Metal-Layer Chip Card Body With Opposing Angled Slots for Shear Resistance
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Solution Overview
Problem
Card bodies for chip cards with external metal layers, also known as metal-face cards, suffer from reduced mechanical stability due to slots designed perpendicular to the surface, which can cause damage and short-circuit currents, and are prone to shear forces.
Innovation Solution
The card body design incorporates two metal layers with a non-conductive middle layer, featuring angled slots that intersect at non-90° angles, preventing shearing movements by overlapping metal layer regions and reducing penetration depth, thereby enhancing structural stability and minimizing adhesive leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If slots are designed perpendicular to the metal layer surface, then short-circuit currents are prevented, but mechanical stability is reduced
Solution Approach 1:
The slot is designed with an asymmetric angle relative to the metal layer surface, entering at an angle between 10° and 80° rather than perpendicular. This asymmetric configuration prevents short-circuit currents by maintaining electrical isolation while reducing the slot's impact on mechanical strength by distributing stress more favorably across the metal layer.
2Reliability
If slots extend deeply into the metal layer, then electrical isolation is improved, but penetration depth increases causing visual and structural issues
Solution Approach 1:
The slot geometry is optimized by changing the entry angle parameter to between 10° and 80° relative to the surface normal. This parameter change achieves adequate electrical isolation with reduced penetration depth, improving both visual appearance and mechanical properties while maintaining the necessary electrical separation between conductive elements.
Data Source
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AI summary
The invention relates to a card body (10) for a chip card (20), having two metal layers (16, 18), between which a non-conductive central layer (17) is arranged, wherein a module opening (14) for receive a chip module (21) is already produced in one metal layer (16) and in the aforementioned metal layer (17) or can still be produced in a module opening zone, and two slots (15), one of which extends from the peripheral surface (13) of the card body (10) to the module opening (14) or to the module opening zone in a metal layer (16, 17) and severs each of the metal layers (16, 17) at a respective height. The entry angle (a) of the two slots (15) into the metal layer (16) does not equal 90° relative to the surface (11) of the metal layer (16) in each case, and the two slots (15) have opposite inclinations relative to a surface normal of the surface (11) of the metal layer (16).