OLED Pixel Degradation Compensation via Dynamic Sensing
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Solution Overview
Problem
Organic light emitting display devices face challenges in accurately compensating for pixel degradation due to changes in driving conditions, such as temperature, which affects the current-voltage characteristic curve and results in suboptimal luminance.
Innovation Solution
An organic light emitting display device with a sensing unit and timing controller that generates sensing signals based on reference signals, calculates a compensation coefficient representing the change ratio of the current-voltage characteristic of a pixel, and adjusts input data accordingly to compensate for degradation, including extrapolating sensing signals beyond the sensing capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reference voltage is provided to a pixel and degradation is compensated based on a pre-modeled current-voltage characteristic curve, then degradation compensation is achieved, but the compensation accuracy deteriorates when driving conditions (temperature, operation points) change
Solution Approach 1:
The patent implements dynamic compensation by continuously monitoring the actual current-voltage characteristics of the pixel under current driving conditions and adjusting the compensation values accordingly. Instead of relying on a static pre-modeled curve, the system dynamically adapts to temperature changes and operation point variations by measuring real-time pixel characteristics and updating compensation parameters to maintain accurate degradation compensation across varying conditions
Solution Approach 2:
The patent changes the compensation approach from using fixed pre-modeled parameters to using dynamically adjusted parameters based on actual measured current-voltage characteristics. The system varies compensation parameters according to measured pixel responses at different temperatures and operation points, allowing the compensation mechanism to adapt to changing driving conditions while maintaining measurement precision
2Measurement precision
If multiple sensing signals are measured at different reference signals to capture full current-voltage characteristic, then compensation accuracy is improved, but measurement time and complexity increase
Solution Approach 1:
The patent performs preliminary measurements of current-voltage characteristics at multiple reference signals during an initial characterization phase to establish a comprehensive model of pixel behavior. By capturing the full current-voltage characteristic curve in advance, the system creates a detailed reference model that enables accurate degradation compensation without requiring repeated extensive measurements during normal operation, thus reducing ongoing sensing time while maintaining measurement precision
Data Source
AI summary
An organic light emitting display device includes a display panel including a pixel disposed in an intersection of a data line, a feedback line, and a scan line, a data driver sequentially providing reference signals to the pixel though the data line, a sensing unit sequentially generating sensing signals based on voltages applied to the feedback line in response to the reference signals, and a timing controller calculating a compensation coefficient based on the sensing signals and compensating input data based on the compensation coefficient.