Liquid Crystal Display Common Electrode Storage Capacitance
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Solution Overview
Problem
Liquid crystal display devices of the IPS mode face challenges in increasing storage capacitance between the pixel electrode and the common electrode, enhancing light transmission through the pixel region, and reducing parasitic capacitance between the pixel electrode and other conductive members, particularly due to the decreasing pixel region area.
Innovation Solution
The liquid crystal display device incorporates a transparent conductive pixel electrode and common electrodes with slits, where the second common electrode has slits extending along the data lines and the first common electrode overlaps the longitudinal edges of the slits, and a third insulating film with a lower dielectric constant is used to increase storage capacitance and light transmission while reducing parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pixel region area is decreased, then the display resolution is improved, but the storage capacitance between the pixel electrode and the common electrode becomes insufficient
Solution Approach 1:
The patent extends the common electrode in the depth dimension by creating a stepped structure where the common electrode has different heights in different regions. This allows the common electrode to overlap with the pixel electrode over a larger volume space without increasing the planar pixel region area, thereby maintaining high resolution while increasing storage capacitance.
Solution Approach 2:
The patent nests the common electrode within the pixel structure by positioning it in the inter-pixel region and using a stepped configuration where portions of the common electrode are embedded at different levels. This nested arrangement maximizes the overlapping area between the pixel electrode and common electrode within the constrained pixel region.
2Reliability
If the common electrode is disposed above and below the pixel electrode to increase storage capacitance, then the storage capacitance is improved, but the parasitic capacitance between the pixel electrode and other conductive members increases
Solution Approach 1:
The patent applies local quality by creating a stepped common electrode where different portions are positioned at different heights and locations. The common electrode has a first portion at a lower height and a second portion at a higher height, allowing selective overlap with the pixel electrode. This localized differentiation increases storage capacitance through controlled overlapping while minimizing parasitic capacitance by avoiding excessive proximity to other conductive members.
3Measurement precision
If the pixel region area is decreased, then the display resolution is improved, but the quantity of light passing through the pixel region decreases
Solution Approach 1:
The patent utilizes the depth dimension to increase the overlapping area between the pixel electrode and common electrode through a stepped configuration. This vertical stratification allows greater capacitance formation volume without reducing the planar aperture area, thereby maintaining high light transmission while achieving increased storage capacitance for high-resolution displays.
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 enhances display characteristics by increasing storage capacitance, improving light transmission through the pixel region, and reducing parasitic capacitance, leading to better image quality and reduced power consumption.
Implementation Method 1
a liquid crystal layer sandwiched between the first substrate and the second substrate
Implementation Method 2
a transverse electric field parallel to the substrates is generated between the pixel electrode and the common electrode
Implementation Method 3
a storage capacitance between the pixel electrode and the common electrode
Data Source
AI summary
A liquid crystal display device includes a plurality of pixel regions. Each of the pixel regions includes a thin-film transistor, a transparent conductive pixel electrode connected to the thin-film transistor, a first common electrode, a first insulating film disposed between the pixel electrode and the first common electrode, a second insulating film, a second common electrode that includes a plurality of slits, and a third insulating film. A space between two closely adjacent boundaries of a pair of pixel electrodes that are adjacent to each other in a longitudinal direction of the plurality of gate lines overlaps the first common electrode and the second common electrode in a plan view.