.  36   ) and a secondary alignment component  3718  (which can be an implementation of secondary alignment component  3618  of  FIG.  36   ). Primary alignment component  3716  and secondary alignment component  3718  have annular shapes and may also be referred to as “annular” alignment components. The particular dimensions can be chosen as desired. In some embodiments, primary alignment component  3716  and secondary alignment component  3718  can each have an outer diameter of about 404 mm and a radial width of about 6 mm. The outer diameters and radial widths of primary alignment component  3716  and secondary alignment component  3718  need not be exactly equal. For instance, the radial width of secondary alignment component  3718  can be slightly less than the radial width of primary alignment component  3716  and/or the outer diameter of secondary alignment component  3718  can also be slightly less than the radial width of primary alignment component  3716  so that, when in alignment, the inner and outer sides of primary alignment component  3716  extend beyond the corresponding inner and outer sides of secondary alignment component  3718 . Thicknesses (or axial dimensions) of primary alignment component  3716  and secondary alignment component  3718  can also be chosen as desired. In some embodiments, primary alignment component  3716  has a thickness of about 1.5 mm while secondary alignment component  3718  has a thickness of about 0.37 mm. 
     Primary alignment component  3716  can include a number of sectors, each of which can be formed of one or more primary arcuate magnets  3726 , and secondary alignment component  3718  can include a number of sectors, each of which can be formed of one or more secondary arcuate magnets  3728 . In the example shown, the number of primary magnets  3726  is equal to the number of secondary magnets  3728 , and each sector includes exactly one magnet, but this is not required. Primary magnets  3726  and secondary magnets  3728  can have arcuate (or curved) shapes in the transverse plane such that when primary magnets  3726  (or secondary magnets  3728 ) are positioned adjacent to one another end-to-end, primary magnets  3726  (or secondary magnets  3728 ) form an annular structure as shown. In some embodiments, primary magnets  3726  can be in contact with each other at interfaces  3730 , and secondary magnets  3728  can be in contact with each other at interfaces  3732 . Alternatively, small gaps or spaces may separate adjacent primary magnets  3726  or secondary magnets  3728 , providing a greater degree of tolerance during manufacturing. 
     In some embodiments, primary alignment component  3716  can also include an annular shield  3714  disposed on a distal surface of primary magnets  3726 . In some embodiments, shield  3714  can be formed as a single annular piece of material and adhered to primary magnets  3726  to secure primary magnets  3726  into position. Shield  3714  can be formed of a material that has high magnetic permeability, such as stainless steel, and can redirect magnetic fields to prevent them from propagating beyond the distal side of primary alignment component  3716 , thereby protecting sensitive electronic components located beyond the distal side of primary alignment component  3716  from magnetic interference. 
     Primary magnets  3726  and secondary magnets  3728  can be made of a magnetic material such as an NdFeB material, other rare earth magnetic materials, or other materials that can be magnetized to create a persistent magnetic field. Each primary magnet  3726  and each secondary magnet  3728  can have a monolithic structure having a single magnetic region with a magnetic polarity aligned in the axial direction as shown by magnetic polarity indicators  3715 ,  3717  in  FIG.  37 B . For example, each primary magnet  3726  and each secondary magnet  3728  can be a bar magnet that has been ground and shaped into an arcuate structure having an axial magnetic orientation. (As will be apparent, the term “magnetic orientation” refers to the direction of orientation of the magnetic polarity of a magnet.) In the example shown, primary magnet  3726  has its north pole oriented toward the proximal surface and south pole oriented toward the distal surface while secondary magnet  3728  has its south pole oriented toward the proximal surface and north pole oriented toward the distal surface. In other embodiments, the magnetic orientations can be reversed such that primary magnet  3726  has its south pole oriented toward the proximal surface and north pole oriented toward the distal surface while secondary magnet  3728  has its north pole oriented toward the proximal surface and south pole oriented toward the distal surface. 
     As shown in  FIG.  37 B , the axial magnetic orientation of primary magnet  3726  and secondary magnet  3728  can generate magnetic fields  3740  that generate an attractive force between primary magnet  3726  and secondary magnet  3728 , thereby facilitating alignment between respective electronic devices in which primary alignment component  3716  and secondary alignment component  3718  are disposed (e.g., as shown in  FIG.  36   ). While shield  3714  can redirect some of magnetic fields  3740  away from regions below primary magnet  3726 , magnetic fields  3740  may still propagate to regions laterally adjacent to primary magnet  3726  and secondary magnet  3728 . In some embodiments, the lateral propagation of magnetic fields  3740  may result in magnetic field leakage to other magnetically sensitive components. For instance, if an inductive coil having a ferromagnetic shield is placed in the interior region of annular primary alignment component  3716  (or secondary alignment component  3718 ), leakage of magnetic fields  3740  may saturate the ferrimagnetic shield, which can degrade wireless charging performance. 
     It will be appreciated that magnetic alignment system  3700  is illustrative and that variations and modifications are possible. For instance, while primary alignment component  3716  and secondary alignment component  3718  are each shown as being constructed of eight arcuate magnets, other embodiments may use a different number of magnets, such as sixteen magnets, thirty-six magnets, or any other number of magnets, and the number of primary magnets need not be equal to the number of secondary magnets. In other embodiments, primary alignment component  3716  and/or secondary alignment component  3718  can each be formed of a single, monolithic annular magnet; however, segmenting magnetic alignment components  3716  and  3718  into arcuate magnets may improve manufacturing because smaller arcuate segments are less brittle than a single, monolithic annular magnet and are less prone to yield loss due to physical stresses imposed on the magnetic material during manufacturing. 
     As noted above with reference to  FIG.  37 B , a magnetic alignment system with a single axial magnetic orientation may allow lateral leakage of magnetic fields, which may adversely affect performance of other components of an electronic device. Accordingly, some embodiments provide magnetic alignment systems with reduced magnetic field leakage. Examples will now be described. 
       FIG.  38 A  shows a perspective view of a magnetic alignment system  3800  according to some embodiments, and  FIG.  38 B  shows a cross-section through magnetic alignment system  3800  across the cut plane indicated in  FIG.  38 A . Magnetic alignment system  3800  can be an implementation of magnetic alignment system  3606  of  FIG.  36   . In magnetic alignment system  3800 , the alignment components have magnetic components configured in a “closed loop” configuration as described below. 
     As shown in  FIG.  38 A , magnetic alignment system  3800  can include a primary alignment component  3816  (which can be an implementation of primary alignment component  3616  of  FIG.  36   ) and a secondary alignment component  3818  (which can be an implementation of secondary alignment component  3618  of  FIG.  36   ). Primary alignment component  3816  and secondary alignment component  3818  have annular shapes and may also be referred to as “annular” alignment components. The particular dimensions can be chosen as desired. In some embodiments, primary alignment component  3816  and secondary alignment component  3818  can each have an outer diameter of about 404 mm and a radial width of about 6 mm. The outer diameters and radial widths of primary alignment component  3816  and secondary alignment component  3818  need not be exactly equal. For instance, the radial width of secondary alignment component  3818  can be slightly less than the radial width of primary alignment component  3816  and/or the outer diameter of secondary alignment component  3818  can also be slightly less than the radial width of primary alignment component  3816  so that, when in alignment, the inner and outer sides of primary alignment component  3816  extend beyond the corresponding inner and outer sides of secondary alignment component  3818 . Thicknesses (or axial dimensions) of primary alignment component  3816  and secondary alignment component  3818  can also be chosen as desired. In some embodiments, primary alignment component  3816  has a thickness of about 1.5 mm while secondary alignment component  3818  has a thickness of about 0.37 mm. 
     Primary alignment component  3816  can include a number of sectors, each of which can be formed of a number of primary magnets  3826 , and secondary alignment component  3818  can include a number of sectors, each of which can be formed of a number of secondary magnets  3828 . In the example shown, the number of primary magnets  3826  is equal to the number of secondary magnets  3828 , and each sector includes exactly one magnet, but this is not required; for example, as described below a sector may include multiple magnets. Primary magnets  3826  and secondary magnets  3828  can have arcuate (or curved) shapes in the transverse plane such that when primary magnets  3826  (or secondary magnets  3828 ) are positioned adjacent to one another end-to-end, primary magnets  3826  (or secondary magnets  3828 ) form an annular structure as shown. In some embodiments, primary magnets  3826  can be in contact with each other at interfaces  3830 , and secondary magnets  3828  can be in contact with each other at interfaces  3832 . Alternatively, small gaps or spaces may separate adjacent primary magnets  3826  or secondary magnets  3828 , providing a greater degree of tolerance during manufacturing. 
     In some embodiments, primary alignment component  3816  can also include an annular shield  3814  disposed on a distal surface of primary magnets  3826 . In some embodiments, shield  3814  can be formed as a single annular piece of material and adhered to primary magnets  3826  to secure primary magnets  3826  into position. Shield  3814  can be formed of a material that has high magnetic permeability, such as stainless steel, and can redirect magnetic fields to prevent them from propagating beyond the distal side of primary alignment component  3816 , thereby protecting sensitive electronic components located beyond the distal side of primary alignment component  3816  from magnetic interference. 
     Primary magnets  3826  and secondary magnets  3828  can be made of a magnetic material such as an NdFeB material, other rare earth magnetic materials, or other materials that can be magnetized to create a persistent magnetic field. Each secondary magnet  3828  can have a single magnetic region with a magnetic polarity having a component in the radial direction in the transverse plane (as shown by magnetic polarity indicator  3817  in  FIG.  38 B ). As described below, the magnetic orientation can be in a radial direction with respect to axis  3801  or another direction having a radial component in the transverse plane. Each primary magnet  3826  can include two magnetic regions having opposite magnetic orientations. For example, each primary magnet  3826  can include an inner arcuate magnetic region  3852  having a magnetic orientation in a first axial direction (as shown by polarity indicator  3853  in  FIG.  38 B ), an outer arcuate magnetic region  3854  having a magnetic orientation in a second axial direction opposite the first direction (as shown by polarity indicator  3855  in  FIG.  38 B ), and a central non-magnetized region  3856  that does not have a magnetic orientation. Central non-magnetized region  3856  can magnetically separate inner arcuate region  3852  from outer arcuate region  3854  by inhibiting magnetic fields from directly crossing through central region  3856 . Magnets having regions of opposite magnetic orientation separated by a non-magnetized region are sometimes referred to herein as having a “quad-pole” configuration. 
     In some embodiments, each secondary magnet  3828  can be made of a magnetic material that has been ground and shaped into an arcuate structure, and a magnetic orientation having a radial component in the transverse plane can be created, e.g., using a magnetizer. Similarly, each primary magnet  3826  can be made of a single piece of magnetic material that has been ground and shaped into an arcuate structure, and a magnetizer can be applied to the arcuate structure to induce an axial magnetic orientation in one direction within an inner arcuate region of the structure and an axial magnetic orientation in the opposite direction within an outer arcuate region of the structure, while demagnetizing or avoiding creation of a magnetic orientation in the central region. In some alternative embodiments, each primary magnet  3826  can be a compound structure with two arcuate pieces of magnetic material providing inner arcuate magnetic region  3852  and outer arcuate magnetic region  3854 ; in such embodiments, central non-magnetized region  3856  can be formed of an arcuate piece of nonmagnetic material or formed as an air gap defined by sidewalls of inner arcuate magnetic region  3852  and outer arcuate magnetic region  3854 . 
     As shown in  FIG.  38 B , the magnetic polarity of secondary magnet  3828  (shown by indicator  3817 ) can be oriented such that when primary alignment component  3816  and secondary alignment component  3818  are aligned, the south pole of secondary magnet  3828  is oriented toward the north pole of inner arcuate magnetic region  3852  (shown by indicator  3853 ) while the north pole of secondary magnet  3828  is oriented toward the south pole of outer arcuate magnetic region  3854  (shown by indicator  3855 ). Accordingly, the respective magnetic orientations of inner arcuate magnetic region  3852 , secondary magnet  3828  and outer arcuate magnetic region  3856  can generate magnetic fields  3840  that produce an attractive force between primary magnet  3826  and secondary magnet  3828 , thereby facilitating alignment between respective electronic devices in which primary alignment component  3816  and secondary alignment component  3818  are disposed (e.g., as shown in  FIG.  36   ). Shield  3814  can redirect some of magnetic fields  3840  away from regions below primary magnet  3826 . Further, the “closed-loop” magnetic field  3840  formed around central nonmagnetic region  3856  can have tight and compact field lines that do not stray from primary magnets  3826  and secondary magnets  3828  as far as magnetic field  3740  strays from primary magnets  3726  and secondary magnets  3728  in  FIG.  37 B . Thus, magnetically sensitive components can be placed relatively close to primary alignment component  3816  with reduced concern for stray magnetic fields. Accordingly, as compared to magnetic alignment system  3700 , magnetic alignment system  3800  can help to reduce the overall size of a device in which primary alignment component  3816  is positioned and can also help reduce noise created by magnetic field  3840  in adjacent components or devices, such as a power-receiving device in which secondary alignment component  3818  is positioned. 
     It will be appreciated that magnetic alignment system  3800  is illustrative and that variations and modifications are possible. For instance, while primary alignment component  3816  and secondary alignment component  3818  are each shown as being constructed of eight arcuate magnets, other embodiments may use a different number of magnets, such as sixteen magnets, thirty-six magnets, or any other number of magnets, and the number of primary magnets need not be equal to the number of secondary magnets. In other embodiments, secondary alignment component  3818  can be formed of a single, monolithic annular magnet. Similarly, primary alignment component  3816  can be formed of a single, monolithic annular piece of magnetic material with an appropriate magnetization pattern as described above, or primary alignment component  3816  can be formed of a monolithic inner annular magnet and a monolithic outer annular magnet, with an annular air gap or region of non-magnetic material disposed between the inner annular magnet and outer annular magnet. In some embodiments, a construction using multiple arcuate magnets may improve manufacturing because smaller arcuate magnets are less brittle than a single, monolithic annular magnet and are less prone to yield loss due to physical stresses imposed on the magnetic material during manufacturing. It should also be understood that the magnetic orientations of the various magnetic alignment components or individual magnets do not need to align exactly with the lateral and axial directions. The magnetic orientation can have any angle that provides a closed-loop path for a magnetic field through the primary and secondary alignment components. 
     As noted above, in embodiments of magnetic alignment systems having closed-loop magnetic orientations, such as magnetic alignment system  3800 , secondary alignment component  3818  can have a magnetic orientation in the transverse plane. For example, in some embodiments, secondary alignment component  3818  can have a magnetic polarity in a radial orientation.  FIG.  39    shows a simplified top-down view of a secondary alignment component  3918  according to some embodiments having secondary magnets  3928   a - h  with radial magnetic orientations as shown by magnetic polarity indicators  3917   a - h . In this example, each secondary magnet  3928   a - h  has a north magnetic pole oriented toward the radially outward side and a south magnetic pole toward the radially inward side; however, this orientation can be reversed, and the north magnetic pole of each secondary magnet  3928   a - h  can be oriented toward the radially inward side while the south magnetic pole is oriented toward the radially outward side. 
       FIG.  40 A  shows a perspective view of a magnetic alignment system  4000  according to some embodiments. Magnetic alignment system  4000 , which can be an implementation of magnetic alignment system  3900 , includes a secondary alignment component  4018  having a radially outward magnetic orientation (e.g., as shown in  FIG.  39   ) and a complementary primary alignment component  4016 . In this example, magnetic alignment system  4000  includes a gap  4019  between two of the sectors; however, gap  4019  is optional and magnetic alignment system  4000  can be a complete annular structure. Also shown are components  4002 , which can include, for example an inductive coil assembly or other components located within the central region of primary magnetic alignment component  4016  or secondary magnetic alignment component  4018 . Magnetic alignment system  4000  can have a closed-loop configuration similar to magnetic alignment system  3800  (as shown in  FIG.  38 B ) and can include arcuate sectors  4001 , each of which can be made of one or more arcuate magnets. In some embodiments, the closed-loop configuration of magnetic alignment system  4000  can reduce or prevent magnetic field leakage that may affect components  4002 . 
       FIG.  40 B  shows an axial cross-section view through one of arcuate sectors  4001 . Arcuate sector  4001  includes a primary magnet  4026  and a secondary magnet  4028 . As shown by orientation indicator  4017 , secondary magnet  4028  has a magnetic polarity oriented in a radially outward direction, i.e., the north magnetic pole is toward the radially outward side of magnetic alignment system  4000 . Like primary magnets  3826  described above, primary magnet  4026  includes an inner arcuate magnetic region  4052 , an outer arcuate magnetic region  4054 , and a central non-magnetized region  4056  (which can include, e.g., an air gap or a region of nonmagnetic or non-magnetized material). Inner arcuate magnetic region  4052  has a magnetic polarity oriented axially such that the north magnetic pole is toward secondary magnet  4028 , as shown by indicator  4053 , while outer arcuate magnetic region  4054  has an opposite magnetic orientation, with the south magnetic pole oriented toward secondary magnet  4028 , as shown by indicator  4055 . As described above with reference to  FIG.  38 B , the arrangement of magnetic orientations shown in  FIG.  40 B  results in magnetic attraction between primary magnet  4026  and secondary magnet  4028 . In some embodiments, the magnetic polarities can be reversed such that the north magnetic pole of secondary magnet  4028  is oriented toward the radially inward side of magnetic alignment system  4000 , the north magnetic pole of outer arcuate region  4054  of primary magnet  4026  is oriented toward secondary magnet  4028 , and the north magnetic pole of inner arcuate region  4052  is oriented away from secondary magnet  4028 . 
     When primary alignment component  4016  and secondary alignment component  4018  are aligned, the radially symmetrical arrangement and directional equivalence of magnetic polarities of primary alignment component  4016  and secondary alignment component  4018  allow secondary alignment component  4018  to rotate freely (relative to primary alignment component  4016 ) in the clockwise or counterclockwise direction in the lateral plane while maintaining alignment along the axis. 
     As used herein, a “radial” orientation need not be exactly or purely radial. For example,  FIG.  40 C  shows a secondary arcuate magnet  4038  according to some embodiments. Secondary arcuate magnet  4038  has a purely radial magnetic orientation, as indicated by arrows  4039 . Each arrow  4039  is directed at the center of curvature of magnet  4038 ; if extended inward, arrows  4039  would converge at the center of curvature. However, achieving this purely radial magnetization requires that magnetic domains within magnet  4038  be oriented obliquely to neighboring magnetic domains. For some types of magnetic materials, purely radial magnetic orientation may not be practical. Accordingly, some embodiments use a “pseudo-radial” magnetic orientation that approximates the purely radial orientation of  FIG.  40 C .  FIG.  40 D  shows a secondary arcuate magnet  4048  with pseudo-radial magnetic orientation according to some embodiments. Magnet  4048  has a magnetic orientation, shown by arrows  4049 , that is perpendicular to a baseline  4051  connecting the inner corners  4057 ,  4059  of arcuate magnet  4048 . If extended inward, arrows  4049  would not converge. Thus, neighboring magnetic domains in magnet  4048  are parallel to each other, which is readily achievable in magnetic materials such as NdFeB. The overall effect in a magnetic alignment system, however, can be similar to the purely radial magnetic orientation shown  FIG.  40 C .  FIG.  40 E  shows a secondary annular alignment component  4058  made up of magnets  4048  according to some embodiments. Magnetic orientation arrows  4049  have been extended to the center point  4061  of annular alignment component  4058 . As shown the magnetic field direction can be approximately radial, with the closeness of the approximation depending on the number of magnets  4048  and the inner radius of annular alignment component  4058 . In some embodiments, 138 magnets  4048  can provide a pseudo-radial orientation; in other embodiments, more or fewer magnets can be used. It should be understood that all references herein to magnets having a “radial” magnetic orientation include pseudo-radial magnetic orientations and other magnetic orientations that are approximately but not purely radial. 
     In some embodiments, a radial magnetic orientation in a secondary alignment component  4018  (e.g., as shown in  FIG.  40 B ) provides a magnetic force profile between secondary alignment component  4018  and primary alignment component  4016  that is the same around the entire circumference of the magnetic alignment system. The radial magnetic orientation can also result in greater magnetic permeance, which allows secondary alignment component  4018  to resist demagnetization as well as enhancing the attractive force in the axial direction and improving shear force in the lateral directions when the two components are aligned. 
       FIGS.  41 A and  41 B  show graphs of force profiles for different magnetic alignment systems, according to some embodiments. Specifically,  FIG.  41 A  shows a graph  4100  of vertical attractive (normal) force in the axial (z) direction for different magnetic alignment systems of comparable size and using similar types of magnets. Graph  4100  has a horizontal axis representing displacement from a center of alignment, where 0 represents the aligned position and negative and positive values represent left and right displacements from the aligned position in arbitrary units, and a vertical axis showing the normal force (F NORMAL ) as a function of displacement in arbitrary units. For purposes of this description, F NORMAL  is defined as the magnetic force between the primary and secondary alignment components in the axial direction; F NORMAL &gt;0 represents attractive force while F NORMAL &lt;0 represents repulsive force. Graph  4100  shows normal force profiles for three different types of magnetic alignment systems. A first type of magnetic alignment system uses central alignment components, such as a pair of complementary disc-shaped magnets placed along an axis; a representative normal force profile for a “central” magnetic alignment system is shown as line  4101  (dot-dash line). A second type of magnetic alignment system uses annular alignment components with axial magnetic orientations, e.g., magnetic alignment system  3700  of  FIGS.  37 A and  37 B ; a representative normal force profile for such an annular-axial magnetic alignment system is shown as line  4103  (dashed line). A third type of magnetic alignment system uses annular alignment components with closed-loop magnetic orientations and radial symmetry (e.g., magnetic alignment system  4000  of  FIG.  40   ); a representative normal force profile for a radially symmetric closed-loop magnetic alignment system is shown as line  4105  (solid line.) 
     Similarly,  FIG.  41 B  shows a graph  4120  of lateral (shear) force in a transverse direction for different magnetic alignment systems. Graph  4120  has a horizontal axis representing displacement from a center of alignment using the same convention and units as graph  4100 , and a vertical axis showing the shear force (F SHEAR ) as a function of direction in arbitrary units. For purposes of this description, F SHEAR  is defined as the magnetic force between the primary and secondary alignment components in the lateral direction; F SHEAR &gt;0 represents force toward the left along the displacement axis while F SHEAR &lt;0 represents force toward the right along the displacement axis. Graph  4120  shows shear force profiles for the same three types of magnetic alignment systems as graph  4100 : a representative shear force profile for a central magnetic alignment system is shown as line  4121  (dot-dash line); a representative shear force profile for an annular-axial magnetic alignment system is shown as line  4123  (dashed line); and a representative normal force profile for a radially symmetric closed-loop magnetic alignment system is shown as line  4125  (solid line). 
     As shown in  FIG.  41 A , each type of magnetic alignment system achieves the strongest magnetic attraction in the axial direction when the primary and secondary alignment components are in the aligned position (0 on the horizontal axis), as shown by respective peaks  4111 ,  4113 , and  4115 . While the most strongly attractive normal force is achieved in the aligned positioned for all systems, the magnitude of the peak depends on the type of magnetic alignment system. In particular, a radially-symmetric closed-loop magnetic alignment system (e.g., magnetic alignment system  4000  of  FIG.  40   ) provides stronger magnetic attraction when in the aligned position than the other types of magnetic alignment systems. This strong attractive normal force can overcome small misalignments due to frictional force and can achieve a more accurate and robust alignment between the primary and secondary alignment components, which in turn can provide a more accurate and robust alignment between a portable electronic device and a wireless charging device within which the magnetic alignment system is implemented. 
     As shown in  FIG.  41 B , the strongest shear forces (attractive or repulsive) are obtained when the primary and secondary alignment components are laterally just outside of the aligned position, e.g., at −2 and +2 units of separation from the aligned position, as shown by respective peaks  4131   a - b ,  4133   a - b , and  4135   a - b . Similarly to the normal force, the magnitude of the peak strength of shear force depends on the type of magnetic alignment system. In particular, a radially-symmetric closed-loop magnetic alignment system (e.g., magnetic alignment system  4000  of  FIG.  40   ) provides higher magnitude of shear force when just outside of the aligned position than the other types of magnetic alignment systems. This strong shear force can provide tactile feedback to help the user identify when the two components are aligned. In addition, like the strong normal force, the strong shear force can overcome small misalignments due to frictional force and can achieve a more accurate and robust alignment between the primary and secondary alignment components, which in turn can provide a more accurate and robust alignment between a portable electronic device and a wireless charging device within which the magnetic alignment system is implemented. 
     A radially-symmetric closed-loop magnetic alignment system (e.g., magnetic alignment system  4000  of  FIG.  40   ) can provide accurate and robust alignment in the axial and lateral directions. Further, because of the radial symmetry, the alignment system does not have a preferred rotational orientation in the lateral plane about the axis; the shear force profile is the same regardless of relative rotational orientation of the electronic devices being aligned. 
     In some embodiments, a closed-loop magnetic alignment system can be designed to provide one or more preferred rotational orientations.  FIG.  42    shows a simplified top-down view of a secondary alignment component  4218  according to some embodiments. Secondary alignment component  4218  includes sectors  4228   a - h  with radial magnetic orientations as shown by magnetic polarity indicators  4217   a - h . Each of sectors  4228   a - h  can include one or more secondary arcuate magnets (not shown). In this example, secondary magnets in sectors  4228   b ,  4228   d,    4228   f,  and  4228   h  each have a north magnetic pole oriented toward the radially outward side and a south magnetic pole toward the radially inward side, while secondary magnets in sectors  4228   a,    4228   c,    4228   e,  and  4228   g  each have a north magnetic pole oriented toward the radially inward side and a south magnetic pole toward the radially outward side. In other words, magnets in sectors  4228   a - h  of secondary alignment component  4218  have alternating magnetic orientations. A complementary primary alignment component can have sectors with correspondingly alternating magnetic orientations. 
     For example,  FIG.  43 A  shows a perspective view of a magnetic alignment system  4300  according to some embodiments. Magnetic alignment system  4300  includes a secondary alignment component  4318  having alternating radial magnetic orientations (e.g., as shown in  FIG.  42   ) and a complementary primary alignment component  4316 . Some of the arcuate sections of magnetic alignment system  4300  are not shown in order to reveal internal structure; however, it should be understood that magnetic alignment system  4300  can be a complete annular structure. Also shown are components  4302 , which can include, for example, inductive coil assemblies or other components located within the central region of primary annular alignment component  4316  and/or secondary annular alignment component  4318 . Magnetic alignment system  4300  can be a closed-loop magnetic alignment system similar to magnetic alignment system  3800  described above and can include arcuate sectors  4301   b,    4301   c  of alternating magnetic orientations, with each arcuate sector  4301   b,    4301   c  including one or more arcuate magnets in each of primary annular alignment component  4316  and secondary annular alignment component  4318 . In some embodiments, the closed-loop configuration of magnetic alignment system  4300  can reduce or prevent magnetic field leakage that may affect component  4302 . 
       FIG.  43 B  shows an axial cross-section view through one of arcuate sectors  4301   b , and  FIG.  43 C  shows an axial cross-section view through one of arcuate sectors  4301   c.  Arcuate sector  4301   b  includes a primary magnet  4326   b  and a secondary magnet  4328   b.  As shown by orientation indicator  4317   b,  secondary magnet  4328   b  has a magnetic polarity oriented in a radially outward direction, i.e., the north magnetic pole is toward the radially outward side of magnetic alignment system  4300 . Like primary magnets  3826  described above, primary magnet  4326   b  includes an inner arcuate magnetic region  4352   b,  an outer arcuate magnetic region  4354   b , and a central nonmagnetic region  4356   b  (which can include, e.g., an air gap or a region of nonmagnetic material). Inner arcuate magnetic region  4352   b  has a magnetic polarity oriented axially such that the north magnetic pole is toward secondary magnet  4328   b,  as shown by indicator  4353   b,  while outer arcuate magnetic region  4354   b  has an opposite magnetic orientation, with the south magnetic pole oriented toward secondary magnet  4328   b,  as shown by indicator  4355   b.  As described above with reference to  FIG.  38 B , the arrangement of magnetic orientations shown in  FIG.  43 B  results in magnetic attraction between primary magnet  4326   b  and secondary magnet  4328   b.    
     As shown in  FIG.  43 C , arcuate sector  4301   c  has a “reversed” magnetic orientation relative to arcuate sector  4301   b.  Arcuate sector  4301   c  includes a primary magnet  4326   c  and a secondary magnet  4328   c.  As shown by orientation indicator  4317   c,  secondary magnet  4328   c  has a magnetic polarity oriented in a radially inward direction, i.e., the north magnetic pole is toward the radially inward side of magnetic alignment system  4300 . Like primary magnets  3826  described above, primary magnet  4326   c  includes an inner arcuate magnetic region  4352   c,  an outer arcuate magnetic region  4354   c,  and a central nonmagnetic region  4356   c  (which can include, e.g., an air gap or a region of nonmagnetic material). Inner arcuate magnetic region  4352   c  has a magnetic polarity oriented axially such that the south magnetic pole is toward secondary magnet  4328   c,  as shown by indicator  4353   c,  while outer arcuate magnetic region  4354   c  has an opposite magnetic orientation, with the north magnetic pole oriented toward secondary magnet  4328   c,  as shown by indicator  4355   c.  As described above with reference to  FIG.  38 B , the arrangement of magnetic orientations shown in  FIG.  43 C  results in magnetic attraction between primary magnet  4326   c  and secondary magnet  4328   c.    
     An alternating arrangement of magnetic polarities as shown in  FIGS.  42  and  43 A- 8 C  can create a “ratcheting” feel when secondary alignment component  4318  is aligned with primary alignment component  4316  and one of alignment components  4316 ,  4318  is rotated relative to the other about the common axis. For instance, as secondary alignment component  4318  is rotated relative to primary alignment component  4316 , radially-outward magnet  4328   b  alternately come into proximity with a complementary magnet  4326   b  of primary alignment component  4316 , resulting in an attractive magnetic force, and with an anti-complementary magnet  4326   c  of primary alignment component  4316 , resulting in a repulsive magnetic force. If primary magnets  4326   b,    4326   c  and secondary magnets  4328   b,    4328   c  have the same angular size and spacing, in any given orientation, each pair of magnets will experience similar net attractive or repulsive magnetic forces such that alignment is stable and robust in rotational orientations in which complementary magnet pairs  4326   b,    4328   b  and  4326   c,    4328   c  are in proximity. In other rotational orientations, a torque toward a stable rotational orientation can be experienced. 
     In the examples shown in  FIGS.  42  and  43 A- 8 C , each sector includes one magnet, and the direction of magnetic orientation alternates with each magnet. In some embodiments, a sector can include two or more magnets having the same direction of magnetic orientation. For example,  FIG.  44 A  shows a simplified top-down view of a secondary alignment component  4418  according to some embodiments. Secondary alignment component  4418  includes secondary magnets  4428   b  with radially outward magnetic orientations and secondary magnets  4428   c  with radially inward orientations, similarly to secondary alignment component  4318  described above. In this example, the magnets are arranged such that a pair of outwardly-oriented magnets  4428   b  (forming a first sector) are adjacent to a pair of inwardly-oriented magnets  4428   c  (forming a second sector adjacent to the first sector). The pattern of alternating sectors (with two magnets per sector) repeats around the circumference of secondary alignment component  4418 . Similarly,  FIG.  44 B  shows a simplified top-down view of another secondary alignment component  4418 ′ according to some embodiments. Secondary alignment component  4418 ′ includes secondary magnets  4428   b  with radially outward magnetic orientations and secondary magnets  4428   c  with radially inward orientations. In this example, the magnets are arranged such that a group of four radially-outward magnets  4428   b  (forming a first sector) is adjacent to a group of four radially-inward magnets  4428   c  (forming a second sector adjacent to the first sector). The pattern of alternating sectors (with four magnets per sector) repeats around the circumference of secondary alignment component  4418 ′. Although not shown in  FIGS.  44 A and  44 B , the structure of a complementary primary alignment component for secondary alignment component  4418  or  4418 ′ should be apparent in view of  FIGS.  43 A- 8 C . A shear force profile for the alignment components of  FIGS.  44 A and  44 B  can be similar to the ratcheting profile described above, although the number of rotational orientations that provide stable alignment will be different. 
     In other embodiments, a variety of force profiles can be created by changing the alignment of different component magnets of the primary and/or secondary alignment components. As just one example,  FIG.  45    shows a simplified top-down view of a secondary alignment component  4518  according to some embodiments having sectors  4528   a - h  with location-dependent magnetic orientations as shown by magnetic polarity indicators  4517   a - h . In this example, secondary alignment component  4518  can be regarded as bisected by bisector line  4501 , which defines two halves of secondary alignment component  4518 . In a first half  4503 , sectors  4528   e - h  have magnetic polarities oriented radially outward, similarly to examples described above. 
     In the second half  4505 , sectors  4528   a - d  have magnetic polarities oriented substantially parallel to bisector line  4501  rather than radially. In particular, sectors  4528   a  and  4528   b  have magnetic polarities oriented in a first direction parallel to bisector line  4501 , while sectors  4528   c  and  4528   d  have magnetic polarities oriented in the direction opposite to the direction of the magnetic polarities of sectors  4528   a  and  4528   b.  A complementary primary alignment component can have an inner annular region with magnetic north pole oriented toward secondary alignment component  4518 , an outer annular region with magnetic north pole oriented away from secondary alignment component  4518 , and a central non-magnetized region, providing a closed-loop magnetic orientation as described above. The asymmetric arrangement of magnetic orientations in secondary alignment component  4518  can modify the shear force profile such that secondary alignment component  4518  generates less shear force in the direction toward second half  4505  than in the direction toward first half  4503 . In some embodiments, an asymmetrical arrangement of this kind can be used where the primary alignment component is mounted in a docking station and the secondary alignment component is mounted in a portable electronic device that docks with the docking station. Assuming secondary annular alignment component  4518  is oriented in the portable electronic device such that half-annulus  4505  is toward the top of the portable electronic device, the asymmetric shear force can facilitate an action of sliding the portable electronic device downward to dock with the docking station or upward to remove it from the docking station, while still providing an attractive force to draw the portable electronic device into a desired alignment with the docking station. 
     It will be appreciated that the foregoing examples are illustrative and not limiting. Sectors of a primary and/or secondary alignment component can include magnetic elements with the magnetic polarity oriented in any desired direction and in any combination, provided that the primary and secondary alignment components of a given magnetic alignment system have complementary magnetic orientations to provide forces toward the desired position of alignment. Different combinations of magnetic orientations may create different shear force profiles, and the selection of magnetic orientations may be made based on a desired shear force profile. 
     In embodiments described above, it is assumed (though not required) that the magnetic alignment components are fixed in position relative to the device enclosure and do not move in the axial or lateral direction. This provides a fixed magnetic flux. In some embodiments, it may be desirable for one or more of the magnetic alignment components to move in the axial direction. For example, in various embodiments of the present invention, it can be desirable to limit the magnetic flux provided by these magnetic structures. Limiting the magnetic flux can help to prevent the demagnetization of various charge and payment cards that a user might be carrying with an electronic device that incorporates one of these magnetic structures. But in some circumstances, it can be desirable to increase this magnetic flux in order to increase a magnetic attraction between an electronic device and an accessory or a second electronic device. Also, it can be desirable for one or more of the magnetic alignment components to move laterally. For example, an electronic device and an attachment structure or wireless device can be offset from each other in a lateral direction. The ability of a magnetic alignment component to move laterally can compensate for this offset and improve coupling between devices, particularly where a coil moves with the magnetic alignment component. Accordingly, embodiments of the present invention can provide structures where some or all of the magnets in these magnetic structures are able to change positions or otherwise move. Examples of magnetic structures having moving magnets are shown in the following figures. 
       FIGS.  46 A through  46 C  illustrate examples of moving magnets according to an embodiment of the present invention. In these examples, first electronic device  4600  can be a wireless charger, such as any of the wireless chargers shown herein, or other device having a magnet  4610  (which can be, e.g., any of the annular or other magnetic alignment components such as the magnet arrays and alignment magnets described above), while a second electronic device (not shown) can be a phone or other electronic device. In  FIG.  46 A , moving magnet  4610  can be housed in a first electronic device  4600 . First electronic device  4600  can include device enclosure  4630 , magnet  4610 , and shield  4620 . Magnet  4610  can be in a first position (not shown) adjacent to nonmoving shield  4620 . In this position, magnet  4610  can be separated from device enclosure  4630 . As a result, the magnetic flux  4612  at a surface of device enclosure  4630  can be relatively low, thereby protecting magnetic devices and magnetically stored information, such as information stored on payment cards. As magnet  4610  in first electronic device  4600  is attracted to a second magnet (not shown) in the second electronic device, magnet  4610  can move, for example it can move away from shield  4620  to be adjacent to device enclosure  4630 , as shown. With magnet  4610  at this location, magnetic flux  4612  at surface of device enclosure  4630  can be relatively high. This increase in magnetic flux  4612  can help to attract the second electronic device to first electronic device  4600 . 
     With this configuration, it can take a large amount of magnetic attraction for magnet  4610  to separate from shield  4620 . Accordingly, these and other embodiments of the present invention can include a shield that is split into a shield portion and a return plate portion. For example, in  FIG.  46 B , line  4660  can be used to indicate a split of shield  4620  into a shield  4640  and return plate  4650 . 
     In  FIG.  46 C , moving magnet  4610  can be housed in first electronic device  4600 . First electronic device  4600  can include device enclosure  4630 , magnet  4610 , shield  4640 , and return plate  4650 . In the absence of a magnetic attraction, magnet  4610  can be in a first position (not shown) such that shield  4640  can be adjacent to return plate  4650 . Again, in this configuration, magnetic flux  4612  at a surface of device enclosure  4630  can be relatively low. As magnet  4610  and first electronic device  4600  is attracted to a second magnet (not shown) in a second electronic device (not shown), magnet  4610  can move, for example it can move away from return plate  4650  to be adjacent to device enclosure  4630 , as shown. In this configuration, shield  4640  can separate from return plate  4650  and the magnetic flux  4612  at a surface of device enclosure  4630  can be increased. As before, this increase in magnetic flux  4612  can help to attract the second electronic device to the first electronic device  4600 . 
     In these and other embodiments of the present invention, various housings and structures can be used to guide a moving magnet. Also, various surfaces can be used in conjunction with these moving magnets. These surfaces can be rigid. Alternatively, these surfaces can be compliant and at least somewhat flexible. Examples are shown in the following figures. 
       FIGS.  47 A and  47 B  illustrate a moving magnetic structure according to an embodiment of the present invention. In this example, first electronic device  4700  can be a wireless charger, such as any of the wireless chargers shown herein, or other device having a magnet  4710  (which can be, e.g., any of the annular or other magnetic alignment components such as the magnet arrays and alignment magnets described above), while a second electronic device  4760  (shown in  FIG.  47 B ) can be a phone or other electronic device.  FIG.  47 A  illustrates a moving first magnet  4710  in a first electronic device  4700 . First electronic device  4700  can include first magnet  4710 , protective surface  4712 , housings  4720  and  4722 , compliant structure  4724 , shield  4740 , and return plate  4750 . In this figure, first magnet  4710  is not attracted to a second magnet (not shown), and therefore shield  4740  is magnetically attracted to or attached to return plate  4750 . In this position, compliant structure  4724  can be expanded or relaxed. Compliant structure  4724  can be formed of an elastomer, silicon rubber open cell foam, silicon rubber, polyurethane foam, or other foam or other compressible material. 
     In  FIG.  47 B , second electronic device  4760  has been brought into proximity of first electronic device  4700 . Second magnet  4770  can attract first magnet  4710 , thereby causing shield  4740  and return plate  4750  to separate from each other. Housings  4720  and  4722  can compress compliant structure  4724 , thereby allowing protective surface  4712  of first electronic device  4700  to move towards or adjacent to housing  4780  of second electronic device  4760 . Second magnet  4770  can be held in place in second electronic device  4760  by housing  4790  or other structure. As second electronic device  4760  is removed from first electronic device  4700 , first magnet  4710  and shield  4740  can be magnetically attracted to return plate  4750 , as shown in  FIG.  47 A . 
       FIGS.  48 A and  48 B  illustrate moving magnetic structures according to an embodiment of the present invention. In this example, first electronic device  4800  can be a wireless charger, such as any of the wireless chargers shown herein, or other device having a magnet  4810  (which can be, e.g., any of the annular or other magnetic alignment components such as the magnet arrays and alignment magnets described above), while second electronic device  4860  (shown in  FIG.  48 B ) can be a phone or another electronic device.  FIG.  48 A  illustrates a moving first magnet  4810  in a first electronic device  4800 . First electronic device  4800  can include first magnet  4810 , pliable surface  4812 , housing portions  4820  and  4822 , shield  4840 , and return plate  4850 . In this figure, first magnet  4810  is not attracted to a second magnet, and therefore shield  4840  is magnetically attached or attracted to return plate  4850 . In this position, pliable surface  4812  can be relaxed. Pliable surface  4812  can be formed of an elastomer, silicon rubber open cell foam, silicon rubber, polyurethane foam, or other foam or other compressible material. 
     In  FIG.  48 B , second electronic device  4860  has been brought into the proximity of first electronic device  4800 . Second magnet  4870  can attract first magnet  4810 , thereby causing shield  4840  and return plate  4850  to separate from each other. First magnet  4810  can stretch pliable surface  4812  towards second electronic device  4860 , thereby allowing first magnet  4810  of first electronic device  4800  to move towards housing  4880  of second electronic device  4860 . Second magnet  4870  can be held in place in second electronic device  4860  by housing  4880  or other structure. As second electronic device  4860  is removed from first electronic device  4800 , first magnet  4810  and shield  4840  can be magnetically attracted to return plate  4850  as shown in  FIG.  48 A . 
       FIGS.  49    through  FIG.  51    illustrate a moving magnetic structure according to an embodiment of the present invention. In this example, first electronic device  4900  can be a wireless charger, such as any of the wireless chargers shown herein, or other device having a magnet  4910  (which can be, e.g., any of the annular or other magnetic alignment components such as the magnet arrays and alignment magnets described above), while second electronic device  4890  (shown in  FIG.  50   ) can be a phone or other electronic device. In  FIG.  49   , first magnet  4910  and shield  4940  can be magnetically attracted or attached to return plate  4950  in first electronic device  4900 . First electronic device  4900  can be at least partially housed in device enclosure  4920 . In  FIG.  50   , housing  4980  of second electronic device  4960  can move laterally across a surface of device enclosure  4920  of first electronic device  4900  in a direction  4985 . Second magnet  4970  in second electronic device  4960  can begin to attract first magnet  4910  in first electronic device  4900 . This magnetic attraction  4915  can cause first magnet  4910  and shield  4940  to pull away from return plate  4950  by overcoming the magnetic attraction  4945  between shield  4940  and return plate  4950 . In  FIG.  51   , second magnet  4970  in second electronic device  4960  has become aligned with first magnet  4910  in first electronic device  4900 . First magnet  4910  and shield  4940  have pulled away from return plate  4950  thereby reducing the magnetic attraction  4945 . First magnet  4910  has moved nearby or adjacent to device enclosure  4920 , thereby increasing the magnetic attraction  4915  to second magnet  4970  in second electronic device  4960 . 
     As shown in  FIG.  49    through  FIG.  51   , the magnetic attraction between first magnet  4910  in first electronic device  4900  and the second magnet  4970  in the second electronic device  4960  can increase when first magnet  4910  and shield  4940  pull away from return plate  4950 . This is shown graphically in the following figures. 
       FIG.  52    illustrates a normal force between a first magnet in first electronic device and a second magnet in a second electronic device as a function of a lateral offset between them. As shown in  FIG.  49    through  FIG.  51   , with a large offset between first magnet  4910  and second magnet  4970 , first magnet  4910  and shield  4940  can remain attached to return plate  4950  in first electronic device  4900  and the magnetic attraction  4915  can be minimal. The shear force necessary to overcome this magnetic attraction is illustrated here as curve  5210 . As shown in  FIG.  50   , as the offset or lateral distance between first magnet  4910  and second magnet  4970  decreases, first magnet  4910  and shield  4940  can pull away or separate from return plate  4950 , thereby increasing the magnetic attraction  4915  between first magnet  4910  and second magnet  4970 . This is illustrated here as discontinuity  5220 . As shown in  FIG.  51   , as first magnet  4910  and second magnet  4970  come into alignment, the magnetic attraction  4915  increases along curve  5230  to a maximum  5240 . The difference between curve  5210  and curve  5230  can show the increase in magnetic attraction between a phone or other electronic device, such as second electronic device  4960  and a wireless charger, such as first electronic device  4900 , that results from first magnet  4910  being able to move axially. It should also be noted that in this example first magnet  4910  does not move in a lateral direction, though in other embodiments of the present invention, it is capable of such movement. Where first magnet  4910  is capable of moving in a lateral direction, curve  5230  can have a flattened peak from an offset of zero to an offset that can be overcome by a range of possible lateral movement of first magnet  4910 . 
       FIG.  53    illustrates a shear force between a first magnet in a first electronic device and a second magnet in a second electronic device as a function of a lateral offset between them. With no offset between first magnet  4910  and second magnet  4970 , there it is no shear force to move second magnet  4970  relative to first magnet  4910 , as shown in  FIG.  51   . As the offset is increased, the shear force, that is the force attempting to realign the magnets, can increase along curve  5340 . At discontinuity  5310 , first magnet  4910  and shield  4940  can return to return plate  4950  (as shown in  FIG.  49    and  FIG.  50   ), thereby decreasing the magnetic shear force to point  5320 . The magnetic shear force can continue to drop off along curve  5330  as the offset increases. The difference between curve  5330  and curve  5340  can show the increase in magnetic attraction between a phone or other electronic device, such as second electronic device  4960  and wireless charger, such as first electronic device  4900 , that results from first magnet  4910  being able to move axially. It should also be noted that in this example first magnet  4910  does not move in a lateral direction, though in other examples it is capable of such movement. Where first magnet  4910  is capable of moving in a lateral direction, curve  5330  can remain at zero until the lateral movement of the second magnet  4970  overcomes the range of possible lateral movement of first magnet  4910 . 
     For various applications, it may be desirable to enable a device having a magnetic alignment component to identify other devices that are brought into alignment. In some embodiments where the devices support a wireless charging standard that defines a communication protocol between devices, the devices can use that protocol to communicate. For example, the Qi standard for wireless power transfer defines a communication protocol that enables a power-receiving device (i.e., a device that has an inductive coil to receive power transferred wirelessly) to communicate information to a power-transmitting device (i.e., a device that has an inductive coil to generate time-varying magnetic fields to transfer power wirelessly to another device) via a modulation scheme in the inductive coils. The Qi communication protocol or similar protocols can be used to communicate information such as device identification or charging status or requests to increase or decrease power transfer from the power-receiving device to the power-transmitting device. 
     In some embodiments, a separate communication subsystem, such as an NFC subsystem can be provided to enable additional communication between devices. For example, each device that has an annular magnetic alignment component can also have an NFC coil that can be disposed inside and concentric with the annular magnetic alignment component. Where the device also has an inductive charging coil (which can be a transmitter coil or a receiver coil), the NFC coil can be disposed in a gap between the inductive charging coil and an annular magnetic alignment component. In some embodiments, the NFC coils can be used to allow a portable electronic device to identify other devices, such as a wireless charging device and/or an auxiliary device, when the respective magnetic alignment components of the devices are brought into alignment. For example, the NFC coil of a power-receiving device can be coupled to an NFC reader circuit while the NFC coil of a power-transmitting device or an accessory device is coupled to an NFC tag circuit. When devices are brought into proximity, the NFC reader circuit of the power-receiving device can be activated to read the NFC tag of the power-transmitting device and/or the accessory device. In this manner, the power-receiving device can obtain information (e.g., device identification) from the power-transmitting device and/or the accessory device. 
     In some embodiments, an NFC reader in a portable electronic device can be triggered by detecting a change in the DC (or static) magnetic field generated by the magnetic alignment component of the portable electronic device that corresponds to a change expected when another device with a complementary magnetic alignment component is brought into alignment. When the expected change is detected, the NFC reader can be activated to read an NFC tag in the other device, assuming the other device is present. 
     In some embodiments, an NFC tag may be located in a device that includes a wireless charger and an annular alignment structure. The NFC tag can be positioned and configured such that when the wireless charger device is aligned with a portable device having a complementary annular alignment structure and an NFC reader, the NFC tag is readable by the NFC reader of the portable electronic device. 
       FIG.  54    shows an exploded view of a wireless charger device  5402  incorporating an NFC tag according to some embodiments, and  FIG.  55    shows a partial cross-section view of wireless charger device  5402  according to some embodiments. As shown in  FIG.  54   , wireless charger device  5402  can include an enclosure  5404 , which can be made of plastic or metal (e.g., aluminum), and a charging surface  5406 , which can be made of silicone, plastic, glass, or other material that is permeable to AC and DC magnetic fields. Charging surface  5406  can be shaped to fit within a circular opening  5403  at the top of enclosure  5404 . 
     A wireless transmitter coil assembly  5411  can be disposed within enclosure  5404 . Wireless transmitter coil assembly  5411  can include a wireless transmitter coil  5412  for inductive power transfer to another device as well as AC magnetic and/or electric shield(s)  5413  disposed around some or all surfaces of wireless transmitter coil  5412 . Control circuitry  5414  (which can include, e.g., a logic board and/or power circuitry) to control wireless transmitter coil  5412  can be disposed in the center of coil  5412  and/or underneath coil  5412 . In some embodiments, control circuitry  5414  can operate wireless transmitter coil  5412  in accordance with a wireless charging protocol such as the Qi protocol or other protocols. 
     A primary annular magnetic alignment component  5416  can surround wireless transmitter coil assembly  5411 . Primary annular magnetic alignment component  5416  can include a number of arcuate magnet sections arranged in an annular configuration as shown. Each arcuate magnet section can include an inner arcuate region having a magnetic polarity oriented in a first axial direction, an outer arcuate region having a magnetic polarity oriented in a second axial direction opposite the first axial direction, and a central arcuate region that is not magnetically polarized. In some embodiments, the diameter and thickness of primary annular magnetic alignment component  5416  is chosen such that arcuate magnet sections of primary annular magnetic alignment component  5416  fit under a lip  5409  at the top surface of enclosure  5404 , as best seen in  FIG.  55   . For instance, each arcuate magnet section can be inserted into position under lip  5409 , either before or after magnetizing the inner and outer regions. In some embodiments, primary annular magnetic alignment component  5416  can have a gap  5436  between two adjacent arcuate magnet sections. Gap  5436  can be aligned with an opening  5407  in a side surface of enclosure  5404  to allow external wires to be connected to wireless transmitter coil  5412  and/or control circuitry  5414 . 
     A support ring subassembly  5440  can include an annular frame  5442  that extends in the axial direction and a friction pad  5444  at the top edge of frame  5442 . Friction pad  5444  can be made of a material such as silicone or thermoplastic elastomers (TPE) such as thermoplastic urethane (TPU) and can provide support and protection for charging surface  5406 . Frame  5442  can be made of a material such as polycarbonate (PC), glass-fiber reinforced polycarbonate (GFPC), or glass-fiber reinforced polyamide (GFPA). Frame  5442  can have an NFC coil  5464  disposed thereon. For example, NFC coil  5464  can be a four-turn or five-turn solenoidal coil made of copper wire or other conductive wire that is wound onto frame  5442 . In some embodiments, NFC coil  5464  can be electrically connected to NFC tag circuitry (not shown) that can be disposed on frame  5442 . The relevant design principles of NFC circuits are well understood in the art and a detailed description is omitted. Frame  5442  can be inserted into a gap region  5417  between primary annular magnetic alignment component  5416  and wireless transmitter coil assembly  5411 . In some embodiments, gap region  5417  is shielded by AC shield  5413  from AC electromagnetic fields generated in wireless transmitter coil  5412  and is also shielded from DC magnetic fields of primary annular magnetic alignment component  5416  by the closed-loop configuration of the arcuate magnet sections. 
       FIG.  56    shows a flow diagram of a process  5600  that can be implemented in portable electronic device  5004  according to some embodiments. In some embodiments, process  5600  can be performed iteratively while portable electronic device  5004  is powered on. At block  5602 , process  5600  can determine a baseline magnetic field, e.g., using magnetometer  5080 . At block  5604 , process  5600  can continue to monitor signals from magnetometer  5080  until a change in magnetic field is detected. At block  5606 , process  5600  can determine whether the change in magnetic field matches a magnitude and direction of change associated with alignment of a complementary magnetic alignment component. If not, then the baseline magnetic field can be updated at block  5602 . If, at block  5606 , the change in magnetic field matches a magnitude and direction of change associated with alignment of a complementary alignment component, then at block  5608 , process  5600  can activate the NFC reader circuitry associated with NFC coil  5060  to read an NFC tag of an aligned device. At block  5610 , process  5600  can receive identification information read from the NFC tag. At block  5612 , process  5600  can modify a behavior of portable electronic device  5004  based on the identification information, for example, generating a color wash effect as described above. After block  5612 , process  5600  can optionally return to block  5602  to provide continuous monitoring of magnetometer  5080 . It should be understood that process  5600  is illustrative and that other processes may be performed in addition to or instead of process  5600 . 
     It is well understood that the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled so as to minimize risks of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users. 
     The above description of embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form described, and many modifications and variations are possible in light of the teaching above. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Thus, it will be appreciated that the invention is intended to cover all modifications and equivalents within the scope of the following claims.

Metadata:
Filing Date: 20210910
Publication Date: 20240903
Grant Date: 20240903
Priority Date: 20200923
Inventors: HAUG, Grant S.
GRAHAM, Christopher S.
THOMPSON, PAUL J.
Assignee: APPLE INC
CPC Classifications: [{"code": "H02J50/90", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/0044", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/70", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/00034", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02J50/70", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/0042", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/005", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J7/0044", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J7/0044", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J50/90", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/70", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/0044", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/005", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 80740966