Metal Case Coil Insulation for Wireless Power
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Mobile devices with metal cases often fail to receive wireless power or perform near-field communication due to the metal obstructing magnetic flux and electric power transmission.
Innovation Solution
A coil is formed along the edge of the device's metal case, with insulating portions between the coil and the metal surfaces to allow wireless power reception and near-field communication, and is integrated into the case using methods like insert injection molding, enabling efficient power transfer and data communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a metal case is used for mobile devices, then the device design and appearance are improved, but wireless power reception and near-field communication are blocked due to metal obstructing magnetic flux
Solution Approach 1:
The metal case is segmented by creating a localized opening or window at the coil position, separating the metal case into regions that can coexist with the coil structure. This allows the metal case to maintain its overall design while providing a clear path for magnetic flux at the specific location where wireless power reception and NFC functions are needed.
Solution Approach 2:
A non-magnetic material layer is introduced as an intermediary between the metal case and the coil. This intermediate layer prevents direct contact between the metal and coil, reducing eddy current losses and magnetic flux obstruction while still allowing the metal case to provide structural support and aesthetic design.
2Device complexity
If a coil is embedded in a metal case, then the device structure is simplified, but power transmission efficiency is reduced due to eddy current generation in the metal
Solution Approach 1:
A non-magnetic, electrically insulating material layer is positioned between the coil and the metal case to act as an intermediary. This layer blocks eddy current paths in the metal while allowing magnetic flux to pass through, thereby reducing energy loss without significantly increasing structural complexity.
Solution Approach 2:
The metal case is modified locally at the coil position by creating an opening or reducing metal thickness in the specific region where the coil is positioned. This localized modification reduces eddy current losses only where necessary, maintaining the overall structural integrity and aesthetic design of the metal case while improving power transmission efficiency.
3Ease of manufacture
If a coil is disposed in a metal case without insulation, then manufacturing is simplified, but magnetic flux turbulence and power loss occur
Solution Approach 1:
A composite structure is created by combining the metal case with a non-magnetic material layer at the coil position. This composite construction integrates the aesthetic and structural benefits of metal with the electromagnetic benefits of non-magnetic materials, preventing eddy currents and magnetic flux turbulence while maintaining manufacturing feasibility through processes like co-molding or adhesive bonding.
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
The solution allows mobile devices with metal cases to effectively receive wireless power and perform near-field communication without compromising the device's design, achieving high wireless charging efficiency and data transmission capabilities.
Implementation Method 1
a coil for receiving power wirelessly or performing near-field communication
Implementation Method 2
the cover part is made of an electrically non-conductive material in order to suppress loss of electric power due to eddy current generation during power transmission
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A case includes a casing region made of metal and configured to cover at least a portion of an apparatus, and a coil electrically insulated from the casing region and having a ring shape or a polygonal shape having ends separated from each other, the coil being configured to be disposed outside the apparatus.