VA LCD Multi-Domain Alignment Film Opaque Shielding
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Solution Overview
Problem
Liquid crystal display devices with vertical alignment (VA mode LCDs) face challenges in achieving improved viewing angle characteristics due to misalignment issues and reduced luminance caused by the multi-domain structure, particularly when using slits or ribs for anchoring force, which leads to uneven response speed and decreased transmittance.
Innovation Solution
A VA mode liquid crystal display device is designed with a multi-domain structure where the pretilt directions are defined by an alignment film, and opaque portions are strategically placed to shield misaligned areas from incoming light, ensuring uniform viewing angles and improved display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If slits or ribs are used as alignment control structures to form multi-domain structure, then the anchoring force is applied to liquid crystal molecules, but the anchoring force becomes non-uniform within pixel region causing uneven response speed and decreased transmittance
Solution Approach 1:
The patent applies different alignment control methods to different regions of the pixel. Specifically, it uses alignment films with different pretilt directions in different areas to create the multi-domain structure, rather than using a uniform slit or rib structure throughout. This local differentiation ensures uniform anchoring force distribution while maintaining response speed consistency across the pixel region.
Solution Approach 2:
The patent replaces the mechanical slit or rib structures with alignment films that provide anchoring forces through molecular orientation. This substitution eliminates the physical obstructions (slits/ribs) that caused non-uniform anchoring and transmittance issues, while still achieving the desired multi-domain liquid crystal alignment through controlled pretilt directions in the alignment films.
2Reliability
If slits or ribs are provided for electrode to create anchoring force, then multi-domain structure is formed, but transmittance of light decreases in areas with slits or ribs causing luminance decrease
Solution Approach 1:
The patent replaces mechanical slits or ribs with alignment films that provide anchoring forces through molecular orientation. This substitution eliminates the physical obstructions that blocked light transmission, thereby maintaining high luminance while still achieving the desired multi-domain liquid crystal alignment through controlled pretilt directions in the alignment films.
Solution Approach 2:
The patent introduces alignment films as intermediary structures between the electrode and liquid crystal molecules. These alignment films provide the necessary anchoring forces through their molecular orientation without creating physical obstructions to light transmission, thus serving as a mediator that enables multi-domain formation while preserving luminance.
3Reliability
If alignment film is used to define pretilt directions for multi-domain structure, then misalignment occurs in VA mode LCD affecting display quality
Solution Approach 1:
The patent applies alignment films with specifically controlled different pretilt directions in different regions of the pixel to form the multi-domain structure. By carefully designing the pretilt angle distribution across different areas, the patent achieves precise alignment control that prevents misalignment issues while maintaining reliable multi-domain formation.
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 display quality of VA mode LCDs by minimizing the impact of misalignment, maintaining high luminance, and achieving better viewing angle dependence, thereby improving the overall performance of the liquid crystal display device.
Implementation Method 1
an alignment control structure is provided on one of the two substrates, which face each other with a vertical alignment liquid crystal layer interposed between them, so as to contact with the liquid crystal layer, thereby forming multiple domains with mutually different alignment directions
Implementation Method 2
Either the first substrate or the second substrate has an opaque member that includes at least one opaque portion for selectively shielding at least a portion of the dark area from incoming light
Implementation Method 3
a vertical alignment liquid crystal layer; a first substrate and a second substrate, which face each other with the liquid crystal layer interposed between them
Data Source
AI summary
A liquid crystal display device includes a vertical alignment liquid crystal layer, first and second substrates, first and second electrodes, and a pixel region which includes first, second, third and fourth liquid crystal domains in which liquid crystal molecules are tilted in first, second, third and fourth directions, respectively. The first liquid crystal domain is located close to at least a part of an edge of the first electrode, the second liquid crystal domain is located close to at least a part of another edge of the first electrode, the third liquid crystal domain is located close to at least a part of still another edge of the first electrode, and the fourth liquid crystal domain is located close to at least a part of yet another edge of the first electrode.