Display Scan Overlap Compensation 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 incorporates a data driver and scan driver that perform active and dummy scan operations, adjusting data voltage levels during overlap periods to synchronize with variable frame frequencies, and utilizes an overlap area detector and data compensator to compensate pixel data, reducing color deviation through compensation lookup tables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the display device operates at variable frame frequencies to prevent tearing, then adaptability to different host processor frame rates is improved, but color deviation and luminance inconsistency occur due to overlap periods between dummy scan and active scan operations
Solution Approach 1:
The patent changes the voltage level parameter of data signals during overlap periods to compensate for color deviation. Specifically, when a dummy scan operation of a first frame period overlaps with an active scan operation of a second frame period, the data driver adjusts voltage levels of data voltages to maintain consistent luminance and color across different driving frequencies, resolving the color deviation issue while preserving variable frame frequency adaptability
2Adaptability or versatility
If dummy scan operations are performed during overlap periods to synchronize with variable frame frequencies, then adaptability is improved, but additional scan operations increase the complexity of scan signaling
Solution Approach 1:
The scan driver is designed to perform multiple functions: it handles both active scan operations for normal display and dummy scan operations for frame synchronization. By integrating these functions into a single scan driver unit, the patent manages the complexity of variable frame frequency operation without requiring separate dedicated circuits for each function
3Manufacturing precision
If data voltage levels are adjusted during overlap periods to compensate for color deviation, then color consistency is improved, but additional control logic increases device complexity
Solution Approach 1:
The controller detects overlap periods between dummy scan and active scan operations and provides control signals to the data driver to adjust voltage levels accordingly. This feedback mechanism enables automatic compensation for color deviation during frequency transitions without requiring complex manual calibration or additional hardware components
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.