Display Device Driving Transistor S-Factor and On-Current Optimization
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Solution Overview
Problem
Transistors in display devices face a trade-off where improving one device performance factor, such as sub-threshold swing value (S-Factor), leads to a deterioration in others like on-current and mobility, particularly affecting image quality in subpixels.
Innovation Solution
A display device and driving method that enhance the S-Factor of driving transistors in subpixels while increasing on-current and mobility, utilizing a circuit configuration with multiple transistors to control node connections and voltages, allowing the driving transistor to operate as a double gate during certain states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sub-threshold swing value (S-Factor) is increased, then the switching performance is improved, but on-current and mobility are reduced
Solution Approach 1:
The patent divides the driving transistor into multiple functional segments by introducing first and second control transistors. These control transistors separately manage different aspects of transistor operation: one controls the gate-body connection to optimize S-Factor, while the other controls source/drain connections to maintain on-current. This segmentation allows independent optimization of conflicting parameters without compromising overall performance.
Solution Approach 2:
The patent implements dynamic control of transistor connections through control transistors that switch between different operational states. The body of the driving transistor is dynamically connected to different nodes (first node, second node, or floating) based on operational requirements. This dynamic reconfiguration enables the transistor to adapt its characteristics in real-time, achieving both high S-Factor and high on-current at different moments.
2Reliability
If the sub-threshold swing value (S-Factor) is increased, then the switching performance is improved, but mobility is reduced
Solution Approach 1:
The patent segments the control functions by introducing dedicated control transistors. The first control transistor manages gate-body connections to improve S-Factor, while the second control transistor manages source/drain connections to maintain mobility. This functional segmentation allows each control element to optimize specific parameters without negatively impacting overall transistor performance.
Solution Approach 2:
The patent employs dynamic connection control where the body of the driving transistor is selectively connected to different nodes based on operational phase. During switching operations, the body is connected to enhance S-Factor; during high-speed operation phases, connections are configured to maintain mobility. This temporal separation of optimization goals resolves the contradiction between S-Factor and mobility.
3Adaptability or versatility
If a single transistor configuration is used, then the device complexity is low, but the ability to satisfy multiple device performance factors simultaneously is limited
Solution Approach 1:
The patent makes the control transistors multi-functional by designing them to perform multiple tasks. The first control transistor not only controls gate-body connections for S-Factor optimization but also participates in overall transistor switching control. The second control transistor manages both source/drain connections and contributes to maintaining on-current and mobility. This multi-functionality reduces the need for additional dedicated components, balancing enhanced performance capability with controlled circuit complexity.
Data Source
AI summary
Embodiments of the present disclosure relate to a display device and a driving method of the display device. More particularly, a subpixel includes a first control transistor for controlling a connection between a body of a driving transistor and a first node of the driving transistor, and a second control transistor for controlling a connection between the body of the driving transistor and a second node of the driving transistor, so that it is possible to improve mobility and on-current performance while increasing a S-factor of the driving transistor.