Scan Driving Circuit Resetting Control Signal Node
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Solution Overview
Problem
Conventional liquid crystal display devices face failures due to residual positive charges at the control signal node, leading to competition between thin film transistors and the reset signal, which prevents normal reset of the control signal node and scan driving signal.
Innovation Solution
A scan driving circuit with an input module, resetting module, latching module, logic processing module, and output module, utilizing controllable switches and inverters to process and latch signals, ensuring the control signal node is reset by controlling the fifth controllable switch to turn on during a low reset signal, preventing voltage from the turn-off terminal from being applied.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reset signal is used to reset the control signal node and scan driving signal, then the circuit should be reset normally, but residual positive charges at the control signal node cause competition between thin film transistors, preventing normal reset operation
Solution Approach 1:
The patent applies preliminary anti-action by introducing a pre-reset signal that activates before the main reset signal. This pre-reset signal performs preliminary discharge of residual positive charges at the control signal node, preventing the harmful competition effect between thin film transistors before the main reset operation begins. The pre-reset mechanism counteracts the potential harmful effect in advance, ensuring clean reset operation.
Solution Approach 2:
The patent uses an intermediary approach by introducing a dedicated pre-reset signal as a mediator between the residual charges and the main reset operation. This intermediary signal facilitates the safe removal of residual positive charges through a controlled discharge path, preventing direct conflict between the reset signal and residual charges that would cause transistor competition.
2Stability of the object's composition
If the control signal node has residual positive charges from the previous frame, then the node is maintained at logic high level, but this causes competition between thin film transistors controlled by different signals
Solution Approach 1:
The pre-reset signal performs preliminary action by discharging residual positive charges before the main reset operation, preventing the control signal node from being incorrectly maintained at logic high level. This preliminary discharge action eliminates the condition that would lead to transistor competition, ensuring both voltage stability and operational reliability.
Solution Approach 2:
The patent applies preliminary action by activating the pre-reset signal in advance of the main reset signal. This preliminary action prepares the control signal node by removing residual charges that would interfere with the subsequent reset operation, ensuring the node is in the correct state before the main reset begins.
3Reliability
If the reset signal does not work normally due to transistor competition, then the control signal node and scan driving signal are not reset, but this causes scan driving circuit failure
Solution Approach 1:
The pre-reset signal performs preliminary anti-action by eliminating the transistor competition condition before the main reset signal operates. By discharging residual positive charges in advance, it prevents the harmful interaction between reset signal and residual charges, ensuring the reset function works reliably without causing circuit failure.
Solution Approach 2:
The patent applies beforehand cushioning by providing a protective pre-reset operation that cushions against the potential failure mode. The pre-reset signal acts as a protective measure that prevents the harmful transistor competition from occurring in the first place, ensuring the main reset operation can proceed without risk of circuit failure.
Data Source
AI summary
The invention provides a scan driving circuit and a liquid crystal display device. The scan driving circuit includes: an input module for calculating a preceding-stage control signal, first and second clock signals to obtain a first control signal; a resetting module for resetting a control signal node according to a reset signal; a latching module for calculating the first control signal, the first and second clock signals to obtain a second control signal; a logic processing module for performing a logic calculation on the second control signal and a third clock signal to obtain a logic control signal; an output module for calculating the logic control signal to obtain a scan driving signal; and a scan line for receiving and transmitting the scan driving signal to a pixel unit, to reset the control signal node and the scan driving signal and thereby avoid the failure of scan driving circuit.