• Journal of Information Display
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• v.4 no.1
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• pp.1-8
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• 2003

Recent progress in both low pretilt and high pretilt defect free C1 surface stabilized ferroelectric liquid crystal (SSFLC) devices is reviewed. First, by numerical calculation to investigate the balance between surface azimuthal anchoring energy and bulk elastic energy within the confined chevron layer geometry of C1 and C2, it is possible to achieve a zigzag free C1 state by low azimuthal anchoring alignment with a low pretilt angle. The critical azimuthal anchoring coefficient for defect free C1 state is calculated. Its relationship with elastic constant, chevron angle as well as surface topography effect are also discussed. Second, using $5^{\circ}$ oblique SiO deposition alignment method a defect free, large memory angle, high contrast ratio and bistable C1 SSFLC display, which has potential for electronic paper applications has also been developed. The electrooptical properties and bistability of this device have been investigated. Various aspects of defect control are also discussed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.8
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• pp.1793-1798
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• 2005

We model the nucleation and motion of defects in the liquid crystal display device with inhomogeneous surface by using fast Q-tensor method, which can calculate scalar order parameter S and nucleation of the defect in the liquid crystal director field. In order to model the defect, homeotropic aligned liquid crystal cell with step inhomogeneous electrode which has a height of $1{\mu}m$ is used. From the simulation, we can observe the nucleation and line of the defect from surface inhomogeneity and the experiment is performed for confirmation.

• Electrical & Electronic Materials
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• v.10 no.1
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• pp.15-19
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• 1997

The characteristics of the response time and the viewing angle on twisted nematic (TN) liquid crystal display (LCD) and amorphous (a)-TN-LCD without rubbing were investigated. To measure the tansmission-voltage, response time, and viewing angle characteristics, we prepared three kinds of LC cells and then studied the surface liquid crystal alignment effect. It was found that the response time on A-TN-LCD was fast compared to the TN-I-CD, and the weak anchoring strength was attributed to the fast response time on a-TN-LCD. Also, we obtained the wide viewing angle characteristics on a-TN-LCD. The liquid crystal alignment of LCD device for electro-optical characteristics is discussed in the present paper.

• Korean Journal of Optics and Photonics
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• v.18 no.2
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• pp.100-104
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• 2007

We have measured the optical spectra while varying the temperature of photonic crystal fibers (PCFs) with periodic air holes in the cladding. These are liquid crystal infiltrated fibers. For the liquid crystal infiltrated PCFs, we obtained the transmission of several wavelengths at specific temperatures. The transmission power could be reduced by about $10\sim15dB$ by varying the applied temperature in the liquid crystal PCF. We expect that it is applicable as a wavelength switching device in the specific wavelength band.

• Current Optics and Photonics
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• v.3 no.1
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• pp.66-71
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• 2019

Application of liquid crystal (LC) materials to a flexible device is challenging because the bending of LC displays easily causes change in thickness of the LC layer and orientation of LCs, resulting in deterioration in a displayed image quality. In this work, we demonstrate a prototype device combining a flexible polymer substrate and an optically isotropic LC-polymer composite in which the device consists of interdigitated in-plane switching electrodes deposited on a flexible colorless polyimide substrate and the composite consisting of nano-sized LC droplets in a polymer matrix. The device can keep good electro-optic characteristics even when it is in a bending state because the LC orientation is not disturbed in both voltage-off and -on states. The proposed device shows a high potential to be applicable for future flexible LC devices.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.422-425
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• 2006

Recently, studies on orientation of carbon nanotubes (CNTs) dispersed in nematic liquid crystal (LC) and CNTs effects on electro-optic characteristics of the LC device have been performed. In this paper, we summarize interaction nature between CNT and LC, local distortion of the LC director field by motion of CNTs, and effects on electro-optic performances of LC device.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.305-308
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• 2003

We fabricated a flexible ferroelectric liquid crystal (FLC) device containing polymer walls and networks which fix plastic film substrates. The device using 100-${\mu}m$-thick substrates could be bent in a radius of 7mm without disordering the FLC alignment. When sandwiched between polarizers a roll-up display with high-speed grayscale capability for moving-image displays was created.

• The Optical Journal
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• s.98
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• pp.60-66
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• 2005

프로젝터와 프로젝션 TV는 공통적으로 광학엔진내에 신호 처리된 영상 정보를 표시해주는 CRT(Cathode Ray Tube), LCD(Liquid Crystal Device), LCoS(Liquid Crystal on Silicon), 디지털 마이크로 미러 디바이스(Digital Micromirror Device;DMD)등의 디스플레이 소자가 사용된다. 최근 이러한 디스플레이 소자는 소형화·경량화 되어지는 추세에 있으며 무겁고 두꺼운 CRT보다는 LCD를 이용한 프로젝션 시스템들이 속속 출시되고 있다. LCoS 및 DMD를 이용한 시스템들도 출시 또는 개발되고 있는 실정이다. 특히, 현재까지는 LCD가 주류였지만, 고해상도 구현에 유리한 반면, 개발속도가 느린 LCoS에 비해 하이 콘트라스트(High Contrast) 구현에 탁월하고 개발 속도가 빠른 DMD를 이용한 프로젝션 시스템의 개발 및 출시가 주로 진행되고 있다.

• Journal of Satellite, Information and Communications
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• v.10 no.2
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• pp.90-94
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• 2015

We stuidied liauid crystal alignment treatment using solution process for making thin oxide layer in liquid crystal display. It is the one of very effient and popular process in making thin oxide layer in electronical industrial fields. Particularly, this process has highly potential value in liquid crystal display industrial fields because it cause automatically induced alignment process without tranditional alignment process in liquid crystal alignment process. We made several different kinds of mol density solutions using strontium oxide solution. And those solutions were treated for solidification layers using annealing process for 2 hours. And we stuided pretilt angle properties of these alignment layers of strontium oxide for clarifying the relationship of liquid crystal molecules and thin strontium oxide layer. And we also tested the existence of strontium oxide thin layer on substrate using XPS measurement. We expected the hig gain of electro-optical properties in liquid crystal display using strontium oxide thin layer because it has high K property material than the other metal-based oxide layers. In this results, we measured 1.447 to 1.613 thresholds volts as 0.1 mol to 0.4 mol density in 0.1 mol density steps. This is significant better characteristics than conventional liquid crystal display as higher than 1.85 thresholds volts. And it make possible to making next-generation liquid crystal display which present low-power consumption and wide gray scale in liquid crystal display.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.308-309
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• 2008

We have proposed a high performance liquid crystal display using two thin film transistors (TFTs) for the large size TFT-LCD desirably 42inch WXGA panel for TVs. The device generates stronger electric fields to reorient liquid crystals than that in the conventional IPS device because the voltages with opposite polarity with respect to the common electrode are applied to each finger-type electrode. As a result, the operation voltage of 2Tr-IPS mode can be decreased and the transmittance can be increased compared to conventional IPS device. Consequently, the 2Tr-IPS has all the advantages over conventional IPS from large size point of view.