Touch-Fingerprint Sensor Electrode Spacing Optimization
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Solution Overview
Problem
Current touch-fingerprint sensors face challenges in enlarging size, increasing driving speed, and enhancing fingerprint recognition depth due to limitations in electrode design, which affect visibility and Moiré formation, and result in restricted capacitance values that hinder efficient touch and fingerprint detection.
Innovation Solution
The implementation of a touch-fingerprint complex sensor with a step adjusting layer that varies the cross-sectional distance and height differences between electrodes in touch and fingerprint recognizing regions, adjusting mutual capacitance to optimize sensing performance and visibility, allowing for larger sizes and higher recognition depths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the electrode design uses uniform cross-sectional distance and height difference across the touch pad, then the manufacturing process is simple, but the sensing performance and visibility characteristics are degraded
Solution Approach 1:
The patent applies local quality by varying the cross-sectional distance and height difference between first and second electrodes in different regions of the touch pad. Specifically, the touch region has different electrode spacing characteristics compared to the fingerprint recognition region, allowing each region to be optimized for its specific sensing requirements while using the same basic electrode structure type.
2Area of stationary object
If the touch pad size is enlarged, then the touch area increases, but the driving speed decreases and Moiré formation increases
Solution Approach 1:
The patent changes physical parameters of the electrode structure, specifically the cross-sectional distance and height difference between electrodes, to optimize performance. By adjusting these parameters in different regions, the patent achieves improved driving speed and reduced Moiré effects while maintaining large touch pad area.
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
This approach enables enlarged touch pads with increased driving speed and improved fingerprint recognition depth, reducing Moiré formation and enhancing sensing characteristics by selectively controlling capacitance values between electrodes.
Implementation Method 1
A mutual capacitance at the intersections of the plurality of first electrodes and the plurality of second electrodes in the touch region excluding the fingerprint recognizing region may be less than a mutual capacitance at the intersections of the plurality of first electrodes and the plurality of second electrodes in the fingerprint recognizing region
Data Source
AI summary
A touch-fingerprint complex sensor is provided for detecting a touch and a fingerprint of a user, using a touch pad including a touch region and a fingerprint recognizing region. The touch-fingerprint complex sensor includes a plurality of first electrodes disposed on a substrate, and arranged in parallel in a first direction, a plurality of second electrodes disposed on the substrate, and arranged in parallel in a second direction crossing the first direction, and an insulating layer disposed between the plurality of first electrodes and the plurality of second electrodes. A cross-sectional distance between the plurality of first electrodes and the plurality of second electrodes at intersections of the plurality of first electrodes and the plurality of second electrodes in the touch region excluding the fingerprint recognizing region is greater than that at intersections of the plurality of first electrodes and the plurality of second electrodes in the fingerprint recognizing region.