Embedded Fingerprint Smartcard Module With Galvanic Isolation
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Solution Overview
Problem
Current methods for integrating biometric sensors into smartcards are complex and costly, with a need for improved mechanical and electrical protection, and efficient energy management to prevent damage from external electrical charges.
Innovation Solution
A smartcard design featuring a galvanically isolated capacitive fingerprint sensor module embedded within the card, connected directly to an antenna layer for power and communication, which simplifies manufacturing and provides enhanced protection against external electrical interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fingerprint sensor module is integrated into a smartcard using mill and drill process with surface mounting, then biometric identification functionality is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent combines the fingerprint sensor module, antenna, and smartcard substrate into a single integrated structure. The sensor module is embedded directly within the smartcard layers during the lamination process, eliminating the need for separate mill-and-drill operations and surface mounting steps. This merging of components resolves the technical contradiction by achieving biometric functionality while simplifying the manufacturing process.
2Ease of operation
If a fingerprint sensor is exposed at the surface of a smartcard for user interaction, then ease of operation is improved, but mechanical protection and electrical isolation are compromised
Solution Approach 1:
The fingerprint sensor module is nested within the smartcard's multi-layer structure, specifically embedded between the substrate layers with the antenna layer. This nesting provides mechanical protection through the surrounding card layers while maintaining the sensing surface accessibility for user interaction. The galvanic isolation is achieved through the inherent electrical properties of the smartcard substrate layers that surround and protect the sensor module.
3Ease of manufacture
If the fingerprint sensor module is connected to external contacts for power and data, then ease of manufacture is improved, but vulnerability to electrical damage increases
Solution Approach 1:
The patent extracts the antenna function from traditional contact-based power and data transmission. The fingerprint sensor module communicates wirelessly through an integrated antenna embedded in the smartcard, eliminating physical contact points. This extraction of the connection interface resolves the technical contradiction by maintaining manufacturing simplicity while providing galvanic isolation that protects against electrical charge damage from external contacts.
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 solution provides robust mechanical and electrical protection for the sensor module, reduces manufacturing complexity, and ensures reliable operation without external electrodes, enabling efficient biometric identification while preventing damage from user-held electrical charges.
Implementation Method 1
Capacitive fingerprint sensing devices, built based on CMOS technology for providing the fingerprint sensing elements and auxiliary logic circuitry
Implementation Method 2
the fingerprint sensor module being configured to receive energy and communicate with a reading device via the antenna
Data Source
Figure 1~2
Figure 3
Figure 4A~4D
AI summary
A smartcard (100) comprising: a plurality of smartcard substrate layers (200); an antenna layer (208) comprising an antenna (218); a fingerprint sensor module (102) embedded in the smartcard and connected to the antenna layer, the fingerprint sensor module being configured to receive energy and communicate with a reading device via the antenna, and wherein the fingerprint sensor module is galvanically isolated from an outside of the smartcard.