Display Panel Bias Adjustment Module for Threshold Voltage Stability
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Solution Overview
Problem
The internal characteristics of drive transistors in pixel circuits change over time, shifting the threshold voltage and affecting display uniformity in display panels.
Innovation Solution
A display panel with a pixel circuit that includes a drive module and a bias adjustment module, where the bias adjustment module is connected between the drive transistor's terminals and a bias signal terminal, allowing for bias signal adjustment to reduce the potential difference between the gate and drain, thereby stabilizing the threshold voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the drive transistor operates for extended periods, then the display panel can maintain continuous operation, but the threshold voltage of the drive transistor shifts due to internal characteristic changes, affecting display uniformity
Solution Approach 1:
The patent applies preliminary action by introducing a bias adjustment stage before the normal display operation. In this pre-stage, a bias signal is applied to the drive transistor to proactively adjust its threshold voltage characteristics, preventing threshold voltage shift from occurring during subsequent continuous operation. This preliminary adjustment ensures display uniformity is maintained throughout extended operation periods.
Solution Approach 2:
The patent changes the electrical parameters of the drive transistor by applying a bias signal that modifies the threshold voltage. This parameter adjustment compensates for internal characteristic changes that occur during prolonged operation, thereby maintaining consistent display performance and uniformity over time.
2Reliability
If a bias adjustment module is added to the pixel circuit, then the threshold voltage stability is improved, but the device complexity increases
Solution Approach 1:
The bias adjustment module is designed to perform multiple functions within the pixel circuit. It not only adjusts the threshold voltage to maintain stability but also integrates with the existing pixel circuit operations, serving both as a compensation mechanism and part of the overall display control system, thereby reducing the relative impact of added complexity.
Solution Approach 2:
The bias adjustment module acts as an intermediary element between the existing pixel circuit components and the drive transistor. It mediates the electrical characteristics by introducing a controllable bias signal, enabling threshold voltage stabilization without requiring fundamental redesign of the core pixel circuit architecture, thus limiting the increase in overall device complexity.
Data Source
AI summary
Provided are a display panel and a display device. The display panel includes a pixel circuit and a light-emitting element. The pixel circuit includes a drive module and a bias adjustment module. The drive module is configured to provide a drive current to the light-emitting element, and includes a drive transistor. The bias adjustment module is connected between a first terminal of the drive transistor and a bias signal terminal, a control terminal of the bias adjustment module is connected to a first scan signal terminal, and a second terminal of the drive transistor is coupled to the light-emitting element. A working process of the pixel circuit includes a pre-stage, the pre-stage includes a bias adjustment stage, the bias adjustment module is turned on in the bias adjustment stage, and the bias signal terminal provides a bias signal to the first terminal of the drive transistor.