OLED Sensing Circuit Leakage Current Compensation
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Solution Overview
Problem
Organic light-emitting displays face reliability issues due to leakage currents in degradation information extraction, which reduces the accuracy of OLED degradation compensation methods.
Innovation Solution
The proposed solution involves an organic light-emitting display with a specific transistor configuration and sensing mechanism that applies a sensing voltage to suppress leakage currents, allowing for accurate degradation information measurement and compensation by using a controller to generate compensated image data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If degradation information is extracted from a pixel to compensate for OLED degradation, then the OLED luminance display accuracy is improved, but leakage current of the driving transistor is included in the degradation information reducing reliability
Solution Approach 1:
The patent extracts only the necessary component (OLED degradation information) from the total measured signal by separating it from the driving transistor leakage current through differential measurement techniques, thus obtaining pure degradation data without contamination
Solution Approach 2:
The patent introduces sensing transistors as intermediary elements that facilitate the measurement process by providing reference signals and enabling the separation of leakage current from actual degradation information through controlled comparisons
2Measurement precision
If a sensing voltage is applied to measure degradation information, then the measurement accuracy is improved, but leakage current is generated in the driving transistor
Solution Approach 1:
The patent converts the harmful leakage current into a useful reference signal by measuring it separately and using it to compensate for the total measurement, thus transforming the harmful effect into a beneficial correction factor
Solution Approach 2:
The patent changes the voltage parameters dynamically by applying different voltages to different transistors during the sensing process, including setting the first power supply voltage to match the sensing voltage level during specific time periods, to control and differentiate between leakage current and actual degradation signals
Data Source
AI summary
An organic light-emitting display comprises a first transistor comprising a gate electrode connected to a scan line, a first electrode connected to a data line, and a second electrode connected to a first node, a second transistor comprising a gate electrode connected to the first node, a first electrode connected to a first power supply voltage, and a second electrode connected to a third node, a third transistor comprising a gate electrode connected to a sensing control line, a first electrode connected to the data line, and a second electrode connected to the third node and an organic light-emitting device comprising an anode connected to the third node and a cathode connected to a second power supply voltage, wherein the first power supply voltage is set to a level of a sensing voltage for a period of time during which the sensing voltage is provided to the data line.