Shift Register Unit Noise Reduction for Stable Gate Driver Signals
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Solution Overview
Problem
In large-sized and high-resolution displays using oxide thin film transistors with higher mobility, the threshold voltage is unstable, leading to negative bias fluctuations and leakage current, which affects the performance of Gate Driver on Array (GOA) technology and results in display defects.
Innovation Solution
A shift register unit is designed with an input subcircuit, output subcircuit, pull-down control subcircuit, pull-down subcircuit, first noise reduction subcircuit, first auxiliary control subcircuit, and second auxiliary control subcircuit, which work together to stabilize the potential of the pull-up node and prevent electricity leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If oxide thin film transistors with higher mobility are used, then transistor mobility is improved, but threshold voltage stability deteriorates causing leakage current
Solution Approach 1:
The patent introduces a noise reduction subcircuit as an intermediary component between the pull-up node and the output. This subcircuit includes a control transistor and a reference voltage generator that actively compensates for threshold voltage fluctuations and leakage current caused by oxide transistor instability, thereby maintaining signal integrity without sacrificing mobility benefits
Solution Approach 2:
The patent implements a feedback mechanism through the noise reduction subcircuit that continuously monitors the pull-up node potential and adjusts the reference voltage accordingly. When leakage current or threshold voltage drift is detected, the feedback loop activates to compensate, ensuring stable output signals despite the inherent instability of oxide transistors
2Adaptability or versatility
If GOA technology is implemented, then integration and design flexibility are improved, but sensitivity to threshold voltage instability increases
Solution Approach 1:
The noise reduction subcircuit serves as a protective intermediary in the GOA architecture, isolating the sensitive pull-up node from external noise and instability. This allows the GOA design to maintain its integration advantages while the subcircuit actively stabilizes signals against threshold voltage fluctuations inherent in oxide transistors
Solution Approach 2:
The patent applies preliminary action by pre-establishing a stable reference voltage through the reference voltage generator before the signal processing occurs. This advance preparation ensures that when oxide transistor instability occurs, the system already has the compensating mechanism in place to maintain signal stability throughout the GOA operation
Data Source
AI summary
The present disclosure provides a shift register unit, a gate driver circuit, and a display device, belonging to the field of display technology, which can solve the problem of unstable threshold voltage and current leakage of thin film transistors in existing shift register units. The shift register unit in the present disclosure includes: an input subcircuit, an output subcircuit, a pull-down control subcircuit, a pull-down subcircuit, a first noise reduction subcircuit, a first auxiliary control subcircuit, and a second auxiliary control subcircuit. The first auxiliary control subcircuit is configured to write the third reference level signal to the pull-down control node when the pull-down node is the first reference level signal, and control the pull-down subcircuit to be closed to control the first noise reduction subcircuit to be open.