LCD Gate Driver Z-Shape Staging for Pulse Falling Time Delay
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Solution Overview
Problem
The existing overlapping drive mode in LCD panels struggles to address the delay of the falling time of the gate pulse, leading to signal distortion and longitudinal line defects, which affect picture quality.
Innovation Solution
The LCD panel design includes a gate driver with stages arranged in a Z or inverse-Z shape and compensation transistors connected to both ends of each gate line, allowing for the application of gate high voltage during multiple horizontal intervals, thereby reducing the delay of the falling time of the gate pulse by synchronizing gate low voltage with gate high voltage on adjacent lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the overlapping drive mode is used to apply gate high voltage during longer intervals, then the pre-charging effect is enhanced, but the delay of the falling time of the gate pulse cannot be solved
Solution Approach 1:
The gate driver is divided into multiple stages (first through fourth stages) that are sequentially activated. Each stage applies gate high voltage to specific gate lines for a limited duration, and the stages are arranged in a Z-shape or inverse-Z-shape pattern. This segmentation allows the overall gate high voltage application interval to be extended through sequential staging while each individual stage maintains precise control over its activation and deactivation timing, thereby solving the falling time delay problem.
Solution Approach 2:
The compensation transistors are connected to both ends of each gate line and are activated in advance to prepare for the gate pulse transition. By pre-positioning the compensation transistors at both ends of the gate lines and activating them sequentially with the staged gate driver, the system prepares the electrical path before the main gate pulse arrives, reducing the RC delay effect and ensuring faster falling time response.
2Reliability
If the gate driver stages are arranged in a Z or inverse-Z shape with compensation transistors at both ends, then the falling time delay is reduced, but the device complexity increases
Solution Approach 1:
Multiple gate driver stages are merged into a single integrated gate driver structure with a Z-shape or inverse-Z-shape arrangement. The compensation transistors are integrated at both ends of the gate lines within the same gate driver module. This merging approach achieves the complex timing control and dual-end compensation functionality while maintaining a unified device structure, thereby reducing overall device complexity compared to having separate independent control circuits for each function.
3Manufacturing precision
If compensation transistors are connected to both ends of each gate line, then signal distortion is reduced, but manufacturing complexity increases
Solution Approach 1:
The compensation transistors connected to both ends of each gate line serve multiple functions: they provide dual-end compensation for signal integrity, enable sequential activation for RC delay reduction, and work in conjunction with the staged gate driver for precise timing control. This multi-functionality means that a single structural configuration achieves multiple objectives, simplifying the overall manufacturing process compared to implementing separate solutions for each function.
Data Source
AI summary
An LCD panel being driven in an overlapping drive mode by applying a gate high voltage during n horizontal synchronous intervals is disclosed. The LCD panel includes: a plurality of gate lines; and a gate driver configured to include a plurality of stages connected to the plurality of gate lines. The plurality of stages are grouped in a plurality of stage groups each including n stages. Odd-numbered stage groups each allows the n stages to be arranged in a Z shape with having a display area therebetween. Even-number stage groups each allows the n states to be arranged in an inverse-Z shape with having the display area therebetween.