Double-Sided Fingerprint Sensor for Biomechanical Anti-Spoofing
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Solution Overview
Problem
Existing fingerprint sensors are vulnerable to spoofing by latent fingerprints, necessitating additional security measures that compromise ease of use and increase false rejections.
Innovation Solution
A double-sided fingerprint sensor design utilizing a grid of parallel drive and pickup lines on both sides, capacitively coupled by insulating layers, detects surface features of two fingers simultaneously, enhancing anti-spoof protection through biomechanical angle analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional security measures such as live finger detection are implemented, then anti-spoof protection is improved, but false rejection rate increases and ease of use deteriorates
Solution Approach 1:
The patent transitions from single-sided to double-sided fingerprint sensing, adding a spatial dimension to the sensing architecture. By placing sensing elements on both sides of the sensor substrate, the system captures ridge patterns from multiple perspectives simultaneously, enabling more robust spoof detection without requiring additional security steps that would complicate user interaction
Solution Approach 2:
The double-sided sensor performs multiple functions simultaneously: it captures genuine fingerprint ridges from both sides of a finger while also detecting spoof attempts. The sensor can operate in different modes (single finger, multiple fingers, different orientations) without requiring separate security protocols, thereby maintaining ease of use while improving anti-spoof protection
2Reliability
If additional security measures such as live finger detection are implemented, then anti-spoof protection is improved, but false rejection rate increases
Solution Approach 1:
By sensing from both sides of the finger, the system obtains complementary ridge pattern information that creates a more complete biometric signature. This multi-dimensional data makes it easier to distinguish genuine fingers from spoofs, reducing false rejections while improving spoof detection accuracy
Solution Approach 2:
The system analyzes the spatial relationship and angular orientation between ridge patterns detected on opposite sides of the sensor. This feedback mechanism allows the sensor to verify the authenticity of the fingerprint by checking whether the ridge patterns from both sides are consistent with a genuine finger's biomechanical geometry, thereby reducing false rejections
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 sensor effectively differentiates genuine fingerprints from spoofed ones by utilizing the unique biomechanical angle between two fingers, significantly reducing spoofing attempts while maintaining ease of use.
Implementation Method 1
a first layer of pickup lines, a first layer of drive lines and an AC voltage source which is connected to the drive lines and causes an electric field to radiate from the drive lines to the pickup lines
Implementation Method 2
causes an electric field to radiate from the drive lines to the pickup lines
Data Source
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AI summary
A sensor has parallel upper pickup lines in an upper conductive layer, parallel lower pickup lines in a lower conductive layer, parallel drive lines oriented transversely to the upper and lower pickup lines in a middle conductive layer, a first insulating layer separating the upper pickup lines from the drive lines, and a second insulating layer opposite the first insulating layer and separating the lower pickup lines from the drive lines. Upper electrode pairs are defined at locations where an upper pickup electrode crosses a drive line, and each upper electrode pair has an impedance that is sensitive to a first object contacting or in close proximity to the upper electrode pair. Lower electrode pairs are defined at locations where a lower pickup line crosses a drive line, and each lower electrode pair has an impedance that is sensitive to a second object contacting or in close proximity to the lower electrode pair.