Touch Driving Electrode Inner Contour Parasitic Capacitance
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Solution Overview
Problem
Conventional touch display substrates have touch driving electrodes with greater width, resulting in higher parasitic capacitance and reduced touch sensitivity due to longer signal delays during the touch driving phase.
Innovation Solution
The touch display substrate features touch driving electrodes with an inner contour that reduces their area, allowing a common electrode to be disposed within, and an increased number of edges to enhance fringe field capacitance between the touch driving and sensing electrodes, improving touch sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the touch driving electrode width is increased to improve signal strength, then the signal intensity is improved, but the parasitic capacitance increases causing longer delay and reduced touch sensitivity
Solution Approach 1:
The touch driving electrode is segmented into a frame-shaped structure with an inner contour that defines a hollow area. This segmentation reduces the total area of the electrode while maintaining its outer dimensions, thereby reducing parasitic capacitance and signal delay while preserving signal intensity through the distributed edge structure.
2Loss of time
If the touch driving electrode area is reduced to decrease parasitic capacitance, then signal delay is reduced and touch sensitivity is improved, but the fringe field capacitance may be insufficient
Solution Approach 1:
The touch driving electrode employs a frame-shaped structure with curved edges at its four corners. These curved edges increase the effective perimeter length compared to a straight-edged rectangle of the same area, thereby enhancing fringe field capacitance while maintaining reduced parasitic capacitance through the hollow center design.
3Object-generated harmful factors
If the touch driving electrode is made into a frame shape with inner contour, then the electrode area is reduced decreasing parasitic capacitance, but the manufacturing complexity increases
Solution Approach 1:
The frame-shaped touch driving electrode is formed as an integrated structure in the same manufacturing process as the common electrode lines, merging two functional elements into a single fabrication step. This approach reduces manufacturing complexity despite the increased geometric complexity of the electrode pattern.
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 configuration reduces parasitic capacitance, shortens signal delays, and increases touch sensitivity by increasing the total fringe field capacitance, while maintaining the same signal intensity, thereby enhancing the overall performance of the touch display substrate.
Implementation Method 1
the touch driving electrodes have relatively greater width and hence relatively greater parasitic capacitance
Implementation Method 2
increasing the total number of edges of the individual touch driving electrode contributing to fringe field capacitance between the touch driving electrode and a corresponding touch sensing electrode
Data Source
AI summary
A touch display panel is provided. The touch display panel includes a plurality of touch driving electrodes and a plurality of touch sensing electrodes intersecting with and electrically insulated from the plurality of the touch driving electrodes. An individual touch driving electrode of the plurality of touch driving electrodes has an outer contour and an inner contour, the inner contour at least partially defining an area allowing a common electrode to be disposed therein, and an area of the individual touch driving electrode is substantially less than that defined by the outer contour.