LCD Pixel Structure with Insulation Interlayer for Parasitic Capacitance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal display devices using lateral electric fields face challenges in achieving uniform pixel voltage due to parasitic capacitance, leading to display defects like flicker and image persistence, especially when both picture and common electrodes are formed on the same substrate.
Innovation Solution
The design includes a first substrate with a first electrode and an insulation interlayer, a second electrode with slits facing the first electrode, and synchronized first and second transistors, ensuring equal parasitic capacitance between the electrodes to stabilize pixel voltage and prevent DC voltage components in the liquid crystal layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If both picture electrode and common electrode are formed on the same array substrate to achieve lateral electric field mode, then wide viewing angle and high quality display characteristic are obtained, but parasitic capacitance between gate and drain regions causes variation of pixel voltage leading to display defects such as flicker and image persistence
Solution Approach 1:
The pixel electrode is divided into two separate electrodes: a first electrode connected to the common line and a second electrode connected to the signal line. This segmentation allows independent control and balancing of parasitic capacitances, resolving the voltage stability issue while maintaining the lateral electric field mode benefits
Solution Approach 2:
The second electrode is designed with slits in specific regions to locally adjust capacitance distribution. The insulating interlayer is selectively positioned to balance parasitic capacitance between gate and drain regions, achieving uniform pixel voltage across different pixels
2Reliability
If insulation layer is provided between common electrode and pixel electrode to decrease parasitic capacitance, then image persistence is suppressed, but insulating layer apertures must be created which increases manufacturing complexity
Solution Approach 1:
The electrode structure is segmented into first and second electrodes with the insulating interlayer positioned between them. This segmentation allows the insulating interlayer to be formed using standard manufacturing processes without requiring complex aperture creation, while still achieving parasitic capacitance reduction
Solution Approach 2:
The insulating interlayer acts as an intermediary element between the first and second electrodes, providing electrical isolation and capacitance control. This intermediary structure simplifies manufacturing by using conventional layer formation techniques rather than requiring aperture creation in insulating layers
3Reliability
If pixel voltage variation is not equal in all pixels due to parasitic capacitance, then display defects such as flicker and image persistence occur, but designing around the variation is difficult when both electrodes are on the same substrate
Solution Approach 1:
The second electrode is designed with slits in specific local regions to adjust capacitance distribution across different pixels. The insulating interlayer is selectively positioned to balance parasitic capacitance locally, achieving uniform pixel voltage variation across all pixels while maintaining a relatively simple overall structure
Solution Approach 2:
The design adjusts physical parameters such as the position and dimensions of the insulating interlayer and the slit patterns in the second electrode to control parasitic capacitance values. By changing these parameters, uniform pixel voltage variation is achieved across all pixels, resolving the design complexity issue
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 stabilizes the signal voltage applied to the liquid crystal layer, eliminating flicker phenomena and preventing display persistence, thereby achieving high-quality display characteristics with uniform gradation.
Implementation Method 1
a liquid crystal display device driven by a lateral electric field and including picture and common electrodes formed on one substrate
Implementation Method 2
a liquid crystal layer is held between a pair of substrates, respectively having picture electrodes and a counter electrode, and a picture is displayed by selectively passing light from a backlight unit through a modulated liquid crystal
Implementation Method 3
an insulation interlayer formed on the first electrode, a second electrode arranged on the insulation interlayer
Data Source
AI summary
A liquid crystal display device includes first and second substrates and a liquid crystal layer interposed therebetween. The first substrate includes first and second electrodes separated by an insulation interlayer provided for each pixel. The second electrode has a plurality of slits. An alignment of liquid crystal molecules of the liquid crystal layer is controlled by operation of first and second transistors to control an electric field between the first and second electrodes. The first transistor includes a drain electrode coupled to the first electrode, and the second transistor includes a drain electrode coupled to the second electrode. The second transistor is switched in synchronization with the first transistor.