Touch Module Dual Grid Dummy Electrodes Impedance
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Solution Overview
Problem
Large metal grid touch screens face issues with reduced touch sensitivity and performance due to increased circuit impedance and parasitic capacitances, affecting the uniformity of touch data and sensitivity as screen size increases.
Innovation Solution
The touch module incorporates a dual metal grid layer structure with dummy electrodes arranged in parallel to reduce resistance and parasitic capacitances, ensuring equal impedance and signal attenuation across the touch electrodes, thereby improving touch sensitivity and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the screen size is increased, then the coverage area is improved, but the touch sensitivity and touch performance deteriorate due to increased circuit impedance and parasitic capacitances
Solution Approach 1:
The touch screen is divided into two separate metal grid layers, each functioning as an independent touch sensing layer. This segmentation allows each layer to have optimized electrode distributions that reduce parasitic capacitances and circuit impedance, thereby maintaining touch sensitivity across larger screen areas
Solution Approach 2:
The patent transitions from a single-layer touch screen to a dual-layer structure, adding a vertical dimension to the electrode arrangement. The first and second metal grid layers are positioned at different heights, creating three-dimensional electrode intersections that reduce parasitic capacitance while maintaining large area coverage
2Area of stationary object
If the screen size is increased, then the coverage area is improved, but the uniformity of touch data deteriorates due to increased parasitic capacitances
Solution Approach 1:
Each metal grid layer is designed with locally optimized electrode patterns and distributions tailored to compensate for position-dependent variations in parasitic capacitance. The electrode arrangements are customized for different regions of the screen to ensure uniform touch data collection across the entire large area
Solution Approach 2:
The dual-layer structure with orthogonal electrode arrangements creates more uniform potential distribution across the screen surface. The intersecting grid patterns from two layers help equalize the electrical characteristics at different positions, reducing variations in touch data uniformity
3Area of stationary object
If the screen size is increased, then the coverage area is improved, but the impedance of touch electrodes increases
Solution Approach 1:
The touch electrode function is segmented across two separate metal grid layers, with each layer contributing partially to the overall touch sensing. This distribution of the electrode function reduces the impedance burden on individual electrodes while maintaining large screen coverage
Solution Approach 2:
By stacking two metal grid layers vertically with orthogonal electrode orientations, the patent creates three-dimensional touch detection paths. This dimensional change provides multiple parallel current paths, effectively reducing the overall impedance of the touch electrode system across large screen areas
Data Source
AI summary
The present application provides a touch module and a touch screen. The touch module includes a first metal grid layer and a second metal grid layer. First touch electrodes are disposed in the first metal grid layer and arranged along a first direction, and each of the first touch electrodes extends along a second direction which intersects the first direction. Second touch electrodes are disposed in the second metal grid layer and arranged along the second direction, and each of the second touch electrodes extends along the first direction. The touch module further includes a first dummy electrode and a second dummy electrode, where the first dummy electrode is coupled to a part of the second touch electrode in parallel and the second dummy electrode is coupled to a part of the first touch electrode in parallel.