OLED Pixel Luminance Error Compensation via Subframe Adjustment
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Solution Overview
Problem
The digital driving method for OLED displays generates luminance errors and luminance reversal phenomena due to neglecting the on/off characteristics of pixels, leading to non-uniform compensation across different display panels.
Innovation Solution
A display device with a measurement unit to measure pixel currents, a luminance error calculation unit to calculate rush currents, and a luminance error compensation unit to adjust subframe emission times or gray levels, compensating for luminance errors by reducing emission times or switching between gray levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the digital driving method sets emission time of subframe periods linearly proportional to gray levels, then the device complexity is reduced and manufacturing is simplified, but luminance errors and luminance reversal phenomena occur due to neglecting pixel on/off characteristics
Solution Approach 1:
The patent applies parameter changes by modifying the emission time parameters of subframe periods based on measured luminance characteristics. Specifically, the emission times are adjusted from linear proportionality to nonlinear values that compensate for pixel on/off characteristics, thereby correcting luminance errors while maintaining the digital driving method's simplicity
Solution Approach 2:
The patent implements feedback by measuring the actual luminance output of pixels and using this information to adjust the emission time parameters. The measurement unit captures luminance data, which is then used to recalculate optimal emission times that compensate for observed luminance errors and reversal phenomena
2Ease of operation
If the digital driving method uses simple linear emission time allocation, then the ease of operation is improved, but luminance reversal phenomena occur between gray levels
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing corrected emission time parameters before actual display operation. The system performs initial measurements and calculations to determine optimal emission times that account for pixel characteristics, then applies these pre-determined parameters during normal operation to prevent luminance reversal phenomena
Solution Approach 2:
The patent modifies the emission time parameters from simple linear values to corrected nonlinear values that compensate for pixel on/off characteristics. This parameter change maintains ease of operation while eliminating luminance reversal phenomena between gray levels
3Ease of manufacture
If uniform compensation is applied to all display panels, then the ease of manufacture is improved, but luminance errors cannot be effectively compensated due to panel-specific characteristics
Solution Approach 1:
The patent applies local quality by implementing panel-specific compensation parameters tailored to each display panel's characteristics. Instead of uniform compensation, the system measures and calculates individualized emission time parameters for each panel, thereby achieving accurate luminance error compensation that accounts for manufacturing variations between panels
Solution Approach 2:
The patent uses feedback to achieve precise compensation by measuring the actual luminance output of each specific panel and using this information to calculate customized emission time parameters. This feedback mechanism enables accurate compensation tailored to each panel's unique characteristics rather than applying generic uniform compensation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively compensates for luminance errors and reversals, improving image quality by adaptively adjusting subframe times and gray levels based on measured pixel currents, ensuring uniform luminance representation across OLED displays.
Implementation Method 1
Each pixel may include a plurality of thin film transistors (TFTs), an organic light emitting diode (OLED), a capacitor, and the like.
Data Source
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AI summary
A display device and a self-calibration method thereof are disclosed. The display device includes a measurement unit measuring a current or luminance of a pixel, a luminance error calculation unit calculating a rush current of pixel at a measured current value of the pixel and calculating a luminance error of the pixel based on the rush current, and a luminance error compensation unit reducing an emission time of subframe period or changing a turned-on subframe period to compensate the luminance error of the pixel.