Anisotropic Micro-Wire Electrodes for Touch Screens
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Solution Overview
Problem
Current transparent conductive electrodes in touch screens face limitations in achieving high conductivity and transparency, often compromising on one attribute to maintain the other, and are prone to mechanical stress, which affects their performance in capacitive touch-screen devices.
Innovation Solution
The development of anisotropically conductive electrodes with micro-wire patterns that include straight and angled micro-wires, forming a micro-pattern that enhances conductivity in specific directions while maintaining transparency, by using a substrate with micro-wires that are either directly on or under the transparent substrate, allowing for improved electrical conductivity and reduced resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional transparent conductive electrodes are used, then transparency is maintained, but electrical conductivity is insufficient
Solution Approach 1:
The electrode is segmented into multiple thin metal wire layers (first metal wire layer and second metal wire layer) with different orientations. Each layer contains multiple wires spaced apart, creating a mesh-like structure that provides both transparency and enhanced conductivity through the cumulative effect of multiple conductive paths.
Solution Approach 2:
The invention uses a composite structure combining multiple metal wire layers with different orientations (first layer with wires in first direction, second layer with wires in second direction). This composite arrangement achieves superior electrical conductivity while maintaining transparency, as the multi-layered wire structure provides more conductive pathways without requiring excessive wire density in any single layer.
2Illumination intensity
If transparent conductive materials are made thinner to improve transparency, then transparency increases, but electrical conductivity decreases
Solution Approach 1:
Instead of using a single thin layer, the conductive structure is segmented into multiple thin wire layers. Each layer contains multiple individual wires that are thin enough to maintain transparency, but the collective arrangement of multiple layers provides sufficient total conductivity through increased conductive pathways.
Solution Approach 2:
The invention transitions from a single-plane conductive structure to a multi-layered three-dimensional arrangement. By stacking multiple wire layers at different orientations, the structure achieves enhanced conductivity in multiple directions without increasing the wire density in any single plane, thus maintaining transparency.
3Reliability
If micro-wire density is increased to improve conductivity, then electrical conductivity improves, but transparency decreases
Solution Approach 1:
The invention employs a composite wire structure where multiple thin wire layers with different orientations are combined. This arrangement achieves high effective conductivity through the synergistic effect of multiple conductive paths without requiring high wire density in any single layer, thus maintaining transparency.
Solution Approach 2:
By adding the vertical dimension with multiple stacked wire layers, the structure achieves enhanced conductivity without increasing the horizontal wire density. The multi-layered configuration provides more conductive pathways through space rather than through increased material density, preserving transparency.
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 solution provides a 50% improvement in conductivity and a 17% reduction in transparency, enabling better electrical field uniformity and increased capacitance, thus enhancing the performance of capacitive touch-screen devices while maintaining user visibility.
Implementation Method 1
The touch screen includes a first transparent substrate with first transparent electrodes formed in the x dimension and a second transparent substrate with second transparent electrodes formed in the y dimension... When a voltage is applied across the first and second transparent electrodes, electric fields are formed between the first pad areas and the second pad areas
Implementation Method 2
Capacitive touch-screens are of at least two different types: self-capacitive and mutual-capacitive. Self-capacitive touch-screens employ an array of transparent electrodes, each of which in combination with a touching device forms a temporary capacitor whose capacitance is detected
Data Source
AI summary
A method of making a touch-responsive capacitive device includes providing a transparent substrate and forming anisotropically conductive first and second electrodes extending in corresponding first and second orthogonal length directions over the substrate. Anisotropically conductive first and second electrodes each with electrically connected micro-wires are formed on opposing sides of the transparent substrate. The anisotropically conductive first and second electrodes extend in corresponding first and second length directions. The first and second micro-wires are formed with substantially parallel straight micro-wires extending substantially in the corresponding first and second length directions and a plurality of angled micro-wires are formed at a non-orthogonal angle to the straight micro-wires and electrically connect the straight micro-wires so that the anisotropically conductive first and second electrodes have a greater electrical conductivity in the corresponding first and second length directions than in another anisotropically conductive electrode direction.