• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.1096-1100
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• 2003

A fast Q-tensor method, which can model the defect dynamics in a liquid crystal director field is presented. The method is used to model the defect dynamics occurring during the "warm-up" of a ${\pi}-cell$ device.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.105-108
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• 2005

We demonstrate an electro-optical device based on the flexoelectric effect of a short-pitched cholesteric liquid crystal. By using a dual-frequency switchable nematic, a small amount of chiral dopant and a small amount of phase-separated polymer localized on the surface, we were able to create a device that operates in amplitude (flexoelectric) and phase(dielectric) modes. At high frequency the dual frequency liquid crystal suppresses the phase mode at higher voltage, which improves the switching speed, and thereby preserving the in-plane-switching mode.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.433-435
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• 2005

We have studied the realigning behavior of liquid crystal molecules in liquid crystalline polymer/liquid crystal(LCP/LC) system when they are exposed to external stimulation such as bending and pressing. The birefringence of the LCP/LC in a flexible display device was measured as a function of bending or pressing deformation. The microscopic dynamic behavior of main chain, side chain, and the LC were characterized by FTIR and polarization optical microscopy. When the device is deformed in scattering memory state, liquid crystal(LC) director is found to align from randomly oriented domain state(scattering state) to homeotropic state.

• Korean Journal of Optics and Photonics
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• v.24 no.4
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• pp.168-175
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• 2013

An information display device is a key component in the information society. A liquid crystal display is the most widely used among information display devices. However, its performance still needs to be improved in order to survive in competition with other information display devices. In this paper, we explain the structure and the operation principle of a liquid crystal display device and introduce our recent research activities on liquid crystal mode technology.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.1
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• pp.145-149
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• 2023

In this study, the spectrum changes induced from the doping of phosphor micro particles in a twist nematic liquid crystal cell was observed. The experimental results show that the achromatic transmission can be observed with a proper driving condition, which may be applied to the design of an achromatic liquid crystal device. In this paper, we tried to figure out the spectrum changes induced from the doping of phosphor micro particles. The experimental result of the phosphor powder doped twist nematic liquid crystal cell shows that the achromatic transmission and the wavelength linearly dependent transmission both can be observed with some proper driving conditions, respectively. The result is useful on developing an achromatic liquid crystal device and it can be applied for Vihicle lamp.

• Journal of Information Display
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• v.12 no.1
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• pp.17-21
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• 2011

Aliquid crystal (LC) device switchable between the reflective and transmissive modes without sub-pixel division is proposed. By using dye-doped nematic LCs for the top LC layer, transflective displays with high reflectance were realized. It is expected that the proposed device can be applied to high-reflectance transflective devices for outdoor applications.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.5
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• pp.303-306
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• 2014

In this paper, by using a dual frequency liquid crystal material, we propose a liquid crystal device with a fast response characteristics. The dual frequency liquid crystal material has a positive dielectric anisotropy value at a low frequency. With a high frequency, the dielectric anisotropy becomes negative. Therefore, the relaxation process is governed by not only the elastic deformation, but also the dielectric interaction. The measured decay time and rise time were 0.88 ms and 0.33 ms, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.300-300
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• 2008

In this study, the advanced DuoPIGatron-type ion beam (IB) system was applied to inorganic thin film for aligning liquid crystal (LC). LC alignment on $Ta_2O_5$ via IB irradiation was embodied. As a result of IB irradiation, the homogeneously aligned liquid crystal display (LCD) on $Ta_2O_5$ was observed with low pretilt angles. The $Ta_2O_5$ were deposited on indium-tin-oxide coated Coming 1737 glass substrates by rf magnetron sputtering at $200^{\circ}C$. The deposition process resulted in forming very uniform thin film on glass substrates without any defects. To confirm the application of the inorganic alignment on modem display optical devices, we fabricated twisted nematic LCD and measured optical property and response time. As a result of the experiment, the electro optical characteristics of the LCD fabricated by using IB irradiation on $Ta_2O_5$ alignment layer were similar with the other LCD fabricated by using rubbing process.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.166-168
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• 2009

We proposed a transflective liquid crystal display (LCD) with high aperture ratio using an electrophoretic particle layer (EPL). The transflective LCD consisted of the stacked LC layer and EPL which was acted as a switchable mirror under in-plane electrode structure. Without separation of reflective part and transmissive part in one pixel, a modeselectable display device can be obtained.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.187-190
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• 2005

Alignment pattern of checkerboard was constructed by the stylus of atomic force microscope. Orientational bistability of the nematic liquid crystal was realized on that frustrated surface alignment. Macroscopic orientational switching between two perpendicular directions took place by an appropriate in-plane electric field. The threshold electric fields decreased in both switching directions as temperature increased. The focused laser heated up only the limited domains in the cell including a light-absorbing medium. Irradiating the laser concurrently with an appropriate electric field, we switched the selected unit domains in the alignment pattern. The switched domains maintained stably the switched direction without the disturbance from the exterior. Extending and repeating this process, we realized extremely fine devices of bistable switching.