RFID Screw for Eyeglass Frames Using Ferrite Rod Antenna
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Solution Overview
Problem
Existing RFID technologies are not suitable for use on eyeglass frames, particularly in terms of miniaturization and integration with screws, which limits their application in inventory management, theft protection, and real-time sales updates in the retail sector.
Innovation Solution
A custom-designed RFID screw with a small loop antenna coil that resonates at 915 MHz, utilizing near field magnetic induction coupling to activate a passive tag, integrated into a screw for eyeglass frames, allowing for accurate inventory tracking and theft prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional RFID tags are used for inventory tracking, then identification capability is achieved, but the tags are too large to be integrated into eyeglass frame screws
Solution Approach 1:
The RFID tag is nested inside the screw head cavity, with the antenna coil wrapped around a ferrite rod that fits within the screw structure. This nesting approach allows the RFID functionality to be integrated into the existing screw without requiring additional space or modifying the screw's external dimensions.
Solution Approach 2:
The RFID tag transitions from a planar two-dimensional structure to a three-dimensional configuration by wrapping the antenna coil around a ferrite rod. This dimensional transformation enables compact packaging of the RFID components within the limited space of the screw head while maintaining electromagnetic functionality.
2Volume of moving object
If a passive RFID tag is used to reduce size and cost, then miniaturization is achieved, but the tag requires strong illumination power that causes interference and radiation exposure
Solution Approach 1:
A ferrite rod is introduced as an intermediary component between the antenna coil and the RFID chip. The ferrite rod concentrates and guides the magnetic field, improving coupling efficiency and reducing the illumination power required from the reader. This mediator enables reliable passive tag operation with lower power levels, reducing radiation interference and exposure concerns.
3Speed
If the RFID antenna is made larger to improve signal transmission, then reading range is increased, but the antenna cannot fit within the screw head space
Solution Approach 1:
The ferrite rod acts as a resonant element that concentrates magnetic flux and enhances the magnetic field strength at the antenna resonance frequency. This resonant effect compensates for the small physical size of the coil, achieving adequate signal transmission efficiency and reading range despite the constrained antenna dimensions within the screw head.
4Adaptability or versatility
If a custom RFID screw is designed and manufactured, then integration with eyeglass frames is achieved, but manufacturing complexity increases
Solution Approach 1:
The RFID tag, antenna coil, ferrite rod, and screw components are merged into a single integrated assembly. The RFID components are pre-assembled within the screw head cavity, and the entire unit is manufactured as one piece using existing screw manufacturing processes. This merging eliminates the need for separate assembly steps and modifies existing production workflows rather than requiring entirely new manufacturing methods.
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
Enables efficient inventory management, real-time sales updates, and improved theft protection by streamlining the inventory process and providing accurate tracking of eyeglass frames from manufacturing to retail, without requiring significant changes to existing frame production methods.
Implementation Method 1
utilizing near field magnetic induction coupling to activate a passive tag
Implementation Method 2
a small loop antenna coil that resonates at 915 MHz
Data Source
AI summary
The RFID tag of the embodiments of the present invention includes an integrated circuit for storing and processing information that modulates and demodulates radio-frequency (RF) signals, apparatus of collecting the AC power signal from an incident reader, and an antenna for receiving and transmitting the signal. The RFID tag information is stored in a non-volatile memory. The RFID tag includes either fixed or programmable logic for processing the transmission and sensor data, respectively.