Irregular Electrode Wire Pattern for Touch Panel Moire Suppression
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Solution Overview
Problem
The existing touch panel electrode structures using metal wires for electrostatic capacitance detection suffer from moire and graininess issues due to periodicity mismatches between electrode wire patterns and pixel patterns, leading to image quality deterioration.
Innovation Solution
An electrode structure with irregularly bent electrode wires, maintaining low periodicity to suppress moire and graininess, achieved by adjusting the gap proportion between electrode wires and using evaluation values to ensure optimal spectral density, thereby reducing the visibility of periodic structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a grid-shaped periodic structure is used for electrode wires, then the electrode wire pattern is easy to form and manufacturing is simple, but moire is observed when overlaid on the pixel pattern, causing image quality deterioration
Solution Approach 1:
The patent applies asymmetry by replacing the symmetric grid-shaped periodic structure with asymmetric irregular bent line shapes. The electrode wires are designed with random bending and non-uniform spacing, breaking the periodic symmetry that causes moire. This asymmetric design eliminates the regular repeating pattern that interacts with the pixel grid to produce moire, while still maintaining electrical functionality.
Solution Approach 2:
The patent changes the geometric parameters of the electrode wire pattern from a regular grid structure to irregular bent lines with variable spacing and orientation. By randomizing the position, shape, and orientation of electrode wires, the periodicity parameter is fundamentally altered, transforming the pattern from high-regularity (grid) to low-regularity (irregular), thereby suppressing moire formation.
2Object-affected harmful factors
If the periodicity of the electrode wire pattern is reduced to suppress moire, then moire observation is suppressed, but graininess is generated in the display device
Solution Approach 1:
The patent applies local quality by allowing different regions of the electrode wire pattern to have different local characteristics. While the overall pattern maintains low periodicity to suppress moire, local clustering and spacing of electrode wires are optimized to maintain sufficient signal strength. This localized optimization ensures that reducing global periodicity doesn't uniformly degrade performance, as local density variations compensate for the reduced overall regularity.
Solution Approach 2:
The patent creates a composite electrode wire pattern that combines multiple characteristics: irregular bent line shapes for moire suppression, strategic clustering for signal maintenance, and optimized spacing for graininess control. This composite approach integrates conflicting requirements into a unified pattern design that simultaneously achieves moire suppression and graininess minimization.
3Object-affected harmful factors
If irregular bent line shapes are used for electrode wires, then moire is suppressed by reducing periodicity, but the formation precision of electrode wire shapes becomes difficult to control
Solution Approach 1:
The patent applies preliminary action by establishing a reference pattern with predetermined characteristics before generating the final irregular electrode wire pattern. The reference pattern serves as a template that guides the formation process, ensuring that even though the final pattern is irregular, it maintains controlled characteristics through systematic deviation from the reference. This preliminary reference structure enables precise control over the irregularities.
Solution Approach 2:
The patent implements feedback mechanisms in the electrode wire formation process, where the actual formed pattern is measured and compared against target specifications. Adjustment parameters are modified based on measurement results to ensure that the irregular bent line shapes achieve the desired low periodicity for moire suppression while maintaining formation precision within acceptable tolerances. This closed-loop control enables precise control of complex irregular geometries.
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
The solution effectively suppresses moire and graininess, maintaining image quality by ensuring the electrode wire pattern's periodicity is low enough to avoid interference with pixel patterns, while allowing precise formation of electrode wire shapes.
Implementation Method 1
An electrostatic capacitance method, in which contact of a finger or the like with an operating surface of the touch panel is detected as a change in electrostatic capacity
Implementation Method 2
In a form in which the electrode wires comprise a metal which absorbs or reflects visible light
Implementation Method 3
In a form in which the electrode wires comprise a metal which absorbs or reflects visible light
Data Source
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AI summary
[Problem] The problem addressed by the present invention lies in providing a conductive film, a touch panel and a display device which make it possible to suppress a deterioration in the quality of images observed on the display device. [Solution] In a power spectrum obtained by means of a two-dimensional Fourier transform of each of an electrode wire pattern formed from electrode wires which bend irregularly and a reference pattern formed by regular bent lines, a value obtained by dividing, at predetermined frequency widths, the cumulative value of spectral intensity of each frequency width by the frequency width is a spectral density, and a first evaluation value, which is a common logarithm of a value obtained by dividing the cumulative value of the spectral density in a defined frequency region of the electrode wire pattern by the cumulative value of the spectral density in a defined frequency region of the reference pattern, is 3.6 or less.