OLED Display Color Calibration Using Sparse Lookup Tables
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Solution Overview
Problem
The calibration of OLED display modules is complex due to non-linear channel-to-channel cross-talk, requiring a large number of measurements for accurate color reproduction, which increases manufacturing time and cost.
Innovation Solution
A method using dynamic optimization to select a reduced number of RGB input values for generating a sparse 3D lookup table, which is then up-sampled and inverted to create a calibration profile for accurate color calibration, reducing the need for extensive measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a large number of display characteristic measurements are taken for accurate color calibration of OLED display modules, then color calibration accuracy is improved, but manufacturing time and cost increase
Solution Approach 1:
The patent applies partial action by selecting only a subset of necessary color patches for measurement rather than measuring all possible patches. The system identifies and measures only the critical patches that provide sufficient calibration accuracy, reducing the total number of measurements required while maintaining acceptable calibration quality.
Solution Approach 2:
The patent changes the parameter of measurement quantity from a fixed large number to a dynamically optimized smaller number. By using optimization algorithms to determine the minimal sufficient set of measurements, the system transforms the calibration process from exhaustive measurement to efficient selective measurement, reducing manufacturing time while preserving accuracy.
2Manufacturing precision
If a large number of display characteristic measurements are taken for accurate color calibration of OLED display modules, then color calibration accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent reduces manufacturing cost by performing only the necessary partial set of measurements rather than exhaustive measurements. By identifying and measuring only the critical color patches that contribute most to calibration accuracy, the system minimizes the resources required for calibration while maintaining quality standards.
Solution Approach 2:
The patent optimizes the measurement parameter from a fixed high quantity to a dynamically determined optimal quantity. This parameter change enables cost reduction by eliminating redundant measurements while preserving the essential calibration information needed for accurate color reproduction.
3Device complexity
If traditional 3×3 matrix transformation is used for display module calibration, then the process is simple, but accuracy is limited due to non-linear channel-to-channel cross-talk in OLED displays
Solution Approach 1:
The patent changes the mathematical model from linear 3×3 matrix transformation to a more sophisticated model that accounts for non-linear channel cross-talk. By using lookup tables and optimization algorithms, the system captures the non-linear behavior of OLED displays, significantly improving calibration accuracy while managing complexity through computational methods.
Solution Approach 2:
The patent uses lookup tables that store pre-computed correction values based on extensive characterization data. Instead of relying on simple analytical transformations, the system creates a detailed digital copy of the display module's actual color behavior through measurement and storage, enabling accurate correction of non-linear effects without requiring complex real-time calculations.
Data Source
AI summary
This document describes techniques and apparatuses for performing color calibration of display modules using a reduced number of display characteristic measurements. In aspects, methods include generating a measured lookup table (50) for a source display module (32), using dynamic optimization to down-sample the measured lookup table and select a set of color patches, sending the color patches to a testing display module; measuring output values for the testing display module; generating a sparse lookup table (52) relating the color patches and the measured output values, up-sampling the sparse lookup table to a forward lookup table (54), and inverting the forward lookup table to generate a reverse lookup table (56). The reverse lookup table (56) can be utilized to determine correct output values (29) for driving a target display module to generate color lights within a display module color gamut.