Display Panel Dual Scan Timing for Variable Refresh Color Stability
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Solution Overview
Problem
Display devices experience color deviation and luminance inconsistencies when driven at variable frequencies due to mismatched frame frequencies between the host processor and the display device, leading to tearing phenomena and uneven image quality.
Innovation Solution
The display device employs a dual scan operation, including an active scan and a dummy scan, with voltage level adjustments during overlap periods to maintain consistent luminance and reduce color deviation across different driving frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the display device is driven at variable frame frequency to prevent tearing phenomenon, then image synchronization is improved, but color deviation and luminance inconsistency occur
Solution Approach 1:
The patent applies preliminary action by performing a dummy scan operation before the actual active scan operation when frame data is not yet ready. This preliminary dummy scan initializes the pixel circuits and prepares them for the incoming frame data, ensuring that even at variable frame frequencies, the pixels are properly prepared and color consistency is maintained without tearing artifacts.
2Productivity
If active scan operation is performed at higher frequency to increase refresh rate, then productivity is improved, but color deviation increases due to incomplete dummy scan operation
Solution Approach 1:
The patent applies dynamics by making the scan operation adaptive to the frame frequency. When the frame frequency is high and the dummy scan cannot complete before the next frame arrives, the system dynamically adjusts by overlapping the dummy scan with the active scan operation, ensuring continuous operation while maintaining color uniformity through proper timing coordination.
Solution Approach 2:
The patent uses periodic action by structuring the scan operation into repeating cycles of dummy scan followed by active scan. This periodic structure ensures that pixel circuits are consistently initialized before each frame display, maintaining color uniformity across all frames regardless of the specific frame frequency being used.
3Manufacturing precision
If dummy scan operation is extended to ensure complete initialization, then color consistency is improved, but time consumption increases and frame rate decreases
Solution Approach 1:
The patent applies merging by combining the dummy scan operation with the active scan operation when the frame frequency is high. Instead of completing the entire dummy scan before starting the active scan, the system merges these operations by allowing them to overlap in time, thus reducing total scan time while maintaining color consistency through proper initialization.
Data Source
AI summary
A display device include: a display panel including first to third pixels, a data driver for providing first to third data voltages to the first to third pixels, and a scan driver for providing first and second scan signals to each of the first to third pixels. The scan driver performs a first active scan operation of sequentially providing the first and second scan signals to the first to third pixels in a first frame period, and perform a dummy scan operation of sequentially providing the second scan signal to the first to third pixels after the first active scan operation. The data driver changes a voltage level of at least one of the first to third data voltages in an overlap period in which the dummy scan operation and a second active scan operation of a second frame period are simultaneously performed.