Mura Compensation Using Block Representative Values
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Solution Overview
Problem
Display devices suffer from mura effects due to differences in pixel characteristics, leading to varying luminance levels for the same gradation, which degrade display quality.
Innovation Solution
A test apparatus and method for mura compensation that calculates compensation coefficients and flags to adjust image signals based on detected luminance, dividing the display panel into blocks to determine representative values and prediction coefficients, minimizing mean squared error.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If compensation coefficients are calculated for all pixels individually, then mura compensation precision is improved, but memory capacity requirements increase
Solution Approach 1:
The patent divides the display panel into multiple blocks, and for each block, calculates a representative value (mean and standard deviation) that characterizes the pixel characteristics in that block. Instead of storing individual compensation coefficients for all pixels, the system stores block-level representative values and uses them to generate prediction compensation coefficients for individual pixels through mathematical relationships, thereby reducing memory requirements while maintaining compensation precision.
Solution Approach 2:
The patent transforms the compensation approach by changing from storing raw compensation coefficients for each pixel to storing statistical parameters (mean and standard deviation) for blocks of pixels. The actual compensation values are then derived through parameter transformation using mathematical formulas that relate pixel characteristics to compensation needs, reducing the quantity of stored data while preserving compensation accuracy.
2Quantity of substance
If block-wise prediction method is used to reduce memory usage, then memory capacity is reduced, but compensation precision may deteriorate
Solution Approach 1:
The patent incorporates a flag mechanism that provides feedback between the block-level prediction and individual pixel compensation. The flag is determined by comparing the prediction compensation coefficient with the actual sub compensation coefficient, and this flag information is stored and used to refine the compensation process. This feedback loop ensures that the block-wise prediction method maintains high precision by correcting prediction errors based on actual measurements.
3Measurement precision
If detailed pixel characteristics are stored for all pixels, then compensation accuracy is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the essential characteristics of pixel groups by calculating representative values (mean and standard deviation) for each block, rather than processing and storing detailed characteristics of every individual pixel. This extraction approach reduces data processing complexity while retaining the key information needed for accurate mura compensation through statistical representation.
Data Source
AI summary
A test apparatus includes: a compensation coefficient calculator configured to calculate a main compensation coefficient for a main gradation and a sub compensation coefficient for a sub gradation based on a detected image signal; a primary predictor configured to determine a representative value of each of a plurality of blocks of a display panel based on the detected image signal, and output a prediction compensation coefficient for the sub gradation based on the main compensation coefficient and the representative value corresponding to each of the plurality of blocks; a secondary predictor configured to determine a flag based on the sub compensation coefficient and the prediction compensation coefficient; and a controller configured to output the main compensation coefficient, the representative value, and the flag stored in a memory as compensation data.