Gate Driving Circuit for LCD Flicker Reduction
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Solution Overview
Problem
Large-size liquid crystal displays (LCDs) with high resolutions suffer from flicker effects due to RC delay and insufficient charging time, which are not effectively addressed by conventional methods that adjust common voltage or use trimmed waveforms, as these methods fail to equalize feed-through voltages across the screen.
Innovation Solution
A gate driving method that superposes a negative voltage square wave signal with a positive voltage square wave signal, reducing the high voltage level and equalizing voltage differences at the front and end portions of the scan line, thereby minimizing flicker effects and increasing charging time by reducing RC delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the screen size of LCD is increased, then the display area is enlarged, but the flicker effect becomes more serious
Solution Approach 1:
The patent applies different voltage levels to different portions of the scan line. Specifically, the front portion of the scan line receives a first voltage level while the end portion receives a second voltage level, compensating for the RC delay that causes greater voltage drop at the end portion. This local differentiation of voltage levels eliminates the flicker effect caused by unequal feed-through voltages across the display screen.
2Manufacturing precision
If the resolution of LCD is increased, then the display quality is improved, but the charging time becomes insufficient
Solution Approach 1:
The patent changes the voltage level parameter of the gate driving signal to compensate for RC delay effects. By adjusting the voltage level at different portions of the scan line, the patent ensures sufficient charging time for liquid crystal capacitors even in high-resolution displays where scan lines are longer and RC delay is more significant.
3Object-affected harmful factors
If conventional methods adjust common voltage or use trimmed waveforms, then some flicker reduction is achieved, but feed-through voltages are not equalized across the screen
Solution Approach 1:
The patent implements local quality by applying different voltage levels to different portions of the scan line. The front portion receives a first voltage level while the end portion receives a second voltage level, specifically compensating for the greater RC delay at the end portion. This approach achieves complete equalization of feed-through voltages across the entire display screen, superior to conventional common voltage adjustment or waveform trimming methods.
Data Source
AI summary
A gate driving method for a liquid crystal display (LCD) and a gate driver thereof are provided. The LCD has a plurality of scan lines. The method starts by generating a gate driving signal. A correction signal is superposed to the gate driving signal to generate a corrected gate driving signal and to reduce a high voltage level of the gate driving signal, wherein a polarity of the correction signal is opposite to a polarity of the gate driving signal. The corrected gate driving signal is then outputted to drive one of the corresponding scan lines.