Touch-Fingerprint Sensor With Segmented Electrodes For Speed And Accuracy
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Solution Overview
Problem
Existing touch-fingerprint sensors face challenges in achieving optimal performance for both touch recognition and fingerprint authentication, with limitations in capacitance levels and recognition speed, which affect the overall user experience and accuracy.
Innovation Solution
A touch-fingerprint complex sensor design featuring distinct electrode configurations and layers, including non-overlapping touch and fingerprint electrodes, a fingerprint insulating layer, and a bonding layer, which allows for adjustable capacitance levels to enhance recognition speed and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate touch screen module and fingerprint recognition module are used, then functional completeness is achieved, but device complexity and space occupation increase
Solution Approach 1:
The patent combines the touch sensor and fingerprint sensor into a single integrated sensor structure. The touch electrodes and fingerprint electrodes are formed in the same substrate layer, sharing common components such as the lower electrode layer, insulating layers, and substrate. This merging eliminates the need for separate modules while maintaining both touch recognition and fingerprint authentication functions.
Solution Approach 2:
The integrated sensor structure serves multiple functions simultaneously. The same substrate and electrode layers are used for both touch sensing and fingerprint recognition operations. The sensor can detect both light touch events and fingerprint patterns using the shared electrode configuration, achieving multi-functionality without requiring separate dedicated modules.
2Measurement precision
If capacitance level is increased for better fingerprint recognition, then recognition accuracy improves, but touch recognition speed decreases
Solution Approach 1:
The patent implements different electrode configurations for different functional areas. The fingerprint electrodes are positioned closer to the common electrode to create higher capacitance for improved fingerprint recognition accuracy. Meanwhile, the touch electrodes are positioned to maintain lower capacitance values optimized for fast touch recognition. This local differentiation of electrode properties allows each function to operate at its optimal performance level.
Solution Approach 2:
The sensor system dynamically adjusts its operating parameters based on the detected input type. The control circuit can switch between fingerprint recognition mode and touch recognition mode, adjusting the readout timing and signal processing parameters accordingly. This dynamic operation allows the system to optimize performance for the current task, achieving high accuracy for fingerprints and high speed for touches.
3Reliability
If electrode overlap is increased to enhance capacitance, then sensing sensitivity improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent divides the electrode structure into distinct segments with clear spatial separation. The touch electrodes and fingerprint electrodes are positioned in different regions or at different depths, creating well-defined boundaries between functional zones. This segmentation simplifies the manufacturing process by reducing the need for precise overlapping alignment, as each electrode type has its designated position that can be formed using standard fabrication techniques.
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 design improves touch recognition speed and fingerprint recognition performance by maintaining low resistance in touch electrodes and high capacitance between common and fingerprint electrodes, resulting in enhanced user interaction and authentication accuracy.
Implementation Method 1
high capacitance between common and fingerprint electrodes
Implementation Method 2
maintaining low resistance in touch electrodes and high capacitance between common and fingerprint electrodes
Data Source
AI summary
A touch-fingerprint complex sensor includes a fingerprint substrate provided in a fingerprint area and a touch area, common electrodes provided above the fingerprint substrate in a direction that is normal to an upper surface of the fingerprint substrate, fingerprint electrodes provided between the fingerprint substrate and the common electrodes in the direction, and touch electrodes provided below the common electrodes and the fingerprint substrate in the direction, wherein a first subset of the common electrodes, and the fingerprint electrodes are provided in the fingerprint area, and a second subset of the common electrodes, and the touch electrodes are provided in the touch area.