IPS LCD Residual Image Reduction via Lower Resistance Layers
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Solution Overview
Problem
In-plane-switching (IPS) mode liquid crystal display (LCD) devices suffer from residual image issues due to parasitic capacitance caused by ionized and polarized impurities, which charge and retain DC voltage, leading to image retention even after new voltages are applied.
Innovation Solution
The IPS mode LCD device manufacturing method involves forming a liquid crystal layer and passivation film with lower resistances than the alignment film, using carbon-nitride or tolane-based liquid crystal materials and silicon nitride passivation films, respectively, to discharge the charged DC voltage and prevent parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If an alignment film is used to discharge ionized impurities, then the viewing angle is enhanced, but parasitic capacitance is generated causing residual images
Solution Approach 1:
The patent changes the electrical parameter (non-resistance) of the liquid crystal layer and passivation film to be lower than that of the alignment film. This parameter change enables these layers to discharge DC voltage more effectively, preventing parasitic capacitance accumulation while preserving the alignment film's function for achieving wide viewing angles.
Solution Approach 2:
The patent introduces the passivation film as an intermediary layer between the liquid crystal layer and the alignment film. This intermediary structure provides a discharge path for DC voltage through its lower non-resistance, preventing charge accumulation at the alignment film interface while allowing the alignment film to maintain its molecular alignment function.
2Duration of action of stationary object
If DC voltage is applied for extended image display, then the image is maintained, but the parasitic capacitor charges the DC voltage causing residual images
Solution Approach 1:
The patent converts the harmful effect of DC voltage accumulation into a beneficial discharge mechanism. By designing the liquid crystal layer and passivation film with lower non-resistance than the alignment film, the system creates a natural discharge path that actively eliminates charged DC voltage, transforming the potential harm of prolonged DC application into a self-correcting mechanism that prevents residual images.
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 approach effectively reduces the energy bands of the liquid crystal layer and passivation film, allowing for efficient discharge of DC voltage and minimizing residual image formation, resulting in fainter and faster-fading residual images compared to traditional methods.
Implementation Method 1
The liquid crystal layer and the passivation film are formed to have lower non-resistances than that of the first alignment film
Data Source
AI summary
An in-plane-switching mode liquid crystal display device is disclosed. The LCD device includes: first and second substrates opposite to each other; a liquid crystal layer interposed between the first and second substrates; a passivation film formed on the first substrate in which a thin film transistor is disposed; pixel and common electrodes arranged alternately with each other; and a first alignment film formed on the pixel and common electrodes. The liquid crystal layer and the passivation film are formed to have lower non-resistances than that of the first alignment film.