Display Device Light Stress Compensation via Multi-Size Pixel Blocks
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Solution Overview
Problem
Display devices face issues with light stress, which causes degradation of driving transistors, leading to non-uniform luminance across pixels, especially for n-type metal oxide semiconductor transistors, due to light emitted by adjacent pixels, resulting in shifted threshold voltages and color changes.
Innovation Solution
A display device with a controller that generates stress maps for different-sized pixel blocks, compensating image data to mitigate light stress effects by adjusting data voltages, ensuring uniform luminance and preventing color shifts through hue, saturation, and brightness value adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If driving transistors are implemented with n-type metal oxide semiconductor (NMOS) transistors to improve switching performance, then switching speed and efficiency are improved, but threshold voltage shifts intensify due to light stress
Solution Approach 1:
The controller performs preliminary light stress compensation by generating compensation values based on luminance data before driving the pixels. This advance preparation counteracts the threshold voltage shifts that would otherwise occur during operation, allowing NMOS transistors to maintain both high switching speed and stable threshold voltage.
2Illumination intensity
If pixels are driven at high luminance levels to improve display brightness, then display brightness is improved, but light stress on adjacent pixels increases causing non-uniform luminance
Solution Approach 1:
The controller applies local compensation by calculating light stress compensation values for individual pixels or pixel groups based on their specific positions and the luminance levels of adjacent pixels. This localized approach allows high brightness display while maintaining luminance uniformity across the entire display panel.
Solution Approach 2:
The system uses luminance detection data from the display panel to generate feedback compensation values. The controller continuously monitors actual luminance output and adjusts compensation values accordingly, creating a closed-loop system that maintains uniform luminance even at high brightness levels.
3Device complexity
If simple stress compensation is applied to reduce processing complexity, then device complexity is reduced, but compensation accuracy for pixels at different distances deteriorates
Solution Approach 1:
The controller segments the display panel into multiple regions or groups of pixels, applying different compensation strategies to each segment. This allows complex distance-based compensation to be broken down into simpler, manageable segments while maintaining overall compensation accuracy across the entire display.
Data Source
AI summary
A display device includes a display panel, a controller, and a data driver. The display panel includes a plurality of pixels. The controller is configured to: receive input image data for the display panel; divide the display panel into a plurality of first pixel blocks each having a first size; divide the display panel into a plurality of second pixel blocks each having a second size different from the first size; generate, based on the input image data, a first stress map for the plurality of first pixel blocks and a second stress map for the plurality of second pixel blocks; and generate output image data by compensating the input image data based on the first stress map and the second stress map. The data driver is configured to provide data voltages to the plurality of pixels based on the output image data.