Fingerprint Sensor Shield Layers for Noise Reduction
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Solution Overview
Problem
Current fingerprint sensors face challenges in achieving high resolution and sensitivity, leading to degraded fingerprint image quality due to direct contact of fingers with driving and sensing electrodes, which results in noise generation and image degradation.
Innovation Solution
The implementation of shield layers made of transparent conductive metal oxide on extensions of sensing and driving electrodes, along with specific wiring configurations and electrode patterns, reduces noise interference and maintains image quality by spacing apart the contact points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If shield layers are added to reduce noise interference, then fingerprint image quality is improved, but device complexity increases
Solution Approach 1:
The patent introduces shield layers as intermediary elements between the finger contact surface and the sensing electrodes. These shield layers act as mediators that block noise interference from reaching the sensing electrodes, thereby improving fingerprint image quality without requiring fundamental changes to the sensor architecture
Solution Approach 2:
The patent segments the electrode structure by separating the sensing function from the noise-prone contact region. The shield layers divide the tracer regions into protected zones, isolating the sensitive sensing electrodes from direct noise exposure while maintaining the overall sensor functionality
2Measurement precision
If high resolution and sensitivity are achieved, then fingerprint authentication accuracy is improved, but noise generation increases leading to image degradation
Solution Approach 1:
The patent converts the harmful noise generated by direct finger contact into a manageable issue by introducing shield layers. These shields transform the noise problem into a localized interference issue that can be blocked, allowing high-resolution sensing to proceed without degradation from noise
Solution Approach 2:
The patent applies different properties to different regions: the active sensing regions maintain high sensitivity and resolution, while the tracer regions are equipped with shield layers for noise protection. This local differentiation allows high authentication accuracy in the active region while managing noise in the tracer regions
Data Source
AI summary
A fingerprint sensor and a method of manufacturing the same are provided. The fingerprint sensor includes an active region including driving electrodes and sensing electrodes crossing the driving electrodes, tracer regions connected respectively to the driving electrodes and the sensing electrodes, and shield layers disposed respectively on the tracer regions.