RFID Tag Magnetic Core for Metal Articles
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Solution Overview
Problem
Conventional RFID tags struggle to accurately read and write information on articles containing metal due to electromagnetic noise interference and the requirement for additional space to form a magnetic flux leakage path or use of amorphous magnetic sheets, making them bulky and difficult to miniaturize.
Innovation Solution
An electromagnetic inductive RFID tag with a U-shaped or C-shaped magnetic core member that forms a closed magnetic path with the reader, allowing for communication without significant influence from the metal, even when embedded, using a magnetic core member with end faces that alternate as entering and emitting faces for the magnetic flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional RFID tags are used on metal-containing articles, then reading capability is affected by electromagnetic noise, but adding magnetic flux leakage paths or amorphous magnetic sheets increases device size
Solution Approach 1:
The patent combines the antenna coil and magnetic core member into an integrated electromagnetic inductive RFID tag structure. The magnetic core member is positioned within the antenna coil, merging the electromagnetic induction components into a compact unified device that eliminates the need for separate magnetic flux leakage paths or amorphous magnetic sheets.
Solution Approach 2:
The magnetic core member acts as an intermediary between the antenna coil and the metal-containing article. It guides and concentrates the magnetic flux, enabling reliable communication by mediating the electromagnetic interaction between the RFID tag and the metal article without requiring additional space for flux leakage paths.
2Measurement precision
If electromagnetic inductive RFID tags are embedded in metal articles, then reading accuracy is improved, but space requirements increase due to magnetic flux path needs
Solution Approach 1:
The magnetic core member is nested within the antenna coil structure, and the entire RFID tag is embedded within the metal article. This nested configuration allows the magnetic core to be positioned centrally within the antenna's magnetic field, maximizing reading accuracy while minimizing the overall embedding space required.
Solution Approach 2:
The patent changes the operational parameters by using electromagnetic induction at a frequency that allows the magnetic core member to effectively guide magnetic flux through the metal article. This parameter optimization enables accurate reading with minimal embedding space, as the magnetic induction process is tuned to work efficiently within the constrained embedded geometry.
3Reliability
If low frequency band (≤135 kHz) is used to leak magnetic field through metal gaps, then reading becomes possible, but susceptibility to electromagnetic noise increases
Solution Approach 1:
The patent converts the harmful effect of metal presence (which blocks electromagnetic fields) into a beneficial effect by using the metal article itself as part of the magnetic flux path. The magnetic core member guides the magnetic flux through the metal, and the metal's conductivity and magnetic properties are utilized to enhance rather than hinder the reading capability, while operating at frequencies less susceptible to noise.
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 accurate reading and writing of information on metal-containing articles with minimal space requirements, reducing the impact of electromagnetic noise and allowing for miniaturization of the RFID tag, while maintaining high reading accuracy even when embedded in metal.
Implementation Method 1
an electromagnetic inductive RFID tag (10) to be used along with an article containing a metal
Implementation Method 2
a magnetic core member (13) which guides a magnetic flux
Implementation Method 3
an antenna coil (12) connected to the IC chip (11)
Data Source
Figure 1A~1B
Figure 2~3E
Figure 4~5
AI summary
[Object] The present invention provides an electromagnetic inductive RFID tag to be used along with an article containing a metal, and an apparatus for accessing the RFID tag. [Constitution] An electromagnetic inductive RFID tag in the present invention comprises a magnetic core member having two ends, each of which has an end face, an antenna coil wound on the magnetic core member, and an IC chip connected to the antenna coil, in which, with respect to a direction of a magnetic flux entering an one side of the end face, a direction of a magnetic flux emitting from the other side of the end face is substantially at an angle of 180 degrees. By such characteristics, information can be read with a high reading accuracy without being influenced by a surrounding metal. An apparatus accessesing the RFID tag comprises a magnetic core member having two ends, each of which has an end face, an antenna coil wound on the magnetic core member, and a control unit connected to the antenna coil, in which, with respect to a direction of the magnetic flux entering an one side of the end face, a direction of a magnetic flux emitting from the other side of the end face is substantially at an angle of 180 degrees. It is preferable that such an access apparatus is used in combination with the RFID tag in the present invention.