GOA Circuit Pull-Down Control for Touch-Period Leakage Stability
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Solution Overview
Problem
The NMOS GOA circuits in liquid crystal display devices are prone to instability and high temperature reliability issues, particularly in in-cell touch panels, leading to split screen phenomena due to leakage currents and insufficient stability during touch periods.
Innovation Solution
A GOA circuit design incorporating a pull-up control circuit, pull-up and pull-down control circuits, a gate opening unit, and capacitors to maintain stable node potentials and prevent leakage paths during touch periods, using a cascaded structure with NMOS, PMOS, and CMOS circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If NMOS GOA circuit is used to eliminate PP layer and reduce cost, then manufacturing cost is reduced and yield is improved, but high temperature reliability deteriorates and split screen phenomenon occurs
Solution Approach 1:
The patent changes the electrical parameters of the GOA circuit by introducing a second pull-down control circuit unit that dynamically adjusts the potential of the second node. This parameter adjustment prevents the leakage current accumulation that causes split screen, while maintaining the NMOS circuit structure that provides manufacturing advantages.
Solution Approach 2:
The second pull-down control circuit unit acts as an intermediary component that mediates between the clock signals and the internal nodes of the GOA circuit. By controlling the potential of the second node through this intermediary unit, the patent prevents direct leakage effects from causing split screen while keeping the overall NMOS architecture.
2Adaptability or versatility
If touch pause level is maintained for long period, then touch function is enabled, but leakage current accumulates and GOA stability deteriorates
Solution Approach 1:
The second pull-down control circuit unit performs periodic action by periodically pulling down the second node potential in synchronization with the clock signals. This periodic intervention prevents continuous leakage current accumulation during the touch pause period, maintaining GOA stability while enabling touch functionality.
Solution Approach 2:
The circuit performs preliminary action by proactively managing the potential of the second node before leakage current can cause instability. The pull-down control operates in advance to prevent the accumulation of leakage effects, ensuring stability is maintained throughout the touch period.
3Reliability
If thin film transistor leakage current is present, then device realism is maintained, but gradual transmission stability deteriorates during touch period
Solution Approach 1:
The patent converts the harmful effect of leakage current into a beneficial control mechanism. By using the second pull-down control circuit unit to actively manage the second node potential in response to leakage current, the circuit transforms the unavoidable leakage into a controllable parameter that maintains stability rather than degrades it.
Data Source
AI summary
The present disclosure provides a GOA circuit and a display panel, wherein the GOA circuit is provided with a second pull-down control circuit unit (104). Combined with a timing diagram, during a touch period, for a gradual transmission first node (Q), through a third control signal (GAS2) and a second control signal (D2U), the first node (Q) changes from a low-level signal to a high-level signal, so that two leakage paths of the first node (Q) disappear, and there is no leakage path at the first node Q during touch, thereby maintaining stability of the first node Q.