Display panel compensation methods
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Solution Overview
Problem
Modern display technologies, particularly active matrix organic light emitting diode (AMOLED) panels, suffer from significant luminance non-uniformity due to factors like TFT threshold variation, OLED voltage and luminance variation, manufacturing tolerances, voltage drop, and contamination, leading to perceivable luminosity or color variations across images.
Innovation Solution
A method is developed to measure and compensate for pixel non-uniformity by selecting greyscale drive levels, determining offset values to create a uniform flat field, and using these measurements to generate a uniformity correction function that corrects input drive levels, applicable to both initial and post-usage corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If individual pixel measurements and compensation are implemented, then display uniformity is improved, but device complexity and processing requirements increase
Solution Approach 1:
The patent applies preliminary action by measuring and determining offset values for each pixel during the manufacturing process before the display is delivered to the user. These offset values are stored in a lookup table (LUT) and used to pre-compensate for pixel non-uniformity. This approach resolves the contradiction by addressing the uniformity issue upfront during manufacturing rather than requiring complex real-time compensation systems during operation.
Solution Approach 2:
The patent uses copying by creating a digital representation (lookup table) of the physical pixel characteristics measured during manufacturing. Instead of modifying the physical pixels themselves, the system creates a digital copy of the non-uniformity patterns and applies corrections through software-based offset values. This resolves the contradiction by using simple digital processing rather than complex hardware modifications.
2Measurement precision
If multiple greyscale drive levels are measured for each pixel, then compensation accuracy is improved, but measurement time and processing load increase
Solution Approach 1:
The patent applies partial action by selecting a limited number of representative greyscale drive levels (e.g., 2-5 levels) rather than measuring all possible greyscale values for each pixel. This subset of measurements is sufficient to capture the essential non-uniformity patterns and generate accurate offset values. This resolves the contradiction by achieving adequate compensation accuracy with reduced measurement time and processing requirements.
3Manufacturing precision
If offset values are determined for each pixel at multiple greyscale levels, then uniformity across different brightness levels is improved, but memory requirements and data storage increase
Solution Approach 1:
The patent applies parameter changes by storing offset values in a lookup table (LUT) that maps greyscale drive levels to compensation values. Instead of storing complete correction curves for each pixel, the system uses discrete offset values at selected greyscale levels. This resolves the contradiction by achieving uniformity across different brightness levels while keeping memory requirements manageable through efficient data representation.
Data Source
AI summary
What is disclosed are methods of non-uniformity compensation for active matrix light emitting diode device (AMOLED) and other emissive displays. For each pixel, greyscale level offsets for a number of predetermined greyscale drive levels which produce a uniform flat field are determined and used to generate a correction function for the pixel.