Image Data Processing Device for OLED Luminance Uniformity
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Solution Overview
Problem
Organic light emitting display devices experience display quality degradation due to uneven deterioration of transistors and organic light emitting diodes, leading to afterimages when the same image is continuously displayed, causing differences in luminance reduction between adjacent pixels.
Innovation Solution
An image data processing device that converts image data into modulation data by calculating the light emission amount for each pixel based on a ratio between different color data, adjusting the values to minimize luminance reduction differences across pixels, and applying these values to a transform matrix to generate modulation data for display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the same image is continuously displayed in a part of the display area, then the image can be maintained consistently, but different degrees of deterioration occur between the corresponding display area and adjacent display area, causing afterimage
Solution Approach 1:
The patent applies local quality by differentiating the treatment of pixels based on their color characteristics. Specifically, pixels displaying the fourth color (yellow, mixed from red and green) are identified and treated differently from other pixels. The image data processing device calculates fourth modulation data for yellow pixels based on a ratio between first data (red) and second data (green), while other pixels use standard modulation. This localized differentiation prevents uniform deterioration across all pixels, reducing afterimage effects while maintaining image consistency.
2Device complexity
If image data is converted into modulation data using standard methods, then the conversion process is simple, but the difference in luminance reduction between pixels increases, leading to afterimage
Solution Approach 1:
The patent implements parameter changes by modifying the modulation data calculation based on pixel color characteristics. For pixels displaying the fourth color (yellow), the device calculates fourth modulation data using a specific ratio between red and green color data, rather than applying uniform modulation to all pixels. This parameter adjustment equalizes the luminance reduction across different pixel types, preventing afterimage while adding minimal complexity to the processing pipeline.
3Reliability
If the fourth modulation data is calculated based on ratio between first data and second data, then the luminance reduction difference is minimized, but additional calculation steps are required
Solution Approach 1:
The patent applies segmentation by dividing pixels into different groups based on their color characteristics. Pixels are segmented into those displaying the fourth color (yellow, requiring ratio-based calculation) and other pixels (using standard modulation). This segmentation allows the complex ratio-based calculation to be applied only where necessary (to yellow pixels), rather than to all pixels, thereby minimizing luminance reduction differences while limiting the increase in calculation complexity to only the affected pixel population.
Data Source
AI summary
An image data processing device of the inventive concept includes an image data converter and a light emission amount calculator. The image data converter converts image data into modulation image data. The image data includes first to third data corresponding to the first to third colors, respectively. The modulation image data includes first to fourth modulation data corresponding to the first to fourth colors, respectively. The light emission amount calculator calculates the fourth modulation data based on the ratio between the first data and the second data. The fourth color includes a color based on mixing the first color and the second color.