Pixel Driving Circuit Threshold Voltage Compensation
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Solution Overview
Problem
Active-matrix OLED display panels face issues with uneven brightness due to the drift of the threshold voltage of the driving transistor, which affects the consistency of the display.
Innovation Solution
A pixel driving circuit is designed with a specific configuration that includes multiple controlling circuits and energy storing circuits to control the voltage at the gate of the driving transistor, ensuring that the driving current is independent of the threshold voltage, thereby maintaining consistent brightness by compensating for the current threshold voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional 2T1C pixel driving circuit is used, then the device complexity is low, but the brightness uniformity deteriorates due to threshold voltage drift
Solution Approach 1:
The pixel driving circuit is segmented into multiple functional modules: a driving transistor for current control, a first controlling circuit for data signal input, a second controlling circuit for node connection control, a third controlling circuit for voltage signal input, energy storing circuits for voltage compensation, and adjusting circuits for threshold voltage compensation. Each module performs a specific function to collectively solve the brightness uniformity issue caused by threshold voltage drift.
2Illumination intensity
If the driving current is increased to improve brightness, then the illumination intensity improves, but the power consumption increases
Solution Approach 1:
The circuit dynamically adjusts the driving current by compensating for threshold voltage drift through the energy storing circuits and adjusting circuits. By maintaining the driving transistor at optimal operating parameters despite voltage drift, the circuit achieves consistent brightness without requiring excessive current increases, thus balancing illumination intensity and power consumption.
Data Source
AI summary
Embodiments of the present disclosure provide a pixel driving circuit, a driving method thereof, and a display device. The pixel driving circuit comprises: a light emitting element and a driving transistor, a gate of the driving transistor being electrically coupled to a second node, a drain of the driving transistor being electrically coupled to a first node, and a source of the driving transistor being electrically coupled to the light emitting element; a first controlling circuit electrically coupled to the second node; a second controlling circuit electrically coupled to the first node and the second node; a third controlling circuit electrically coupled to a first voltage signal terminal and the first node; a first energy storing circuit electrically coupled to the second node and a third node; a first adjusting circuit electrically coupled to the third node, a fourth node and a second voltage signal terminal.