Pixel Structure Common Line Shielding for LCD Aperture Ratio
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Solution Overview
Problem
In LCD pixel structures, the capacitance between the data line and the pixel electrode leads to cross talk, which reduces the aperture ratio, and existing solutions using thicker insulator layers made of organic materials suffer from moisture absorption and reduced transmittance.
Innovation Solution
A pixel structure is designed with a common line between the pixel electrode and the data line, along with a connection layer to the drain, which reduces capacitance and increases aperture ratio, using a thin film transistor configuration with specific contact windows and conductive layers to enhance electrical connections and prevent line breaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the distance between the data line and the pixel electrode is shortened, then the aperture ratio is improved, but the capacitance between the data line and the pixel electrode is increased causing cross talk
Solution Approach 1:
A common line is introduced as an intermediary conductive layer positioned between the data line and the pixel electrode. This common line acts as a shield that reduces the direct capacitance coupling between the data line and pixel electrode, thereby reducing cross talk while allowing the data line to be positioned closer to the pixel electrode for improved aperture ratio
Solution Approach 2:
The conductive structure is segmented into multiple functional layers: the data line in the first patterned conductive layer, the common line in the second patterned conductive layer, and the pixel electrode. This segmentation allows each layer to perform its specific function - the common line specifically serves as a shielding layer to reduce capacitance coupling between other layers
2Object-generated harmful factors
If a thicker insulator layer is disposed between the pixel electrode and the data line, then the cross talk is reduced, but the adhesion is weakened due to moisture absorption and the overall transmittance is reduced
Solution Approach 1:
Instead of using a thick insulator layer as an intermediary, a conductive common line is used as the intermediary element. This common line is electrically connected to a reference potential and provides shielding against capacitance coupling without the moisture absorption and adhesion problems associated with thick organic insulator layers
Solution Approach 2:
The approach changes from increasing insulator thickness (geometric parameter) to introducing a shielded conductive structure (electrical parameter). By changing from an insulating mechanism to a shielding mechanism, the solution avoids the material reliability issues while achieving cross talk reduction
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 effectively reduces cross talk, increases the aperture ratio, and improves the reliability and orientation of liquid crystal molecules in LCD panels by shielding capacitance coupling and ensuring stable electrical connections.
Implementation Method 1
a capacitance (Cpd) between pixel electrode and a data line is one of factors affecting an aperture ratio
Implementation Method 2
the common line is located above the data line... effectively reduces cross talk... by shielding capacitance coupling
Data Source
AI summary
A method of manufacturing a pixel structure is provided. A first patterned conductive layer including a gate and a data line is formed on a substrate. A gate insulating layer is formed to cover the first patterned conductive layer and a semiconductor channel layer is formed on the gate insulating layer above the gate. A second patterned conductive layer including a scan line, a common line, a source and a drain is formed on the gate insulating layer and the semiconductor channel layer. The scan line is connected to the gate and the common line is located above the data line. The source and drain are located on the semiconductor channel layer, and the source is connected to the data line. A passivation layer is formed on the substrate to cover the second patterned conductive layer. A pixel electrode connected to the drain is formed on the passivation layer.