Display Mura Correction via Backlight and Pixel Gray-Level Adjustment
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Solution Overview
Problem
Display panels with non-uniform chromaticity and luminance, known as Mura, are treated as secondary products, affecting profitability, as they do not interfere with usage but are aesthetically displeasing and reduce panel manufacturer profits.
Innovation Solution
A method for adjusting display backlight and pixel gray-level luminance values to achieve uniformity, where the difference in luminance among backlight illuminants is between 0% and 10% and among pixels is between 0% and 5%, using a controller to generate signals that adjust these values based on detected chromaticity and luminance, improving display performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If display panels are manufactured with standard processes, then production efficiency is maintained, but non-uniform chromaticity and luminance (Mura) occur reducing product quality
Solution Approach 1:
The patent applies preliminary action by measuring and recording the chromaticity and luminance characteristics of each backlight illuminant and pixel during the manufacturing process. These measurements are stored in a lookup table (LUT) before the display is shipped, enabling pre-compensation for Mura effects through gray-level adjustment without requiring additional manufacturing steps.
Solution Approach 2:
The patent changes the gray-level parameters of backlight illuminants and pixels based on their measured characteristics. By adjusting the gray-level values according to the stored LUT data, the system compensates for manufacturing variations and achieves uniform chromaticity and luminance across the display panel.
2Manufacturing precision
If strict luminance uniformity is enforced during manufacturing, then display quality improves, but more panels are rejected as secondary products
Solution Approach 1:
Instead of rejecting panels with slight luminance variations, the patent adjusts the gray-level parameters of individual pixels and backlight illuminants based on their measured characteristics. This parameter adjustment approach allows panels that would traditionally be rejected as secondary products to be corrected and sold at full price.
Solution Approach 2:
The patent implements feedback by measuring the actual chromaticity and luminance of each pixel and backlight illuminant, storing these measurements in a LUT, and using this data to calculate compensatory gray-level adjustments. This closed-loop approach ensures that even panels with manufacturing variations meet quality standards.
3Manufacturing precision
If gray-level adjustment is applied to compensate for Mura, then chromaticity and luminance uniformity improve, but processing complexity increases
Solution Approach 1:
The patent reduces processing complexity by performing all measurements and calculations during manufacturing. The LUT is pre-populated with correction data, and the gray-level adjustments are automatically applied based on this pre-computed data, eliminating the need for complex real-time processing during display operation.
Solution Approach 2:
The patent creates a digital copy of the physical display characteristics by measuring and storing the chromaticity and luminance data of each pixel and backlight illuminant in a LUT. This digital model is then used to calculate and apply the appropriate gray-level corrections, simplifying the adjustment process.
Data Source
AI summary
An adjustment method, which is adapted in a display including a plurality of pixels and a plurality of backlight illuminants, includes: inputting an image signal with a single chromaticity and luminance to the display; adjusting a set of a backlight red gray-level luminance, a backlight green gray-level luminance, and a backlight blue gray-level luminance for each of the illuminants, and the difference of the luminance of the backlight illuminants is between 0 and 10%; and adjusting a set of a pixel red gray-level value, a pixel green gray-level value, and a pixel blue gray-level value for each of the pixels, and the difference of the luminance of the pixels is between 0% and 5%.