NFC Ring Eddy Current Suppression via Segmented Metal Design
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Solution Overview
Problem
Current NFC rings face challenges in achieving robust and high-performance designs due to the damping effect of metal bodies, which reduces magnetic field strength and load modulation amplitude, and are prone to damage from mechanical stress.
Innovation Solution
Incorporating small isolation gaps in metal rings to prevent eddy currents and using stacked edged metal rings with isolation layers to maintain robustness and aesthetic appeal, while avoiding ferrite and using metals like silver, gold, or titanium for the NFC ring structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a solid metal ring is used for NFC ring, then robustness and aesthetic appeal are improved, but magnetic field strength and load modulation amplitude are reduced due to eddy currents
Solution Approach 1:
The metal ring is segmented by introducing gaps that divide the continuous conductive path into separate sections. This segmentation prevents eddy currents from forming complete loops, thereby reducing energy loss while maintaining the structural robustness and aesthetic appeal of the metal ring.
Solution Approach 2:
Conductive material is extracted or removed from specific portions of the ring to create gaps. This extraction eliminates the harmful eddy current paths while preserving the overall metal ring structure, achieving both robustness and acceptable NFC performance.
2Loss of energy
If gaps are introduced in metal ring to prevent eddy currents, then magnetic field strength is improved, but structural robustness and aesthetic appeal are reduced
Solution Approach 1:
The gaps are designed with specific local characteristics - they are positioned and sized to be minimal in critical structural areas while sufficient to break eddy current paths. This local optimization maintains overall robustness while achieving the necessary magnetic field performance.
3Manufacturing precision
If standard flex print PCB is used for antenna, then manufacturing precision and cost are improved, but mechanical robustness is reduced
Solution Approach 1:
The antenna structure uses a composite design combining flex print PCB for precise antenna parameters with additional protective layers or alternative substrate materials that enhance mechanical robustness. This composite approach leverages the strengths of different materials to achieve both manufacturing precision and mechanical strength.
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 maintains near-field communication performance comparable to standard NFC rings while enhancing robustness and aesthetic appeal, with minimal impact on magnetic field strength and load modulation amplitude, and provides mechanical protection for the chip and antenna.
Implementation Method 1
the chip, using the antenna, is configured to provide a near field communication with an external device
Implementation Method 2
Inclusion of small isolation gaps in the metal ring prevents formation of eddy currents
Data Source
AI summary
A near field communication ring configured to be worn by a user is provided. The NFC ring may include at least one metal ring having a gap, a chip, and an antenna, wherein the chip and the antenna may be fixed to the at least one metal ring having a gap, and wherein the chip, using the antenna, is configured to provide a near field communication with an external device.