Conductive Sheet Grid Structure for Precise Capacitive Touch Sensing
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Solution Overview
Problem
Conventional projected capacitive touch panels suffer from poor finger position detection accuracy, high production costs, and visibility issues due to electrode array configurations and material limitations, particularly when scaled for larger devices.
Innovation Solution
A conductive sheet with alternating rectangular wave-shaped lattices on opposing surfaces of a substrate, connected by medium lattices to form low-resistance conductive patterns, reducing electrical resistance and improving visibility by minimizing visible connections and thickness variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gaps are formed between first and second electrode arrays to prevent short circuit, then electrical insulation is improved, but finger position detection accuracy deteriorates
Solution Approach 1:
The patent transitions from a planar electrode arrangement to a three-dimensional stacked configuration. The first electrode array is positioned on the front surface while the second electrode array is positioned on the rear surface of the substrate, separated by the substrate thickness. This vertical separation in the third dimension eliminates the need for lateral gaps, allowing continuous electrode patterns that improve detection accuracy while maintaining electrical insulation through the substrate.
2Reliability
If insulation layers and electrode connections are formed at intersections of electrode arrays, then short circuit prevention is improved, but visibility deteriorates due to large thickness and black points
Solution Approach 1:
By positioning electrode arrays on opposite surfaces of the substrate, the patent eliminates the need for intersection connections within the same plane. The connections are made through the substrate thickness rather than at surface intersections, removing the cause of visible black points and thickness variations that degrade visibility.
Solution Approach 2:
The patent removes the problematic insulation layers and complex connection structures from the visible surface. Electrical connections are established through the substrate interior, extracting the connection function from the visible surface plane and eliminating the visual defects associated with surface-mounted connections.
3Quantity of substance
If ITO electrodes are used in large-sized touch panels, then material availability is improved, but response speed deteriorates due to high resistance and low current transfer rate
Solution Approach 1:
The patent employs a composite electrode structure combining ITO (indium tin oxide) with metal particles or other conductive materials. This composite approach maintains the ease of ITO fabrication while adding highly conductive metal components to reduce overall resistance, thereby improving current transfer rate and response speed in large-sized touch panels.
Solution Approach 2:
The patent modifies the electrical parameters of the electrode by changing its compositional structure. By incorporating metal particles or alternative conductive materials with lower resistivity into the ITO matrix, the overall electrical resistance is reduced, enabling faster response speeds while maintaining compatibility with existing ITO fabrication processes.
4Ease of manufacture
If conventional electrode array structures are used, then manufacturing process is simplified, but production cost increases due to mask patterns and insulation layers
Solution Approach 1:
The stacked configuration on opposite surfaces simplifies the manufacturing process by eliminating the need for complex multi-layer insulation patterns and intersection connections. The substrate itself serves as the insulation medium, reducing the number of fabrication steps and mask patterns required, thereby lowering production complexity and cost.
Data Source
AI summary
Disclosed are a conductive sheet, a usage method of the conductive sheet and a capacitive type touch panel. For a first conductive sheet, two or more conductive first large grids are formed atop a first transparent base, wherein each first large grid is constituted by combining two or more small grids, and the shapes of facing sides of each first large grid are formed to alternate. For example, rectangular waveshapes of a first side portion of the first large grid and of a fourth side portion facing the first side portion are made to alternate, and rectangular waveshapes of a second side portion of the first large grid and of a third side portion facing the second side portion are made to alternate.