Display Driving IC Gamma Mapping and Mura Compensation
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Solution Overview
Problem
Liquid crystal display panels often suffer from 'mura' defects, which cause non-uniform luminance and contrast issues due to imperfections in manufacturing processes, leading to visible defects like 'blobs', 'bands', and 'streaks' that affect display quality.
Innovation Solution
A driving apparatus and method that includes a conversion circuit and a voltage generating circuit, which selects a gamma table, maps image data to a gamma code, and generates a compensation result using a common de-mura table to reduce mura effects, ensuring uniform display voltage generation across the panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a gamma table is selected and applied to image data, then the display quality and luminance uniformity are improved, but the complexity of the driving apparatus increases due to the need for multiple gamma tables and de-mura tables
Solution Approach 1:
The patent divides the compensation process into two independent parts: gamma table selection for luminance control and de-mura table application for uniformity correction. The de-mura table is further segmented into pixel-specific compensation values that can be independently applied. This segmentation allows the system to handle multiple gamma tables without proportionally increasing overall complexity, as the de-mura compensation remains a separate, manageable layer.
Solution Approach 2:
The patent pre-calculates and stores de-mura compensation values in a lookup table during manufacturing or calibration. This preliminary action eliminates the need for complex real-time calculations during display operation. The de-mura table is prepared in advance based on measured luminance characteristics, allowing the driving apparatus to simply retrieve and apply pre-computed compensation values rather than performing complex computations during operation.
2Adaptability or versatility
If multiple gamma tables are stored for different display conditions, then the adaptability to different display panels and conditions is improved, but the memory storage requirements increase
Solution Approach 1:
The patent segments the compensation data into two distinct tables: gamma tables for luminance control and a single de-mura table for uniformity correction. By separating these functions, the system can store multiple gamma tables for different display conditions while using a single de-mura table, reducing the total memory footprint compared to storing complete compensation tables for each condition.
Solution Approach 2:
The de-mura table is designed to be universal and gamma-independent, serving the same compensation function across all gamma table selections. This multi-functionality allows the system to use a single de-mura table for all display conditions, eliminating the need to store separate de-mura tables for each gamma setting and significantly reducing memory requirements.
3Ease of manufacture
If de-mura compensation is applied independently of gamma table selection, then the manufacturing process complexity is reduced, but the precision of luminance control may be compromised
Solution Approach 1:
The patent segments the compensation process into independent gamma table selection and de-mura compensation stages. This segmentation allows the de-mura table to be generated once and reused regardless of which gamma table is selected, simplifying the manufacturing process. The independence of these stages means that de-mura compensation does not need to be recalculated for each gamma table, reducing manufacturing complexity while maintaining precision through the separate optimization of each compensation layer.
Data Source
AI summary
An integrated circuit for driving a display panel is provided. The integrated circuit includes a gamma mapping circuit and a mura compensation circuit. The gamma mapping circuit is configured to receive a gray level of an image data, map the gray level to a gamma code according to at least one gamma table, and output the gamma code. The mura compensation circuit is configured to receive the gamma code, and compensate the gamma code according to at least one de-mura table to generate a compensation result after the gamma mapping circuit performs the step of mapping the gray level to the gamma code. The integrated circuit drives the display panel according to the compensation result. In addition, a method for driving a display panel is also provided.