Wearable NFC Antenna Structure for Wireless Charger Object Detection
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Solution Overview
Problem
Wearable devices, such as chip cards, are susceptible to damage during wireless charging due to the inability of standard wireless energy chargers to detect and prevent energy absorption by conductive materials not designed for charging, leading to overheating.
Innovation Solution
Incorporating an electrically conductive structure, such as a metal surface or resonant circuit, into wearable devices to trigger foreign object detection in wireless energy chargers, utilizing existing detection mechanisms to prevent charging when a wearable is present.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard wireless energy chargers are used without additional detection mechanisms, then charging simplicity and device compatibility are maintained, but wearable devices may be damaged due to undetected energy absorption
Solution Approach 1:
The wearable device itself generates the detection signal through its existing NFC/RFID antenna and chip, which are activated by the charger's electromagnetic field. The device's own communication components serve the dual purpose of both wireless communication and foreign object detection, eliminating the need for separate detection hardware in the charger.
Solution Approach 2:
The NFC/RFID antenna and chip in the wearable device perform multiple functions: contactless communication for payment and identification, and foreign object detection for safety during wireless charging. This multi-functionality resolves the contradiction by using existing components for dual purposes rather than adding dedicated detection hardware.
2Reliability
If NFC/RFID detection is implemented in the smartphone to warn users, then wearable device damage can be prevented in some cases, but the solution requires additional hardware and software modifications in both the smartphone and charger
Solution Approach 1:
The wearable device autonomously triggers the foreign object detection by presenting its NFC/RFID interface to the charger's electromagnetic field. The detection and safety mechanism is embedded in the wearable device itself, eliminating the need for complex inter-communication between smartphone, charger, and wearable device.
3Reliability
If a metal structure is integrated into the wearable device to trigger foreign object detection, then charger detection capability is improved, but the wearable device structure becomes more complex
Solution Approach 1:
The existing NFC/RFID antenna, which is already present in the wearable device for communication purposes, is utilized to trigger the foreign object detection. This eliminates the need for additional metal structures while maintaining detection accuracy, as the antenna's conductive properties are sufficient for the charger's detection algorithms.
Solution Approach 2:
The communication function and detection function are merged into a single component - the NFC/RFID antenna. This antenna serves both to enable contactless communication and to trigger the foreign object detection in the charger, thereby reducing overall device complexity while maintaining both functionalities.
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
Effectively prevents damage to wearable devices by ensuring the charger detects and halts charging when a wearable is present, maintaining device integrity and safety.
Implementation Method 1
The wireless energy charger 106 is set up to charge the electronic device 202 wirelessly by means of electromagnetic induction in accordance with a wireless charging standard
Implementation Method 2
The chip card 104 made then be compelled to take up energy and convert it to heat, which may damage the chip card
Data Source
AI summary
A wearable device including an antenna structure, a chip having a receiver which is electrically coupled to the antenna structure and is configured to receive radio signals by means of the antenna structure, and a trigger device which is arranged in or on the wearable device, which device comprises electrically conductive material and which is configured to trigger foreign object detection in a wireless energy charger in accordance with a wireless charging standard for wirelessly charging an electronic device by means of taking up load from radio waves emitted by the wireless energy charger.