LCD Pixel Structure Shielding Electrode Aperture Ratio
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Solution Overview
Problem
Existing LCD pixel designs face a trade-off between reducing parasitic capacitance-induced cross-talk and maintaining a high aperture ratio, as closer pixel and data line proximity increases capacitance but also generates cross-talk, while increasing storage capacitance area to improve brightness reduces the aperture ratio.
Innovation Solution
A pixel structure featuring a shielding electrode made of opaque conductive material, a plane organic layer with a dielectric constant of 0.5-3.7 positioned over the data line without overlapping with the shielding electrode, and a transparent conductive pixel electrode with a comb-like shape to minimize parasitic capacitance and maximize aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the pixel electrode and data line are placed closer to increase aperture ratio, then the aperture ratio is improved, but parasitic capacitance increases causing cross-talk
Solution Approach 1:
A shielding electrode is introduced as an intermediary component between the pixel electrode and the data line. This shielding electrode acts as a mediator that blocks the electromagnetic coupling between the pixel electrode and data line, thereby reducing parasitic capacitance and cross-talk while allowing the pixel electrode to be positioned closer to the data line to maintain high aperture ratio
2Object-affected harmful factors
If a shielding electrode is added to reduce cross-talk, then cross-talk is reduced, but the aperture ratio decreases due to the opaque material
Solution Approach 1:
The shielding electrode is designed with local quality by making it transparent in the region where it would otherwise block light. The transparent conductive oxide material provides the necessary shielding function against cross-talk while maintaining optical transparency, thus preventing aperture ratio degradation
Solution Approach 2:
The shielding electrode is constructed using composite materials, specifically a transparent conductive oxide (such as ITO, IZO, or IFO) that combines the electrical conductivity needed for shielding with optical transparency. This composite material property allows the shielding function to be achieved without sacrificing aperture ratio
3Reliability
If the pixel electrode is designed with comb-like structure to improve liquid crystal orientation, then liquid crystal alignment is improved, but storage capacitance area is reduced
Solution Approach 1:
The pixel electrode is segmented into a comb-like structure with multiple fingers, which improves liquid crystal orientation by providing multiple alignment directions. The segmentation allows the electrode to maintain effective capacitance area through the interdigitated fingers while achieving superior liquid crystal alignment 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 solution effectively reduces parasitic capacitance, minimizes cross-talk, and enhances the aperture ratio by optimizing the placement and materials of the pixel and data line components, allowing for improved display brightness and reduced power consumption.
Implementation Method 1
a plane organic layer positioned over the data line without overlapping with the shielding electrode... having a dielectric constant of 0.5-3.7
Implementation Method 2
a shielding electrode made of opaque conductive material... to reduce the effect of the parasitic capacitance
Implementation Method 3
the overlapped area 560 of the shielding electrode 540 with the peripheral portion of the pixel electrode 510 is configured to generate a storage capacitance therebetween
Data Source
AI summary
This invention in one aspect relates to a pixel structure. In one embodiment, the pixel structure includes a scan line formed on a substrate and a data line formed over the substrate defining a pixel area, a switch formed inside the pixel area on the substrate, a shielding electrode formed over the switch, a plane organic layer formed over the date line and the pixel area and having no overlapping with the shielding electrode, and a pixel electrode having a first portion and a second portion extending from the first portion, and formed over the shielding electrode and the plane organic layer in the pixel area, wherein the first portion is overlapped with the shielding electrode so as to define a storage capacitor therebetween, and the second portion overlays the plane organic layer and has no overlapping with the data line.