Pixel Circuit Bias Compensation for Threshold Voltage Drift
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Solution Overview
Problem
The drift of the threshold voltage of the driving transistor in display panels affects the display effect over time, leading to issues such as reduced driving current and display uniformity.
Innovation Solution
A display panel design incorporating a pixel circuit with a driving transistor, a bias adjustment module, a threshold compensation module, and a first capacitor to stabilize the threshold voltage by adjusting the gate potential through bias and threshold compensation mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the display panel operates for extended service time, then the driving transistor provides continuous driving current, but the threshold voltage of the driving transistor drifts, affecting display effect
Solution Approach 1:
The patent implements preliminary compensation actions before threshold voltage drift significantly impacts display quality. The bias adjustment module proactively adjusts the gate potential of the driving transistor based on detected threshold voltage changes, and the threshold compensation module compensates for drift by adjusting the threshold voltage through dedicated compensation circuits. This preliminary intervention prevents degradation of display effect during extended service time.
Solution Approach 2:
The patent establishes feedback mechanisms where the pixel circuit continuously monitors the threshold voltage of the driving transistor and adjusts compensation parameters accordingly. The bias adjustment module receives feedback on threshold voltage drift and dynamically adjusts the gate potential to maintain stable operation. This closed-loop feedback ensures reliability is maintained throughout the extended service time.
2Duration of action of stationary object
If the threshold voltage of the driving transistor drifts, then the display panel continues to operate, but the driving current becomes unstable, reducing display uniformity
Solution Approach 1:
The bias adjustment module performs preliminary adjustment of the gate potential before driving current instability occurs. By detecting early signs of threshold voltage drift and proactively adjusting the gate potential through the bias adjustment module, the system prevents driving current instability and maintains display uniformity throughout continuous operation.
Solution Approach 2:
The patent dynamically changes electrical parameters to compensate for threshold voltage drift. The bias adjustment module changes the gate potential parameter, while the threshold compensation module adjusts the threshold voltage parameter, based on detected drift conditions. These parameter changes maintain stable driving current and display uniformity during continuous operation.
3Reliability
If the pixel circuit includes bias adjustment and threshold compensation modules, then the threshold voltage stability improves, but the device complexity increases
Solution Approach 1:
The patent designs the bias adjustment module and threshold compensation module to serve multiple functions within the pixel circuit. These modules not only compensate for threshold voltage drift but also maintain driving current stability and ensure display uniformity across extended service time. By making these compensation modules multi-functional, the patent reduces the need for separate dedicated circuits for each function, thereby mitigating the increase in device complexity while maintaining improved reliability.
Data Source
AI summary
Provided are a display panel and a display device. The display panel comprises a pixel circuit and a light-emitting element. In the pixel circuit, a gate of a driving transistor is electrically connected to a first node, and a first electrode of the driving transistor is electrically connected to a second node. A bias adjustment module comprises a bias transistor, a gate of the bias transistor is electrically connected to a first scanning terminal, and the bias transistor is electrically connected between a first signal terminal and a fourth node. The first signal terminal is configured to provide a first bias signal. A first capacitor is electrically connected between the fourth node and the first node. A control terminal of a threshold compensation module is electrically connected to a second scanning terminal.