Smart Card Biometric Sensor Coverlay for Durable Fingerprint Detection
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Solution Overview
Problem
Biometric sensors in smart cards are prone to deterioration due to factors like humidity, perspiration, mechanical abrasion, UV aging, and temperature, which affect the fingerprint detection zone, and existing protective materials either fail to provide adequate protection or are not compatible with manufacturing processes.
Innovation Solution
A biometric sensor module with a dielectric support and a protective layer made of photoimageable epoxy-acrylate resin is integrated, which is resistant to mechanical and chemical wear and compatible with industrial manufacturing processes, including roll-to-roll processing and photolithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective layer is applied to the detection zone, then resistance to humidity, perspiration, mechanical abrasion, UV aging, and temperature is improved, but the material must not interfere with fingerprint detection and must be compatible with manufacturing processes
Solution Approach 1:
The patent applies a protective layer with specific optical parameters (transparency to specific wavelengths) that allows fingerprint detection to function while providing environmental protection. The layer's optical properties are carefully selected to permit the biometric sensor to detect ridges and valleys through the coating without interference, thus resolving the contradiction between protection and detection compatibility
Solution Approach 2:
The patent uses composite material structures including the protective layer in combination with the biometric sensor and circuit board, creating a multi-layer system where each layer performs its specific function. The protective layer is designed as part of a composite structure that integrates protection, detection, and manufacturing compatibility requirements
2Strength
If a protective layer is applied to the detection zone, then mechanical and chemical resistance is improved, but the material must not interfere with fingerprint detection
Solution Approach 1:
The protective layer's optical parameters are specifically selected to be transparent to the wavelengths used by the biometric sensor for fingerprint detection. This parameter optimization ensures that the layer provides mechanical and chemical protection while maintaining detection precision, allowing the sensor to accurately detect fingerprint ridges and valleys through the protective coating
3Ease of manufacture
If photoimageable epoxy-acrylate resin is used for the protective layer, then ease of integration into industrial processes is improved, but the material properties must still provide superior hardness and abrasion resistance
Solution Approach 1:
The patent specifies epoxy-acrylate resin with carefully controlled compositional parameters and curing conditions that achieve both ease of manufacturing (photoimageability for industrial processing) and superior mechanical properties (hardness and abrasion resistance). The resin formulation and curing parameters are optimized to simultaneously satisfy both manufacturing ease and performance requirements
Solution Approach 2:
The patent replaces traditional mechanical curing methods with photoimageable (UV or other radiation) curing for the protective layer. This substitution enables integration into roll-to-roll and other industrial manufacturing processes while maintaining or improving the mechanical properties of the protective layer, as the photopolymerization process provides controlled curing without mechanical stress
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 protective layer effectively shields the biometric sensor from environmental factors while being easily integrated into smart card manufacturing, ensuring high yield and durability of the fingerprint detection zone.
Implementation Method 1
whose physicochemical properties, particularly in terms of hardness and abrasion resistance, are superior after UV or thermal curing
Data Source
Figure 1~2
Figure 3a~3f2
Figure 3g~6
AI summary
The invention relates to a method for manufacturing a biometric sensor module (4) for a smart card, comprising steps, during which a dielectric support (101) having a front face and a rear face is provided, the front face being coated with an electrically conductive layer, in which a bezel (5) is formed, at least one conductive via (104) being produced in the thickness of the support (101) for electrically connecting the bezel (5) to the rear face. A protective layer (108) is produced in the front face, covering a protective area, located inside the bezel (5), and a biometric sensor (300) is attached for the detection of fingerprints at the rear face, wherein a detection zone covered by the sensor (300) on the rear face is placed facing the protective area.