Gamma Correction Device Using Lookup Tables to Reduce OLED MTP Time
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Solution Overview
Problem
Manufacturing deviations in OLED display devices often result in products that do not meet target image quality standards, leading to inefficiencies and waste, as current multi-time programming (MTP) operations for correcting luminance and color coordinates significantly increase processing time.
Innovation Solution
A display device and gamma correction method that utilize a reference gray mapping table, gray mapper, dither, and data driver to map original gray levels to gamma correction gray levels, with upscaled bit representation and interpolation, allowing for efficient adjustment of luminances and color coordinates to achieve target gamma values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multi-time programming (MTP) operation is performed to correct luminance and color coordinates, then image quality reaches target level, but processing time is excessively increased
Solution Approach 1:
The patent pre-calculates and stores correction values in lookup tables during the module test phase. These pre-computed correction values are then directly applied during final product testing, eliminating the need for iterative MTP operations and significantly reducing processing time while maintaining image quality correction effectiveness.
Solution Approach 2:
The patent creates a simplified model of the correction process by storing correction data in lookup tables. Instead of performing complex iterative calculations on each final product, the system uses pre-generated correction lookup tables that replicate the correction effect, thereby drastically reducing computation time while preserving correction accuracy.
2Measurement precision
If measurements of luminances and color coordinates are repeatedly performed for MTP operation, then correction accuracy is improved, but takt time is excessively increased
Solution Approach 1:
The patent performs luminance and color coordinate measurements and generates correction data during the module test phase. The correction lookup tables are pre-generated with high measurement precision, allowing final products to apply corrections without repeated measurements, thus maintaining accuracy while improving productivity.
Solution Approach 2:
The patent copies the correction effect by storing pre-measured and pre-calculated correction values in lookup tables. This allows the system to achieve the same correction accuracy as repeated measurements would provide, but without the time cost of performing multiple measurement cycles on each final product.
3Manufacturing precision
If all end products determined as defective are discarded, then quality control is maintained, but waste increases and efficiency decreases
Solution Approach 1:
The patent extracts the correction capability from the manufacturing process by generating correction lookup tables during module testing. This allows defective end products to be separated from the defect category and corrected individually, converting what would be waste into usable products and reducing loss while maintaining quality control.
Solution Approach 2:
The patent changes the parameters of defective products by applying correction values from lookup tables to adjust luminance and color coordinates. This transforms products that would otherwise be discarded due to parameter deviations into acceptable products, reducing waste while maintaining quality standards.
Data Source
AI summary
A display device includes a display panel including a plurality of pixels, a reference gray mapping table configured to store reference gray mapping information indicating gamma correction reference gray levels to which reference gray levels are mapped, a gray mapper configured to map original gray levels indicated by input data to gamma correction gray levels using the reference gray mapping information stored in the reference gray mapping table, a dither configured to generate dithered output data to represent the gamma correction gray levels using the original gray levels, where a number of bits representing each of the gamma correction gray levels is greater than a number of bits representing each of the original gray levels, and a data driver configured to drive the display panel using the dithered output data.