Thin-Film Transistor Substrate Slits for Uniform Electric Fields
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Solution Overview
Problem
FFS liquid crystal displays suffer from non-uniform electric fields due to differences in alignment layer resistance, leading to afterimage and flicker defects caused by residual DC components, which are more pronounced in edge areas.
Innovation Solution
A thin film transistor substrate design with specific slit configurations and a floating conductive layer or common electrode slits to ensure uniform electric field distribution by aligning the resistance and residual DC components across inner and edge areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the distance between pixel electrodes is reduced to create a fringe field, then aperture ratio and transmittance are improved, but non-uniform electric fields occur due to differences in alignment layer resistance between inner and edge areas
Solution Approach 1:
The patent introduces slits at specific locations (edge areas) of the pixel electrode to locally modify the alignment layer resistance. This creates different structural characteristics in different regions: the edge areas with slits have modified resistance properties compared to the inner areas, thereby compensating for the inherent resistance differences and achieving uniform electric field distribution across the display panel.
2Reliability
If the alignment layer resistance differs between inner and edge areas, then residual DC components become non-uniform, but this causes afterimage and flicker defects
Solution Approach 1:
The patent changes the physical structure of the alignment layer by introducing slits, which modifies the electrical resistance parameter in the edge areas. This parameter change (resistance modification through structural alteration) balances the residual DC components across different regions, preventing the generation of afterimage and flicker defects that would otherwise occur due to non-uniform resistance distribution.
3Reliability
If slits are introduced to modify alignment layer resistance, then uniform electric field distribution is achieved, but device structure becomes more complex
Solution Approach 1:
The patent divides the alignment layer structure by introducing slits that segment the continuous alignment layer into distinct regions. These slits create separate pathways for electrical conduction, effectively modifying the resistance distribution without requiring complete restructuring of the entire device. This segmentation approach achieves uniform electric field distribution while maintaining manufacturing feasibility.
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
Prevents afterimage and flicker defects by ensuring rapid dissipation of residual DC components, enhancing display quality.
Implementation Method 1
A Liquid Crystal Display (LCD) is a display apparatus that acquires a desired image signal by applying an electric field to a liquid crystal layer, which is introduced between a Thin Film Transistor (TFT) substrate and a color filter substrate and has anisotropic dielectric permittivity
Implementation Method 2
dopants in the liquid crystal layer are ionized to thereby become adsorbed on the alignment layer 26. That is, positive ions are absorbed on the alignment layer 26 that corresponds to a minus (−) electrode, and negative ions are adsorbed on the alignment layer 26 that corresponds to a plus (+) electrode
Implementation Method 3
As the ions adsorbed on the alignment layer 26 are diffused to the liquid crystal layer, a residual DC voltage is generated
Data Source
AI summary
Disclosed is a display device having a thin film transistor substrate, which may prevent afterimage and flicker defects by reducing the non-uniformity of an electric field. In the thin film transistor substrate, a pixel electrode includes a transparent edge electrode and a transparent inner electrode, which are spaced apart from each other with a first slit having a first width interposed therebetween, and a common electrode is exposed from the other-side end of the transparent edge electrode by a second width, which is smaller than the first width, in the width direction of a data line. As such, an inner area and an edge area in each sub pixel have uniform electric field distribution.