Capacitorless Shift Register Unit for Narrow Bezel LCD Panels
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Solution Overview
Problem
Existing liquid crystal display (LCD) panel gate driver circuits require capacitors for voltage boosting, which occupy significant space and lead to transistor characteristic variations due to high gate voltages, affecting display stability and bezel design.
Innovation Solution
A shift register unit composed of switch elements without capacitors, incorporating input, reset, noise reduction, and output circuits, utilizing N-type and P-type transistors with specific voltage and clock signal control to manage node voltages and reduce noise, allowing for a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If capacitors are used for voltage boosting in gate driver circuits, then voltage boosting function is achieved, but array substrate area increases
Solution Approach 1:
The invention extracts and eliminates the capacitor component from the gate driver circuit, replacing the traditional capacitor-based voltage boosting mechanism with a capacitorless circuit design using transistors and switches, thereby reducing occupied area on the array substrate
Solution Approach 2:
The circuit achieves multiple functions including voltage boosting, noise reduction, and signal driving through a unified capacitorless transistor-based structure, eliminating the need for separate capacitor components and reducing overall circuit area
2Power
If high gate voltages are applied for voltage boosting, then voltage boosting function is achieved, but transistor characteristic variations occur
Solution Approach 1:
The circuit incorporates noise reduction circuits and voltage control mechanisms that preemptively stabilize transistor operating conditions before high voltage is applied, cushioning against voltage-induced characteristic variations and ensuring stable transistor performance
Solution Approach 2:
The invention dynamically adjusts voltage parameters and timing sequences to optimize transistor operating conditions, changing voltage levels and durations to prevent transistor characteristic degradation while maintaining necessary voltage boosting functionality
3Stability of the object's composition
If capacitors are used in shift register units, then voltage holding function is achieved, but device area increases
Solution Approach 1:
The invention removes capacitors from the shift register unit and replaces the voltage holding function with transistor-based charge storage and switching mechanisms, achieving the same voltage holding capability without the area overhead of capacitor components
Solution Approach 2:
The patent substitutes the passive electrical storage mechanism (capacitor) with an active transistor-based control system that achieves voltage holding through controlled charge transfer and switching, enabling compact integration without sacrificing voltage stability
Data Source
AI summary
The present disclosure provides a shift register unit, which includes an input circuit, a reset circuit, a noise reduction circuit, and an output circuit. The input circuit is configured to control a voltage of a first node based on a first input signal and a second input signal, and control a voltage of a second node based on a first voltage and the voltage of the first node. The reset circuit is configured to reset the voltage of the first node and the voltage of the second node. The noise reduction circuit is configured to maintain a reset voltage of the first node and a reset voltage of the second node. The output circuit is configured to provide, for an output terminal of the output circuit, a second clock signal from a second clock signal terminal or the second voltage. The shift register unit is composed of switch elements.