GOA Circuit Transistor Drift Prevention via Pull-Down Control
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Solution Overview
Problem
In GOA circuits, the threshold voltage of transistors tends to drift over time, leading to malfunction and abnormal display performance, especially in high-temperature environments, due to prolonged on-state conditions.
Innovation Solution
The implementation of a GOA circuit with cascaded units, including a forward and reverse scan control module, node signal control module, voltage regulator module, output control module, first and second pull-down modules, and a reset module, which incorporates a second pull-down module to control voltage levels and prevent prolonged on-states, utilizing low temperature polycrystalline silicon thin film transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the transistor is kept on for a long period to maintain GOA circuit operation, then the circuit can continuously drive the display, but the threshold voltage of the transistor drifts causing malfunction and abnormal display
Solution Approach 1:
The patent implements periodic switching of the transistor between on-state and off-state through a control signal that periodically activates a pull-down module. This periodic action prevents continuous on-state operation, thereby avoiding threshold voltage drift while maintaining display driving capability through repeated activation cycles.
Solution Approach 2:
The patent applies preliminary anti-action by introducing a pull-down module that preemptively counteracts threshold voltage drift before it causes malfunction. The control signal periodically activates this module to pull down the transistor gate voltage, preventing the accumulation of threshold voltage shifts that would otherwise lead to circuit failure.
2Productivity
If the transistor operates continuously in high temperature environment, then the display can function normally, but the threshold voltage drift accelerates causing transistor abnormality
Solution Approach 1:
The patent employs periodic switching action that becomes particularly effective in high temperature environments. The control signal periodically activates the pull-down module to counteract thermally accelerated threshold voltage drift, allowing continuous display operation while mitigating the harmful effects of high temperature on transistor stability.
Solution Approach 2:
The patent implements a feedback mechanism where the periodic control signal responds to the cumulative effect of threshold voltage drift. The pull-down module is activated at intervals to correct drift accumulation, creating a feedback loop that maintains transistor performance despite continuous operation in high temperature conditions.
3Device complexity
If the GOA circuit uses conventional transistor control without pull-down modules, then the circuit structure is simpler, but the output fails due to threshold voltage drift
Solution Approach 1:
The patent applies preliminary anti-action by incorporating a pull-down module that preemptively prevents threshold voltage drift from causing output failure. Although this increases circuit complexity, it ensures reliable operation by counteracting drift before it affects the GOA circuit output, particularly in continuous operation scenarios.
Solution Approach 2:
The patent introduces a control signal as an intermediary element that coordinates between the transistor operation and the pull-down module activation. This intermediary control mechanism manages the balance between maintaining simple circuit operation and ensuring output stability through periodic threshold voltage correction.
Data Source
AI summary
The invention provides a GOA circuit and driving method therefor, and a display panel. The GOA circuit includes a GOA unit. The GOA unit includes a forward and reverse scan control module, a node signal control module, a voltage regulator module, an output control module, a first pull-down module, and a second pull-down module. When the second pull-down module is in operation, the forward and reverse scan control module controls the voltage regulator module to be in an off state, so that the GOA circuit has no transistor in the on state for a long time, thus to suppress threshold voltage drift in transistors.