Liquid Crystal Display Pixel Orientation Control
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Solution Overview
Problem
Liquid crystal display devices, particularly VA liquid crystal displays, suffer from viewing angle dependency and display quality issues due to unpredictable tilt directions of liquid crystal molecules and random disclination lines within pixel regions, leading to non-uniformity and degradation in display quality.
Innovation Solution
The implementation of an additional orientation controller within the pixel region, specifically at the center of the longest edge or as a cutout portion of the electrode, to stabilize the alignment direction and prevent random disclination lines, enhancing the control over liquid crystal alignment and improving display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If liquid crystal molecules are allowed to tilt freely in VA liquid crystal displays, then the initial vertical alignment is achieved, but the tilt direction becomes unpredictable leading to random disclination lines and non-uniformity in pixel regions
Solution Approach 1:
The pixel region is divided into multiple alignment regions by introducing orientation controllers (projections or cutout portions) that segment the liquid crystal alignment directions. This segmentation prevents random disclination lines by creating controlled alignment zones with specific tilt directions, resolving the contradiction between vertical alignment stability and alignment uniformity.
Solution Approach 2:
Different regions within the pixel are given different alignment properties through the orientation controllers. The projections or cutout portions create localized areas with specific alignment characteristics, ensuring that each region has controlled tilt directions rather than random tilting, thus improving overall alignment uniformity while maintaining vertical alignment stability.
2Device complexity
If no additional orientation controller is provided, then the device structure remains simple, but random disclination lines occur leading to degradation in display quality
Solution Approach 1:
Orientation controllers (projections or cutout portions) are incorporated into the electrode structure during the manufacturing process to pre-establish controlled alignment directions. This preliminary action prevents random disclination lines before they can form, improving display quality without requiring complex additional components, thus resolving the contradiction between structural simplicity and display quality.
3Speed
If the alignment direction is not stabilized, then the liquid crystal can respond quickly to voltage changes, but viewing angle dependency increases and display quality degrades
Solution Approach 1:
The orientation controllers create localized alignment regions with controlled tilt directions that stabilize the overall alignment. This local control of alignment quality improves viewing angle performance and reduces display quality degradation while maintaining fast response characteristics, resolving the contradiction between response speed and viewing angle performance.
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 solution effectively inhibits the occurrence of random disclination lines and improves display quality by stabilizing the alignment direction within the pixel region, thereby enhancing the viewing angle and responsiveness of the liquid crystal display.
Implementation Method 1
an alignment film to which a rubbing process is applied is formed on a contact surface, which faces the liquid crystal, of each of the pair of substrates
Implementation Method 2
the TN liquid crystal which has a positive dielectric constant anisotropy is initially aligned such that the major axis of the molecules is aligned along the direction of rubbing of the alignment film
Implementation Method 3
the linearly polarized light entering the liquid crystal layer through a polarizer plate on the side of the substrate placed near a light source becomes, in the liquid crystal layer which is aligned with the twist of 90°, linearly polarized light having the polarization axis different by 90°
Data Source
AI summary
An orientation controller which divides a pixel into a plurality of different priority alignment regions and an additional orientation controller are provided in a pixel. The additional orientation controller is provided at least at an end of a pixel of a long-side alignment region formed along the long side of the pixel among the divided alignment regions, for example, around a center position of the long side of the pixel. The additional orientation controller can be realized, for example, by forming a cutout pattern in a side of a first electrode (pixel electrode) forming a part of the pixel. Because the alignment direction is also controlled by the additional orientation controller, the alignment of liquid crystal in this region is stabilized.