In-Cell Touch Screen Array Substrate Capacitance Control
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Solution Overview
Problem
Existing self capacitive touch screens experience adverse touch effects due to varying capacitances between touch electrodes and non-connection wires in their coverage regions, resulting from differences in overlapping areas and distances, which affect the accuracy and reliability of touch position detection.
Innovation Solution
The array substrate design ensures identical or approximately identical capacitances between touch electrodes and non-connection wires by adjusting the overlapping areas between them to be less than a predetermined threshold, achieved through specific arrangements of wires and resistive wires connected via via-holes, ensuring consistent capacitance across the touch screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wires are arranged to connect touch electrodes to touch detection circuit, then electrical connection is achieved, but varying overlapping areas cause capacitance differences that deteriorate touch detection accuracy
Solution Approach 1:
The patent applies local quality by making the wire structure asymmetric: one end of each wire has an extended segment that overlaps with the touch electrode coverage region, while the other end does not. This creates controlled, consistent overlapping areas at specific locations, ensuring uniform parasitic capacitance values across all touch electrodes while maintaining necessary electrical connections.
Solution Approach 2:
The patent changes the geometric parameters of the wire structure by introducing extended segments with specific lengths and positions. By controlling the overlapping area between wire extended segments and touch electrode coverage regions to be less than a predetermined threshold, the parasitic capacitance is standardized, thereby improving touch detection accuracy.
2Measurement precision
If wire overlapping areas with touch electrodes are reduced to minimize capacitance variation, then touch detection accuracy improves, but wire routing complexity increases
Solution Approach 1:
The patent segments each wire into distinct functional parts: a connection segment that connects to the touch electrode via via-hole, an extended segment that overlaps with the touch electrode coverage region, and a non-overlapping segment that connects to the touch detection circuit. This segmentation allows precise control of overlapping areas while simplifying the overall routing strategy.
Solution Approach 2:
The patent utilizes the vertical dimension by arranging wires and touch electrodes at different layers. The wires are positioned at a layer different from the touch electrodes, allowing three-dimensional routing that reduces planar complexity while maintaining controlled overlapping areas through vertical stacking.
3Manufacturing precision
If identical wire arrangements are used for all touch electrodes, then capacitance consistency improves, but adaptability to different touch electrode positions decreases
Solution Approach 1:
The patent creates a universal wire structure design that can be applied to all touch electrodes regardless of their positions. Each wire follows the same pattern with an extended segment, connection segment, and non-overlapping segment, making the design universally applicable across the entire touch screen while maintaining consistent capacitance characteristics.
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 touch effect of self capacitive touch screens by maintaining consistent capacitances between touch electrodes and non-connection wires, improving the accuracy and reliability of touch position detection.
Implementation Method 1
a layer of touch electrodes may be arranged in the touch screen, and a driving signal is applied to each touch electrode. When no touch has been made, a capacitance of the touch electrode is of a constant value a, and when the touch has been made by a finger, the resultant capacitance is a sum of a capacitance of the finger and the original capacitance a. By detecting a change in the capacitance of the touch electrode, it is able to determine a position where the touch is made.
Data Source
AI summary
The present disclosure provides an array substrate, an in-cell touch screen and a display device. The array substrate includes a plurality of touch electrodes arranged at an identical layer and separated from each other, and a plurality of wires arranged at a layer different from the touch electrodes and configured to connect the touch electrodes to a touch detection circuit. A difference in overlapping areas between each touch electrode and the wires corresponding to the other touch electrodes in a coverage region of the touch electrode is less than a predetermined threshold.