OLED Pixel Circuit with Discharge Control for Threshold Voltage Drift
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Solution Overview
Problem
In OLED display panels, the stability of driving currents is crucial for display brightness, but the threshold voltage drift in a-Si TFTs affects brightness and lifetime, leading to reduced current flow and display performance.
Innovation Solution
A pixel circuit comprising a drive circuit, storage circuit, discharge control circuit, storage control circuit, and data writing circuit, which controls the driving current and stores threshold voltage to eliminate the influence of threshold voltage drift, improving display effect and extending the service life of the light-emitting element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a-Si TFTs are used in the pixel circuit, then the manufacturing cost is reduced and the process is simplified, but the threshold voltage drift occurs which affects display brightness and lifetime
Solution Approach 1:
The pixel circuit is divided into multiple functional modules: a drive circuit with switching transistor, a storage circuit with storage capacitor, a discharge control circuit, and a storage control circuit. This segmentation allows the threshold voltage drift to be managed separately through the storage circuit, while the drive circuit can use simpler a-Si TFTs for manufacturing.
Solution Approach 2:
The storage circuit acts as an intermediary between the data writing circuit and the drive circuit. It stores the threshold voltage of the switching transistor and compensates for threshold voltage drift, thereby stabilizing the driving current without requiring complex transistor designs.
2Device complexity
If the threshold voltage drift is not compensated, then the circuit structure remains simple, but the display brightness and lifetime are reduced
Solution Approach 1:
The storage circuit pre-stores the threshold voltage of the switching transistor before the driving operation begins. This preliminary storage action enables the circuit to compensate for threshold voltage drift during operation, extending display lifetime without significantly increasing circuit complexity.
3Device complexity
If the driving current is not stabilized, then the control circuit is simpler, but the display brightness and uniformity deteriorate
Solution Approach 1:
The storage circuit provides feedback by storing the threshold voltage and using it to compensate for drift during the driving operation. This feedback mechanism stabilizes the driving current, ensuring consistent display brightness without requiring complex real-time control circuits.
Data Source
AI summary
A pixel circuit and a method for driving the pixel circuit, a display panel and an electronic device are provided. The pixel circuit includes a drive circuit, a storage circuit, a discharge control circuit, a storage control circuit, and a data writing circuit. The drive circuit is configured to control a driving current for driving a light-emitting element to emit light; the storage circuit is connected to the control terminal of the drive circuit; the discharge control circuit is configured to control a voltage across the storage circuit and to control the second terminal of the drive circuit to discharge; the storage control circuit is configured to control the storage circuit to store a voltage of the drive circuit; the data writing circuit is configured to write a data voltage into the storage circuit to control the drive circuit.