Layered Metal Card Structure for Reliable RF Communication
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Solution Overview
Problem
Conventional metal cards face limitations in RF communication due to their metal material characteristics, which hinder the operation of antennas and restrict the use of RF functions, and they also struggle with printing patterns and characters on their surface.
Innovation Solution
A method for manufacturing metal cards that involves heat-treating a SUS metal sheet to enhance its strength, forming a processed plastic layer on the metal sheet using CNC machining, and laminating it with an antenna coil and insulating layers to create a COB insertion area, allowing direct connection of the antenna coil to the COB without contact with the metal sheet, thereby improving wireless communication sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a metal sheet is used to make a card, then the card has metallic luster and high-level outer appearance, but the metal material characteristics hinder antenna operation and prevent RF communication
Solution Approach 1:
The card is divided into distinct layers: a metal sheet layer for aesthetic appearance and a plastic layer for functional components. This segmentation allows the metal and antenna to be spatially separated, enabling RF communication while maintaining metallic luster.
Solution Approach 2:
A plastic layer is introduced as an intermediary material between the metal sheet and the antenna coil. This intermediate layer electrically isolates the antenna from the conductive metal surface, preventing interference and enabling reliable RF communication while the metal sheet remains visible for aesthetic purposes.
2Weight of moving object
If the metal card is made of a thin film type metal sheet or thin layer coated with metal powder, then the card is lightweight, but it is difficult to print patterns and characters on the surface
Solution Approach 1:
The card uses a composite structure combining a thin metal sheet layer (for light weight and metallic appearance) with a plastic layer (for printing capability). This composite material approach allows both lightweight properties and ease of printing patterns and characters on the plastic surface.
3Weight of moving object
If the metal card is made of relatively lightweight materials, then the card has reduced weight, but no weight is transferred from the metal to the metal card
Solution Approach 1:
The card structure is segmented into a thin metal sheet layer and a plastic layer. The metal sheet provides aesthetic metallic appearance while the plastic layer provides structural integrity and functional support, allowing lightweight construction without sacrificing necessary strength.
Solution Approach 2:
The composite structure of thin metal sheet combined with plastic material achieves optimal balance between weight and strength. The plastic layer compensates for the reduced weight of the thin metal sheet, providing the necessary structural support and enabling functional components to be mounted.
4Reliability
If metals are disposed on the center of the card to prevent antenna coil from contacting, then the antenna can operate, but the whole outer appearance looks bad and metal texture cannot be expressed
Solution Approach 1:
The solution moves from a two-dimensional planar arrangement where metal and antenna must compete for space to a three-dimensional layered structure. The metal sheet forms the visible front surface while the antenna coil is positioned in a separate layer behind it, allowing both full metal coverage for aesthetic purposes and full antenna functionality without visual compromise.
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
This method enhances the operational efficiency of the chip, improves wireless communication sensitivity, and maintains the metal material's characteristics while preventing interference between the metal and antenna coil, enabling effective contactless communication.
Implementation Method 1
heat treating the metal sheet made of a SUS material to improve strength and tension thereof
Implementation Method 2
at the time of contactless communication to a reader it is hard to operate antennas because of the characteristics of the metal
Data Source
AI summary
Provided is a method for manufacturing a metal card which is capable of allowing metal card antennas to have no interference with a metal sheet by including a processed plastic layer formed on the metal sheet, and an insulating sheet. The metal card is capable of improving sensitivity of antenna coil, thereby solving an existing problem of the difficulties in performing RF communication because of material characteristics of a metal layer.