Touch Sensor Dual-Layer Electrode Structure for Resistance and Aperture Ratio
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Solution Overview
Problem
Existing touch sensors face challenges in simultaneously reducing resistance while maintaining or improving aperture ratio and transmittance, and in minimizing pattern visibility, particularly due to the visual recognition of bridges in metal mesh electrode layers.
Innovation Solution
A touch sensor design featuring a dual-layer electrode structure with main and auxiliary electrode cells arranged in a mesh pattern, separated by insulation pads in an island shape, which eliminates the need for bridges and optimizes resistance and transmittance by stacking and connecting the layers vertically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode area is increased to lower resistance, then resistance decreases, but aperture ratio and transmittance decrease
Solution Approach 1:
The patent transitions from a single-plane electrode layout to a multi-layer stacked electrode structure. By arranging electrode cells across multiple layers and connecting them vertically, the conductive path is extended in the vertical dimension while maintaining a compact horizontal footprint. This allows achieving lower resistance without increasing the horizontal electrode area that would block light, thus preserving aperture ratio and transmittance.
Solution Approach 2:
The patent implements a nested arrangement where electrode cells in different layers are stacked vertically, with upper-layer electrodes positioned within the vertical projection of lower-layer electrodes. This nesting allows multiple electrode cells to occupy the same horizontal space at different heights, effectively increasing the total conductive area and reducing resistance without increasing the horizontal aperture blockage.
2Reliability
If bridges are used to connect electrode cells, then connectivity is achieved, but bridges are visually recognized and reduce visibility
Solution Approach 1:
Instead of using horizontal bridges on the same plane to connect electrode cells, the patent utilizes vertical connections through multiple layers. The inter-layer connections are made through the insulation layer in the vertical dimension, making the connection paths invisible from the front view, thus eliminating visual recognition while maintaining connectivity.
Solution Approach 2:
The patent extracts the connection function from the visible plane by moving connections to the vertical inter-layer space. The bridges that would normally be visible on the electrode plane are replaced by vertical inter-layer connections that are hidden from the user's view, separating the connectivity function from the visible surface.
3Illumination intensity
If a metal mesh electrode layer is used, then transmittance is improved, but pattern visibility increases due to the mesh structure
Solution Approach 1:
The patent employs nested mesh patterns across multiple layers, where the mesh structures of different layers are offset and stacked. This nesting creates a more uniform light transmission profile by distributing the mesh patterns in the vertical dimension, reducing the visibility of individual mesh patterns while maintaining high overall transmittance.
Data Source
AI summary
A touch sensor comprises a first electrode layer, a second electrode layer, and an insulation layer. The first electrode layer includes first main electrode cells connected and arranged in a first direction and second auxiliary electrode cells separated from the first main electrode cells and arranged separately in a second direction on the same lower plane. The second electrode layer includes first auxiliary electrode cells arranged separately in the first direction and stacked and connected to the first main electrode cells while having the same pattern as the first main electrode cells and second main electrode cells separated from the first auxiliary electrode cells, connected and arranged in a second direction, and stacked and connected to the second auxiliary electrode cells while having the same pattern as the second auxiliary electrode cells, on the same upper plane. The insulation layer is formed between the first electrode layer and the second electrode layer.