Pixel Electrode Hollowed-Out Structure for ADS Mura Reduction
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Solution Overview
Problem
Existing Advanced Super-Dimensional Switch (ADS) display devices suffer from noticeable mura (nonuniformity in brightness or color) due to significant differences in parasitic capacitances between pixel electrodes and adjacent data lines, caused by conductive bridge lines and polarity inversions in the display driving process.
Innovation Solution
The display substrate design includes conductive bridge lines with hollowed-out structures on the pixel electrode ends, ensuring equal or balanced parasitic capacitances between the pixel electrode and nearest data lines, reducing the impact of polarity inversions and minimizing brightness differences between adjacent rows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conductive bridge lines are added to the pixel electrode, then the display response speed is improved, but the parasitic capacitance difference between pixel electrodes and adjacent data lines increases, causing mura
Solution Approach 1:
The patent applies local quality by creating hollowed-out structures at specific locations on the pixel electrode (first and second hollowed-out structures) to locally adjust the parasitic capacitance distribution. This allows the conductive bridge lines to maintain their speed-improving function while the hollowed-out regions compensate for the capacitance imbalance by reducing the effective area of the pixel electrode near the data lines, thereby equalizing the parasitic capacitance values.
2Reliability
If polarity inversion is used in the display driving process, then the liquid crystal fatigue is reduced, but the voltage changes caused by parasitic capacitance differences become more apparent, worsening the mura effect
Solution Approach 1:
The patent applies preliminary anti-action by pre-balancing the parasitic capacitances through the hollowed-out structures before the polarity inversion driving occurs. By equalizing the parasitic capacitance values in advance, the harmful voltage changes that would normally be amplified by polarity inversion are prevented, allowing the polarity inversion technique to maintain its fatigue-reduction benefit without causing mura.
3Object-generated harmful factors
If the pixel electrode area is reduced to balance parasitic capacitances, then the mura effect is minimized, but the aperture ratio and light transmittance decrease
Solution Approach 1:
The patent applies segmentation by dividing the pixel electrode into multiple regions, with hollowed-out structures created only in specific areas (first and second hollowed-out structures) where parasitic capacitance balancing is needed. This segmented approach allows the patent to reduce parasitic capacitance difference locally without significantly reducing the overall pixel electrode area, thereby maintaining both brightness uniformity and light transmittance.
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 design effectively reduces the voltage changes caused by polarity inversions, minimizing mura and achieving more uniform brightness across the display, thereby enhancing the display's image quality.
Implementation Method 1
an absolute value of a difference between parasitic capacitances formed respectively by the pixel electrode and nearest data lines located on both sides of the pixel electrode is less than or equal to a preset capacitance difference
Data Source
AI summary
A display substrate includes: a first base substrate (20), and gate lines (4) and data lines (5) on the first base substrate (20). The gate lines (4) extend in a first direction (X), and the data lines (5) extend in a second direction (Y). The gate lines (4) and the data lines (5) define pixel units, each of which includes a thin film transistor (7), a pixel electrode (8) and a common electrode (9). At least some of the pixel units are respectively configured with conductive bridge lines (10) provided in the same layer as the pixel electrode (8). In a pixel unit configured with the conductive bridge line (10), a first hollowed-out structure (13) and a second hollowed-out structure (14) are provided on opposite sides of the pixel electrode (8) in the first direction, to weaken or even eliminate mura (e.g., nonuniformity in brightness or color).