Entropy Coded Correction Data for Display Brightness Uniformity
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Solution Overview
Problem
Existing display technologies face challenges in efficiently correcting brightness irregularities across pixels in organic EL displays, requiring large memory capacities for storing correction data, which increases costs and complexity.
Innovation Solution
The use of entropy coding for correction data storage, specifically through Huffman coding, allows for reduced memory requirements by compressing data and storing it in a manner that enables efficient expansion and calculation of correction values for each pixel, thereby minimizing memory size while effectively correcting a wide range of irregularities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If correction data is stored for all pixels to correct brightness irregularities, then brightness uniformity is improved, but memory capacity and cost increase
Solution Approach 1:
The patent divides the display panel into multiple regions (e.g., blocks of 8x8 pixels or larger areas) and stores correction data at the region level rather than for each individual pixel. This segmentation approach reduces the total number of correction data entries from N pixels to N/M regions, significantly decreasing memory capacity requirements while maintaining acceptable brightness uniformity across the display
Solution Approach 2:
The patent transforms the correction data from per-pixel parameters to regional average parameters. By calculating and storing average correction values for each region instead of individual pixel values, the data dimension is reduced from O(N) to O(N/M) where M is the number of pixels per region, thereby reducing memory capacity while preserving correction effectiveness
2Adaptability or versatility
If bit width of correction memory is increased to correct wider range of irregularities, then correction capability is improved, but memory size increases
Solution Approach 1:
The patent implements variable bit-width correction data storage where the correction value precision is dynamically adjusted based on the actual irregularity magnitude of each region. For regions with small brightness variations, fewer bits are used; for regions with large variations, more bits are allocated. This dynamic adaptation allows wide correction range where needed while minimizing memory usage in regions requiring less correction
Solution Approach 2:
The patent applies different correction data precision levels to different display regions based on their specific characteristics. Regions with high brightness irregularity receive higher precision correction data (more bits), while regions with low irregularity use lower precision data (fewer bits). This localized quality approach optimizes the balance between correction capability and memory size for each specific region
Data Source
AI summary
After a look-up table applies γ correction to each of R, G, and B signals, a multiplier multiplies a γ corrected signal by a gain. An adder adds an offset to an output of the multiplier and supplies a resultant gain/offset corrected signal to a display panel. Memories store entropy coded correction data, which can be expanded by corresponding expansion circuits and supplied to the multiplier and the adder, respectively.