Luminance Correction System for OLED Mura Reduction
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Solution Overview
Problem
Flat panel display devices, such as OLEDs, suffer from luminance variations between pixels due to manufacturing characteristics, leading to luminance mura (unevenness) that degrade image quality and require lengthy optical compensation processes.
Innovation Solution
A luminance correction system using a CCD image capturing unit and a luminance correction device that calculates correction values by aligning image capturing elements with pixels, generating a representative luminance value, and applying a weighting matrix to correct luminance discrepancies, thereby reducing luminance mura and shortening optical compensation time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional optical compensation methods are used to correct luminance variations, then luminance mura can be reduced, but the compensation process time becomes excessively long
Solution Approach 1:
The patent divides the compensation process into two distinct stages: (1) a long-term compensation process that creates a lookup table (LUT) with correction values for different gray levels, and (2) a short-term real-time compensation process that applies pre-calculated correction values to individual pixels. This segmentation allows the time-consuming calculations to be performed once offline, while runtime compensation is rapidly executed using stored data.
Solution Approach 2:
The patent performs preliminary compensation calculations by pre-computing correction values for various gray levels and storing them in a lookup table before actual display operation. This preliminary action eliminates the need for complex real-time calculations during normal operation, significantly reducing the optical compensation process time while maintaining correction accuracy.
2Manufacturing precision
If pixel-level correction is applied to all pixels, then luminance mura can be corrected, but the measurement and correction process becomes excessively complex
Solution Approach 1:
The patent extracts and corrects only the dominant low-frequency luminance variations (luminance mura) rather than attempting to correct all pixel-level variations. By focusing on the most significant source of non-uniformity and using spatial filtering to separate low-frequency mura from high-frequency image details, the system achieves effective correction with simplified measurement and processing requirements.
Solution Approach 2:
The patent transforms the correction approach by changing from direct pixel-value adjustment to using a lookup table that maps input gray levels to corrected output values. This parameter transformation simplifies the correction process by pre-computing all necessary adjustments and storing them in an easily accessible table, reducing both measurement and correction complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively reduces luminance mura and shortens the optical compensation process time, ensuring image quality and aligning it with allocated takt time, thereby improving display uniformity and efficiency.
Implementation Method 1
an image capturing unit including a plurality of charge-coupled device (CCD) image capturing elements
Data Source
AI summary
Luminance correction systems and methods capable of reducing or removing luminance mura of display devices are provided. One luminance correction system includes: a display device including a plurality of pixels, the pixels including a plurality of sub-pixels, each of the pixels comprising at least two of the sub-pixels; an image capturing unit including a plurality of charge-coupled device (CCD) image capturing elements, an n×n arrangement of the image capturing elements corresponding torn of the pixels, n and m being natural numbers greater than or equal to 2; and a luminance correction device configured to generate a representative luminance value with respect to the m of the pixels based on luminance values measured by the n×n arrangement of the image capturing elements, and calculate a correction value with respect to the m of the pixels according to a difference between the representative luminance value and a target luminance value.