Display Device Grayscale Correction for Afterimage Prevention
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Solution Overview
Problem
Display devices often exhibit unwanted afterimages due to hysteresis in driving transistors when displaying low grayscale images after high grayscale images, leading to conspicuous image artifacts.
Innovation Solution
A display device with a grayscale corrector that compares current and previous frame data to adjust low grayscale values to black, preventing afterimages by generating second data that changes low grayscale inputs to black grayscale when specific conditions are met, including high-low grayscale transitions and load or frequency thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If low grayscale values are displayed after high grayscale images, then the display device can show varied image content, but unwanted afterimages appear due to transistor hysteresis
Solution Approach 1:
The grayscale corrector performs preliminary detection and correction of low grayscale values before they are displayed. By comparing current frame data with previous frame data and identifying pixels that transition from high to low grayscale, the system proactively replaces these values with black (0 grayscale) to prevent afterimage formation before it occurs
Solution Approach 2:
The invention changes the grayscale parameter dynamically based on temporal context. When a pixel is detected to have transitioned from high grayscale in the previous frame to low grayscale in the current frame, its grayscale value is changed to black (0). This parameter transformation eliminates the hysteresis effect that causes afterimages while preserving the ability to display varied image content in frames where the condition is not met
2Object-affected harmful factors
If grayscale correction is applied to all pixels, then afterimages are prevented, but processing complexity and computational load increase
Solution Approach 1:
Instead of applying grayscale correction uniformly to all pixels, the invention applies correction only to specific pixels that meet the defined condition: pixels that had high grayscale values in the previous frame and low grayscale values in the current frame. This localized approach reduces computational complexity while maintaining effective afterimage prevention
Solution Approach 2:
The grayscale corrector performs partial correction by only modifying pixels that are likely to cause afterimages (those transitioning from high to low grayscale). This partial action is sufficient to prevent the harmful effect without the excessive processing that would result from correcting all pixels, thereby optimizing the balance between afterimage prevention and processing complexity
Data Source
AI summary
A display device includes a timing controller and a grayscale unit electrically connected to the timing controller. The timing controller may generate first data for a pixel for a previous frame and first data for the pixel for a current frame. The grayscale unit may output a black-corresponding grayscale as second data for the pixel when a predetermined condition is satisfied. The black-corresponding grayscale corresponds to black. The predetermined condition may include that the first data for the pixel for the previous frame is in a predetermined second gray scale range and that the first data for the pixel for the current frame is in a predetermined first grayscale range. The predetermined first grayscale range may be between the predetermined second grayscale range and the black-corresponding grayscale.