Subpixel Structure Suppressing White Touch Mura in In-Cell Displays
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Solution Overview
Problem
In-cell type display devices and in-plane switching (IPS) mode liquid crystal display devices are prone to white touch mura defects and decreased transmittance due to the alignment of liquid crystals being disrupted by external pressure, which cannot be rapidly restored, and existing solutions to improve touch mura often compromise image quality.
Innovation Solution
A subpixel structure with concavo-convex patterns on the pixel electrode area, including a common electrode with slit structures and pixel electrodes with multiple spaces, is implemented to suppress white touch mura and transmittance loss by enhancing the restoration force of liquid crystals and optimizing the angle between the pixel electrode and liquid crystal alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a common electrode is located on a pixel electrode in an in-cell type display device, then touch sensing function is provided, but white touch mura defect occurs due to liquid crystal alignment disruption by external pressure
Solution Approach 1:
The pixel electrode is divided into multiple segments (first pixel electrode and second pixel electrode) separated by a first gap, and the common electrode is divided into multiple segments (first common electrode and second common electrode) separated by a second gap. This segmentation reduces the continuous contact area between electrodes, thereby reducing the impact of external pressure on liquid crystal alignment and suppressing white touch mura while maintaining touch sensing functionality.
2Reliability
If existing technologies are used to improve white touch mura, then touch mura is reduced, but additional image quality defects such as decrease in brightness of each subpixel occur
Solution Approach 1:
The invention applies different gap sizes at different locations: a first gap between pixel electrodes and a second gap between common electrodes. By optimizing the local gap dimensions, the liquid crystal alignment is improved in the touch pressure area (reducing white touch mura) while maintaining adequate light transmission in the display area (preserving brightness), thus avoiding the trade-off present in conventional approaches.
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 subpixel structure effectively reduces white touch mura defects and maintains transmittance by increasing the restoration force of liquid crystals, preventing image quality degradation and ensuring rapid alignment recovery upon external pressure, such as touch input.
Implementation Method 1
a pixel electrode disposed in the subpixel area; and a common electrode disposed to be overlapped with the pixel electrode with a protective layer interposed therebetween
Implementation Method 2
the alignment of liquid crystals is changed by an external pressure such as a touch but cannot be rapidly restored
Data Source
AI summary
There are provided a subpixel structure of a display device and a touch screen-integrated display device, including: a plurality of gate lines; a plurality of data lines configured to define subpixels by intersecting with the gate lines; a thin-film transistor; a pixel electrode disposed in the subpixel area; and a common electrode disposed to be overlapped with the pixel electrode with a protective layer interposed therebetween. The pixel electrode has patterns including a plurality of pixel electrode spaces in an area corresponding to the thin-film transistor so as to suppress a white touch mura defect and also suppress a decrease in transmittance occurring at an interface between an open area and a BM area.