PATENT DOCUMENT

Publication Number: US-10084349-B2
Application Number: US-201715701237-A
Country: US
Kind Code: B2

Title: Inductive module

Abstract:
Embodiments describe a wireless power receiving module to receive magnetic flux for wireless power transfer. The wireless power receiving module includes a receiver coil comprising a single length of wire wound into a plurality of turns, an electromagnetic receiver shield coupled to a first side of the receiver coil, a ferrite layer coupled to a second side of the receiver coil opposite of the first side, the ferrite layer positioned to redirect magnetic flux during the charging event to improve charging efficiency, and a thermal mitigation shield comprising a thermally conductive layer adhered to an electrically conductive layer where the electrically conductive layer is coupled to ground, and where the ferrite layer is sandwiched between the thermal mitigation shield and the receiver coil.

Claims:
What is claimed is: 
     
       1. A wireless power receiving module to receive magnetic flux for wireless power transfer, the module comprising:
 a receiver coil comprising a single length of wire wound into a plurality of turns, the receiver coil configured to receive magnetic flux generated by a transmitter coil in a wireless charging device during a charging event and generate a plurality of electric fields; 
 an electromagnetic receiver shield that is a passive component and coupled to a first side of the receiver coil, the electromagnetic receiver shield being configured to intercept some of the plurality of electric fields directed away from the receiver coil and allow the magnetic flux to pass through the first electromagnetic receiver shield toward the receiver coil; 
 a ferrite layer coupled to a second side of the receiver coil opposite of the first side, the ferrite layer positioned to redirect magnetic flux during the charging event to improve charging efficiency; and 
 a thermal mitigation shield comprising a thermally conductive layer adhered to an electrically conductive layer where the electrically conductive layer is coupled to ground, enabling the electrically conductive layer to capture stray flux during the charging event, wherein the ferrite layer is sandwiched between the thermal mitigation shield and the receiver coil. 
 
     
     
       2. The wireless power receiving module of  claim 1 , wherein the electromagnetic receiver shield is grounded to discharge voltage generated by the plurality of electric fields. 
     
     
       3. The wireless power receiving module of  claim 1 , wherein the electromagnetic receiver shield comprises silver. 
     
     
       4. The wireless power receiving module of  claim 1 , wherein the receiver coil comprises copper wire having plated layers of nickel and immersion gold formed over the copper wire. 
     
     
       5. The wireless power receiving module of  claim 1 , wherein the thermally conductive layer comprises graphite and the electrically conductive layer comprises copper. 
     
     
       6. The wireless power receiving module of  claim 1 , further comprising a flex circuit formed of a flexible dielectric layer having first and second opposing sides, wherein the receiver coil is disposed on the first side and the electromagnetic receiver shield is disposed on the second side. 
     
     
       7. The wireless power receiving module of  claim 1 , wherein the receiver coil is directly attached to the ferrite layer. 
     
     
       8. The wireless power receiving module of  claim 1 , wherein the receiver coil has a trace width-to-gap ratio of 70 to 30. 
     
     
       9. The wireless power receiving module of  claim 1 , wherein each turn of the plurality of turns have a wire width that is different than other turns of the plurality of turns. 
     
     
       10. An electronic device configured to receive magnetic flux for wireless power transfer, the electronic device comprising:
 a housing having a charging surface; 
 a battery positioned within the housing; 
 a wireless power receiving module positioned within the housing adjacent to the charging surface to receive magnetic flux for wireless power transfer during a charging event, the wireless power receiving module comprising:
 a receiver coil comprising a single length of wire wound into a plurality of turns, the receiver coil configured to receive magnetic flux generated by a transmitter coil in a wireless charging device during a charging event and generate a plurality of electric fields; 
 an electromagnetic receiver shield that is a passive component and coupled to a first side of the receiver coil, the electromagnetic receiver shield being configured to intercept some of the plurality of electric fields directed away from the receiver coil and allow the magnetic flux to pass through the first electromagnetic receiver shield toward the receiver coil; 
 a ferrite layer coupled to a second side of the receiver coil opposite of the first side, the ferrite layer positioned to redirect magnetic flux during the charging event to improve charging efficiency; and 
 a thermal mitigation shield comprising a thermally conductive layer adhered to an electrically conductive layer where the electrically conductive layer is coupled to ground, enabling the electrically conductive layer to capture stray flux during the charging event, wherein the ferrite layer is sandwiched between the thermal mitigation shield and the receiver coil. 
 
 
     
     
       11. The electronic device of  claim 10 , wherein the electromagnetic receiver shield is grounded to discharge voltage generated by the plurality of electric fields. 
     
     
       12. The electronic device of  claim 10 , wherein the electromagnetic receiver shield comprises silver. 
     
     
       13. The electronic device of  claim 10 , wherein the receiver coil comprises copper wire having plated layers of nickel and immersion gold formed over the copper wire. 
     
     
       14. The electronic device of  claim 10 , wherein the thermally conductive layer comprises graphite and the electrically conductive layer comprises copper. 
     
     
       15. A wireless charging system comprising:
 a wireless charging device including a transmitter coil configured to generate a magnetic flux across a charging surface and a transmitter shield positioned between the charging surface and the transmitter coil, the transmitter shield made from material that enables the transmitter shield to intercept some electric fields generated during a charging event and directed away from the transmitter coil and allow the magnetic flux to pass through the transmitter shield; 
 an electronic device configured to receive the magnetic flux generated by the wireless charging device during a charging event, the electronic device comprising: a housing having a charging surface; a battery positioned within the housing; and a wireless power receiving module positioned within the housing adjacent to the charging surface to receive magnetic flux for wireless power transfer during a charging event, the wireless power receiving module comprising:
 a receiver coil comprising a single length of wire wound into a plurality of turns, the receiver coil configured to receive magnetic flux generated by a transmitter coil in a wireless charging device during a charging event and generate a plurality of electric fields; 
 an electromagnetic receiver shield that is a passive component and coupled to a first side of the receiver coil, the electromagnetic receiver shield being configured to intercept some of the plurality of electric fields directed away from the receiver coil and allow the magnetic flux to pass through the first electromagnetic receiver shield toward the receiver coil; 
 a ferrite layer coupled to a second side of the receiver coil opposite of the first side, the ferrite layer positioned to redirect magnetic flux during the charging event to improve charging efficiency; and 
 a thermal mitigation shield comprising a thermally conductive layer adhered to an electrically conductive layer where the electrically conductive layer is coupled to ground, enabling the electrically conductive layer to capture stray flux during the charging event, wherein the ferrite layer is sandwiched between the thermal mitigation shield and the receiver coil. 
 
 
     
     
       16. The wireless charging system of  claim 15 , wherein the electromagnetic receiver shield is grounded to discharge voltage generated by the plurality of electric fields. 
     
     
       17. The wireless charging system of  claim 15 , wherein the electromagnetic receiver shield comprises silver. 
     
     
       18. The wireless charging system of  claim 15 , wherein the receiver coil comprises copper wire having plated layers of nickel and immersion gold formed over the copper wire. 
     
     
       19. The wireless charging system of  claim 15 , wherein the thermally conductive layer comprises graphite and the electrically conductive layer comprises copper. 
     
     
       20. The wireless charging system of  claim 15 , further comprising a flex circuit formed of a flexible dielectric layer having first and second opposing sides, wherein the receiver coil is disposed on the first side and the electromagnetic receiver shield is disposed on the second side.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a non-provisional patent application of and claims the benefit to U.S. Provisional Patent Application No. 62/459,149, filed Feb. 15, 2017 and titled “Inductive Module,” and U.S. Provisional Patent Application No. 62/542,206, filed Aug. 7, 2017 titled “Inductive Module,” and is related to concurrently filed and commonly assigned U.S. patent application Ser. No. 15/701,224, entitled “ELECTROMAGNETIC SHIELDING FOR WIRELESS POWER TRANSFER SYSTEMS”, the disclosures of which are herein incorporated by reference in their entirety for all purposes. 
    
    
     BACKGROUND 
     Portable electronic devices (e.g., mobile phones, media players, electronic watches, and the like) include a rechargeable battery that provides electrical power to operate the devices. In many such devices the battery can be recharged by coupling the electronic device to a power source through a physical connection, such as through a charging cord. Using a charging cord to charge a battery in an electronic device, however, requires the electronic device to be physically tethered to a power outlet. Additionally, using a charging cord requires the mobile device to have a connector, typically a receptacle connector, configured to mate with a connector, typically a plug connector, of the charging cord. The receptacle connector typically includes a cavity in the electronic device that provides an avenue within which dust and moisture can intrude and damage the device. Furthermore, a user of the electronic device has to physically connect the charging cable to the receptacle connector in order to charge the battery. 
     To avoid such shortcomings, wireless charging devices have been developed to wirelessly charge electronic devices without the need for a charging cord. For example, the battery in some electronic devices can be recharged by merely resting the device on a charging surface of a wireless charging device. A transmitter coil disposed below the charging surface may produce a time-varying magnetic flux that induces a current in a corresponding receiving coil in the electronic device. The induced current can be used by the electronic device to charge its internal battery. 
     Some existing wireless charging devices and electronic devices configured for wireless charging have a number of disadvantages. For instance, some wireless charging devices generate an unintended voltage on a receiving coil. The unintended voltage can create noise in the electronic device within which the receiving coil is housed. The noise can cause disturbance of sensitive electronic components in the electronic device, such as touch-sensitive components like a touch-sensitive display. As another example, while being charged, some electronic devices generate an unintended voltage on a transmitter coil in the wireless charging device. The unintended voltage can cause inefficiencies in the wireless power transfer. Additionally, the receiver coil and other components that are required for an electronic device to wirelessly receive power from a wireless charging device require a certain amount of real estate in the electronic device and can undesirably increase a thickness of the electronic device as compared to a similar device without a receiver coil and its associated components. 
     BRIEF SUMMARY 
     Some embodiments of the disclosure pertain to a wireless charging system with shielding components that avoid the generation of detrimental voltages on a receiver coil and/or a transmitter coil of the charging system during wireless power transfer. In some embodiments, a transmitter shield and a receiver shield are implemented in a wireless charging system to intercept electric fields generated between the transmitter coil and the receiver coil during wireless power transfer. By intercepting the electric fields, detrimental voltages are prevented from being generated on the receiver coil by the transmitter coil, and vice versa, during wireless power transfer. 
     In some embodiments, a wireless power receiving module to receive magnetic flux for wireless power transfer includes a receiver coil comprising a single length of wire wound into a plurality of turns, the receiver coil configured to receive magnetic flux generated by a transmitter coil in a wireless charging device during a charging event and generate a plurality of electric fields; an electromagnetic receiver shield coupled to a first side of the receiver coil, the electromagnetic receiver shield being configured to intercept some of the plurality of electric fields directed away from the receiver coil and allow the magnetic flux to pass through the first electromagnetic receiver shield toward the receiver coil; a ferrite layer coupled to a second side of the receiver coil opposite of the first side, the ferrite layer positioned to redirect magnetic flux during the charging event to improve charging efficiency; and a thermal mitigation shield comprising a thermally conductive layer adhered to an electrically conductive layer where the electrically conductive layer is coupled to ground, enabling the electrically conductive layer to capture stray flux during the charging event, where the ferrite layer is sandwiched between the thermal mitigation shield and the receiver coil. 
     The electromagnetic receiver shield can be grounded to discharge voltage generated by the plurality of electric fields. In particular embodiments, the electromagnetic receiver shield includes silver. The receiver coil can include copper having plated layers of nickel and immersion gold formed over the copper. In some embodiments, the thermally conductive layer includes graphite and the electrically conductive layer includes copper. In some instances, the wireless power receiving module can further include a flex circuit formed of a flexible dielectric layer having first and second opposing sides, where the receiver coil is disposed on the first side and the electromagnetic receiver shield is disposed on the second side. The copper layer can be directly attached to the ferrite layer. The receiver coil can have a trace width-to-gap ratio of 70 to 30. Each turn of the plurality of turns can have a wire width that is different than other turns of the plurality of turns. 
     In some embodiments, an electronic device configured to receive magnetic flux for wireless power transfer includes a housing having a charging surface; a battery positioned within the housing; a wireless power receiving module positioned within the housing adjacent to the charging surface to receive magnetic flux for wireless power transfer during a charging event, the wireless power receiving module comprising: a receiver coil comprising a single length of wire wound into a plurality of turns, the receiver coil configured to receive magnetic flux generated by a transmitter coil in a wireless charging device during a charging event and generate a plurality of electric fields; an electromagnetic receiver shield coupled to a first side of the receiver coil, the electromagnetic receiver shield being configured to intercept some of the plurality of electric fields directed away from the receiver coil and allow the magnetic flux to pass through the first electromagnetic receiver shield toward the receiver coil; a ferrite layer coupled to a second side of the receiver coil opposite of the first side, the ferrite layer positioned to redirect magnetic flux during the charging event to improve charging efficiency; and a thermal mitigation shield comprising a thermally conductive layer adhered to an electrically conductive layer where the electrically conductive layer is coupled to ground, enabling the electrically conductive layer to capture stray flux during the charging event, where the ferrite layer is sandwiched between the thermal mitigation shield and the receiver coil. 
     The electromagnetic receiver shield can be grounded to discharge voltage generated by the plurality of electric fields. The electromagnetic receiver shield can include silver. The receiver coil can include copper having plated layers of nickel and immersion gold formed over the copper. The thermally conductive layer can include graphite and the electrically conductive layer can include copper. 
     In some embodiments, a wireless charging system includes a wireless charging device including a transmitter coil configured to generate a magnetic flux across a charging surface and a transmitter shield positioned between the charging surface and the transmitter coil, the transmitter shield made from material that enables the transmitter shield to intercept some electric fields generated during a charging event and directed away from the transmitter coil and allow the magnetic flux to pass through the transmitter shield; an electronic device configured to receive the magnetic flux generated by the wireless charging device during a charging event, the electronic device comprising: a housing having a charging surface; a battery positioned within the housing; and a wireless power receiving module positioned within the housing adjacent to the charging surface to receive magnetic flux for wireless power transfer during a charging event, the wireless power receiving module comprising: a receiver coil comprising a single length of wire wound into a plurality of turns, the receiver coil configured to receive magnetic flux generated by a transmitter coil in a wireless charging device during a charging event and generate a plurality of electric fields; an electromagnetic receiver shield coupled to a first side of the receiver coil, the electromagnetic receiver shield being configured to intercept some of the plurality of electric fields directed away from the receiver coil and allow the magnetic flux to pass through the first electromagnetic receiver shield toward the receiver coil; a ferrite layer coupled to a second side of the receiver coil opposite of the first side, the ferrite layer positioned to redirect magnetic flux during the charging event to improve charging efficiency; and a thermal mitigation shield comprising a thermally conductive layer adhered to an electrically conductive layer where the electrically conductive layer is coupled to ground, enabling the electrically conductive layer to capture stray flux during the charging event, where the ferrite layer is sandwiched between the thermal mitigation shield and the receiver coil. 
     The electromagnetic receiver shield can be grounded to discharge voltage generated by the plurality of electric fields. The electromagnetic receiver shield can include silver. The receiver coil can include copper having plated layers of nickel and immersion gold formed over the copper. The thermally conductive layer can include graphite and the electrically conductive layer can include copper. The wireless charging system can further include a flex circuit formed of a flexible dielectric layer having first and second opposing sides, where the receiver coil is disposed on the first side and the electromagnetic receiver shield is disposed on the second side. 
     A better understanding of the nature and advantages of embodiments of the present invention may be gained with reference to the following detailed description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified diagram illustrating electrical interactions between a transmitter coil and a receiver coil of a wireless charging system during wireless power transfer. 
         FIG. 2  is a simplified diagram illustrating an exemplary wireless charging system including a transmitter shield and a receiver shield according to some embodiments of the present disclosure. 
         FIG. 3A  illustrates an exploded view of an exemplary wireless power receiving module according to some embodiments of the disclosure that can be incorporated into an electronic device to wirelessly receive power from a wireless charger. 
         FIG. 3B  illustrates an exemplary attachment assembly composed of a sheet of single-sided adhesive and double-sided adhesives positioned at edges of an integrated coil and electromagnetic shield in an overlapping arrangement, according to some embodiments of the present disclosure. 
         FIG. 3C  illustrates an exemplary attachment assembly where double-sided adhesives are crescent-shaped and do not overlap with edges of an integrated coil and electromagnetic shield  305 , according to some embodiments of the present disclosure. 
         FIG. 4A  is a simplified cross-sectional view of a portion of the wireless power receiving module shown in  FIG. 3A  according to some embodiments of the disclosure. 
         FIG. 4B  is a simplified cross-sectional view of a portion of the wireless power receiving module shown in  FIG. 4A . 
         FIG. 4C  is a simplified cross-sectional view of a portion of the wireless power receiving module shown in  FIG. 4A  with an adhesive assembly shown in  FIG. 3B , according to some embodiments of the present disclosure. 
         FIG. 4D  is a simplified cross-sectional view of a portion of the wireless power receiving module shown in  FIG. 4A  with an adhesive assembly shown in  FIG. 3C , according to some embodiments of the present disclosure. 
         FIG. 5  is a simplified top view of the wireless power receiving module shown in  FIGS. 4A and 4B . 
         FIGS. 6A-6C  illustrate simplified perspective, top and bottom plan views of a wireless power receiving module according to some embodiments of the disclosure. 
         FIG. 7  illustrates a simplified top-down view of a receiver coil formed of a wire having turns that vary in widths according to some embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     During wireless power transfer in a wireless charging system, numerous electrical interactions can occur between a transmitter coil and a receiver coil in the wireless charging system. Some of the electrical interactions are intended interactions between the transmitter and receiver coil, while other electrical interactions are unintended interactions that can cause inefficiencies in power transfer and create issues in the electronic device. For example,  FIG. 1  is a simplified diagram illustrating electrical interactions between a transmitter coil  102  and a receiver coil  104  of an exemplary wireless charging system  100  during wireless power transfer. Transmitter coil  102  may be disposed within a wireless charging device, such as a wireless charging mat, and receiver coil  104  may be disposed within a consumer electronic device, such as a smart phone, smart watch, tablet, laptop, and the like. The electronic device may rest on the wireless charging device at interface  112  to enable power transfer. 
     Transmitter coil  102  and receiver coil  104  can be positioned substantially concentric to one another to enable efficient power transfer by means of magnetic induction. During wireless power transfer, transmitter coil  102  can generate time-varying magnetic flux  106 , which can propagate through both device housings at interface  112  and be received by receiver coil  104 . Time-varying magnetic flux  106  interacts with receiver coil  104  to generate a corresponding current in receiver coil  104 . The generated current can be used to charge a battery for operating the electronic device. 
     In addition to time-varying magnetic flux  106 , however, electric fields  108  and  110  can be unintentionally generated between transmitter and receiver coils  102  and  104  during wireless power transfer. For instance, when transmitter coil  102  generates magnetic flux  106 , a large voltage difference can exist between transmitter coil  102  and receive coil  104 . The voltage on transmitter coil  102  in some cases can be larger than the voltage on receiver coil  104 , thereby orienting some electric fields  108  toward receiver coil  104  and causing unintended voltage to be generated in receiver coil  104 . In some additional cases, voltage existing on receiver coil  104  may also orient some electric fields  110  toward transmitter coil  102  and cause detrimental voltage to be generated on transmitter coil  102 . Detrimental voltages generated on receiver coil  104  may disturb and/or disrupt the operation of sensitive components disposed proximate to receiver coil  104 , such as touch-sensitive devices like a touch-sensitive display. And, detrimental voltages generated on transmitter coil  102  may cause inefficiencies in power transfer. 
     Embodiments of the disclosure describe a wireless charging system that mitigates the unintentional generation of detrimental voltage on a receiver and/or a transmitter coil during wireless power transfer. One or more electromagnetic shielding components may be incorporated in the wireless charging system to prevent electric fields from generating detrimental voltages on the receiver and/or transmitter coils, while allowing time-varying magnetic flux to freely propagate between the transmitter and receiver coils to perform wireless power transfer. 
     In some embodiments, a transmitter shield can be implemented in a wireless charging device to prevent detrimental voltage from being generated on a receiver coil in an electronic device. The transmitter shield can be positioned in the wireless charging device to intercept electric fields generated by the transmitter coil to prevent the electric fields from exposing on the receiver coil. As a result, the intercepted electric fields may generate voltage on the transmitter shield instead of on the receiver coil. This voltage can then be discharged by routing the voltage to ground, thereby disposing of the detrimental voltage and preventing it from affecting sensitive electronic components in the electronic device. A description of a transmitter shield according to some embodiments of the disclosure is set forth in U.S. Provisional Patent Application 62/399,082 entitled “ELECTROMAGNETIC SHIELDING FOR WIRELESS POWER TRANSFER SYSTEMS” filed on Sep. 23, 2016. The &#39;082 provisional application is assigned to Apple Inc., the assignee of the present application, and is incorporated by reference herein in its entirety for all purposes. 
     In some embodiments, a receiver shield can be implemented within a wireless power receiving module of the wireless charging system to prevent detrimental voltage from being generated on the transmitter coil in the wireless charging device. The receiver shield can be positioned in the electronic device to intercept electric fields generated by the receiver coil so that the electric fields are not exposed to the transmitter coil. Voltage generated in the receiver shield can be discharged to ground to prevent detrimental voltage from being generated on the transmitter coil. Aspects and features of embodiments of such a wireless power receiving module are discussed in further detail herein. 
       FIG. 2  is a simplified diagram illustrating an exemplary wireless charging system  200  including a transmitter shield  202  and a receiver shield  204 , according to some embodiments of the present disclosure. Transmitter shield  202  may be positioned in front of transmitter coil  102  so that magnetic flux  106  is directed toward transmitter shield  202 . For instance, transmitter shield  202  is positioned between transmitter coil  102  and receiver coil  104  during wireless power transfer so that magnetic flux  106  first passes through transmitter shield  202  before reaching receiver coil  104 . In some embodiments, transmitter shield  202  can be positioned between interface  112  and transmitter coil  102  when an electronic device rests on the wireless charging device to perform wireless power transfer. Accordingly, transmitter shield  202  and transmitter coil  102  can both be positioned within the wireless charging device. Transmitter shield  202  can be substantially transparent to magnetic flux  106  so that a substantial percentage of magnetic flux  106  generated by transmitter coil  102  is received by receiver  104 . 
     While transmitter shield  202  can be substantially transparent to magnetic flux  106 , transmitter shield  202  can, on the other hand, be substantially opaque to electric field  108  such that electric field  108  is substantially blocked by transmitter shield  202 . This prevents electric field  108  from exposing on receiver coil  104  and generating an detrimental voltage on receiver coil  104 . Because transmitter shield  202  substantially blocks electric field  108  before it can reach receiver coil  104 , electric field  108  may generate voltage on transmitter shield  202  instead of receiver coil  104 . The amount of voltage generated on transmitter shield  202  may correspond to the amount of voltage that would have been generated on transmitter coil  104  had transmitter shield  202  not been present. 
     In some embodiments, voltage generated on transmitter shield  202  can be removed so that the voltage does not permanently remain on transmitter shield  202 . As an example, voltage on transmitter shield  202  can be discharged to ground. Thus, transmitter shield  202  can be coupled to a ground connection  206  to allow voltage on transmitter shield  202  to be discharged to ground. Ground connection  206  can be a ground ring or any other suitable conductive structure coupled to ground that can remove voltage from transmitter shield  202 . 
     Similar to transmitter shield  202 , a receiver shield  204  may also be implemented in wireless charging system  200  to prevent detrimental voltage from being generated on transmitter coil  102  from electric field  110  generated by receiver coil  104 . Receiver shield  204  may be positioned in front of receiver coil  104  so that magnetic flux  106  first passes through receiver shield  204  before reaching receiver coil  104 . In some embodiments, receiver shield  204  and receiver coil  104  are positioned within a wireless power receiving module which in turn is positioned within a housing of an electronic device as described below with respect to  FIG. 3A . Within the module, receiver shield  204  can be positioned between interface  112  and receiver coil  104  when the electronic device rests on a wireless charging device to perform wireless power transfer. 
     Similar to transmitter shield  202 , receiver shield  204  can be substantially transparent to magnetic flux  106  so that a substantial percentage of magnetic flux  106  generated by transmitter coil  102  passes through receiver shield  204  and is received by receiver  104 , while receiver shield  204  can be substantially opaque to electric field  110  such that electric field  110  is substantially blocked by receiver shield  204 . This prevents electric field  110  from reaching transmitter coil  102  and generating an detrimental voltage on transmitter coil  102  while enabling wireless power transfer. Like transmitter shield  202 , receiver shield  204  may also be grounded so that voltage generated by electric field  110  may be discharged to a ground connection  208 . Ground connection  208  may be a structure similar to ground connection  206  in some embodiments, or it may be the same structure as ground connection  206  in other embodiments. 
     By incorporating transmitter and receiver shield  202  and  204  into wireless charging system  200 , the wireless charging device and the electronic device within which transmitter and receiver shields  202  and  204  are implemented, respectively, are exposing their grounds to each other. This mutes any ground noise caused by the electrical interactions between transmitter and receiver coils  102  and  104 . As can be appreciated by disclosures herein, transmitter shield  202  and receiver shield  204  are shielding structures that are able to block the passage of electric fields, yet allow the passage of magnetic flux. 
     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. 3A  illustrates an exploded view of a wireless power receiving module  300  according to some embodiments of the disclosure that can be incorporated within a housing  325  of a portable electronic device. As shown in  FIG. 3A , wireless power receiving module  300  can include at least three separate shields including an integrated coil and electromagnetic shield  305 , a ferrite shield  310 , and a thermal shield  315  along with an adhesive component  320  that attaches module  300  to housing  325 . 
     Adhesive component  320  can be a single sheet of an adhesive material, such as pressure sensitive adhesive (PSA), that attaches wireless power receiving module  300  to housing  325 . In other embodiments, instead of being attached to housing  325  with a single sheet of adhesive material, wireless power receiving module  300  can be attached to housing  325  with an attachment assembly that is composed of more than one sheet of adhesive material, as discussed herein with respect to  FIG. 3B . 
       FIG. 3B  illustrates an exemplary attachment assembly  332  composed of a sheet of single-sided adhesive  336  and double-sided adhesives  334   a  and  334   b  positioned at edges of integrated coil and electromagnetic shield  305  in an overlapping arrangement, according to some embodiments of the present disclosure. Double-sided adhesives  334   a  and  334   b  can be formed of PSA to attach thermal shield  315  to housing  325 . Single-sided adhesive  336  can be attached to housing  325  and act as an anti-splinter film in case of a breakage event. In particular embodiments, single-sided adhesive  336  may not be coupled to wireless power receiving module  300  so that ferrite shield  310  and integrated coil and electromagnetic shield  305  are decoupled from housing  325 . By decoupling ferrite shield  310  and integrated coil and electromagnetic shield  305  from housing  325 , vibrations caused by time-varying magnetic fields generated during wireless power transfer may not be transferred to housing  325 , thereby minimizing acoustic coupling between ferrite shield  310  and integrated coil and electromagnetic shield  305  from housing  325 . In some embodiments, single-sided adhesive  336  is formed of polyimide. As shown in  FIG. 3B , double-sided adhesives  334   a  and  334   b  can be positioned around the perimeter of integrated coil and electromagnetic shield  305 . In some instances, double-sided adhesives  334   a  and  334   b  can overlap edges of integrated coil and electromagnetic shield  305 , as indicated by the dotted profile of integrated coil and electromagnetic shield  305 . 
     Although  FIG. 3B  illustrates attachment assembly  340  as having double-sided adhesives  334   a  and  334   b  positioned around the perimeter of integrated coil and electromagnetic shield  305  in such a way that overlaps with edges of integrated coil and electromagnetic shield  305 , embodiments are not so limited. Other attachment assemblies do not have to have double-sided adhesives that overlap with edges of integrated coil and electromagnetic shield  305 .  FIG. 3C  illustrates an exemplary attachment assembly  338  where double-sided adhesives  340   a - d  are crescent-shaped and do not overlap with edges of integrated coil and electromagnetic shield  305 , according to some embodiments of the present disclosure. Double-sided adhesives  340   a - d  are shaped as a crescent to conform to the outer profile of integrated coil and electromagnetic shield  305 . As will be discussed further herein, double-sided adhesives  340   a - d  attach ferrite shield  310  to housing  325  without overlapping with integrated coil and electromagnetic shield  305 . In some embodiments, single-sided adhesive  336  can have a shape that corresponds with the shape of integrated coil and electromagnetic shield  305 . For instance, single-sided adhesive  336  can be substantially circular. 
     With reference back to  FIG. 3A , integrated coil and electromagnetic shield  305  can act as, for example, receiver coil  104  and receiver shield  204  shown in  FIG. 2  enabling wireless power receiving module  300  to wirelessly receive power transmitted from a wireless power transmitting coil, such as coil  102  shown in  FIG. 2 . When positioned within a portable electronic device, the receiver shield portion of the integrated coil and shield is positioned between the receiver coil portion and the charging surface of the electronic device. Thus, the receiver shield is positioned between the receiver coil and the transmitter coil and serves to prevent capacitive coupling to the transmit coil in the wireless charging device. Ferrite shield  310  acts as a B-field or magnetic field shield redirecting magnetic flux to get higher coupling to the transmit coil resulting in improved charging efficiency and helping prevent magnetic flux interference. Thermal shield  315  can include a graphite or similar layer that provides thermal isolation between wireless power receiving module  300  and the battery and other components of the electronic device in which the wireless power receiving module  300  is incorporated. Thermal shield  315  can also include a copper layer that is tied to ground and contributes to the thermal shielding while also capturing stray flux. Further details of the three different shields within module  300  are discussed below in conjunction with  FIGS. 4A and 4B . 
     Still referring to  FIG. 3A , in some embodiments a wireless power receiving module according to embodiments of the disclosure can be an integrated module made as thin as possible as described in more detail below in order to not unduly increase the thickness of the electronic device within which the module is positioned. Additionally, housing  325  can include a cutout area  330  sized and shaped to receive the wireless power receiving module thereby saving additional space within the electronic device within which the module is incorporated and allowing the electronic device to be made even thinner. 
     Reference is now made to  FIG. 4A , which is a simplified cross-sectional view of a portion of a wireless power receiving module  420  positioned within a housing of an electronic device  400 . Wireless power receiving module  420  can be, for example, wireless receiving module  300  shown in  FIG. 3A , while electronic device  400  can be any suitable portable electronic device, such as a smart phone, tablet computer, laptop computer, smart watch, or other type of consumer electronic device. As shown in  FIG. 4B , electronic device  400  can include a housing  402  that defines the shape and size of the portable electronic device. Housing  402  can be, for example, housing  325  shown in  FIG. 3A  and can be formed from or include a relatively stiff and strong material such as a clad support plate. In some embodiments a glass plate  404  having a layer of ink  406  coated on the inside surface of the glass plate can be attached to housing  402  by an adhesive layer  408  to form a back surface of electronic device  400 . In some embodiments ink layer  406  has low electrical conductivity and the color of the ink layer can be chosen to match other exterior surfaces of electronic device  400 . Housing  402  can include a cutout region  415  that accepts wireless power receiving module  420  as described above with respect to cutout  330  allowing module  420  to occupy a minimum amount of space in the z direction within the electronic device  400 . 
     With reference back to  FIG. 4A , a battery  410  can be positioned within housing  402  along with other components (not shown) of the electronic device including but not limited to one or more processors, memory units, communications circuitry, sensors and the like that enable the electronic device to perform its intended functions. Battery  410  can be attached to housing  402  by, for example, a battery adhesive  412 . 
     Wireless power receiving module  420  can be positioned within cutout region  415  to minimize the space in the z direction the module requires within portable electronic device  400 . As shown, wireless power receiving module can include three separate shields including an integrated coil and electromagnetic shield  430 , a ferrite shield  440  and a thermal shield  450 . Integrated coil and electromagnetic shield  430  can be representative of integrated coil and electromagnetic shield  315  shown in  FIG. 3A ; ferrite shield  440  can be representative of ferrite shield  310  and thermal shield  450  can be representative of thermal shield  305 . An adhesive  460 , such as a pressure sensitive adhesive, can attach module  420  to ink-coated glass layer  404 / 406  and act as an anti-splinter film in case of a breakage event. 
     In some embodiments of the disclosure, a small gap  470  can be formed between an upper surface of the wireless power receiving module and a lower surface of battery  410 . The gap provides a level of tolerance during manufacturing to ensure that wireless power receiving  420  and battery  410  are not in physical contact with each other and thus ensure that the wireless power receiving module does not interfere with attachment of the battery to housing  402 . 
     As shown in  FIG. 4B , integrated coil and electromagnetic shield  430  can include a flexible dielectric base layer  432 , such as a polymide layer, with an electromagnetic receiver shield  434  formed directly on one side of polymide layer  432  and a copper receiver coil  436  can be formed directly on the opposing side. Having receiver shield  434  and receiver coil  436  formed directly on opposing sides of base layer  432  allows a single carrier layer to be used for both the receiver shield and receiver coil and thus enables the overall thickness of wireless power receiving module  420  to be reduced. To further reduce thickness, some embodiments of the disclosure do not include a coverlay or other type of protective layer over the flex as is used for traditional flex circuits to encapsulate and protect the circuits formed on the flex. Instead, some embodiments of the disclosure plate the receiver coil  436  with an electroless nickel plating process followed by and a thin layer of immersion gold that protects the nickel from oxidation. 
     Receiver shield  434  can be formed from a material having properties that enable magnetic flux to pass through but prevent electric fields from passing through. In some embodiments, receiver shield  434  is formed from of silver. During a wireless power charging event, receiver shield  434  is positioned between copper receiver coil  436  and the wireless power charger to intercept electrical fields associated with receiver shield  434  during wireless power transfer to prevent detrimental voltage from being generated on the transmitter coil, while copper receiver coil can be made relatively thick (e.g., 70 microns in some embodiments) to provide strong inductive performance during the charging event. 
     Ferrite shield  440  includes a relatively thick layer of ferrite material  442  sandwiched between a thin adhesive layer  444  and a thin thermoplastic polymer layer  446 , such as a PolyEthylene Terephthalate film. Adhesive layer  444  and thermoplastic polymer layer  446  provide a carrier for ferrite layer  442  that contains the ferrite and prevents minor cracks, burrs or other imperfections at the ferrite surface from coming into contact with other components of the wireless power receiving module. Ferrite shield  440  is positioned within wireless power receiving module  420  on the opposite side of copper receiving coil  436  as electromagnetic shield  434 . 
     Thermal shield  450  can include a thermal layer  452  adhered to a conductive layer  454  by a thin conductive adhesive (not shown). Thermal layer  452  provides thermal isolation between wireless power receiving module  300  and various components of electronic device  400  including battery  410 . Conductive layer  454  provides additional thermal shielding and can be coupled to ground to capture stray flux and prevent such flux from interfering with the display (not shown) or other components of device  400 . While not shown in  FIG. 4B , a first thin layer of conductive adhesive (e.g., 5 microns) can adhere thermal layer  452  to conductive layer  454 , a second thin layer of conductive adhesive (e.g., 5 microns) can adhere conductive layer  454 , and thus thermal shield  450 , to ferrite shield  440 , and a thin thermoplastic polymer layer, such as a 5 micron PolyEthylene Terephthalate film, can be used to cover the top exterior surface of graphite layer  452 . In some embodiments, thermal layer  452  can be formed of any suitable material that has high thermal conductivity, such as but not limited to, graphite. And, conductive layer  454  can be formed of any suitable material that has high electrical conductivity, such as but not limited to, aluminum, stainless steel, nickel, and metal alloys including at least one of the aforementioned electrically conductive materials. 
     As shown in each of  FIGS. 4A, 4B and 5 , thermal shield  450  can include a section  456  that extends beyond the edges of cutout  415  over housing  402  to provide continuous metal coverage behind wireless power receiving module  420  to prevent flux leakage from occurring in the gap formed between the outer edges of module  420  and the inner edges of housing  402  in cutout region  415 . Referring to  FIG. 5 , when wireless power receiving module  420  is positioned within cutout  415 , a gap  510  can extend around the entire outer periphery  502  of portions  430 ,  440  and  460  of wireless power receiving module  420  between the wireless power receiving module and an inner periphery  504  of the cutout portion of housing  402 . Section  456  can extend over gap  510  and over the inner edge of the cutout of housing  402  completely covering the gap on all sides of copper coil  436  integrated coil and electromagnetic shield  430 . 
       FIGS. 4A and 4B  illustrate cross-sections of device  400  where adhesive  460  is a single sheet of adhesive material.  FIG. 4C , however, illustrates a cross-sectional view of device  400  where adhesive  460  is an attachment assembly  462  (such as attachment assembly  332  discussed herein with respect to  FIG. 3B ) composed of a sheet of single-sided adhesive  464  and double-sided adhesive  466  positioned at an edge of integrated coil and electromagnetic shield  460  in an overlapping arrangement. In some embodiments, single-sided adhesive  464  can be attached to ink layer  406  and not integrated coil and electromagnetic shield  430 . Double-sided adhesive  466  can be coupled between integrated coil and electromagnetic shield  430  and ink layer  406 . 
       FIG. 4D  illustrates a cross-sectional view of device  400  where adhesive  460  is an attachment assembly  468  (such as attachment assembly  338  discussed herein with respect to  FIG. 3C ) composed of a sheet of single-sided adhesive  470  and double-sided adhesive  472  positioned at an edge of integrated coil and electromagnetic shield  460  in a non-overlapping arrangement. In some embodiments, single-sided adhesive  470  can be attached to ink layer  406  and not integrated coil and electromagnetic shield  430 . Double-sided adhesive  466  can be coupled between ferrite shield  440  and ink layer  406 . These different adhesive configurations can widen manufacturing tolerances of the overall height of the stack of components, as well as decrease the amount of surface area covered by the adhesive material. 
     As stated above, in various embodiments wireless power receiving module  400  is manufactured to be very thin. As an example, in some embodiments wireless power receiving module  400  fits within the height of housing  402  and battery adhesive  412 . In one particular embodiment, wireless power receiving module  400  is no more than 250 microns thick with thermal shield  450  being approximately 70 microns thick, ferrite shield  440  being approximately 110 microns and integrated coil and electromagnetic shield  430  being approximately 70 microns thick. 
     Referring now to  FIGS. 6A-6C , which depict perspective ( FIG. 6A ) as well as top ( FIG. 6B ) and bottom ( FIG. 6C ) plan views of integrated coil and electromagnetic shield  430  according to some embodiments of the disclosure. As shown in  FIGS. 6B and 6C , receiver coil  436  is positioned on a first side of the flex circuit while receiver shield  434  is positioned on the second, opposite side. Receiver shield  434  can have dimensions that correspond to the dimensions of receiver coil  436 . In the embodiment depicted in  FIGS. 6A-6C , receiver coil  436  and receiver shield  434  each have a flat donut or ring shape but in other embodiments the receiver shield can have a different shape that corresponds to the receiver coil, such as a square, rectangle, hexagon, triangle, and the like. Comparing  FIG. 6C  to  FIG. 6B , one can see that electromagnetic receiver shield  434  is large enough to cover the entire receiver coil  436  so that receiver coil  436  is completely shielded by receiver shield  434 . 
     A connection terminal  602  having one or more contact pads can be formed on the first side of the flex along with receiver coil  436 . Connection terminal  602  can provide electrical routes through which current induced in receiver coil  436  can be routed to provide power to charge a battery in the electronic device within which the wireless power receiving module is incorporated. Additionally, connection terminal  602  can include one or more ground lines for routing voltage in receiver shield  436  to ground. 
     As shown in the figures, when laid out upon dielectric base layer  432 , receiver coil  436  can have a flat, disc-like shape formed of a winding that spirals from an inner diameter to an outer diameter. Likewise, receiver shield  434  can also have a disk-like shape that has a corresponding inner and outer diameter. Receiver shield  434  can include a gap  610  formed between opposing ends  612 ,  614  of the receiver shield that are spaced apart from each other defining gap  610 . Gap  610  can provide space for a connection segment  604  as discussed below. During operation, an electric field from receiver coil  436  can generate a voltage in receiver shield  434 . The generated voltage may flow across receiver shield  434  to at least one of ends  612  and  614  and be discharged to ground. 
     As shown in  FIG. 6C , the second side of the flex can also be used for a second layer of copper to wrap the inner turn of receiver coil  436  out to a termination in connection terminal  602  via a segment  604  and to ground the electromagnetic shield. The routing for segment  604  can be maintained in a very limited region  606  as shown in  FIG. 6C . Thus, the second layer of copper is hidden in a very limited region and can be a different thickness (thinner) than the first layer that makes up coil  436  on the first side. Additionally, the additional thickness of the integrated coil and electromagnetic shield  430  in the limited area where segment  604  is formed can be accommodated for in the overall thickness of the wireless power receiving module by creating a cutout region in adhesive layer  450  corresponding to region  606  in which segment  604  is formed. Such a cutout region is shown, for example, in  FIG. 3A  as region  322  while an additional cutout region  312  can be formed in the ferrite shield to enable electrical connections to be made to the termination provide access to accommodate the contact pads  602  as shown in  FIG. 3A  as region  312 . 
     In some embodiments, connection to ground can be established at end  612  of receiver shield  434  closest to the top of region  606  so that voltage generated on receiver shield  434  can be discharged to ground through segment  604 . While providing a connection to ground at end  612  helps discharge voltage on receiver shield  434 , performance of receiver shield  434  can be improved by including a cut  616  in receiver shield  434  positioned opposite of region  606  to electrically separate receiver shield  434  into two halves. An additional connection to ground can be provided at end  614  closest to the bottom of region  606  so that both halves of receiver shield  434  can be coupled to ground to discharge any voltage generated in receiver shield  434 . Without cut  616  in receiver shield  434 , the potential difference between ends  612  and  614  may be based on the voltage captured by the entire surface area of receiver shield  434 . This can cause a large potential difference to build up between ends  612  and  614 , and can be difficult to discharge to ground. By including cut  616 , the potential difference can be substantially decreased, such as by a half, thereby making it easier to discharge the voltage to ground. 
     While not shown in the figures, in some embodiments, a NFC antenna coil or similar antenna coil can be formed between (intertwined with) the windings of receiver coil  436 . For example, the gap between adjacent turns of the receiver coil can be made large enough to include a winding of an NFC antenna coil between adjacent receiver coil windings while maintaining an air gap between the edges of the NFC coil and the receiver coil. 
     With reference back to  FIG. 6B , receiver coil  436  can be formed of a single length of wire that is wound into a plurality of turns. The wire can be wound about a center point and in increasing radii such that the resulting coil is substantially planar. As further shown in  FIG. 6B , each turn is separated by a gap  438  that separates adjacent turns of receiver coil  436 . Often times, the coil width-to-gap ratio in conventional receiver coils is selected to maximize the size of the receiver coil and to achieve the greatest wire width that the receiver can fit in its allotted space. According to some embodiments, however, the coil width-to-gap ratio is not selected to maximize the size of receiver coil  436  or to achieve the greatest wire width. Rather, the coil width-to-gap ratio can be tailored to maximize efficiency according to an operating frequency used during wireless power transfer. Higher operating frequencies tend to work better with coils having smaller wire widths. Thus, in some embodiments, the wire width-to-gap ratio can vary between 60:40 to 80:20, particularly 70:30 in some instances for an operating frequency of approximately 350 kHz. Furthermore, by not maximizing the wire width, the receiver coil may not have significantly more conductive material than a transmitter coil from which it is receiving power, which thereby may not significantly impact the operation of the transmitter coil during wireless power transfer. 
     In addition to coil width-to-gap ratio, an inner diameter  616  and an outer diameter  618  of receiver coil  436  can affect the charging characteristics of receiver coil  436  when it is placed against one or more transmitter coils. In some embodiments, inner diameter  616  is selected to correspond to the inner diameter of a transmitter coil from which receiver coil  436  receives wireless power. Outer diameter  618 , on the other hand, can correspond to the outer diameter of the transmitter coil, or it can be greater than the outer diameter of the transmitter coil. When outer diameter  618  corresponds to the outer diameter of the transmitter coil, the charging efficiency between the two coils has a maximum efficiency when the two coils are aligned with each other, but may drastically decrease as the two coils become less aligned. This may be particularly beneficial in instances where alignment between the two coils is easily achieved or is intended to be achieved during wireless power transfer. By increasing outer diameter  618  however, the maximum efficiency may decrease but may result in less of a decrease in efficiency as the two coils become less aligned. This may be particularly useful in instances where perfect alignment between the two coils is less of a priority and that having a broader charging region is desired. In some embodiments, inner diameter  616  corresponds to an inner diameter of a transmitter coil from which it receives power, and outer diameter  618  is greater than the outer diameter of the transmitter coil. 
     As shown herein with respect to  FIGS. 6A and 6B , the each turn of wire in receiver coil  436  has the same width as the other turns in receiver coil  436 ; however, embodiments are not limited to such configurations. Some embodiments can have turns in receiver coil  436  that have different widths. By varying the wire widths, receiver coil  700  can achieve a higher quality factor than coils that do not vary in wire widths. Furthermore, the varied wire widths allow for lower alternating current resistance (ACR) during wireless power transfer. 
       FIG. 7  illustrates a simplified top-down view of a receiver coil  700  formed of a wire having turns that vary in widths, according to some embodiments of the present disclosure. Receiver coil  700  can wind from an inner turn  702  to an outer turn  704 , thereby resulting in a plurality of turns that form receiver coil  700 . In some embodiments, each turn of receiver coil  700  has a different thickness than other turns in receiver coil  700 . For instance, the widths of the wire can progressively increase each turn from inner turn  702  to outer turn  704 . However, outer turn  704  may not necessarily be have the largest width. In certain embodiments, a turn  706  adjacent to outer turn  704  can have the largest width, such that the wire width decreases from turn  706  to outer turn  704 . Although  FIG. 7  illustrates receiver coil  700  being configured with varying wire widths that first increases from inner turn  702  to turn  706  and then decreases from turn  706  to outer turn  704 , embodiments are not limited to such configurations. Any arrangement of wire widths can be implemented to form receiver coil  700 . 
     As can be appreciated from the illustration of  FIG. 7 , each turn of wire has a constant wire width. Meaning, the width of the wire along an entire turn does not decrease in width, e.g., does not taper to a narrower width or a wider width in a single turn. In some embodiments, a transition region  708  can be a region of receiver coil  700  where wire widths change to respective wire widths for each turn. Transition region  708  can be relatively small compared to the rest of the turn so that a vast majority of the turn has a constant wire width. 
       FIGS. 6A-6B and 7  illustrate receiver coils formed of a patterned conductive trace on a flexible circuit board. It is to be appreciated however that embodiments are not limited to receiver coils patterned on flexible circuit boards. In certain embodiments, receiver coils discussed herein can be formed of stranded wires. 
     Although the invention has been described with respect to specific embodiments, it will be appreciated that the invention is intended to cover all modifications and equivalents within the scope of the following claims. Additionally, spatially relative terms, such as “bottom,” “top,” “upward,” or “downward” and the like may be used herein to describe an element and/or feature&#39;s relationship to another element(s) and/or feature(s) as, for example, illustrated in the accompanying figures. It will be understood, however, that the spatially relative terms are intended to encompass different orientations of the device in use and/or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as a “bottom” surface may then be oriented “above” other elements or features. The device may be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Metadata:
Filing Date: 20170911
Publication Date: 20180925
Grant Date: 20180925
Priority Date: 20170215
Inventors: LARSSON, KARL RUBEN F.
JOL, ERIC S.
GRAHAM, Christopher S.
Oro, Aaron A.
Assignee: APPLE INC
CPC Classifications: [{"code": "H05K9/0058", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/24", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F38/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/28", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/28", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F38/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/36", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01F27/24", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/12", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J7/025", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/0037", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/28", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/22", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J50/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/361", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/361", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/361", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/36", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/22", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J50/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F38/14", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01F27/24", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/28", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/36", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F38/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/36", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/79", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/79", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/79", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 60856996