Shift Register Unit Pull-Up Node Voltage Control for OLED GOA
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Solution Overview
Problem
In OLED display technology, the insufficient charging of Thin-Film Transistors (TFTs) in the pixel region due to voltage leakage in the pull-up node of the Gate Driver on Array (GOA) circuit after a touch event, leading to inefficient display performance.
Innovation Solution
A shift register unit with specific input, pull-down, and control circuits that manage voltage levels across nodes to ensure proper charging of TFTs, including capacitors for voltage bootstrapping and stabilization, effectively maintaining high voltage levels in the pull-up node even after a touch event.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If GOA circuit is used to integrate gate switching circuit on array substrate, then manufacturing cost is reduced and process integration is increased, but voltage leakage occurs in pull-up node after touch event causing insufficient charging of TFTs
Solution Approach 1:
The pull-up node voltage control is segmented into multiple functional blocks: first input circuit receiving STV signal, second input circuit receiving RESET signal, pull-down control circuit with control electrode connected to pull-up node, and separate pull-down circuit. This segmentation allows independent optimization of each circuit's function to prevent voltage leakage while maintaining GOA integration benefits.
Solution Approach 2:
A pull-down control circuit is introduced as an intermediary between the pull-up node and the pull-down circuit. The control electrode of the pull-down control circuit is connected to the pull-up node, allowing it to sense voltage changes and regulate the pull-down operation, thereby preventing excessive voltage leakage and ensuring stable charging of TFTs.
2Device complexity
If simple GOA circuit structure is used, then device complexity is reduced, but charging efficiency of TFTs becomes insufficient after touch event
Solution Approach 1:
The first input circuit and second input circuit are configured to receive STV and RESET signals respectively, preparing the circuit state before the actual charging operation. The pull-down control circuit is pre-configured with its control electrode connected to the pull-up node, enabling it to immediately respond to voltage changes and regulate charging efficiency without delay.
Solution Approach 2:
The pull-down control circuit receives feedback from the pull-up node voltage level through its control electrode connection. This feedback mechanism allows the circuit to automatically adjust the pull-down operation based on the actual voltage state, ensuring optimal charging efficiency of TFTs while maintaining a relatively simple overall circuit structure.
Data Source
AI summary
The embodiments of the present disclosure relate to a shift registers unit and a driving method thereof, and a gate driving device. The shift register unit includes a first and second input circuit, a pull-down control circuit, an output circuit, a pull-down circuit, and a control circuit. The first input circuit provides a first control signal to a pull-up node. The second input circuit provides a second control signal to the pull-up node. The pull-down control circuit provides the voltage of a first voltage terminal to a pull-down node, or controls the voltage of the pull-down node. The output circuit provides a second clock signal to a signal output terminal. The pull-down circuit provides the voltage of the first voltage terminal to the pull-up node and the signal output terminal. The control circuit provides the first input signal to the pull-up node.