Capacitive Touch Display Electrode Asymmetry to Reduce Moire
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Solution Overview
Problem
Display devices with touch detection capabilities using the electrostatic capacitance method experience interference fringes, or moire, particularly when displaying colors, due to differences in transmittance between areas with and without detection electrodes, which can lead to reduced image quality.
Innovation Solution
A display device design that includes a detection electrode and a conductive pattern on an insulating substrate, with a specific arrangement of subpixel regions and detection electrodes to reduce moire interference by ensuring that the array direction of subpixel regions and detection electrode patterns cross each other, thereby minimizing transmittance differences and preventing specific colors from being highlighted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If detection electrodes are arranged in a matrix form with polygonal holes, then touch detection capability is improved, but transmittance differences cause moire interference to worsen
Solution Approach 1:
The patent applies asymmetry by arranging green subpixels in a non-uniform pattern within the pixel matrix. Specifically, green subpixels are positioned at corners and edges rather than in a regular grid, creating an asymmetric distribution that disrupts the periodicity causing moire. The detection electrode patterns are also designed with asymmetric hole arrangements that differ from conventional symmetric matrices, thereby reducing interference while preserving touch detection functionality.
2Illumination intensity
If green subpixels are concentrated on high transmittance parts, then luminance is improved, but moire interference is generated
Solution Approach 1:
The patent applies local quality by varying the transmittance characteristics of detection electrodes in different regions of the display. Detection electrodes in regions with green subpixels have different hole patterns and transmittance values compared to other regions, allowing optimal luminance for green subpixels while preventing moire interference through localized transmittance adjustment.
Solution Approach 2:
The patent changes physical parameters of detection electrodes, specifically adjusting hole size, shape, and distribution patterns in different regions. By modifying these parameters locally, the patent achieves high luminance for green subpixels on high transmittance parts while disrupting the periodic patterns that cause moire interference.
3Measurement precision
If detection electrode patterns are arranged to improve touch detection, then detection precision is improved, but image quality deteriorates due to moire
Solution Approach 1:
The patent segments the detection electrode structure into multiple functional regions with different hole patterns. By dividing the detection electrode into regions with varying transmittance and pattern densities, the patent maintains high detection precision in touch-sensitive areas while reducing moire interference in display-critical regions, thereby improving overall image quality.
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 reduces the generation of moire interference, improving image quality and brightness by dispersing the same color subpixel regions and adjusting the pattern arrangement to prevent overlapping and highlight issues, while also optimizing pixel and pattern pitches for enhanced performance.
Implementation Method 1
An electrostatic capacitance method has been known as a method of detecting the touch of the external object. In the touch detection function-equipped display device of the electrostatic capacitance method, a detection electrode is arranged so as to cross a drive electrode. A capacitance is formed at a crossing portion of the drive electrode and the detection electrode, the amount of charge stored in the capacitance of the crossing portion is changed when an external object such as a finger touches this crossing portion, and the change of the amount of charge is detected to detect the touch of the external object.
Data Source
AI summary
The display device includes a detection electrode, a display pattern, a detection circuit connected to the detection electrode, a plurality of subpixel regions in which pixel electrodes are formed, pixel regions each composed of the subpixel regions, and a display region in which the pixel regions are arrayed. The pixel regions each include a first color subpixel region and a second color subpixel region. The subpixel regions are arrayed in a Y direction in the display region. First patterns having a circular or polygonal shape in a plan view are formed in the detection electrode. The detection electrode includes a first region electrically connected to the detection circuit and a second region separated from the detection circuit inside the display region. The first region extends in an X direction and a virtual line connecting centers of the adjacent first patterns extends in the X direction.