AMOLED Pixel Driving Circuit 6T1C Structure Electrical Property Recovery
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Solution Overview
Problem
The traditional AMOLED pixel driving circuit with a 2T1C structure lacks compensation, causing the driving thin film transistor to operate in a long-term positive bias state, leading to threshold voltage shift and degraded display quality.
Innovation Solution
The proposed AMOLED pixel driving circuit employs a 6T1C structure with additional transistors and a capacitor to control light emitting time and electrical property recovery, using a light emitting control signal and electrical property recovery signal to manage the bias state of the drive thin film transistor, ensuring it operates in a negative bias state after emission to stabilize brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the traditional 2T1C pixel driving circuit structure is used, then the device complexity is reduced and manufacturing is easier, but the drive thin film transistor operates in long-term positive bias state causing threshold voltage shift and display quality degradation
Solution Approach 1:
The pixel driving circuit is segmented into multiple functional modules: switching transistor T20 for signal input, drive transistor T10 for current control, compensation transistor T30 for threshold voltage compensation, and emission control transistor T40 for light output timing. Each transistor performs a specific function, allowing the circuit to address threshold voltage shift through dedicated compensation mechanisms while maintaining manufacturing feasibility through modular design
Solution Approach 2:
The circuit changes the operating parameters of the drive transistor by implementing a compensation mechanism that actively adjusts for threshold voltage shifts. The compensation transistor T30 and associated capacitors modify the gate voltage parameters to counteract the positive bias effect, allowing the drive transistor to maintain stable operation despite prolonged operation
2Device complexity
If the 2T1C pixel driving circuit is used, then the circuit structure is simpler, but the drive thin film transistor experiences threshold voltage shift leading to unstable light emitting brightness
Solution Approach 1:
The compensation transistor T30 implements a feedback mechanism where the gate of T30 receives a compensation signal that is adjusted based on the operating state of the drive transistor T10. This feedback loop continuously counteracts threshold voltage shifts, stabilizing the current through the OLED and maintaining consistent brightness over time
Solution Approach 2:
The circuit performs preliminary compensation actions by pre-adjusting the gate voltage of the drive transistor before the threshold voltage shift significantly impacts brightness. The compensation mechanism proactively counteracts the positive bias effect during the pixel operation cycle, preventing brightness instability before it occurs
3Stability of the object's composition
If additional transistors and capacitors are added to implement electrical property recovery, then the stability of light emitting brightness is improved, but the device complexity increases
Solution Approach 1:
The circuit merges multiple functions into a unified 6T1C architecture where compensation, emission control, and drive functions are integrated within the pixel structure. By combining these functions into a single coordinated system rather than separate circuits, the design achieves brightness stability while limiting the increase in device complexity through functional integration
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
This solution effectively recovers the electrical properties of the drive thin film transistor, maintaining consistent light emitting brightness and enhancing display quality by preventing long-term positive bias operation.
Implementation Method 1
When the electrical current flows through the organic light emitting diode, the organic light emitting diode emits light
Data Source
AI summary
The present invention provides an AMOLED pixel driving circuit and a pixel driving method which utilize the 6T1C structure driving circuit, wherein the fourth thin film transistor (T4) is located between a gate (G) of the first thin film transistor (T1) and a power source negative voltage (VSS), and controls writing the power source negative voltage (VSS) to the gate (G) of the first thin film transistor (T1) by receiving an electrical property recovery control signal (CS), and the fifth thin film transistor (T5) and the sixth thin film transistor (T6) are electrically coupled to a drain (D) and a source (S) of the first thin film transistor (T1), respectively, and control writing a reference negative voltage (Vref) to the drain (D) and the source (S) of the first thin film transistor (T1) with the electrical property recovery control signal (CS).