LCD Driving Method for Image Sticking Reduction
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Solution Overview
Problem
Conventional LCD driving methods struggle with image sticking due to unidirectional electrical field deviations in the liquid crystal layer, which are difficult to remove, leading to image distortion, especially in dynamic images.
Innovation Solution
The method involves adjusting source signals and common signal voltages to optimize the voltage differences between the pixel and counter electrodes, ensuring that the optimized common signal voltages conform to specific conditions to minimize image sticking, particularly by interlacing voltage levels in neighboring gray levels for dynamic image display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional source signals with fixed middle-voltage are applied to the LCD, then the voltage difference between pixel electrode and counter electrode can be controlled for gray level adjustment, but unidirectional electrical field deviations occur in the liquid crystal layer causing image sticking
Solution Approach 1:
The patent applies periodic action by alternating the common signal voltage between higher and lower than the predetermined voltage in interlaced gray levels. This periodic voltage alternation creates alternating electrical field directions that prevent unidirectional deviation accumulation in the liquid crystal layer, thereby eliminating image sticking while maintaining gray level control precision
Solution Approach 2:
The patent changes the voltage parameter of the common signal from a fixed predetermined voltage to variable voltages that are alternatively higher and lower than the predetermined voltage. This parameter change allows the electrical field direction to alternate, preventing unidirectional deviation and image sticking while preserving the ability to control gray levels through source signal adjustment
2Measurement precision
If the common signal voltage is adjusted to compensate for feed-through voltage, then the voltage received by pixel electrode can be optimized, but the middle-voltage of source signal deviates from common signal voltage causing unidirectional electrical field deviation
Solution Approach 1:
The patent applies periodic action by alternating the common signal voltage between higher and lower than the predetermined voltage in interlaced gray levels. This periodic voltage alternation creates alternating electrical field directions that prevent unidirectional deviation accumulation in the liquid crystal layer, thereby eliminating image sticking while maintaining gray level control precision
Solution Approach 2:
The patent applies preliminary action by pre-adjusting the common signal voltage to be alternatively higher and lower than the predetermined voltage before applying the source signal. This preliminary voltage adjustment ensures that the electrical field deviation is compensated in advance, preventing unidirectional deviation and maintaining electrical field stability
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 effectively reduces image sticking by managing electrical field deviations, improving both surface and line shape sticking issues, and can significantly eliminate or improve image sticking when implemented in LCDs.
Implementation Method 1
The panel comprises a liquid crystal layer 11 disposed between a pixel electrode A (not shown) formed on a first substrate and a counter electrode (not shown) formed on a second substrate... the arrangement of molecules in liquid crystal layer 11 is adjusted for controlling the gray levels of liquid crystal layer 11
Data Source
AI summary
A method for driving a normal black type liquid crystal display (LCD) includes driving the LCD by applying uncompensated source signals corresponding to gray levels; recording first optimized common signal voltages (Vcom-opt1) of common signals corresponding with the gray levels; adjusting the source signal to drive the LCD so second optimized common signal voltages (Vcom-opt2) of common signals corresponding with the gray levels conform to the following conditions: (1) when the gray level is lower than a predetermined gray level, the Vcom-opt2 exceeds a predetermined voltage of the common signal and the absolute difference between the Vcom-opt2 and the predetermined voltage is less than or equal to that between the Vcom-opt1 and the predetermined voltage; and (2) when the gray level exceeds the predetermined gray level, the absolute difference between the Vcom-opt2 and the predetermined voltage is less than or equal to that between the Vcom-opt1 and the predetermined voltage.