Multi-Layer Touch Sensor Electrode Structure
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Solution Overview
Problem
Current touch sensors for display devices face challenges in achieving high optical, electrical, and mechanical properties, particularly in terms of transmittance, sensitivity, and resistance to deformation and corrosion, especially in flexible and thin-layered designs.
Innovation Solution
A touch sensor design featuring a multi-layered structure with a first transparent conductive oxide pattern, a metal pattern, and a second transparent conductive oxide pattern, along with a conductive capping pattern that covers the sensing electrodes, enhancing transmittance, reducing channel resistance, and improving flexibility and corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a simple single-layer conductive pattern is used, then the device structure is simple, but the transmittance and electrical properties are insufficient
Solution Approach 1:
The patent employs a multi-layer composite structure consisting of transparent conductive oxide patterns (such as ITO, IZO, AZO) stacked with metal patterns (such as Ag, Al, Mo). This composite structure achieves high transmittance in the visible spectrum while providing low electrical resistance through the metal layers, resolving the contradiction between optical performance and electrical properties without requiring excessive structural complexity
Solution Approach 2:
The patent transitions from a single-layer planar structure to a multi-layer stacked structure in the vertical dimension. By stacking transparent conductive oxide layers with metal layers alternately, the design achieves superior optical and electrical properties through dimensional expansion, allowing light transmission in the visible range while providing conductive pathways through the stacked layers
2Reliability
If metal patterns are used to improve electrical conductivity, then electrical resistance is reduced, but corrosion resistance to moisture and air deteriorates
Solution Approach 1:
The patent creates a protective composite structure where transparent conductive oxide layers (such as ITO, IZO, AZO) are stacked with metal layers. The transparent conductive oxide layers serve as barrier layers that protect the underlying metal patterns from corrosion by moisture and air, while still maintaining low electrical resistance through the metal layers and providing high transmittance in the visible spectrum
Solution Approach 2:
The transparent conductive oxide layers function as intermediary protective barriers between the metal patterns and the external environment (moisture and air). These intermediary layers prevent direct contact between the metal and corrosive elements, thereby protecting the electrical conductivity of the metal patterns while maintaining the overall electrical performance of the structure
3Reliability
If thick conductive layers are used to reduce resistance, then electrical conductivity improves, but flexibility and bending properties deteriorate
Solution Approach 1:
The patent employs a multi-layer composite structure with alternating transparent conductive oxide layers and thin metal layers. This composite design achieves low electrical resistance through the cumulative effect of multiple conductive layers while maintaining flexibility because each individual layer remains thin and the overall structure can bend without cracking
Solution Approach 2:
The patent divides the conductive structure into multiple segmented layers (transparent conductive oxide layers and metal layers stacked alternately) rather than using a single thick layer. This segmentation allows each layer to be thin and flexible while collectively providing the desired electrical conductivity, enabling the structure to maintain flexibility and bending properties
Data Source
AI summary
A touch sensor includes a base layer, a plurality of sensing electrodes and a conductive capping pattern covering each of the sensing electrodes. Each of the sensing electrodes includes a first transparent conductive oxide pattern, a metal pattern and a second transparent conductive oxide pattern which are sequentially stacked on the base layer.