Multi-coil Module with Magnetic Sheet for NFC and Charging
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Solution Overview
Problem
Near field communication systems using electromagnetic induction often fail to establish effective communication between antennas with significantly different coil sizes, leading to inadequate magnetic flux transfer and potential heat generation due to eddy currents when multiple coils are integrated in a small space.
Innovation Solution
A multi-coil module design where the antenna coil in the mobile device has a spiral shape with varying pitch and line widths, with the innermost pattern overlaid with the non-contact charging coil, and a magnetic sheet configuration that accommodates the non-contact charging module, reducing eddy current generation and optimizing magnetic flux transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the antenna coil size is reduced to match the IC tag coil size, then near field communication can be established, but the magnetic field density becomes insufficient for effective communication
Solution Approach 1:
The patent applies local quality by creating different regions within the antenna coil structure. The innermost pattern has a smaller diameter than outer patterns, creating a concentrated magnetic field region that matches the IC tag coil size for reliable communication, while outer patterns provide additional magnetic field density. This spatial variation in coil geometry allows simultaneous optimization of both communication reliability and magnetic field strength.
2Volume of moving object
If multiple coil modules are integrated in a small space, then device downsizing is achieved, but eddy currents are generated causing heat generation
Solution Approach 1:
The patent introduces a magnetic sheet as an intermediary component between the antenna coil and the non-contact charging coil. This magnetic sheet serves as a mediator that guides and concentrates magnetic flux, improving coupling efficiency between the overlaid coils while reducing eddy current losses. By placing the magnetic sheet in the intermediate position, the patent achieves compact integration of multiple coil modules while mitigating the harmful thermal effects of eddy currents.
3Length of stationary object
If the pitch and line width of the antenna pattern are increased, then the inner diameter is reduced, but the magnetic flux transfer efficiency decreases
Solution Approach 1:
The patent segments the antenna coil into multiple patterns with different geometries. The innermost pattern has a smaller diameter and is specifically designed to match the IC tag coil dimensions for effective magnetic flux transfer, while outer patterns have larger diameters with different pitch and line width configurations. This segmentation allows each pattern to optimize for its specific function, maintaining magnetic flux transfer efficiency while achieving the required inner diameter reduction.
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
Ensures efficient inductive coupling and reduced heat generation, enabling effective communication and charging while minimizing the module's size and preventing thermal shock to neighboring components.
Implementation Method 1
Near field communication systems using electromagnetic induction often fail to establish effective communication between antennas with significantly different coil sizes
Implementation Method 2
These methods all utilize electromagnetic induction or magnetic resonance occurred between a primary coil and a secondary coil
Implementation Method 3
a magnetic sheet configuration that accommodates the non-contact charging module, reducing eddy current generation and optimizing magnetic flux transfer
Implementation Method 4
potential heat generation due to eddy currents when multiple coils are integrated in a small space
Data Source
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AI summary
The loss is reduced even when loop coils of a multi-coil module are overlaid with each other. The multi-coil module includes a first coil module (2), having a first magnetic sheet (4) and a first loop coil (5) provided on the first magnetic sheet (4) and wound in a planar shape, and a second coil module (3), having a second magnetic sheet (6) and a second loop coil (7) provided on the second magnetic sheet (6) and wound in a planar shape. The first coil module (2) and the second coil module (3) are stacked on each other, and at least an innermost coil pattern of the first loop coil (5) and the second loop coil (7) are overlaid with each other. The line width of the innermost coil pattern t of the first loop coil overlaid with the second loop coil is 1 mm or less.