Compressed Texture Pixel Correction for Display Mura
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Solution Overview
Problem
Electronic displays face issues with uneven brightness or luminance due to manufacturing imperfections, known as 'mura,' which increase with smaller pixel sizes and higher resolutions, requiring significant memory and bandwidth for correction factors.
Innovation Solution
Generating and using a compressed texture for pixel correction, which reduces memory and bandwidth needs by quantizing and compressing adjustment values of adjacent sub-pixels, allowing for efficient storage and processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If correction factors for each pixel are stored in memory to correct mura defects, then luminance uniformity is improved, but memory size and bandwidth requirements increase significantly
Solution Approach 1:
The patent segments the correction data by dividing the display into multiple zones or regions, where each zone has its own correction factors stored in separate memory locations. This allows selective access to correction data for specific regions rather than loading all correction factors simultaneously, reducing peak memory bandwidth requirements while maintaining luminance uniformity across the entire display.
Solution Approach 2:
The patent implements a hierarchical memory structure where correction factors are organized in nested levels - with global correction factors stored in a smaller first memory and detailed per-pixel correction factors stored in a larger second memory. This nested arrangement allows the system to access only the necessary level of correction detail for each pixel, reducing overall memory size requirements while maintaining correction effectiveness.
2Illumination intensity
If correction factors for each pixel are stored in memory to correct mura defects, then luminance uniformity is improved, but bandwidth required to transfer correction factors increases
Solution Approach 1:
The patent performs preliminary computation of correction factors during manufacturing or initialization, storing pre-calculated correction values in memory. During operation, the display controller simply retrieves and applies these pre-computed factors rather than calculating them in real-time, significantly reducing processing bandwidth requirements while maintaining accurate luminance correction across all pixels.
Solution Approach 2:
The patent applies different correction strategies to different regions of the display based on local mura characteristics. High-bandwidth correction factors are stored only for regions with severe mura defects, while regions with minor defects use simpler correction factors or no correction at all. This localized approach reduces overall bandwidth requirements by transferring and storing correction data only where necessary.
Data Source
AI summary
Channel selection, quantization, and compression are used to reduce data size of textures used in pixel correction. For example, an apparatus such as a head-mounted display may include circuitry that retrieves a compressed texture from the memory, the compressed texture being generated using various compression techniques, and decompresses the compressed texture to determine adjustment quantization values for sub-pixels based on the compressed values. The circuitry determines reconstructed brightness adjustment levels for the sub-pixels based on the adjustment quantization values, and renders an image frame based on the reconstructed brightness adjustment levels. In some embodiments, the apparatus or a separate device generates the compressed texture in a calibration and stores the texture in a memory of the apparatus for use during the pixel correction.