LCD Pixel Voltage Compensation for Cross-Talk Reduction
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Solution Overview
Problem
The cross-talk phenomenon in liquid crystal display (LCD) technology leads to image quality degradation due to voltage offsets on the common electrode, causing inaccuracies in displayed gray levels.
Innovation Solution
An LCD system adjusts pixel voltages to compensate for voltage offsets on the common electrode by calculating correction voltages based on the differences in original pixel voltages between adjacent pixel rows, ensuring that the voltage seen by liquid crystal molecules corresponds to the desired gray level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data lines are used to drive pixel rows, then the LCD can display images, but parasitic capacitors between data lines and common electrodes cause voltage offsets and cross-talk
Solution Approach 1:
The patent applies preliminary action by pre-calculating and compensating for the voltage offset caused by parasitic capacitors before the actual pixel driving occurs. The system calculates the average pixel voltage of a first pixel row, determines a voltage offset based on this average, and then compensates subsequent pixel voltages in a second pixel row by this offset amount before driving the pixels. This anticipatory compensation prevents the cross-talk phenomenon from degrading image quality.
2Ease of operation
If conventional driving methods are used, then the LCD operates simply, but gray levels are inaccurate due to common electrode voltage offsets
Solution Approach 1:
The patent implements feedback by using the average pixel voltage of a previously driven pixel row to determine the voltage offset for the next pixel row. The system continuously monitors and calculates the average voltage, uses it to compute the offset, and applies this offset as compensation to subsequent pixels. This closed-loop feedback mechanism ensures accurate gray level display while maintaining operational simplicity.
3Measurement precision
If voltage compensation is applied to all pixels, then gray level accuracy improves, but processing complexity increases
Solution Approach 1:
The patent applies local quality by differentiating the treatment of pixels based on their row position. Instead of applying uniform complex compensation to all pixels, the system calculates the average voltage of one row and uses this to compensate only the subsequent rows. This localized approach applies compensation where needed while avoiding unnecessary processing, thereby improving gray level accuracy without excessively increasing overall system 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 effectively reduces the cross-talk phenomenon, improving image quality by maintaining the correct common voltage level and ensuring accurate display of gray levels.
Implementation Method 1
a liquid crystal capacitor CLC
Implementation Method 2
the voltage seen by liquid crystal molecules corresponds to the desired gray level
Implementation Method 3
A parasitic capacitor is formed between the data line and the common electrode, wherein a parasitic capacitor Cxd is formed between the data line 240 and the common electrode 220
Data Source
AI summary
A liquid crystal display (LCD) includes an LCD panel, a scan driver, a timing controller and a data driver. The LCD panel includes first and second pixel rows. The timing controller determines a correction voltage index according to an absolute difference between an average of original pixel voltages corresponding to original pixel data of all pixels of the first pixel row, and an average of original pixel voltages corresponding to original pixel data of all pixels of the second pixel row, determines a correction voltage according to the correction voltage index, determines an adjusted pixel voltage in a target pixel according to an original pixel voltage of the target pixel in the second pixel row and the correction voltage, and outputs adjusted pixel data corresponding to the adjusted pixel voltage. The data driver outputs the adjusted pixel voltage to the target pixel according to the adjusted pixel data.