Liquid Crystal Display Sub-Pixel Gamma Compensation
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Solution Overview
Problem
Liquid crystal display devices with two-color filters face issues of uneven brightness and color reproduction due to limited response speed and differences in gamma characteristics between sub-pixel drive signals during different sub-frames, leading to lower image quality.
Innovation Solution
A liquid crystal display device with a timing controller and a compensation unit that generates and compensates sub-pixel data streams for two sub-frames with different gamma characteristics, ensuring that sub-pixels are driven with varying compensation rates to reach the desired voltage state uniformly across the panel, thereby correcting gamma differences and enhancing color reproduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If sub-pixels are driven with the same drive signal for both sub-frames, then the device structure is simple, but gamma characteristics differ between sub-frames causing uneven brightness and poor color reproduction
Solution Approach 1:
The patent divides the drive signal into separate first and second sub-pixel drive signals for the first and second sub-frames respectively. This segmentation allows each sub-frame to have optimized gamma characteristics tailored to its specific color composition (red/blue for first sub-frame, green/cyan for second sub-frame), resolving the gamma uniformity issue while maintaining clear signal structure
Solution Approach 2:
The patent applies different gamma characteristics to different sub-frames based on their specific color requirements. The first sub-pixel drive signal is optimized for red/blue light penetration while the second is optimized for green/cyan light penetration, ensuring each region of the display has the appropriate characteristics for its function
2Stability of the object's composition
If the liquid crystal response time is extended to achieve uniform voltage state across the panel, then brightness uniformity improves, but the response speed decreases causing motion blur
Solution Approach 1:
The patent applies an overshoot compensation value to the sub-pixel drive signals in advance, before the liquid crystal response occurs. This preliminary adjustment anticipates the delayed response and pre-compensates for it, ensuring that when the liquid crystal finally responds, it reaches the correct voltage state uniformly across the panel without waiting for extended response time
Solution Approach 2:
The patent changes the drive signal parameters by adding an overshoot compensation value that varies based on the liquid crystal molecule's position and orientation. This parameter adjustment allows different regions of the liquid crystal to be driven with appropriately tailored signals that account for their specific response characteristics, achieving uniformity without extending overall response time
3Manufacturing precision
If different gamma characteristics are used for first and second sub-frames, then color reproduction accuracy improves, but data processing complexity increases
Solution Approach 1:
The patent segments the color reproduction process into two distinct sub-frame operations, each with its own optimized gamma characteristics. The first sub-frame handles red/blue colors with appropriate gamma settings while the second sub-frame handles green/cyan colors with different gamma settings, achieving accurate overall color reproduction through this division
Solution Approach 2:
The patent uses periodic alternation between first and second sub-frames, each with their respective optimized gamma characteristics. This periodic switching allows the system to leverage the benefits of different gamma settings for different color groups while maintaining a manageable processing rhythm through regular alternation
Data Source
AI summary
A liquid crystal display device includes a liquid crystal panel, a timing controller, a compensation unit and a panel drive circuit. The liquid crystal panel has a plurality of color pixels, each of the color pixels including two sub-pixels which represent two different colors. The timing controller generates a sub-pixel data stream of two sub-frame format. The sub-pixel data stream of two sub-frame format includes a first sub-pixel data for a first sub-frame and a second sub-pixel data for a second sub-frame. The first sub-pixel data and the second sub-pixel data have different gamma characteristics. The compensation unit is operable to compensate the first sub-pixel data and the second sub-pixel data with different rates. The panel drive circuit drives the sub-pixels on the liquid crystal panel and supplies the sub-pixels with the compensated first sub-pixel data for the first sub-frame and the compensated second sub-pixel data for the second sub-frame.