PATENT DOCUMENT

Publication Number: US-10951053-B2
Application Number: US-201816126992-A
Country: US
Kind Code: B2

Title: Portable electronic device

Abstract:
An inductive coil capable of providing power to the battery is described. The inductive coil is formed of a length of a wire having a conductive core capable of carrying an electrical current. The conductive core is surrounded by an insulating layer that electrically isolates the conductive core. Portions of the length of wire include a magnetically permeable material that is plated on an exposed surface of the conductive core.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a battery; and 
 an inductive coil capable of providing power to the battery, the inductive coil comprising:
 a wire having a conductive core capable of carrying an electrical current; 
 an insulating layer that surrounds and electrically isolates the conductive core; 
 a first magnetically permeable material disposed on the conductive core; and 
 a second magnetically permeable material disposed on the conductive core, the second magnetically permeable material electrically isolated from the first magnetically permeable material by the insulating layer. 
 
 
     
     
       2. The electronic device as recited in  claim 1 , further comprising:
 a housing, wherein the battery and the inductive charging coil are disposed in the housing; and 
 a display assembly coupled with the housing. 
 
     
     
       3. The electronic device as recited in  claim 2 , wherein the housing comprises a non-metal portion, and the inductive charging coil is configured to receive an induced current through the non-metal portion. 
     
     
       4. The electronic device as recited in  claim 1 , wherein the first magnetically permeable material limits an eddy current induced in a peripheral region of the conductive core to a first induced eddy current. 
     
     
       5. The electronic device as recited in  claim 4 , wherein the first induced eddy current is less than a second induced eddy current that is capable of being generated in the peripheral region of the conductive core in accordance with an exposed surface of the conductive core, the exposed surface being free of the first magnetically permeable material. 
     
     
       6. The electronic device as recited in  claim 5 , wherein the first induced eddy current corresponds to a first electrical resistance and wherein the second induced eddy current corresponds to a second electrical resistance that is greater than the first electrical resistance. 
     
     
       7. The electronic device as recited in  claim 6 , wherein the first electrical resistance corresponds to a first Q factor that is greater than a second Q factor corresponding to the second electrical resistance. 
     
     
       8. The electronic device as recited in  claim 1 , wherein the first magnetically permeable material comprises a disjoint pattern that is characterized as portions of the plated first magnetically permeable material being isolated from each other. 
     
     
       9. The electronic device as recited in  claim 1 , wherein the first magnetically permeable material has a thickness of about 1-1.5 microns. 
     
     
       10. A portable electronic device, comprising;
 a battery; and 
 an inductive charging unit capable of providing power to the battery, wherein the inductive charging unit comprising:
 an inductive coil that is formed of a wire arranged in a spiral pattern having a first end electrically coupled to a ground and a second end electrically coupled to the battery, wherein the wire includes a conductive core; 
 an insulating layer that electrically isolates the conductive core; and 
 a magnetically permeable material that is plated on the conductive core at an exposed surface of the conductive core, the exposed surface defined by the insulating layer, wherein an interaction with an external magnetic field generates a first eddy current in the conductive core at the insulation layer and a second eddy current in the conductive core at the magnetically permeable material, the second eddy current having a magnitude less than that of the first eddy current. 
 
 
     
     
       11. The portable electronic device as recited in  claim 10 , wherein the magnetically permeable material is capable of limiting an eddy current induced by a magnetic field from an adjacent portion of the wire. 
     
     
       12. The portable electronic device as recited in  claim 10 , wherein the spiral pattern comprises a disjoint pattern that is characterized as portions of the plated magnetically permeable material being isolated from each other. 
     
     
       13. The portable electronic device as recited in  claim 10 , wherein the inductive charging unit has a first Q factor that is greater than a second Q factor corresponding to an absence of the magnetically permeable material. 
     
     
       14. The portable electronic device as recited in  claim 10 , wherein the magnetically permeable material includes a metal. 
     
     
       15. The portable electronic device as recited in  claim 14 , wherein the metal comprises a nickel/iron alloy. 
     
     
       16. A method of forming an inductive charging unit having a wire having a conductive core capable of carrying an electrical current, the method comprising:
 surrounding the conductive core by an insulating layer that electrically isolates the conductive core; 
 exposing at least a portion of an exterior surface of the conductive core, the exterior surfacing defining an exposed portion that lacks the insulating layer; and 
 plating a magnetically permeably material on the exposed portion of the conductive core. 
 
     
     
       17. The method as recited in  claim 16 , wherein the conductive core comprises a disjoint pattern that is characterized as portions of the magnetically permeable material being isolated from each other. 
     
     
       18. The method as recited in  claim 16 , wherein the conductive core comprises a spiral pattern. 
     
     
       19. The method as recited in  claim 16 , wherein the magnetically permeable material includes a metal. 
     
     
       20. The method as recited in  claim 19 , wherein the metal includes any of iron or a nickel/iron alloy.

Description:
FIELD 
     The following description relates to an electronic device. In particular, the following description relates to a portable electronic device (e.g., smartphone) having various features and enhancements. 
     BACKGROUND 
     Portable electronic devices are known to include a housing and a cover glass that combines with the housing to enclose components such as a circuit board, a display, and a battery. Also, portable electronic devices are known to communicate over a network server to send and receive information, as well as communicate with a network carrier to send and receive voice communication. 
     SUMMARY 
     An electronic device includes a battery configured for receiving power from inductive charging and an inductive coil in communication with the battery. The inductive coil is formed of a length of a wire having a conductive core capable of carrying an electrical current. The conductive core is surrounded by an insulating layer that electrically isolates the conductive core and portions of the length of wire include a magnetically permeable material that is plated in a pattern on an exposed surface of the conductive core. 
     A portable electronic device includes a battery and an inductive charging unit coupled to the battery. The inductive charging unit is capable of providing power to the battery and includes an inductive coil that is formed of a wire arranged in a spiral pattern having one end electrically coupled to a ground and a second end electrically coupled to the battery. The wire includes a conductive core capable of carrying an electrical current that is induced by an interaction with an external magnetic field. The conductive core is at least partially surrounded by an insulating layer that electrically isolates the conductive core and portions of the length of wire include a magnetically permeable material that is plated on an exposed surface of the conductive core in a pattern. The magnetically permeable material is capable of limiting an eddy current induced by a magnetic field from an adjacent portion of the wire. 
     A method of forming an inductive charging unit is described. The inductive charging unit has a single length of a wire having a conductive core capable of carrying an electrical current, wherein the conductive core is surrounded by an insulating layer that electrically isolates the conductive core. The method is carried out by exposing at least a portion of an exterior surface of the conductive core and plating a magnetically permeably material on the exposed exterior surface of the conductive core in a pattern. 
     Other systems, methods, features and advantages of the embodiments will be, or will become, apparent to one of ordinary skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description and this summary, be within the scope of the embodiments, and be protected by the following claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which: 
         FIG. 1  illustrates a front isometric view of an embodiment of an electronic device, in accordance with some described embodiments; 
         FIG. 2  illustrates a rear isometric view of the electronic device shown in  FIG. 1 ; 
         FIGS. 3-4  illustrate examples of inductive charging and components used for inductive charging; 
         FIGS. 5A-5B  illustrates portions of inductive coil in accordance with the described embodiments; 
         FIGS. 6A-6B  illustrates portions of inductive coil in accordance with the described embodiments; 
         FIGS. 7A-7C  illustrates portions of inductive coil in accordance with the described embodiments; and 
         FIG. 8  shows a flowchart in accordance with the embodiments. 
     
    
    
     Those skilled in the art will appreciate and understand that, according to common practice, various features of the drawings discussed below are not necessarily drawn to scale, and that dimensions of various features and elements of the drawings may be expanded or reduced to more clearly illustrate the embodiments of the present invention described herein. 
     DETAILED DESCRIPTION 
     Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims. 
     In the following detailed description, references are made to the accompanying drawings, which form a part of the description and in which are shown, by way of illustration, specific embodiments in accordance with the described embodiments. Although these embodiments are described in sufficient detail to enable one skilled in the art to practice the described embodiments, it is understood that these examples are not limiting such that other embodiments may be used, and changes may be made without departing from the spirit and scope of the described embodiments. 
     A changing magnetic field, by electromagnetic induction, can influence the distribution of an electric current flowing within an electrical conductor. For example, when current flows through a conductor, it creates an associated magnetic field around it. The magnetic field induces eddy currents in adjacent conductors, altering the overall distribution of current flowing through them. When, for example, two conductors are nearby each other and carrying current in the same direction, the current in each conductor is concentrated in the areas of the conductor farthest away from the nearby conductor. Referred to as the proximity effect, the redistribution of current flowing within the two conductors can significantly increase the resistance of both conductors. 
     For example, if two portions of a single wire (i.e., carrying the same current) are arranged parallel to one another, as would be found in a coil such that the current in adjacent portions of the coil flows in the same direction, the magnetic field of a first portion of the wire will induce longitudinal eddy currents in a second, adjacent, portion of the wire. In this situation, the eddy currents flow in long loops along the second portion of the wire, in the same direction as the main current on the side of the second portion of the wire facing away from the first portion of the wire, and back in the opposite direction on the side of the second portion of the wire facing the first portion of the wire. In this way, the eddy current reinforces the current on the side of the second portion of the wire facing away from the first portion of the wire and opposes the current on the side facing the first portion of the wire. The net effect is to redistribute the current in the cross section of the second portion of the wire into a thin strip on the side facing away from the first portion of the wire resulting in an increased resistance (the same effect occurs in the first portion of the wire due to the second portion of wire). 
     One way to mitigate the proximity effect is to increase the spacing (or pitch) between adjacent wires (or portions of wires in a loop). However, increasing the spacing between the adjacent portions would reduce the magnetic field provided by the loop resulting in reduced power that can be inductively transferred. Moreover, in the case of a small form factor portable electronic device, the amount of space available to increase the distance between adjacent portions of the wire is quite limited. Accordingly, the following describes a mechanism for mitigating the proximity effect while maintaining a nominal distance between adjacent portions of a wire loop in an inductive coil. The nominal distance can be a value that is consistent with providing an electromagnetic field capable of transferring a desired amount of power between an inductive transmitter and a corresponding inductive receiver. In one embodiment, the inductive receiver (or transmitter) includes a coil having at least a single wire having a first end connected to a power storage unit (such as a battery) and a second end connected to a ground and arranged in a loop. By loop it is meant that the wire, in one embodiment, takes on a spiral like shape (however any suitable shape is possible) such that adjacent portions of the wire carry current in the same direction. In order to mitigate the proximity effect between adjacent portions of the wire, surfaces of the wire include a material capable of mitigating (reducing) the eddy currents formed due to the magnetic field provided by the adjacent portion of the wire. In this way, the reduction of the eddy currents results in a reduction of the current at the surfaces of the wires affected by the eddy currents. More particularly, a cross section of the current flowing within adjacent portions of wire shows a more even distribution than would otherwise be possible. In this way, the overall current distribution is “flattened” out resulting in an overall reduction in resistance to the flow of current in both portions of the wire increasing the overall efficiency (Q factor) of any inductive transfer carried out by the coil. In one embodiment, the surface of the wire can be plated with a ferromagnetic material such as iron (Fe), nickel (Ni), or alloys of iron and nickel, and so forth. 
     The following disclosure relates to an electronic device, such as a mobile communication device that takes the form of a smart phone or a tablet computer device. The electronic device can include several enhancements and modifications not found on traditional electronic devices. For example, the electronic device may include a protective cover (transparent material) and a display assembly coupled to the protective cover, with the display assembly extending to the edges (or at least substantially to the edges) of the protective cover, thereby providing an “edge to edge” appearance of the display assembly as visual information (textual, still images, or motion images, i.e., video) are seen at or near the edges of the protective cover. 
     The electronic device may further include wireless power receiving module designed to receive power by magnetic induction and use the power to provide energy directly to charge the battery assembly. The wireless power receiving module may include a receiver coil such that, when exposed to magnetic flux from an alternating electromagnetic field, received an induced (alternating) current that can be converted to a direct current. The wireless power receiving module may provide a simplified by method for charging the battery, whereby exposure to the magnetic flux, rather than plugging a connector (of a cable assembly) into the electronic device, is sufficient to charge the battery assembly. 
     These and other embodiments are discussed below with reference to  FIGS. 1-6 . However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these Figures is for explanatory purposes only and should not be construed as limiting. 
       FIG. 1  illustrates a front isometric view of an embodiment of an electronic device  100 , in accordance with some described embodiments. In some embodiments, the electronic device  100  is a tablet computer device. In the embodiment shown in  FIG. 1 , the electronic device  100  is a mobile wireless communication device (a smartphone, for example). The electronic device  100  may include a band  102  that extends defines an outer perimeter of the electronic device  100 . The band  102  may include a metal, such as aluminum, stainless steel, or an alloy that includes at least one of aluminum or stainless steel. The band  102  may be composed of several sidewall components, such as a first sidewall component  104 , a second sidewall component  106 , a third sidewall component  108  (opposite the first sidewall component  104 ), and a fourth sidewall component (not shown in  FIG. 1 ). The aforementioned sidewall components may include any material(s) previously described for the band  102 . 
     In some instances, some of the sidewall components form part of an antenna assembly (not shown in  FIG. 1 ). As a result, a non-metal material, or materials, may separate the sidewall components of the band  102  from each other in order to electrically isolate the sidewall components. For example, a first composite material  106  separates the first sidewall component  104  from the second sidewall component  106 , and a second composite material  108  separates the second sidewall component  106  from the third sidewall component  108 . The aforementioned composite may include an electrically inert, or insulating, material(s), such as plastics and/or resin, as non-limiting examples. 
     The electronic device  100  may further include a display assembly  116  (shown as a dotted line) that is covered by a protective cover  118 . The display assembly  116  may include multiple layers (discussed below), with each layer providing a unique function. The display assembly  116  may be partially covered by a border  120 , or frame, that extends along an outer edge of the protective cover  118  and partially covers an outer edge of the display assembly  116 . The border  120  can be positioned to hide or obscure any electrical and mechanical connections between the layers of the display assembly  116  and flexible circuit connectors. This will be shown below. Also, the border  120  may include uniform thickness. For example, the border  120  may include a thickness that generally does not change in the X- and Y-dimensions. 
     Also, as shown in  FIG. 1 , the display assembly  116  may include a notch  122 , representing an absence of the display assembly  116 . The notch  122  may allow for a vision system (discussed below) that provides the electronic device  100  with information for object recognition, such as facial recognition. In this regard, the electronic device  100  may include a masking layer with openings (shown as dotted lines) designed to hide or obscure the vision system, while the openings allow the vision system provide the object recognition information. This will be further discussed below. Also, the protective cover  118  may be formed from a transparent material, such as glass, plastic, sapphire, or the like. In this regard, the protective cover  118  may be referred to as a transparent cover, a transparent protective cover, or a cover glass (when the protective cover  118  includes glass). As shown in  FIG. 1 , the protective cover  118  includes an opening  124 , which may represent a single opening of the protective cover  118 . The opening  124  may allow for transmission of acoustical energy (in the form of audible sound) into the electronic device  100 , which may be received by a microphone (not shown in  FIG. 1 ) of the electronic device  100 . Further, the opening  124  may allow for transmission of acoustical energy (in the form of audible sound) out the electronic device  100 , which may be generated by an audio module (not shown in  FIG. 1 ) of the electronic device  100 . Also, the electronic device  100  may not include a button, such as “home button,” commonly found in electronic devices, as the protective cover  118  does not include additional openings. 
     The electronic device  100  may further include a port  126  designed to receive a connector of a cable assembly. The port  126  allows the electronic device  100  to communication data information (send and receive), and also allows the electronic device  100  to receive electrical energy to charge a battery assembly (not shown in  FIG. 1 ). Accordingly, the port  126  may include terminals (not shown in  FIG. 1 ) that electrically couple to the connector. 
     Also, the electronic device  100  may include several openings. For example, the electronic device  100  may include openings  128  that allow an additional audio module (not shown in  FIG. 1 ) of the electronic device to emit acoustical energy out of the electronic device  100 . The electronic device  100  may further include openings  132  that allow an additional microphone (not shown in  FIG. 1 ) of the electronic device to receive acoustical energy. Also, the electronic device  100  may include a first fastener  134  and a second fastener  136  designed to secure with a rail (not shown in  FIG. 1 ) that is coupled to the protective cover  118 . In this regard, the first fastener  134  and the second fastener  136  are designed to couple the protective cover  118  with the band  102 . 
     The electronic device  100  may include several control inputs designed to provide a command to the electronic device  100 . For example, the electronic device  100  may include a first control input  142  and a second control input  144 . The aforementioned control inputs may be used to adjust the visual information presented on the display assembly  116  or the volume of acoustical energy output by an audio module, as non-limiting examples. The controls may include one of a switch or a button designed to generate a command to a processor circuit (not shown in  FIG. 1 ). The control inputs may at least partially extend through openings in the sidewall components. For example, the second sidewall component  106  may include an opening  146  that receives the first control input  142 . 
       FIG. 2  illustrates a rear isometric view of the electronic device  100  shown in  FIG. 1 . In addition to the aforementioned sidewall components, the band  102  may further include a fourth sidewall component  110 . As shown, a third composite material  152  separates the first sidewall component  104  from the fourth sidewall component  110 , and a fourth composite material  154  separates the fourth sidewall component  110  from the third sidewall component  108 . 
     The electronic device  100  may further include a protective cover  158  that couples with the band  102 . In this regard, the protective cover  158  may combine with the band  102  to form an enclosure of the electronic device  100 , with the enclosure (band  102  and protective cover  158 ) defining an internal volume that carries several internal components, such as a battery assembly, circuit board assembly, vision system, as non-limiting examples. The protective cover  158  may include any material(s) previously described for the protective cover  108  (shown in  FIG. 1 ). When the protective cover  158  include a non-metal material, the electronic device  100  may provide hardware (and software) to support wireless charging. For example, the electronic device  100  may include a wireless power receiving module  30  (represented by a dotted line) covered by the protective cover  158 . The wireless power receiving module  30  is designed to receive an induced current when exposed to an alternating electromagnetic field. This will be further discussed below. Also, the protective cover  118  (shown in  FIG. 1 ) may be referred to as a “front protective cover” and the protective cover  158  may be referred to as a “rear protective cover,” as the front of the electronic device  100  is generally associated with the display assembly  116  (which is covered by the protective cover  118 ), and the back of the electronic device  100  is generally associated with a rear wall, such as the protective cover  158 . 
     The electronic device  100  may further include a camera assembly  170 , which may include a dual camera assembly. As shown, the camera assembly  170  may include a first camera module  172 , a second camera module  174 , and a light emitter  176  positioned between the first camera module  172  and the second camera module  174 . The light emitter  176  is designed to provide additional lighting during an image capture event by the first camera module  172  and/or the second camera module  174 . However, it is desired to isolate some of the light “leakage” from the light emitter into the first camera module  172  and the second camera module  174 . In this regard, the camera assembly  170  may further include a trim element (not shown in  FIG. 1 ) designed to optically isolate the light emitter  176  from the first camera module  172  and the second camera module  174 . In this manner, the first camera module  172  and the second camera module  174  may only receive desired light from the light emitter  176 , such as light reflected from an object, the image of which is the first camera module  172  and/or the second camera module  174 ). The trim element will be further shown and described below. Also, the camera assembly  170  may further include a protective cover  178  formed from a transparent material that covers the first camera module  172 , the second camera module  174 , and the light emitter  176 . However, the protective cover  178  may include a masking layer (not shown in  FIG. 2 ) designed to at least partially obscure part of protective cover the first camera module  172 , the second camera module  174 , and the light emitter  176 . It should be noted, however, that the masking layer includes openings that allow the first camera module  172  and the second camera module  174  to capture images, and that allow the light emitter  176  to emit light that exits the electronic device  100 . Also, as shown in  FIG. 2 , the first camera module  172  and the second camera module  174  are aligned (collectively) in a manner that is parallel with respect to the second sidewall component  106  (shown in  FIG. 1 ) and the fourth sidewall component  110 . In other words, an imaginary line can be drawn through the first camera module  172  and the second camera module  174  that is parallel with respect the second sidewall component  106  (shown in  FIG. 1 ) and the fourth sidewall component  110 . Moreover, the electronic device  100  may further include a wireless power receiving module  160  designed to provide electrical energy to a battery assembly. The wireless power receiving module  160  may include a receiver coil (not shown) designed to receive an induced current by an alternating electromagnetic field generated by a transmitter coil (not shown) that is external with respect to the electronic device  100 . 
       FIG. 3  is a simplified diagram illustrating an exemplary wireless charging system  300  including a transmitter shield  302  and a receiver shield  304 , in accordance with some described embodiments. The transmitter shield  302  may be positioned in front of a transmitter coil  306  so that magnetic flux  310  is directed toward the transmitter shield  302 . For instance, the transmitter shield  302  is positioned between a transmitter coil  306  and a receiver coil  308  during wireless power transfer so that the magnetic flux  310  first passes through the transmitter shield  302  before reaching the receiver coil  308 . In some embodiments, the transmitter shield  302  can be positioned between an interface  316  and transmitter coil  306  when an electronic device (such as the electronic device  100 , shown in  FIGS. 1 and 2 ) rests on a wireless charging device to perform wireless power transfer to the electronic device. Accordingly, the transmitter shield  302  and the transmitter coil  306  can both be positioned within the wireless charging device. The transmitter shield  302  can be substantially transparent to the magnetic flux  310  so that the receiver coil  308  receives a substantial percentage of the magnetic flux  310  generated by the transmitter coil  306 . 
     While the transmitter shield  302  can be substantially transparent to the magnetic flux  310 , the transmitter shield  302  can, on the other hand, be substantially opaque to an electric field  318  such that the transmitter shield  302  substantially blocks the electric field. This prevents electric field  318  from exposing on the receiver coil  308  and generating a detrimental voltage on the receiver coil  308 . Due in part to the transmitter shield  302  substantially blocking the electric field  318  before the electric field  318  can reach the receiver coil  308 , the electric field  318  may generate voltage on the transmitter shield  302  instead of the receiver coil  308 . The amount of voltage generated on the transmitter shield  302  may correspond to the amount of voltage that would have been generated on the transmitter coil  308  had the transmitter shield  302  not been present. 
     In some embodiments, voltage generated on the transmitter shield  302  can be removed so that the voltage does not permanently remain on the transmitter shield  302 . As an example, voltage on the transmitter shield  302  can be discharged to ground. Thus, transmitter shield  302  can be coupled to a ground connection  322  to allow voltage on the transmitter shield  302  to be discharged to ground. The ground connection  322  can be a ground ring or any other suitable conductive structure coupled to ground that can remove voltage from the transmitter shield  302 . 
     Similar to the transmitter shield  302 , the receiver shield  304  may also be implemented in the wireless charging system  300  to prevent detrimental voltage from being generated on the transmitter coil  306  from an electric field  324  generated by the receiver coil  308 . The receiver shield  304  may be positioned in front of the receiver coil  308  so that the magnetic flux  310  first passes through the receiver shield  304  before reaching the receiver coil  308 . In some embodiments, the receiver shield  304  and the receiver coil  308  are positioned within a wireless power receiving module, which in turn is positioned within a housing of an electronic device (such as the electronic device  100 , shown in  FIGS. 1 and 2 ). Within the module, the receiver shield  304  can be positioned between the interface  316  and the receiver coil  308  when the electronic device rests on a wireless charging device to perform wireless power transfer. 
     Similar to the transmitter shield  302 , the receiver shield  304  can be substantially transparent to the magnetic flux  310  so that a substantial percentage of the magnetic flux  310  generated by the transmitter coil  306  passes through the receiver shield  304  and is received by the receiver coil  308 , while the receiver shield  304  can be substantially opaque to the electric field  324  such that the receiver shield  304  substantially blocks the electric field  324 . This prevents the electric field  324  from reaching the transmitter coil  306  and generating a detrimental voltage on the transmitter coil  306  while enabling wireless power transfer. Like the transmitter shield  302 , the receiver shield  304  may also be grounded so that voltage generated by the electric field  324  may be discharged to a ground connection  326 . The ground connection  326  may be a structure similar to the ground connection  322  in some embodiments, or it may be the same structure as the ground connection  322  in other embodiments. 
     By incorporating the transmitter shield  302  and the receiver shield  304  into the wireless charging system  300 , the wireless charging device and the electronic device within which the transmitter shield  302  and the receiver shield  304  are implemented, respectively, are exposing their grounds to each other. This mutes any ground noise caused by the electrical interactions between the transmitter coil  306  and the receiver coil  308 . As can be appreciated by disclosures herein, the transmitter shield  302  and the receiver shield  304  are shielding structures that are able to block the passage of electric fields, yet allow the passage of magnetic flux. Also, in some embodiments, a transmitter shield can be included in a wireless charging device, such as a wireless charging mat, and a receiver shield can be included within a wireless power receiving module included within a portable electronic device configured to rest on the wireless charging device to wirelessly receiver power from the wireless charging mat. 
       FIG. 4  illustrates an exploded view of a wireless power receiving module  400  that can be incorporated into an electronic device  450  to receive power by magnetic induction, in accordance with some described embodiments. The wireless power receiving module  400  may be incorporated with the electronic device  450  in order to receive, and subsequently provide, electrical energy to a battery assembly. Also, the wireless power receiving module  400  may be positioned in the opening  452  of the chassis  454 . Accordingly, the opening  452  may include a size and shape to receive the wireless power receiving module  400 . Also, the wireless power receiving module  400  can include several separate shields. For example, the wireless power receiving module  400  may include an integrated coil  402 , a ferrite shield  404 , and a thermal shield  406  along with an adhesive component  408  that attaches the wireless power receiving module  400  to the protective cover  458 . Although not shown, an additional non-metal structural element may be positioned between the protective cover  458  and the wireless power receiving module  400 . 
     The integrated coil  402  can act as, for example, a receiver coil and a receiver shield. In this manner, integrated coil  402  may enable the wireless power receiving module  400  to wirelessly receive power transmitted from a wireless power transmitting coil. When positioned within the electronic device  450 , integrated coil  402  may be positioned near the charging surface of the electronic device (which may be defined in part by the protective cover  458 ). Thus, the receiver shield is positioned between the receiver coil and the transmitter coil and serves to prevent capacitive coupling to the transmitter coil in a wireless charging device use to induce a current to the wireless power receiving module  400 . The ferrite shield  404  acts as a magnetic field, or B-field, shield redirecting magnetic flux to get higher coupling to the transmitter coil resulting in improved charging efficiency and helping prevent magnetic flux interference. The thermal shield  406  can include a graphite or similar layer that provides thermal isolation between wireless power receiving module  400  and the battery and other components of the electronic device in which the wireless power receiving module  400  is incorporated. The thermal shield  406  can also include a copper layer that is tied to an electrical ground and contributes to the thermal shielding while also capturing stray flux 
     In inductive charging systems, the electronic device is in inductive communication with a charging pad and is receiving signal from the charging pad. However, due to the amount of interference that can be generated during the inductive charging, the features of the phone display (e.g., touch display, applications, web browsing, etc.) are not available as their functions are disrupted by the inductive charging signal. Therefore, shielding to prevent the inductive signals from interfering with the display functionality while also maintaining inductive charging capabilities are desired. 
     A changing magnetic field, by electromagnetic induction, can influence the distribution of an electric current flowing within an electrical conductor. For example, when current flows through a conductor, it creates an associated magnetic field around it. The magnetic field induces eddy currents in adjacent conductors, altering the overall distribution of current flowing through them. When, for example, two conductors are nearby each other and carrying current in the same direction, the current in each conductor is concentrated in the areas of the conductor farthest away from the nearby conductor. Referred to as the proximity effect, the redistribution of current flowing within the two conductors can significantly increase the resistance of both conductors. 
     For example, if two portions of a single wire (i.e., carrying the same current) are arranged parallel to one another, as would be found in a coil such that the current in adjacent portions of the coil flows in the same direction, the magnetic field of a first portion of the wire will induce longitudinal eddy currents in a second, adjacent, portion of the wire. In this situation, the eddy currents flow in long loops along the second portion of the wire, in the same direction as the main current on the side of the second portion of the wire facing away from the first portion of the wire, and back in the opposite direction on the side of the second portion of the wire facing the first portion of the wire. In this way, the eddy current reinforces the current on the side of the second portion of the wire facing away from the first portion of the wire and opposes the current on the side facing the first portion of the wire. The net effect is to redistribute the current in the cross section of the second portion of the wire into a thin strip on the side facing away from the first portion of the wire resulting in an increased resistance (the same effect occurs in the first portion of the wire due to the second portion of wire). 
     In order to mitigate the proximity effect between adjacent portions of the wire, surfaces of the wire include a material capable of mitigating (reducing) the eddy currents formed due to the magnetic field provided by the adjacent portion of the wire. In this way, the reduction of the eddy currents results in a reduction of the current at the surfaces of the wires affected by the eddy currents. In one embodiment, the material can be plated on an exposed surface of a core conductor in a pattern. 
     In one embodiment, the pattern can be a disjoint pattern by which it is meant that portions of the plated magnetically permeable material can be electrically isolated from each other. In another embodiment, the pattern can take on a spiral shape that wraps around an exposed surface of the conductive core. In one embodiment, the spiral shaped pattern can be disjoint in that the spiral shaped pattern includes electrically disjoint regions. In this way, induced magnetic loops are limited to individual regions thereby limiting the effects on the current density in conductive core. 
     For example,  FIG. 5A  shows representative cross section  500  of conductive core  502  surrounded by insulating layer  504  at surface  506  and that lacks plated magnetically permeable material.  FIG. 5B  shows corresponding current density profile  512  that exhibits current spikes  514  within annular region  510  of conductive core  502 . Current density profile distribution  512  can be characterized as having current density difference Δ 1  between current spike  514  and minimum current  516  corresponding to an increase in overall resistance to a current flow in conductor core  502 . However,  FIG. 6A  illustrates an embodiment whereby layer  518  of magnetically permeable material is plated on an exposed portion of surface  506  The presence of magnetically permeable material  518  can mitigate the formation of eddy currents caused by the presence of a magnetic field induced by a current flow in an adjacent conductive core (not shown). Accordingly, as shown in  FIG. 6B , layer  518  can reduce eddy currents created in annular region  510  thereby reducing current spikes  522  in corresponding current density distribution within annular region  510  resulting in “smoother” current density profile  524  having a corresponding current density difference Δ 2  less than current density difference Δ 1 . In this way, the overall resistance to a current flow in conductive core  502  is commensurably reduced. 
     It should be noted that in one embodiment, layer  516  can be plated in a disjoint pattern by which it is meant that plated layer  516  can be formed of individual segments (see  FIG. 5B ) each of which are electrically isolated from each other (i.e., disjoint). In this way, the inducing magnetic flux loop can be reduced to smaller magnetic loops reducing the overall effect on the current distribution in annular region  510 . In another embodiment, plated layer  516  can take on a more continuous pattern, such as a spiral. In any case, the effect of plated layer  516  is to reduce the current density in annular region  510 . It should be noted that a thickness of plated layer  516  can generally in the range of about 1-1.5 microns. In any case, the thickness is less than that of the insulating layers such that the distance between adjacent conductive cores is not increased. In this way, the overall current distribution is “flattened” out resulting in an overall reduction in resistance to the flow of current in both portions of the wire increasing the overall efficiency (Q factor) of any inductive transfer carried out by the coil. In one embodiment, the surface of the wire can be plated with a ferromagnetic material such as iron (Fe), nickel (Ni), or alloys of iron and nickel, and so forth. 
     More specifically,  FIG. 7A  shows configuration  700  showing regions of layer  518  of plated magnetically permeable arranged in a disjoint pattern. In this arrangement, the regions are separate from each other by insulating layer  504  and are therefore electrically isolated from each other.  FIG. 7B  shows another disjoint pattern whereby the regions of layer  518  are separated from each other by insulating layer  504  in a striped pattern.  FIG. 7C  shows a non-disjoint pattern whereby a single layer  518  of magnetically permeable material forms a spiral pattern. 
       FIG. 8  shows a flowchart detailing process  800  in accordance with the described embodiments. More particularly, process  800  can be carried out by, at  802 , exposing at least a portion of an exterior surface of the conductive core, and, at  804 , plating a magnetically permeably material on the exposed exterior surface of the conductive core in a pattern. 
     The various aspects, embodiments, implementations or features of the described embodiments can be used separately or in any combination. Various aspects of the described embodiments can be implemented by software, hardware or a combination of hardware and software. The described embodiments can also be embodied as computer readable code on a computer readable medium for controlling manufacturing operations or as computer readable code on a computer readable medium for controlling a manufacturing line. The computer readable medium is any data storage device that can store data which can thereafter be read by a computer system. Examples of the computer readable medium include read-only memory, random-access memory, CD-ROMs, HDDs, DVDs, magnetic tape, and optical data storage devices. The computer readable medium can also be distributed over network-coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not targeted to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.

Metadata:
Filing Date: 20180910
Publication Date: 20210316
Grant Date: 20210316
Priority Date: 20180910
Inventors: GRAHAM, Christopher S.
LARSSON, KARL RUBEN F.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01F27/361", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/361", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/346", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F2027/348", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01F27/2823", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01F38/14", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J50/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F2027/348", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01F27/36", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F2027/348", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01F27/346", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/025", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 69720153