VA LCD Multi-Domain Ribs Shift Dark Lines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
VA-mode liquid crystal display devices with multi-domain structures formed using alignment films suffer from alignment disturbances near pixel electrodes, leading to reduced display quality and transmittance due to dark lines appearing parallel to the edges, which lowers the overall display luminance.
Innovation Solution
A liquid crystal display device with a vertical alignment type liquid crystal layer, featuring a multi-domain structure where the tilt directions of liquid crystal domains are set to be approximately 90 degrees apart, and ribs are strategically placed near the edges of the pixel electrodes to shift the dark lines outward, improving transmittance by optimizing the position and alignment of these ribs relative to the edge portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If alignment films are used to define pretilt directions in VA-mode liquid crystal display devices, then viewing angle characteristics are improved, but alignment disturbance occurs near pixel electrode edges causing dark lines and reduced transmittance
Solution Approach 1:
A rib structure is introduced as an intermediary element between the pixel electrode and the liquid crystal layer. This rib acts as a mediator that modifies the electric field distribution and provides additional alignment regulation, preventing the dark line formation caused by direct alignment film-to-electrode interaction. The rib structure serves as a buffer zone that resolves the alignment disturbance at the electrode edges.
Solution Approach 2:
The alignment regulation is made non-uniform by introducing ribs only at specific locations where dark lines occur (near the edges of pixel electrodes), while maintaining uniform alignment films in the central region. This localized modification allows the rib structures to address alignment disturbances only where needed, preserving the overall alignment uniformity while eliminating edge effects.
2Adaptability or versatility
If slits or ribs are used as alignment regulation structures, then multi-domain structure is formed, but nonuniform alignment regulation force causes response speed distribution
Solution Approach 1:
Different alignment regulation mechanisms are applied to different regions: alignment films provide uniform pretilt definition in the central area, while ribs provide localized alignment regulation at the edges. This spatial differentiation allows each structure to optimize its function, with ribs specifically addressing edge alignment issues without disrupting the uniform response characteristics of the central region.
3Reliability
If slits or ribs are provided in or on electrodes, then alignment regulation force is exerted, but light transmittance is lowered in the area where they are provided
Solution Approach 1:
The rib structures are designed with optimized dimensions and positioning to minimize their impact on light transmittance. By localizing the ribs only to the extent necessary for alignment regulation (at the edges) rather than across the entire pixel area, the patent achieves effective alignment control while minimizing the total area blocked from light transmission.
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 strategic placement of ribs effectively shifts dark lines away from the display area, enhancing the transmittance and overall display quality of VA-mode liquid crystal display devices by improving the alignment of liquid crystal molecules and reducing light obstruction.
Implementation Method 1
a vertical alignment type liquid crystal layer; a first substrate and a second substrate facing each other with the liquid crystal layer interposed therebetween
Implementation Method 2
a first alignment film provided between the first electrode and the liquid crystal layer and a second alignment film provided between the second electrode and the liquid crystal layer
Implementation Method 3
the second substrate includes a first rib provided in an area corresponding to the first edge portion
Data Source
AI summary
VA-mode liquid crystal display device having a high display quality is provided. A liquid crystal display device according to the present invention includes a vertical alignment type liquid crystal layer; a first substrate and a second substrate facing each other with the liquid crystal layer interposed therebetween; a first electrode provided in the first substrate on the liquid crystal layer side and a second electrode provided in the second substrate on the liquid crystal layer side; and a first alignment film provided between the first electrode and the liquid crystal layer and a second alignment film provided between the second electrode and the liquid crystal layer. The liquid crystal display device includes a plurality of pixel areas located in a matrix. Each of the plurality of pixel areas includes a first liquid crystal domain in which a tilt direction of liquid crystal molecules at the center and in the vicinity thereof in a layer plane and in a thickness direction of the liquid crystal layer when a voltage is applied between the first electrode and the second electrode is a predetermined first direction, a second liquid crystal domain in which such a tilt direction is a predetermined second direction, a third liquid crystal domain in which such a tilt direction is a predetermined third direction and a fourth liquid crystal domain in which such a tilt direction is a predetermined fourth direction; and a difference between any two among the first direction, the second direction, the third direction and the fourth direction is approximately equal to an integral multiple of 90°.