Common Electrode Shielding for LCD Cross Talk Reduction
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Solution Overview
Problem
In liquid crystal display (LCD) panels, particularly in fringe field switching (FFS) panels, parasitic capacitance between the data line and the pixel electrode causes signal interference, leading to unstable electric potential and poor display quality due to cross talk phenomena.
Innovation Solution
A common electrode is disposed between the data line and the pixel electrode as an electrical shielding layer, with slits to expose a portion of the pixel electrode and extend between them, reducing cross talk and improving display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the data line and drain electrode are fabricated on the same level as the pixel electrode, then the manufacturing process is simplified, but parasitic capacitance between the data line and pixel electrode causes cross talk and unstable electric potential
Solution Approach 1:
The common electrode is introduced as an intermediary shielding layer positioned between the data line and the pixel electrode. This mediator blocks the electromagnetic field interaction between the data line and pixel electrode, eliminating parasitic capacitance and cross talk while maintaining the simplified same-level fabrication process
2Reliability
If a shielding layer is added between the data line and pixel electrode, then cross talk is reduced, but the device structure becomes more complex
Solution Approach 1:
The common electrode serves multiple functions simultaneously: it acts as an electrical shielding layer to reduce cross talk, maintains the liquid crystal alignment, and participates in the liquid crystal driving operation. By combining these functions into a single component, the structure remains simple while achieving effective cross talk reduction
3Reliability
If the common electrode covers the entire data line, then shielding effect is maximized, but the liquid crystal driving capability is reduced
Solution Approach 1:
The common electrode is segmented with slits that expose portions of the pixel electrode. This segmentation allows different regions of the common electrode to perform different functions: the covered regions provide shielding against the data line, while the slit regions allow electric field penetration for liquid crystal driving, thus resolving the contradiction between shielding effectiveness and driving capability
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 implementation of the common electrode as a shielding layer effectively reduces cross talk between the data line and the pixel electrode, enhancing the stability of the electric potential and resulting in improved display quality without additional manufacturing processes or costs.
Implementation Method 1
a portion of a common electrode is disposed between a data line and a pixel electrode to be used as an electrical shielding layer
Data Source
AI summary
A pixel structure includes a scan line, a first insulation layer, a data line, a pixel electrode, a second insulation layer, and a common electrode. The scan line and the first insulation layer are disposed on a first substrate and the first insulation layer covers the scan line. The data line and the pixel electrode are disposed on the first insulation layer. The second insulation layer covers the data line and the pixel electrode and has a first opening located between the data line and the pixel electrode. The common electrode is disposed on the second insulation layer and has slits exposing a portion of the pixel electrode. The common electrode covers the data line and has a first extending portion filled in the first opening such that the first extending portion of the common electrode is located between the data line and the pixel electrode.