FFS Liquid Crystal Display Electrode Segmentation for Reverse Twist Domain Control
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Solution Overview
Problem
FFS mode liquid crystal display panels face issues with reverse twist domains, leading to decreased aperture ratio and display quality due to the occurrence of abnormal alignment and ripple problems when a force is applied to the surface.
Innovation Solution
The design includes a pair of substrates with a liquid crystal layer, where pixel areas have upper electrodes with slit-shaped openings and a lower electrode formed through an insulation layer, with areas where the lower electrode does not exist, creating a predetermined angle with the rubbing direction of the alignment film, which reduces the electric field strength and minimizes reverse twist domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the lower electrode is formed continuously in portions overlapping with ends of slit-shaped openings of the upper electrode, then the electrode structure is simplified and manufacturing is easier, but reverse twist domains occur leading to decreased aperture ratio and display quality
Solution Approach 1:
The lower electrode is segmented into multiple regions: a first region that overlaps with the slit-shaped openings of the upper electrode, and a second region that does not overlap with the ends of the slits. This segmentation prevents reverse twist domains at the electrode ends while maintaining electrical connectivity and simplified manufacturing processes.
Solution Approach 2:
Different regions of the lower electrode are designed with different properties: the first region provides electrical connection and field generation, while the second region is specifically designed to avoid overlap with slit ends to prevent reverse twist domains. This local differentiation resolves the contradiction between manufacturing simplicity and display quality.
2Manufacturing precision
If light-shielding structures are added to prevent reverse twist domains, then display quality improves, but the aperture ratio decreases due to additional light-blocking areas
Solution Approach 1:
The harmful overlap region between the lower electrode and the ends of upper electrode slits is extracted and eliminated. By designing the lower electrode to not overlap with these specific regions, reverse twist domains are prevented without requiring additional light-shielding structures, thus maintaining a high aperture ratio while improving display quality.
3Area of stationary object
If the lower electrode overlaps with the ends of slit-shaped openings, then the electrode area is maximized for better electrical performance, but abnormal alignment and ripple problems occur when force is applied to the surface
Solution Approach 1:
The lower electrode is divided into functional regions where the overlap with slit ends is eliminated in specific areas. This segmentation maintains sufficient electrode area for electrical performance while removing the problematic overlap regions that cause abnormal alignment and ripple issues under mechanical stress.
Solution Approach 2:
The lower electrode design incorporates local quality variations: regions overlapping with slit openings provide electrical function, while regions avoiding overlap with slit ends provide mechanical stability and prevent alignment abnormalities under applied force.
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
This configuration enhances the aperture ratio and display quality by preventing reverse twist domains and allowing for a brighter display without the need for light-shielding, thus improving the overall performance of the FFS mode liquid crystal display panel.
Implementation Method 1
an alignment film formed close to the liquid crystal layer... A longitudinal direction of the plurality of slit-shaped openings and a rubbing direction of the alignment film form a predetermined angle
Implementation Method 2
when an electric field is generated between each of the pixel electrodes 78 and each of the counter electrodes 75, the electric field is oriented from both sides of the pixel electrode 78 toward the counter electrode 75
Implementation Method 3
An operation principle of the FFS mode liquid crystal display panel of the in-plane switching mode liquid crystal display panel
Implementation Method 4
Liquid crystal LC is sealed between the array substrate AR and the color filter substrate CF... when an electric field is generated between each of the pixel electrodes 78 and each of the counter electrodes 75
Data Source
AI summary
A liquid crystal display panel includes a pair of substrates opposed to each other with a liquid crystal layer interposed therebetween. In the liquid crystal display panel, a plurality of pixel areas are formed in one of the pair of substrates and each of the pixel areas is provided with an upper electrode having a plurality of slit-shaped openings, a lower electrode formed in the substrate through the upper electrode and an insulation layer, and an alignment film formed close to the liquid crystal layer. A longitudinal direction of the plurality of slit-shaped openings and a rubbing direction of the alignment film form a predetermined angle therebetween. In addition, in the lower electrode, areas where the lower electrode does not exist are formed in portions in which ends of the slit-shaped openings of the upper electrode overlap with the lower electrode in plan view.