LCD Signal Controller Kickback Voltage Compensation
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Solution Overview
Problem
Liquid crystal displays (LCDs) face image quality degradation due to parasitic capacitance-induced kickback voltage, leading to asymmetrical effective voltages, afterimages, flicker, and crosstalk, which are not effectively addressed by existing technologies.
Innovation Solution
A liquid crystal display system that includes a signal controller capable of generating a target image signal by compensating for kickback voltage at each gray level, using a dithering unit to correct the image signal based on stored kickback voltage and dithering patterns, and alternately transmitting positive and negative corrected image signals to the liquid crystal panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If TFT switching device is used in LCD panel, then the LCD can be manufactured with standard semiconductor processes, but parasitic capacitance between gate electrode and drain electrode generates kickback voltage that distorts pixel electrode voltage
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing compensation values for kickback voltage at each gray level before actual display operation. The signal controller stores these compensation values in a lookup table and applies them in advance to counteract the kickback voltage distortion, thereby resolving the contradiction between using standard TFT manufacturing and eliminating voltage distortion.
2Manufacturing precision
If dithering is applied to compensate for kickback voltage, then display quality is improved, but the processing complexity of the signal controller increases
Solution Approach 1:
The patent applies parameter changes by modifying the image signal parameters through dithering processing. The signal controller adjusts the voltage values of pixel electrodes by applying dithering patterns and compensation values, thereby changing the electrical parameters to counteract kickback voltage effects and improve display quality while managing controller complexity.
Solution Approach 2:
The patent uses copying by creating multiple copies of compensation values and dithering patterns for different gray levels and pixel areas. The signal controller stores these copied patterns in lookup tables and applies them systematically, which simplifies the processing complexity while maintaining improved display quality through comprehensive kickback voltage compensation.
3Reliability
If kickback voltage compensation is applied to all gray levels, then afterimage and flicker are reduced, but the processing time and computational load increase
Solution Approach 1:
The patent applies preliminary action by pre-calculating compensation values for all gray levels and storing them in a lookup table before actual display operation. This allows the signal controller to quickly retrieve and apply the appropriate compensation value without real-time computation, thereby reducing processing time while maintaining image stability across all gray levels.
Solution Approach 2:
The patent applies local quality by tailoring the kickback voltage compensation to each specific gray level. The signal controller determines the current gray level of each pixel area and applies the corresponding pre-calculated compensation value, ensuring optimal compensation for each local gray level condition while avoiding unnecessary processing overhead.
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
The solution improves display quality by compensating for kickback voltage effects across all gray levels, reducing afterimages, flicker, and crosstalk, thereby enhancing the overall image quality and stability of the LCD.
Implementation Method 1
liquid crystals having dielectric anisotropy and injected between the first display substrate and the second display substrate
Implementation Method 2
parasitic capacitance created between a gate electrode and a drain electrode of the TFT may generate a kickback voltage
Data Source
AI summary
A liquid crystal display includes: a liquid crystal panel comprising a plurality of pixel areas, each having a plurality of pixels; and a signal controller configured to receive an original image signal and to generate a target image signal corresponding to the original image signal by using a kickback voltage at each gray level in the original image signal, wherein the signal controller comprises a dithering unit configured to generate a corrected image signal based on dithering patterns corresponding to the target image signal.