Rhombus-like Pixel Electrode for LCD Transmittance and Viewing Angle
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Solution Overview
Problem
Liquid crystal displays (LCDs) face challenges in achieving high transmittance and wide viewing angles while maintaining response speed and display quality, particularly in vertical alignment (VA) mode LCDs.
Innovation Solution
The design incorporates a pixel electrode with a rhombus-like plate portion and minute branch portions on the lower panel, and a domain dividing element with cross-shaped openings on the common electrode, creating a fringe field that influences liquid crystal alignment and enhances transmittance and viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional alignment aids are used to control liquid crystal alignment, then liquid crystal alignment can be achieved, but transmittance is reduced and viewing angles are limited
Solution Approach 1:
The invention removes conventional alignment aids (such as alignment layers or rubbing structures) from the display device. Instead, it uses the electrode structures themselves (pixel electrode with rhombus-like plate portion and minute branch portions, and common electrode with domain dividing elements) to generate electric fields that directly control liquid crystal alignment, thereby eliminating the need for separate alignment components and increasing light transmittance.
Solution Approach 2:
The electrode structures serve dual functions: they generate the electric field necessary for pixel operation and simultaneously provide the alignment control function traditionally performed by separate alignment aids. The rhombus-like plate portion and domain dividing elements create specific electric field patterns that induce pretilting and domain formation without requiring additional alignment layers.
2Illumination intensity
If multiple domains are formed in one pixel to achieve wide viewing angles, then viewing angles improve, but response speed decreases
Solution Approach 1:
The invention creates different local alignment conditions within a single pixel by forming multiple domains with different inclination directions. The rhombus-like plate portion and domain dividing elements generate localized electric field patterns that induce different pretilting angles and orientations in different regions of the pixel, enabling wide viewing angles while maintaining fast response through optimized local alignment.
Solution Approach 2:
The electrode structures are designed to induce preliminary pretilting of liquid crystal molecules in specific directions before the main switching operation. The minute branch portions and domain dividing elements create initial alignment patterns that reduce the time required for liquid crystal reorientation during switching, thereby improving response speed while maintaining multiple domains for wide viewing angles.
3Illumination intensity
If electrode structures are optimized to increase transmittance, then light transmission improves, but liquid crystal alignment control becomes difficult
Solution Approach 1:
The invention uses asymmetric electrode structures, specifically the rhombus-like plate portion with outwardly bowed sides and the domain dividing elements with specific geometric configurations, to generate non-uniform electric field patterns. These asymmetric structures create well-defined electric field gradients that provide precise alignment control while maximizing the active area for light transmission.
Solution Approach 2:
The rhombus-like plate portion features outwardly bowed sides with centers that coincide with reference sides, creating curved electric field distributions. This curvature in the electrode geometry helps to evenly distribute the electric field and induce uniform pretilting across different regions, maintaining alignment control precision while allowing for larger electrode areas that increase 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
This configuration increases transmittance and viewing angles, improving display quality and response speed by optimizing the electric field and liquid crystal alignment without the need for conventional alignment aids.
Implementation Method 1
an image is displayed by changing the transmittance of light though various regions. The transmittance of light is controlled by altering an alignment of liquid crystal molecules using an electric field which is created by applying different voltages to pixel and common electrodes
Implementation Method 2
The plurality of domains may be embodied by forming various features, for example, cutouts and the like, in the pixel electrode and/or the common electrode. Then, a fringe field may be generated between edges of the cutouts and electrodes facing them. LCDs may utilize an initial alignment method in which the liquid crystal molecules are pretilted when no electric field is present. This pre-tilting may increase response speed while maintaining a wide viewing angle
Data Source
AI summary
A liquid crystal display includes a lower panel, an upper panel, and a liquid crystal layer disposed therebetween. The lower panel includes a pixel electrode including at least one unit pixel electrode. The upper panel includes a common electrode. The unit pixel electrode includes a rhombus-like plate portion, and a plurality of minute branch portions extending therefrom.