Dynamic Impedance Control for Rapid LCD Capacitor Discharge
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Solution Overview
Problem
Conventional power circuits for LCDs require a long time to discharge the capacitor when turned off, leading to a prolonged convergence of the voltage at the counter electrode to 0V, due to the need for large capacitance and resistance values, which is inefficient.
Innovation Solution
A power circuit with a first voltage adjuster for AC output and a second for DC output, where the impedance between the first output terminal and the first voltage adjuster is controlled to be higher when power is turned off, and a different potential is supplied to the second output terminal, allowing for rapid discharge of the capacitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large capacitance and resistance values are used in the power circuit, then the capacitor can be discharged and voltage can be applied to the counter electrode, but the discharge time is prolonged and the convergence to 0V is delayed
Solution Approach 1:
The impedance between the first output terminal and the first voltage adjuster is dynamically changed based on the power state. When power is turned off, the impedance level is increased compared to when power is on, enabling faster discharge of the capacitor without affecting normal operation during powered state.
Solution Approach 2:
The patent changes the impedance parameter of the power circuit based on the power state. By controlling the impedance to be higher when power is turned off, the discharge rate of the capacitor is increased, reducing the time required for voltage convergence to 0V.
2Productivity
If the impedance between the first output terminal and the first voltage adjuster is kept low, then the circuit operates efficiently during normal use, but the capacitor discharge speed is reduced when power is turned off
Solution Approach 1:
The impedance is made dynamic rather than fixed, allowing it to adapt to different operational states. During normal operation, the impedance remains low for efficient power delivery, while during shutdown, the impedance increases to enable rapid capacitor discharge.
3Device complexity
If a different potential is not supplied to the second output terminal, then the circuit structure remains simple, but the capacitor cannot be rapidly discharged when power is turned off
Solution Approach 1:
When power is turned off, a different potential is supplied to the second output terminal in advance to create a voltage difference that accelerates the discharge process. This preliminary action ensures rapid voltage convergence without requiring complex additional circuitry.
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 enables quick stabilization of the AC voltage when turned on and rapid discharge to ground potential when turned off, improving the efficiency of voltage application and shutdown in LCDs.
Implementation Method 1
Power circuit which outputs and applies an AC voltage and a DC voltage to respective terminals of a capacitor
Data Source
AI summary
A power circuit outputs and applies an AC voltage and a DC voltage to respective terminals of a capacitor, so as to obtain an AC output voltage shifted in accordance with the DC voltage component. The power circuit includes a first voltage adjuster for outputting an AC voltage, a second voltage adjuster for outputting a DC voltage, a first output terminal which outputs the AC voltage from the first voltage adjuster, and a second output terminal which outputs the DC voltage from the second voltage adjuster. The first output terminal is connected to one end of the capacitor, while the second output terminal is connected to the other end of the capacitor. The power circuit controls impedance between the first output terminal and the first voltage adjuster.