Scan Driver Compensation for Transistor Threshold Shifts
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Solution Overview
Problem
Conventional embedded scan drivers in display devices face reliability issues due to characteristic deterioration of thin film transistors when operating in extreme environmental conditions, such as high or low temperatures, leading to threshold voltage shifts and unwanted multiple outputs.
Innovation Solution
A scan driver configuration that includes a sensor circuit unit to sense internal and external environmental conditions and generate a compensation circuit control signal, which is used by a compensation circuit unit to adjust the outputs of the shift register stages, thereby compensating for transistor characteristic deterioration and maintaining reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If an embedded scan driver is used in the display panel, then the integration is improved, but the reliability deteriorates under extreme environmental conditions
Solution Approach 1:
The scan driver is divided into two separate parts: the shift register is formed inside the display panel in the non-display area, while the level shifter is formed outside the display panel on a separate substrate. This segmentation allows each component to be optimized independently, with the level shifter being replaceable based on environmental conditions, thus improving reliability without sacrificing integration.
Solution Approach 2:
The invention introduces a dynamic configuration where the level shifter can be selectively replaced or adjusted based on environmental conditions. The scan driver transitions from a fixed embedded configuration to a flexible hybrid configuration, allowing the system to adapt to extreme environmental conditions by replacing the level shifter component, thereby maintaining reliability.
2Device complexity
If the shift register is fully embedded in the display panel, then the device complexity is reduced, but the adaptability to environmental conditions deteriorates
Solution Approach 1:
By segmenting the scan driver into embedded shift register and external level shifter, the invention achieves a balance between simplicity and adaptability. The embedded portion maintains low complexity, while the external level shifter provides environmental adaptability.
Solution Approach 2:
The level shifter formed outside the display panel serves multiple functions: it can be selectively replaced for different environmental conditions, it provides signal level conversion, and it enables the scan driver to operate in both standard and extreme environments. This multi-functionality enhances adaptability without significantly increasing overall device complexity.
Data Source
AI summary
A scan driver and display device using the same are disclosed. The display device includes display panel, a data driver configured to supply a data signal to the display panel, and a scan driver formed in a non-display area of the display panel, including a shift register composed of a plurality of stages and a level shifter formed outside the display panel, and configured to supply a scan signal to the display panel using the shift register and the level shifter. The scan driver comprises: a sensor circuit unit configured to sense internal and external environmental conditions and generate a compensation circuit control signal on the basis of a sensed result; and a compensation circuit unit generating a compensation signal to compensate outputs of the plurality of stages in response to the compensation circuit control signal.