Liquid Crystal Display Subpixel Storage Capacitor Kickback Voltage
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Solution Overview
Problem
Liquid crystal displays (LCDs) in the vertical alignment (VA) mode suffer from lower side visibility due to kickback voltage differences between subpixels, which deteriorate display quality.
Innovation Solution
The implementation of an additional storage capacitor formed by the expansion of the drain electrode of the second thin film transistor overlapping the storage electrode, increasing the total storage capacitance and eliminating kickback voltage differences between subpixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If one pixel is divided into two subpixels with different voltages applied to improve side visibility, then side visibility is improved, but kickback voltage difference between subpixels is generated causing visibility deterioration
Solution Approach 1:
The patent changes the voltage parameters by applying different voltages to the first and second subpixels (first voltage to first subpixel, second voltage to second subpixel) to optimize side visibility while managing kickback voltage differences through controlled voltage differentiation
Solution Approach 2:
The patent segments the pixel into two subpixels (first subpixel and second subpixel) with independent voltage control, allowing different voltages to be applied to each subpixel to improve side visibility while managing overall display quality
2Adaptability or versatility
If additional switching element is added to divide voltage between subpixels to improve side visibility, then voltage control flexibility is improved, but device complexity increases and kickback voltage difference is generated
Solution Approach 1:
The patent achieves voltage control flexibility by changing voltage parameters directly without additional switching elements, applying first voltage to first subpixel and second voltage to second subpixel through existing transistor structures
Solution Approach 2:
The existing thin film transistors serve dual purposes: they function as normal switching elements while also enabling voltage differentiation between subpixels through their drain electrode connections, eliminating the need for additional dedicated voltage control elements
3Reliability
If storage capacitance is increased to eliminate kickback voltage difference, then visibility consistency is improved, but device area increases
Solution Approach 1:
The patent merges the storage capacitor with the existing transistor structure by forming the capacitor between the drain electrode of the second transistor and the common electrode, combining two functional elements into a single integrated structure that increases storage capacitance without adding separate components
Solution Approach 2:
The drain electrode of the second transistor serves dual functions: as the output electrode of the transistor and as one plate of the storage capacitor, making the transistor element universal and eliminating the need for dedicated capacitor electrodes
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 solution enhances the display quality by preventing kickback voltage differences, thereby improving side visibility and maintaining consistent image quality across the display panel.
Implementation Method 1
The LCD displays images by applying voltages to the field-generating electrodes to generate an electric field in the LC layer that determines the orientation of LC molecules therein to adjust polarization of incident light
Implementation Method 2
a liquid crystal layer interposed therebetween... a liquid crystal layer which is interposed between the first substrate and the second substrate, and the liquid crystal layer comprises liquid crystal molecules
Implementation Method 3
the drain electrode of the second thin film transistor comprises an expansion, and the expansion overlaps a portion of the storage electrode thereby forming a storage capacitor
Data Source
AI summary
A liquid crystal display according to exemplary embodiments of the present invention is provided in which an additional storage capacitor is formed to a subpixel electrode connected to the dividing switching element, thereby increasing the total storage capacitance. Due to the additional storage capacitor, the kickback voltage difference between two subpixels that may be generated by the additional dividing switching element is eliminated such that the display quality deterioration has been improved by preventing the kickback voltage difference between the two subpixels.