Randomized Mesh Vertices for Touch Sensor Moiré Reduction

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Solution Overview

Problem

Capacitive touch sensors face challenges in minimizing moiré-pattern effects, which lead to brightness variations and optical interference when overlaid on display screens, affecting the optical performance and user experience.

Innovation Solution

A touch sensor design featuring a conductive mesh pattern with randomized vertices and angles, optimized to reduce the visibility of moiré patterns by distributing seed locations and vertices randomly within defined annuli, thereby minimizing repeating patterns and frequencies that cause optical interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a regular mesh pattern is used in the touch sensor, then the manufacturing and design are simplified, but moiré-pattern effects and optical interference occur

Engineering Contradiction:

Improvemesh design simplicityVSAvoidmoiré-pattern effects

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent applies asymmetry by randomizing the positions of mesh vertices and varying the angles between adjacent mesh lines, creating an irregular pattern that breaks the periodicity causing moiré effects while maintaining manufacturing feasibility through algorithmic generation

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent changes the geometric parameters of the mesh pattern by distributing vertices randomly within annular regions and varying line angles, transforming the regular pattern into an irregular one that eliminates optical interference while preserving the conductive function

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If the mesh line density is increased to improve touch sensitivity, then the touch detection capability is enhanced, but optical interference and moiré patterns become more visible

Engineering Contradiction:

Improvetouch detection sensitivityVSAvoidoptical interference

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

By introducing asymmetry through random vertex distribution and variable line angles, the patent allows for higher line density without creating the periodic patterns that cause moiré effects, thus improving touch sensitivity while maintaining optical quality

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent implements local quality variations by distributing mesh lines with different densities and orientations in different regions, optimizing both touch detection sensitivity and optical performance locally rather than using a uniform pattern throughout

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8947391B1Line spacing in mesh designs for touch sensors

Publication Date: 2015.02.03 BOE TECHNOLOGY GROUP CO LTD

AI summary

In one embodiment, an apparatus includes a touch sensor that includes a mesh of conductive material configured to extend across a display that includes multiple pixels that each include sub-pixels and dead space. The mesh includes multiple first and second lines of conductive material. The first lines are substantially parallel to each other, and the second lines are substantially parallel to each other. Each of the sub-pixels includes a color element separated from adjacent sub-pixels by dead space. 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 substantially perpendicular to the first axis. The first pixel pitch is a distance between corresponding features of two adjacent pixels along the first axis, and the second pixel pitch is a distance between corresponding features of two adjacent pixels along the second axis.