OLED Display Image Processing Circuit Reducing Ghost Effects
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Solution Overview
Problem
OLED display devices suffer from rapid deterioration and color distortion in fixed image regions due to uneven luminance correction, which accelerates OLED element degradation and shortens the display's lifespan.
Innovation Solution
An image processing method and circuit that differentially adjust the use rates of color components based on their luminous efficacies, applying a first conversion algorithm to fixed image regions to reduce the use of components with lower efficacy and increase the use of those with higher efficacy, thereby reducing deterioration and maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If luminance correction is applied to fixed image regions, then image quality is improved, but OLED element deterioration is accelerated
Solution Approach 1:
The patent applies different luminance correction strategies to different image regions. For fixed image regions, it uses a correction method that considers both luminance and luminous efficacy, while for non-fixed regions, standard correction is applied. This local differentiation prevents uniform acceleration of deterioration across the entire display.
Solution Approach 2:
The patent changes the correction parameters by introducing luminous efficacy as an additional factor alongside luminance. The correction value is calculated as a combination of luminance correction and luminous efficacy correction, which modifies the driving conditions to reduce stress on OLED elements while maintaining image quality.
2Measurement precision
If luminance correction is applied without considering luminous efficacy, then luminance uniformity is improved, but color distortion occurs
Solution Approach 1:
The patent applies different correction weights to different color components (R, G, B) based on their specific luminous efficacies. Each color channel receives a customized correction factor that accounts for its unique efficiency characteristics, preventing uniform but inaccurate correction that would cause color distortion.
Solution Approach 2:
The patent combines multiple correction factors (luminance correction factor and luminous efficacy correction factor) into a composite correction value. This composite approach integrates both brightness uniformity requirements and color accuracy requirements, achieving a balanced correction that satisfies both objectives simultaneously.
3Illumination intensity
If high gray scale data is displayed for long time, then image brightness is maintained, but screen burn-in occurs
Solution Approach 1:
The patent performs preliminary luminance correction before image display, calculating correction values based on expected luminance requirements and luminous efficacy. By pre-adjusting the driving data to account for OLED characteristics, it prevents excessive stress accumulation that would lead to burn-in during prolonged high-brightness display.
Solution Approach 2:
The patent implements a feedback mechanism where correction values are calculated based on the relationship between luminance, luminous efficacy, and OLED characteristics. This feedback loop continuously optimizes the driving data to maintain brightness while preventing deterioration, adapting to the OLED elements' actual performance state.
Data Source
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AI summary
Embodiments relate to reducing a ghost image effect caused by fixed images. In a region of the image with an opaque fixed image, a use rate (or intensity) of a color component with a lower luminous efficacy is decreased while a use rate (or intensity) of a color component with a higher luminous efficacy is increased to maintain the luminance. By reducing an excessive use of sub-pixels corresponding to a color component of the lower luminous efficacy, the deterioration of these sub-pixels can be reduced despite presenting a fixed image on the same region of the display.