Pixel Driving Method for LCD Color Washout Mitigation
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Solution Overview
Problem
Liquid crystal display (LCD) devices experience a color washout phenomenon when viewed from large angles due to differences in gamma curves between direct and side viewing angles, particularly affecting middle and high gray levels, as existing solutions only partially mitigate this issue by making one sub-pixel consistently brighter than the other.
Innovation Solution
A pixel driving method that adjusts the driving voltages of sub-pixels within a frame period to ensure the equivalent gray level is equal to or greater than a setting gray level, with one sub-pixel not consistently brighter than the other, using a spatial or temporal approach to maintain consistent luminance across all gray levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If one sub-pixel is constantly brighter than another sub-pixel, then the color washout phenomenon of low and high gray levels is mitigated, but the color washout phenomenon of middle and relatively high gray levels remains severe
Solution Approach 1:
The patent applies dynamics by making the brightness relationship between sub-pixels variable rather than fixed. The driving voltages of sub-pixels are dynamically adjusted based on the target gray level, transitioning from a constant brightness difference to a dynamic brightness relationship that adapts to different gray level requirements throughout the frame period.
Solution Approach 2:
The patent implements periodic action by alternating the brightness relationship between sub-pixels during different time segments of the frame period. The driving voltages are periodically switched to create different luminance combinations, ensuring that no single sub-pixel is constantly brighter, thereby addressing color washout across all gray levels through time-varying control.
2Manufacturing precision
If the equivalent gray level is equal to or greater than a setting gray level, then one sub-pixel should not be constantly brighter than another, but maintaining consistent luminance across all gray levels becomes challenging
Solution Approach 1:
The patent applies parameter changes by systematically varying the driving voltages of sub-pixels based on the target gray level. Different voltage parameters are applied to different sub-pixels depending on the desired gray level, enabling precise control over luminance combinations while avoiding constant brightness dominance of any single sub-pixel.
Solution Approach 2:
The patent implements feedback by using the target gray level as a reference to determine the appropriate driving voltage combination. The system monitors the required gray level and adjusts sub-pixel voltages accordingly, creating a closed-loop control mechanism that ensures accurate color reproduction across all gray levels while managing driving complexity.
Data Source
AI summary
A method for driving a pixel is provided. The method includes determining a first predetermined gray-level and a second predetermined gray-level which are corresponding to a target gray-level according to the target gray-level of the pixel, wherein an equivalent gray-level corresponding to the first predetermined gray-level and the second predetermined gray-level is equal to the target gray-level, thereafter, generating a first driving voltage and a second driving voltage according to the first predetermined gray-level and the second predetermined gray-level for respectively driving a first sub-pixel and a second sub-pixel within the pixel during a frame period. The first driving voltage is greater than the second driving voltage when the equivalent gray-level is small than a first setting gray-level; the first driving voltage is small than the second driving voltage when the equivalent gray-level is greater than the first setting gray-level.