Image Sticking Controller for OLED Displays
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Solution Overview
Problem
Conventional organic light emitting displays suffer from image sticking due to degradation of organic light emitting diodes, leading to residual images on the screen, which affects display luminance and user experience.
Innovation Solution
An image sticking controller is introduced, comprising a gamma conversion unit, data accumulation unit, image sticking analysis unit, and data conversion unit, which accumulates and analyzes gray scale values across pixels, generates a control signal to adjust these values, and converts them to reduce image sticking by decreasing or increasing gray scale values based on accumulation data, thereby minimizing residual images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gray scale values are adjusted to compensate for pixel degradation, then image sticking is reduced, but display luminance uniformity may deteriorate
Solution Approach 1:
The patent applies local quality by selectively adjusting gray scale values for specific pixels based on their individual accumulation values. The data conversion unit identifies pixels with accumulation values exceeding reference values and applies compensation only to those pixels, rather than uniformly adjusting all pixels. This localized approach reduces image sticking in affected areas while preserving luminance uniformity in normal areas.
Solution Approach 2:
The patent changes the gray scale parameter dynamically based on accumulation data. The data conversion unit modifies gray scale values by adding or subtracting compensation values according to the difference between accumulation values and reference values. This parameter adjustment compensates for pixel degradation without causing excessive luminance shifts, as the compensation is calibrated to reference thresholds.
2Measurement precision
If accumulation data is stored for all pixels, then image sticking analysis precision is improved, but memory usage increases
Solution Approach 1:
The patent stores accumulation data in a structured format that associates each pixel's accumulation value with its specific location and characteristics. The memory unit organizes data by pixel coordinates and accumulation values, allowing precise tracking of individual pixel degradation while optimizing storage efficiency through selective data retention for pixels that require monitoring.
Solution Approach 2:
The patent segments the accumulation data into manageable units organized by pixel groups or regions. The data accumulation unit processes and stores data in a segmented manner, allowing efficient memory management and retrieval. This segmentation enables precise analysis of image sticking in specific regions without requiring excessive memory resources for the entire display.
3Reliability
If gray scale values are decreased to reduce image sticking, then residual images are minimized, but display brightness is reduced
Solution Approach 1:
The patent applies partial action by adjusting gray scale values only for pixels that exhibit degradation symptoms. The data conversion unit identifies specific pixels with accumulation values exceeding reference values and applies compensation only to those pixels, rather than reducing brightness across the entire display. This selective approach minimizes residual images in affected areas while preserving overall display brightness.
Solution Approach 2:
The patent dynamically changes gray scale parameters based on real-time accumulation data analysis. The data conversion unit adjusts compensation values according to the degree of pixel degradation, applying minimal necessary adjustments to maintain brightness while reducing image sticking. This adaptive parameter adjustment ensures that brightness is preserved as much as possible while still effective at preventing residual images.
Data Source
AI summary
An image sticking controller includes a gamma conversion unit configured to gamma-convert gray scale values respectively corresponding to a plurality of pixels, and to output the gamma-converted gray scale values as gamma conversion values, a data accumulation unit configured to accumulate the gamma conversion values into an accumulation data, the accumulation data including a minimum accumulation value, a maximum difference value indicating a difference between the minimum accumulation value and a maximum accumulation value, and difference values indicating respective differences between the minimum accumulation value and an accumulation value of each of the pixels, an image sticking analysis unit configured to output an image sticking decrease control signal when the maximum difference value is greater than a reference value, and a data conversion unit configured to convert the gray scale values in response to the image sticking decrease control signal, such that image sticking is reduced.