Pixel Circuit Threshold Voltage Detection for OLED Uniformity
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Solution Overview
Problem
In OLED display devices, the threshold voltage of driving transistors can drift due to manufacturing variations and temperature changes, leading to uneven display and poor luminance uniformity, as existing methods cannot detect and compensate for these changes in real-time during the boot-up process.
Innovation Solution
A detection method for pixel circuits that applies data voltages in charge cycles to sense voltages, determining if they match reference voltages, and adjusts subsequent data voltages to equalize sensing voltages, allowing for real-time threshold voltage detection and compensation during boot-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If threshold voltage detection is performed only during shutdown state, then detection simplicity is maintained, but real-time compensation capability is lost
Solution Approach 1:
The patent applies preliminary action by performing threshold voltage detection during the boot-up process before the display enters normal operation. The detection is conducted in advance during charge cycles, allowing the system to prepare compensation data before actual display operations begin, thereby ensuring real-time compensation capability while maintaining detection effectiveness
2Speed
If sensing voltage is measured within a short duration after data voltage application, then detection speed is improved, but measurement accuracy may be compromised
Solution Approach 1:
The patent implements continuity of useful action by continuously monitoring the sensing voltage throughout the charge cycle rather than taking a single measurement. The system tracks voltage changes over time and uses the voltage value at the moment the driving transistor switches off, ensuring both rapid detection and accurate measurement by capturing the voltage at the optimal moment without requiring extended measurement duration
3Measurement precision
If multiple charge cycles are used for detection, then detection accuracy is improved, but processing time increases
Solution Approach 1:
The patent applies partial action by using only the necessary portion of charge cycles for detection purposes. Instead of requiring multiple complete charge cycles, the system performs detection during the boot-up charge cycles that are already occurring, extracting threshold voltage information from the voltage characteristics during these cycles without requiring additional redundant cycles, thus achieving accurate detection while maintaining boot-up efficiency
Data Source
AI summary
A detection method of a pixel circuit, a driving method of a display panel, and a display device are disclosed. The pixel circuit includes a driving transistor; and the detection method of the pixel circuit includes: in the first charge cycle, applying a first data voltage to a gate electrode of the driving transistor, acquiring a first sensing voltage at a first electrode of the driving transistor within the first duration after the application of the first data voltage and before the driving transistor is switched off, and determining whether the first sensing voltage is equal to reference sensing voltage.