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 and 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 adjusts input drive levels, applicable to both optical and electrical measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If individual pixel measurements and offset determination are performed at multiple greyscale drive levels, then display uniformity is improved, but measurement time and processing complexity increase
Solution Approach 1:
The patent applies partial action by selecting a significant portion of greyscale drive levels rather than measuring all possible levels. This provides sufficient compensation data to achieve uniformity while reducing the total number of measurements required, thus balancing measurement time against display uniformity improvement.
Solution Approach 2:
The patent performs preliminary measurements at selected greyscale drive levels during manufacturing or calibration to determine offset values before actual display operation. This preliminary action creates a uniformity correction function that can be applied during normal operation without requiring continuous measurements, thereby reducing ongoing measurement time while maintaining uniformity.
2Measurement precision
If offset values are determined and stored for each pixel at multiple greyscale drive levels, then uniformity correction accuracy is improved, but memory requirements and data processing complexity increase
Solution Approach 1:
The patent changes the parameter representation by determining offset values at multiple discrete greyscale drive levels and using these to construct a uniformity correction function. This approach provides accurate correction across the full greyscale range while managing data complexity through selective sampling rather than continuous data storage.
Solution Approach 2:
The patent creates a uniformity correction function that serves as a mathematical model or copy of the pixel non-uniformity characteristics. This function can be applied to correct input drive levels without requiring storage and processing of raw measurement data for every possible input condition, thereby reducing processing complexity while maintaining correction accuracy.
3Manufacturing precision
If iterative adjustment of offset values is performed to achieve uniform flat field, then compensation accuracy is improved, but processing time and computational resources increase
Solution Approach 1:
The patent employs feedback by iteratively adjusting offset values based on measured pixel luminance values and comparing the result to the desired uniform flat field target. The offset values are refined through repeated measurements and adjustments until the uniformity criterion is satisfied, ensuring high compensation accuracy.
Solution Approach 2:
The iterative offset adjustment process is performed during manufacturing or initial calibration as a preliminary action. Once the optimal offset values are determined through iteration, they are stored and applied during normal display operation without requiring further iterative processing, thus achieving high compensation accuracy while minimizing impact on operational processing speed.
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.