Display Panel Scan Driver Node Control for Floating Voltage Stability
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Solution Overview
Problem
Display panels face issues with unstable operation due to floating nodes in scan drivers, which can be affected by external noise, leading to abnormal operations and reduced transistor lifespan due to persistent charges.
Innovation Solution
A display panel and method that includes a shift register with pull-up and pull-down transistors and a node controller to selectively apply reference voltages to nodes, ensuring stable operation by discharging floating nodes during power-off sequences, thereby reducing noise impact and extending transistor lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If floating nodes are left unbiased during scan driver operation, then device complexity is reduced, but stability is worsened due to susceptibility to external noise
Solution Approach 1:
A node controller is introduced as an intermediary component that actively manages floating nodes by applying reference voltages when needed. This mediator resolves the contradiction by providing stability only when necessary, rather than continuously biasing all nodes which would increase complexity.
Solution Approach 2:
The node controller preliminarily identifies which nodes will become floating before they are left unbiased, and applies reference voltages in advance to prevent noise susceptibility. This preliminary action ensures stability is maintained during critical periods while allowing complexity reduction during non-critical periods.
2Use of energy by moving object
If remaining charges are not discharged from floating nodes, then energy consumption is reduced, but reliability is worsened due to transistor stress
Solution Approach 1:
Instead of continuously discharging charges which would consume excessive energy, the node controller implements periodic action by discharging remaining charges only during specific periods such as vertical blanking periods or power-off sequences. This periodic discharge maintains reliability while minimizing energy consumption.
Solution Approach 2:
The system applies preliminary anti-action by discharging charges before they can cause significant transistor stress or damage. By proactively removing charges during blanking periods, the system prevents the accumulation of harmful charges that would otherwise reduce transistor lifespan.
3Stability of the object's composition
If reference voltages are continuously applied to all nodes, then stability is improved, but energy consumption increases
Solution Approach 1:
Instead of applying reference voltages uniformly to all nodes continuously, the node controller implements local quality by selectively applying reference voltages only to specific floating nodes that require stabilization. This localized approach maintains necessary stability while minimizing unnecessary energy consumption from continuously biasing all nodes.
Data Source
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AI summary
A display panel and a method of driving the same are disclosed. The display panel includes a a shift register with a plurality of stages configured for shifting and outputting a scan pulse for a plurality of scan lines. Each stage includes a pull-up transistor and a pull-down transistor coupled in series and defining an output node therebetween, a driver with a first node coupled to a gate electrode of the pull-up transistor and a second node coupled to a gate electrode of the pull-down transistor; and a node controller coupled to the first node, the second node, and the output node. In each stage, the node controller is configured for selectively applying a reference voltage at the first node and the second node in response to a control signal.