OLED Afterimage Reduction via Localized Brightness Control
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Solution Overview
Problem
Organic light emitting diode (OLED) panels in image display apparatuses suffer from burn-in, particularly when displaying static regions like logos or channel names, leading to reduced lifespan and difficulty in detecting translucent logos.
Innovation Solution
A signal processing device with a current calculator, accumulated current calculator, and afterimage reducer that calculates pixel and subpixel currents, generates a gain map, and adjusts brightness and contrast to reduce afterimages by lowering the brightness level of detection regions with high accumulated current, thereby extending the OLED panel's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If brightness is increased to improve image quality, then image quality is improved, but burn-in occurs more easily in OLED panels
Solution Approach 1:
The system performs preliminary detection of static regions (logos, text) before they cause burn-in damage. By identifying these regions in advance through image analysis and maintaining a history of displayed content, the system proactively adjusts brightness levels to prevent accumulation of degradation, thereby resolving the contradiction between displaying bright images and preventing burn-in
Solution Approach 2:
Instead of uniformly reducing brightness across the entire display, the system applies localized brightness adjustment only to detected static regions such as logos and text. This allows the rest of the image to maintain high brightness and quality while only the problematic static areas receive reduced brightness treatment, thus resolving the contradiction between overall image quality and preventing localized burn-in
2Reliability
If brightness is reduced to prevent burn-in, then OLED panel lifespan is extended, but image quality deteriorates
Solution Approach 1:
The system maintains high brightness for dynamic image content while applying brightness reduction only to static regions identified as prone to burn-in. This selective approach ensures that overall image quality is preserved for the majority of the display area, while only specific static elements receive brightness adjustment, thus resolving the contradiction between extending panel lifespan and maintaining image quality
3Measurement precision
If image processing is performed to detect static regions, then burn-in prevention accuracy is improved, but device complexity increases
Solution Approach 1:
The system performs preliminary analysis of the input image to identify static regions such as logos and text before displaying them. By detecting these regions in advance and comparing them with historical display data, the system achieves accurate burn-in prevention without requiring complex real-time processing during display, thus resolving the contradiction between detection accuracy and processing complexity
Solution Approach 2:
The system creates a simplified representation or map of the detected static regions rather than processing the entire high-resolution image continuously. This copying approach allows for accurate identification of burn-in prone areas while significantly reducing the computational complexity required for ongoing processing, thus resolving the contradiction between detection precision and device complexity
Data Source
AI summary
An image display apparatus is disclosed. The image display apparatus includes a current calculator configured to calculate pixel current of an input image, an accumulated current calculator configured to calculate accumulated current of the input image, and an afterimage reducer configured to output a second brightness level less than a brightness level of the input image with respect to a detection region if a level of the accumulated current is equal to or greater than a reference value. Thus, the lifespan of an image display apparatus including an organic light emitting diode panel is increased.