Semiconductor Fingerprint Sensor with 2D Differential Processing
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Solution Overview
Problem
Existing fingerprint sensing technologies face challenges in precise data extraction due to narrow signal detection ranges and issues like common mode signal removal and external noise, especially when using capacitive touch panels, leading to image distortion and reduced recognition accuracy.
Innovation Solution
A semiconductor device with a fingerprint sensor generating data in two perpendicular directions, utilizing a differential sensing circuit and processing circuit to perform differential operations and generate fingerprint data using 2D differential isotropic filters, which improves recognition precision and handles rotation by combining data from both directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fingerprint sensor is embedded in a capacitive touch panel to enable fingerprint recognition, then fingerprint sensing capability is added, but common mode signals and external noise are introduced that reduce recognition accuracy
Solution Approach 1:
The patent extracts and removes common mode signals from the sensed fingerprint data through differential operations. By comparing signals from adjacent sensing lines and subtracting common components, the system isolates the actual fingerprint ridge and valley information from noise and interference signals generated by the capacitive touch panel embedding.
2Measurement precision
If the detection range is narrowed to improve fingerprint sensing precision, then sensing precision is improved, but the ability to detect valid data is reduced
Solution Approach 1:
The patent transitions from one-dimensional signal detection to two-dimensional differential processing by performing differential operations in both horizontal and vertical directions. This multi-directional approach expands the detection capability while maintaining precision, allowing the system to capture valid fingerprint data through combined directional analysis rather than relying on a single narrow detection path.
3Measurement precision
If differential operations are performed in multiple directions to improve recognition precision, then recognition precision is improved, but processing complexity increases
Solution Approach 1:
The patent segments the fingerprint sensing process into distinct directional components, performing differential operations separately in horizontal and vertical directions. This segmentation allows the complex multi-directional processing to be broken down into manageable independent stages, reducing overall processing complexity while maintaining the precision benefits of multi-directional analysis.
Data Source
AI summary
A semiconductor device comprising a fingerprint sensor configured to generate first-direction sensing data and second-direction sensing data by sensing a fingerprint image in a first direction and a second direction, respectively, which is perpendicular to the first direction; a differential sensing circuit configured to generate first-direction first differential data and second-direction first differential data by performing a differential operation on the first-direction sensing data and the second-direction sensing data, respectively; and a fingerprint processing circuit configured to generate first-direction second differential data and second-direction second differential data by performing a differential operation on the first-direction first differential data and the second-direction first differential data, respectively, and generate fingerprint data by adding the first-direction second differential data and the second-direction second differential data.