Display Panel Driving With Intermediate Voltage to Prevent Mura
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Solution Overview
Problem
Existing display technologies suffer from noticeable brightness and darkness variations (mura) due to different overdrive lookup tables being triggered during dynamic image transitions, leading to uneven display.
Innovation Solution
A display panel and method that dynamically adjusts driving voltages based on grayscale differences between frames, using a three-tiered voltage system: a first voltage for small differences, a second intermediate voltage for moderate differences, and a third voltage from the lookup table for large differences, with the second voltage acting as an intermediate to minimize brightness variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If overdrive lookup table is used to improve dynamic response speed, then liquid crystal molecules rotate rapidly to desired angle, but noticeable brightness and darkness variations (mura) occur at different positions during dynamic image transitions
Solution Approach 1:
The patent changes the voltage parameter dynamically based on grayscale difference thresholds. When grayscale difference is small, a first voltage is applied; when moderate, a second voltage is applied; when large, the overdrive lookup table provides a third voltage. This parameter change strategy maintains fast response where needed while preventing brightness variations in other regions.
Solution Approach 2:
The patent segments the grayscale difference range into three distinct intervals with different voltage strategies. By dividing the continuous grayscale difference spectrum into discrete segments (small, moderate, large differences), the system applies appropriate voltage levels to each segment, resolving the contradiction between response speed and brightness uniformity.
2Measurement precision
If different overdrive lookup tables are triggered at different positions during dynamic image transitions, then local grayscale accuracy is improved, but momentary watermarks and uneven display (mura) occur
Solution Approach 1:
The patent applies local quality by treating different grayscale difference regions with different voltage characteristics. Areas with small grayscale differences receive lower voltages to prevent overdrive artifacts, while areas with large differences receive higher voltages for fast response. This localized voltage adjustment maintains both grayscale accuracy and display uniformity.
Solution Approach 2:
The patent introduces an intermediary voltage (second voltage) for moderate grayscale differences that acts as a mediator between the first voltage (for small differences) and the third voltage from the lookup table (for large differences). This intermediary voltage smooths transitions and prevents the abrupt changes that cause momentary watermarks and mura.
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 reduces brightness discrepancies across the display, preventing momentary watermarks and uneven display (mura) by using calibrated intermediate voltages during dynamic transitions.
Implementation Method 1
due to the limited response speed of liquid crystals, it is difficult to achieve the desired deflection angle within one frame's time
Data Source
AI summary
A display panel and its driving method are provided. When a grayscale difference is less than a first preset grayscale threshold, a first driving voltage is determined to drive the display panel for displaying a current frame to be displayed. When the grayscale difference is greater than or equal to the first preset grayscale threshold and less than or equal to a second preset grayscale threshold, a second driving voltage is determined to drive display. When the grayscale difference is greater than the second preset grayscale threshold, an overdrive lookup table is invoked to determine a third driving voltage for driving display. The second driving voltage is greater than the first driving voltage and less than the third driving voltage. The second preset grayscale threshold is greater than the first grayscale threshold. This approach reduces brightness differences between different positions and prevents the occurrence of momentary watermarks or mura.