Conductive Sheet Lattice Design for Capacitive Touch Panel Accuracy
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Solution Overview
Problem
Conventional projected capacitive touch panels suffer from low 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 design featuring conductive patterns with large lattices and medium lattices, arranged in specific configurations on both surfaces of a substrate, with optimized lattice sizes and connections to reduce electrical resistance and improve visibility, suitable for large-sized projected capacitive touch panels.
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 arranged on the front surface of the substrate while the second electrode array is arranged on the rear surface, utilizing the vertical dimension to separate electrodes that would otherwise require lateral spacing. This dimensional transition eliminates the need for gaps between electrode arrays while maintaining electrical insulation through the substrate thickness.
Solution Approach 2:
Instead of arranging both electrode arrays on the same surface with lateral separation, the patent inverts the conventional approach by placing one array on the front surface and the other on the rear surface of the substrate. This inverted spatial arrangement allows electrodes to be closely positioned without risk of short circuit, as the substrate itself provides the insulation barrier between the two surfaces.
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:
The patent eliminates the need for complex intersection handling by arranging electrode arrays in parallel on opposite surfaces rather than allowing them to cross. The first electrode array extends in a first direction on the front surface while the second electrode array extends in a second direction on the rear surface, with both arrays oriented to avoid intersections. This dimensional separation removes the requirement for thick insulation layers at crossing points, thereby maintaining visibility.
Solution Approach 2:
The patent extracts and eliminates the problematic intersection regions from the electrode array design. By configuring the arrays to run parallel to each other on opposite surfaces without crossing, the design removes the need for insulation layers and complex connection structures at intersections, thereby eliminating the source of visibility degradation.
3Reliability
If ITO electrodes are used in conventional projected capacitive touch panels, then conductivity is achieved, but resistance remains high at several tens of ohm/sq, resulting in low current transfer rate and slow response speed in large devices
Solution Approach 1:
The patent replaces the conventional single-material ITO electrode with a composite structure consisting of a transparent substrate and conductive patterns formed from low-resistance conductive material. The conductive patterns are designed with optimized geometry (line width, spacing, and arrangement) to achieve low electrical resistance while maintaining transparency. This composite approach combines the advantages of transparency from the substrate with the low resistance from the conductive material.
Solution Approach 2:
The patent changes the electrical parameters of the electrode system by using conductive materials with lower resistivity than ITO and optimizing the geometric parameters of the conductive patterns. By adjusting the line width, spacing, and arrangement of the conductive patterns, the patent achieves lower sheet resistance and improved current transfer rate, thereby increasing the response speed of the touch panel.
4Adaptability or versatility
If electrode arrays are arranged in matrix structure for multi-touch detection, then multi-touch capability is achieved, but production complexity and cost increase due to mask patterns and insulation layers
Solution Approach 1:
The patent simplifies the production process by utilizing the vertical dimension to separate the two electrode arrays on opposite surfaces of the substrate. This eliminates the need for complex multi-layer mask patterns and intermediate insulation structures required in conventional same-surface arrangements. The arrays can be formed using simpler single-sided patterning processes, reducing manufacturing complexity while maintaining multi-touch detection capability.
Solution Approach 2:
The patent extracts and removes the complex insulation layer structures and multi-step mask patterning processes from the manufacturing workflow. By designing the electrode arrays to be arranged on opposite surfaces in parallel without intersections, the patent eliminates the need for intermediate insulation layers and complex alignment processes, thereby simplifying the production process and reducing costs.
Data Source
AI summary
A conductive Sheet, a method for using conductive sheet, and a capacitive touch panel are provided. A first conductive sheet contains two or more conductive first large lattices and a first connection for electrically connecting the adjacent first large lattices on a first transparent substrate. The first large lattices each contain a combination of two or more small lattices, the first connection contains one or more medium lattices (a first medium lattice to a fourth medium lattice), and the pitch of the medium lattices is n times larger than that of the small lattices (in which n is a real number larger than 1).