Liquid Crystal Display Subpixel Electrodes Photo-Alignment
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Solution Overview
Problem
Liquid crystal displays with vertical alignment (VA) mode face challenges in achieving wide viewing angles and high contrast ratios due to domain formation methods, which degrade aperture ratio, response speed, and cause momentary afterimages and blurry images due to random motion of liquid crystals and textures at domain boundaries.
Innovation Solution
A liquid crystal display design featuring pixel electrodes with subpixel electrodes and a shielding member that overlaps the boundaries of these electrodes, allowing for photo-alignment and differential voltage application to align liquid crystals in multiple domains, thereby improving visibility and reducing yellowish effects by controlling alignment directions and textures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a cutout portion is formed in a field generating electrode to form multiple domains, then liquid crystal alignment in vertical directions is improved, but aperture ratio is degraded
Solution Approach 1:
The pixel electrode is divided into multiple subpixel electrodes (first subpixel electrode and second subpixel electrode) that are supplied with different data voltages. This segmentation creates multiple domains within a single pixel, allowing liquid crystal molecules to align in different directions simultaneously, thereby achieving wide viewing angle characteristics without requiring physical cutout portions in the electrode structure.
Solution Approach 2:
Different regions of the pixel electrode are assigned different voltage levels through the subpixel electrode structure. The first subpixel electrode receives a first data voltage while the second subpixel electrode receives a second data voltage, creating local variations in electric field strength that induce different liquid crystal alignment directions in different regions, achieving domain formation without structural cutouts.
2Manufacturing precision
If a cutout portion is formed in a field generating electrode to form multiple domains, then liquid crystal alignment in vertical directions is improved, but response speed is degraded due to random motion
Solution Approach 1:
The patent applies dynamic voltage control to the subpixel electrodes, where the first and second data voltages are adjusted in real-time based on gray level requirements. By dynamically varying the voltage difference between subpixel electrodes, the liquid crystal molecules can transition smoothly between different alignment states, eliminating random motion and improving response speed while maintaining proper alignment.
3Area of stationary object
If photo-alignment method is used to form multiple domains, then aperture ratio is improved, but textures are generated at domain boundaries impairing transmittance
Solution Approach 1:
The patent controls the voltage parameters applied to subpixel electrodes to optimize domain formation. By carefully selecting the magnitude and relationship between the first and second data voltages, the electric field distribution is optimized to create smooth transitions between domains, minimizing texture formation at boundaries while maintaining high aperture ratio through the photo-alignment process.
4Manufacturing precision
If different luminance levels are used for each gray level of gamma curve, then yellowish effect occurs at intermediate gray levels, but image clarity is improved
Solution Approach 1:
The patent applies different voltage levels to different subpixel electrodes to compensate for the yellowish effect. By locally adjusting the electric field strength in different regions (first subpixel electrode vs. second subpixel electrode), the liquid crystal alignment angles are optimized for each region, allowing independent control of luminance characteristics to eliminate yellowish discoloration while maintaining overall image clarity.
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 lateral visibility and prevents yellowish effects by aligning liquid crystals in multiple domains with differential voltages and shielding textures, resulting in improved image clarity and reduced momentary afterimages.
Implementation Method 1
an alignment layer formed on at least one of the plurality of pixel electrodes and the common electrode and subjected to photo-alignment
Implementation Method 2
The electrodes generate an electric field in the liquid crystal layer by receiving voltages, thereby determining the orientation of liquid crystal molecules of the liquid crystal layer
Data Source
AI summary
Provided is a liquid crystal display including a first substrate and a second substrate facing each other, a plurality of pixel electrodes formed on the first substrate and each including a first subpixel electrode and a second subpixel electrode, a common electrode formed on the second substrate, a shielding member formed on the first substrate or the second substrate and overlapping a portion of the first subpixel electrode, an alignment layer formed on at least one of the plurality of pixel electrodes and the common electrode and subjected to photo-alignment, and a liquid crystal layer interposed between the first substrate and the second substrate.