Touch Sensor Mesh Line Spacing for Moiré Reduction
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Solution Overview
Problem
Current touch sensors face challenges in optimizing line spacing in mesh designs for effective touch detection and minimizing optical interference, such as moiré patterns, which affect the accuracy and user experience of touch-sensitive displays.
Innovation Solution
The implementation of a mesh design with conductive lines oriented at specific angles and spacings, such as angles 54 and 56, which are calculated based on the pixel pitch, to create a mesh pattern that minimizes optical interference and enhances touch sensitivity while maintaining display clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conductive lines are placed closer together to improve touch detection sensitivity, then touch detection accuracy is improved, but optical interference such as moiré patterns increases
Solution Approach 1:
The patent changes the angular orientation parameter of conductive lines relative to pixel rows and columns. By setting specific angles (e.g., 45 degrees or other optimized values), the mesh pattern creates a beating pattern that reduces moiré effects while maintaining adequate line density for touch detection. This parameter optimization allows closer line spacing without proportionally increasing optical interference.
Solution Approach 2:
The patent employs asymmetric angular orientations for conductive lines relative to the pixel grid. Instead of aligning lines with pixel rows or columns (symmetric alignment), the lines are oriented at specific asymmetric angles that disrupt the regular interference patterns causing moiré effects, while still providing sufficient spatial sampling for accurate touch detection.
2Object-affected harmful factors
If conductive lines are spaced further apart to reduce moiré patterns, then optical interference is reduced, but touch detection sensitivity decreases
Solution Approach 1:
The patent optimizes the angular parameter of conductive lines to achieve a balance where lines can be spaced further apart without losing touch detection sensitivity. The specific angular orientation creates an effective sampling pattern that maintains detection accuracy while reducing the visual impact of the mesh pattern on the display.
Solution Approach 2:
The patent introduces angular orientation as an additional design dimension beyond simple line spacing. By utilizing the angular dimension, the system can achieve equivalent or superior touch detection performance with larger physical spacing between lines, thereby reducing moiré patterns without sacrificing sensitivity.
3Ease of operation
If mesh pattern line spacing is optimized for touch detection, then touch sensitivity is enhanced, but display clarity is compromised
Solution Approach 1:
The patent changes the angular parameter of the mesh pattern to reduce its visual prominence. By orienting conductive lines at specific angles relative to the pixel grid, the pattern creates a beating effect that distributes visual intensity more evenly, reducing localized dark lines and improving overall display clarity while preserving touch sensitivity.
Solution Approach 2:
The patent converts the potentially harmful moiré interference pattern into a beneficial beating pattern through careful angular selection. The interference between the mesh pattern and pixel grid creates a distributed pattern that reduces the visibility of individual conductive lines, thereby improving display clarity while the underlying mesh structure maintains touch detection sensitivity.
Data Source
AI summary
An apparatus includes a touch sensor that includes a mesh of multiple first and second lines of conductive material extending across a display, where the display includes multiple pixels. The first lines are substantially parallel to each other, and the second lines are substantially parallel to each other. Each of the pixels has a first pixel pitch (PPx) along a first axis and a second pixel pitch (PPy) along a second axis that is perpendicular to the first axis. The first pixel pitch is equal to a distance between corresponding features of two adjacent pixels along the first axis, and the second pixel pitch is equal to a distance between corresponding features of two adjacent pixels along the second axis. The first and second lines extend across the display at first and second angles, respectively, relative to the first axis.