PATENT DOCUMENT

Publication Number: US-11839279-B2
Application Number: US-202117223690-A
Country: US
Kind Code: B2

Title: Magnetically attachable wallet

Abstract:
Accessories that can add new functionality to an electronic device. These accessories can provide additional functionality that allow for the replacement of a physical object that would otherwise be carried in addition to and separate from the electronic device. These accessories can further provide improvements, such as a reduction in size or improvement in functionality over the physical object to be replaced.

Claims:
What is claimed is: 
     
       1. An attachable wallet comprising:
 a back panel, wherein the back panel has a passage from an outside surface of the back panel to an interior compartment; 
 a front panel, wherein the back panel and the front panel are attached along two sides and a bottom of the attachable wallet thereby forming a throat at a top of the attachable wallet, the throat providing access to the interior compartment; and 
 a subassembly in the back panel, the subassembly comprising:
 a metallic shunt; and 
 a magnet array between the outside surface of the back panel and the metallic shunt, wherein magnets in the magnet array laterally and circumferentially surround the passage through the back panel. 
 
 
     
     
       2. The attachable wallet of  claim 1  wherein the magnet array attaches the attachable wallet to a surface of an electronic device. 
     
     
       3. The attachable wallet of  claim 2  further comprising an alignment magnet to align the attachable wallet in a specific orientation relative to the surface of the electronic device. 
     
     
       4. The attachable wallet of  claim 3  wherein the metallic shunt comprises a spring tab biased towards the interior compartment. 
     
     
       5. The attachable wallet of  claim 4  wherein the back panel further comprises a ferrite and a near-field communication circuit, wherein the ferrite is attached to the metallic shunt and the ferrite is between the near-field communication circuit and the metallic shunt. 
     
     
       6. The attachable wallet of  claim 5  wherein the front panel comprises a shield layer, where the shield layer includes a ferrite layer and a metal layer. 
     
     
       7. An attachable wallet comprising:
 a back panel having a passage from an outside surface of the back panel to an interior compartment; 
 a front panel, wherein the back panel and the front panel are attached along two sides and a bottom of the attachable wallet thereby forming a throat at a top of the attachable wallet, the throat providing access to the interior compartment; and 
 a subassembly in the back panel, the subassembly comprising:
 a metallic shunt comprising a spring tab extending from the metallic shunt towards the interior compartment; 
 a magnet array between the outside surface of the back panel and the metallic shunt, wherein the magnet array attaches the attachable wallet to a surface of an electronic device, wherein magnets in the magnet array laterally and circumferentially surround the passage through the back panel; and 
 an alignment magnet between the outside surface of the back panel and the metallic shunt, the alignment magnet to align the attachable wallet to the surface of the electronic device. 
 
 
     
     
       8. The attachable wallet of  claim 7  wherein the metallic shunt is formed of stainless steel and the spring tab is stamped from the metallic shunt and biased towards the interior compartment. 
     
     
       9. The attachable wallet of  claim 8  wherein the back panel further comprises a ferrite and a near-field communication circuit, wherein the ferrite is attached to the metallic shunt and the ferrite is between the near-field communication circuit and the metallic shunt. 
     
     
       10. The attachable wallet of  claim 9  wherein the ferrite is formed of a plurality of layers of ferritic material. 
     
     
       11. An attachable wallet comprising:
 a front panel comprising a shield layer, the shield layer comprising:
 a ferritic layer; 
 a first adhesive layer; and 
 a metal layer attached to the ferritic layer by the first adhesive layer; and 
 
 a back panel, wherein the back panel and the front panel are stitched together along two sides and a bottom of the attachable wallet thereby forming a throat at a top of the attachable wallet, the throat providing access to an interior compartment, the back panel comprising:
 a metallic shunt supporting a spring tab, the spring tab extending from the metallic shunt towards the interior compartment; and 
 an attachment feature arranged to attach the attachable wallet to a surface. 
 
 
     
     
       12. The attachable wallet of  claim 11  further comprising:
 an alignment feature to align the attachable wallet to the surface. 
 
     
     
       13. The attachable wallet of  claim 12  wherein the attachment feature comprises a magnet array. 
     
     
       14. The attachable wallet of  claim 13  wherein the alignment feature is a magnet. 
     
     
       15. The attachable wallet of  claim 14  wherein the back panel has a passage from an outside of the back panel to the interior compartment. 
     
     
       16. The attachable wallet of  claim 15  wherein the magnet array is attached to the metallic shunt and laterally and circumferentially surrounds the passage through the back panel. 
     
     
       17. The attachable wallet of  claim 11  wherein the shield layer further comprises a protective layer over the ferritic layer. 
     
     
       18. The attachable wallet of  claim 17  wherein the protective layer is formed of a polyester. 
     
     
       19. The attachable wallet of  claim 17  further comprising a liner and a second adhesive layer to attach the metal layer to the liner. 
     
     
       20. The attachable wallet of  claim 19  wherein the liner is formed of taffeta.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     The present application claims the benefit of and priority to U.S. provisional application No. 63/081,833, filed Sep. 22, 2020, which is hereby incorporated by reference. 
    
    
     BACKGROUND 
     The number of types of electronic devices that are commercially available has increased tremendously the past few years and the rate of introduction of new devices shows no signs of abating. Devices such as tablet computers, laptop computers, desktop computers, all-in-one computers, cell phones, storage devices, wearable-computing devices, portable media players, navigation systems, monitors, adapters, and others, have become ubiquitous. 
     As a result of the ubiquity and increasing functionality of these electronic devices, they now travel with us wherever we go. They are often used during or in conjunction with many daily activities, either while performing an activity or in a manner that supplements an activity. 
     As a result of this constant companionship, it can be desirable for these electronic devices to assume other functions. For example, it can be desirable if the additional functionality can replace a physical object that would otherwise be carried in addition to and separate from the electronic device. That is, it can be desirable to provide an accessory that can replace the physical object. 
     These electronic devices and physical objects are often carried in a pocket, purse, backpack, satchel, or other such pouch. As such, the size of these electronic devices and physical objects is always of concern. Accordingly, it can be desirable that an accessory that is to replace the physical object have a small and efficient form factor. It can also be desirable that the accessory provide other improvements over the physical object that is being replaced. 
     Thus, what is needed are accessories that can add new functionality to an electronic device. It can also be desirable if the additional functionality is able to allow for the replacement of a physical object that would otherwise be carried in addition to and separate from the electronic device. It can also be desirable for such an accessory to provide other improvements, such as a reduction in size or improvement in functionality over the physical object that is being replaced. 
     SUMMARY 
     Accordingly, embodiments of the present invention can provide accessories that can add new functionality to an electronic device. These accessories can provide additional functionality that allow for the replacement of a physical object that would otherwise be carried in addition to and separate from the electronic device. These accessories can further provide other improvements, such as a reduction in size or improvement in functionality, over the physical object. 
     These and other embodiments of the present invention can provide an accessory that can add the functionality of a wallet to an electronic device. In providing this additional functionality, a need for a conventional physical wallet can be negated, that is, a conventional wallet can be replaced by the accessory, which can be an attachable wallet. This replacement can reduce a number of separate items that might otherwise be carried. This accessory can provide other improvements over a conventional wallet by having a small and efficient form factor. The accessory can provide further improvements such as providing effective retention features for securing items in the accessory and effective extraction features for removing items from the accessory. In this way, the function of a physical wallet can be added to an electronic device thereby negating the necessity of carrying a separate physical wallet. Further, the function of the wallet itself can be improved by adding these retention, extraction, and other features. 
     These and other embodiments of the present invention can provide an accessory that can add the functionality of a wallet to an electronic device by including an attachment feature that can attach the accessory to a surface of an electronic device. The attachment feature can include a magnet. The attachment feature can include multiple magnets. The attachment feature can include a magnet array. The magnet array can be arranged in a circular pattern. The magnet array can be magnetically attracted to a corresponding magnetic array in the electronic device. 
     These and other embodiments of the present invention can further include an alignment feature for the accessory, where the alignment feature can align the accessory in a particular orientation relative to the electronic device. The alignment feature can include magnets in the magnet array. The alignment feature can also or instead be one or more additional magnets that are separate and spaced apart from the magnet array. 
     These and other embodiments of the present invention can provide an accessory having a small and efficient form factor. The accessory can include a front panel and a back panel. The front panel can be attached to the back panel along sides and a bottom of the front panel and the back panel. The top of the front panel and the top of the back panel can be left unattached to each other to form a throat, where the throat can provide access to an interior compartment. In this way the entirety of the accessory can provide an interior compartment that can be used to hold items. 
     These and other embodiments of the present invention can provide further improvements such as an improvement in functionality. An accessory can include a retention feature for securing items in the accessory. This retention feature can include a spring tab that can be attached to or formed as part of a metallic shunt in the back panel. The spring tab can be biased towards an interior compartment to secure items in the interior compartment in place. An accessory can include an extraction feature for removing items from the accessory. A passage can extend through the back panel from a back outside surface of the back panel to the interior compartment. This passage can be used to apply a force to an item in the interior compartment in a direction that can move an item in the interior compartment to the throat of the accessory where it can be removed from the accessory. 
     These and other embodiments of the present invention can provide an accessory that can provide magnetic shielding for items in the interior compartment, as well as for items around and on a backside of the accessory. The back panel can include a metallic shunt supporting a magnet array and an alignment magnet. The metallic shunt can be positioned between the interior compartment and the magnet array and between the interior compartment and the alignment magnet such that items in the interior compartment can be protected from magnetic flux from the magnet array and the alignment magnet. That is, the metallic shunt can direct the magnetic field of the magnet array and alignment magnet away from items in the interior compartment and towards an electronic device attached at the back panel. This can help to protect magnetically stored information on credit cards, transit cards, and the like from inadvertent erasure. This can also help to increase the magnetic attraction between the magnet array and alignment magnet and corresponding magnets in the electronic device. 
     These and other embodiments of the present invention can further reduce unwanted magnetic fields. The passage through the back panel of the accessory can be laterally and circumferentially surrounded by the magnet array. A ferritic piece or ferrite can be located laterally and circumferentially around the passage and the ferritic piece can be laterally and circumferentially surrounded by the magnet array. In this configuration the ferritic piece can provide further magnetic shielding for items in the interior compartment from the magnet array and alignment magnet. Near-field communication (NFC) circuitry can further be included in the back panel. This NFC circuitry can be located on or near an NFC inlay and can be located between the ferrite and a backside of the attachable wallet. In this configuration, the ferrite can help to prevent the NFC circuitry from being detuned by the metallic shunt and by metallic cards or other objects in the interior compartment. 
     These and other embodiments of the present invention can provide an accessory that can be identified by an electronic device, for example by reading a tag or other information on an electronic circuit of the NFC circuitry. Once an electronic device identifies that it is attached to an accessory, such as an attachable wallet, the electronic device can commence various operations. For example, the electronic device can comprise a magnetometer. The magnetometer can detect the magnet array in the attachable wallet. In response to this detection, the electronic device can generate a field using near-field communication circuitry. The near-field communication circuitry in the electronic device can detect near-field communication circuitry in the attachable wallet and determine that it is attached to the attachable wallet. The near-field communication circuitry in the attachable wallet can include the tag or other electronic circuit, capacitors, and other components. The tag can include identifying information. This circuitry can also be used to detect a removal of an accessory such as an attachable wallet from the electronic device. In response to detecting a disconnection, the electronic device can remember the location of where the attachable wallet is detached, along with other information. The identification of the attachable wallet can be used by the electronic device in other ways. For example, following attachment, graphics including a color of the attachable wallet can be displayed on a screen of the electronic device. Other personalized information, such as the name of the owner of the attachable wallet, can also be shown. The electronic device can further adjust one or more of its constituent components, such as antennas, cameras, or others. 
     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 an attachable wallet according to an embodiment of the present invention; 
         FIG.  2    illustrates an improved retention feature according to an embodiment of the present invention; 
         FIG.  3 A  and  FIG.  3 B  illustrate a subassembly for use in an attachable wallet according to an embodiment of the present invention,  FIG.  3 C  illustrates another view of the subassembly of  FIG.  3 B , and  FIG.  3 D  is a more detailed view the subassembly of  FIG.  3 B ; 
         FIG.  4    illustrates layers that can be utilized to form a front panel for an attachable wallet according to an embodiment of the present invention; 
         FIG.  5    illustrates layers that can be utilized to form a portion of a back panel for an attachable wallet according to an embodiment of the present invention; 
         FIG.  6    and  FIG.  7    illustrate layers that can be utilized to form a portion of a back panel for an attachable wallet according to an embodiment of the present invention; 
         FIG.  8    shows a simplified representation of a wireless charging system incorporating a magnetic alignment system according to some embodiments; 
         FIG.  9 A  shows a perspective view of a magnetic alignment system according to some embodiments, and  FIG.  9 B  shows a cross-section through the magnetic alignment system of  FIG.  9 A ; 
         FIG.  10 A  shows a perspective view of a magnetic alignment system according to some embodiments, and  FIG.  10 B  shows a cross-section through the magnetic alignment system of  FIG.  10 A ; 
         FIG.  11    shows a simplified top-down view of a secondary alignment component according to some embodiments; 
         FIG.  12 A  shows a perspective view of a magnetic alignment system according to some embodiments, and  FIG.  12 B  shows an axial cross-section view through a portion of the system of  FIG.  12 A , while  FIGS.  12 C through  12 E  show examples of arcuate magnets with radial magnetic orientation according to some embodiments; 
         FIGS.  13 A and  13 B  show graphs of force profiles for different magnetic alignment systems, according to some embodiments; 
         FIG.  14    shows a simplified top-down view of a secondary alignment component according to some embodiments; 
         FIG.  15 A  shows a perspective view of a magnetic alignment system according to some embodiments, and  FIGS.  15 B and  15 C  show axial cross-section views through different portions of the system of  FIG.  15 A ; 
         FIGS.  16 A and  16 B  show simplified top-down views of secondary alignment components according to various embodiments; 
         FIG.  17    shows a simplified top-down view of a secondary alignment component according to some embodiments; 
         FIG.  18    shows an example of a magnetic alignment system with an annular alignment component and a rotational alignment component according to some embodiments; 
         FIGS.  19 A and  19 B  show an example of rotational alignment according to some embodiments; 
         FIGS.  20 A and  20 B  show a perspective view and a top view of a rotational alignment component having a “z-pole” configuration according to some embodiments; 
         FIGS.  21 A and  21 B  show a perspective view and a top view of a rotational alignment component having a “quad pole” configuration according to some embodiments; 
         FIGS.  22 A and  22 B  show a perspective view and a top view of a rotational alignment component having an “annulus design” configuration according to some embodiments; 
         FIGS.  23 A and  23 B  show a perspective view and a top view of a rotational alignment component having a “triple pole” configuration according to some embodiments; 
         FIG.  24    shows graphs of torque as a function of angular rotation for magnetic alignment systems having rotational alignment components according to various embodiments; 
         FIG.  25    shows a portable electronic device having an alignment system with multiple rotational alignment components according to some embodiments; 
         FIGS.  26 A through  26 C  illustrate moving magnets according to an embodiment of the present invention; 
         FIGS.  27 A and  27 B  illustrate a moving magnetic structure according to an embodiment of the present invention; 
         FIGS.  28 A and  28 B  illustrate a moving magnetic structure according to an embodiment of the present invention; 
         FIG.  29    through  FIG.  31    illustrate a moving magnetic structure according to an embodiment of the present invention; 
         FIG.  32    illustrates a normal force between a first magnet in a first electronic device and a second magnet in a second electronic device; 
         FIG.  33    illustrates a shear force between a first magnet in a first electronic device and a second magnet in a second electronic device; 
         FIG.  34    shows an exploded view of a wireless charger device incorporating an NFC tag circuit according to some embodiments; 
         FIG.  35    shows a partial cross-section view of a wireless charger device according to some embodiments; 
         FIG.  36    illustrates a portion of NFC inlay according to an embodiment of the present invention; 
         FIG.  37 A  and  FIG.  37 B  illustrate portions of an NFC inlay according to an embodiment of the present invention; 
         FIG.  38    illustrates a cross-section of a ferrite according to an embodiment of the present invention; 
         FIG.  39    illustrates a cross-section of a shield layer according to an embodiment of the present invention; and 
         FIG.  40    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 an attachable wallet according to an embodiment of the present invention. This figure, as with the other included figures, is shown for illustrative purposes and does not limit other the possible embodiments of the present invention or the claims. 
     In this example, an accessory, specifically attachable wallet  100 , can be attached to a back surface  202  of electronic device  200 . This can leave a screen (not shown) or other component on front surface  204  of electronic device  200  unobstructed. Electronic device  200  can be a phone or other electronic device. Attachable wallet  100  can include an attachment feature for attaching attachable wallet  100  to back surface  202  of electronic device  200 . Attachable wallet  100  can further include an alignment feature for aligning attachable wallet  100  to back surface  202  of electronic device  200  in a specific orientation. In this way, the functionality of a physical wallet can be added to electronic device  200 . This can eliminate the need for a conventional wallet that would otherwise be carried separately and in addition to electronic device  200 . 
     Attachable wallet  100  can provide further additional advantages and improvements. For example, attachable wallet  100  can provide a reduction in size over a conventional wallet. In this example, attachable wallet can include front panel  110  and back panel  120 . Front panel  110  can be attached to back panel  120  along sides  112  of front panel  110  and sides  122  of back panel  120 . Bottom  114  of front panel  110  can be attached to bottom  124  of back panel  120 . A top  116  of front panel  110  and top  126  of back panel  120  can be left unattached to each other to form throat  140 . Throat  140  can provide access to an interior compartment  150 . Interior compartment  150  can be used to hold cards, money, or other objects, referred to collectively as card or cards  300 . This configuration can provide a small and efficient form factor for attachable wallet  100 . 
     Attachable wallet  100  can further provide improvements in functionality, including an improved retention feature (shown in  FIG.  2   ) and an improved extraction feature (shown in  FIGS.  5 - 7   .) Attachable wallet  100  can provide other features, such as a near-field communication circuit (shown in  FIGS.  3 C and  3 D ), which can be used by electronic device  200  to identify attachable wallet  100 . This identification can be an identification of the attached accessory as an attachable wallet  100 . The identification can be the identification of a specific attachable wallet  100 . 
       FIG.  2    illustrates an improved retention feature according to an embodiment of the present invention. Back panel  120  can support inner shunt  160  (shown in  FIG.  3 B ) having spring tab  162 . As card  300  is inserted into interior compartment  150  (shown in  FIG.  1   ), it can engage spring tab  162 . Spring tab  162  can apply a pressure against card  300  holding it in place against front panel  110 . This arrangement can help to retain card  300  in place in attachable wallet  100  (shown in  FIG.  1   .) 
     Again, attachable wallet  100  can include an attachment feature for attaching to electronic device  200  (shown in  FIG.  1   .) Attachable wallet  100  can further include an alignment feature for aligning attachable wallet  100  to electronic device  200  in a specific orientation. The attachment feature and the alignment feature can be magnets. These magnets can pose a risk of accidental erasure for information stored on magnetic stripe  310  of card  300 , where card  300  can be a credit card, transit pass, or other card having magnetically stored information. Accordingly, one or more metallic shunts can be used to provide shielding for card  300 . Examples are shown in the following figures. 
       FIG.  3 A  and  FIG.  3 B  illustrate a subassembly for use in an attachable wallet according to an embodiment of the present invention. In this example, attachable wallet  100  (shown in  FIG.  1   ) can include magnet array  190  as an attachment feature to attach attachable wallet  100  to electronic device  200  (shown in  FIG.  1   .) Magnet array  190  is shown in further detail below starting in  FIG.  8   . Magnet array  190  can be attached to outer shunt  180  using adhesive layer  172 , or magnet array  190  can move relative to outer shunt  180  as shown below in  FIG.  26    through  FIG.  33   . Outer shunt  180  can be attached to inner shunt  160  using adhesive layer  176 . 
     Also in this example, attachable wallet  100  can include alignment magnet  192  as an alignment feature to align attachable wallet  100  to electronic device  200  in a specific orientation. Alignment magnet  192  is shown in further detail below starting in  FIG.  18   . Alignment magnet  192  can attached to outer shunt  180  using adhesive layer  174 . 
     With this arrangement, inner shunt  160  and outer shunt  180  can be between magnet array  190  and card  300  and also between alignment magnet  192  and card  300  when card  300  is stored in interior compartment  150  (shown in  FIG.  1   .) Accordingly, inner shunt  160  and outer shunt  180  can provide shielding to protect information stored on magnetic stripe  310  of card  300  from accidental erasure. 
     Again, spring tab  162  can provide a retention feature to hold card  300  in place in interior compartment  150  of attachable wallet  100 . Spring tab  162  can be stamped from inner shunt  160  leaving opening  163 . To improve shielding and to provide an attachment location for alignment magnet  192 , outer shunt  180  can include wide portion  186 . Wide portion  186  can cover opening  163  in inner shunt  160 . The subassembly can further include opening  170 . Opening  170  can extend from interior compartment  150  to an outside surface of back panel  120 . That is, opening  170  can extend from interior compartment  150  to the back surface of attachable wallet  100  where attachable wallet attaches to electronic device  200 . Opening  170  can provide an improved extraction feature. Specifically, opening  170  can allow access to a surface of card  300 . Force can be applied to the surface of card  300  to extract card  300  out of throat  140  (shown in  FIG.  1   ) of attachable wallet  100 . That is, a user can extent a digit through opening  170  from a back of attachable wallet  100  to card  300  and apply a force to card  300  in order to extract card  300  from interior compartment  150 . Ferrite  610  (shown in  FIG.  3 C ) can be used to reduce magnetic flux that can otherwise pass through opening  170  to further improve shielding for card  300  when card  300  is in interior compartment  150  of attachable wallet  100 . Opening  170  can also be positioned such that it does not align with magnetic stripe  310  on card  300  when card  300  is located in interior compartment  150 . 
     In the manner described above, card  300  can be protected from magnetic flux generated by magnet array  190  an alignment magnet  192  when card  300  is located in interior compartment  150  of attachable wallet  100 . It can also be desirable to protect card  300  when card  300  is nearby, for example when card  300  is placed on a front surface of attachable wallet  100 . Accordingly, front panel  110  (shown in  FIG.  1   ) can further include shielding, such as shield layer  460  (shown in  FIG.  4   .) Examples of layers including shield layer  460  that can be used to form front panel  110  are shown below in  FIG.  4   . 
       FIG.  3 C  is another view of the subassembly of  FIG.  3 B . In this example, NFC inlay  620  and ferrite  610  can be located in central opening  182  of outer shunt  180  and in the center of magnet array  190 . Magnet array  190  can be attached to outer shunt  180  by adhesive layer  172 . Outer shunt  180  can be attached to inner shunt  160  using adhesive layer  176 . NFC inlay  620  and ferrite  610  can be located in opening  182  of outer shunt  180  and can be attached to inner shunt  160 , for example using an adhesive layer on a bottom surface of ferrite  610 . NFC inlay  620  can be attached to ferrite  610  by using, for example, an adhesive layer on a bottom surface of NFC inlay  620 . Further details of ferrite  610  are shown below in  FIG.  38   . 
     NFC inlay  620  can include NFC circuitry including but not limited to NFC coil  3710  (shown in  FIG.  36   ), capacitor  3820 , and capacitor  3830  (both shown in  FIG.  37   .) Capacitor  3820  and capacitor  3830  can be used with the inductance of NFC coil  3710  to tune a frequency response of NFC inlay  620 . That is, a frequency response of NFC inlay  620  (more specifically the NFC circuit of NFC inlay  620 ) can be tuned to receive an NFC signal from electronic device  200  (shown in  FIG.  1   .) 
     The presence of metal, particularly metal that forms a loop in parallel with NFC coil  3710 , can detune the frequency response of NFC inlay  620  and degrade the reception of an NFC signal from electronic device  200 . Accordingly, embodiments of the present invention can include shielding to isolate NFC inlay  620  from such metal loops. 
     Both inner shunt  160  and outer shunt  180  can form metal loops in parallel with NFC coil  3710 . Accordingly, inner shunt  160  can include break or gap  164 . Gap  164  can be an actual separation in inner shunt  160  where material from inner shunt  160  has been removed, gap  164  can be a section of nonconductive material inserted in an otherwise conductive plate, or gap  164  can be another structure. Gap  164  can be formed by stamping, cold working, laser ablation, or other technique. Gap  164  can help to prevent or reduce the formation of eddy currents in inner shunt  160  when NFC coil  3710  receives an NFC signal from electronic device  200 . This can help to prevent the NFC circuitry on NFC inlay  620  from being detuned by inner shunt  160 . Further ferrite  610  can be placed between NFC coil  3710  of NFC inlay  620  and inner shunt  160 . Ferrite  610  can help to shield NFC inlay  620  from inner shunt  160 . Ferrite  610  can help to prevent eddy currents from developing in inner shunt  160 , thereby limiting the amount inner shunt  160  can detune the NFC circuitry on NFC inlay  620 . 
     Similarly, outer shunt  180  can include gap  184 . Gap  184  can be an actual separation in outer shunt  180  where material from outer shunt  180  has been removed, gap  184  can be a section of nonconductive material inserted in an otherwise conductive plate, or gap  184  can be a different structure. Gap  184  can be formed by stamping, cold working, laser ablation, or other technique. Gap  184  can help to prevent or reduce the formation of eddy currents in outer shunt  180  when NFC coil  3710  receives an NFC signal from electronic device  200 . This can help to prevent the NFC circuitry on NFC inlay  620  from being detuned by outer shunt  180 . Further, ferrite  610  can be placed between NFC coil  3710  of NFC inlay  620  and outer shunt  180 . Ferrite  610  can help to shield NFC inlay  620  from outer shunt  180 . Ferrite  610  can help to prevent eddy currents from developing in outer shunt  180 , thereby limiting the amount outer shunt  180  can detune the NFC circuitry on NFC inlay  620 . 
     Attachable wallet  100  (shown in  FIG.  1   ) can be used to carry card  300  (shown in  FIG.  2   ), where card  300  is formed of metal. Accordingly, ferrite  610  can be placed between NFC inlay  620  and card  300 . Ferrite  610  can help to block an NFC signal from electronic device  200  from reaching card  300  and thereby detuning the NFC circuitry on NFC inlay  620 . That is, ferrite  610  can further help to prevent eddy currents from developing in card  300 , thereby helping to prevent the detuning of the NFC circuitry on NFC inlay  620 . Further details of the NFC circuitry and NFC inlay  620  are shown in  FIG.  36    below. 
     In these and other embodiments of the present invention, gap  164  and gap  184  can be positioned such that they are not aligned with each other. For example, gap  164  and gap  184  can be on opposite sides of opening  170 . This variation in positioning between gap  164  and gap  184  can help to provide a structure that can mechanically support ferrite  610  and NFC inlay  620 . In these and other embodiments of the present invention, it can be desirable to avoid shorting gap  164  with a portion of outer shunt  180 . Accordingly, adhesive layer  176  can be accurately positioned to prevent such shorting. This accurate positioning can be further used to avoid shorting gap  184  with a portion of inner shunt  160 . 
     In these and other embodiments of the present invention, it can be desirable to protect card  300  from magnet array  190 . It can also be desirable to direct magnetic flux from magnet array  190  towards electronic device  200 . Accordingly, inner shunt  160  and outer shunt  180  can be formed of metal, such as steel, 1085 steel, carbon steel, DT4 steel, or other type of steel or other material. Inner shunt  160  and outer shunt  180  can provide shielding between magnet array  190  and card  300 . Inner shunt  160  and outer shunt  180  can further direct magnetic flux from magnet array  190  towards electronic device  200 , thereby increasing the magnetic attraction between magnet array  190  and a corresponding magnet array in electronic device  200 . 
     In order to rotationally align attachable wallet  100  to electronic device  200 , alignment magnet  192  can be included. Alignment magnet  192  can be attached to the outer shunt  180  using adhesive layer  174 . Spring tab  162  can be stamped from inner shunt  160  leaving opening  163 . 
       FIG.  3 D  is a more detailed view of the subassembly of  FIG.  3 B . In this example, some of the constituent portions of NFC inlay  620  are shown. NFC inlay  620  can include NFC coil  3710  and flexible circuit board  3720 . NFC coil  3710  can be attached to shim  3730  with adhesive layer  3732 . Adhesive layer  3732  can attach the remainder of NFC inlay  620  to ferrite  610 . Ferrite  610  can include an adhesive layer (shown in  FIG.  38   ) on a bottom surface that can be used to attach ferrite  610  and NFC inlay  620  to inner shunt  160 . NFC inlay  620  and ferrite  610  can be positioned in opening  182  of outer shunt  180 . Outer shunt  180  can be attached to inner shunt  160  using adhesive layer  176 . Magnet array  190  can be attached to outer shunt  180  with adhesive layer  172  and alignment magnet  192  can be attached to outer shunt  180  with adhesive layer  174   
     In this example, capacitor  3820 , capacitor  3830 , and electronic circuit  3810  (all shown in  FIG.  37 A  and  FIG.  37 B ) can be located on a bottom side of flexible circuit board  3720 . Shim  3730  can include one or more openings, one or more notches, or both, for capacitor  3820 , capacitor  3030 , and electronic circuit  3810 , where details of one example are shown in  FIG.  37 A  and  FIG.  37 B . In this way, shim  3730  can help to protect capacitor  3820 , capacitor  3830 , and electronic circuit  3810 . Shim  3730  can further provide a flat surface at a back side of flexible circuit board  3720 , such that capacitor  3020 , capacitor  3830 , and electronic circuit  3810  do not form a visible or tactile impression at an outside surface of back panel  120  (shown in  FIG.  1   .) Spring tab  162  can be formed in inner shunt  160 , leaving opening  163 . Inner shunt  160  can include opening  170 . 
       FIG.  4    illustrates layers that can be utilized to form a front panel for an attachable wallet according to an embodiment of the present invention. In this example, an outside surface of front panel  110  can be formed by decorative layer  420 . Decorative layer  420  can be leather, or other material, such as a man-made leather substitute. Paint layer  410  can be a painted or decorative layer along an edge of decorative layer  420 . Shunt layer  440  can form a flexible shunt for shield layer  460 . Details of shield layer  460  are shown below in  FIG.  38   . Shield layer  460  can help to protect card  300  (or other structures) when card  300  is outside of attachable wallet  100  (shown in  FIG.  1   ) and is instead on top or near attachable wallet  100 . Shunt layer  450  can be a wrap-around flexible shunt or filler for shield layer  460 . Adhesive layer  430  can attach shunt layer  440  and shunt layer  450  to decorative layer  420 . Interior compartment  150  (shown in  FIG.  1   ) can be lined with taffeta or other material. Taffeta layer  480  can be attached to shield layer  460  with adhesive layer  470 . Taffeta layer  480  can be attached to taffeta layer  530  (shown in  FIG.  5   ) by adhesive or stitching layer  490 . Taffeta layer  480  and taffeta layer  530  can line interior compartment  150 . 
       FIG.  5    illustrates layers that can be utilized to form a portion of a back panel for an attachable wallet according to an embodiment of the present invention. In this example, layers  500  can include some of the layers between inner shunt  160  (shown in  FIG.  3 A ) and interior compartment  150  (shown in  FIG.  1   .) Layers  500  can include decorative layer  510 , which can be attached to taffeta layer  530  with adhesive layer  520 . Taffeta layer  530  and taffeta layer  480  (shown in  FIG.  4   ) can line interior compartment  150 . Decorative layer  510  can be formed of leather or other material. Decorative layer  510  can be formed of the same material as decorative layer  420  (shown in  FIG.  4   .) A rigid polycarbonate layer  540  can cover spring tab  162  (shown in  FIG.  2   .) Polycarbonate layer  540  can protect card  300  (shown in  FIG.  2   ) from marring when inserted into interior compartment  150  of attachable wallet  100  (shown in  FIG.  1   .) Filler layer  560  can be attached to inner shunt  160  in the subassembly shown in  FIG.  3 A . Filler layer  560  can be attached to taffeta layer  530  by adhesive layer  550 . Adhesive layer  550  can include portion  552  for attaching polycarbonate layer  540  to spring tab  162 . Adhesive layer  570  can attach filler layer  560  to inner shunt  160  in the subassembly shown in  FIG.  3 A . Passage or opening  170  can extend through layers  500 . 
       FIG.  6    and  FIG.  7    illustrate layers that can be utilized to form a portion of a back panel for an attachable wallet according to an embodiment of the present invention. In this example, layers  600  (shown in  FIG.  6   ) and layers  700  (shown in  FIG.  7   ) can include layers between outer shunt  180  (shown in  FIG.  3 A ) and an outside surface of back panel  120 . In  FIG.  6   , ferrite  610  can be a ferrite layer, further details of which are shown in  FIG.  38   . NFC inlay  620  and ferrite  610  can be around opening  170  (shown in  FIG.  3 A ) which can extend from an outside surface of back panel  120  to interior compartment  150 . Filler layer  640  can provide mechanical support. Filler layer  640  can be attached to inner shunt  160  of the subassembly shown in  FIG.  3 A  by adhesive layer  630  and to filler layer  660  with adhesive layer  650 . Filler layer  670  can also be included. Passage or opening  170  can extend through layers  600 . 
     In  FIG.  7   , polycarbonate layer  720  can be used as a stiffener. Polycarbonate layer  720  can be attached to filler layer  660  (shown in  FIG.  6   ) with adhesive layer  710 . Adhesive layer  730  can attach polycarbonate layer  720  to decorative layer  740 . Decorative layer  740  can be formed of leather or other material. Decorative layer  740  can be formed of the same material as decorative layer  420  in  FIG.  4    and decorative layer  510  in  FIG.  5   . Back panel  120  and front panel  110  can be stitched together with stitching  750 . Paint layer  760  and paint layer  770  can be painted layers for decorative purposes. Passage or opening  170  can extend through layers  700 . 
     In these and other embodiments of the present invention, near-field communication circuits, such as NFC coil  3710 , capacitor  3820 , capacitor  3830 , and tag or electronic circuit  3810  (all shown in  FIG.  36   ) can be included in attachable wallet  100 . This near-field communication circuit can be located on or near inner shunt  160  and outer shunt  180  (shown in  FIG.  3 A .) This arrangement can provide an accessory, such as attachable wallet  100 , that can be identified by an electronic device, such as electronic device  200  (shown in  FIG.  1   .) This identification can include electronic device  200  identifying that it is attached to an attachable wallet. This identification can include electronic device  200  identifying that it is attached to a specific attachable wallet. This identification can include electronic device  200  identifying that it is attached to a specific attachable wallet having specific characteristics or attributes, such as ownership, color, version, model, firmware, or other characteristics or attributes. 
     Once electronic device  200  identifies that it is attached to an accessory, such as attachable wallet  100 , electronic device  200  can commence various operations. These operations can include providing color graphics on a screen (not shown) of electronic device  200 , where a color in the color graphics has a relationship to a color of attachable wallet  100 , where the relationship is that the color is at least an approximate match, the color is a complementary color, the color is a contrasting color, or other relationship. These operations can include adjusting one or more lights, cameras, antennas, or other structures or components of electronic device  200 , where the structures or components are adjusted in response to the attachment (and therefore presence) of attachable wallet  100 . 
     For example, electronic device  200  can comprise a magnetometer (not shown.) The magnetometer can detect magnet array  190  in attachable wallet  100 . In response to this detection, electronic device  200  can generate a field using near-field communication circuitry (not shown). The near-field communication circuitry in electronic device  200  can detect this near-field communication circuitry in attachable wallet  100  and determine that it is attached to attachable wallet  100 . The near-field communication circuitry in attachable wallet  100  can include a tag or electronic circuit  3810 , and tag or electronic circuit  3810  can include identifying or other information that can be read by electronic device  200 . The near-field communication circuitry in electronic device  200  can also be used to detect a removal of an accessory such as attachable wallet  100  from the electronic device  200 . In response to detecting a disconnection, electronic device  200  can store the location of where the attachable wallet was detached, along with other information. 
     These and other embodiments of the present invention can provide an attachable wallet  100  that can further provide charging to an electronic device  200 . In such an attachable wallet  100 , a coil can be placed on or near either or both ferrite  610  and NFC inlay  620 . In such an attachable wallet  100 , a connector receptacle can also be included to receive power and data and to provide data. Simplified examples are shown in the following figures. 
     Described herein are various embodiments of magnetic alignment systems and components thereof. The magnetic alignment systems shown below can be used as magnet array  190  or as other magnet arrays and alignment magnets in other embodiments of the present invention. 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 an attachable wallet, which can be wireless charging device, and which might or might not surround an inductive charging coil, while the secondary annular alignment component is assumed to be in a portable electronic device, which might or might not surround 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 an attachable wallet, which can be wireless charging device. Also possible are “auxiliary” annular alignment components that are 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 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.  8    shows a simplified representation of a wireless charging system  800  incorporating a magnetic alignment system  806  according to some embodiments. A portable electronic device  804  is positioned on a charging surface  808  of a wireless charging device  802 . Portable electronic device  804  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. Electronic device  804  can be electronic device  200  (shown in  FIG.  1   .) Wireless charging device  802  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  802  can be attachable wallet  100  shown above in  FIG.  1   , wireless charging mat, puck, docking station, or the like. Wireless charging device  802  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  804  and wireless charging device  802  can include inductive coils  810  and  812 , respectively, which can operate to transfer power between them. For example, inductive coil  812  can be a transmitter coil that generates a time-varying magnetic flux  814 , and inductive coil  810  can be a receiver coil in which an electric current is induced in response to time-varying magnetic flux  814 . The received electric current can be used to charge a battery of portable electronic device  804 , to provide operating power to a component of portable electronic device  804 , 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  812  and  810 . According to some embodiments, magnetic alignment system  806  can provide such alignment. In the example shown in  FIG.  8   , magnetic alignment system  806  includes a primary magnetic alignment component  816  disposed within or on a surface of wireless charging device  802  and a secondary magnetic alignment component  818  disposed within or on a surface of portable electronic device  804 . Primary alignment components  816  and secondary alignment components  818  are configured to magnetically attract one another into an aligned position in which inductive coils  810  and  812  are aligned with one another to effectuate wireless power transfer. 
     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. 
     In this example, portable electronic device  804  can be a phone or other electronic device such as electronic device  200  in  FIG.  1   . Wireless charging device  802  can be an attachment device such as attachable wallet  100  in  FIG.  1   . Primary alignment components  816  can be used as magnet array  190  (shown in  FIG.  3 A ) or as a magnet array in other embodiments of the present invention. Inductive coil  812  can be optional where wireless charging device  802  is used as an attachable wallet, such as attachable wallet  100 . Inductive coil  812  can be used as a coil in these and other embodiments of the present invention. 
       FIG.  9 A  shows a perspective view of a magnetic alignment system  900  according to some embodiments, and  FIG.  9 B  shows a cross-section through magnetic alignment system  900  across the cut plane indicated in  FIG.  9 A . Magnetic alignment system  900  can be an implementation of magnetic alignment system  806  of  FIG.  8   . In magnetic alignment system  900 , 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  901  of magnetic alignment system  900 , and a transverse plane (also referred to as a “lateral” or “x” or “y” direction) is defined to be normal to axis  901 . 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.  9 A , magnetic alignment system  900  can include a primary alignment component  916  (which can be an implementation of primary alignment component  816  of  FIG.  8   ) and a secondary alignment component  918  (which can be an implementation of secondary alignment component  818  of  FIG.  8   ). Primary alignment component  916  and secondary alignment component  918  have annular shapes and can also be referred to as “annular” alignment components. The particular dimensions can be chosen as desired. In some embodiments, primary alignment component  916  and secondary alignment component  918  can each have an outer diameter of about 124 mm and a radial width of about 6 mm. The outer diameters and radial widths of primary alignment component  916  and secondary alignment component  918  need not be exactly equal. For instance, the radial width of secondary alignment component  918  can be slightly less than the radial width of primary alignment component  916  and/or the outer diameter of secondary alignment component  918  can also be slightly less than the radial width of primary alignment component  916  so that, when in alignment, the inner and outer sides of primary alignment component  916  extend beyond the corresponding inner and outer sides of secondary alignment component  918 . Thicknesses (or axial dimensions) of primary alignment component  916  and secondary alignment component  918  can also be chosen as desired. In some embodiments, primary alignment component  916  has a thickness of about 1.5 mm while secondary alignment component  918  has a thickness of about 0.37 mm. 
     Primary alignment component  916  can include a number of sectors, each of which can be formed of one or more primary arcuate magnets  926 , and secondary alignment component  918  can include a number of sectors, each of which can be formed of one or more secondary arcuate magnets  928 . In the example shown, the number of primary magnets  926  is equal to the number of secondary magnets  928 , and each sector includes exactly one magnet, but this is not required. Primary magnets  926  and secondary magnets  928  can have arcuate (or curved) shapes in the transverse plane such that when primary magnets  926  (or secondary magnets  928 ) are positioned adjacent to one another end-to-end, primary magnets  926  (or secondary magnets  928 ) form an annular structure as shown. In some embodiments, primary magnets  926  can be in contact with each other at interfaces  930 , and secondary magnets  928  can be in contact with each other at interfaces  932 . Alternatively, small gaps or spaces can separate adjacent primary magnets  926  or secondary magnets  928 , providing a greater degree of tolerance during manufacturing. 
     In some embodiments, primary alignment component  916  can also include an annular shield  914  disposed on a distal surface of primary magnets  926 . In some embodiments, shield  914  can be formed as a single annular piece of material and adhered to primary magnets  926  to secure primary magnets  926  into position. Shield  914  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  916 , thereby protecting sensitive electronic components located beyond the distal side of primary alignment component  916  from magnetic interference. 
     Primary magnets  926  and secondary magnets  928  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  926  and each secondary magnet  928  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  915 ,  917  in  FIG.  9 B . For example, each primary magnet  926  and each secondary magnet  928  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  926  has its north pole oriented toward the proximal surface and south pole oriented toward the distal surface while secondary magnet  928  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  926  has its south pole oriented toward the proximal surface and north pole oriented toward the distal surface while secondary magnet  928  has its north pole oriented toward the proximal surface and south pole oriented toward the distal surface. 
     As shown in  FIG.  9 B , the axial magnetic orientation of primary magnet  926  and secondary magnet  928  can generate magnetic fields  940  that generate an attractive force between primary magnet  926  and secondary magnet  928 , thereby facilitating alignment between respective electronic devices in which primary alignment component  916  and secondary alignment component  918  are disposed (e.g., as shown in  FIG.  8   ). While shield  914  can redirect some of magnetic fields  940  away from regions below primary magnet  926 , magnetic fields  940  can still propagate to regions laterally adjacent to primary magnet  926  and secondary magnet  928 . In some embodiments, the lateral propagation of magnetic fields  940  can 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  916  (or secondary alignment component  918 ), leakage of magnetic fields  940  can saturate the ferrimagnetic shield, which can degrade wireless charging performance. 
     It will be appreciated that magnetic alignment system  900  is illustrative and that variations and modifications are possible. For instance, while primary alignment component  916  and secondary alignment component  918  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  916  and/or secondary alignment component  918  can each be formed of a single, monolithic annular magnet; however, segmenting magnetic alignment components  916  and  918  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.  9 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.  10 A  shows a perspective view of a magnetic alignment system  1000  according to some embodiments, and  FIG.  10 B  shows a cross-section through magnetic alignment system  1000  across the cut plane indicated in  FIG.  10 A . Magnetic alignment system  1000  can be an implementation of magnetic alignment system  806  of  FIG.  8   . In magnetic alignment system  1000 , the alignment components have magnetic components configured in a “closed loop” configuration as described below. 
     As shown in  FIG.  10 A , magnetic alignment system  1000  can include a primary alignment component  1016  (which can be an implementation of primary alignment component  816  of  FIG.  8   ) and a secondary alignment component  1018  (which can be an implementation of secondary alignment component  818  of  FIG.  8   ). Primary alignment component  1016  and secondary alignment component  1018  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  1016  and secondary alignment component  1018  can each have an outer diameter of about 124 mm and a radial width of about 6 mm. The outer diameters and radial widths of primary alignment component  1016  and secondary alignment component  1018  need not be exactly equal. For instance, the radial width of secondary alignment component  1018  can be slightly less than the radial width of primary alignment component  1016  and/or the outer diameter of secondary alignment component  1018  can also be slightly less than the radial width of primary alignment component  1016  so that, when in alignment, the inner and outer sides of primary alignment component  1016  extend beyond the corresponding inner and outer sides of secondary alignment component  1018 . Thicknesses (or axial dimensions) of primary alignment component  1016  and secondary alignment component  1018  can also be chosen as desired. In some embodiments, primary alignment component  1016  has a thickness of about 1.5 mm while secondary alignment component  1018  has a thickness of about 0.37 mm. 
     Primary alignment component  1016  can include a number of sectors, each of which can be formed of a number of primary magnets  1026 , and secondary alignment component  1018  can include a number of sectors, each of which can be formed of a number of secondary magnets  1028 . In the example shown, the number of primary magnets  1026  is equal to the number of secondary magnets  1028 , 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  1026  and secondary magnets  1028  can have arcuate (or curved) shapes in the transverse plane such that when primary magnets  1026  (or secondary magnets  1028 ) are positioned adjacent to one another end-to-end, primary magnets  1026  (or secondary magnets  1028 ) form an annular structure as shown. In some embodiments, primary magnets  1026  can be in contact with each other at interfaces  1030 , and secondary magnets  1028  can be in contact with each other at interfaces  1032 . Alternatively, small gaps or spaces may separate adjacent primary magnets  1026  or secondary magnets  1028 , providing a greater degree of tolerance during manufacturing. 
     In some embodiments, primary alignment component  1016  can also include an annular shield  1014  disposed on a distal surface of primary magnets  1026 . In some embodiments, shield  1014  can be formed as a single annular piece of material and adhered to primary magnets  1026  to secure primary magnets  1026  into position. Shield  1014  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  1016 , thereby protecting sensitive electronic components located beyond the distal side of primary alignment component  1016  from magnetic interference. 
     Primary magnets  1026  and secondary magnets  1028  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  1028  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  1017  in  FIG.  10 B ). As described below, the magnetic orientation can be in a radial direction with respect to axis  1001  or another direction having a radial component in the transverse plane. Each primary magnet  1026  can include two magnetic regions having opposite magnetic orientations. For example, each primary magnet  1026  can include an inner arcuate magnetic region  1052  having a magnetic orientation in a first axial direction (as shown by polarity indicator  1053  in  FIG.  10 B ), an outer arcuate magnetic region  1054  having a magnetic orientation in a second axial direction opposite the first direction (as shown by polarity indicator  1055  in  FIG.  10 B ), and a central non-magnetized region  1056  that does not have a magnetic orientation. Central non-magnetized region  1056  can magnetically separate inner arcuate region  1052  from outer arcuate region  1054  by inhibiting magnetic fields from directly crossing through central region  1056 . 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  1028  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  1026  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  1026  can be a compound structure with two arcuate pieces of magnetic material providing inner arcuate magnetic region  1052  and outer arcuate magnetic region  1054 ; in such embodiments, central non-magnetized region  1056  can be formed of an arcuate piece of nonmagnetic material or formed as an air gap defined by sidewalls of inner arcuate magnetic region  1052  and outer arcuate magnetic region  1054 . 
     As shown in  FIG.  10 B , the magnetic polarity of secondary magnet  1028  (shown by indicator  1017 ) can be oriented such that when primary alignment component  1016  and secondary alignment component  1018  are aligned, the south pole of secondary magnet  1028  is oriented toward the north pole of inner arcuate magnetic region  1052  (shown by indicator  1053 ) while the north pole of secondary magnet  1028  is oriented toward the south pole of outer arcuate magnetic region  1054  (shown by indicator  1055 ). Accordingly, the respective magnetic orientations of inner arcuate magnetic region  1052 , secondary magnet  1028  and outer arcuate magnetic region  1056  can generate magnetic fields  1040  that produce an attractive force between primary magnet  1026  and secondary magnet  1028 , thereby facilitating alignment between respective electronic devices in which primary alignment component  1016  and secondary alignment component  1018  are disposed (e.g., as shown in  FIG.  8   ). Shield  1014  can redirect some of magnetic fields  1040  away from regions below primary magnet  1026 . Further, the “closed-loop” magnetic field  1040  formed around central nonmagnetic region  1056  can have tight and compact field lines that do not stray from primary and secondary magnets  1026  and  1028  as far as magnetic field  1040  strays from primary and secondary magnets  1076  and  1078  in  FIG.  10 B . Thus, magnetically sensitive components can be placed relatively close to primary alignment component  1016  with reduced concern for stray magnetic fields. Accordingly, as compared to magnetic alignment system  1050 , magnetic alignment system  1000  can help to reduce the overall size of a device in which primary alignment component  1016  is positioned and can also help reduce noise created by magnetic field  1040  in adjacent components or devices, such as a power-receiving device in which secondary alignment component  1018  is positioned. 
     It will be appreciated that magnetic alignment system  1000  is illustrative and that variations and modifications are possible. For instance, while primary alignment component  1016  and secondary alignment component  1018  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  1018  can be formed of a single, monolithic annular magnet. Similarly, primary alignment component  1016  can be formed of a single, monolithic annular piece of magnetic material with an appropriate magnetization pattern as described above, or primary alignment component  1016  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  1000 , secondary alignment component  1018  can have a magnetic orientation in the transverse plane. For example, in some embodiments, secondary alignment component  1018  can have a magnetic polarity in a radial orientation.  FIG.  11    shows a simplified top-down view of a secondary alignment component  1118  according to some embodiments having secondary magnets  1128   a - h  with radial magnetic orientations as shown by magnetic polarity indicators  1117   a - h . In this example, each secondary magnet  1128   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  1128   a - h  can be oriented toward the radially inward side while the south magnetic pole is oriented toward the radially outward side. 
       FIG.  12 A  shows a perspective view of a magnetic alignment system  1200  according to some embodiments. Magnetic alignment system  1200 , which can be an implementation of magnetic alignment system  1000 , includes a secondary alignment component  1218  having a radially outward magnetic orientation (e.g., as shown in  FIG.  11   ) and a complementary primary alignment component  1216 . In this example, magnetic alignment system  1200  includes a gap  1219  between two of the sectors; however, gap  1219  is optional and magnetic alignment system  1200  can be a complete annular structure. Also shown are components  1202 , which can include, for example an inductive coil assembly or other components located within the central region of primary magnetic alignment component  1216  or secondary magnetic alignment component  1218 . Magnetic alignment system  1200  can have a closed-loop configuration similar to magnetic alignment system  1000  (as shown in  FIG.  10 B ) and can include arcuate sectors  1201 , each of which can be made of one or more arcuate magnets. In some embodiments, the closed-loop configuration of magnetic alignment system  1200  can reduce or prevent magnetic field leakage that may affect components  1202 . 
       FIG.  12 B  shows an axial cross-section view through one of arcuate sectors  1201 . Arcuate sector  1201  includes a primary magnet  1226  and a secondary magnet  1228 . As shown by orientation indicator  1217 , secondary magnet  1228  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  1200 . Like primary magnets  1026  described above, primary magnet  1226  includes an inner arcuate magnetic region  1252 , an outer arcuate magnetic region  1254 , and a central non-magnetized region  1256  (which can include, e.g., an air gap or a region of nonmagnetic or non-magnetized material). Inner arcuate magnetic region  1252  has a magnetic polarity oriented axially such that the north magnetic pole is toward secondary magnet  1228 , as shown by indicator  1253 , while outer arcuate magnetic region  1254  has an opposite magnetic orientation, with the south magnetic pole oriented toward secondary magnet  1228 , as shown by indicator  1255 . As described above with reference to  FIG.  15 B , the arrangement of magnetic orientations shown in  FIG.  12 B  results in magnetic attraction between primary magnet  1226  and secondary magnet  1228 . In some embodiments, the magnetic polarities can be reversed such that the north magnetic pole of secondary magnet  1228  is oriented toward the radially inward side of magnetic alignment system  1200 , the north magnetic pole of outer arcuate region  1254  of primary magnet  1226  is oriented toward secondary magnet  1228 , and the north magnetic pole of inner arcuate region  1252  is oriented away from secondary magnet  1228 . 
     When primary alignment component  1216  and secondary alignment component  1218  are aligned, the radially symmetrical arrangement and directional equivalence of magnetic polarities of primary alignment component  1216  and secondary alignment component  1218  allow secondary alignment component  1218  to rotate freely (relative to primary alignment component  1216 ) 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.  12 C  shows a secondary arcuate magnet  1238  according to some embodiments. Secondary arcuate magnet  1238  has a purely radial magnetic orientation, as indicated by arrows  1239 . Each arrow  1239  is directed at the center of curvature of magnet  1238 ; if extended inward, arrows  1239  would converge at the center of curvature. However, achieving this purely radial magnetization requires that magnetic domains within magnet  1238  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.  12 C .  FIG.  12 D  shows a secondary arcuate magnet  1248  with pseudo-radial magnetic orientation according to some embodiments. Magnet  1248  has a magnetic orientation, shown by arrows  1249 , that is perpendicular to a baseline  1251  connecting the inner corners  1257 ,  1259  of arcuate magnet  1248 . If extended inward, arrows  1249  would not converge. Thus, neighboring magnetic domains in magnet  1248  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.  12 C .  FIG.  12 E  shows a secondary annular alignment component  1258  made up of magnets  1248  according to some embodiments. Magnetic orientation arrows  1249  have been extended to the center point  1261  of annular alignment component  1258 . As shown the magnetic field direction can be approximately radial, with the closeness of the approximation depending on the number of magnets  1248  and the inner radius of annular alignment component  1258 . In some embodiments, 138 magnets  1248  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  1218  (e.g., as shown in  FIG.  12 B ) provides a magnetic force profile between secondary alignment component  1218  and primary alignment component  1216  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  1218  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.  13 A and  13 B  show graphs of force profiles for different magnetic alignment systems, according to some embodiments. Specifically,  FIG.  13 A  shows a graph  1300  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  1300  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  1300  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  1301  (dot-dash line). A second type of magnetic alignment system uses annular alignment components with axial magnetic orientations, e.g., magnetic alignment system  900  of  FIGS.  9 A and  9 B ; a representative normal force profile for such an annular-axial magnetic alignment system is shown as line  1303  (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  1200  of  FIG.  12   ); a representative normal force profile for a radially symmetric closed-loop magnetic alignment system is shown as line  1305  (solid line). 
     Similarly,  FIG.  13 B  shows a graph  1320  of lateral (shear) force in a transverse direction for different magnetic alignment systems. Graph  1320  has a horizontal axis representing displacement from a center of alignment using the same convention and units as graph  1300 , 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  1320  shows shear force profiles for the same three types of magnetic alignment systems as graph  1300 : a representative shear force profile for a central magnetic alignment system is shown as line  1321  (dot-dash line); a representative shear force profile for an annular-axial magnetic alignment system is shown as line  1323  (dashed line); and a representative normal force profile for a radially symmetric closed-loop magnetic alignment system is shown as line  1325  (solid line). 
     As shown in  FIG.  13 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  1311 ,  1313 , and  1315 . 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  1200  of  FIG.  12   ) 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.  13 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  1331   a - b ,  1333   a - b , and  1335   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  1200  of  FIG.  12   ) 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  1200  of  FIG.  12   ) 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.  14    shows a simplified top-down view of a secondary alignment component  1418  according to some embodiments. Secondary alignment component  1418  includes sectors  1428   a - h  with radial magnetic orientations as shown by magnetic polarity indicators  1417   a - h . Each of sectors  1428   a - h  can include one or more secondary arcuate magnets (not shown). In this example, secondary magnets in sectors  1428   b ,  1428   d ,  1428   f , and  1428   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  1428   a ,  1428   c ,  1428   e , and  1428   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  1428   a - h  of secondary alignment component  1418  have alternating magnetic orientations. A complementary primary alignment component can have sectors with correspondingly alternating magnetic orientations. 
     For example,  FIG.  15 A  shows a perspective view of a magnetic alignment system  1500  according to some embodiments. Magnetic alignment system  1500  includes a secondary alignment component  1518  having alternating radial magnetic orientations (e.g., as shown in  FIG.  14   ) and a complementary primary alignment component  1516 . Some of the arcuate sections of magnetic alignment system  1500  are not shown in order to reveal internal structure; however, it should be understood that magnetic alignment system  1500  can be a complete annular structure. Also shown are components  1502 , which can include, for example, inductive coil assemblies or other components located within the central region of primary annular alignment component  1516  and/or secondary annular alignment component  1518 . Magnetic alignment system  1500  can be a closed-loop magnetic alignment system similar to magnetic alignment system  1000  described above and can include arcuate sectors  1501   b ,  1501   c  of alternating magnetic orientations, with each arcuate sector  1501   b ,  1501   c  including one or more arcuate magnets in each of primary annular alignment component  1516  and secondary annular alignment component  1518 . In some embodiments, the closed-loop configuration of magnetic alignment system  1500  can reduce or prevent magnetic field leakage that may affect component  1502 . 
       FIG.  15 B  shows an axial cross-section view through one of arcuate sectors  1501   b , and  FIG.  15 C  shows an axial cross-section view through one of arcuate sectors  1501   c . Arcuate sector  1501   b  includes a primary magnet  1526   b  and a secondary magnet  1528   b . As shown by orientation indicator  1517   b , secondary magnet  1528   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  1500 . Like primary magnets  1026  described above, primary magnet  1526   b  includes an inner arcuate magnetic region  1552   b , an outer arcuate magnetic region  1554   b , and a central nonmagnetic region  1556   b  (which can include, e.g., an air gap or a region of nonmagnetic material). Inner arcuate magnetic region  1552   b  has a magnetic polarity oriented axially such that the north magnetic pole is toward secondary magnet  1528   b , as shown by indicator  1553   b , while outer arcuate magnetic region  1554   b  has an opposite magnetic orientation, with the south magnetic pole oriented toward secondary magnet  1528   b , as shown by indicator  1555   b . As described above with reference to  FIG.  10 B , the arrangement of magnetic orientations shown in  FIG.  15 B  results in magnetic attraction between primary magnet  1526   b  and secondary magnet  1528   b.    
     As shown in  FIG.  15 C , arcuate sector  1501   c  has a “reversed” magnetic orientation relative to arcuate sector  1501   b . Arcuate sector  1501   c  includes a primary magnet  1526   c  and a secondary magnet  1528   c . As shown by orientation indicator  1517   c , secondary magnet  1528   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  1500 . Like primary magnets  1026  described above, primary magnet  1526   c  includes an inner arcuate magnetic region  1552   c , an outer arcuate magnetic region  1554   c , and a central nonmagnetic region  1556   c  (which can include, e.g., an air gap or a region of nonmagnetic material). Inner arcuate magnetic region  1552   c  has a magnetic polarity oriented axially such that the south magnetic pole is toward secondary magnet  1528   c , as shown by indicator  1553   c , while outer arcuate magnetic region  1554   c  has an opposite magnetic orientation, with the north magnetic pole oriented toward secondary magnet  1528   c , as shown by indicator  1555   c . As described above with reference to  FIG.  10 B , the arrangement of magnetic orientations shown in  FIG.  15 C  results in magnetic attraction between primary magnet  1526   c  and secondary magnet  1528   c.    
     An alternating arrangement of magnetic polarities as shown in  FIGS.  14  and  15 A- 20 C  can create a “ratcheting” feel when secondary alignment component  1518  is aligned with primary alignment component  1516  and one of alignment components  1516 ,  1518  is rotated relative to the other about the common axis. For instance, as secondary alignment component  1518  is rotated relative to primary alignment component  1516 , radially-outward secondary magnet  1528   b  alternately come into proximity with a complementary primary magnet  1526   b  of primary alignment component  1516 , resulting in an attractive magnetic force, and with an anti-complementary magnet  1526   c  of primary alignment component  1516 , resulting in a repulsive magnetic force. If primary magnets  1526   b ,  1526   c  and secondary magnets  1528   b ,  1528   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 pairs of magnets  1526   b ,  1528   b  and  1526   c ,  1528   c  are in proximity. In other rotational orientations, a torque toward a stable rotational orientation can be experienced. 
     In the examples shown in  FIGS.  14  and  15 A through  15 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.  16 A  shows a simplified top-down view of a secondary alignment component  1618  according to some embodiments. Secondary alignment component  1618  includes secondary magnets  1628   b  with radially outward magnetic orientations and secondary magnets  1628   c  with radially inward orientations, similarly to secondary alignment component  1518  described above. In this example, the magnets are arranged such that a pair of outwardly-oriented magnets  1628   b  (forming a first sector) are adjacent to a pair of inwardly-oriented magnets  1628   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  1618 . Similarly,  FIG.  16 B  shows a simplified top-down view of another secondary alignment component  1618 ′ according to some embodiments. Secondary alignment component  1618 ′ includes secondary magnets  1628   b  with radially outward magnetic orientations and secondary magnets  1628   c  with radially inward orientations. In this example, the magnets are arranged such that a group of four radially-outward magnets  1628   b  (forming a first sector) is adjacent to a group of four radially-inward magnets  1628   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  1618 ′. Although not shown in  FIGS.  16 A and  16 B , the structure of a complementary primary alignment component for secondary alignment component  1618  or  1618 ′ should be apparent in view of  FIGS.  15 A- 20 C . A shear force profile for the alignment components of  FIGS.  16 A and  16 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.  17    shows a simplified top-down view of a secondary alignment component  1718  according to some embodiments having sectors  1728   a - h  with location-dependent magnetic orientations as shown by magnetic polarity indicators  1717   a - h . In this example, secondary alignment component  1718  can be regarded as bisected by bisector line  1701 , which defines two halves of secondary alignment component  1718 . In a first half  1703 , sectors  1728   e - h  have magnetic polarities oriented radially outward, similarly to examples described above. 
     In the second half-annulus  1705 , sectors  1728   a - d  have magnetic polarities oriented substantially parallel to bisector line  1701  rather than radially. In particular, sectors  1728   a  and  1728   b  have magnetic polarities oriented in a first direction parallel to bisector line  1701 , while sectors  1728   c  and  1728   d  have magnetic polarities oriented in the direction opposite to the direction of the magnetic polarities of sectors  1728   a  and  1728   b . A complementary primary alignment component can have an inner annular region with magnetic north pole oriented toward secondary alignment component  1718 , an outer annular region with magnetic north pole oriented away from secondary alignment component  1718 , 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  1718  can modify the shear force profile such that secondary alignment component  1718  generates less shear force in the direction toward second half-annulus  1705  than in the direction toward first half  1703 . 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  1718  is oriented in the portable electronic device such that half-annulus  1705  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 various embodiments described above, a magnetic alignment system can provide robust alignment in a lateral plane and may or may not provide rotational alignment. For example, radially symmetric magnetic alignment system  1200  of  FIGS.  12 A- 17 B  may not define a preferred rotational orientation. Radially alternating magnetic alignment system  1500  of  FIGS.  15 A- 20 C  can define multiple equally preferred rotational orientations. For some applications, such as alignment of a portable electronic device with a wireless charging puck, rotational orientation may not be a concern. In other applications, such as alignment of a portable electronic device in attachable wallet  100  (shown above) a docking station or upright holder, a particular rotational alignment may be desirable. Accordingly, in some embodiments an annular magnetic alignment system can be augmented with one or more rotational alignment components that can be positioned externally to and spaced apart from the annular magnetic alignment components to help guide devices into a target rotational orientation relative to each other. 
       FIG.  18    shows an example of a magnetic alignment system with an annular alignment component and a rotational alignment component according to some embodiments. In this example, primary alignment components of the magnetic alignment system are included in an accessory device  1802 , and secondary alignment components of the magnetic alignment system are included in a portable electronic device  1804 . Portable electronic device  1804  can be, for example, a smart phone whose front surface provides a touchscreen display and whose back surface is designed to support wireless charging. Accessory device  1802  can be, for example, a charging dock that supports portable electronic device  1804  such that its display is visible and accessible to a user.  FIG.  18    shows proximal surfaces of portable electronic device  1804  and accessory device  1802 . For instance, accessory device  1802  can support portable electronic device  1804  such that the display is vertical or at a conveniently tilted angle for viewing and/or touching. In the example shown, accessory device  1802  supports portable electronic device  1804  in a “portrait” orientation (shorter sides of the display at the top and bottom); however, in some embodiments accessory device  1802  can support portable electronic device  1804  in a “landscape” orientation (longer sides of the display at the top and bottom). Accessory device  1802  can also be mounted on a swivel, gimbal, or the like, allowing the user to adjust the orientation of portable electronic device  1804  by adjusting the orientation of accessory device  1802 . 
     Accessory device  1802  can be used as all or part of attachable wallet  100  shown above, or as all or part of another attachable wallet according to an embodiment of the present invention. 
     As described above, components of a magnetic alignment system can include a primary annular alignment component  1816  disposed in accessory device  1802  and a secondary annular alignment component  1818  disposed in portable electronic device. Primary annular alignment component  1816  can be similar or identical to any of the primary alignment components described above. For example, primary annular alignment component  1816  can be formed of arcuate magnets  1826  arranged in an annular configuration. Although not shown in  FIG.  18   , one or more gaps can be provided in primary annular alignment component  1816 , e.g., by omitting one or more of arcuate magnets  1826  or by providing a gap at one or more interfaces  1830  between adjacent arcuate magnets  1826 . In some embodiments, each arcuate magnet  1826  can include an inner region having a first magnetic orientation (e.g., axially oriented in a first direction) and an outer region having a second magnetic orientation opposite the first magnetic orientation (e.g., axially oriented opposite the first direction), with a non-magnetized gap region between the inner and outer regions (which can include an air gap or a nonmagnetic material). In some embodiments, primary annular alignment component can also include a shield (not shown) on the distal side of arcuate magnets  1826 . 
     Likewise, secondary annular alignment component  1818  can be similar or identical to any of the secondary alignment components described above. For example, secondary annular alignment component  1818  can be formed of arcuate magnets  1828  arranged in an annular configuration. Although not shown in  FIG.  18   , one or more gaps can be provided in secondary annular alignment component  1818 , e.g., by omitting one or more arcuate magnets  1828  or by providing a gap at one or more interfaces  1832  between adjacent magnets  1828 . As described above, arcuate magnets  1828  can provide radially-oriented magnetic polarities. For instance, all sectors of secondary annular alignment component  1818  can have a radially-outward magnetic orientation or a radially-inward magnetic orientation, or some sectors of secondary annular alignment component  1818  may have a radially-outward magnetic orientation while other sectors of secondary annular alignment component  1818  have a radially-inward magnetic orientation. 
     As described above, primary annular alignment component  1816  and secondary annular alignment component  1818  can provide shear forces that promote alignment in the lateral plane so that center point  1801  of primary annular alignment component  1816  aligns with center point  1803  of secondary annular alignment component  1818 . However, primary annular alignment component  1816  and secondary annular alignment component  1818  might not provide shear forces that favor any particular rotational orientation, such as portrait orientation. 
     Accordingly, in some embodiments, a magnetic alignment system can incorporate one or more rotational alignment components in addition to the annular alignment components. The rotational alignment components can include one or more magnets that provide torque about the common axis of the (aligned) annular alignment components, so that a preferred rotational orientation can be reliably established. For example, as shown in  FIG.  18   , a primary rotational alignment component  1822  can be disposed outside of and spaced apart from primary annular alignment component  1816  while a secondary rotational alignment component  1824  is disposed outside of and spaced apart from secondary annular alignment component  1818 . Secondary rotational alignment component  1824  can be positioned at a fixed distance (y 0 ) from center point  1803  of secondary annular alignment component  1818  and centered between the side edges of portable electronic device  1804  (as indicated by distance xo from either side edge). Similarly, primary rotational alignment component  1822  can be positioned at the same distance y 0  from center point  1801  of primary annular alignment component  1816  and located at a rotational angle that results in a torque profile that favors the desired orientation of portable electronic device  1804  relative to accessory device  1802  when secondary rotational alignment component  1824  is aligned with primary rotational alignment component  1822 . It should be noted that the same distance y 0  can be applied in a variety of portable electronic devices having different form factors, so that a single accessory can be compatible with a family of portable electronic devices. A longer distance y 0  can increase torque toward the preferred rotational alignment; however, the maximum distance y 0  may be limited by design considerations, such as the size of the smallest portable electronic device in a family of portable electronic devices that incorporate mutually compatible magnetic alignment systems. 
     According to some embodiments, each of primary rotational alignment component  1822  and secondary rotational alignment component  1824  can be implemented using one or more rectangular or square blocks of magnetic material each of which has each been magnetized such that its magnetic polarity is oriented in a desired direction. The magnetic orientations of rotational alignment components  1822  and  1824  can be complementary so that an attractive magnetic force is generated when the proximal surfaces of rotational alignment components  1822  and  1824  are near each other. This attractive magnetic force can help to rotate portable electronic device  1804  and accessory device  1802  into a preferred rotational orientation in which the proximal surfaces of rotational alignment components  1822  and  1824  are in closest proximity to each other. Examples of magnetic orientations for rotational alignment components  1822  and  1824  that can be used to provide a desired attractive force are described below. In some embodiments, primary rotational alignment component  1822  and secondary rotational alignment component  1824  can have the same lateral dimensions and the same thickness. The dimensions can be chosen based on a desired magnetic field strength, the dimensions of devices in which the rotational alignment components are to be deployed, and other design considerations. In some embodiments, the lateral dimensions can be about 6 mm by about 18 mm, and the thickness can be anywhere from about 0.3 mm to about 1.5 mm. In some embodiments, each of primary rotational alignment component  1822  and secondary rotational alignment component  1824  can be implemented using multiple rectangular blocks of magnetic material positioned adjacent to each other. As in other embodiments, a small gap may be present between adjacent magnets, e.g., due to manufacturing tolerances. 
       FIGS.  19 A and  19 B  show an example of rotational alignment according to some embodiments. In  FIG.  19 A , accessory device  1802  is placed on the back surface of portable electronic device  1804  such that primary annular alignment component  1816  and secondary alignment component  1818  are aligned with each other in the lateral plane (which is the plane of the page in  FIG.  19 A ); in the view shown, center point  1801  of primary annular alignment component  1816  overlies center point  1803  of secondary annular alignment component  1818  A relative rotation is present such that rotational alignment components  1822  and  1824  are not aligned. In this configuration, an attractive force between rotational alignment components  1822  and  1824  can help guide portable electronic device  1804  and accessory device  1802  into a target rotational orientation as shown in  FIG.  12 B . In  FIG.  19 B , the attractive magnetic force between rotational alignment components  1822  and  1824  has brought portable electronic device  1804  and accessory device  1802  into the target rotational alignment with the sides of portable electronic device  1804  parallel to the sides of accessory device  1802 . In some embodiments, the same attractive magnetic force between rotational alignment components  1822  and  1824  can help to hold portable electronic device  1804  and accessory device  1802  in a fixed rotational alignment. 
     Rotational alignment components  1822  and  1824  can have various patterns of magnetic orientations. As long as the magnetic orientations of rotational alignment components  1822  and  1824  are complementary to each other, a torque toward the target rotational orientation can be present when the devices are brought into lateral alignment and close to the target rotational orientation.  FIGS.  20 A- 28 B  show examples of magnetic orientations for a rotational alignment component according to various embodiments. While the magnetic orientation is shown for only one rotational alignment component, it should be understood that the magnetic orientation of a complementary rotational alignment component can be complementary to (e.g., the reverse of) the magnetic orientation of shown. 
       FIGS.  20 A and  20 B  show a perspective view and a top view of a rotational alignment component  2024  having a “z-pole” configuration according to some embodiments. It should be understood that the perspective view is not to any particular scale and that the lateral (xy) dimensions and axial (z) thickness can be varied as desired. As shown in  FIG.  20 A , rotational alignment component  2024  can have a uniform magnetic orientation along the axial direction, as indicated by arrows  2005 . Accordingly, as shown in  FIG.  20 B , a north magnetic pole (N) may be nearest the proximal surface  2003  of rotational alignment component  2024 . A complementary z-pole alignment component can have a uniform magnetic orientation with a south magnetic pole nearest the proximal surface. The z-pole configuration can provide reliable alignment. 
     Other configurations can provide reliable alignment as well as a stronger, or more salient, “clocking” sensation for the user. A “clocking sensation,” as used herein, refers to a user-perceptible torque about the common axis of the annular alignment components that pulls toward the target rotational alignment and/or resists small displacements from the target rotational alignment. A greater variation of torque as a function of rotational angle can provide a more salient clocking sensation. Following are examples of magnetization configurations for a rotational alignment component that can provide more salient clocking sensations than the z-pole configuration of  FIGS.  20 A and  20 B . 
       FIGS.  21 A and  21 B  show a perspective view and a top view of a rotational alignment component  2124  having a “quad pole” configuration according to some embodiments. It should be understood that the perspective view is not to any particular scale and that the lateral (xy) dimensions and axial (z) thickness can be varied as desired. As shown in  FIG.  21 A , rotational alignment component  2124  has a first magnetized region  2125  with a magnetic orientation along the axial direction such that the north magnetic pole (N) is nearest the proximal (+z) surface  2103  of rotational alignment component  2124  (as indicated by arrow  2105 ) and a second magnetized region  2127  with a magnetic orientation opposite to the magnetic orientation of the first region such that the south magnetic pole (S) is nearest to proximal surface  2103  (as indicated by arrows  2107 ). Between magnetized regions  2125  and  2127  is a neutral region  2129  that is not magnetized. In some embodiments, rotational alignment component  2124  can be formed from a single piece of magnetic material that is exposed to a magnetizer to create regions  2125 ,  2127 ,  2129 . Alternatively, rotational alignment component  2124  can be formed using two pieces of magnetic material with a nonmagnetic material or an air gap between them. As shown in  FIG.  21 B , the proximal surface of rotational alignment component  2124  can have one region having a “north” polarity and another region having a “south” polarity. A complementary quad-pole rotational alignment component can have corresponding regions of south and north polarity at the proximal surface. 
       FIGS.  22 A and  22 B  show a perspective view and a top view of a rotational alignment component  2224  having an “annulus design” configuration according to some embodiments. It should be understood that the perspective view is not to any particular scale and that the lateral (xy) dimensions and axial (z) thickness can be varied as desired. As shown in  FIG.  22 A , rotational alignment component  2224  has an outer magnetized region  2225  with a magnetic orientation along the axial direction such that the north magnetic pole (N) is nearest the proximal (+z) surface  2203  of rotational alignment component  2224  (as shown by arrows  2205 ) and an inner magnetized region  2227  with a magnetic orientation opposite to the magnetic orientation of the first region such that the south magnetic pole (S) is nearest to proximal surface  2203 . Between magnetized regions  2225  and  2227  is a neutral annular region  2229  that is not magnetized. In some embodiments, rotational alignment component  2224  can be formed from a single piece of magnetic material that is exposed to a magnetizer to create regions  2225 ,  2227 ,  2229 . Alternatively, rotational alignment component  2224  can be formed using two or more pieces of magnetic material with a nonmagnetic material or an air gap between them. As shown in  FIG.  22 B , the proximal surface of rotational alignment component  2224  can have an annular outer region having a “north” polarity and an inner region having a “south” polarity. The proximal surface of a complementary annulus-design rotational alignment component can have an annular outer region of south polarity and an inner region of north polarity. 
       FIGS.  23 A and  23 B  show a perspective view and a top view of a rotational alignment component  2324  having a “triple pole” configuration according to some embodiments. It should be understood that the perspective view is not to any particular scale and that the lateral (xy) dimensions and axial (z) thickness can be varied as desired. As shown in  FIG.  23 A , rotational alignment component  2324  has a central magnetized region  2325  with a magnetic orientation along the axial direction such that the south magnetic pole (S) is nearest the proximal (+z) surface  2303  of rotational alignment component  2324  (as shown by arrow  2305 ) and outer magnetized regions  2327 ,  2329  with a magnetic orientation opposite to the magnetic orientation of central region  2325  such that the north magnetic pole (N) is nearest to proximal surface  2303  (as shown by arrows  2307 ,  2309 ). Between central magnetized region  2325  and each of outer magnetized regions  2327 ,  2329  is a neutral region  2331 ,  2333  that is not strongly magnetized. In some embodiments, rotational alignment component  2324  can be formed from a single piece of magnetic material that is exposed to a magnetizer to create regions  2325 ,  2327 ,  2329 . Alternatively, rotational alignment component  2324  can be formed using three (or more) pieces of magnetic material with nonmagnetic materials or air gaps between them. As shown in  FIG.  23 B , the proximal surface may have a central region having a “south” polarity with an outer region having “north” polarity to either side. The proximal surface of a complementary triple-pole rotational alignment component can have a central region of north polarity with an outer region of south polarity to either side. 
     It should be understood that the examples in  FIGS.  20 A- 23 B  are illustrative and that other configurations may be used. The selection of a magnetization pattern for a rotational alignment component can be independent of the magnetization pattern of an annular alignment component with which the rotational alignment component is used. 
     In some embodiments, the selection of a magnetization pattern for a rotational alignment component can be based on optimizing the torque profile. For example, as noted above, it may be desirable to provide a strong tactile “clocking” sensation to a user when close to the desired rotational alignment. The clocking sensation can be a result of torque about a rotational axis defined by the annular alignment components. The amount of torque depends on various factors, including the distance between the axis and the rotational alignment component (distance y0 in  FIG.  18   ), as well as the strength of the magnetic fields of the rotational alignment components (which may depend on the size of the rotational alignment components) and whether the annular alignment components exert any torque toward a preferred rotational orientation. 
       FIG.  24    shows graphs of torque as a function of angular rotation (in degrees) for an alignment system of the kind shown in  FIG.  18   , for different magnetization configurations of the rotational alignment component according to various embodiments. Angular rotation is defined such that zero degrees corresponds to the target rotational alignment (where the proximal surfaces of rotational angular components  1822  and  1824  are in closest proximity, e.g., as shown in  FIG.  19 B ). Torque is defined such that positive (negative) values indicate force in the direction of decreasing (increasing) rotational angle. For purpose of generating the torque profiles, it is assumed that annular alignment components  1816  and  1818  are rotationally symmetric and do not exert torque about the z axis defined by center points  1801  and  1803 . Three different magnetization configurations are considered. Line  2404  corresponds to the quad-pole configuration of  FIGS.  21 A and  21 B . Line  2405  corresponds to the annulus design configuration of  FIGS.  22 A and  22 B . Line  2406  corresponds to the triple-pole configuration of  FIGS.  23 A and  23 B . As shown, the annulus design (line  2405 ) and triple-pole (line  2406 ) configurations provide a sharper peak in the torque and therefore a more salient clocking sensation for the user, as compared to the quad-pole configuration (line  2404 ). In addition, the triple-pole configuration provides a stronger peak torque and therefore a more salient clocking sensation than the annulus-design configuration. It should be understood that the numerical values in  FIG.  24    are illustrative, and that torque in a particular embodiment may depend on a variety of other factors in addition to the magnetization configuration, such as the magnet volume, aspect ratio, and distance y0 from the center of the annular alignment component. 
     In the examples shown above, a single rotational alignment component is placed outside the annular alignment component at a distance y 0  from the center of the annular alignment component. This arrangement allows a single magnetic element to generate enough torque to produce a salient clocking sensation for a user aligning devices. In some embodiments, other arrangements are also possible. For example,  FIG.  25    shows a portable electronic device  2504  having an alignment system  2500  with multiple rotational alignment components according to some embodiments. In this example, alignment system  2500  includes an annular alignment component  2518  and a set of rotational alignment components  2524  positioned at various locations around the perimeter of annular alignment component  2518 . In this example, there are four rotational alignment components  2524  positioned at angular intervals of approximately 90 degrees. In other embodiments, different numbers and spacing of rotational alignment components can be used. Each rotational alignment component  2524  can have any of the magnetization configurations described above, including z-pole, quad-pole, triple-pole, or annulus-design configurations, or a different configuration. Further, different rotational alignment components  2524  can have different magnetization configurations from each other. It should be noted that rotational alignment components  2524  can be placed close to the perimeter of annular alignment component  2518 , and the larger number of magnetic components can provide increased torque at a smaller radius. Complementary rotation alignment components can be disposed around the outer perimeter of any type of annular alignment component (e.g., primary alignment components, secondary alignment components, or annular alignment components as described herein). 
     It will be appreciated that the foregoing examples of rotational alignment components are illustrative and that variations or modifications are possible. In some embodiments, a rotational alignment component can be provided as an optional adjunct to an annular alignment component, and a device that has both an annular alignment component and a rotational alignment component can align laterally to any other device that has a complementary annular alignment component, regardless of whether the other device has or does not have a rotational alignment component. Thus, for example, portable electronic device  1804  of  FIG.  18    can align rotationally to accessory device  1802  (which has both annular alignment component  1816  and rotational alignment component  1822 ) as well as aligning laterally to another accessory (such as attachable wallet  100  of  FIG.  1   ) that has annular alignment component  1816  but not rotational alignment component  1822 . In the latter case, lateral alignment can be achieved, e.g., to support efficient wireless charging, but there may be no preferred rotational alignment, or rotational alignment may be achieved using a non-magnetic feature (e.g., a mechanical retention feature such as a ledge, a clip, a notch, or the like). A rotational alignment component can be used together with any type of annular alignment component (e.g., primary alignment components, secondary alignment components, or annular alignment components as described herein). 
     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.  26 A through  26 C  illustrate examples of moving magnets according to an embodiment of the present invention. In these examples, first electronic device  2600  can be an attachable wallet, such as attachable wallet  100  shown in  FIG.  1   , a wireless charging device, or other device having a magnet  2610  (which can be, e.g., any of the annular or other magnetic alignment components such as the magnet array  190  and alignment magnets  192  described above). In  FIG.  26 A , moving magnet  2610  can be housed in a first electronic device  2600 . First electronic device  2600  can include device enclosure  2630 , magnet  2610 , and shield  2620 . Magnet  2610  can be in a first position (not shown) adjacent to nonmoving shield  2620 . In this position, magnet  2610  can be separated from device enclosure  2630 . As a result, the magnetic flux  2612  at a surface of device enclosure  2630  can be relatively low, thereby protecting magnetic devices and magnetically stored information, such as information stored on payment cards. As magnet  2610  in first electronic device  2600  is attracted to a second magnet (not shown) in a second electronic device (not shown), magnet  2610  can move, for example it can move away from shield  2620  to be adjacent to device enclosure  2630 , as shown. With magnet  2610  at this location, magnetic flux  2612  at surface of device enclosure  2630  can be relatively high. This increase in magnetic flux  2612  can help to attract the second electronic device to first electronic device  2600 . 
     With this configuration, it can take a large amount of magnetic attraction for magnet  2610  to separate from shield  2620 . 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.  26 B , line  2660  can be used to indicate a split of shield  2620  into a shield  2640  and return plate  2650 . 
     In  FIG.  26 C , moving magnet  2610  can be housed in first electronic device  2600 . First electronic device  2600  can include device enclosure  2630 , magnet  2610 , shield  2640 , and return plate  2650 . In the absence of a magnetic attraction, magnet  2610  can be in a first position (not shown) such that shield  2640  can be adjacent to return plate  2650 . Again, in this configuration, magnetic flux  2612  at a surface of device enclosure  2630  can be relatively low. As magnet  2610  and first electronic device is attracted to a second magnet (not shown) in a second electronic device (not shown), magnet  2610  can move, for example it can move away from return plate  2650  to be adjacent to device enclosure  2630 , as shown. In this configuration, shield  2640  can separate from return plate  2650  and the magnetic flux  2612  at a surface of device enclosure  2630  can be increased. As before, this increase in magnetic flux  2612  can help to attract the second electronic device to the first electronic device  2600 . 
     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.  27 A and  27 B  illustrate a moving magnetic structure according to an embodiment of the present invention. In this example, first electronic device  2700  can be an attachable wallet, such as attachable wallet  100 , a wireless charging device, or other device having a magnet  2710  (which can be, e.g., any of the annular or other magnetic alignment components such as the magnet array  190  and alignment magnets  192  described above).  FIG.  27 A  illustrates a moving first magnet  2710  in a first electronic device  2700 . First electronic device  2700  can include first magnet  2710 , protective surface  2712 , housings  2720  and  2722 , compliant structure  2724 , shield  2740 , and return plate  2750 . In this figure, first magnet  2710  is not attracted to a second magnet (not shown), and therefore shield  2740  is magnetically attracted to or attached to return plate  2750 . In this position, compliant structure  2724  can be expanded or relaxed. Compliant structure  2724  can be formed of an elastomer, silicon rubber open cell foam, silicon rubber, polyurethane foam, or other foam or other compressible material. 
     In  FIG.  27 B , second electronic device  2760  has been brought into proximity of first electronic device  2700 . Second magnet  2770  can attract first magnet  2710 , thereby causing shield  2740  and return plate  2750  to separate from each other. Housings  2720  and  2722  can compress compliant structure  2724 , thereby allowing protective surface  2712  of first electronic device  2700  to move towards or adjacent to housing  2780  of second electronic device  2760 . Second magnet  2770  can be held in place in second electronic device  2760  by housing  2790  or other structure. As second electronic device  2760  is removed from first electronic device  2700 , first magnet  2710  and shield  2740  can be magnetically attracted to return plate  2750 , as shown in  FIG.  27 A . 
       FIGS.  28 A and  28 B  illustrate moving magnetic structures according to an embodiment of the present invention. In this example, first electronic device  2800  can be an attachable wallet, such as attachable wallet  100 , a wireless charging device, or other device having a magnet  2810  (which can be, e.g., any of the annular or other magnetic alignment components such as the magnet array  190  and alignment magnets  192  described above).  FIG.  28 A  illustrates a moving first magnet  2810  in a first electronic device  2800 . First electronic device  2800  can include first magnet  2810 , pliable surface  2812 , housing portions  2820  and  2822 , shield  2840 , and return plate  2850 . In this figure, first magnet  2810  is not attracted to a second magnet, and therefore shield  2840  is magnetically attached or attracted to return plate  2850 . In this position, pliable surface  2812  can be relaxed. Pliable surface  2812  can be formed of an elastomer, silicon rubber open cell foam, silicon rubber, polyurethane foam, or other foam or other compressible material. 
     In  FIG.  28 B , second electronic device  2860  has been brought into the proximity of first electronic device  2800 . Second magnet  2870  can attract first magnet  2810 , thereby causing shield  2840  and return plate  2850  to separate from each other. First magnet  2810  can stretch pliable surface  2812  towards second electronic device  2860 , thereby allowing first magnet  2810  of first electronic device  2800  to move towards housing  2880  of second electronic device  2860 . Second magnet  2870  can be held in place in second electronic device  2860  by housing  2890  or other structure. As second electronic device  2860  is removed from first electronic device  2800 , first magnet  2810  and shield  2840  can be magnetically attracted to return plate  2850  as shown in  FIG.  28 A . 
       FIG.  29    to  FIG.  31    illustrate a moving magnetic structure according to an embodiment of the present invention. In this example, first electronic device  2900  can be an attachable wallet, such as attachable wallet  100 , a wireless charging device, or other device having a magnet  2910  (which can be, e.g., any of the annular or other magnetic alignment components such as the magnet array  190  and alignment magnets  192  described above). In  FIG.  29   , first magnet  2910  and shield  2940  can be magnetically attracted or attached to return plate  2950  in first electronic device  2900 . First electronic device  2900  can be at least partially housed in device enclosure  2920 . In  FIG.  30   , housing  2980  of second electronic device  2960  can move laterally across a surface of device enclosure  2920  of first electronic device  2900  in a direction  2985 . Second magnet  2970  in second electronic device  2960  can begin to attract first magnet  2910  in first electronic device  2900 . This magnetic attraction  2915  can cause first magnet  2910  and shield  2940  to pull away from return plate  2950  by overcoming the magnetic attraction  2945  between shield  2940  and return plate  2950 . In  FIG.  31   , second magnet  2970  in second electronic device  2960  has become aligned with first magnet  2910  in first electronic device  2900 . First magnet  2910  and shield  2940  have pulled away from return plate  2950  thereby reducing the magnetic attraction  2945 . First magnet  2910  has moved nearby or adjacent to device enclosure  2920 , thereby increasing the magnetic attraction  2915  to second magnet  2970  in second electronic device  2960 . 
     As shown in  FIG.  29    through  FIG.  31   , the magnetic attraction between first magnet  2910  in first electronic device  2900  and the second magnet  2970  in the second electronic device  2960  can increase when first magnet  2910  and shield  2940  pull away from return plate  2950 . This is shown graphically in the following figures. 
       FIG.  32    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  FIGS.  29 - 36   , with a large offset between first magnet  2910  and second magnet  3170 , first magnet  2910  and shield  2940  can remain attached to return plate  2950  in first electronic device  2900  and the magnetic attraction  2915  can be minimal. The shear force necessary to overcome this magnetic attraction is illustrated here as curve  3210 . As shown in  FIG.  30   , as the offset or lateral distance between first magnet  2910  and second magnet  2970  decreases, first magnet  2910  and shield  2940  can pull away or separate from return plate  2950 , thereby increasing the magnetic attraction  2915  between first magnet  2910  and second magnet  2970 . This is illustrated here as discontinuity  3220 . As shown in  FIG.  31   , as first magnet  2910  and second magnet  2970  come into alignment, the magnetic attraction  2915  increases along curve  3230  to a maximum  3240 . The difference between curve  3210  and curve  3230  can show the increase in magnetic attraction between a phone or other electronic device, such as second electronic device  2960  and an attachable wallet or wireless charging device, such as first electronic device  2900 , that results from first magnet  2910  being able to move axially. It should also be noted that in this example first magnet  2910  does not move in a lateral direction, though in other examples it is capable of such movement. Where first magnet  2910  is capable of moving in a lateral direction, curve  3230  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  2910 . 
       FIG.  33    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  2910  and second magnet  2970 , there it is no shear force to move second magnet  2970  relative to first magnet  2910 , as shown in  FIG.  29   . As the offset is increased, the shear force, that is the force attempting to realign the magnets, can increase along curve  3340 . At discontinuity  3310 , first magnet  2910  and shield  2940  can return to return plate  2950  (as shown in  FIGS.  29 - 36   ), thereby decreasing the magnetic shear force to point  3320 . The magnetic shear force can continue to drop off along curve  3330  as the offset increases. The difference between curve  3330  and curve  3340  can show the increase in magnetic attraction between a phone or other electronic device, such as second electronic device  2960  and an attachable wallet or wireless charging device, such as first electronic device  2900 , that results from first magnet  2910  being able to move axially. It should also be noted that in this example first magnet  2910  does not move in a lateral direction, though in other examples it is capable of such movement. Where first magnet  2910  is capable of moving in a lateral direction, curve  3330  can remain at zero until the lateral movement of the second magnet  2970  overcomes the range of possible lateral movement of first magnet  2910 . 
     In these and other embodiments of the present invention, it can be desirable to further increase this shear force. Accordingly, embodiments of the present invention can provide various high friction or high stiction surfaces, suction cups, pins, or other structures to increase this shear force. 
     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 a Near-Field Communication 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.  34    shows an exploded view of a wireless charger device  3402  incorporating an NFC tag according to some embodiments, and  FIG.  35    shows a partial cross-section view of wireless charger device  3402  according to some embodiments. As shown in  FIG.  34   , wireless charger device  3402  can include an enclosure  3404 , which can be made of plastic or metal (e.g., aluminum), and a charging surface  3406 , which can be made of silicone, plastic, glass, or other material that is permeable to AC and DC magnetic fields. Charging surface  3406  can be shaped to fit within a circular opening  3403  at the top of enclosure  3404 . 
     A wireless transmitter coil assembly  3411  can be disposed within enclosure  3404 . Wireless transmitter coil assembly  3411  can include a wireless transmitter coil  3412  for inductive power transfer to another device as well as AC magnetic and/or electric shield(s)  3413  disposed around some or all surfaces of wireless transmitter coil  3412 . Control circuitry  3414  (which can include, e.g., a logic board and/or power circuitry) to control wireless transmitter coil  3412  can be disposed in the center of coil  3412  and/or underneath coil  3412 . In some embodiments, control circuitry  3414  can operate wireless transmitter coil  3412  in accordance with a wireless charging protocol such as the Qi protocol or other protocols. 
     A primary annular magnetic alignment component  3416  can surround wireless transmitter coil assembly  3411 . Primary annular magnetic alignment component  3416  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  3416  is chosen such that arcuate magnet sections of primary annular magnetic alignment component  3416  fit under a lip  3409  at the top surface of enclosure  3404 , as best seen in  FIG.  35   . For instance, each arcuate magnet section can be inserted into position under lip  3409 , either before or after magnetizing the inner and outer regions. In some embodiments, primary annular magnetic alignment component  3416  can have a gap  3436  between two adjacent arcuate magnet sections. Gap  3436  can be aligned with an opening  3407  in a side surface of enclosure  3404  to allow external wires to be connected to wireless transmitter coil  3412  and/or control circuitry  3414 . 
     A support ring subassembly  3440  can include an annular frame  3442  that extends in the axial direction and a friction pad  3444  at the top edge of frame  3442 . Friction pad  3444  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  3406 . Frame  3442  can be made of a material such as polycarbonate (PC), glass-fiber reinforced polycarbonate (GFPC), or glass-fiber reinforced polyamide (GFPA). Frame  3442  can have an NFC coil  3464  disposed thereon. For example, NFC coil  3464  can be a four-turn or five-turn solenoidal coil made of copper wire or other conductive wire that is wound onto frame  3442 . In some embodiments, NFC coil  3464  can be electrically connected to NFC tag circuitry (not shown) that can be disposed on frame  3442 . The relevant design principles of NFC circuits are well understood in the art and a detailed description is omitted. Frame  3442  can be inserted into a gap region  3417  between primary annular magnetic alignment component  3416  and wireless transmitter coil assembly  3411 . In some embodiments, gap region  3417  is shielded by AC shield  3413  from AC electromagnetic fields generated in wireless transmitter coil  3412  and is also shielded from DC magnetic fields of primary annular magnetic alignment component  3416  by the closed-loop configuration of the arcuate magnet sections. 
       FIG.  36    illustrates a portion of NFC inlay according to an embodiment of the present invention. NFC inlay  620  can include NFC coil  3710 . NFC coil  3710 , capacitor  3820 , capacitor  3830 , and tag or electronic circuit  3810  can form an NFC circuit or NFC circuitry. NFC coil  3710  can be formed of a wire wrapped in concentric loops. These loops can be positioned in a plane parallel to flexible circuit board  3720 . Alternatively, these loops can be stacked to form a cylindrical surface that is orthogonal to a plane parallel to flexible circuit board  3720 . These loops can be formed by wrapping a wire around a mandrel (not shown) or by using other techniques. The wire can be insulated with insulation (not shown) to prevent the loops from shorting to each other. The wire can further have a layer of adhesive (not shown) on the outside of the insulation. This adhesive can be pressure-sensitive adhesive, heat-activated adhesive, or other type of adhesive. This adhesive can help NFC coil  3710  to maintain shape during manufacturing. 
     The number of loops in NFC coil  3710  can be 5 loops, 7 loops, 9 loops, 11 loops, or other number of loops. The wire forming NFC coil  3710  can have various diameters, such as 50 microns, 100 microns, 150 microns, 200 microns, 300 microns, or other diameter. The wrapped wire forming NFC coil  3710  can include two ends, where a first end  3712  can be positioned on an inside of NFC coil  3710  and a second end  3714  can be positioned on the outside of NFC coil  3710 . First end  3712  of NFC coil  3710  can be attached to flexible circuit board  3720  at encapsulation  3850 . Second end  3714  of NFC coil  3710  can be attached to flexible circuit board  3720  at encapsulation  3840 . Capacitor  3820 , capacitor  3830 , and tag or electronic circuit  3810  can also be attached to flexible circuit board  3720 . Traces  3722  can attach capacitor  3820 , capacitor  3830 , and electronic circuit  3810  to NFC coil  3710 . In this example, two capacitors and one electronic circuit are shown, though in other embodiments of the present invention, other number of capacitors and electronic circuits can be included on flexible circuit board  3720  or elsewhere on or associated with flexible circuit board  3720 . 
       FIG.  37 A  and  FIG.  37 B  illustrate portions of an NFC inlay according to an embodiment of the present invention. In  FIG.  37 A , first end  3712  of NFC coil  3710  can be attached to flexible circuit board  3720  at location  3723 . Second end  3714  of NFC coil  3710  can be attached to flexible circuit board  3720  at location  3724 . Capacitor  3820 , capacitor  3830 , and electronic circuit  3810  can be attached to traces  3722  on flexible circuit board  3720 . 
     In  FIG.  37 B , shim  3730  can be attached to or placed over flexible circuit board  3720  and NFC coil  3710 . Shim  3730  can include opening  3734  for capacitor  3820 , opening  3736  for capacitor  3830 , and opening  3738  for tag or electronic circuit  3810 . Location  3723  and location  3724  (shown in  FIG.  37 A ) can be encapsulated by encapsulation  3840  and encapsulation  3850 . Shim  3730  can include notch  3737  for encapsulation  3840  and notch  3739  for encapsulation  3850 . Again, shim  3730  can provide a planarized surface to help prevent visible or tactile impressions and a surface of back panel  120  (shown in  FIG.  1   ) 
     In these and other embodiments of the present invention, ferrite  610  (shown in  FIG.  3 B ) can be formed in various ways. Similarly, shield layer  460  (shown in  FIG.  4   ) can be formed in various ways. Ferrite  610  and shield layer  460  can be formed of the same or substantially similar layers. Alternatively, ferrite  610  and shield layer  460  can be formed of different layers. Examples are shown in the following figures. 
       FIG.  38    illustrates a cross-section of a ferrite according to an embodiment of the present invention. Ferrite  610  can be formed as a piece of ferritic material. Alternately, ferrite  610  can be formed of a number of layers. In one example, ferrite  610  can be formed of layer  4010 , layer  4020 , layer  4030 , and layer  4040 , where each layer can be the same or substantially similar. For example, layer  4010  can include a top layer of polyester or polyethylene terephthalate (PET) over a layer of ferritic material. An adhesive layer can be attached to a bottom side of the ferritic material such that layer  4010  can adhere to layer  4020 . Layers  4020 , layer  4030 , and layer  4040  can be the same or substantially similar to layer  4010 . In these and other embodiments of the present invention, layer  4050  can be an adhesive layer. When layer  4050  is an adhesive layer, a bottom adhesive layer can be omitted from layer  4040 , though the adhesive layer can be retained to simplify manufacturing. 
     In these and other embodiments of the present invention, it can be desirable for layer  4010 , layer  4020 , layer  4030 , layer  4040  to be cut to shape without breaking the ferritic material into shards. Accordingly, the ferritic material in layer  4010 , layer  4020 , layer  4030 , and layer  4040  can be pre-cracked, for example using rollers or other technique. The adjacent polyester and adhesive layers can help to maintain the form of the ferritic material before and after cracking. 
     In these and other embodiments of the present invention, the ferritic material can be formed of iron, silica and iron, aluminum iron, nanocrystalline structures or other ferritic material, steel, or other material. 
     In these and other embodiments of the present invention, either or both ferrite  610  or shield layer  460  can be formed in other ways. In these and other embodiments of the present invention, a ferrite layer and a metallic layer can be combined to form shield layer  460 . In this way, a ferrite layer having a high permeability can provide magnetic shielding, while the metallic layer can provide magnetic and electric field shielding. An example is shown in the following figure. 
       FIG.  39    illustrates a cross-section of a shield layer according to an embodiment of the present invention. In this example, shield layer  460  can include layer  4110 . Layer  4110  can be formed of polyester or polyethylene terephthalate. This layer can protect a soft magnetic layer or other ferritic layer  4120 . An adhesive layer  4130  and can attach a soft magnetic layer or other ferrite layer  4120  to a metal layer  4140 , which can be formed of copper, steel, or other material. Adhesive layer  4150  can attach shield layer  460  to taffeta layer  480  (shown in  FIG.  4   ), thereby replacing adhesive layer  470  (shown in  FIG.  4   .) In this example, soft magnetic layer or other ferrite layer  4120  can be arranged to face electronic device  200  (shown in  FIG.  1   ), while metal layer  4140  can be arranged to face an outside surface of front panel  110  (shown in  FIG.  1   .) Alternatively, ferrite layer  4120  can be arranged to face an outside surface of front panel  110 , while metal layer  4140  can be arranged to face electronic device  200 . The layers shown as examples for ferrite  610  in  FIG.  38    and shield layer  460  in  FIG.  39    can be implemented in various combinations in each of these structures, and these and other layers can be included or omitted for each of these structures. 
     In these and other embodiments of the present invention, adhesive layers, such as adhesive layer  172 , adhesive layer  174 , adhesive layer  176 , (each shown in  FIG.  3 B ) and the other adhesive layers can be a pressure sensitive adhesive, a double-sided pressure sensitive adhesive, a heat activated adhesive, a double-sided heat activated material, or other type of single or double-sided adhesive layers. 
       FIG.  40    shows a flow diagram of a process  3600  that can be implemented in portable electronic device  5004  according to some embodiments. In some embodiments, process  3600  can be performed iteratively while portable electronic device  5004  is powered on. At block  3602 , process  3600  can determine a baseline magnetic field, e.g., using magnetometer  5080 . At block  3604 , process  3600  can continue to monitor signals from magnetometer  5080  until a change in magnetic field is detected. At block  3606 , process  3600  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  3602 . If, at block  3606 , the change in magnetic field matches a magnitude and direction of change associated with alignment of a complementary alignment component, then at block  3608 , process  3600  can activate the NFC reader circuitry associated with NFC coil  5060  to read an NFC tag of an aligned device. At block  3610 , process  3600  can receive identification information read from the NFC tag. At block  3612 , process  3600  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  3612 , process  3600  can optionally return to block  3602  to provide continuous monitoring of magnetometer  5080 . It should be understood that process  3600  is illustrative and that other processes can be performed in addition to or instead of process  3600 . 
     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: 20210406
Publication Date: 20231212
Grant Date: 20231212
Priority Date: 20200922
Inventors: WULFF, TIMOTHY C.
ZHOU, YANG
WU, James C.
PAN, TAO
ZHANG, Leon Zilun
LUO, Geng
Assignee: APPLE INC
CPC Classifications: [{"code": "A45C11/003", "inventive": false, "first": false, "tree": "[]"}, {"code": "A45C11/002", "inventive": false, "first": false, "tree": "[]"}, {"code": "A45C11/002", "inventive": true, "first": false, "tree": "[]"}, {"code": "A45C11/003", "inventive": true, "first": false, "tree": "[]"}, {"code": "A45C13/1069", "inventive": true, "first": true, "tree": "[]"}, {"code": "A45C11/182", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F7/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "A45C2011/002", "inventive": false, "first": false, "tree": "[]"}, {"code": "A45C2011/003", "inventive": false, "first": false, "tree": "[]"}, {"code": "A45C11/182", "inventive": true, "first": true, "tree": "[]"}, {"code": "A45C13/1069", "inventive": true, "first": true, "tree": "[]"}, {"code": "A45C2011/186", "inventive": false, "first": false, "tree": "[]"}, {"code": "A45C13/1069", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F7/0252", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/361", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01F7/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "A45C11/182", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 80741260