LCD Pixel Electrode Segmentation for Lateral Visibility
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Solution Overview
Problem
Vertical alignment (VA)-mode LCD devices suffer from poorer lateral visibility compared to front visibility, with increased brightness when viewed from the sides, leading to deteriorated visibility as the brightness difference between front and side views increases.
Innovation Solution
A liquid crystal display device with a pixel electrode structure that includes a first stem electrode, a second stem electrode intersecting the first, a third stem electrode connected to the first, and a plurality of branch electrodes extending from these, along with a specific domain area arrangement on the substrate, which controls the tilt direction of liquid crystal molecules to improve visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional pixel electrode structure is used in a VA-mode LCD device, then the front visibility is maintained, but the lateral visibility deteriorates with increased brightness when viewed from the sides
Solution Approach 1:
The pixel electrode is divided into multiple stem electrodes (first, second, and third stem electrodes) with different orientations. The first stem electrode extends in a first direction, the second stem electrode extends in a second direction perpendicular to the first, and the third stem electrode extends in the second direction. This segmentation creates multiple domain areas that control liquid crystal molecule tilt directions, thereby improving lateral visibility by reducing the brightness difference between front and side views.
Solution Approach 2:
Different regions of the pixel electrode are designed with different stem electrode configurations to create specific domain areas. The first domain area is controlled by the first and second stem electrodes, the second domain area by the second and third stem electrodes, and additional domain areas by the third stem electrode and branch electrodes. This local quality variation allows precise control of liquid crystal orientation in different regions, improving overall lateral visibility.
2Illumination intensity
If the brightness difference between front and side views increases, then the VA-mode LCD device appears brighter when viewed from the sides, but the visibility deteriorates
Solution Approach 1:
The pixel electrode is segmented into multiple stem electrodes with different orientations to create multiple domain areas. This segmentation controls the tilt direction of liquid crystal molecules in different regions, resulting in more uniform brightness distribution when viewed from different angles, thereby improving visibility.
Solution Approach 2:
The second and third stem electrodes are divided into two halves by the first stem electrode, creating an asymmetric structure. This asymmetric design, combined with the specific arrangement of domain areas, helps control light transmission more uniformly across different viewing angles, reducing the brightness difference between front and side views.
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 improved electrode structure and domain area arrangement uniformly control the tilt of liquid crystal molecules, enhancing lateral visibility and minimizing the brightness difference between front and side views, thus improving overall visibility of the LCD device.
Implementation Method 1
The LCD device generates an electric field in the liquid crystal layer by applying voltages to the field-generating electrodes so as to determine the orientation of liquid crystal molecules in the liquid crystal layer
Implementation Method 2
displays an image by controlling the polarization of light incident thereupon using the electric field
Data Source
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AI summary
A liquid crystal display (LCD) device comprising: a substrate on which an active area that transmits light therethrough is defined; and a pixel electrode (180) disposed on the substrate, wherein the pixel electrode includes a first stem electrode (181), which extends along a first direction, a second stem electrode (182), which extends along a second direction that is perpendicular to the first direction and intersects the first stem electrode (181) to be divided into two halves by the first stem electrode (181), a third stem electrode (183), which extends along the second direction and is connected to the first stem electrode (181) to be divided into two halves by an end of the first stem electrode (181), and a plurality of branch electrodes (184), which extend from at least one of the first stem electrode (181), the second stem electrode (182) and the third stem electrode (183).