• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.267-270
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• 1998

In this study, we investigated the generation of pretilt angle for nematic liquid crystal (NLC) in a cell with oblique non-polarized ultraviolet (UV) light irradiation on polyimide (PI) surfaces. It was found that the monodomain alignment of the NLC is obtained in a cell with an angle of incidence of 70∼85$^{\circ}$on PI surface. We consider that the monodomain alignment of NLC is attributed to anisotropic dispersion force effect due to Photo-depolymerization of polymer on PI surfaces. Also, pretilt angle of NLC is generated about 3$^{\circ}$ with an angle of incidence of 70∼75$^{\circ}$. It is considered that the pretilt angle generation in NLC is attributed to interaction between the LC molecules and the polymer surfaces.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.271-274
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• 1998

In this paper, the monodomain alignment of nematic liquid crystal(NLC) in the cell fabricated by one side transcription alignment method on PI surface with side chain were investigated. The LC alignment produced by the transcription alignment method is attributable to a memory effect of the NLC on Pl surfaces. We observed that the pretilt angle of NLC is generated about 3.6$^{\circ}$ in a cell with one side transcription alignment on PI surface. Also, the electro-optical(EO) performance of TN-LCD with one side transcription alignment method on PI surface will be discussed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.885-890
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• 1998

The electro-optical properties of polymer dispersed liquid crystals (PDLCs) depend on dispersion structures and nematic alignment which can be controlled by taking proper liquid crystal/polymer mixtures and process conditions. To achieve excellent electro-optical properties such as low driving voltage, good contrast ratio and negligible hysteresis, we have developed optimization procedure. Under the optimized conditions, PDLC of low threshold voltage less than 3.1 V, high contrast ratio more than 150 and negligible hysteresis were obtained.

• Transactions on Electrical and Electronic Materials
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• v.7 no.6
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• pp.297-300
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• 2006

The response surface modeling of the pretilt angle control using ion-beam (IB) alignment on nitrogen doped diamond-like carbon (NDLC) thin film layer is investigated. This modeling is used to analyze the variation of the pretilt angle under various process conditions. IB exposure angle and IB exposure time are considered as input factors. The analysis of variance technique is settled to analyze the statistical significance, and effect plots are also investigated to examine the relationships between the process parameters and the response. The model can allow us to reliably predict the pretilt angle with respect to the varying process conditions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.109-112
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• 1998

In this paper, we studied on electro-optical (EO) characteristics of photo-aligned twisted nematic (TN)-LCD. We obtained that uniform LC alignment in TN-LCD with linearly polarized ultraviolet (LPUV) light irradiation on polyimide (PI) surface increases according to increasing irradiation time for 10 to 60 min. The voltage-transmittance and response time characteristics of photo-aligned TN-LCD with UV light irradiation time of 60 min were almost same in comparison with conventional TN-LCD were observed. From the results, we suggest that photo-aligned TN-LCD with LPUV light irradiation on PI surface is useful in applying LCD as for rubbing-free treatment method.

• Progress in Superconductivity and Cryogenics
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• v.21 no.4
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• pp.6-8
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• 2019

Iron-based superconductors (IBSs) possess nematic phases in which rotational symmetry of the electronic structure is spontaneously broken. This novel phase has attracted much attention as it is believed to be closely linked to the superconductivity. However, observation of the symmetry broken phase by using a macroscopic experimental tool is a hard task because of naturally formed twin domains. Here, we report on a novel detwinning method by using a magnetic field on FeTe single crystal. Detwinning effect was measured by resistivity anisotropy using the Montgomery method. Our results show that FeTe was detwinned at 2T, which is a relatively weak field compared to the previously reported result. Furthermore, detwinning effect is retained even when the field is turned off after field cooling, making it an external stimulation-free detwinning method.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.201-202
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• 2007

본 논문에서는 두 대의 CCD 카메라 센서로부터 얻어진 영상을 이용하여 실시간으로 입체영상을 생성해 내고 동시에 화질 개선 작업이 실시되는 프로세서를 설계하여 입체 동영상 구현이 가능한 시스템을 완성하였다. 또한, 패럴렉스 베리어(Parallax barrier)를 설계하고 이를 Wide 7" STN(Super Twisted Nematic) LCD 패널에 적용하여 휴대가 용이한 입체영상 디스플레이 시스템을 구현하였다.

• Korean Journal of Optics and Photonics
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• v.12 no.6
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• pp.468-471
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• 2001

A novel method to measure the cell gap of a single-polarizer reflective twisted nematic liquid crystal (TN LC) cell by using a rotating polarizer technique is proposed. By rotating an LC cell, we can measure the cell gap of an LC cell as well as the wavelength dependence of retardation under the condition that the twist angle is known.

• Korean Journal of Optics and Photonics
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• v.10 no.4
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• pp.279-282
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• 1999

We designed and fabricated a single polarizer mode bistable twisted nematic liquid crystal display by employing a wide-band λ/4 retardation film to enhance the dark state property. We theoretically and experimentally confirmed the necessity of a wide- band λ/4 retardation film in a single polarizer mode. We obtained brighter image than previous reflective BTN LCDs.

• Korean Journal of Optics and Photonics
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• v.8 no.3
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• pp.218-222
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• 1997

We fabricated a bistable TN LCD with 180$^{\circ}$ twist angle and confirmed that it has a fast switching response time and a high contrast ratio. We also investigated the effects of the amplitude and width of the reset and selection pulses on a bistable TN LC cell and the conditions of the bistability and the memory time. The range of d/p values showing the bistability is determinded for the pretilt angle according to the rubbing depth.