Asymmetric Touch Panel Electrode Design for Moire Prevention
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Solution Overview
Problem
Current touch panels using metal thin wires face challenges in manufacturing due to the need for precise positioning and shape accuracy, leading to issues like spreading and interference fringes, especially in high-resolution displays, which increases costs and reduces yield.
Innovation Solution
A touch panel design where first and second electrodes are laid such that second-direction cross bands correspond to first-direction gaps and first-direction cross bands correspond to second-direction gaps, allowing for larger tolerance in alignment and shape variations, preventing spreading and interference fringes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If metal thin wires are used to form electrode arrays in a projected capacitive type touch panel, then responsiveness is improved, but manufacturing precision requirements increase and cost increases
Solution Approach 1:
The patent applies asymmetry by designing the first and second electrode arrays with different patterns. Specifically, the first electrode array has conducting wires arranged in a first pattern while the second electrode array has conducting wires arranged in a second pattern that is asymmetric relative to the first. This asymmetric design ensures that even when layers are stacked, the conducting wires do not align to form continuous lines, thereby preventing moire patterns while maintaining manufacturing feasibility with metal thin wires
Solution Approach 2:
The patent segments the electrode arrays into two separate layers with different conducting wire patterns. Instead of using a single symmetric pattern that would require high precision alignment, the conducting wires are divided into two sets (first and second electrode arrays) with different arrangements. This segmentation allows each layer to be manufactured independently with relaxed tolerance, reducing the need for high-precision positioning while maintaining overall system performance
2Illumination intensity
If metal thin wires are used to form electrode arrays, then visual quality degrades due to spreading and interference fringes, but manufacturing complexity increases
Solution Approach 1:
The asymmetric arrangement of conducting wires in the first and second electrode arrays prevents moire patterns and interference fringes from forming. By ensuring that the conducting wires in one layer do not align with those in the other layer through asymmetric patterning, the visual quality is maintained without requiring complex manufacturing processes to achieve precise alignment
Solution Approach 2:
Instead of trying to achieve perfect alignment to prevent moire patterns (which would increase manufacturing complexity), the patent inverts the approach by deliberately designing misalignment through asymmetric patterns. This inversion transforms the problem from one requiring high-precision alignment to one where controlled asymmetry is the solution, thereby reducing manufacturing complexity while maintaining visual quality
3Manufacturing precision
If high precision is required for forming patterns and laying patterns on each other, then yield reduces and cost increases
Solution Approach 1:
The asymmetric design of the electrode arrays eliminates the need for high-precision alignment during manufacturing. Since the conducting wires in the first and second electrode arrays are arranged in different patterns, slight misalignments during the stacking process do not result in visible moire patterns or functional issues. This asymmetry provides built-in tolerance that significantly reduces manufacturing precision requirements and improves production yield
Solution Approach 2:
The patent incorporates design features that beforehand cushion against potential alignment errors. By designing the electrode arrays with asymmetric patterns and appropriate spacing, the structure is pre-configured to tolerate certain degrees of misalignment without compromising performance or visual quality. This beforehand cushioning approach prevents yield loss that would otherwise occur due to manufacturing variations
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enables the manufacture of touch panels with improved accuracy and reduced costs, supporting large-screen or high-definition displays with enhanced sensitivity and visual quality.
Implementation Method 1
the change of electrostatic capacitance between the first electrode arrays and the second electrode arrays caused by capacitance coupling at the time of touch is detected as a change of voltage
Implementation Method 2
the change of electrostatic capacitance between the first electrode arrays and the second electrode arrays caused by capacitance coupling at the time of touch
Data Source
AI summary
A touch panel includes: a first electrode in which second-direction parallel bands having a plurality of conducting wires disposed to extend in parallel with one another and along a second direction intersecting with a first direction are formed repeatedly in the first direction with interposition of first-direction gaps in the first direction, and first-direction cross bands having conducting wires disposed to extend in the first direction and intersect with the second-direction parallel bands are formed repeatedly in the second direction; and a second electrode in which first-direction parallel bands are formed as defined herein, and second-direction cross bands are formed as defined herein, and the first electrode and the second electrode are laid on each other so that the second-direction cross bands correspond to positions of the first-direction gaps and the first-direction cross bands correspond to positions of the second-direction gaps.