In March Patently Apple covered an Apple patent related to wireless charging a future AirPods case on AirPower where a patent figure illustrated the AirPower with overlapping wireless transmitter coils. Over the weekend Patently Apple discovered a master patent which incorporates some 20 previous patents on AirPower into a single patent. The patent covers 17 distinct segments covering the entire makeup of AirPower which should be coming to market sometime in Q4 2018. In case you missed it, Patently Apple posted a patent report on Saturday covering a unique inductive power transfer accessory for AirPower that you could check out here.

In this current patent's background, Apple notes that wireless charging devices have been developed to wirelessly charge electronic devices without the need for a charging cord. For example, 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 field 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 have a number of disadvantages. For instance, some wireless charging devices require an electronic device to be placed in a very confined charging region on the charging surface in order for the electronic device being charged to receive power. If an electronic device is placed outside of the charging region, the electronic device may not wirelessly charge or may charge inefficiently and waste power. This limits the ease at which an electronic device can be charged by the wireless charging device.

Apple's invention covers a wireless charging device (AirPower) that includes a charging surface having a broad charging region upon which an electronic device can be placed to wirelessly receive power.

In some embodiments the wireless charging device can be a wireless charging mat that includes an arrangement of wireless power transmitters beneath the charging surface defining a charging region. The wireless charging mat allows the electronic device to be charged at any location within the charging region, thereby increasing the ease at which electronic devices can be charged by the mat.

In some embodiments a wireless charging device includes: a housing having an outer perimeter and a charging surface within the outer perimeter, the housing including a first wall and a second wall that define an interior cavity; and a transmitter coil arrangement disposed within the interior cavity and below the planar charging surface. The transmitter coil arrangement includes: a plurality of transmitter coils arranged in different layers, each transmitter coil having a first termination end, a second termination end, and a coil of wire that winds from an inner diameter to an outer diameter between the first and second termination ends; where the first termination end of each transmitter coil is disposed within the inner diameter of its respective coil of wire and the second termination end of each transmitter coil is disposed outside the outer diameter of its respective coil of wire.

In some additional embodiments, a wireless charging device includes: a housing having an outer perimeter and a planar charging surface within the outer perimeter of the wireless charging device, the housing including first and second shells defining an interior cavity; and a transmitter coil arrangement disposed within the interior cavity and below the planar charging surface. The transmitter coil arrangement includes: a plurality of transmitter coils arranged in different layers, each transmitter coil having a first region and a second region having more turns than the first region; where the plurality of transmitter coils comprises a plurality of inner transmitter coils and a plurality of outer transmitter coils positioned around the inner transmitter coils; and where the first regions of the outer transmitter coils are oriented toward the outer perimeter of the wireless charging device.

In some further embodiments, a wireless charging system includes: an electrical device comprising a receiver coil configured to generate a current to charge a battery when exposed to a time-varying magnetic flux; and a wireless charging mat configured to generate the time-varying magnetic flux to wirelessly charge the electronic device. The wireless charging mat includes: a housing having an outer perimeter and a charging surface within the outer perimeter, the housing including a first wall and a second wall that define an interior cavity; and a transmitter coil arrangement disposed within the interior cavity and below the planar charging surface. The transmitter coil arrangement includes: a plurality of transmitter coils arranged in different layers, each transmitter coil having a first termination end, a second termination end, and a coil of wire that winds from an inner diameter to an outer diameter between the first and second termination ends; where the first termination end of each transmitter coil is disposed within the inner diameter of its respective coil of wire and the second termination end of each transmitter coil is disposed outside the outer diameter of its respective coil of wire.

Apple's patent FIG. 10 below illustrates a simplified diagram illustrating an exemplary transmitter coil arrangement where transmitter coils are arranged in different radial directions based on their position in the transmitter coil arrangement

Apple's patent FIG. 13A above illustrates a simplified diagram illustrating an exemplary coil of wire formed of a plurality of thin wires; FIG. 13B is a simplified diagram illustrating a cross-sectional view of a single turn of a coil of wire formed of a plurality of thin wires.

Another key aspect of the AirPower system includes a 'Bobbin." Apple notes that each coil of wire is wound around, and the termination ends of each coil are attached to, a central, disc-shaped support structure known as a "bobbin."

The structure formed by combining the coil of wire and the bobbin is sometimes referred to as "a transmitter coil." The bobbin is a support structure that not only provides structural integrity for the coil of wire, but also provides a structure to which the termination ends can attach for coupling with a respective pair of contact pins. The contact pins can electrically couple the coil of wire to a driver board for operating the coil of wire as a transmitter coil for wireless charging.

Apple's patent FIG. 23 illustrates AirPower assembly. It illustrates an exploded view of AirPower having transmitter coils with bobbins, according to some embodiments of the present disclosure.

Apple's patent FIG. 25A below is a top-view illustration of an exemplary electromagnetic shield #2500. The electromagnetic shield can include a shielding body #2502 and a conductive border #2504 around a perimeter of shielding body.

The shielding body can intercept electric fields generated by one or more transmitter coils in AirPower and discharge the voltage generated by the intercepted electric fields to ground through the conductive border.

In some embodiments, the shielding body is constructed of a material having properties that enable magnetic flux to pass through the shielding body but prevent electric fields from passing through. For instance, the shielding body can be formed of a silver laminate on a layer of pressure sensitive adhesives (PSA).

Apple's patent FIG. 30 above is a bottom-view illustration of drop frame #2436 coupled to a driver board #2426. The illustration shows the drop frame and driver board without a bottom shield so that the placement of a plurality of packaged electrical components #3002 can be seen with respect to drop frame.

In the end, AirPower is designed to be efficiently charged across a vast majority, if not an entire area. Arrays of transmitter coils disposed below the charging surface may generate time-varying magnetic fields capable of inducing current in a receiver of the electronic device or of a docking station with which the electronic device is coupled.

AirPower may include multiple transmitter coil layers. Each layer can include an array of transmitter coils arranged in a grid pattern and configured to generate magnetic fields in a corresponding grid pattern. Spaces between each transmitter coil in the layer may be a "dead zone," i.e., a region where a magnetic field is not generated. Thus, the multiple transmitter coil layers can be arranged so that there are minimal dead zones across a charging surface of the wireless charging mat.

In some embodiments, AirPower includes three transmitter coil layers where each layer is arranged to fill dead zones in the other two layers. For instance, magnetic fields generated by coils in a first layer can fill in dead zones in the second and third layers.

Likewise, magnetic fields generated by coils in the second layer may fill in dead zones in the first and third layers; and magnetic fields generated by coils in the third layer can fill in dead zones in the first and second layers.

Accordingly, the three transmitter coil layers can collectively generate magnetic fields that span across the charging surface, thereby enabling an electronic device to be charged across a vast majority of the charging surface.

Overall, Apple's patent is broken down in distinct segments covering the following:

• Wireless Charging Mat
• Arrangement of Transmitter Coils
• Transmitter Coil Patterns
• Base Pattern
• Rosette Pattern
• Expanding Transmitter Coil Patterns
• Coverage of Transmitter Coil Patterns
• Rotational Arrangement of Transmitter Coils
• Transmitter Coil Structure
• Transmitter Coil Wiring
• Bobbin
• Angle Transmitter Coil
• Parallel Transmitter Coil
• Multi-Layer Arrangement of Transmitter Coils
• Transmitter Coils Without Bobbins
• Wireless Charging Mat Assembly, and
• Hybrid PCB and Stranded Coil Wireless Charging Mat

Apple's master patent application covers a series of patents filed in 2017 and combined in this patent that was published last week and discovered in Europe over the weekend. AirPower should finally surface in the marketplace sometime in Q4 2018.

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