Display Panel Threshold Voltage Drift Compensation
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Solution Overview
Problem
In existing display panels, the threshold voltage of drive transistors drifts over time due to changes in internal characteristics, affecting display uniformity.
Innovation Solution
A display panel with a pixel circuit that includes a light emitting control module, a drive module, and a compensation module. The compensation module adjusts the threshold voltage of the drive transistor by writing a power supply signal into the drain of the drive transistor during a bias stage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive transistor operates continuously in existing display panels, then the display function is maintained, but the threshold voltage drifts over time causing display uniformity degradation
Solution Approach 1:
The patent applies preliminary action by introducing a bias stage before the light emitting stage, where the drive transistor is pre-biased with a specific voltage (e.g., -3V to -10V) to counteract anticipated threshold voltage drift. This preliminary voltage adjustment ensures that when the transistor enters the light emitting stage, its threshold voltage is already compensated, maintaining display uniformity throughout operation.
Solution Approach 2:
The patent implements periodic action by alternating between bias stages and light emitting stages in a cyclic manner. During each bias stage, the drive transistor receives a compensating voltage to reset its threshold voltage, and during light emitting stages, it performs its display function. This periodic cycling continues throughout the display's operation, continuously counteracting threshold voltage drift and maintaining display uniformity.
2Reliability
If a bias stage is added to compensate threshold voltage, then display uniformity is improved, but the operating cycle becomes more complex
Solution Approach 1:
The patent merges the bias stage and light emitting stage into a unified operating cycle managed by a single light emitting control module. The control module generates both the bias voltage and the light emitting voltage, and the drive transistor seamlessly transitions between the two states. This integration reduces the need for separate control circuits and simplifies the overall system architecture while maintaining the benefits of threshold voltage compensation.
Data Source
AI summary
Provided are a display panel, a driving method thereof and a display device. The display panel includes: a pixel circuit and a light-emitting element, where the pixel circuit includes a light emitting control module, a drive module and a compensation module; the light emitting control module includes a first light emitting control module configured to selectively provide a first power supply signal for the drive module; the drive module is configured to provide a drive current for the light-emitting element and comprises a drive transistor; the compensation module is configured to compensate a threshold voltage of the drive transistor; and a working process of the pixel circuit includes a light emitting stage and a bias stage.