Filling Slits in Metallic Smartcards with Polymer Resin
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Solution Overview
Problem
Existing metallic smartcards face challenges in maintaining structural integrity and preventing delamination of slits filled with electrically insulating materials, as previous filler materials tend to separate when the card is flexed, hindering contactless communication.
Innovation Solution
Applying an electrically insulating polymer resin, such as a UV and/or heat-curable urethane resin, to fill the slits in the metal layer, which provides high bond strength and resistance to delamination upon flexing, using methods like plasma pretreatment and curing with UV or heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a slit is provided in the metal layer to form a coupling frame for contactless communication, then contactless communication is enabled, but the structural strength and rigidity of the metal layer are compromised
Solution Approach 1:
An electrically insulating filler material is introduced as an intermediary substance to fill the slit in the metal layer. This filler material serves dual purposes: it maintains the structural integrity and rigidity of the card body while allowing the metal layer to form a coupling frame for contactless communication. The filler acts as a mediator that bridges the structural gap created by the slit.
2Strength
If the slit is filled with electrically insulating filler material to maintain structural strength, then structural integrity is maintained, but the filler material separates from the metal layer when the card is flexed
Solution Approach 1:
The patent modifies the physical and chemical parameters of the filler material by selecting a material with appropriate elasticity and adhesion properties. The filler material is chosen to have elastic properties that allow it to deform with the metal layer during flexing, and adhesive properties that ensure strong bonding to both the metal layer and the card body, preventing separation under mechanical stress.
Solution Approach 2:
The solution employs a composite material approach by using an electrically insulating filler material that combines multiple properties: electrical insulation to maintain signal integrity, elasticity to accommodate flexing, and adhesion to bond with the metal layer. This composite material resolves the contradiction by integrating multiple functional requirements into a single material system.
3Adaptability or versatility
If a metal layer is used for aesthetics and premium feel, then product appeal is enhanced, but the metal layer hinders or prevents contactless communication between the chip and reader
Solution Approach 1:
The metal layer is segmented by providing one or more slits that discontinuously divide the metal layer, allowing it to form a coupling frame around the chip. This segmentation enables the metal layer to simultaneously maintain its aesthetic appearance and premium feel while creating pathways for electromagnetic signals to pass through, thus enabling contactless communication.
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 method effectively maintains structural strength and ensures reliable contactless communication by preventing delamination of the resin from the metal layer, even after repeated flexing of the smartcard.
Implementation Method 1
UV and/or heat-curable urethane resin
Implementation Method 2
UV and/or heat-curable urethane resin
Implementation Method 3
plasma pretreatment
Data Source
AI summary
A method for filling a through slit in a metal layer for use in a metallic smartcard by providing a metal sheet having at least one through slit extending through the thickness of the metal sheet, applying a polymer resin to the metal sheet so as to substantially fill the slit(s), and curing the resin. A coupling frame for a smartcard, and a smartcard are also provided.