Flexible Fingerprint Sensor Stack for Bendable Payment Cards
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Solution Overview
Problem
Conventional fingerprint recognition credit cards with silicone-based secure chips face flexibility issues, leading to damage and limited production capacity due to inflexible materials and batch production limitations.
Innovation Solution
A fingerprint sensing device comprising a flexible substrate unit, a sensing unit with capacitive electrodes, and a chip unit, where the flexible substrates are stacked with indented sides to allow for flexible connections and a roll-to-roll manufacturing process, enabling the device to pass flexibility tests and increase production capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a silicone-based secure chip is used in a credit card, then the chip provides security functionality, but the card fails flexibility tests and the chip is easily damaged due to inflexible material properties
Solution Approach 1:
The patent replaces the rigid silicone-based secure chip with a flexible organic electronic chip that can be integrated into the credit card substrate. This flexible chip maintains security functionality while enabling the card to pass flexibility tests and resist damage during normal use, directly resolving the contradiction between security reliability and operational flexibility.
Solution Approach 2:
The patent employs composite material structures combining flexible substrates with electronic sensing components. The credit card integrates an organic flexible substrate with capacitive sensing electrodes and a flexible secure chip, creating a composite structure that simultaneously achieves both security functionality and flexibility, allowing the card to bend without damage.
2Reliability
If a silicone-based secure chip is used in a credit card, then the chip provides security functionality, but the chip is easily damaged or broken due to folding or bending the card
Solution Approach 1:
The rigid silicone chip is replaced with a flexible organic electronic chip structure that can withstand folding and bending. This flexible chip design maintains structural integrity during card manipulation, preventing damage while preserving security functionality, thus resolving the contradiction between reliability and damage resistance.
Solution Approach 2:
The patent changes the material parameters from rigid silicone to flexible organic materials, fundamentally altering the mechanical properties of the secure chip. This parameter change enables the chip to withstand repeated folding and bending without damage, resolving the contradiction between maintaining security functionality and improving damage resistance.
3Ease of manufacture
If conventional semiconductor processes are used for silicone-based secure chips, then the chips can be manufactured, but batch production is limited and production capacity is constrained
Solution Approach 1:
The patent replaces conventional mechanical semiconductor fabrication processes with organic electronic manufacturing methods that enable roll-to-roll production. This substitution allows for continuous batch production of flexible secure chips, dramatically increasing production capacity while maintaining manufacturability through simplified processes.
Solution Approach 2:
The patent enables continuous roll-to-roll manufacturing of flexible organic electronic chips, replacing discrete batch processing. This continuous production method allows multiple chips to be manufactured simultaneously on flexible substrates, significantly increasing production capacity while maintaining ease of manufacture through streamlined processes.
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 flexible design enhances durability and production efficiency, allowing the fingerprint sensing device to pass credit card flexibility tests and significantly increase production capacity while reducing material costs.
Implementation Method 1
The sensing unit includes a plurality of first strip electrodes, a plurality of second strip electrodes... The first strip electrodes are disposed on the first surface and are disposed between the first flexible substrate and the double-sided substrate
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
A fingerprint sensing device (1) includes a double-sided substrate (22) between first and second flexible substrate (21, 23), and first strip electrodes (31) formed on the double-sided substrate (23) and contacting first electroconductive pads (33) disposed on the first flexible substrate (21) and downwardly contacting connecting pads (34) on a second flexible substrate (23). Second strip electrodes (32) are formed on the double-sided substrate (22) and downwardly contacting second electroconductive pads (35) disposed on the second substrate (23). The connecting pads (34) and the second electroconductive pads (35) are electrically connected to a chip unit (7). A method of making the same is also disclosed.