LCD Gate Driver Precharge Control Against Capacitive Coupling
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Solution Overview
Problem
The stability of gate drivers in liquid crystal displays (LCDs) is compromised due to capacitive coupling effects, leading to operational failures, particularly in slim border products where control nodes are unstable.
Innovation Solution
The implementation of series-coupled driving stages with specific configurations, including switches and capacitors, that adjust control voltage levels using clock signals to mitigate capacitive coupling effects, ensuring stable operation by maintaining a control voltage at a low level during predetermined time intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional gate driver configurations are used, then the display panel can be manufactured, but the control nodes become unstable due to capacitive coupling effects
Solution Approach 1:
The patent applies preliminary anti-action by introducing a precharge switch and precharge signal that proactively charge the control node before the main switching operation. This preliminary action counteracts the harmful capacitive coupling effects that would otherwise cause voltage instability, thereby improving the reliability of control nodes without requiring larger capacitors.
2Reliability
If larger capacitors are used to stabilize control nodes, then stability improves, but the device size and complexity increase
Solution Approach 1:
The patent implements preliminary action by charging the control node in advance through the precharge switch before the main switching operation occurs. This preliminary charging action ensures that the control node is already at the appropriate voltage level, eliminating the need for larger capacitors to maintain stability during switching operations, thus reducing device complexity while improving reliability.
3Area of stationary object
If the gate driver is designed for slim border products, then the visible area increases, but the control nodes become more susceptible to capacitive coupling
Solution Approach 1:
The patent applies preliminary anti-action by using the precharge switch to charge the control node before switching operations, which counteracts the increased susceptibility to capacitive coupling effects in slim border designs. This allows the gate driver to maintain stability in compact slim border configurations that maximize visible area without compromising control node reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances the operational reliability of the gate driver by reducing disturbances from capacitive coupling, allowing the gate driver to function stably and be applicable to slim border products without the need for large capacitors, thereby improving the overall performance of the display panel.
Implementation Method 1
A first terminal of the first capacitor is coupled to the control node, and a second terminal of the first capacitor is coupled to the second terminal of the first switch
Data Source
AI summary
A display panel includes gate lines and a gate driver. The gate driver includes series coupled driving stages, in which an N-th driving stage of the series-coupled driving stages includes a driving unit and an input control unit. The driving unit transmits a first clock signal according to a control voltage level of a control node, so as to output a gate-driving signal. The input control unit transmits the gate-driving signal outputted from an (N−1)-th driving stage to the control nodes, so as to adjust the control voltage level to one of a first voltage level and a second voltage level. A predetermined time interval is present between a rising edge of the first clock signal and a falling edge of the second clock signal. During the predetermined time interval, the control voltage level is pulled to the first voltage level by the input control unit.