Touch Sensor Mesh Patterns to Reduce Moiré Interference
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Solution Overview
Problem
Existing touch sensors with identical mesh patterns for transmission and reception electrodes suffer from moiré interference, affecting visibility and touch accuracy, and varying pitch settings exacerbate these issues.
Innovation Solution
The touch sensor employs first and second electrodes with distinct mesh patterns, where the first mesh pattern consists of diamond-shaped cells with an acute angle ranging from 50° to 65°, and the second mesh pattern consists of square-shaped cells, with a specific angle alignment between the diagonal lines of these cells, to reduce moiré and maintain touch accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the pitch of the thin wires is reduced to make the wires less visible, then the wire visibility is improved, but the number of intersections increases which increases the capacitance and impairs the touch accuracy
Solution Approach 1:
The patent applies asymmetry by using different mesh patterns for the transmission electrode and reception electrode. Specifically, one electrode uses a square mesh pattern while the other uses a triangular mesh pattern. This asymmetric design prevents the formation of regular interference patterns (moiré) that would occur with identical mesh patterns, while allowing the pitch to be optimized for both visibility and touch accuracy without the harmful effect of moiré interference
2Measurement precision
If the pitch of the thin wires is increased to reduce the number of intersections and capacitance, then the touch accuracy is improved, but the wires become more visible and degrade the appearance
Solution Approach 1:
By using asymmetric mesh patterns (square for one electrode, triangular for the other), the patent allows the pitch to be increased for better touch accuracy without creating regular moiré patterns that would make the wires more visible. The irregular interference pattern from asymmetric meshes is less noticeable to the human eye
3Ease of manufacture
If the transmission electrode and reception electrode have the same mesh pattern, then the manufacturing is simplified, but moiré occurs which impairs the visibility
Solution Approach 1:
The patent uses different mesh patterns for the transmission and reception electrodes to eliminate moiré and improve visibility. While this increases manufacturing complexity compared to using identical patterns, the patent mitigates this by using relatively simple geometric patterns (square and triangular meshes) that can be manufactured using standard techniques
Solution Approach 2:
The patent applies different mesh patterns at different locations (transmission electrode vs. reception electrode) to achieve the desired effect. Each electrode maintains a consistent pattern, but the two electrodes have different patterns, combining local consistency with global differentiation
Data Source
AI summary
A first mesh pattern (13) of a touch sensor (1) includes first cells (15) in a diamond shape with an acute angle (A1). A second mesh pattern (16) of the touch sensor (1) includes second cells (18) in a square shape. The acute angle (A1) ranges from 50° to 65°. One of second thin wires (17) of each second cell (18) and the longer diagonal line 15a of associated one of the first cells (15) form an angle A2 ranging from 15° to 75° in a plan view.