Hollowed-Out Capacitive Touch Sensor for Higher Touch SNR
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Solution Overview
Problem
Existing capacitive touch sensors have a large initial capacitance and small capacitance change rate when touched, leading to low sensitivity and a poor signal-to-noise ratio, requiring complex software filtering to compensate.
Innovation Solution
A capacitive touch sensor design featuring a sensing electrode layer with hollowed-out patterns and suspended blocks, where the solid areas of the sensing electrodes fully overlap the driving electrodes, increasing the capacitance change rate and sensitivity by extending electric field lines beyond the overlapping area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large overlapping area is used between driving electrode and sensing electrode, then the initial capacitance is increased, but the capacitance change rate when touched is reduced
Solution Approach 1:
The sensing electrode layer is segmented into multiple sensing electrodes with hollowed-out patterns, creating distinct detection regions. This segmentation allows the electric field to be distributed more effectively, increasing the capacitance change rate when touched while maintaining adequate initial capacitance through the overall electrode arrangement.
Solution Approach 2:
The hollowed-out pattern creates local quality variations in the sensing electrode layer, with different regions having different capacitance characteristics. The hollowed areas allow electric field lines to extend beyond the overlapping region, enhancing the capacitance change rate in specific local regions while maintaining overall signal strength.
2Quantity of substance
If most electric field lines are confined between driving electrode and sensing electrode, then the initial capacitance is increased, but the sensitivity to touch is reduced
Solution Approach 1:
The hollowed-out pattern in the sensing electrode extracts or removes portions of the electrode material, allowing electric field lines to extend beyond the immediate overlapping region between driving and sensing electrodes. This extraction enables more field lines to interact with the touch surface, improving sensitivity while maintaining adequate initial capacitance.
Solution Approach 2:
The hollowed-out pattern introduces a dimensional variation in the electrode structure, creating three-dimensional field distribution rather than confined two-dimensional overlap. This dimensional change allows electric field lines to extend in additional spatial directions, increasing touch sensitivity without sacrificing initial capacitance.
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 design enhances the sensitivity and signal-to-noise ratio of touch detection, allowing for more accurate data acquisition and improved touch detection performance in touch terminals.
Implementation Method 1
the initial capacitance between the driving electrode and the sensing electrode is thus relatively large... only a small change in capacitance can be generated between the driving electrode 14 and the sensing electrode 12
Implementation Method 2
most of the electric field lines EL are between the driving electrode 14 and the sensing electrode 12
Data Source
AI summary
The present invention relates to touch detection technology and provides a capacitive touch sensor which comprises a driving electrode layer and a sensing electrode layer. An insulating isolation layer is disposed between the sensing electrode layer and the driving electrode layer. A touch panel is disposed over the sensing electrode layer, and the sensing electrode layer has hollowed-out sensing electrodes. The present invention provides a new sensor structure in which the sensing electrode layer (such diamond, rectangular, round etc.) is hollowed-out to improve sensitivity of touch detection and the signal to noise ratio (SNR).