LCD Pixel Electrode Convex Portions for Aperture Ratio and Disclination Control
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Solution Overview
Problem
Conventional horizontal electric field type LCDs face issues with reduced aperture ratio, display unevenness, and the need for high voltage due to oblique electrode orientations, which lead to disclination and light leakage, and existing solutions either increase the risk of opposite rotation or do not effectively control liquid crystal rotation direction.
Innovation Solution
A liquid crystal display device with a pixel electrode and counter electrode substrate where convex or concave portions with a long and narrow shape are used to control the rotation direction of liquid crystal molecules, allowing the initial alignment direction to be parallel or perpendicular to the electric field, thereby increasing aperture ratio and reducing disclination risk while operating at lower voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the extension direction of pixel electrodes and counter electrodes is oriented obliquely with respect to the initial alignment direction to specify liquid crystal rotation direction, then the rotation direction can be controlled, but the aperture ratio is reduced due to complicated pixel shapes
Solution Approach 1:
The invention introduces protrusions or recesses at specific local regions (edge portions) of the pixel electrodes and counter electrodes. These localized structural modifications create asymmetric electric field distributions only at the critical edge regions, enabling rotation direction control without requiring oblique orientation of the entire electrode structure. This preserves the rectangular pixel shape and maintains high aperture ratio.
Solution Approach 2:
Instead of controlling rotation direction through in-plane oblique orientation (2D plane rotation), the invention uses vertical dimension structural features (protrusions/recesses extending from the electrode surface) to create asymmetric electric fields. This dimensional transition allows perpendicular electrode orientation while maintaining rotation direction control through the asymmetric edge structures.
2Reliability
If the extension direction of pixel electrodes and counter electrodes is oriented obliquely with respect to the initial alignment direction, then liquid crystal rotation direction can be specified, but display unevenness occurs due to disclination at boundary regions
Solution Approach 1:
The asymmetric protrusions or recesses are placed only at the edge portions of the electrodes, creating localized asymmetric electric fields precisely where disclination occurs. This targeted approach stabilizes the liquid crystal alignment at critical boundary regions without affecting the overall uniformity of the pixel interior, thereby preventing display unevenness while maintaining rotation direction control.
Solution Approach 2:
The protrusions or recesses are pre-formed on the electrode structures before liquid crystal alignment occurs. These pre-existing asymmetric features guide the liquid crystal molecules during the alignment process, preventing disclination formation from the outset rather than correcting it afterward. This preliminary structural guidance ensures uniform display characteristics.
3Reliability
If the extension direction of pixel electrodes and counter electrodes is oriented obliquely with respect to the initial alignment direction, then liquid crystal rotation direction can be specified, but high voltage is required for efficient rotation
Solution Approach 1:
The asymmetric protrusions or recesses concentrate the electric field strength at specific edge regions where they are located. This localized field enhancement creates stronger effective torques on the liquid crystal molecules at critical positions, improving rotation efficiency and reducing the overall voltage required to achieve the desired alignment state.
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 solution enhances the aperture ratio, suppresses disclination, and allows efficient liquid crystal rotation at lower voltages, reducing the likelihood of opposite rotation and light leakage, while maintaining control over the rotation direction.
Implementation Method 1
light transmittance is controlled by applying an electric field between pixel electrodes to rotate liquid crystal molecules
Implementation Method 2
rotate liquid crystal molecules from an initial alignment direction
Implementation Method 3
convex or concave portions with a long and narrow shape whose longitudinal direction has an oblique angle with respect to an initial alignment direction of the liquid crystal molecules
Implementation Method 4
initial alignment direction of the liquid crystal molecules is parallel to an extension direction of at least one of the pixel electrode and the counter electrode
Data Source
AI summary
A liquid crystal display device includes a pixel electrode substrate including a pixel electrode and a counter electrode formed thereon; a counter substrate provided to face the pixel electrode substrate; and a liquid crystal interposed between the pixel electrode substrate and the counter substrate, the liquid crystal display device being of a mode that rotates liquid crystal molecules substantially in parallel to the pixel electrode substrate. In the display device, an initial alignment direction of the liquid crystal molecules is parallel to an extension direction of at least one of the pixel electrode and the counter electrode, and a pixel includes at least one convex portion or concave portion that has a long and narrow shape and whose longitudinal direction has an oblique angle with respect to the initial alignment direction of the liquid crystal molecules in the same direction as a desired liquid crystal rotation direction.