Dual Transparent Electrode Driving Method for LCD Persistence
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Solution Overview
Problem
Liquid crystal display devices face a persistence phenomenon due to long-term DC voltage application, leading to shortened lifespan, and existing driving methods do not effectively address this issue.
Innovation Solution
A display device and driving method that utilize a capacitive coupling system with a first and second transparent electrode, a first and second switch, and a common electrode, where the first switch is connected to the signal line and first scanning line, and the second switch is connected to the signal line and second scanning line, allowing for alternating voltage application to prevent persistence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DC voltage is applied to the liquid crystal layer for a long time, then the liquid crystal display device can maintain a stable display state, but the tilt of the liquid crystal layer becomes fixed and a persistence phenomenon occurs, leading to a shortened life of the liquid crystal layer
Solution Approach 1:
The patent applies periodic action by inverting the voltage polarity applied to the liquid crystal layer at regular intervals. The voltage applied to the pixel electrode is alternated between positive and negative polarity, preventing the liquid crystal molecules from maintaining a fixed tilt state. This periodic voltage inversion eliminates the persistence phenomenon while maintaining stable display operation throughout the device lifetime.
2Reliability
If voltage is alternated to prevent persistence phenomenon, then the life of the liquid crystal layer is extended, but power consumption increases due to frequent voltage changes
Solution Approach 1:
The patent segments the voltage control into two independent transparent electrodes (first and second transparent electrodes) that can be controlled separately. By independently adjusting the voltage applied to each electrode, the system can implement voltage inversion to prevent persistence while optimizing power consumption. The segmentation allows for more flexible voltage management compared to a single electrode system.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the capacitance values of the first and second transparent electrodes through capacitive coupling. By changing the capacitance parameters of the auxiliary capacitance lines connected to each electrode, the system can control the amount of voltage change and inversion timing, thereby preventing persistence phenomenon while minimizing power consumption increases.
3Device complexity
If a single transparent electrode is used for voltage application, then the device structure is simple, but effective voltage inversion to prevent persistence cannot be achieved
Solution Approach 1:
The patent divides the single electrode system into two separate transparent electrodes (first and second transparent electrodes) positioned on opposite sides of the liquid crystal layer. This segmentation enables independent voltage control of each electrode, making it possible to apply voltage inversion effectively. The two-electrode configuration allows one electrode to maintain a reference voltage while the other undergoes polarity inversion, achieving persistence prevention with a relatively simple structural extension.
Solution Approach 2:
The patent introduces auxiliary capacitance lines as intermediaries connected to the first and second transparent electrodes. These capacitance lines serve as mediators that store and transfer charge during voltage inversion cycles, enabling smooth polarity switching without direct complex circuit connections to each electrode. The intermediary capacitance elements simplify the overall control architecture while achieving the desired voltage inversion effect.
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
The method reduces power consumption and extends the lifespan of liquid crystal display devices by effectively preventing persistence through controlled voltage inversion and capacitance coupling, enhancing display quality and screen size.
Implementation Method 1
a first transparent electrode capacitively coupled to the second transparent electrode
Data Source
AI summary
According to one embodiment, a display device includes a first scanning line, a second scanning line, a signal line, a capacitive line and a pixel including a pixel electrode, a first transparent electrode connected to the capacitive line, a second transparent electrode capacitively coupled to the pixel electrode, a first switch, and a second switch. The first transparent electrode is capacitively coupled to the second transparent electrode. The first switch is electrically connected to the signal line, the pixel electrode, and the first scanning line. The second switch is electrically connected to the signal line, the second transparent electrode, and the second scanning line.