LCD Pixel Electrode Opening Prevents Disclination Lines
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Solution Overview
Problem
Conventional polymer stabilized alignment (PSA) LCD panels face issues with disclination lines at the edge of pixel electrodes, affecting contrast and transmittance, leading to mura defects in large display screens.
Innovation Solution
A pixel structure with an opening at the edge of the pixel electrode adjacent to data and scan lines, where a portion of the metal line is exposed, ensuring the shortest distance between the opening edge and the metal line is greater than or equal to 3 μm, preventing disclination lines and enhancing transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pixel structure without opening is used, then the structure is simple and manufacturing is easy, but disclination lines occur at the edge of the pixel electrode affecting contrast and transmittance
Solution Approach 1:
The pixel electrode is segmented by introducing an opening at its edge, dividing the continuous electrode structure into separate regions. This segmentation allows the liquid crystal material to be properly oriented in different areas, preventing disclination lines while maintaining structural integrity and manufacturing feasibility
Solution Approach 2:
The opening is strategically positioned at specific locations where disclination lines typically occur. By locally modifying the pixel electrode structure at these critical positions, the patent addresses the disclination problem without requiring complete redesign of the entire pixel structure, thus improving contrast and transmittance while minimizing structural complexity
2Reliability
If the opening is made larger to expose more metal line, then disclination lines are prevented, but the aperture ratio decreases and transmittance is reduced
Solution Approach 1:
The opening is designed to expose only the necessary portion of the metal line (at least 3 μm) to prevent disclination lines, rather than exposing the entire metal line or using a unnecessarily large opening. This partial action approach achieves the primary goal of preventing disclination while minimizing the impact on aperture ratio and maintaining optimal transmittance
3Device complexity
If the distance between opening edge and metal line is reduced, then the structure is more compact, but disclination lines may occur and transmittance deteriorates
Solution Approach 1:
The patent specifies a minimum distance parameter (at least 3 μm) between the opening edge and the metal line to prevent disclination lines and maintain transmittance. By establishing this critical parameter threshold, the patent achieves an optimal balance between structural compactness and performance, ensuring that the structure remains compact while preventing disclination and maintaining high transmittance
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 prevents disclination lines, improving transmittance and display quality by ensuring the liquid crystal material is tilted towards the center of the pixel structure, thereby maintaining high contrast and reducing mura defects.
Implementation Method 1
the liquid crystal material correspondingly placed at the opening of the each pixel structures is tilted toward a center of the pixel structure
Data Source
AI summary
A pixel structure and a liquid crystal display (LCD) panel having the same are provided. The pixel structure includes a data line, a scan line, at least one active device, a pixel electrode, and a metal line. The active device is electrically connected to the data line and the scan line. The pixel electrode is electrically connected to the active device and has an opening at the edge of the pixel electrode adjacent to at least one of the data line and the scan line. The metal line is located below the pixel electrode. Besides, a portion of the metal line extending to the edge of the pixel electrode is exposed by the opening. The shortest distance between an edge of the opening of the pixel electrode and the metal line is greater than or substantially equal to 3 μm.