Display Device Polarity Inversion via Auxiliary Electrode
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Solution Overview
Problem
Liquid crystal display devices face issues with image lag and reduced lifespan due to prolonged application of direct current voltage, which leads to fixed inclination of the liquid crystal layer, and existing driving methods like capacity coupling do not effectively address these problems.
Innovation Solution
A display device with a pixel structure including a pixel electrode, an auxiliary electrode for electrostatic capacitive coupling, and switches, where control signals are used to alternate the voltage applied to the pixel and auxiliary electrodes, allowing for efficient polarity inversion and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If direct current voltage is applied to the liquid crystal layer for a long period, then the liquid crystal molecules maintain a stable alignment, but image lag occurs and the liquid crystal layer lifespan is shortened
Solution Approach 1:
The patent applies periodic polarity inversion to the voltage signal applied to the liquid crystal layer. By alternating the voltage polarity between positive and negative cycles, the liquid crystal molecules are prevented from maintaining a fixed inclination for prolonged periods, thereby eliminating image lag and extending display device lifespan while maintaining stable alignment during each cycle.
2Reliability
If polarity inversion driving is performed by alternating voltage between positive and negative sides, then image lag is prevented and lifespan is extended, but device complexity increases due to additional control circuits
Solution Approach 1:
The auxiliary electrode is designed to serve multiple functions: it acts as a capacitance element for voltage holding, provides a path for polarity inversion, and enables simplified driving control. By integrating these functions into a single electrode structure, the patent reduces the need for separate control circuits while achieving effective polarity inversion and image lag prevention.
Solution Approach 2:
The auxiliary electrode serves as an intermediary element between the pixel electrode and the liquid crystal layer. It mediates the voltage application by providing capacitive coupling that enables polarity inversion without requiring direct complex control of the liquid crystal molecules, thereby simplifying the overall control architecture.
3Ease of operation
If capacity coupling driving method is used to control auxiliary capacitance line voltage, then voltage control is achieved during non-conductive period, but power consumption is not sufficiently reduced
Solution Approach 1:
The patent implements periodic switching between conductive and non-conductive states of the pixel switch, combined with periodic polarity inversion. During the non-conductive period, the auxiliary capacitance maintains the voltage without requiring continuous power supply. This periodic operation allows effective voltage control while minimizing power consumption by eliminating continuous current flow.
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 solution effectively mitigates image lag and extends the lifespan of liquid crystal display devices by alternating voltages, improving display performance and reducing power usage through efficient voltage management.
Implementation Method 1
an auxiliary electrode which is electrostatic capacitive coupling with the pixel electrode
Implementation Method 2
The alignment of liquid crystal molecules included in the liquid crystal layer are controlled by a voltage applied to the pixel electrodes and a voltage applied to the counter electrodes
Data Source
AI summary
According to one embodiment, a display device includes a first scanning line, a second scanning line, a signal line, a capacitance line, and a pixel. The pixel includes a pixel electrode, an auxiliary electrode, a first switch, a second switch, and a third switch. 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 auxiliary electrode, the first scanning line, and the capacitance line. The third switch is electrically connected to the signal line, the second scanning line, and the auxiliary electrode.