Pixel Electrode Slit Patterns for VA LCD Transmittance
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Solution Overview
Problem
Vertically aligned mode liquid crystal display devices face reduced transmittance due to uncontrolled liquid crystal molecules in fringe fields, leading to gray or black points in viewing, which affect the display's overall visibility and contrast ratio.
Innovation Solution
The display device incorporates pixel electrodes with specific slit patterns and branch electrodes on both substrates, including central and outer slits, to control liquid crystal alignment and prevent collisions, thereby improving transmittance and side visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a vertically aligned mode liquid crystal display device uses fine slits and opened patterns to form multiple domains, then viewing angle is improved, but transmittance is reduced due to uncontrolled liquid crystal molecules in fringe fields
Solution Approach 1:
The patent applies different slit configurations to different regions of the pixel electrode. Central slits are positioned in the center area while control slits are positioned in outer areas adjacent to connection sides. This local differentiation allows central slits to control liquid crystal alignment for wide viewing angles, while control slits specifically manage fringe field effects at boundaries to maintain transmittance, thus resolving the contradiction between viewing angle and transmittance.
Solution Approach 2:
The pixel electrode is segmented into multiple functional regions with different slit types. The electrode includes a central electrode portion with central slits for domain formation, and outer areas with control slits for fringe field control. This segmentation allows each region to perform its specific function optimally, enabling both wide viewing angle and high transmittance simultaneously.
2Illumination intensity
If multiple domains are formed using fine slits in pixel electrodes, then side visibility is improved, but gray or black points appear due to uncontrolled liquid crystal alignment
Solution Approach 1:
Control slits act as intermediary elements between the central slits and the connection sides. These control slits mediate the liquid crystal alignment in the outer areas, ensuring smooth transition and preventing abrupt alignment changes that cause gray or black points. The control slits provide intermediate control in the fringe field regions, maintaining alignment stability while preserving side visibility.
Solution Approach 2:
The patent changes the slit configuration parameters in different regions. Control slits in outer areas have specific width and spacing parameters optimized for fringe field control, while central slits have parameters optimized for domain formation. By adjusting these parameters locally, the patent achieves stable liquid crystal alignment throughout the pixel electrode, eliminating gray or black points while maintaining side visibility.
3Manufacturing precision
If connection sides are made longer to connect pixel electrodes, then manufacturing precision is improved, but liquid crystal molecule collisions increase reducing display quality
Solution Approach 1:
Control slits are pre-positioned in outer areas adjacent to connection sides before the liquid crystal is filled. These control slits prepare the electric field distribution in advance to guide liquid crystal alignment along the connection sides. By establishing the alignment pattern beforehand, the patent prevents liquid crystal molecule collisions during the filling process, maintaining both manufacturing precision and display quality.
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 design enhances transmittance and side visibility by adjusting liquid crystal molecule alignment, reducing texture phenomena and maintaining high contrast ratios across various viewing angles.
Implementation Method 1
The liquid crystal display device may form an electric field in the liquid crystal layer by applying a voltage to an electrode for generating the electric field
Implementation Method 2
The electric field may determine an alignment direction of liquid crystal molecules of the liquid crystal layer
Implementation Method 3
control polarization of incident light to display an image
Data Source
AI summary
A display device including a first substrate including pixel electrodes arranged in first and second directions, each pixel electrode including a unit pixel electrode, a second substrate including a common electrode on which an opening pattern is formed, and a liquid crystal layer disposed between the first substrate and the second substrate. The unit pixel electrode includes a central electrode portion including diagonal sides, connection sides, a cross slit extending in the first and second directions, and central branch slits extending from the cross slit, and a branch electrode portion including branch electrodes protruding from each of the diagonal sides, in which the connection sides includes first and second connection sides extending in the first and second directions, and the central electrode portion has first outer areas adjacent to the first connection sides and on which first control slits extending in the first direction are respectively formed.