OLED Pixel Circuit Threshold Compensation via Storage Capacitor Potential
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Solution Overview
Problem
The threshold voltage drift of the drive transistor in OLED display pixel circuits leads to display non-uniformity due to leakage currents, and existing pixel circuits with threshold compensation functions have complex structures that hinder high pixels per inch (PPI) and fail to satisfy high-transmittance region requirements.
Innovation Solution
A pixel circuit comprising a drive transistor, storage capacitor, data writing module, and threshold compensation module, where the threshold compensation module adjusts the storage capacitor's potential to compensate for the threshold voltage of the drive transistor, reducing the influence of threshold voltage drift on luminous brightness and improving display uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a threshold compensation function is added to the pixel circuit, then display uniformity is improved, but circuit structure becomes complex
Solution Approach 1:
The patent merges the threshold compensation function with the existing storage capacitor by adjusting the potential of the second plate of the storage capacitor. Instead of adding a separate compensation circuit, the compensation is achieved by controlling the voltage potential of the storage capacitor's second plate through a control transistor, thereby integrating multiple functions into existing components and reducing overall circuit complexity while maintaining display uniformity.
2Productivity
If circuit components are reduced for high PPI, then resolution is improved, but threshold compensation capability is lost
Solution Approach 1:
The storage capacitor is designed to serve dual functions: traditional data storage and threshold voltage compensation. By controlling the potential of the second plate of the storage capacitor, the same component performs both data retention and compensation for threshold voltage drift, eliminating the need for separate compensation circuits and enabling high PPI displays while maintaining threshold stability.
3Reliability
If a dual-potential adjustment mechanism is implemented, then threshold voltage compensation is achieved, but circuit complexity increases
Solution Approach 1:
The control transistor automatically adjusts the potential of the second plate of the storage capacitor based on the threshold voltage characteristics of the drive transistor. The mechanism uses the transistor's own threshold voltage properties to generate the appropriate compensation potential, enabling self-service compensation without requiring complex external control circuits or additional adjustment mechanisms.
Data Source
AI summary
Provided are a pixel circuit and a drive method thereof, a display panel and a display device. The pixel circuit includes: a drive transistor, a storage capacitor, a data writing module, a threshold compensation module, and an organic light emitting element. The data writing module is electrically connected to a gate of the drive transistor and a first plate of the storage capacitor, and is configured to write a data signal to the gate of the drive transistor and the first plate of the storage capacitor at a data writing phase. The threshold compensation module is electrically connected to a second plate of the storage capacitor, and is configured to adjust a potential of the second plate of the storage capacitor to a first potential at the data writing phase, and adjust the potential of the second plate of the storage capacitor to a second potential.