Shield Electrode Reduces Coupling Capacitance in LCD Array Substrates
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Solution Overview
Problem
Existing liquid crystal display (LCD) devices, such as IPS and FFS mode LCDs, face limitations in aperture ratio and light transmittance, which affect viewing angles and overall display performance.
Innovation Solution
An array substrate design featuring a gate line, data line, common electrodes, a shield electrode, and pixel electrodes, where the common electrodes are spaced apart and receive the same voltage, overlapping with the pixel electrodes to minimize coupling and enhance aperture ratio and light transmittance by creating an electric field that prevents coupling between the pixel electrode and data line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the pixel electrode is positioned close to the data line to enhance aperture ratio, then the aperture ratio is improved, but coupling capacitance between the pixel electrode and data line increases causing display defects
Solution Approach 1:
A shield electrode is introduced as an intermediary component positioned between the pixel electrode and the data line. This shield electrode acts as a mediator that blocks the electric field coupling between these two conductive elements, thereby reducing coupling capacitance while allowing the pixel electrode to maintain its close proximity to the data line for high aperture ratio
Solution Approach 2:
The harmful coupling effect is extracted and isolated by separating the electric field paths using the shield electrode. The shield electrode creates distinct electric field zones, extracting the unwanted capacitive coupling from the system while preserving the desired electric field for liquid crystal modulation
2Device complexity
If common electrodes are formed continuously to simplify structure, then device complexity is reduced, but light leakage increases reducing light transmittance
Solution Approach 1:
The common electrode is segmented into multiple discrete common electrodes that are spaced apart rather than forming a continuous structure. This segmentation allows the introduction of non-conductive spacing regions that block light leakage paths while maintaining the essential function of providing a common electric potential reference for the liquid crystal cells
Solution Approach 2:
Different regions of the electrode structure are assigned different properties: the common electrodes maintain conductive quality for electrical function, while the spacing regions between them provide insulating quality to block light leakage. This local differentiation of properties resolves the contradiction between structural simplicity and light control
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 design enhances the aperture ratio and light transmittance of the display panel, improving viewing angles and display performance by reducing coupling capacitance and blocking light leakage, thereby increasing the efficiency of liquid crystal molecule arrangement and light control.
Implementation Method 1
An electric field of a common electrode pattern may prevent coupling between a pixel electrode and a data line
Implementation Method 2
liquid crystal molecules rotate in a plane substantially parallel to an alignment layer of a substrate
Implementation Method 3
the difference in refractive index anisotropy is small when viewed by a viewer
Data Source
AI summary
An array substrate includes a gate line, a data line, a plurality of common electrodes, a shield electrode, and a pixel electrode. The gate line is extended along a first direction, and the data line is extended along a second direction. The common electrodes are formed in a plurality of pixel areas. The common electrodes are spaced apart from each other. The shield electrode is formed below the data line and formed between the common electrodes formed in the pixel areas adjacent to each other. The pixel electrode is overlapped with the common electrodes. The pixel electrode has a plurality of openings formed thereon. Therefore, an electric field of a common electrode pattern may prevent coupling between a pixel electrode and a data line, so that a distance between the pixel electrode and the data line may be minimized, and thus an aperture ratio and light transmittance may be enhanced.