Liquid Crystal Display Data-Line Driving Circuit Ghost Image Suppression
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Solution Overview
Problem
Ghost images are generated in liquid crystal display devices due to deviations in the average potential of positive-polarity and negative-polarity signals applied to data lines from the common potential, even when shifted by a predetermined value, leading to suboptimal image quality.
Innovation Solution
A liquid crystal display device with a data-line driving circuit that dynamically adjusts the average potential of positive-polarity and negative-polarity signals based on grayscale values, temperature, and distances from scanning-line and data-line driving circuits to minimize potential differences and prevent ghost image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the average potential of positive-polarity and negative-polarity signals is shifted from the common potential by a predetermined value, then ghost image generation is suppressed under certain conditions, but ghost images are still generated under other conditions (grayscale value, temperature, distance variations)
Solution Approach 1:
The patent applies dynamics by making the average potential shift value variable rather than fixed. The data-line driving circuit dynamically adjusts the average potential of positive-polarity and negative-polarity signals based on grayscale values, temperature conditions, and pixel circuit distances. This dynamic adjustment resolves the contradiction by adapting the potential shift to different operating conditions, preventing ghost images across various scenarios while maintaining reliability.
Solution Approach 2:
The patent changes the parameter of average potential shift from a predetermined fixed value to a variable parameter that depends on grayscale value, temperature, and distance. By modifying this key parameter adaptively, the system achieves both reliability (ghost image suppression) and adaptability (response to different operating conditions), resolving the technical contradiction between these two features.
2Reliability
If the average potential is kept equal to the common potential, then DC component issues are prevented, but ghost images are generated due to pixel electrode potential deviation
Solution Approach 1:
The patent applies local quality by implementing different potential strategies for different components. The common potential remains fixed to prevent DC component issues, while the data-line signal potentials (positive-polarity and negative-polarity) are locally adjusted with a dynamic average potential shift. This localized adjustment compensates for pixel electrode potential deviations without affecting the common potential, thereby preventing both DC component issues and ghost images.
Solution Approach 2:
The patent uses a counterbalancing approach by introducing an average potential shift that counteracts the potential deviation at the pixel electrode. This counter-potential adjustment compensates for the harmful effect of pixel electrode potential deviation, preventing ghost image generation while maintaining the common potential equality to prevent DC component issues.
3Device complexity
If a fixed average potential shift is applied, then the control is simple, but the solution is insufficient for varying temperature and distance conditions
Solution Approach 1:
The patent transitions from static to dynamic control by making the average potential shift value changeable based on operating conditions. The data-line driving circuit dynamically determines the appropriate shift value according to grayscale value, temperature, and pixel circuit distance, achieving reliable ghost image suppression without excessive complexity through adaptive control.
Solution Approach 2:
The patent implements feedback mechanisms where the system monitors operating conditions (grayscale value, temperature, distance) and adjusts the average potential shift accordingly. This feedback-based adjustment ensures reliable ghost image suppression across varying conditions while maintaining reasonable control complexity through systematic parameter adaptation.
Data Source
AI summary
A liquid crystal display device includes a plurality of pixel circuits, data lines, and a data-line driving circuit connected to the data lines. Each of the pixel circuits includes a pixel capacitance having one end provided with a common potential. In accordance with a grayscale value for one of the plurality of pixel circuits, the data-line driving circuit selectively outputs a positive-polarity signal and a negative-polarity signal to the one pixel circuit. The data-line driving circuit outputs the positive-polarity signal and the negative-polarity signal so that an average of a potential of the positive-polarity signal and a potential of the negative-polarity signal corresponding to the grayscale value changes in accordance with the grayscale value, a temperature, and a position of the one pixel circuit.