Narrow Bezel Touch Sensor via Nanowire-Silver Edge Control
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Solution Overview
Problem
Current touch sensors with silver paste peripheral circuits face challenges in achieving flexibility and narrow bezel designs due to the limitations of silver paste in forming patterns that meet both flexibility and aesthetic requirements.
Innovation Solution
A touch sensor design featuring a metal nanowire layer and a silver layer with specific edge roughness characteristics, where the silver layer is stacked on the nanowire wiring, allowing for a smoother edge and eliminating the need for additional overlapping structures, thereby enabling a narrower bezel and reduced manufacturing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If silver paste is used as material for peripheral circuits with screen-printing process, then the peripheral circuits can be formed in the peripheral area, but the edge roughness is large and the bezel width cannot be reduced
Solution Approach 1:
The patent changes the material parameter from traditional silver paste to metal nanowire network layer, which fundamentally alters the edge roughness characteristic. The nanowire network enables formation of peripheral circuits with significantly reduced edge roughness, allowing the outermost peripheral trace edge roughness to be controlled within 1-10 μm, thus enabling narrow bezel design
Solution Approach 2:
The patent employs a composite structure combining metal nanowire network layer and silver layer. The metal nanowire network layer serves as the base pattern layer providing low edge roughness, while the silver layer is selectively formed on specific regions. This composite material approach leverages the advantages of both materials to achieve both low edge roughness and good electrical conductivity
2Reliability
If additional overlapping structures are added to ensure electrical connection, then the electrical connection reliability is improved, but the manufacturing complexity and area increase
Solution Approach 1:
The patent merges the pattern layer and electrode layer into a single metal nanowire network layer. The peripheral circuits and touch electrodes are both formed from the same nanowire network material, eliminating the need for separate overlapping structures to ensure electrical connection. This integration maintains electrical reliability while significantly reducing manufacturing complexity
Solution Approach 2:
The metal nanowire network layer serves multiple functions simultaneously: it acts as both the peripheral circuit pattern layer and the touch electrode layer. This multi-functional design eliminates the need for additional overlapping structures that would otherwise be required to ensure electrical connection between separate layers
Data Source
AI summary
A touch sensor having a visible area and a peripheral area includes a substrate, a metal nanowire layer, and a silver layer. The metal nanowire layer is disposed on a main surface of the substrate and defines an electrode portion and first and second wirings, in which the first wiring includes a lead-out portion connected to the electrode portion and a lead portion connected to the lead-out portion, and the second wiring is disposed on a side of the first wiring relatively away from the visible area and adjacent to an edge of the main surface. The silver layer is stacked on the first and second wirings and has a first side facing toward the visible area and a second side facing away from the visible area, and an edge roughness on the first side is greater than an edge roughness on the second side.