Segmented Conductive Back Cover for Wireless Power Transfer
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Solution Overview
Problem
Metallic back covers in electronic devices pose challenges for wireless power transfer due to their ability to absorb electromagnetic radiation, making it difficult to efficiently transmit and receive energy without physical conductors.
Innovation Solution
The use of a segmented housing with electrically conductive segments and a coil of conductive material arranged between these segments, which induces eddy currents and couples with an externally generated magnetic field to generate electrical current for power transfer, while also incorporating ferrite material for magnetic shielding to protect electronic components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metallic back cover is used in an electronic device, then the aesthetic appearance and structural strength are improved, but the wireless power transfer efficiency deteriorates due to electromagnetic radiation absorption
Solution Approach 1:
The back cover is divided into multiple segments (first back cover segment, second back cover segment, third back cover segment) separated by gaps. This segmentation prevents the formation of continuous eddy currents in the metallic back cover, reducing electromagnetic radiation absorption and improving wireless power transfer efficiency while maintaining the aesthetic appearance and structural strength of a metallic back cover
Solution Approach 2:
Ferrite sheets are introduced as intermediary materials positioned between the wireless power receiver coil and the metallic back cover. These ferrite sheets serve as magnetic shielding that guides and concentrates the magnetic flux through the coil, improving coupling efficiency and reducing the detrimental effects of the metallic back cover on wireless power transfer
2Ease of manufacture
If a continuous metallic back cover is used, then the manufacturing simplicity is improved, but the wireless power receiver performance deteriorates due to eddy current interference
Solution Approach 1:
The back cover is segmented into multiple pieces with gaps between them, which disrupts the eddy current paths. This segmentation can be achieved through standard manufacturing processes by assembling multiple cover pieces, maintaining ease of manufacture while significantly improving wireless power receiver performance by reducing eddy current interference
Solution Approach 2:
The back cover assembly becomes a composite structure combining metallic segments (for aesthetics and strength) with ferrite materials (for magnetic shielding and flux guidance). This composite approach leverages the advantages of different materials to achieve both manufacturing feasibility and improved wireless power transfer performance
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables efficient wireless power transfer by directly coupling the magnetic field to the conductive coil and using eddy currents to provide combined current to electronic circuits, effectively overcoming the absorption issues caused by metallic back covers and ensuring proper operation of electronic components.
Implementation Method 1
a power receiving element comprising the coil of electrically conductive material and at least one of the first electrically conductive segment or the second electrically conductive segment. The power receiving element may be configured to couple to an externally generated magnetic field to wirelessly receive power
Implementation Method 2
The coil of electrically conductive material may be arranged substantially only along a spacing between the first and second electrically conductive segments
Implementation Method 3
The apparatus may further include ferrite material disposed between at least a portion of the coil of electrically conductive material and electronic components of the electronic device. The ferrite material may be arranged relative to the electronic components of the electronic device to shield the electronic components from magnetic fields including the externally generated magnetic field that can arise during wireless power transfer
Data Source
Figure 1~3
Figure 4A~4B
Figure 5A~5C
AI summary
An apparatus for wireless power transfer is disclosed. The apparatus may include a portion of a housing of an electronic device. The portion of the housing may include at least a first electrically conductive segment and a second electrically conductive segment spaced apart from the first electrically conductive segment. A coil of electrically conductive material may be arranged relative to the first and second electrically conductive segments. A power receiving element may include the coil of electrically conductive material and either or both the first and second electrically conductive segments.