Liquid Crystal Display Common Voltage Generator Flicker Reduction
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Solution Overview
Problem
Liquid crystal displays (LCDs) often suffer from poor side visibility and surface afterimages due to differences in optimum common voltages between white and black images, leading to flicker and image retention issues.
Innovation Solution
Applying an optimum common voltage measured at the highest grayscale level to the common electrode, which is averaged across multiple points on the display panel, minimizes flicker and surface afterimages by ensuring consistency in voltage across different grayscale levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If different optimum common voltages are applied for white and black images, then image quality is improved, but surface afterimage is generated
Solution Approach 1:
The patent applies the optimum common voltage measured at the highest grayscale level (white image condition) to the common electrode across all grayscale levels. This parameter change resolves the contradiction by using a single voltage value that prevents surface afterimage while maintaining acceptable image quality, eliminating the need for different voltages for white and black images.
2Object-generated harmful factors
If common voltage is optimized for white image, then surface afterimage is minimized, but black image quality may deteriorate
Solution Approach 1:
The patent converts the potential harm of using a single common voltage for all grayscale levels into a benefit by selecting the highest grayscale level's optimum voltage. This approach eliminates surface afterimage and the patent indicates that the difference in optimal voltages between grayscale levels is minimal (≤0.3V), so image quality remains acceptable across all levels.
3Manufacturing precision
If multiple common voltage measurements are taken at different positions, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent measures the optimum common voltage at five specific positions on the display panel and uses the average value. This partial measurement approach (measuring at key positions rather than all positions) achieves sufficient manufacturing precision while avoiding excessive measurement complexity.
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 approach reduces surface afterimages and improves side visibility by maintaining a residual direct current (DC) of zero at the highest grayscale level, enhancing the overall display performance.
Implementation Method 1
applying voltage to the field generating electrodes to generate an electric field on the liquid crystal layer, thereby determining alignment of liquid crystal molecules
Implementation Method 2
determining alignment of liquid crystal molecules of the liquid crystal layer through the generated electric field to control polarization of incident light
Implementation Method 3
determining alignment of liquid crystal molecules of the liquid crystal layer through the generated electric field to control polarization of incident light
Data Source
AI summary
A liquid crystal display includes: a display panel including a plurality of pixels arranged substantially in a matrix form, a plurality of gate lines connected to the pixels, and a plurality of data lines connected to the pixels; and a common voltage generator configured to generate a common voltage and apply the common voltage to the display panel, in which the common voltage generated from the common voltage generator is substantially the same as an optimum common voltage at a highest grayscale level, which minimizes flicker at the highest grayscale level.