OLED Driving Unit Dithering for Afterimage Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic light emitting diode (OLED) displays experience an afterimage phenomenon due to differing degrees of deterioration among pixels, especially when displaying still images for long periods, leading to inconsistent luminance and image quality issues.
Innovation Solution
A driving unit that includes a driving time accumulator, a ditherer, and a data signal generator, which determines the accumulated driving time of the display panel and adjusts the dithering operation by increasing the amount of dither, decreasing the number of gray levels, and modifying the unit block size as the accumulated driving time increases, thereby reducing the afterimage phenomenon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dithering operation is performed with fixed parameters, then image quality is maintained initially, but afterimage phenomenon occurs as accumulated driving time increases due to pixel deterioration
Solution Approach 1:
The patent applies dynamics by making dithering parameters adjustable based on accumulated driving time. The system dynamically modifies dithering strength, block size, and gray level distribution according to the current driving time, allowing the display device to adapt to pixel deterioration and prevent afterimage phenomenon while maintaining image quality consistency.
Solution Approach 2:
The patent implements parameter changes by modifying dithering operation parameters (dithering strength, block size, gray level distribution) based on accumulated driving time. As pixels deteriorate over time, the system adjusts these parameters to compensate for the deterioration, thereby preventing the afterimage phenomenon while maintaining reliable image quality.
2Object-affected harmful factors
If dithering operation is performed with increased amount of dither, then afterimage phenomenon is reduced, but device complexity increases due to additional control mechanisms
Solution Approach 1:
The patent applies preliminary action by pre-establishing the relationship between accumulated driving time and dithering parameters. The system proactively adjusts dithering parameters before significant afterimage phenomenon occurs, based on the current driving time, thereby preventing the harmful effect without requiring complex real-time detection and adjustment mechanisms.
Solution Approach 2:
The patent implements feedback by using the accumulated driving time as a basis for adjusting dithering parameters. The system continuously monitors driving time and uses this information to feedback-adjust the dithering operation, creating a closed-loop control mechanism that prevents afterimage phenomenon while maintaining manageable device complexity.
3Ease of operation
If dithering operation is performed on all regions uniformly, then simplicity of operation is maintained, but regions with different deterioration levels cannot be optimized
Solution Approach 1:
The patent applies local quality by dividing the display panel into multiple regions and applying different dithering parameters to each region based on its specific characteristics and accumulated driving time. This allows the system to optimize image quality for each region individually, accounting for local variations in pixel deterioration, while maintaining manageable operational complexity through systematic regional classification.
Data Source
AI summary
A driver for a display panel includes a driving time accumulator, a ditherer, and a data signal generator. The driving time accumulator determines an accumulated driving time of the display panel. The ditherer determines an amount of dither based at least in part on the accumulated driving time, and performs a dithering operation on input image data with the determined amount of dither. The data signal generator generates a data signal for the display panel based at least in part on the input image data on which the dithering operation is to be performed.