Touch Panel Asymmetric Overlap Reduces Coupled Capacitance
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Solution Overview
Problem
Dual ITO touch panels face limitations in accuracy and sensitivity due to coupled capacitance in the overlapping areas of their conductive wires, necessitating an enhancement in sensitivity.
Innovation Solution
The implementation of a touch panel design featuring mesh (palisade) conductive wires, where the first and second transparent conductive wires intersect in overlapping areas with projection centroids not aligned, reducing the overlapping area ratio and thereby minimizing coupled capacitance, and incorporating sub-wires and hollow areas to optimize capacitance distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional dual ITO conductive wires with aligned overlapping areas are used, then the manufacturing process is simple, but the touch panel accuracy and sensitivity are limited due to high coupled capacitance
Solution Approach 1:
The patent applies asymmetry by intentionally misaligning the projection centroids of overlapping areas between first and second conductive wires. Instead of symmetric alignment that maximizes overlap, the design creates asymmetric overlapping patterns where centroids are deliberately offset, reducing coupled capacitance and improving touch sensitivity while maintaining manufacturing feasibility
Solution Approach 2:
The conductive wires are segmented into multiple sub-wires (first sub-conductive wires and second sub-conductive wires) that intersect to form multiple discrete overlapping areas. This segmentation allows the overall overlapping pattern to be controlled and optimized, reducing total coupled capacitance while maintaining electrical connectivity and signal integrity
2Reliability
If the overlapping area ratio between conductive wires is increased to improve signal strength, then the signal strength improves, but the coupled capacitance increases reducing sensitivity
Solution Approach 1:
The patent applies local quality by creating non-uniform overlapping patterns where different regions have different overlapping characteristics. The hollow areas and varied centroid positions create zones with different capacitance values, optimizing the balance between signal strength in high-overlap regions and sensitivity in low-overlap regions
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 increases the accuracy and sensitivity of the touch panel by reducing the overlap capacitance and maintaining impedance stability even with breaking points, enhancing user input detection precision.
Implementation Method 1
a first transparent conductive wire and a second transparent conductive wire... the first transparent conductive wire includes a first conductive portion and a second conductive portion
Implementation Method 2
the accuracy and sensitivity of the dual ITO touch panel is limited by the coupled capacitance of the overlapping part of the two conductive wires
Data Source
AI summary
A touch panel includes a first transparent conductive wire and a second transparent conductive wire. The first transparent conductive wire is of a first conductive layer and the second transparent conductive wire is of a second conductive layer. The first transparent conductive wire includes a first conductive portion parallel to a first axis and a second conductive portion parallel to a second axis, wherein the first transparent conductive portion and the second transparent conductive portion commonly have a first overlapping area. The second transparent conductive wire includes a third conductive portion parallel to the first axis and a fourth conductive portion parallel to the second axis, wherein the third transparent conductive portion and the fourth transparent conductive portion commonly have a second overlapping area. The projection centroid of the first overlapping area is not in the same position as the projection centroid of the second overlapping area.