Overlapping Fingerprint Sensor Units with Variable Density
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Solution Overview
Problem
The accuracy and sensitivity performance of fingerprint authentication in electronic devices need to be improved.
Innovation Solution
The electronic device includes a first unit with a high density of sub-units, a second unit with a lower density of sub-units overlapping with the first unit, and a third unit overlapping with both, where the second unit receives a first signal and the third unit receives a second signal. This configuration enhances fingerprint data reception by optimizing signal processing and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single unit with uniform sub-unit density is used for fingerprint sensing, then the device structure is simple, but the signal-to-noise ratio and authentication accuracy are insufficient
Solution Approach 1:
The sensor is divided into multiple units (first unit, second unit, third unit) with different sub-unit densities. Each unit segments the sensing area to perform different functions: high-density regions for detailed fingerprint pattern capture and low-density regions for broader signal reception, thereby improving overall measurement precision while managing complexity through functional segmentation
Solution Approach 2:
Different units are assigned different sub-unit densities tailored to their specific functional requirements. The first unit has high density for detailed ridge/valley detection, while the second and third units have lower densities optimized for their respective signal reception roles. This local optimization of quality parameters enhances fingerprint authentication accuracy without uniformly increasing complexity across the entire device
2Reliability
If multiple overlapping units with different signal reception functions are implemented, then the signal-to-noise ratio improves, but the device complexity increases
Solution Approach 1:
The first unit, second unit, and third unit are arranged in an overlapping nested configuration where units are disposed at different positions and orientations relative to each other. This nesting allows multiple signal reception functions to be integrated in a compact footprint, improving reliability through redundant and complementary signal paths while containing device complexity through space-efficient arrangement
Solution Approach 2:
Each unit serves multiple functions: the first unit not only receives fingerprint signals but also provides structural support; the second and third units with their different orientations receive signals from different angles, providing both signal diversity and structural stability. This multi-functionality improves reception reliability while minimizing the increase in device complexity
Data Source
AI summary
An electronic device includes a first unit, a second unit, and a third unit. The first unit includes a plurality of first sub-units. A second unit receives a first signal and includes a plurality of second sub-units, wherein the second unit is overlapped with the first unit. The third unit receives a second signal different from the first signal and includes a plurality of third sub-units, wherein the third unit is overlapped with the second unit and the first unit, and the first unit is disposed between the second unit and the third unit. A density of the plurality of the second sub-units is less than a density of the plurality of the first sub-units.