Embedded Scan Driver Compensation Voltage Threshold Stability
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Solution Overview
Problem
The reliability of embedded scan drivers in display devices, such as OLED and liquid crystal displays, is compromised due to degradation factors like temperature, bias voltage, and stress time, which affect the threshold voltage of thin film transistors, leading to leakage currents and poor drive performance.
Innovation Solution
A compensation voltage is supplied to the scan driver through a compensation gate electrode, artificially controlling the threshold voltage of transistors to improve the driving margin and maintain the gate-to-source voltage at a stable level, thereby enhancing the reliability of the scan driver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an embedded scan driver is formed in the display panel using thin film transistors, then the integration is improved, but the reliability deteriorates due to threshold voltage changes from temperature, bias voltage, and stress time
Solution Approach 1:
The patent applies parameter changes by introducing a compensation voltage that dynamically adjusts the threshold voltage of thin film transistors in the embedded scan driver. This compensation voltage counteracts the threshold voltage shifts caused by temperature, bias voltage, and stress time, thereby maintaining reliable operation while preserving the integrated design
2Ease of manufacture
If thin film transistors are used in the embedded scan driver, then the manufacturing is simplified, but the threshold voltage stability deteriorates under temperature and stress conditions
Solution Approach 1:
The patent changes the electrical parameter of the thin film transistor by applying a compensation voltage to the gate electrode. This dynamically adjusts the threshold voltage to compensate for instabilities caused by temperature and stress, maintaining stable operation while keeping the simple thin film transistor manufacturing process
3Device complexity
If the scan driver is embedded in the display panel, then the device complexity is reduced, but the leakage current increases due to threshold voltage degradation
Solution Approach 1:
The patent changes the gate voltage parameter by introducing a compensation voltage that counteracts threshold voltage degradation. This prevents leakage current generation by maintaining proper voltage levels across the thin film transistors in the embedded scan driver, keeping the device simple while eliminating harmful leakage effects
Data Source
AI summary
A display device includes a display panel and a scan driver including transistors formed in a non-display area of the display panel. A compensation voltage is supplied to the scan driver through a compensation gate electrode included in at least one transistor of the scan driver. Namely, the at least one transistor includes a gate electrode, to which a signal or a voltage for activating a channel is supplied, and the compensation gate electrode, to which the compensation voltage for recovering a threshold voltage is supplied.