Liquid Crystal Display Device with Patterned Common Electrode
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Solution Overview
Problem
The miniaturization of liquid crystal display devices is limited by the size of protrusions used in alignment control, leading to pixel miniaturization challenges and light leakage, which deteriorates contrast, especially near the side surfaces of protrusions.
Innovation Solution
A liquid crystal display device employing a Multi-domain Vertical Alignment (MVA) mode with a second common electrode having opening portions that control the inclination of liquid crystal molecules, reducing viewing angle dependency and preventing light leakage by ensuring vertical alignment in the OFF state and radial inclination in the ON state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If protrusions are used for alignment control in MVA mode, then liquid crystal molecules can be properly aligned to increase viewing angle, but the protrusions cannot be miniaturized due to manufacturing limits, which prevents pixel miniaturization
Solution Approach 1:
The invention extracts the alignment control function from the protrusion structure and relocates it to the common electrode pattern. By removing the protrusions and replacing them with a patterned common electrode having different potential regions, the alignment control is achieved without requiring physical protrusion structures, thereby enabling pixel miniaturization while maintaining multi-domain vertical alignment functionality.
2Adaptability or versatility
If protrusions are used for alignment control, then liquid crystal molecules align along the protrusion side surfaces, but this causes light leakage in the vicinity of protrusion side surfaces, which deteriorates contrast
Solution Approach 1:
The invention removes the protrusion structures that cause light leakage and transfers the alignment control function to the common electrode pattern. The patterned common electrode creates different potential regions that directly control liquid crystal molecule orientation without creating side surface inclination issues, thereby eliminating light leakage while maintaining effective alignment control.
Solution Approach 2:
The common electrode pattern acts as an intermediary between the voltage application and liquid crystal alignment control. Instead of relying on physical protrusions to induce alignment through side surface contact, the patterned common electrode uses electrical potential differences to control liquid crystal orientation, eliminating the harmful side surface inclination effect.
3Area of stationary object
If protrusions are miniaturized to enable pixel miniaturization, then pixel size can be reduced, but manufacturing precision cannot be maintained, making it difficult to properly form the alignment control structures
Solution Approach 1:
The invention extracts the alignment control function from difficult-to-miniaturize protrusion structures and implements it through a patterned common electrode. This approach eliminates the need for precise protrusion formation at small scales, as the common electrode pattern can be more easily miniaturized using standard thin-film fabrication techniques, thereby enabling pixel miniaturization while maintaining manufacturing feasibility.
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 configuration enhances display characteristics, prevents light leakage during black display, and allows for pixel miniaturization by reducing the size of the alignment control features, thereby improving contrast and viewing angles.
Implementation Method 1
rod-shaped liquid crystal molecules are substantially vertically aligned when no voltage is applied, and the liquid crystal molecules are substantially horizontally aligned when voltage is applied
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A liquid crystal display device includes: first and second substrates (11), (12); a liquid crystal layer (13) filled between the first and second substrates (11), (12); a pixel electrode (17) provided on the first substrate (11) in such a manner as to correspond to a pixel; a first common electrode (20) provided on the second substrate (12); a color filter (21) provided on the first common electrode (20); and a second common electrode (22) which is provided on the color filter (21), includes an opening portion (23) disposed in such a manner as to overlap the pixel electrode (17), and is electrically connected to the first common electrode (20).