Smart Card Asymmetric Transparent Edge Resists Corner Delamination

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Solution Overview

Problem

Existing smart cards with transparent frames face challenges in maintaining impact resistance when increasing the transparent area, particularly in corners, leading to delamination and failure in compliance with standards like MasterCard CQM 2016 TM-417 and ANSI 322 2015 § 5.19, 6.1, 6.6.

Innovation Solution

A security document with a modified transparent frame structure featuring an asymmetrical curved boundary line between a cutout in the opaque coupon and a bulging transparent corner, enhancing the corner's resistance to impact tests while allowing for larger transparent areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the transparent frame area is increased to accommodate security motifs, then the card's security and visual differentiation are improved, but the card's impact resistance deteriorates

Engineering Contradiction:
ImprovesecurityVSAvoidimpact resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies asymmetry by creating a bulge in only one corner of the transparent frame rather than uniformly increasing transparency across all corners. This asymmetric design allows the security motif to be placed in a single corner while maintaining structural integrity in other areas. The bulge is positioned to maximize security functionality while minimizing impact on overall card strength.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent implements local quality by concentrating the transparent frame enhancement in a specific corner region where the security motif is required, rather than uniformly increasing transparency across the entire frame. This localized approach allows the security functionality to be improved precisely where needed while preserving the impact resistance of the overall card structure.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If the transparent frame area is increased, then the card's visual differentiation and anti-counterfeiting capability are improved, but the card's physical resistance to impact tests deteriorates

Engineering Contradiction:
Improvevisual differentiationVSAvoidphysical resistance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The asymmetric corner bulge design enables visual differentiation and anti-counterfeiting features to be implemented in a localized manner. The irregular shape of the bulge creates unique visual characteristics that enhance security while the asymmetric distribution of material maintains structural balance and resistance to impact forces.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent segments the transparent frame modification into a discrete corner bulge rather than a uniform expansion. This segmentation allows the security-enhancing transparent area to be separated from the structural core of the card, enabling visual differentiation without compromising the overall physical resistance of the card body.

Inventive Principle:
Principle #1Segmentation

3Area of stationary object

If the corner transparent area is enlarged, then the card's security motif accommodation capability is improved, but the card's compliance with impact test standards deteriorates

Engineering Contradiction:
Improvetransparent corner surface areaVSAvoidimpact test compliance
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The asymmetric design of the corner bulge with its irregular boundary line creates a unique geometric profile that accommodates security motifs while maintaining structural integrity. The non-uniform shape distributes stress differently compared to a symmetric expansion, helping the card meet impact test requirements despite the increased transparent area.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent employs curvature in the boundary line of the corner bulge, using rounded transitions instead of sharp angles. This curvature helps distribute impact forces more evenly across the modified corner region, preventing stress concentration that would lead to delamination and maintaining compliance with impact test standards.

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Reliability

If the transparent frame is modified to have larger corner areas, then the card's security features are enhanced, but the card's resistance to delamination deteriorates

Engineering Contradiction:
Improvesecurity featuresVSAvoidresistance to delamination
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The asymmetric corner bulge design creates an irregular interface between the transparent frame and the underlying structure. This asymmetric geometry, with its curved boundary line, increases the surface area for adhesion in a non-uniform pattern that enhances security features while maintaining delamination resistance through distributed bonding areas.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The curved boundary line of the corner bulge creates smooth transitions and rounded interfaces between different card layers. This curvature eliminates sharp corners that would be stress concentration points, thereby preventing delamination while still providing the increased transparent area needed for security features.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP4272120B1Smart card with enlarged transparent edge
Publication Date: 2025.08.06 IMPRIMERIE NAT
  • EP4272120B1 patent drawingFigure 1~2
  • EP4272120B1 patent drawingFigure 3~4
  • EP4272120B1 patent drawingFigure 5~6

AI summary

The invention is directed to a security document comprising a coupon (30) in the form of a multi-layered complex consisting mainly of an opaque zone and surrounded by a transparent border (4), the security document being characterised in that the coupon (30) comprises a die-cut (21) in at least one of the corners thereof, in that the transparent border (4) comprises, at said die-cut (21), a broadened zone (22) matching said die-cut (21), and in that the boundary (23) between said die-cut (21) and said broadened zone (22) has a curved shape that is dissymmetric relative to the bisector (B) of the angle of the corner corresponding to the broadened zone (22) of the transparent border (4).